Cutting molded acetal copolymer tubing, using a Firestar 100W laser, produced a clean cut edge.

Acetal copolymer, also called polyacetal or polyoxymethylene (POM) is an engineered thermoplastic polymer that features high wear resistance, high flexure fatigue strength, and excellent dimensional stability. Acetal copolymer is available in a pure, unfilled form or can be modified by special additives including glass fibers, colorants, or lubricants. Acetal products are easily created by injection, compression, or blow molding, by extrusion, or by rotational casting. Acetal copolymers are also available in medical and food grades for manufactured products sold to the medical or food processing industries.

This application called for cutting molded acetal copolymer tubing with a wall thickness of 0.041” (1.0 mm). Our beam delivery consisted of a Firestar 100 watt laser focused through a 2.5” positive meniscus lens, providing a 0.004” spot with a 0.07” depth of focus. Clean, dry air at 20 PSI was delivered through the nozzle (coaxially with the beam) for the gas assist.

Part motion was achieved using a rotary stage so that the tubing was rotated under the point of focus at a linear cut speed of 122 inches per minute (IPM). Although acetal vaporizes completely, leaving a cleanly cut edge, properly placed fume extraction prevents any vapor from being re-deposited on or near the cut edge.