by Jenny Knodell, IQS Editor
Think back to the last time you made Christmas cookies with your grandmother. You know, those sugar cookies shaped like candy canes, Christmas trees and snowflakes that are topped in icing and colored sugar. They are a big part of my family’s holiday traditions, and I looked forward to making them every year. Creating those complex shapes was no big deal, even for a little girl. They came out perfect every time, thanks to cookie cutters, those metal cut-out shapes that ensured a high degree of accuracy. Without them, the candy canes would be indistinguishable from the trees. Now, take the idea of a cookie cutter, make it automated and take it from your grandmother’s kitchen and into a manufacturing environment…what do you have? Die cutting—the industrial process that takes 2 dimensional sheets of material and forms them into complex shapes using a metal saw, diamond tipped saw or, more recently, laser beams.
Like making cookies, the dies (cookie cutters) replace hand cutting with scissors, which is painstaking, slow and produces irregular parts out of plastic, rubber, magnets, cardboard, paper, fabric, leather, wood and even metal (the dough). The products made from die cutting must be flat, and include small, common commercial products like greeting cards and keys, industrial products like gaskets and shipping boxes, on up to massive metal parts that are used as ship components. Believe it or not, this is how puzzles are made! A photograph on thick cardboard material is placed into the die cutting machine, where blades or lasers cut it into many interlocking, predefined pieces using CNC or CAD/CAM systems. Because die cut machines are industrial manufacturing machinery, they tend to be very strong, and often cut many layers of material to produce many identical products at once.
Jigsaw Puzzle Die
There are two main methods of die cutting—rotary die cutting and steel rule die cutting. Rotary die cutting, which is also called gasket die cutting because it’s the main method for producing gaskets, cut flat pieces of material by forcing it between sharp blades on a cylindrical die and a hard cylindrical anvil on a rotary press. It is a continuous process that unwinds the material sheets and pushes it through 2 rolling calendar dies. This process offers high repeatability, with tolerances as close as .02″ because the material is continuously fed instead of hand fed, which prevents error. Steel rule dies, or clicker dies, are die cutting machines that feed the material in batches instead of continuously. It is considered the most common approach, and can produce the most complex and intricate designs. These methods are older, and with the introduction of laser cutting, are slowly phasing out of popularity.
Plastic die cutting photo courtesy of Thrust Industries.
Other die cutting specifications include the method of cutting: kiss cutting or crush cutting, each producing different results. Crush cutting cuts all the way though the entire material sheet, making a clean cut. Most products are formed this way. Some adhesive-backed products like stickers are made via die cutting, and are composed of two layers. Kiss cutting is a way to cut only the top layer, leaving the adhesive backing whole. Besides stickers, foam adhesives and tape are made this way.
Photo courtesy of Design Converting, Inc.