Archive for September, 2013

Speaking at the KCOHG Conference

Saturday, September 21st, 2013

Glow badge

Two weeks ago I had the privileged to speak at the inaugural Kansas City Open Hardware Group (kcohg.org) Conference. The event was set up and hosted by CCCKC (c3kc.org) and the Kauffman Foundation (kauffman.org). I made up some glow badges for the event (seen above) and, in the spirit of the event, released them under CC over at our Thingiverse page. Head over there to get the design files as well as the details of the components and assembly!

Also if you want to check out my hastily prepared talk check out the video below. I actually start up at about 18:00:

 

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This is why we never leave the laser cutter unattended…

Wednesday, September 4th, 2013

Burnt stock

So last week we had a little bit of a fire in the small cutter. What you see above is the bottom side of some stock that I was cutting that ignited. Luckily I was watching it so it only was burning for a few seconds before it was caught and the fire was handled. The fire was entirely under the material being cut so it went undetected for a little bit (in fact the top side of the above sheet is warped but not burnt in the slightest compared to the bottom).

Damaged Vector Grid

The vector grid delaminated a bit so it's toast and the connector for the rotary attachment got a little charred. The Delrin slides at the back of the machine that the downdraft ports the Z-axis tray ride on got more than a little melty as well (pic below). After closer inspection it looks like the dusk accumulated in the back of the machine ignited as well.

Melty Parts

Fortunately nothing above the stuff being cut was effected and the optics were just fine. The flames were easily controlled with the squirt bottle I keep handy around the cutters and we've got a proper CO2 extinguisher if things get really bad. I didn't have a lot of material in the catch tray to act as fuel, but enough that a flare up turned into a little fire. We've got an extra vector grid on hand so we were back up and cutting withing 2 hours after checking everything out. Thankfully with a quick call to Epilog and I can get replacements for everything damaged as well.

It looks like either the different masking material of the frosted acrylic I was cutting or insufficient air flow at the active cooling tube might be the culprit. The compressor was reading 30 psi, but much less than that was getting to the actual head. I tightened up a leaky fitting after the dryer that helped but I'll be giving that entire system the once over this week. Either way, I'm glad that even after 4 years of running the cutters I still walk over and check them every couple of minutes when it's operating and always make sure someone's watching them when I can't because this flare up could have turned into a full on fire rather quickly.