Gaskets are indispensable for containing liquids or gases within mechanical, hydraulic, and pneumatic assemblies. Gasket materials range from the traditional resin-coated paper, cork, and rubber materials like Neoprene and Viton® to newer liquid or gel gasket compounds such as RTV silicone and Hylomar®.

This particular application involves cutting Viton rubber gaskets in a prototype and limited production environment. Laser cutting offers several benefits in this instance; the first being that the laser’s non-contact cutting method eliminates material deformation caused by mechanical cutters. The second advantage is the laser’s flexibility – cutting a different gasket shape is as easy as loading another CAD drawing into the control system.

Marking a Test Matrix

With the rapid increase in new materials created by advances in Materials Science, engineers and operators on the shop floor are often tasked to optimize marking parameters when new materials are incorporated into existing product lines. The key is to quickly hone in on the correct parameters in a short amount of time with a minimal amount of wasted product.

A useful tool for testing unfamiliar materials is a test matrix. This is simply an array of objects that represent the type of object you plan to mark – filled or unfilled text, polylines (circles, squares, lines), or even 1D and 2D barcodes. To narrow down the best Power and Velocity values, set each row of objects to a different Power value and set each column to different mark speeds (Velocity). A 10×10 grid provides 100 combinations of Power versus Velocity with just a single mark. The photo shows a test mark of filled squares where Resolution values ranging from 100 to 1000 are plotted against Power values ranging from 10 to 100% of full laser output.

Cutting Mylar Film

Mylar® is a versatile polyester/PET film used in hundreds, if not thousands, of products worldwide. Among other properties, Mylar is easily laminated and printed, lending itself to widespread use in the packaging and converting industry. The clarity of Mylar film makes it an excellent choice in applications as disparate as fresh food packaging to crime scene fingerprint retrieval.

This CO₂ laser application involves cutting two-mil (0.002”) thick adhesive-backed Mylar along with its five-mil (0.005”) thick backing material. Our XY cutting setup consisted of a 2.5” positive meniscus lens, which provides a 0.004” (100 micron) spot with a 0.07” depth of focus, and coaxial air assist at 10 PSI. Using a power of 60 watts, we achieved maximum cut speeds of 1100 inches per minute.