Wednesday, December 29, 2010

Cutting Registration to Printed Fabric Materials

Written By Mark Batson Baril

A brief question:
I am in the promotional product's business. Currently I am preparing to manufacture a product where I will need to cut sheets of fabric, such as neoprene and ultraseude (polyurethane) into (140) 3 inch (76.2mm) X 1/2 inch (12.7mm) printed strips. I have contacted various die cutting facilities but there are potential accuracy problems since the sheets may not be perfectly shaped and may not align perfectly. I am assuming that some form of laser guided cutting would illiminate this concern?

And a brief answer:
Right off the bat I can think of a few ways to approach the project you are talking about. The fact that your printing may wander and not be in accurate/consistent registration to any corner of the sheet is the main problem.

Registration marks could be printed at the same time as your main printing. These could be designed as either simple slash marks or simple target type circles. This then opens up your options.

    1. Use the registration marks to align your materials in any type of cutting machine. Diecutting, guillotine, and laser immediately come to mind. A simple retractable and clear overlay that has been pre-struck acts as your line-up. Each individual sheet of material to be cut is lined up under the retractable sheet. Once the part is aligned and fixed to the cutting bed the clear overlay is moved away and the impression is made for a near perfect cut every time. 2. Other tooling methods would include using see through tools that could be registered one at a time on press by the operator. A clear Polycarbonate (*Lexan) or Acrylic based steel rule die or clicker type die may be your best bet. 3. Circle type registration marks can be used with a *Spartanics type machine that will automatically pre-punch a perfect hole at the mark. This can then be used in conjunction with a tool that has retractable registration pins. This method is used all the time in the membrane switch and flex-circuit industry.Optical registration is also an option on many diecutting machines and may be a good method for your particular job.

Each of these methods will result in accuracy of ± .010"-.015" (.254mm) depending on the operator. These ideas are slow but luckily your quantities are small. If you increase your quantities you will have to inquire about better ways to register to the flexible material you are using.

Wednesday, December 15, 2010

Rotary Steel Rule Diecutting Hard Anvil

Written By Mark Batson Baril

I recently read a press release that said that a rotary steel rule die could be used cutting against a hard steel anvil. I thought that you could only cut into a soft blanket with this type of die? Could you give a brief explanation of the benefits vs. soft anvil, differences in the tool/press, make-ready differences or comparisons to flatbed steel-on-steel and anything else that could clue me into this new technology? Is it new technology?

This is not new technology. It has been around at least 20 years. Marumatsu Company manufactured a 1350mm & 1700mm (53" & 67") diameter bottom cutter with a stripping section. United Machine has also made a 1.700mm (66") S-S top cutter with a stripping section.

The die is built in some ways similar to a flat die with extra considerations such as the straight rule is always mitered to curved and curved cut pieces are usually no longer than 10 inches. Soft anvil rule is serrated in order to penetrate the urethane blanket where as the S–S rule is a continuous bevel (non-serrated). The rule used in S-S cutting is 4pt center bevel edge hardened with a soft base. The idea here is to run-the-rule-in so that it levels itself off before actual diecutting begins. Rule heights around the cylinder vs. across the cylinder are varied by about ,075mm to ,127mm (.003" to .005") and the final heights are established during the run-in process on press. The hard anvil cutting surface is made out of an 85+ Rockwell steel and stands up to a great deal of pressure. As you can imagine, much of the success you achieve with this process comes from good maintenance of the press and well made and maintained tooling. The rule must be consistently perpendicular to the base surface and that tool base material must be able to maintain a perfect curvature. Excellent tool building and on-press “tricks” account for the success or failure of this process.

The benefits over soft anvil rotary cutting are that you can achieve the same rotary speed with the accuracy and cut quality of flat-bed diecutting. Because the surface you are cutting against is consistent, you avoid the dimensional variance that you get during soft anvil diecutting. Recent improvements in blanket re-surfacing and tool calibration to the soft cutting surface during prodcution have improved finished part tolerances, however there is still a big difference between the two processes.

Typically a stripping blanket is manufactured with each cutting die. The blanket is made from a ,75mm (.030") mounting material with "T" and "L" shaped stripping pieces attached to push off scrap in a section immediately after diecutting.

Because the cylinders run 1:1 in their gearing (opposite to a soft anvil cutting where the soft blanket cylinder will strike the cutting blades in a different spot every turn), the make-ready process can be made in several ways. Upon running the die and beginning the diecutting process and after achieving 80 percent good cutting, make-ready tape is applied to the die cut anvil in the non-cutting areas. This raises the substrate and helps the cutting in the non-cutting areas. Some companies will also make-ready under the die for fine tuning. This is typically the wrong way to go when making ready in flatbed applications but because there is no secondary steel cutting plate on top of the cutting cylinder, behind the die may be the only choice. The tricks here are in choosing a rule that will self-level and having an operator that is level headed enough to make it self-level. The 1:1 gearing/cylinder ratio also lends itself well to using matrix or other counter materials to form the scores.

From what we can see out there, this process seems to be a fairly rare one. Not many presses were made with this capability and the tricks of the trade needed to be successful seem to have taken a toll on its popularity. The companies that are using steel to steel rotary with SRD’s are enjoying some terrific benefits!

Some of the stories that helped answer this question and put together this summary were told by;

  • Thomas A. Sporleder – Printron

  • Mike Porter – The Rayner Company

  • Tommy Moore – Stafford Cutting Dies

    Thanks Guys!

  • Wednesday, December 1, 2010

    Laser Cutting

    Written By Mark Batson Baril

    (LASER) Light Amplification by Stimulated Emission of Radiation

    Lasers come in many different shapes and sizes. They range in usage from the standard supermarket scanner to those being developed as part of military defensive systems. The laser has existed in usable form since the mid 1960's.

    The type used almost exclusively for cutting a wide range of materials is the CO2 gas laser. Hole drilling is typically done with solid state YAG lasers.

    A laser beam is created by the introduction of gas and electric current to a sealed chamber. As the electricity breaks down the gas an energy is released and resonates between mirrors within the chamber. As it resonates it increases in intensity and at it's optimum is released through a partially transmissive mirror. The beam is then directed to a focusing lens and is further intensified. At this point the laser beam becomes a usable cutting device.

    Some advantages of cutting with lasers include, the ability to cut incredibly complex shapes with no tooling or set-ups. This makes them perfect for production or prototype runs for a huge variety of different products.

    Laser cutting systems cut quickly and very accurately through a wide range of materials. In general, for steel, laser cutting lies between cutting with wire EDM, which is more precise but slower, and plasma, which is less precise but faster. They go well beyond the range of these other methods as well in that they can cut through just about anything within certain thicknesses.

    Given the right material and type of system, tolerances can be held to ±.0005"(.0127mm). Lasers can be found most commonly being used to cut:

    • Most types of steel and aluminum. Large lasers will cut up to 1"(25.4mm) steel and .250"(6.35mm) in aluminum.
    • Paper
    • Wood, plywood, hardwoods
    • Rubber
    • Most Plastics - Acrylic

    When matched to a suitable motion control system, laser cutting provides extremely accurate cuts with a high degree of repeatability over a wide range of materials and shapes.

    Tuesday, November 23, 2010

    DIe Cutting Wood

    Written By Mark Batson Baril

    The question/problem came to Cut Smart basically in this form:

    Designs in Wood, Inc.(alias name for case study) manufactures over 400 different sizes and shapes of small wooden parts in Eastern White pine ranging in thickness from 1/8" (3mm) to 1/4" (6mm) with a surface area under 6 square inches (152mm). Generally the surface areas are 3 to 4 square inches (75 - 100mm).

    Our current process involves bandsawing 8/4 stock and then slicing and sanding each part. This is time consuming and we are looking for a way to lower our manufacturing costs. We have looked at laser cutting but have ruled it out because our secondary process requires a finished, unburned edge.

    I am not completely familiar with steel rule die cutting, and wonder if it is something that we might be able to use. I would be interested in the following:
    • Can this type of wood be cut with a steel rule die (tolerances of .010" to .020" (.25 to .50mm are OK)?
    • What kind of equipment (press tonnage/manufacturer) would be required?
    • The cost of a typical steel rule die?
    • The life of such tooling in terms of number of impressions?
    • The finished edge appearance?

    We answered in this way;

    Because we don't know all the shapes you are cutting it is hard to say what your final results will be. The more flowing and rounded your shapes are the better the results will be. Sharp corners and thin areas of image will be tough to cut. There are several types of dies that could work including steel rule dies, clicker dies, EDM cut specialty punch dies and matched metal tooling. All of these are possibilities depending on the shapes you are cutting and your overall volume. Tolerancing like you mentioned will be tough to hold on any but the machined tools and punches.

    Eastern white pine is a fairly soft wood that can be cut on a steel rule die. The 1/8" (3mm) thickness will be a great deal easier and will give much better edge results than the 1/4" (6mm) material. We have worked with several companies that build models from wood. They use steel rule dies as well as other cutting tools that cut in one hit. They have had excellent results with all of the types of cutting dies mentioned above. Tools other than the steel rule die will work well, but the steel rule die may be the place to start because of its relatively low cost.

    The type of press and the tonnage needed would largely be a factor of how many you plan to cut at the same time on a sheet. One at a time like you describe would require very little tonnage 1 - 5 tons and a very common hydraulic type press would work well. Costs may range from $5,000 used to $20,000 (USD) new depending on the size and style.

    A simple one up steel rule die would cost in the range of $100 to $300 (USD) depending on the shape and who you buy it from. The more images you add to the tool the cheaper each image becomes. Specialty punches and machined tools would cost substantially more.

    Although we have seen manufacturers with millions of impressions on their tools, the material you are cutting is tough. I would estimate no better than 10,000 hits from a tool before it needs a reknife.

    Generally you will find that an extremely hard, thin rule with a very long bevel will work well. Support the rule as high as you can with your base material for best results. There is a rule called "Razor Rule" that works excellent for cutting wood. If diecutting is still something that sounds like it would fit your needs, I suggest connecting up with a local qualified diemaker or diecutter that would be willing to cut a few samples for you. This will show you the type of product you can get and how economical this process may be for you.

    Depending again on the shape of the cut, your edge results will probably have a slight roundness to the top and a square, sharp bottom. Grain, moisture content, sharpness of the tool, cutting surface wear, will all effect the results. Your with grain cut will most likely be of better quality than the cross grain cut. Knots will be a problem!

    High speed CNC routering is another method we have seen used that performs the same way the laser does without the burned edges. Although slow compared to cutting with a die, the method may make sense if laser cutting came close to making sense for you.

    Tuesday, November 2, 2010

    Die Cutting with Rule Joiners

    Written By Mark Batson Baril

    Cut Smart recently dealt with this question:

    Does anybody out there know how to create a perfect joint where radii come into one another on a steel rule die? We have more than one customer that insists that their radius cornered gaskets be run with a common cut in both directions to save material. On the other hand we have a diemaker that insists that he must have a double knife in order to put in the radius corners. There must be a way but we’re diecutters not diemakers and have no idea how. Should we find a new diemaker or is there some information out there they could use? Thanks!

      For the common application where a steel rule die will be used in some type of flatbed cutting operation, the best answer we can give is to use Rule Connectors - A.K.A. - Rule Joiners - These are a love/hate product. Some people swear by them; others swear at them! Rule Connectors are a solid steel machined punch which replaces the regular steel rule at tough to make joints. Rule Connectors typically replace normal rule where rules meet at a radius corner.

    The Plus Side is this -
    • At the point where most diemakers have an major problem making a joint that works and is accurate, especially in tough materials, the rule is replaced by a virtually indestructible piece of machined steel that is perfect. The joints are moved to an easier and more desirable location usually on a straight-away and the problem is solved.
    • They are readily available, in a variety of different radii.
    • The Custom possibilities are endless.

    There are two main drawbacks -
    • One is how the rule and punch is installed. Rule Connectors typically have "V" notched ends that join rule to the punch. If you do not cut the rule to the right size or the bevel on your rule is off-centered, you will pull your hair out trying to get the tool to work properly. However, if it is installed correctly, you will have virtually no spaces or natural nicks in the rule pattern. When you put it together right, it works great, especially on materials that love to separate rule.
    • The other drawback is the cost of the Rule Connectors. They cost roughly $20 to $30 (USD) each. Most of the time the cost can be justified by eliminating downtime, rule repairs and material waste. If you have a small run, the cost may be prohibitive.

    To answer the question more pointedly –

    The diemaker may be right! Even though there are rule joiners on the market, you will leave yourself open for more actual natural nicks than if you had allowed for space between your cavities and had made only one or two natural nicks in each cavity. Depending on your customer’s final product, this may be a big factor when selling the job in the first place.

    Other answers in a case like this one are numerous - Could the product be more easily cut in a rotary application where a solid machined or chemically etched tool may be of use? No joints here! Also it may be worth thinking about a fully machined punch or die that actually outlines and cuts the entire image without any joints. More expensive, but in some cases that doesn’t matter at all. Have you thought about, for short runs, laser cutting, waterjet cutting or CNC Knife cutting machine production? All of these are methods that are being used and are working well in the right situations.

    Rule joiners are not new to the market. As is the case in many situations, the usual for one manufacturer is the unusual for the next. Good luck in all your cutting adventures.

    Friday, September 10, 2010

    Thin Foam Diecutting

    Recently a manufacturer came to us with a production problem. It went something like this:

    We have been over the edge with one particular job recently and could use some advice. We have a customer who has us diecut promotional models from 1/16" (1.587mm), fairly dense, polystyrene(foam cups are made of this). About ten different models are cut on separate steel rule dies. Each die runs the same part in up to a twenty on configuration. All the dies run between 1,000 and 2,000 inches of cut and are approx. 24" x 36" (610 x 918 mm). We use a 1 1/2 pt long double bevel rule and the dies are all rubbered solid with relieved areas in the bigger open spaces. We cut this job on a large clamshell type press and have had very good results cutting into a nylon (plastic) plate. Our problem is that we have run into one particular tool that just will not cut. Some areas will cut and others will not. We have made-ready forever on this job and feel like we know what we are doing, yet we get no where! Our diemaker has checked and rechecked the rule and says it is still good. The problem areas tend to be in areas of more rule concentration, some rules being as close together as 1/8" (3.175mm), yet similar situations have yielded better results. Help !

    OK lets approach this with pure logic. Given your information filled question we can make a few assumptions;

    Since you have run similar jobs before and had good results…

    Tonnage Factor or what pressure your press is able to develop is adequate to get the job done. If you had not run similar jobs well, this would be extremely important to look at.

    Die Materials meet the needs of the job at hand. A double long bevel ("razor rule") or sometimes even a micro-serrated rule usually will work great with this type of foam. Side-face rule may even work better for you in some areas depending on the shape.

    Cutting Plate made of a dense and durable plastic such as nylon is well suited. We often recommend that diecutting, especially in long runs, be made as a steel blade onto a steel cutting plate, but foam is a totally different animal. If it works with the rest of your dies it should work with this one.

    Areas to look at a little more closely are;

    Ejection material - By rubbering a tool with a solid piece of ejection material many problems can be both eliminated and created. In this case where you have what sound like some very small areas you may be creating zones in which the foam cannot be easily compressed into. Remember the idea of ejection is to move freely with the stroke of the cut and then still have enough "kick" to remove that part. It may be worth trying a denser "gum type" rubber that fits your narrow areas ("areas of concentration" as you put it), more loosely. This will allow the ejector to move downward and still have the power to pop that part out. You could start by removing all the rubber. Can you get it to cut now? If so, then more than likely some experimenting with different materials for this one tool will yield good results.

    Die Ruling can also be changed to incorporate side bevel rules in the area giving you problems. By taking the material being cut and pushing it towards larger open spaces rather than crushing it into the small slot, you can relieve pressure and perhaps gain some cutting power in that area.

    Material Type - Are you sure the foam material you are purchasing is the same density and make-up as last time you cut for this customer. A slightly different material may knock out some of the earlier assumptions we made. I know this is a weak point, but in some situations you need to look at every angle!

    The Impossible Image - We have certainly run across situations before where an image cannot be cut. In this case, where you have rules that are very close together compared to the thickness of the material, you may have to take a step back and look at the actual design of the part and the limitations of the die / press / material / etc... . Can the image be changed to eliminate the problem areas ? Will your customer kill you if you even suggest such a thing? Can this be avoided in the future by working with the designer of the part?

    So logically, assuming that we have all the information correct, we have eliminated the tonnage factor, die materials, cutting plate problems and make-ready. Material type is a weak one so lets forget it for now. I would concentrate on ejection material problems first, die ruling second, and then as a last resort start talking and investigating problems with the design of the part vs. the capabilities of the process.

    As it turned out in this case the ejection material was able to be changed enough to solve the problem. From that point on the diecutter became involved in the design process from the very beginning and new projects seem to be flowing smoothly.

    Tuesday, August 31, 2010

    Glue Assists- Tricks of The Trade

    Written By Mark Batson Baril

    "If the glued part of the product ever fails then we are not selling boxes, we are selling flat pieces of nicely printed paper." Quote from a very determined folding carton Glue Department Manager.

    WHY do glue assists work better when they run across the grain as opposed to with the grain? Most people say they just work better - most don't know why - they just do. Is there anything written down explaining why?

    Let's start this answer with another question -
    WHAT is a glue assist?
    A glue assist is well known in the folding carton and printing industries and rather unknown in most of the rest of the diecutting and converting industry. Glue assists were developed as a method to break through the clay coating, varnish coatings, UV coatings etc… of paperboard so that the water soluble glue could penetrate the soluble fibers of the inner core of the board. A series of knives are placed into the die (usually in the glue flap area). These knives are set at a height typically 30% of the overall stock thickness lower than the through cut knives. This partial cut gives the glue more adhesion between the two glued surfaces. If the board is pulled apart, the top layers of the carton board (covered by the slick coating) must tear apart before the carton surfaces will separate.

    The penetration of the knife also adds to the actual surface area that the glue has to adhere to. This exposed area must be formed in a way that exposes fibers and stays open through the gluing process. A cross grain cut will tend to stay open were a with grain cut will tend to close. By running the specialty rule that is forming the glue assist pattern across the grain, we force more fibers to be exposed. For example if you were to take a piece of pine, lets say 1/2" thick, and break it with the grain then the woods' cellulose fibers break in long strings. Should you take the same piece of wood and break it across the grain the cellulose fibers will splinter in longer slivers and expose more of the interior of the wood. The same happens with the paper board. By penetrating the material across the grain the pressure on the inner fibers forces the same cellulose fibers to break and splinter exposing the inner fibers to the soluble glue allowing for greater adhesion.

    One concern is that a number of companies add glue assists to the flaps of their seal end cartons and then seal the carton using hot melt non-porous glue in their cartoning process. Although not as big a help as with a penetrating glue, glue assists still help in that the hot melt glue will form around the broken and exposed fibers. The general rule is that unless the product is being spot glued in only a couple of small areas, the use of glue assists will help the strength of the box, not hurt it.

    Most die shops and diecutting shops have a very specific pattern they use that they know is better than the competitions'. This is to say that there are many patterns that are common and each has it's own reason for effectiveness. Some shops use a simple straight perforating rule that cuts in just one direction. Others use wave perfs or half a zipper rule that cuts in both directions to the grain. Whatever the case may be in your shop, keep in mind the cross grain factor to help make your decision.

    Tuesday, August 24, 2010

    Applying Phenolic Counterplates

    Written By Mark Batson Baril

    Phenolic CounterPlates On-Press Application for Spray-on Glued Plates
    Get the Press ready:
      1.Get the press ready with a cleaned cutting plate locked in place with the spot sheet and any other make-ready in place. Make sure the cutting plate is locked in and in ready for the entire run position. No movement is allowed in this location.
      2.Set up the steel rule die ready for the run, locked into the chase, spot sheets, etc..., all in place.
      3.The counterplates must be applied to the cutting plate before any bringing up of impression or patch-up has started.
    Get the Counter Plates Ready:
      4.Put the registration pins on the plates with the rubber seaters on the pins. Pins and rubber go on the side with the channel cuts. Make sure you know how the orientation works and where the plates attach to the die.
      5.Set-up a spraying area (paper sheet) so that all the plates can be sprayed at one time. This area needs to be close to the die when it has been slid out of the press. Place the counterplates pin side toward the sheet, flat side up ready to be sprayed with 3M #77 glue. Make sure the plates are oil and debris free.
      6.Spray all the plates at one time with the glue. Be careful to get enough glue on but not too much. Too much glue will allow the plates to move and shift after they have been stuck to the cutting plate. The glue will stay tacky for quite a while so don't panic that they will dry too soon.
    Apply the Counterplates to the Die:
      7.Touch the edges of the plates only and locate the plates to the die using the pins to start the line-up. Use a small ball peen hammer to tap the counterplates into the die as evenly as possible. Tap only on the locating pins as damage to the plates is possible if they are hit directly. A very small amount of water or saliva on the tip of the hammer will stop the glue from becoming a problem when hammering.
      8.The plates need to be tapped down as close to the die as possible in order to clear the press when the die is slid back into the press. The plates should not be tapped down to the point where they start to buckle or bend due to contact with parts of the die. If they do curl up not only will they hit the press upon sliding the tool back in but they are likely to pop away from the locating pins causing a non-accurate line up.
    Apply the Counterplates to the Cutting Plate:
      9.Slide the die back into the press. Lock the die in place where it will sit every time it is slid back in. No movement in this registration is allowed.
      10.Bring the impression up and leave it on for approx. one minute. Bring the impression off.
      11.Slide out the cutting plate and using a block of wood or plastic and a hammer, gently tap all the plates in place to make sure the glue has set and there are no parts of any plates that are curling away from the cutting surface. Applying Tape to the lead edge is an option but should not be needed if the counterplates have been made with a skived lead edge.
      12.Return the cutting plate to its original position and start the make ready process.
      13.As an option, the die and plate can be dusted with a small amount of printers powder in order to stop any excess glue from adhering to the sheet.
  • Depending on the size of the tool and the number on, the entire process above can be broken down into sections or parts of the image to be applied. This may allow better control over the drying of the glue.

  • For those press operators familiar with make ready using matrix with common plastic locators, the general application of phenolic counterplates is nearly identical in every way but the gluing stage.

  • Phenolic counterplates are now available with self adhesive tape already in place in order to save a bit of time and to make the process more convenient. The disadvantage of this type of plate is that they are a bit harder to make and using the plates a second time around is harder due to hard to remove adhesives.

  • Tuesday, August 17, 2010

    Non Stick Diecutting

    Written By Mark Batson Baril

    That job needs to be running at 145 strokes per minute, your parts are stuck in the die on every third impression, and the job is getting hotter by the minute. Now what!

    Everyone has the problem, and everyone admits it at one time or another. Whether it is to your fellow worker, your customer, or to your boss, we have all had to admit that we just can’t get the parts to come out of that tooling fast and clean enough. It’s quite a dilemma. Tons of money has been put into planning materials, and printing, and tooling, and the right press, and the right operator, and when the time comes to put it all together we just can’t get the parts to do what they’re supposed to do. There are many ways to set-up ejection. In fact there probably should be a different way of setting up ejection for every material there is out there. Ejection rubber comes in every durometer, cell type, surface emboss style, recovery rate, thickness, and color the mind can imagine but sometimes there is another piece to the puzzle that rubber just doesn’t cover. Let’s tackle a couple of parts to this puzzle that many of us have either never tried or have never heard of.

    Puzzle Part # 1

    DriCote by Bostik – It’s not too often that we talk about a specific product but what the heck, this stuff may be the miracle drug for the cutting press operator. Spray this product on your cutting blades and the parts will just fly out of the press.

    DriCote is a Blade and Bit cutting lubricant that is sprayed on. It’s most typical application is in the woodworking industry where it is sprayed onto saw blades, router bits, joiner blades, etc…. . It adheres and dries in just seconds and depending on the material you are cutting, it can create a wide variety of advantages. By spraying it on cutting blades in a typical diecutting operation – steel rule and specialty tooling - it will have some of the same effects expected in the woodworking field. It will prevent resin/glue build-ups from just about any source. It can extend blade life due to reduced friction. It reduces the heat effects caused by friction and it contains no silicone or petroleum oil making it safe for many applications. We don’t recommend DriCote for medical and food products but for your run of the mill adhesives and foams it is nearly contaminant free. It can also reduce the tonnage needed to cut. Most of all though, in a difficult die cutting situation, it can enhance the quick ejection of the parts from the tool and in many cases will keep that residue build-up from happening at all.

    In particular I have had a recent exposure in the foam cutting field where the normal drag caused by residue build-up from repeat cutting on medium density open cell foam was virtually eliminated. A fast moving press that had been brought to its’ knees several times per hour for tool cleaning is now operating at non-stop full capacity with two applications per day of this lubricant. Given the right situation, this product can work wonders.

    Puzzle Part # 2

    Feed-Thru Punches on Steroids - How many times has the speed of your press, the waste free quality of your parts, or the length of time needed to set-up your job been effected by a specialty material not working well with the feed thru punches you just bought off the shelf? If this is a problem, even every once in a while, keep reading.

    Recently I have encountered specialty feed-thru punches. Yes, I found out that not only can I order special diameters on the cut edge, the base size and the ejection bore, but a feed thru can be specially ordered to work well for certain materials. The last items that can be specially ordered are the exterior cut angle(s) (bevel angles), the interior “grab the waste” lengths, and the interior bevel angles for cutting. By combining these factors with tough to feed material specs, a sometimes difficult situation can be made easier or possible. Ask your current supplier about these special order items the next time you are having troubles or anticipate a problem with a new material or shape.

    A recent experience led me to the KEN KUTS-ALL PUNCH. In this particular case the punch was built as a specialty item for the abrasives industry. Because the tooling must cut through two very different types of material and then grab and pull off the cutting plate a thick and tough to cut material, the angles, depths and hardness had to be changed to make the punches work well. The result is now an in-stock item that cuts longer, grabs better, and sets-up faster than the standard punch for the abrasives industry. You will pay more, but in the right situation they are worth their weight in gold.

    Filling your pockets full of tricks makes you a specialist in your field, so keep in-tune with the latest and please share some when you can. We'll look forward to hearing your tricks of the trade!

    Tuesday, August 10, 2010

    Pre-Press Counter Plate Validation

    Written By Mark Batson Baril

    What is the best way to validate the accuracy of the counter plates produced, to the die, without the benefit of a press or XY coordinate inspection machine?

    There are several parts of a typical counter plate that need to be checked before it goes to press. Those parts include:
    • The thickness of the counter plate material
    • The width of the channel that was cut
    • The depth of the channel that was cut
    • The size of the locating holes that were cut
    • The actual image that was cut
    • The size of the image that was cut

    How each of the parts is passed through Quality Control varies from shop to shop. The most common are outlined here. Specifications for each tool set must pass with the tooling through the QC process. Your quality control people are only as good as the information they are provided with. Training in what's important to inspecting a counter plate is also vital to the quality control.

    The thickness of the counter material
    This is very important as the overall thickness controls the overall emboss we get when the creasing rule enters the counter. Typically a spot check is made of two or three points on each counter with a vernier. ±.001" (±.025mm) is the standard thickness deviation allowed within the industry.

    The width of the channel that was cut
    The width will typically vary with the grain of the board you are working with. Both the with the grain and against the grain width should be at least spot checked within the counter plate. Again a vernier is typically used to check this width. The channel width should fall within ±.002" (.052mm) of the nominal dimension.

    The depth of the channel that was cut
    Again an extremely important factor in how well a tool set will work together. More than any other variable, this is the one that may be out of tolerance. Any up and down movement of the material during production will produce results that may not work. Unlike the width of the channel where the constant tool produces a fairly constant channel, the depth relies on the up and down tolerancing of the machine head and the ability of the machine to hold the material in place. Spot checking the depth with a micrometer is standard practice. Typical tolerancing is ± 10 % of the overall depth of the channel.

    The size of the locating holes that were cut
    Here's a simple one that really matters to the press person. If the holes are to small it's a nightmare to get your pins in the plates. Nobody wants to have to take the time to ream out the holes in pre-make ready or worse yet, on press! If they are too big you'll have to be a magician to get them to stay with the die long enough to make that first impression. You can use a vernier to measure but that's tough to be accurate with a round hole. One of the actual pins that will be used on press is often the best bet for a great and practical QC. Spot check all your plates. The standard deviation allowed is ±.002" ( .052mm). Another excellent measuring device to use is a standard gauge pin. This especially works well if you are a commercial shop and your various customers use various sources for their pins. Set-up the size you need to give them and go with it based on the gauge pin.

    The actual image that was cut
    The actual image we refer to here means differentiating between creasing / cutting / perfing / cut scoring / etc.... Making sure that there are no channels missing and that all of your cut backs stay far enough away from the cutting areas. Again spot checking is most commonly used by putting in few locating pins and actually laying the plate on top of the knifed die (it's easier before the die is rubbered). Check that everything that should be there is there and that areas that should not be there are not. There's no standard tolerancing on this, it's either right or wrong.

    The size of the image that was cut
    An XY Coordinate measuring machine is a great tool to have in your shop for many reasons - measuring counter plates is not one of the reasons. The amount of time and effort that would be spent measuring each and every counter plate would slow your inspection department to a halt and there are not too many customers that would be willing to pay for this service. So how do we get comfortable with the fact that we really are not checking each and every channel in our plates?

  • Calibrate your Counter plate machine as you would your laser, your bending machine, or your XY coordinate measuring machine. When you're comfortable with the fact that your laser and your counter plate cutter are cutting within tolerance, then you can start to relax about you final product.

  • Most companies again perform a spot check by laying the finished plate over the finished die. You will be able to see whether it lines up or if it's questionable. This is done at the same time you are looking for discrepancies in the image that was to be cut. Again this is the fast down and dirty method for checking your tooling.

    Two other methods used in practice include:
    1). Produce a one up vinyl of the carton or product to be produced and use it as an overlay to check the plates. Make sure you are comfortable with your plotter accuracy by calibrating it along with the rest of your equipment.
    2). Take the laser cut die board before it is knifed and lay it on a light table. Take the counter plates and fit them to the die board. Because phenolic counter plates are see-through at the cut channel, you will be able to see whether the light coming through the die is locating to the plates. This method only works for steel counter plates if you have Superman working in your QC department. The only company that we have been able to find that has this ability is Metropolis Die Company.

    We hope this has helped in your quest for the best possible checks on your system. As always, quality leads the way in being the best at anything.

  • Tuesday, August 3, 2010

    Rotary Steel Rule Diecutting Hard Anvil

    Written By Mark Batson Baril

    I recently read a press release that said that a rotary steel rule die could be used cutting against a hard steel anvil. I thought that you could only cut into a soft blanket with this type of die? Could you give a brief explanation of the benefits vs. soft anvil, differences in the tool/press, make-ready differences or comparisons to flatbed steel-on-steel and anything else that could clue me into this new technology? Is it new technology?

    This is not new technology. It has been around at least 20 years. Marumatsu Company manufactured a 1350mm & 1700mm (53" & 67") diameter bottom cutter with a stripping section. United Machine has also made a 1.700mm (66") S-S top cutter with a stripping section.

    The die is built in some ways similar to a flat die with extra considerations such as the straight rule is always mitered to curved and curved cut pieces are usually no longer than 10 inches. Soft anvil rule is serrated in order to penetrate the urethane blanket where as the S–S rule is a continuous bevel (non-serrated). The rule used in S-S cutting is 4pt center bevel edge hardened with a soft base. The idea here is to run-the-rule-in so that it levels itself off before actual diecutting begins. Rule heights around the cylinder vs. across the cylinder are varied by about ,075mm to ,127mm (.003" to .005") and the final heights are established during the run-in process on press. The hard anvil cutting surface is made out of an 85+ Rockwell steel and stands up to a great deal of pressure. As you can imagine, much of the success you achieve with this process comes from good maintenance of the press and well made and maintained tooling. The rule must be consistently perpendicular to the base surface and that tool base material must be able to maintain a perfect curvature. Excellent tool building and on-press “tricks” account for the success or failure of this process.

    The benefits over soft anvil rotary cutting are that you can achieve the same rotary speed with the accuracy and cut quality of flat-bed diecutting. Because the surface you are cutting against is consistent, you avoid the dimensional variance that you get during soft anvil diecutting. Recent improvements in blanket re-surfacing and tool calibration to the soft cutting surface during prodcution have improved finished part tolerances, however there is still a big difference between the two processes.

    Typically a stripping blanket is manufactured with each cutting die. The blanket is made from a ,75mm (.030") mounting material with "T" and "L" shaped stripping pieces attached to push off scrap in a section immediately after diecutting.

    Because the cylinders run 1:1 in their gearing (opposite to a soft anvil cutting where the soft blanket cylinder will strike the cutting blades in a different spot every turn), the make-ready process can be made in several ways. Upon running the die and beginning the diecutting process and after achieving 80 percent good cutting, make-ready tape is applied to the die cut anvil in the non-cutting areas. This raises the substrate and helps the cutting in the non-cutting areas. Some companies will also make-ready under the die for fine tuning. This is typically the wrong way to go when making ready in flatbed applications but because there is no secondary steel cutting plate on top of the cutting cylinder, behind the die may be the only choice. The tricks here are in choosing a rule that will self-level and having an operator that is level headed enough to make it self-level. The 1:1 gearing/cylinder ratio also lends itself well to using matrix or other counter materials to form the scores.

    From what we can see out there, this process seems to be a fairly rare one. Not many presses were made with this capability and the tricks of the trade needed to be successful seem to have taken a toll on its popularity. The companies that are using steel to steel rotary with SRD’s are enjoying some terrific benefits!

    Some of the stories that helped answer this question and put together this summary were told by;

  • Thomas A. Sporleder – Printron

  • Mike Porter – The Rayner Company

  • Tommy Moore – Stafford Cutting Dies

    Thanks Guys!

    Please contact Cut Smart if you would like more information on this subject.

  • Wednesday, July 28, 2010

    Die Cutting Presses / Finding the Right Press

    Written By Mark Batson Baril

    Developing The Best Cutting Method For A High Volume Product - A Case Study

    An engineering team for a large automotive subcontractor needs to develop a best method to produce parts in large quantities. Here are the details of that project and hopefully some answers that will swing them in the right direction.
    • Total yearly volume - ramping from 2 million now to 16.5 million parts per year within 2 ½ years.
    • 20 different but similar images to be cut. Possibly going to 40 within three + years.
    • Images range from 12" x 14" (305mm x 356mm) at their smallest to 17" x 20" (432mm x 508mm) at the largest. Images are rectangular with radius corners. Some of the images have 1 - 3 simple interior cutouts that must be stripped. Tolerances are ±.060" (±1.53mm).
    • Material is .015" (.381mm) Polyurethane
    • Material typically comes 60" (1,524mm) Wide X .015"(.381mm) X long rolls.
    • Raw material and cut parts have an unlimited shelf life.
    • Cutting and finishing operations will take place in Mexico.

    A numbers break-down looks like this:

  • 16,500,000 parts per year / 20 images = 825,000 parts per image per year.

  • That's 68,750 parts per month of each image.

  • If the factory works 20 days per month they will need to cut a total of 68,750 parts per day.

    Some of the basic needs include:

  • The process must be fast

  • Easy change-overs / set-ups

  • Material yields must be excellent for as little waste as possible.

  • Cut quality must be good. The final assembly process, after the cut, is forgiving of some quality issues arising out of production compromises.

    And here's where the fun starts! What's the best method to cut these parts? Given the large quantity of parts, the large number of different images, and the material to cut, we should look at three different cutting methods. Flatbed diecutting, rotary diecutting and digital diecutting. The production and pricing numbers are ballpark estimates but are close enough to make a good comparison. For the sake of comparison I have also used an average sized part of 16" x 16" (406mm x 406mm) with an 18" (457mm) repeat in both directions.

    Flatbed Diecutting:
    Because of the roll goods, the very wide material width, the quick change over needs, plus the quantity of images and the easy cutting material, I automatically lean toward a steel rule die type set-up cutting against a hard plastic cutting surface. A belt drive system would allow this fairly floppy and stretchable material to feed well into the press and would allow the final parts to flow off the machine for stripping and/or packaging. Multiple layer feeding and cutting are possible, especially against a specialty belt material. By using a CNC controlled belt feed and cutting head system on some type of wide beam press, fantastic yields can be achieved through the use of the entire 60" (1,524mm) width of material. A production rate of 50 impressions per minute is a conservative enough number to use for comparison. A multiple up tool or full bed beam press may improve the numbers. At this rate one machine would need to run three shifts per day twenty days per month in order to keep up with the volume (50 per minute x 60 minutes per hour x 3 shifts or 24hrs = 72,000 parts). Some pressure could be taken off by adding a second machine or experimenting with multiple layer cutting. My best estimate is that this material could be fed and cut in layers of at least 3 deep, reducing the cutting to one machine on only one shift per day.
      CNC / Steel Rule Die / Belt Feed Diecutting: Finished part tolerances ±.015" (±.381mm) ; Typical tooling cost for a one or two on die that moves with the head $200 - $400 USD; Capital expense for press/feeds $125,000 USD; Belt maintenance/etc…. $10,000 USD yearly; Tool life 100,000 + impressions; Tooling change-over time is 20 minutes.

    Rotary Diecutting:
    Because of the large quantity of parts to cut and the possibility of larger volumes after the initial three years, we must take into consideration the fast process of rotary diecutting.

    Both Soft anvil and Hard Anvil cutting are options. In soft anvil you cut against a hard plastic blanket somewhat the same as the belt talked about in the flatbed diecutting above. In soft anvil cutting an inexpensive steel rule type rotary die is used. In hard anvil cutting you cut against a steel cutting cylinder with a solid steel machined rotary die. Both methods achieve very fast running times ranging from 75 to 150 feet per minute on a project/material like this. The major differences are trade-offs between quality and costs of tooling and machinery. Soft anvil cutting will typically produce a less accurate part than hard anvil. Soft anvil will typically be the least expensive route to take.

    Given all the parameters of this project the following information is applicable.
      Soft Anvil Diecutting: Finished part tolerances ±.060"(±1.52mm) ; Typical tooling cost for 4 - 6 on full width rotary die $1,500.00 USD; Capital expense for press/feeds $125,000 USD; Belt maintenance/etc…. $10,000 USD yearly; Tool life 100,000 + impressions; Tooling change-over time is 20 minutes.

      Hard Anvil Diecutting: Finished part tolerances ±.010"(±.254mm) ; Typical tooling cost $25,000.00 USD in 60" width - approx $3,000 - $6,000 USD in 18" width; Capital expense for press/feeds $300,000 USD in 60" width - $75,000 USD in 18" width; Tool life 1,000,000 + impressions; Tooling change-over time is 20 minutes.

    For both types of rotary cutting, a production rate of 100 feet per minute should be a conservative enough number to use. At this rate, on a 60" wide machine, one machine would need to run one shift per day fourteen days per month in order to keep up with the volume (assuming a 16" x 16" part running three across the web at 100 feet per minute x 60 minutes per hour x 1 shift or 8hrs = 96,000 parts). More pressure could be taken off the machine schedule by experimenting with multiple layer cutting.

    In the hard anvil cutting the 60" width becomes a major hang-up due to the cost of the tooling and the cost of the capital equipment. The tool handling also becomes a factor as these monster tools are heavy! The web width could be reduced in both the machinery and tooling as well as the material but some yield compromises would have to be made and the production volume would be cut proportionally. If you had 16,000,000 of the same part this method would certainly be more attractive.

    Digital Diecutting:
    For this project I am including laser cutting, waterjet cutting and knife cutting within the digital diecutting areas of production. All are quite capable of doing a nice job on this material in the material width, within tight tolerances with excellent edge cutting results. With our average part having 70" of cutting (16" x 4 plus an internal cutout), our yearly volume of 16,500,000 parts would have total cutting inches of 1,155,000,000 (yes that's billion) inches. At 200 inches per minute, a good average for digital cutting, there is 96,250 hours of cutting. One year for one shift is 2,080 hours so we would need 16 machines running 3 shifts to keep up with the volume. Cut at four times that speed with a multiple head machine , or common cut as much as possible and you still need alot of machine time to get through the year. The advantage is that there are no tooling costs and set-up time is just about zero. The disadvantage is that the process can't keep up and be cost effective. Once again we run into the large volume fact that nothing beats diecutting for speed!

    All In All:
    Given all the factors discussed, the best route to take is to pursue both the flatbed diecutting and the soft anvil rotary diecutting. There are several manufacturers that would be willing to run real tests on real machinery in order to qualify the processing speeds and the quality of the cut. The other major factor to be tested on press is stripping of the internal waste pieces. Depending on the size and location of these cutouts, the rotary press may have the advantage over the flatbed process. The total cost for this type of testing should be limited to your supplied material, the applicable tooling, and an agreed upon fair hourly rate.

  • Friday, July 23, 2010

    Membrane Switch Cutting

    Written By Mark Batson Baril

    It’s amazing how many things out there involve specialty cutting.

    Do you own a Microwave Oven? - a Treadmill for exercising? - a flat faced calculator? - a machine with a pressure sensitive operation switch? If you do, then chances are you own and use a Flat/Tactile Membrane Switch (or several) everyday! These switches can be used for everything from the simplest of on/off switches on a blood pressure reader to a complicated multilevel/multitasking switching/control system for a printing press.

    It’s hard to say when the technology came into being because some of the simpler connectors/switches have been cut with dies since the 1950’s. When was electricity invented? Membrane switches really took off in the 1980”s when consumers were demanding lower prices and manufacturers had to push for an alternative to the traditional molded/hard printed circuit boards that were so often used as the base for switches on most machines. Their main attributes are, the relatively low price, their relatively quick turn-around production time, plus they look pretty cool!

    Membrane switches are typically made up of six different layers that are all die cut (with Steel Rule Cutting Dies, or laser cut, router cut, matched metal or rotary diecut, etc... depending on the situation) separately and then assembled. The concept is nearly simple in that as with any electrical switch you are trying to create a space between two wires when the circuit is inactive and you are trying to make them touch when you are connecting or making them active.

    The basic layers are;

      # 1 - Graphic Layer - This layer of thin plastic material is what the user sees and touches. It acts as the guide to show you where to push the switch and it sets the tone for the product and it’s operational instructions via the graphics. As with the other layers of a membrane switch, the graphic layer is silk-screen printed. Sometimes the top/graphic layer is diecut as a final pass once everything has been assembled to it, other times it is cut into it’s shape separately. # 2 - Graphic Adhesive Layer - This layer acts as a two sided glue to bond the graphic layer to the top circuit layer. It’s shape can often times be the most intricate in that there can’t be any adhesive that touches the actual switching area. Each of the areas where there is a button or switch must be cut away. # 3 - Top Circuit Layer - This layer acts as the first half of the electrical connection. Silver Ink is printed on polyester to form the electrical paths. Protection from electrical interference from outside the circuit is stopped by printing conductive ink shields, or applying aluminum foil, metallized mylar or copper foil on the top surface of this top circuit. The feeling of the switch is created in this layer as well. You know that great “Popping” feeling you sometimes get when you press one of these switches? That’s when these switch guys have found your “tactile optimum” a.k.a. “feels good point.” The plastic that this layer is made of is put through a process where a heated mold forms little domes at the areas where you will push. When you push down on this dome you get the feeling that you are actually doing something. I hate those switches when you can’t tell that you have pressed anything! # 4 - Spacer Layer - This is the really ingenious layer! Some designer probably made a fortune on this! This layer creates the space between the two circuit layers. The general shape of the outline is cut as well as holes at the points where you want the switch to activate. When you push the dome/top circuit down it pushes through this spacer layer and makes the connection to the bottom circuit, thus completing the electrical circuit. Some of the feeling of the switch is created in this layer as well. When all of these layers are assembled there is air trapped in the “spaces”. The designers will install more cut-aways, called air-tracks, between the various spacer holes. The movement and resistance of this trapped air, when the dome is pushed by the user, can make it harder or easier to push down depending on how many they plan for and how wide they make them. # 5 - Bottom Circuit Layer - This is where the final electrical connection is passed to from the top circuit. The electrical leads from both the top and the bottom circuit pass through a part of the switch called the “TAIL.” This tail is just an extension of the printed plastics that extends beyond the visible part of the graphic layer and goes to the inner workings of the machine you are controlling. # 6 - Rear Adhesive - This double sided glue layer adheres the completed switch to the surface of the machine/circuit board, or whatever is planned for the tail to go into.

    And that’s it! Of course there are about a million variations of how this can go together. Different plastics, metals, rubbers, etc..., can be used to create different electrical properties, feelings for the switch, etc.... . Backlighting can be created, LED’s, resistors, capacitors, even memory chips, can all be added to a switch of this type. Every manufacturer has their own techniques for not only making the switch work but for making it feel like it should for the user, and work for just about any situation.

    The concept is fairly simple yet when you see either a set of dies, prints or even cut parts laid out in front of you, it can look like a fairly complicated puzzle.

    What’s the future in this type of market? Faster and Cheaper! What else! Many manufacturers are actually producing the cuts for membrane switches with lasers. They can produce one switch or short production runs this way with no die costs and no waiting time for the tools. Diemakers hate to hear that! Digital printers now produce the top/bottom circuit and graphic layers direct from the file without having to produce screens/plates/etc.. .

    I’ll be using the membrane switch on my printer now and then switching my computer off to wait for that next inspiring question to hit my desk. Thanks for reading!

    Friday, July 16, 2010

    Make Ready Patch-Up Techniques

    Written By Mark Batson Baril

    Starting Patch-Up at the Right Point During Make-Ready is important, let's explore the basics....

    On a cutting press, with a new job, at the beginning of a make ready - What % of cutting does a cutting pressman start to patch-up the make-ready sheet to get the most mileage from the die?

    This is a tricky question in that having a die last forever and making a profit on a job are often two very different things. Balancing die costs, press time, run length, and the likelihood of repeating the order in the future can become very complex. In most shops an operator is given a set amount of time that he or she should take in order to make the job ready to run. The shorter this given amount of time tends to get the higher the percentage you talk about in your question tends to be. If your press and make-ready system are set-up well, you will not necessarily have to sacrifice die life for a quick make-ready.

    "Spot up" (patch-up) is the process where a pressman uses tapes or other thickness building devices (paper, metals, etc….) to add thickness to areas of the press and the die that tend to be lower than the rest. On a brand new smaller platen type press or a press with a well made die-set used as the cutting surface - the surface that the die rests against and the cutting surface will often be ideal. This means that if you have a well made tool to put in this type of press you will be able to start your patch-up at about 99%, depending on the material being cut. If you have an old beat up machine that never comes down straight twice, and was made with a cutting surface that has more hills and traps than your favorite golf course, then your patch up may start down in the 30-40% range.

    It is for good reason that there has been much talk about setting up your press permanently with a sheet that levels the footprint (takes out the hills and traps), it works and will save you tons of time and add die life as well. By spending this initial set-up time just once on both old presses and new presses you should be able to bring the percentage of nice even cutting up into the 90% range before you need to start your spot up. Again your perfect press situation must now be matched with a perfect tooling situation and profits will soar! Give us a call if you want to find out more about leveling or footprinting your press.

    So to answer your question - there is no real answer. Every press and every press person will have their own intricacies that need to be dealt with. Starting the patching process when you are just starting to see the first cuts penetrate the material is ideal, you just have to work towards getting as much of the image coming through the material at the same time as you can.

    Thursday, July 8, 2010

    Score Bend Testers

    Written By Mark Batson Baril

    I have recently been given a SCORE BEND TESTER by my superior, and have been instructed to start using it. I have been in the industry for 20 years and have had no need for this device. Can someone please tell me how I go about implementing this into my daily routine, and what are the parameters for it's use. I do about 25 - 30 make-readies on Bobst Diecutters a week. Thanks in advance for any help...

    A Score Bend Tester
    Made by Thwing-Albert Instrument Company

    The Score Bend Tester is a device used to test cartons, after they have been die cut, for their strength at the scores. The main result the tester is there to calculate is how much force it takes to open the carton up, from its flat, ready to fill, condition. There are other testers out there that measure the board strength before it is converted into a carton or before a score is formed, but for this question we are focusing on the testing of the scored board only. There are several machines on the market The ones we have researched cost between $6,500.00 and $10,600.00 USD.

    The main purpose of having and using the Score Bend Tester is to control the quality of machined filled boxes. As companies that use automatic machinery in their packaging lines become more sophisticated, they are demanding equal sophistication from their carton producing vendors. Most of these machines find themselves within the Quality Control and/or testing labs of medium to large sized box shops. Typically, parameters are set-up for how much strength it should take to fold open the carton during the machine filling operation. It is then the job of the carton manufacturer to stay within those parameters. The only way to properly test and document what is actually being produced is to run tests on some type of bend tester. As in any statistical process control situation, every production runs' quality control will vary slightly from one to the other. Many companies will take test measurements at the beginning, middle, and end of the run. Each test sampling will usually have at least ten cartons and again will vary depending on the size of the run, the number up the tool is running, the parameters set-up by the final customer, etc...

    We have learned that the testers are used all the way from the sampling process for new cartons, up through the first article inspections done on press, and on to the final production runs. By using the tester as a guide from start to finish, the manufacturer can get controlled information in order to make educated decisions on everything from paper parameters to tooling specifications. To try to insure maximum speeds in their finishing operations, some companies also use the machines to test the flat diecut cartons throughout the run to insure consistency and conformance with their own gluing departments requirements.

    So, those are the basics of what the machine is typically used for. As far as putting it to use as a regular part of your day to day operation, it would seem that this will be a combined effort between you, your quality control department and your customer. The same combined effort holds true if you are using the machine for extra information for your own production improvements. Instead of including your customer in the mix, just include anyone effected by the bend strength of that scored paperboard. Sounds like you have your work "cut-out" for you.

    Many thanks to the Thwing-Albert Instrument Company, who sells 15 - 20 of these machines worldwide per year, for their pictures and candid information.

    Thursday, July 1, 2010

    Cutting Plates for Flatbed Diecutting

    Written By Mark Batson Baril

    Much attention has been placed on cutting rule height tolerances, degree of bevels, type of edge (ground or shaved) and the abilities of the make-ready artist to achieve the best cut. What should one expect from a steel cutting plate? Is the thickness tolerance of the cutting plate equivalent to today’s steel rule height tolerances? How smooth should the surface be? Under normal conditions, how often should parallelism be checked?

    Wait a minute - did someone say artist? In today’s’ world of computer generated this and computer aided that, can there possibly be room for hand/eye/brain type skills anymore?

    As we have talked about several times in other articles, the diecutting and the diemaking functions are completely interrelated in everything from information gathering to the materials and skills used to connect them. The cutting rule and the cutting plate are the very last parts to make the connection in the process. If all goes well this last connection is a smooth one and the perfect cut or "burst through" is achieved. In the perfect world, with many materials, the rule and the cutting plate actually never make contact with one another, as the final particles of material are actually pushed apart or burst through. In reality the connection can sometimes be a very aggressive strike.

    Over the years, as the industry as a whole has strived to improve upon itself; new methods of manufacture, new materials, improvements in die design, etc.... have been applied to the areas that relate to the question posed. The idea being that if we can improve upon each of the individual, yet related areas, the final process and product will get better.

    The areas that apply to this final connection are;

  • The Cutting Press and the quality of its’ parallelism, whether it be across the entire flat surfaces that the die and the cutting plate are applied or around the cylinder that the jacket is applied to. Wear or poor adjustment will effect die and plate life as well as help to produce a poor product. Often times this is where the artist (press person) is asked to turn a school kids’ finger-painting into a Picasso.

  • The Steel Rule Cutting Die and the quality of its components and design. Today’s best ground edge-hardened rule will achieve a consistent height tolerance of ± .0005* (.0127mm). This is unbelievably close to being perfect! The bevel may drift much more than this from side to side yet this will not effect the height. Designed in balancing knives or blocks that distribute the weight of the presses’ stroke across the entire cutting surface (press, die and plate) are tremendously important to maintaining control over height and pressure. Without these balancing knives the press is forced to rock across the cut, defeating any efforts to take advantage of close tolerance presses, rules or plates. Help, call in the artist!

  • The Cutting Plate - Finally getting around to the meat of the question. Given the perfect situation (press, die, press operator, etc..) you should expect the world from a good cutting plate. Billions of impressions? What are the limits? Anyone out there feel like bragging? (resurfacing doesn’t count). The thickness tolerance of today’s best quality cutting plate will be better than or equal to ± .002" (.0508mm). So to answer the second question; NO, the thickness tolerances are not as close in plates as they are in rule height. In fact, in talking with several companies that build the plates, the feeling is that they may be as close as they are going to get to being perfect.

    Many of todays best cutting plates are built per the following;
      1. The initial blank sheet is ground to a rough state that is close to its’ final thickness. 2. The plate is hardened to the desired Rockwell (usually 47-52 RC). 3. The plate is then further finished by hand to its’ close to perfect state (talk about artists!). 4. The plate then goes through its final machine grinding process to create the desired smoothness and final tolerance requirements. The smoothness of the surface is produced in a number of different ways and each manufacturer will claim that their method is best or most cost effective. Everyone’s cutting situation is different and therefore it is hard to say what is smooth enough.

    There are companies that produce the entire plate with no hand work at all. Who’s are better and why? may be a great future subject.

    Parallelism - What is this anyway? Parallelism is the relationship that the top surface of the plate has with the bottom surface of the plate. The best situation is to have a plate who’s’ surfaces have no deviation from parallel (a parallel plate). An un-parallel plate means that your plates’ overall shape is that of a wedge, or perhaps several wedges. Cutting plate parallelism with a deviation of .0015" (.0381mm) is common. Although we have not been able to develope a hard fast answer for how often parallelism should be checked, the basic principals of process control would dictate that each companys’ maintenance routines will vary and will also be constantly changing as newer and better technologies are applied.

    In many cases a soft "under the cutting plate" material help adjust differences in die/cutting plate heights and deviations and take a step towards eliminating the need for press foot printing at all. Expensive on a short term basis, yet one of the cheapest products on the market if looked at from a long term cost standpoint.

    All in all, a great subject that goes to the very core of the diecutting process!

  • Wednesday, June 23, 2010

    Cutting Wire Mesh

    Written By Mark Batson Baril

    This brief and right to the point question came up during the Fall 2000 IADD Association meeting in Vancouver. Should Wire Mesh be die cut or laser cut into unusual shapes?

    Well it just so happens that a recent job required an in-depth investigation of this very subject. The answer, as is almost always the case, lies in the details of the job at hand. The main details to consider with this type of cutting project are these:

    Type of Material and the Tooling - Wire mesh or screen comes in a large variety of different material types. Everything from hard stainless steel to light duty aluminum are included in the category "wire mesh." Thicknesses can range from a micro-wire of only a few thousandths of an inch to mesh used to screen out rocks for landscaping which can be just about as thick as you can imagine.

    When I think of diecutting I automatically think of steel rule dies, forged tools and matched metal tooling. During the research I found that companies are using steel rule dies and forged dies to cut wire mesh, in stainless steel, up to wire diameters of .0625" (1.6mm). This does raise some questions of die-life, or maybe we should call it die-death! Even with some sophisticated coatings, it's tough to find a rule that is much harder than a 60RC and steel rule has the problem that all of it's cutting power is concentrated in the cutting edge. The most common problem with cutting the harder and thicker meshes is not with bending or failing of the rule but is with chipping of the tip of the blade. The steel rule die is great for mesh that is softer than the rule and/or where the quantities are very small. In thicker and harder meshes, no matter the quantity, it really makes no sense at all to use the steel rule or forged die.

    Laser cutting or hard tooling is the answer in these more extreme cases. Long run aluminum jobs can run well on steel rule dies but most stainless and other steels are best left for other types of dies or other types of cutting.

    Matched Metal tooling is a great way to cut most types of wire mesh. Although the cutting edge of a matched metal tool can experience the same chipping a steel rule die does, there is less of this tendency and the cut edge results of the part will tend to be excellent. Depending on the type of mesh to be cut and the type of press you are cutting with, surprisingly good quality and good running speeds can be achieved with hard tooling. The one disadvantage is the high tooling cost and this may be one good reason to go with laser cutting if the quantity you need is low. If it's a long running job, and the equipment is available, using a matched metal tool will result in far fewer headaches than dealing with a steel rule die or the laser cutter. In some situations wire mesh is being used as screening for a medical device or other high end product and good edge quality far outweighs any other consideration. In this case the sky becomes the limit on the method used, no matter the quantity needed. In most of these cases, the matched metal tool will be the best method.

    Quantity to be Cut and Repeat Orders - When we die cut, we are typically dealing with a substantial quantity of parts that need to be produced. The main reason this is true is SPEED. Given a diecuttable product, no other cutting method can beat diecutting for processing speed - and it doesn't matter how many head laser you have! In making the decision on laser vs. die cutting or steel rule die vs. matched metal tool, the total quantity over the course of the life of the project has one heck of a big influence. Laser cutting has the advantage when the material is too thick and/or hard to be cut with a die, and/or the quantity needed is very small - less than 1,000 parts may be a good starting point.

    Combine the quantity factor with the type of material factor, and the edge quality factor, and you will be closing in on the perfect cutting method. In the case we were involved with, the parts were produced using a male/female set-up by a company that stocks thousands of different tools specifically made to cut stainless steel mesh/screen. This company also produces the mesh! Once the contact was made the choice became easy as there was no tooling charge and we were able to reach the quantity minimums with no problem even though the run was very small - only 500 parts total. The quality of the cut was perfect and the question of using an alternative method was ruled out. It won't always be so obvious, especially when the shape is a bit on the unusual side or the material is on the edge of being diecuttable. All-in-all this question is a very open ended one with lots of room for discussion of details. This makes it hard to answer with absolute definition, but will make it an interesting and fun job to tackle when it comes into your shop.

    Thursday, June 17, 2010

    Cutting Punches Defined

    Written By Mark Batson Baril

    A possible lead-in question may look like this.
    As the purchasing agent at medium sized die-cutting house, I am responsible for the purchasing of punches for our dies. It seems that every year our company is purchasing and using more and more punches. It is very important that the punches I purchase are right for our application and are “quality punches”. As there are multiple vendors out there selling punches and there are so many punches available, I would like to know ... what exactly are the most common punches and what makes each a “quality punch”?

    You have come to the right place! There ARE many types and qualities of punches available and your specific applications will constitute what types of punches you want to purchase. First, you need to educate yourself as to the most common punches and then what makes each a “quality punch”...

    The most common punch is the tubular punch. Tube punches are the most economical of all of the punches and are used for the widest range of applications. Slugs cut by a tube punch do not feed thru the punch, but are left in the product being cut with the help of die ejection. A standard tubular punch by definition is a piece of 16 gauge tubing that has a bevel machined on one end to a specific cut size. Tube punch cut sizes span the decimal chart in both millimeter and inch measurements and can be machined into virtually any custom size. A quality tubular punch should have a chamfer on the bottom on both the inside and outside to aid in ease of insertion into the die board. The base size should have a .000" to +.003" tolerance, the cut edge bevel should be virtually free of tool marks and the cut edge should be razor sharp. Springs are available in tube punches to alleviate the need for die ejection. These springs should protrude approximately 1/16” from the cutting edge. A quality tube punch will also be clean of scale, free of burrs, have a case hardening depth of .003" to .005" and a surface hardness of 58-60 Rockwell.

    Similar to the tubular punch is the straight wall punch. Straight wall punches are used for applications with minimum punch space allotment where the base size of a standard tubular punch would be too bog to fit. A straight wall punch has a base size that is only several thousandths of an inch larger than the cut edge. This small difference allows for a slight support bevel for strength. Straight wall punches cause less distortion of cut size in thicker materials. The slugs cut by this punch are left in the product through the use of die ejection or springs and share the tubular punches tolerances and quality guidelines.

    Another common punch is the feed thru punch. Most people will confuse a “feed thru” punch with a “side outlet” punch. In a feed thru punch, the slug exits the punch through the bottom rather than the side as in side outlets. Feed thru punches are used when your application calls for the scrap to be removed from your product rather than being hand stripped at a later time in your manufacturing process. Feed thrus must be run on a bolster plate which supports the die while at the same time allowing the slugs to feed thru where they are vacuumed, blown away, or otherwise disposed of. Feed thrus are constructed from thin wall tubing which is spun or sized then re-machined to your specific cut size. This method assures the proper relief for slug ejection. A quality feed thru’s specs and sizes offered are much the same as a tube and straight wall except that the feed thru’s inside chamfer is minimal, the cut edge should have a slight support bevel on the inside for strength and they do not come with springs.

    A side outlet punch is a punch who’s waste slug feeds through an exhaust chute machined into the side of the punch. Side outlet punches are used when your application calls for scrap to be ejected - as in a feed thru - but this punch does not require the use of a bolster plate. Other than the location of the exhaust hole for the slugs, differences between the feed thru punch and the side outlet are that the side outlet is machined out of a solid piece of steel and it’s use of a shoulder. A side outlet shoulder is defined as the machined area of the punch from the top of the cut edge to just above the exhaust chute.

    The most common type of side outlets are standard and heavy duty. The heavy duty side outlet is used for thicker, heavier, abrasive materials, has an elongated shoulder and often includes a “knurl”. A knurl is a raised portion located at the bottom of a punch - similar in texture to a ratchet handle. It is approximately .005" to .010" larger than the base size of the punch and is .250" wide. The knurl is used to prevent the punch from spinning or becoming misalligned in the routed die board. The standard side outlet is used for easier to cut, medium to thin materials. It has a shorter shoulder than does a heavy duty and does not include a knurl unless specified. Again, a good quality side outlet should be razor sharp, free of tool marks, scale and burrs. It should include a slight support bevel on the inside for strength as well as an undercut which prevents the slug from jamming in the punch before it enters the exhaust chute.

    All punches can be made in a variety of heights - the most common being .937" (23.8mm) and each can be altered to meet your specific application. The life of these punches is effected by the material being cut, the application for which the punch was designed and operator skill level. Typically, a punch should last as long - if not greater than - the rule used in the die.

    Tubular punches, straight wall punches, feed thrus and side outlets may be the most common punches, but they are far from the only ones offered. Custom punches can be manufactured to virtually any shape or size and can be used to produce everything from high tolerance flex circuits to components used in military aircraft to the gasket in your car. Custom punches ... now THAT is another question altogether!!! I hope that you now have a better understanding of some of the more common punches and what makes each a quality punch.

    Sunday, June 13, 2010

    Rotary Die Cutting via Matched Metal

    In a continuing series of Technical Projects that focus upon rotary diecutting and the tools that go with the processes, we must explore the very exciting method of using the male/female die with a small twist. Actually a very large and fast twist may be a bit closer to the mark as this type of cutting system is designed to turn very quickly and very accurately for a growing number of converted products. There seems to be no specific name that has emerged as the common term for this type of cutting. Some common names for the process include; compression cutting, pressure cutting, male female rotary cutting, and rotary pressure cutting - so for the sake of this writing let's call the method the MMRC or (Matched Metal Rotary Cutting).

    Rotary Die Cutting 1

     As a guy with a semi-flat background (careful), I remember seeing one of these tools at the CMM show in Chicago back in the early 1990's. I was amazed. This was probably the most complicated looking monstrosity I had ever seen. It looked to be made in one piece, had to be made to an accuracy that just blew me away, was at least the width of the widest tool I had ever made 60"(1,520mm) and the contraption was round! I mean there were two of them and they were cylinders that matched one another perfectly. Now if I had a hard time getting our flat dies to come up and kiss a flat plate, how in the world could these guys get these things to work. I stood and stared until a salesman explained a little more. Slowly it all began to gel - I was the only sane one in the booth, everyone else had to be nuts! Well, nearly ten years later a good customer of mine has made the decision that this type of MMRC will be the best bet to improve the overall production quality for a particular long run product. I was one of the people that recommended the process to them and in retrospect to that earlier experience in Chicago, the people in that booth were among the savviest converters at the show. The balance of this article will try to explain why.

    Rotary Die Cutting 2

     What is a Matched Metal Rotary Cutting System? Instead of using a crushing cut where a knife like cutter rolls against a solid anvil to make the cut, a shear type cut is made by passing two precisely machined blocks or cutters by or through one another without ever touching anything but the material to be cut. The material is actually squeezed or compressed to the point of bursting without the two parts of the tool ever touching. The two cylinders that make up the tool set both rotate at exactly the same rate in order to create a perfect match to one another through the cut. The two can be brought closer, moved apart, and can even be slid parallel to one another in order to maintain the quality of the cut during the run. The fact that the tools and the system that the tools ride in are so accurate and never actually come in contact with one another creates a unique opportunity for perfect quality and long tool life.What type of products can and should be cut on these tools? The tooling that make this type of operation a success can be expensive. They last for a very long time but usually the cost translates into making products that have a large volume and have specific quality requirements that are hard to accommodate with other methods. Material thickness up to .125" (3.175mm) and no less than .007" (.177mm) can be cut. Some typical materials that convert well include paperboard, high-density plastics, corrugated, recycled paperboard, and specialty coated boards. Folding cartons are a very common product followed by gaskets and then specialty items. What is the quality of product difference? When compared to standard crush cut rotary or flatbed cutting the major product quality improvement issues that make a difference include; less dusting, less slivering, less burring, less nicking - both natural and production oriented, and greater accuracy.

     What are the main production advantages?

    • Feed rates are not limited by the cutting operation! Now there's a statement. These tools will spit out finished product as fast as you can push it through the press. Usually another process like in-line printing or part delivery systems will limit the feet per minute speed of the line.
    • Stripping is done at the cutting stage by either a series of fingers, a through the cylinder collection of waste, or other techniques that remove all waste before the part is delivered to the back side of the die. There is no separate stripping stage and parts are delivered waste and web free. "Stream Stripping" is a term used to describe the waste being removed as a continuous stream as it is pulled into a vacuum tube.
    • Tool life is typically measured in millions of revolutions. Depending on the operator, the material being cut, and the method used to manufacture the dies, cases are reported of solid dies lasting up to 350,000,000 *(yes, that's 350 million) revolutions before needing a sharpening. Flexible dies will typically max out earlier than solid tools somewhere in the range of 4 to 5 million revolutions. This long tool life usually translates into less down-time overall and can translate into lower overall tooling costs when compared to other methods.

    Rotary Die Cutting 3

    What about the tools?

    • The tooling for this type of process is made in both flexible plate and solid machined configurations. The flexible plate tools are usually made via chemical or standard machining or through a combination of the two and are wrapped around a cylinder that stays in the press. The solid machined cylinders are typically made using EDM (Electronic Discharge Machining) or standard direct machining or through a combination of the two.
    • Hardening and finishing techniques for the cutting surfaces can include laser hardening and cladding as well as specialty coatings and platings. All are designed to improve tool life.
    • Web widths can range from 6" to 60" (152.4mm to 1,524mm)
    • Tool diameters can range from 3" to 24" (76.2mm to 610mm)
    • Accuracy is ±.002" (.05mm)
    • Costs for a single matched tool: $1,000.00 to $250,000.00 US That's a huge range and it can vary greatly depending on the image to be cut, the style you choose - flexible or solid, the stripping requirements, the surface finishes, the number of rolls you put in line, etc… Flexible tooling tends to range from $1,000.00 to $3,000.00 US with most narrow web applications falling under the $2,000.00 mark
    • Solid tools can typically be sharpened about five times before they are retired and they can be reworked. Flexible plate tools cannot be sharpened or reworked.
    • Just like male/female cutting in a flat operation, the tolerancing and adjustments made to offsets allow for just about any material to be cut accurately and with ease.
    How is a Crease, Emboss or a Perf produced?
    The MMRC technique will only cut through material. Just like with a pair of scissors or a steel rule bridger, it's tough to make a kiss cut or a dent with a male/female tool. When a crease or an emboss or a perf need to be produced a crushing operation must be added. A blade like or crease like male is added with a hard anvil counter on the opposite cylinder. Because the upper and lower cylinders are both being machined, reverse scores and reverse cut-scores can be created as easily as the standards. These can be incorporated into the tool that does the perimeter cut or can be incorporated into a second set of die cylinders that fall before the final cut stage. Separating the stages has the advantage of creating a long life tool and a shorter life tool that can be worked on individually.

    Are there specialty machines that are needed to run this type of tooling?
    There are many companies that make presses to accommodate rotary cutting. This type of tooling and process (MMRC) can be used in many of them. In general the die manufacturers that make this type of tooling will do their best to build a tool that will work in your press.
    Finishing Up
    Everyone has their own take on techniques used in our industry. What the future will hold for MMRC will most likely be embroiled in what happens to run lengths, corporate consolidations/product consolidations, and mechanization of other attached packaging processes. For the time being this technique has a growing number of markets that it plays very well to. The cheaper flexible and magnetically mounted tooling is being pushed hard right now by a couple of tool manufacturers. Although this type of flexible tooling will never replace the need for the more expensive solid tools it will more than likely allow more converters to use this type of cutting technique on a more regular basis. As more rotary converters discover the benefits, for those special jobs, the technique will flourish. I predict that this will lead to an explosive market over the next twenty years where once again our productivity as converters advances by leaps and bounds.As lessons go, this ten year process of becoming familiar with MMRC has been too slow but has taught me to listen a little longer and a little harder to everyone I meet. I hope you too find a product that can use this process to your full advantage, and that the IADD has once again started you off in the right direction.*At printing of this article the production was closing in on 400,000,000 revolutions (not parts). This solid machined tool was made by Bernal Technologies and is cutting .018" Poly coated SBS. Wow! Not all solid tools will last this long. It all comes down to materials, machines, and operators.

    Support for this writing came from several sources including:

      Marc Voorhees - Bermaxx LLC / Bernal TechnologiesMarc Love - Atlas Chem-MillingJim Redd - XynatechRon Brenwall of Maxim InternationalPhotos courtesy of Bermaxx LLC / Bernal Technologies.
    Thank-you very much!

    Thursday, June 3, 2010

    PMC Dies and Diecutting

    Written By Mark Batson Baril

    PMC Die Cutters and Cutting Tools

    The question came to us the other day on whether we worked with companies that dealt in PMC Cutting tools and could we suggest a source. The first part of the question led to the first part of our answer - What the heck is a PMC cutting tool?

    Because of my “bag over head” knowledge in this area, and because others may also be in the dark on this one, the mission is clear. So here we go, trying to shed a bit of light on what they are and how they are used.

    PMC turned out not to be a type of technology - it turned out to be a brand/manufacturer name. PMC (Printing Machinery Corp.) developed its first hollow die label cutting machine in 1940. The idea was to create a machine that could cut a variety of printed and non-printed materials accurately and quickly. What was developed was a machine that uses a cutting tool that acts as a high speed feed through punch. The machine pushes a large stack of materials up through the tool and the finished parts are ejected out the back of the machine, the tool, and finally the bolster plate. I have found that there are four major players in this type of machinery/cutting system - PMC, BUSCH, BLUMER, and VIJUK.

    The machines are designed to feed sheeted materials that have been stacked to a height of up to 4" (102mm). Press bed sizes are usually small, staying in most cases less than 20" x 20" (508mm x 508mm). The machines can cycle up to 20 times per minute. If the part you are cutting is only .005" (.127mm) thick it means you can cut a whole mess of parts in not a whole lot of time. The manufacturers claim that on certain materials on certain machines the cut sheet rate per hour can easily exceed 1,000,000. Yes that’s one million sheets! Just to compare, a fully automatic Bobst Carton cutter on steroids may hit the mid teens (that’s thousands).

    So why haven’t some of us been exposed to this type of cutter/tooling in the past? It may be that the machines are primarily used to cut very high volume common products with dies that are not steel rule dies. Plus they are used to cut some fairly usual but specialized products that many of us shy away from.

    The list of products and services that work well on this type of machine include the following:
    • Labels
    • Wrappers
    • Envelope Blanks
    • Note Pads
    • Credit Cards
    • Identification Tags
    • Deckle-edge postcards
    • Game Cards
    • Paint Chips
    • Luggage and Price Tags
    • Coasters
    • Placemats
    • 3-way Booklet Trimming
    • Round Cornering

    Some of the more common materials that are cut on these machines include:
    • Embossed Paper
    • Unevenly Printed Label papers
    • Plastic
    • Foil
    • Mylar
    • Paperboard

    Stacks of material are loaded outside the die cutting area and are automatically jogged and lined up. The stacks are held on all four sides throughout the die cutting operation which makes the possibility of a very accurate cut quite good. There are material shuttles that allow one stack to be automatically loaded while another one is being cut. This creates very little time in which the machine is not actually cutting. Parts do not have to be ejected back out through the front of the die and so the machine can constantly act towards cutting rather than cutting and ejecting. The tooling only makes contact with the cutting plate during the last cut of the stack. This means that tools last longer as the only friction they see is the material they are cutting.

    The Tools:
    Dies for this type of machine are quite simply feed through specialty punches. They are typically made in two ways. They are forged dies made from pre-ground rule that is bent and formed and then welded at the joint, or they are machined (usually wire cut) dies that are cut from a single block of steel. The height will vary from job to job and machine to machine but usually ranges from 1 1/2" (38mm) to upwards of 4" (102mm). The thickness will vary depending on the application and will have a taper that runs from small at the cutting edge to large at the base. Because the die will feed the finished parts through the center, all the taper will run to the outside of the tool. Support tabs, mounting brackets, and stripping knives are all items that can be built-in to help the operator speed the process and help the tool survive the incredible stress of the impression. Standard bolster plates are used within the machine to create a space for the finished parts to pass through the back of the die. On unusual shapes or large repeat run jobs, a custom bolster plate can be made for a perfect match.

    Thanks for all the help from Brian at Stewart Industries (PMC Worldwide) and Lynn at Progressive Service Die Co..