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Author Topic: Laser Cutter Questions  (Read 2391 times)

Catastrophic

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Laser Cutter Questions
« on: June 01, 2012, 09:23:22 AM »
Hey all -


I have recently been dipping my toes in the refreshing sitz bath that is the 40W CO2 Hobby Laser.  To those with far more time logged on the laser than I, perhaps you could spare a few moments to educate me?


1)  After I thoroughly RTFM, and then re-RTFM, I feel fairly confident in my basic knowledge.  As I understand page 16 of the manual, the focal length of the laser is 2" and the distance between the work surface and the aluminum mounting bracket should be 2.77".  I cut a small piece of cardstock to 2.77 for ease of measuring since the original ruler that came with the laser is most likely long gone.  However, I always find the honeycomb MUCH closer than that when I get on the cutter so I'm wondering if I am misunderstanding the manual or perhaps looking at the wrong mounting bracket.  The info in the wiki states the distance from the diode to the work should be 54mm, which does jive with the 2.77 number to the bracket, but it still doesn't explain why the cutting table is consistently well within that distance...


2)  Can someone give me a few recommendations on cutting speed/power/pass ratios for certain materials?  I spent last night practicing on a 3/16 sheet of plexi and experimenting with different ratios, but I was never able to find one that produced the smooth clean cuts that I see laying all over the table there.  Same goes for wood - what ratio was used on the coopcake parts or the wooden familab keyring thingies?  The unknown variable in all this is that I don't know if my 2.77 is correct, so it may be that my surface is at the complete wrong distance from the diode.


If someone can clue me in to these answers, I would really appreciate it.  If I can master this particular tool over the next few days then I would be happy to teach others, I know there are several of us newer members that would benefit from it.

Chorca

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Re: Laser Cutter Questions
« Reply #1 on: June 01, 2012, 10:11:43 AM »
54mm is correct. The manual states 2.77 in, which WOULD be correct if we had gotten a normal, purchased, off the shelf machine from them. However, we got a discount on a demo model, that had a different focal length lens in it. The 54.4mm was a result of experimentation by myself and tetsu.

Catastrophic

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Re: Laser Cutter Questions
« Reply #2 on: June 01, 2012, 10:20:34 AM »
Well that explains alot.  Maybe we could determine what the correct distance to the bracket is and make a convenient measuring square instead of having to put calipers down there?

Chorca

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Re: Laser Cutter Questions
« Reply #3 on: June 01, 2012, 10:22:55 AM »
If you look around on the computer, there should be something called "ruler" that I made awhile ago. We use the calipers to measure. If you measure from the top of the bracket to the bottom of the work surface, set it to 54.4mm, then cut that out, you'll have a little ruler that you can use. If it's not on there, we may need to make it again.

Catastrophic

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Re: Laser Cutter Questions
« Reply #4 on: June 01, 2012, 10:43:34 AM »
Yeah, Tom showed that little tool to me when he gave the rundown,  but I wasn't able to find it when I started working which is what led me to Page 16 and the erroneous 2.77. Speaking of, the laser for newbies section of the wiki advising ppl to check that page should probably be amended so that other wayward students don't make the same mistake.

Waterbury

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Re: Laser Cutter Questions
« Reply #5 on: June 01, 2012, 01:37:14 PM »
omfg, we must have etched 50 of those L-Shaped Rulers in the last year. I know tools walk, but they are useless for anything but the laser. What, do people keep them as souvenirs?!
"The American, by nature, is optimistic. He is experimental, an inventor and a builder who builds best when called upon to build greatly." ~ John F. Kennedy

Chorca

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Re: Laser Cutter Questions
« Reply #6 on: June 01, 2012, 01:46:32 PM »
I think I'm going to invest in small chain or string to start tying things to each other so they can't walk.

ThantiK

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Re: Laser Cutter Questions
« Reply #7 on: June 01, 2012, 01:52:26 PM »
As far as cutting goes, I pretty universally use 20% speed, 100% power for cuts.  I know some people prefer doing multiple passes, but I haven't seen the need.


If you need to do thicker than that, go down to 10% speed - also double check nobody's been messing with the current regulator.  Some people have a tendency to mess with that, instead of just adjusting things in software.  When running a cut, adjust the current to a little under 10mW - don't go past that or it shortens the lifespan of the laser tube.

PockyBum522

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Re: Laser Cutter Questions
« Reply #8 on: June 07, 2012, 12:07:16 AM »
BTW There's about three of the L ruler thingies in the laser itself, if you open up the cover and look to the right of the bed.

AtomicProf

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Re: Laser Cutter Questions
« Reply #9 on: September 24, 2012, 05:06:14 PM »
Maybe -- etch into the side of the L Ruler... "Keep at Laser"
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Simply7

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Re: Laser Cutter Questions
« Reply #10 on: September 24, 2012, 05:35:05 PM »
Someone has already done that on a few

Waterbury

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Re: Laser Cutter Questions
« Reply #11 on: September 28, 2015, 11:42:45 AM »
Agreed
"The American, by nature, is optimistic. He is experimental, an inventor and a builder who builds best when called upon to build greatly." ~ John F. Kennedy