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.
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;
Thanks Guys!
Please contact Cut Smart if you would like more information on this subject.
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