Rotary or Flat Bed Die Cuts
The main method or standard means of die cutting involves the use of metal dies to give paper or substrate products specific shapes or designs that cannot be accomplished by a straight cut on a web press or a guillotine cutter. By using knife-edge cutting blades formed into a pattern or die, a machine presses the die into the material to produce the desired shape. Almost any shape can be created and applied to a diverse array of raw materials. Labels, envelopes, folders, cartons, and documents are only a few of the many printed products that can be die cut for added functionality.
Web presses often have a rotary die unit that is utilized for die cutting paper and label stocks. Although there are limitations on the types of dies and the paper selections that can be provided, rotary die cutting serves as an effective method for longer run quantities of printed materials requiring some type of die cut area.
Single sheet products require the use of a flat bed die and a flat bed cutting press to die cut the shape into the paper stock. The speed of this process is slower than a web press, but it does provide die cutting capabilities to a wider variety of paper stocks and printed products.
Typical samples of various die cuts from steel blades:
Cut Sheets or Integrated Products
A second method of die cutting, which has been developed in recent years, is called laser engraving. By using a computer-controlled beam of light to cut through the material, text and images can be accurately reproduced on a variety of paper stocks. By using a laser, manufacturers can provide an exceptionally high quality, well-detailed and fine-lined reproduction of intricate art and images or corporate logos.
The laser can create die cuts that have cut away areas which are very small in size, unlike a rotary or flat bed die cut which encounters difficulty in having a die made for small cut areas and further, has difficulty in stripping away the paper from the small cut out areas. A laser engraved die cut can be created to reproduce a 800 dpi (dots per inch) image allowing for a cut impression with a significant amount of clarity and definition.
Samples of Laser Engraved Die Cuts
Perf Cutting or Perforating
An alternative to die cutting that is sometimes used is perf cutting or perforating. This process does not fully trim the desired materials away from the original shape, but instead creates a cut out area that remains in place. Perforating is used when a desired section is to be removed from the document, but not immediately. The intent is to have the perforated area remain on the document until it is removed later by the consumer or a secondary process. Perforating blades, which contain cut and uncut areas, are constructed into a die pattern. The cut area of the blade strikes through the material while the uncut segment or tie of the blade does not cut the paper, enabling the perforated area to remain attached to the document until it is to be removed.
Preparation for Die Cuts or Perforations
When determining if a material should be die cut or perforated, the following points should be considered:
- The thickness and firmness of the material.
- The stretch and elasticity or spring back of the material.
- The coatings or laminated components of the material.
In order to provide a high quality (“clean”) die cut or perforation, the following factors should be considered:
- The type of material to be die cut or perforated.
- The type of die and blades used for the cut or perforation.
- The cutting surface (either hardened steel or compressible substrate) on which the material will lay when the die or perf blades are forced into the material.
- The machine that is accomplishing the die cut or perforation.
Samples of Perforations
Print materials can contain multiple perforations enabling a variety of tasks to be accomplished for additional processing of the document.