Die cutting (web)
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Die cutting is the process of using a die to shear webs of low-strength materials, such as rubber, fiber, foil, cloth, paper, corrugated fiberboard, paperboard, plastics, pressure-sensitive adhesive tapes, foam and sheet metal. In the metalworking and leather industries, the process is known as clicking and the machine may be referred to as a clicking machine. When a dinking die or dinking machine is used, the process is known as dinking. Commonly produced items using this process include gaskets, labels, corrugated boxes, and envelopes.
Die cutting started as a process of cutting leather for the shoe industry in the mid-19th century. It is now sophisticated enough to cut through just one layer of a laminate, so it is now used on labels, stamps, and other stickers; this type of die cutting is known as kiss cutting.
Die cutting can be done on either flatbed or rotary presses. Rotary die cutting is often done inline with printing. The primary difference between rotary die cutting and flatbed die cutting is that the flatbed is not as fast but the tools are cheaper. This process lends itself to smaller production runs where it is not as easy to absorb the added cost of a rotary die.
Rotary die cutting
Rotary die cutting is die cutting using a cylindrical die on a rotary press. A long sheet or web of material will be fed through the press into an area known as a "station" which holds a rotary tool that will cut out shapes, make perforations or creases, or even cut the sheet or web into smaller parts. A series of gears will force the die to rotate at the same speed as the rest of the press, ensuring that any cuts the die makes line up with the printing on the material. The machines used for this process can incorporate multiple "stations" that die cut a particular shape in the material. In each of these stations lie one or more of these geared tools or printing cylinders, and some machines use automatic eye registration to make sure the cuts and / or printing are lined up with one another when higher tolerances are required.
Dies used in rotary die cutting are either solid engraved dies, adjustable dies, or magnetic plate tooling. Engraved dies have a much higher tolerance and are machined out of a solid steel bar normally made out of tool steel. Adjustable dies have removable blades that can be easily replaced with other blades, either due to wear or to cut a different material, while magnetic plate tooling has a cylinder that has magnets placed in it, and an engraved metal plate is attached or wrapped around the base cylinder holding onto it by the force of the magnets.
Dinking uses special dies called dinking dies, or hollow cutters. The edges of the dies are usually beveled about 20° and sharpened. The material is punched through into a wood or soft metal block in order to not dull the edges. The die may be pressed into the material with a hammer or a mechanical press.
See also for more
- Davis, Joseph R. (1992), ASM materials engineering dictionary, ASM International, p. 116, ISBN 978-0-87170-447-4.
- Allen, Frederick James (1922), The shoe industry, Holt, p. 144.
- Berins, Michael L.; Society of the Plastics Industry (1991), SPI plastics engineering handbook of the Society of the Plastics Industry, Inc (5th ed.), Springer, p. 688, ISBN 978-0-412-99181-3.
- Fundamentals of Manufacturing By Philip D. Rufe 2001
- American Machinists’ Handbook and Dictionary of Shop Terms by Fred H. Colvin and Frank A Stanley 1914
- Degarmo, Black & Kohser 2003, p. 428.