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Need Help!i want to cut the plexiglas but i new to laser cutter machine!

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NicoleHip
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Joined: Thu Oct 01, 2015 3:46 pm

Need Help!i want to cut the plexiglas but i new to laser cutter machine!

Postby NicoleHip » Tue Oct 25, 2016 2:21 pm

Hello, everyone!

I'm new to the laser engraving world .. my company makes QR code tags, and engraving on the anondized aluminum is no problem. But I'm trying to cut a jig out of plexiglas, and it's not really cutting through very well. I'm hoping someone can help me, maybe tell me if I'm doing something wrong.

We have a VLS 6.60. The plexiglas is 1/8" thick. I set up the cutting lines in illustrator, .07 points line thickness, rgb red, and hit print. The print manager sets the power etc for the material, and in this case set it at power 100%, speed 2.7%. It is cutting the lines in the plexiglas, but very slowly ... I think I'd have to run the print job maybe 8 or 10 times to cut all the way through, and that seems like too many.

Can anyone help me? ... I'm mostly wondering if I'm missing something really simple or obvious.

Thank you sooo much!

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BiVecyMisy
Posts: 10
Joined: Fri Oct 02, 2015 1:43 pm

Re: Need Help!i want to cut the plexiglas but i new to laser cutter machine!

Postby BiVecyMisy » Wed Oct 26, 2016 9:52 am

3 mm acrylic plexi should cut with a beautiful polished edge at 7 mm / sec and 30 watts with either a 2.5" or 4" lens, that is a slow, quality, cut. You'll have to work back from what your machine is to get those numbers. You also want to vector cut lines, which are infinitely thin, just paths. 1/ is it focused properly 2/ not too much assist gas, just enough to keep the lens clear 3/ are all the optics clear and aligned. FWIW I always always always experiment with a small test job on a spare square inch or 25 mm square of the material in question, if it cuts the test job nicely, you're good to go.. http://www.exeter-laser.co.uk/media/EL-test01.dxf (28kb dxf)

Wayne Rees
Posts: 14
Joined: Mon Jun 20, 2016 5:34 pm

Re: Need Help!i want to cut the plexiglas but i new to laser cutter machine!

Postby Wayne Rees » Wed Oct 26, 2016 8:40 pm

Plexiglass is a brand of acrylic, that should cut easily at the setting you describe, are you sure its not polycarbonate or Pet-g

NicoleHip
Posts: 11
Joined: Thu Oct 01, 2015 3:46 pm

Re: Need Help!i want to cut the plexiglas but i new to laser cutter machine!

Postby NicoleHip » Thu Oct 27, 2016 11:45 am

Thank you! My problem (remember I am a total newbie) had to do with reading the RGB color from Illustrator. Because of the code that creates the illustrator file, it always opens as CYMK, and I have to convert it. Somehow converting the stroke on the lines to RGB red didn't take in the printing unless I hit "preview" before saving. ? Well, now I know. :-)

But now I have another problem. I did cut through the plexiglas once I solved the color problem, but the cutting left melted residue on the engraving table. How can I get it off without damaging the engraving table? Now I know to raise any acrylic before cutting, but sadly I'm almost learning as I go, and from my mistakes ... if only I can keep the machine safe from my mistakes until I know enough not to make them ...

Thanks!

felyapoops
Posts: 3
Joined: Wed Jul 22, 2015 12:01 am

Re: Need Help!i want to cut the plexiglas but i new to laser cutter machine!

Postby felyapoops » Fri Oct 28, 2016 9:30 am

if it's lumps gentle application of a flat screwdriver blade.
if its condensate use isopropyl alcohol and a rag

NicoleHip
Posts: 11
Joined: Thu Oct 01, 2015 3:46 pm

Re: Need Help!i want to cut the plexiglas but i new to laser cutter machine!

Postby NicoleHip » Mon Oct 31, 2016 2:02 pm

Oh, thank you so much! I love this laser, but I'm so worried about making a mistake with it, and then this happens. :|

HarveyGon
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Joined: Mon Jul 20, 2015 10:52 am

Re: Need Help!i want to cut the plexiglas but i new to laser cutter machine!

Postby HarveyGon » Tue Nov 01, 2016 12:38 pm

I once read some advice on a laser forum, where the contributor (Rodney Gold - credit where credit's due!) suggested using strategically placed 10mm blocks of acrylic (plexiglass) to raise the plexiglass sheet off the bed. I have followed this tip for years (albeit slightly modified) I now use 20mm long sticks of acrylic (plexiglass) (6mm x 6mm) let into a 25mm square to hold up the sheet. This gives no reflection. Sometimes it may stick a little and if your pieces are too small for your spacing of the little acrylic stands, they may fall out and get burned by the laser beam. However, that can be overcome by splitting the outline and opening a .5mm space in a convenient spot so the part may be snapped
out afterwards. I don't usually bother to focus below the surface of the material unless it is close to the maximum thickness I am able to cut.

NicoleHip
Posts: 11
Joined: Thu Oct 01, 2015 3:46 pm

Re: Need Help!i want to cut the plexiglas but i new to laser cutter machine!

Postby NicoleHip » Thu Nov 03, 2016 12:25 am

Oh, that's a really good idea. I hope we won't be cutting much acrylic ... the smell once the engraver was opened was unbearable. It's just for jigs, so maybe a few more, and then we should be done! But your tip is a good one, and I'll make sure to raise the sheet up somehow ... maybe not on plexiglas strips, but on something. I spent 3 hours today cleaning the engraving table with alchohol and lots of elbow grease ... the residue came off, but it's interesting, the aluminum surface is discolored where the residue was. Pretty cool, actually.

alufnino
Posts: 5
Joined: Sun Sep 27, 2015 1:57 am

Re: Need Help!i want to cut the plexiglas but i new to laser cutter machine!

Postby alufnino » Thu Nov 03, 2016 12:25 am

NicoleHip wrote:Oh, that's a really good idea. I hope we won't be cutting much acrylic ... the smell once the engraver was opened was unbearable. It's just for jigs, so maybe a few more, and then we should be done! But your tip is a good one, and I'll make sure to raise the sheet up somehow ... maybe not on plexiglas strips, but on something. I spent 3 hours today cleaning the engraving table with alchohol and lots of elbow grease ... the residue came off, but it's interesting, the aluminum surface is discolored where the residue was. Pretty cool, actually.

What wattage is your tube????

NicoleHip
Posts: 11
Joined: Thu Oct 01, 2015 3:46 pm

Re: Need Help!i want to cut the plexiglas but i new to laser cutter machine!

Postby NicoleHip » Thu Nov 03, 2016 12:25 am

alufnino wrote:
NicoleHip wrote:Oh, that's a really good idea. I hope we won't be cutting much acrylic ... the smell once the engraver was opened was unbearable. It's just for jigs, so maybe a few more, and then we should be done! But your tip is a good one, and I'll make sure to raise the sheet up somehow ... maybe not on plexiglas strips, but on something. I spent 3 hours today cleaning the engraving table with alchohol and lots of elbow grease ... the residue came off, but it's interesting, the aluminum surface is discolored where the residue was. Pretty cool, actually.

What wattage is your tube????

It's a 30W, but it actually cut through the plexiglas no problem once it read the lines as vectors. When I changed the red in illustrator to RGB 255-0-0, it didn't change (even if I hit "Save") unless I also checked the "preview" box. Which I don't understand (it's a software quirk), but now I know and can do that each time. And when it was correctly interpreted as vectors, it cut RIGHT through the plexiglas - so much so that the acrylic residue melted on the engraving table. So this morning I (and my very kind boss) spent a bit of time and elbow grease using rubbing alcohol getting off the acrylic residue. It's smooth now, but oddly stained (lighter) where the acrylic had melted in. It's difficult having an expensive machine with a steep learning curve and very little training ... but man do I love that engraver! I did a test on a granite tile today ... it looked sooo awesome!

Thank you to everyone who has offered me help and suggestions. I know I'll be needing more until I'm fully comfortable with this awesome machine!


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