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mark lankton
08-25-2006, 8:37 AM
As everyone who has stumbled onto this site I've found the questions and answers very helpful. Thanks.
Has anyone vector cut fused quartz? I have a sample coming that's .078 thick. I'm told it cuts at 3000F. Anyone know the temp. that a laser generates? Most of my work has been with wood (myrtlewood in particular)
Thanks in advance.

Mark Lankton

Joe Pelonio
08-25-2006, 9:20 AM
Mark,

I don't think the melting temperature helps here. The laser is pulsing, in order to keep from overheating the areas around the cut line. The beam at a certain wattage may reach 3000 degrees, but with the pulsing still may not melt it. Also, the laser is not really melting but more like vaporizing.

Quartz is harder than glass, so while I'm just guessing here it probably acts like glass, the beam would engrave it but not cut it.

mark lankton
08-25-2006, 9:24 AM
Joe,

Makes sense. Thanks for the reply. When I get the sample I'll try it and post what results I get. Maybe it'll score and snap?

Mark

Rodne Gold
08-25-2006, 11:04 AM
It is one of the glass materials that does laser cut well
Heres some info
http://www.synrad.com/search_apps/materials/Glass_Quartz.htm
http://www.synrad.com/search_apps/application_briefs/20-1.htm
Dunno bout your specific thickness tho.

mark lankton
08-25-2006, 7:55 PM
Rodne,

Thanks for the website. Good info. Sounds like cutting may be a possiblity.
This is a great site (sawmill creek) by the way. I usually check it out twice a day and often get useful information. When I learn more I hope to contribute and not just soak up tips.

Dave Jones
08-25-2006, 8:26 PM
Keep in mind that the example in the Synrad site was .030" thick and was cut with 50 watts at 20"/minute. Thats 3 seconds per inch. That is very slow. Your sample is 2-1/2 times thicker, so it's possible that your laser might not go slow enough.

But it can't hurt to experiment.

mark lankton
09-05-2006, 10:20 AM
I finally received a sample of fused quartz (.078" thick) and I was able to cut it. It was slow but worked for the purpose I needed. I'm not claiming these are the best settings, only that they did work. The sample I had was small (and expensive) so I didn't do a lot of trials. I'm running a Pinnacle M-series 40 watt laser w/ air assist. It took two passes. The run time was around 1 1/8" per minute. Slow but doable. I did get a slight "raising" along the cut edges and a couple of test pieces had some small chips.

The settings I used are:

600dpi
speed=.2
power=100

If anyone has a better take on this I'd appreciate it.

Thanks, Mark

Mitchell Andrus
09-05-2006, 1:06 PM
Given this slow speed, why do this with a laser? Is the accuracy important? Could the same result be obtained with a special blade in a <gasp> scroll saw? What's the project?

I love my laser, but sometimes it's a bit like holding a hammer and thinking everything is a nail.

Mitch

mark lankton
09-05-2006, 8:05 PM
Mitch,

Yes, accuracy as well as repeatability was critical. Sorry to be vague, it was a test for a project that is "in development" as they say. I agree that sometimes technology can blind us to the simple and easier ways of doing something.

Mark

Rob Bosworth
09-06-2006, 10:55 AM
Have you run into any crazing of the fused quartz? We used to drill a bunch of holes in fused quarts windows. They drilled great. Then a few days later they would develop crazing around the edges of the laser cuts. We ended up having to run them through an annealing oven to avoid the crazing or micro-cracking.

mark lankton
09-06-2006, 7:34 PM
Rob,

So far I haven't noticed any micro cracks though I did have a couple of chips on two as I snapped them out. Also, had some raising of the cut edges.

Mark

Rodne Gold
09-07-2006, 1:03 AM
We find chamfering or scraping edges of materials that are prone to stress cracking to be very effective in stopping this (done after its laser processed) We use a small countersinking bit to "ream" the top and bottom of holes (by hand) and this seems to work well.
IE we try to reduce the "sharp" edge that the cracks propogate from and in doing so , we remove a little of the heat affected zone material.
Obviously this doesnt work with everything and the ability to chamfer depends on the material and the cuts.