Discover how digital cutting systems work and how various models differ.
By Lori Leaman
Roll-fed (or drum-fed) cutters are used with flexible roll materials that are pulled or fed through the machine (Figure 2). These systems use either friction- or sprocket-feed technology to transport substrates. Materials on friction-feed cutters move backward and forward via grit rollers, which are located underneath the media and serve as the driving mechanism. Pinch rollers located above the material lower onto the substrate and hold it in place. The cutting head moves back and forth across the media on an axis that is perpendicular to the feed direction of the material. On sprocket-fed systems, sprocket-like wheels grip and pull the material via prepunched holes in the material's edge. Roll-fed systems are suitable for cutting PVC stock, reflective films, and other substrates used for decals and signage applications.
Cost and speed are two main draws to friction-based, roll-fed cutters. Today, a sign shop can purchase a 50-in. friction cutter for approximately $5000 and expect speeds as high as 44 in./sec. Friction-based cutters also accept a wide range of media, punched or unpunched, in a variety of widths. Because the friction cutter accepts punched material, many shops find that they are able to use up scrap material from previous jobs, thereby eliminating waste mate-rial and the costs associated with it.
Friction-fed cutters offer many advantages, but there are considerations to keep in mind. Sean Childs, product manager at Gerber Scientific Products, says a friction cutter's accuracy is good, but does not measure up to the accuracy offered by sprocket-fed cutters. Additionally, because friction-fed cutters rely on user skill for manually loading material, jobs can be ruined easily when user skill is not up to par. Friction-fed cutters also do not allow for unattended operation.
Childs explains that sprocket-fed systems, while slower (top linear speed is 36 in./sec), offer better image alignment than friction-fed systems because the sprockets lock the material in place, preventing it from shifting position. He points out that the high degree of accuracy is especially important in jobs that involve layering.
"If you're producing a three-color sign, you grab three different colors of vinyl, cut them out, and then layer them," Childs says. "If you do a shadow, a block letter, and some highlights on top, you want to make sure that everything lines up. You don't want to be repositioning pieces of vinyl during application."
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