Slitting, Sheeting and Cutting
"Type 10" styles of Tyvek® can be slit and cut into sheets on most commercial equipment using conventional paper-cutting techniques. However, the inherent toughness of Tyvek® requires that all cutting parts be kept clean and sharp, with true, well-supported, nick-free edges. A sharp, slightly rounded edge gives longer service than a pointed edge for crush cutting, but a sharp edge is preferred for other slitting methods.
When it is necessary to convert styles that have no antistat coating, such as styles 1059B and 1073B, the use of conductive "tinsel" or ionized air produced by an electrostatic generator or a radiation bar will usually reduce the buildup of static to an acceptable level. Antistatic agents or aerosol sprays should not be used on Tyvek® that will be used in food packaging or pharmaceutical applications.
Multiple roll sheeting (4-6 rolls) works well with Tyvek® and is preferred for the lightweight styles less than 2.2 oz/yd2 (74.6 g/m2).
To minimize cutting problems:
- Replace straight-edged blades with blades that have a wavy or serrated edge.
- Use blades coated with Teflon® TFE fluorocarbon or lubricated with a nonstaining silicone spray.
- Reduce the cutting stroke from 1.5 inches (3.8 cm) down to 1 in. (2.5 cm).
- Operate at 1800 rpm instead of 3600 rpm.
- Paper is more abrasive than Tyvek® and will dull blades faster. This can cause problems when cutting Tyvek® after paper.
Sheets of Tyvek® can be die-cut using either steel rule (sharp edge) or male/female dies. Since the inherent toughness of the material requires that male/female dies be manufactured to close tolerances, steel rule dies are usually preferred. Tyvek® fibers must be completely cut; dies must be kept in good condition, with sharp, true, nick-free, well-supported edges. Dull dies cause cut edges to curl. On steel rule or high dies, slight internal relief helps reduce heat buildup. When working with closed dies, the strength of Tyvek® will probably require use of a side cutter or chisel edge to speed up release and prevent die and product damage. Dies should be hardened to Rockwell C 50-60 to extend their life.
Keep lift heights below 3 in. (7.6 cm) when die-cutting to avoid oversizing top blanks by edge compression as the die comes down. Use of a center-die pressure cylinder can help deaerate and compact the lift, and minimize slippage.