The Wonders of Medium Tack Masking
Something that most people don’t realize, though is obvious in hindsight, is that when you burn something, the material goes from a solid to a semi-solid, particulate or vapor phase which tends to stick to everything! CNC lasers have essentially the same problem as your BBQ except the stuff coming off our bed doesn’t taste all that good.
Lasers essentially vaporize material, whether it’s wood, acrylic or even powder coatings off aluminium! For some materials, this vapor is very light or so insignificant that it’s barely noticeable such as when we are engraving anodized aluminium plaques or business cards but other times like a denser material like oak or ironwood of any significant thickness… you end up with smoke which can damage your source material and if not cleaned-up, the laser itself as build-up on the lens or mirror can cause a rather expensive crack! This is where masking is vitally important along with an awesome extraction system.
What we tend to do with wood is actually apply a mask on both the front and back side of the board, even with a vacuum table, powerful extraction and air compressor (gas kit) hooked-up to the Trotec Speedy 400 flexx, you still get stuff that seems to craw along the edges onto the surface of the cut material. What masking – medium tack is best – tends to do is provide a ready surface for that debris to sit or stain which is great… as it’s just peeled off after the engraving / cutting process which leaves a finished project requiring little to no sanding. Our CO2 laser source was tested at 110 watts, tack paper doesn’t stand a chance so it won’t affect cutting speeds.
The only time masking is a bit of a pain is when you have small details or parts, think of a wooden plaque with a poem engraved into the wood… all those “o” and “d” and “e” will have an insignificant amount of tack paper which takes just as long to remove as the job takes to engrave sometimes but the advantage is you can’t really sand those parts anyhow. Customers benefit greatly from the use of tack paper because it saves them money, removing a sheet of sticky paper is far faster here at CNCROi.com than spot-sanding a board or using cleaning fluids to remove solidified resins.