Laser Cutting Painted Materials

The next time you’re wandering the aisles in stores like Sears, Lowes, or the Home Depot take a close look at those stainless steel kitchen appliances. Chances are what you’re looking at is a faux stainless steel surface.  Pre-painted materials cost much less than true stainless steel making the finished product available to homeowners on a budget at an attractive price point. They carry names such as monochromatic stainless steel, black stainless steel, clean steel and finger print resistant stainless steel; just to name a few examples.  For these and other reasons, painted materials are growing in popularity.  OK so what are the challenges associated with laser processing these types of materials?

Pre-painted material generally comes in a thickness of anywhere from 18-24 gauge and is a common material in the home appliance, industrial refrigeration, and similar industries.  Those hoping to do business in this realm should certainly become familiar with the dos and don’ts of laser cutting material coated with paint.  While such materials may sometimes come with a PVC film, my experience is that the coating is often insufficiently tacky to adhere to the painted surface.  The likely result is instability during laser processing with, again, bubbling and/or melting likely to occur. To further compound the situation, painted material coated with film is generally a lesser grade and not conducive to pre-melting. It is therefore recommended to have your steel supplier provide laser-quality film. You may also elect to peel the film off then begin cutting taking care not to damage the painted surface.

I’ve found fiber lasers to be the best choice when processing painted materials. However it’s important to keep in mind that cutting such material at a rate that is too fast or too hot will likely create a burn mark on the surface of the material near the edge. Some lighter colors are more susceptible to showing burn marks than others and typically very light colors, especially bright white are not candidates for Fiber lasers. It is also possible that some colors may not cut at all due to how the wavelength of a fiber optic laser reacts to those colors.  It is always recommended to take the time to experiment and dial-in the optimum cutting condition before beginning a long run of laser cut parts.