Finish grinding process for rotary die cutting machine

DETAILED DESCRIPTION The invention relates to a manufacturing process for rotary die cutting machines wherein tolerances may be predictably achieved.
The process is more specifically directed to a cylinder rotary die cutter to provide extended die life.
More particularly, the invention relates to a finish grinding process for the cylinders of a rotary die cutting machine.
Rotary die cutting machines for cutting or perforating webs of material are run at high speeds and provide for a die cylinder to contact the web of material between an adjacent, usually counter-revolving, anvil cylinder.
The smaller the manufacturing tolerances for rotary die cutters, the more uniformly the cutters will cut the web of product being fed to them.
With high speed cutters heat build-up can create uneven expansion of the cyliners.
It is improtant to maintain the operating tolerance of the cylinders relative to each other and avoid the heat expansion problems.
In this regard, by reducing the cylinder total indicated runout (TIR), the die life and running speeds of the die and anvil cylinders can be increased.
By reducing the TIR, the interference between the die cylinder and anvil cylinder will be reduced thereby minimizing die deterioration and heat buildup so that the cutting quality on the web of material may be consistently achieved over a longer period of time.
Conventional manufacturing procedures for rotary die cutters require the use of high precision bearings in order to achieve a high predictable precision of the completed die cutter.
This requires using Class 3 bearing, which provide the best predictable cylinder gap tolerance achieveable down to about 0.
0006 inches.
This tolerance error is simply the result of the use of the Class 3 bearings alone.
The present invention provides a manufacturing process that will allow the use of less precise Class 2 or 4 bearings but will achieve a much higher predictable cylinder gap tolerance of 0.
00008 inches and better.
This is seven and one-half times more precise then the prior art use of Class 3 bearings