Progressive Cutting Tools

Written By Mark Batson Baril

What is a "Progressive Cutting Tool" and should everyone be using this type of tooling in their diecutting operation?

There are many different types of tooling for many different specialty applications that involve diecutting. Progressive cutting tools typically fall into the category of male/female or matched metal tooling. They can also include steel rule die or milled punch shapes as well. For the sake of this answer we are talking about a single tool where all of the component cuts are made within this one tool. What this type of tool does so well is cut very complicated shapes from difficult to process materials (AKA - the stuff nobody wants to work with). The shape will often include interior knock-out, slits, embosses, and unusually shaped perimeter cuts. Because the tool would be very difficult to build as a one stage, one strike does it all type of tool, the final shape is accomplished through a series of steps that the material progresses through. As to whether or not everyone should be using this type of tooling - the answer lies in the complexity of the shapes you tend to cut and whether or not you have the type of machinery, designers, and tool makers to run a tool like this.

The Machine:
The typical machine that runs a progressive tool is a punch press or a flatbed platen type press with some type of accurate incremental feed system. The key to having all your options open during the tool design phase is to have a machine that has an open bottom or clearing bolster plate, an open back or side(s) for clearing waste and feeding, and a feed system that is tied directly to the motion of the machine. For moderately to large tolerances (± .062" 1.57mm) the feed system must hold the material accurately the entire time it is in motion and while it is stopped. In this type of tool there is no registration while in the tool except for side guides. For more accurate alignment throughout the process (±.005" .127mm) the feed unit must hold and place the material accurately and then just as the impression is made the feed unit must allow the material to move freely and settle on the pre-punched locating holes (pilots). Having a finely tuned feed unit with a material release is critical to the entire process.

The Tool:
The typical tool layout will have a series of stages where various cuts take place. The natural stages occur in this progression -

1. The material enters the tool and the first impression cuts a series of two or four pilot holes that will allow for exact registration during the balance of the cuts. The more piloting holes you have the more accurate the product will be. The pilot holes make the location by sliding onto or being centered by a tapered male pin in each stage of the tool. Other part related holes, shapes or slits can also be cut at this point. 2. During the second, third, or fourth stage(s), other cuts, embosses, etc…, can be made all in perfect registration using the pilot holes. The real beauty of the cuts made during the several progressive stages of cutting is that extremely unusual or complex shapes can be made via multiple cuts at one image. 3. During the last stage, the final perimeter cut is made and the final finished part is typically blanked through the tool into the part collector below. Because of the way the stages have been planned, the final part will have no chance of nicks or uncut areas in any of the normal joint areas related to a steel rule die.

During all the cutting, the material web is never asked to carry a part that has been pushed back into the web after a cut as is often the case with a steel rule or combo male-female/steel rule die. Each cut stage strips the waste away and only during the final cut does the web become weakened by the missing part. Because of this, the press can be run at maximum speed and accurate parts can be delivered waste free very quickly given just about any material type or part shape.

All in all this type of tool should win the "REALLY COOL TOOL AWARD".
This is one of those great areas to explore with just the right project and I hope that one day you have the need to buy, help plan, or run one in your shop too.

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.

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.

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.

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.

Score Bend Testers

Written By Mark Batson Baril

THE QUESTION:
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.

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.

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..

Calculating Die Cutting Tonnage Continued...

Let’s Get Really Technical:
 
A couple of us have actually talked about developing an on-line tonnage calculating website. It would be comprised of a database that held values and asked questions like; Strength values (Tensile) for most common materials (A), Shear strength values for several processes/rule types/ejection, etc…(B), Number of inches being cut (C), Thickness of the material (D). A X B X C X D = Tons 2,000

In fact, this is exactly how many software stress analysis programs work. They take a set of very obvious variables and make a simple calculation based on these (and other) numbers. It gives you a very consistent way of looking at every project you take on. Right or wrong, the answer is a base number to start with, and that is what we have gathered is the trick to determining proper starting tonnage numbers. Once you have this standard formula in place and trust that it will give you that base number, you can then depend on it and translate it to work in different machinery on your shop floor. Perhaps you have a string of ten punch presses and they all cut a little different. One is hydraulic, one is pneumatic, one is mechanical off a simple small cam while another throws off a giant flywheel that was welded back together by Uncle Joe a few years back. They all cut differently but they all have a factor you can use as a multiplier against that base number we just calculated out. It’s beautifully simple really, it just takes some time to develop and work out in your own shop, on your own equipment. Once you have that number, everyone can plan around the equipment you have vs. the projects you have with more confidence.

So then the formula may look like this;
(A X B X C X D) F = Tons (Where F is a press factor based on experience and/or a manufacturers guidelines.) 2,000 Putting this into a real life situation may look something like this; I have a ten up steel rule die cutting and creasing .018” paperboard. There are 1,000 total inches of cutting, creasing, stripping, support knives etc… I am using modern ejection materials. I am cutting on a platen style press.
17000(A) X 1(B) X 1,000(C) X .018(D) X 1(F) = 153 Tons. 2,000
Simple Formulas from above; C/6.5 = Tons (1,000 / 6.5 = 153.8 Tons) or (C X 400) / 2,000 = Tons (1,000 X 400) / 2,000 = 200 Tons

Both formulas work and give us a range that is safe and a good starting point.

Now Let’s Get Really Simple:
 
What seems to happen with all this fancy calculating in real world situations is that the base theory gets boiled down to simple formulas that work for similar situations. Most of us deal in very similar tooling and materials everyday and having a very fast and simple way of coming up with a safe base number is natural. If you are always working in paperboard in about the same caliper, taking the total periphery and dividing by a single proven number is a fantastic way to approach tonnage calculating. The same goes for plastic, steel, leather, or anything else you cut on a regular basis.

So, this article is not going to give a catch-all formula for determining tonnage for all materials on all press types, with all tools, because there are too many factors involved and nobody would ever use it in real life. What we can do is offer a base calculation where you plug in your own numbers based on experience. Your own situation will provide the best formula for you.

That base calculation would look like this;
Total Periphery to Convert X Material Factor / 2,000 = Tons Needed

Developing a living chart of MATERIAL FACTORS will then be the key to making this work in your business. We’ve been using paperboard a good deal in our discussions and it seems that a starting point for a folding carton manufacturer on a Flatbed style press would be a MATERIAL FACTOR of 300. The heavier gauge the material is the bigger the Material Factor. (1,000 Inches X 300) / 2,000 = 150 Tons Keep in mind that if your cutting process changes, maybe it’s as simple as going to a harder rubber or steeper bevel rule, you will have to use a multiplier to compensate for this change.

There is no trick of the trade in calculating the tonnage you need for a project but as you develop a more and more sophisticated list of materials and how they process on your equipment, you will have an estimating and production tool that will help you predict with greater accuracy how well a job will run, where it should run, how many up it can run, and whether or not it will run at all. You will have a leg up on the competition that is still shooting from the hip and this will really put the pressure on them…..

We’d like to thank all of the operators out there that are trying to improve their production techniques and came to The TECHTEAM with their questions!

Case Study: Snow Shoe Cutting

Written By Mark Batson Baril

On this particular project we were asked to visit, and so we did. The following is a gathering of facts as seen from the manufacturers viewpoint...

A few quotes gathered during that visit;
"We dread the busy season this year. We make snow shoes and one of our major operations includes diecutting. We currently have twenty-eight different shoe models and each model averages five different cut shapes. These five parts will often be of at least three different materials all of which are fairly tough to cut multiple layer synthetics. We produced approx. 5,000 of each model during last year. About every two to three years the models change and so we must at least partially re-tool. Some of the models have an overlap of parts allowing us to combine diecutting runs. We currently use clicker/forged dies, steel rule dies, and specialty machined dies."

"Our problems include the following:"

• Sales of our product are increasing fast. They are also unpredictable in regards to which model will sell best and what the actual quantities will be.
• We are running two clicker type presses full time on two shifts and can barely keep pace. We plan to go to a third shift this year during the busy season.
• We believe that the diecut parts of our product will become obsolete within 5 - 10 years.
• Prototypes are needed by R & D, quickly and accurately from our CAD files. We have no way of doing this well.
• Yield is critical because our materials are so expensive. All our material comes in rolls. They vary from 36" (915mm) wide to 60"(1,524mm) wide. Currently we must slit and sheet everything to size and then make our cuts, not always enjoying a no-waste situation.

"The question is - Is there a better way, and what is it?"

A Better Way:

After gathering some facts from the outside, we have put together the following possibilities followed by a recommendation.

Put on the third shift and continue as you have been. This has the advantage of simplicity, very little capital cost and no additional space needed for production. Your operators are already trained and new ones will be easy to bring up to speed. Disadvantages include having to hire more people, no yield improvements, and no prototype abilities. The costs of doing this may prove to be the highest of all of the solutions mentioned here.

Put in another clicker press and keep the production to just two shifts. A good clicker type press can be purchased for under $8,000.00 USD and will save you a lot of money in the cost of actually setting up a temporary third shift. This doesn’t solve all the problems but it may be a good cheap fix for this year. Long term this still has the yield problem nipping at your heals. As we all know in the diecutting business, material is where the money can be made or lost!

Choose several of your common large quantity parts and have a diecutting manufacturer produce these parts for you. You can still control the materials and the timing for deliveries while someone else absorbs the cost of the machinery needed to do the job quickly and efficiently. You may be surprised at the overall cost of the purchased parts compared to your actual costs of cutting them yourself. The current manufacturer of your materials may even be able to provide you with this service and with today’s quick turn-around times, your unpredictable sales volumes will not be a problem. Your company can continue to produce the specialty and low volume parts in-house while having the stress of the high volume parts passed on to someone else.

Plan to purchase a new type of press. The perfect type of press for your situation would be a traversing head press with a belt delivery system that feeds from a roll. These presses can also be purchased with computer controls that allow for a best yield for material based on your CAD file. The head can turn in any direction as it travels in order to get the perfect nest and the fastest cut. These machines also have the advantage of being able to store into memory each part or job and to be able to recall this information at the touch of a button. Between this technology and tooling matched to it, set-up times would be very short. You would, more than likely, be able to use most of your current supply of dies. Cost would be around $ 80,000 USD. You would be able to eliminate your slitting and sheeting operations and should gain enough time to be able to reduce your full time cutting staff from four people to two. This combined with material gains may make it a very logical choice. The gains would outweigh the costs over the course of a few years, and should beat the obsolescence of your product by a wide margin. You may even be able to cut products for other companies in your area. The only area it misses is the prototypes!

We talked about waterjet cutting, CNC routing, and other computer driven cutting machines at our meeting. The advantages they all have are that they would enable you to produce prototypes, would allow you to get a great yield from the material, and would eliminate any tooling costs associated with your constantly changing models. They would also eliminate the slitting and sheeting of materials. The two big disadvantages they have are that they are slow compared to punching parts out with tooling, and they all are very expensive to purchase, possibly reaching past the $125,000 mark without blinking an eye. Typical running speeds on any of these machines will be between 30 and 200 inches per minute depending on the material and how intricate the cuts are, where as a tool with 30 to 200 inches of cutting surface can make an impression many times during that same minute.

From this group of five possible solutions it seems as though the traversing head press purchase is the most logical with prototypes being cut by an outside vendor. A closer look may uncover that a combination of the above suggestions may be your best choice.

Our recommendation at this point would be to gather together and take a closer look at your costs, especially those costs associated with wasted materials. Is it really possible to gain a significant amount of money by cutting materials to a better yield? How much time and money will you really save by not having to convert the rolls before they are die cut? What does your labor really cost you over the course of a year and does it make sense to try and reduce the labor cost? What are the sales predictions for the next five years and have they been accurate over the past five years?

The final conclusion set this company on a course that continued some production in-house while developing an outside source that cut finished parts and prototypes. A great solution for a semi-complicated situation.

Diecutting Food

Written by Mark Batson Baril

SO - YOU WANT TO DIE CUT WHAT? It never stops amazing me how many different products are cut with dies and specialty cutting processes. Most recently I have been reminded that there are many companies out there that need to cut food as part of their production. Sometimes it's just slitting, slicing or chopping and sometimes a manufacturer will want to produce a product in a shape that cannot be extruded or made in a mold. In this case, we as die cutters, die makers, and specialty cutters are called upon to step up to the oven and take a shot at the unusual. Years ago I built some tooling that was to be used for cutting brownies into that typical rectangular shape brownies come in. Instead of slitting the shapes in two directions after the sheet of goods was baked, the manufacturer wanted to cut the entire sheet of cooked goods in one shot as it passed down the line. They wanted a very uniform size and wanted to trim the baked edges off so everyone got exactly the same thing. As it happened, we made no effort to look into any type of government regulations or standard industry practices that would help us figure out what materials to use. We had a couple of meetings, used a bit of common sense, and came up with a very basic steel rule die that used solid stainless steel blades and a plastic base that was approved for medical applications by a US government agency (good enough for medical it must be good enough for food, right?). Ejection was handled with a center hole in each cavity that allowed a stainless stripper plate to be activated from the back of the tool. Everything was washable, would resist rusting, corroding, and no part of the tool could flake away and become part of the food. We built a great tool and everything worked well. In retrospect, we probably should have made the tool with no base and welded everything together so it would have been easier to wash, or better yet we should have passed the whole project onto someone that really knew the business. Still the question remains with me today, did we build tooling that met the standards?

All around the world governments have set-up standards that food manufacturers must adhere to. Deep down, I think this is what we all worry about when we get into making tools, or processing foods, and rightly so. In the US we have the FDA (Food and Drug Administration) that tells us how to produce things when it comes to foods - they police it too… In Europe there are as many regulators as there are countries and yet with the growing closeness of European countries an entity called The European Commission is taking more control of these matters. In China, the Ministry of Health plays a big part in who does what and how. From Ministries of Health to Food Inspection Agencies around the world, everyone has got to follow some sort of rule when they process foods. There are even cooperative agreements set-up between countries/agencies to help manage the production of food that will be imported/exported between them. All in all it can become a very complex task to take on compliance with these government regulations.

"I'm just a diemaker" you say! Well we've got to start somewhere and I'll tell you that it's quite a relief to find that a government agency (the FDA is easiest for me to access and has a pretty decent web site) uses at least a little common sense when it comes to the equipment used for cutting food. Here are some excerpts from:
The FDA Code of Federal Regulations- Title 21, Volume 2 - TITLE 21 -- Food And Drugs - Chapter I -- Food And Drug Administration, Department Of Health And Human Services - Part 110--Current Good Manufacturing Practice In Manufacturing, Packing, Or Holding Human Food.

Sec. 110.20 Plant and grounds.
(a) General maintenance. Buildings, fixtures, and other physical facilities of the plant shall be maintained in a sanitary condition and shall be kept in repair sufficient to prevent food from becoming adulterated within the meaning of the act. Cleaning and sanitizing of utensils and equipment shall be conducted in a manner that protects against contamination of food, food-contact surfaces, or food-packaging materials.

Sec. 110.40 Equipment and utensils - (This Includes the Dies and Presses)
(a) All plant equipment and utensils shall be so designed and of such material and workmanship as to be adequately cleanable, and shall be properly maintained. The design, construction, and use of equipment and utensils shall preclude the adulteration of food with lubricants, fuel, metal fragments, contaminated water, or any other contaminants. All equipment should be so installed and maintained as to facilitate the cleaning of the equipment and of all adjacent spaces. Food-contact surfaces shall be corrosion-resistant when in contact with food. They shall be made of nontoxic materials and designed to withstand the environment of their intended use and the action of food, and, if applicable, cleaning compounds and sanitizing agents. Food-contact surfaces shall be maintained to protect food from being contaminated by any source, including unlawful indirect food additives.
(b) Seams on food-contact surfaces shall be smoothly bonded or maintained so as to minimize accumulation of food particles, dirt, and organic matter and thus minimize the opportunity for growth of microorganisms.

Sec. 110.80 Processes and controls.
(10) Mechanical manufacturing steps such as washing, peeling, trimming, cutting, sorting and inspecting, mashing, dewatering, cooling, shredding, extruding, drying, whipping, defatting, and forming shall be performed so as to protect food against contamination. Compliance with this requirement may be accomplished by providing adequate physical protection of food from contaminants that may drip, drain, or be drawn into the food. Protection may be provided by adequate cleaning and sanitizing of all food-contact surfaces, and by using time and temperature controls at and between each manufacturing step.

Wow - Did you actually read all that? Those are three minor sections of a seventeen page document that outlines the basics you need to know to cut food or to build tooling that will cut food in the US. You'll have to go to another document for some of the definitions of some of those sections. All in all though I must say that most of it is common sense and quite achievable within most diemaking shops and with many die cutting machines. If you are not in the US you may find that the rules to follow are more stringent or less stringent. Putting it all together as one neat, consistently reproducible manufacturing process is the trick. There are consultants as well as people from within your various government agencies that can help in setting up and maintaining a proper process.

So to answer the question of whether or not we built tooling that met the standards - I would say yes we did. (That's a load off my mind!) In fact, if the company that was using the tooling was following the rules, they would have had a person in charge of making sure we were in compliance and if there had been a problem, we would have heard about it. And if they were somehow out of line with this way of thinking, I'm sure the Food Police would have caught up with the whole bunch of us.

Of course none of this covers the very related area of diecutting items that will come into direct contact with foods. Labels, packaging, tags, etc….. all fall into this category and although the manufacturing of these will carry somewhat the same rules and regulations that actual food cutting does, the big added factor to watch out for is the type of material that you are incorporating. Papers, plastics, inks, coatings, glues, etc….. are all controlled under many government agencies.

Good luck and I hope this gets anyone interested in die cutting food, or making tools for the same, started in the right direction and further away from that anxious feeling that comes with dealing with government regulations.

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

Medical Device Tooling For Diecutting

Written By Mark Batson Baril

More than once in the last month, the question has been put forth as to how to produce a good steel rule type die that will be used to cut a disposable medical device. There are many different types of medical devices. The ones we are talking about here may be produced in clean room conditions but are more likely required to be produced in clean areas that have very little contamination allowed. These medical devices may be used internally and almost always come in contact with the body. The parts may be sterilized after they are produced but they are expected to pick up as few extra particles as possible during all phases of production. In some cases the tooling is used in production of bio medical devices/products where it is important to the product to be exposed to as little extra material as possible during processing.

The make-up of the tooling seems quite simple until you start to research the methods and materials needed to produce a die that will fit the following set of conditions:

-Will not rust even if exposed to alcohol, water, and other nasty chemicals (we consider water to be nasty because it causes rust)

-Will not flake or shed material, including steel, wood, rubber, plastic, etc…

-Will enable cleaning of the tool to remove glues, hydrogels, foam residues, etc…

-Will be accurate, reproducible, long lasting, fast to produce, and of course inexpensive

-Will not crack or loosen during production runs.

Considering all of the above - the tool should be made of some type of plastic base with stainless steel rule/punches and a non-shedding ejection material. Here's what we found in each case:

Base Materials:
Acrylic is the clear plastic base material of choice for many diemakers. The main reasons are that it is clear, readily available, and it cuts very well on a laser. The main drawbacks for medical are that it is not FDA*(US Food and Drug Administration) approved and it cracks easily under the stress of diecutting. This material is not a great choice for medical dies.

Polycarbonate (common trade name is Lexan) is another common choice. It is clear, easily found, and resists cracking very well. It is 30 times as strong as Acrylic. It's two main drawbacks for medical dies are that it cannot be cut on the laser (thin polycarbonate can be cut on the laser, while ½" to ¾" prove to be almost impossible) and it is not FDA approved. If your tools must be clear (see through) this is probably you best choice.

High Density Polyethylene, Low Density Polyethylene, ABS, PVC and PETG are also commonly available base materials that are tempting to use. None of them cut well on the laser and none of them are approved for use by the FDA. We see no advantage to considering any of them unless you need to think about electrical properties and static.

UHMW-PE (Ultra High Molecular Weight Polyethylene), Nylon, and Delrin are all readily available, and are FDA approved. None of them cut well on the laser but we highly recommend all of them for use in die bases. They are very impact resistant, chemical resistant, machine well, and come in White which really looks great when you are making a medical die. This is your best choice.

The problem with this best choice for base materials is that the laser is not a great way to work the material to the shape you want. The material can be jigged well and can be machined well which leaves us with quite a few production options. Most die shops will have a jig saw at their disposal and can produce their tool as it was done before lasers. Most also have some type of drill press or milling machine that will allow for simple shapes like holes to be cut to receive punches, washer sets, and specialty punches. All of us have at our reach the ability to outsource a specialty base like this to a machine shop equipped with CNC machining capabilities. The base can be machined in two pieces or more, in order to build just about any shape imagined. Offsets can be built in to receive rule or punches and the tool is built without bridges. Every project will be different, but there are very few limits that can be placed on a die when we combine the methods that are available to accurately machine plastics. Keep in mind one of the advantages of the old methods of producing steel rule dies (non-laser) is that the kerf is very consistent from top to bottom. There are typically no voids or pockets left to collect any of the fluids that the tooling may see for medical production clean-up and the top and bottom only grabbing we see from a laser kerf is replaced by a tight non-moving match of rule to base.

When it comes right down to it, if you can use a tool that has no base material, you will be best off. Forged tooling type dies are a great choice in this area.

Blade Material/Punches:
All the rules that we commonly use for steel rule dies will rust. They have coatings (usually oils) that stop them from rusting in the box, but once they're in the die and the oil wears off, they are going to rust, especially if you wash them with water. We have one customer who washes their tooling by putting it in a bucket of water (FDA Approved of course) and then scrubs it down. The other thing that we need to avoid in the medical field is delivering a tool that has oil on it to start with.

So there are a couple of choices to make. One is to produce the tool using a rust resistant steel, the other is to plate or cover the regular tool steel with a rust resistant coating.

Stainless Steel is the best thing to use for both rule and any type of punch. It is expensive, hard to find anyone who wants to work with, takes a long time to get through the machining process, and is hard to bend and work with once it is heat treated. 400 series stainless can be machined well, is heat treatable so it can be brought to the hardness needed for big volume diecutting, and it is still rust resistant. We accomplish everything we need except quick turn-around times for tooling and it is not cheap to make. 300 series is more common for diemakers to use in that it does not have to be heat treated, and is bendable. It is not as hard as a 400 series but it will withstand many impressions in many materials and is actually more rust resistant than the 400 series. 303 and 304 are more common than 316 and are use commonly for cutting medical products. The 316 series steel designation shows up as "the best" steel to use for medical devices and this is true for implanted devices that will be in the body for more than 30 days. For standard cutting the 303 and 304 work well.

Coatings are a great way to go if you have the right coating. The one major drawback that all coatings can have is possible flaking or wearing off. Especially in the medical field where non-contamination is key, the concerns with coating steel used for cutting is real. However, if you can create the correct coating the results can be no worse than the normal wearing off of steel you get from the typical steel rule, punch, or even stainless steel rule. We have found that Electroless Nickel Coating with an after coating heat treating, works well. This process adds .0002 (.00508mm) of rust resistant material that wears at close to the same rate as the steel it is covering. Relative to having the parts made in stainless it can be much less expensive, and it is a fairly common and fast process to get through. Make sure you deal with a company that can not only specify what they are doing for you, but can also provide a certificate that says that's what they did. Coating shops are a dime a dozen. Good ones are worth their weight in …. Electroless Nickel.

Ejection Materials:
Typical materials we use in the steel rule die industry for ejection will naturally wear and start to shed material after a certain number of impressions. That number will vary with every project and every press being used. Some of the tricks used for ejection for medical include the following:


-Don't use it! Yes, creating holes in the tool or some other way of ejecting the part is the best way to avoid contamination.

-Use Waterjet cutting to produce the rubber shape. This eliminates that first round of debris you may have from pressing the rubber into the tool or using another type of cutter to cut the rubber.

-Use a top coating or some type of sheet plastic material. This layer stays on top of the rubber and not only helps the top surface of the rubber last longer but also stops any debris from touching the product. I have seen regular old fiberglass reinforced packing tape work well for this.

-Use springs or even flat top ejection plates were you can within the tool. Make these out of stainless or have them coated.

-Consult with your rubber supplier on their best type of material that will give you the push you need and the lack of shedding that your customer requires.


Putting it All Together:

The one last key ingredient to make part of your system of making your medical dies work well is to train the final user to replace their tools on a regular basis. Base materials will wear and get contaminated. Steel used for cutting will wear, flake, and stop cutting well. Ejection will eventually stop ejecting and start to break down. Finding that breaking point in the tools productive life is probably best left to the operator. Telling the operator that a breaking point exists is up to the tool maker.

Tools for the medical industry can be tough to manufacture. I have met many die makers that tend to turn down this type of work. I have also met a few that like this type of work because it tends to pay very well and can be rewarding from a technical standpoint. I have found that it is very possible to meet all the parameters found in the first part of this article except - fast and inexpensive. I Hope this passes on a few tricks of the trade and helps you to develop new ideas on producing or buying better tools.

* The FDA recognizes certain materials as being OK to use for contact with food products during production. Although there probably is a special designation for base materials for cutting tools that the FDA sees as OK for producing medical devices, we have not been able to find it yet. We have always gone with the assumption that if it works for food it works for medical dies. Most medical manufacturers we have dealt with seem to run on the same assumption.

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