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Ed Maloney
12-30-2016, 10:03 AM
I have found that when laser cutting yellow acrylic it tends to flame-up much more than other colors. Anyone have an idea of why that is?

Ed

John Blazy
12-30-2016, 1:20 PM
I got several fires this past month lasering out snowflakes for Christmas gifts. I usually get the fires when cutting close to an edge, where lots of air flow is, but lots of detail cutting in close proximity will build up gas pockets underneath.

Not sure about yellow acrylic though. Never used it.

I keep a water bottle right next to the laser now, and know exactly where my fire extinguisher is. Main thing is to pause the laser when hitting the restroom - otherwise never leave sight of when running. Thank god my laser is right in my office.

Ed Maloney
12-30-2016, 2:04 PM
In this case it's not detailed at all. Just long straight cuts. I turn down very detailed jobs in acrylic now given the situation that you point out John. Had a really bad fire a couple of years ago (doing snowflake Christmas ornaments) and I am an arms length away from the laser. Got distracted for maybe a minute or two and when I glanced over the damn sheet was on fire. Took me a few days to clean it up and it's still running.

Mike Null
12-31-2016, 8:07 AM
Ed
Do you have air assist on your machine. If not you will find it helps a lot.

Some colors do tend to flare up more than others. You might experiment with your settings, particularly hertz.

Ed Maloney
12-31-2016, 9:52 AM
Mike - Yes I am using air assist. I'll play around with some of the yellow scraps and see.

Kev Williams
12-31-2016, 1:12 PM
If I'm cutting anything that might catch fire, or when engraving wood and leather, I'll put an fan in the cabinet and aim it at the engraving area This blows the smoke sideways fast, which keeps a lot of the soot off the leather and wood, and keeps fires from starting. Makes for a smoky cabinet but the blower gets it all out in 30 seconds or so.

The air assist on my Triumph is just the diaphragm pump and wide-open 1/4" tube (no nozzle) aimed down where the laser fires. This makes soot WORSE, which is why I use a fan, but it does keep plex and paper from catching fire...