New user, need build help

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New user, need build help

Postby Gravatel » Sun Feb 23, 2014 2:46 pm

Hello all,

I would like to build a laser cutter and from what I have read it would be a 2 axis router, I would be using it to cut packaging foam (the soft grey type for camera cases 110mm max), thin plastic and very thin wood. The router would be 30inces x 20 inches.

I am in the UK in Buckinghamshire so I don't mind travelling if someone can help me build the machine.

Something like this really http://www.youtube.com/watch?v=k73eT3ehYB8

Thanks!
Gravatel
 
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Re: New user, need build help

Postby mattrsch » Sun Feb 23, 2014 6:51 pm

110mm thick is too thick for most lasers, you should be able to do the thin wood though. For cutting thick foam I would recommend a hot wire foam cutter:
http://youtu.be/hV79pjFDdRY?t=3m48s
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Re: New user, need build help

Postby Gravatel » Mon Feb 24, 2014 12:00 pm

For the cut outs I want to do would be impossible with a wire cutter.

What mm thickness could be done with a laser?

Thanks
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Re: New user, need build help

Postby canadianavenger » Mon Feb 24, 2014 2:22 pm

I'm guessing you are thinking that the laser beam is columnar in nature making a straight vertical cut for virtually any thickness. This is not true, the beam is actually conical in nature. The beam is focused to a fine point at the cutting/engraving distance. The beam is concentrated enough to cut at some distance +/- from the focal point [actual distance will depend on the material, and laser power], beyond that it'll just heat the material [to the point of melting or charring in some cases]. The edges will be trapezoidal and not perpendicular.
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Re: New user, need build help

Postby Gravatel » Mon Feb 24, 2014 4:09 pm

I have a basic understanding how the laser disperses and the foam tapers depending on the length. However I thought a stronger psu and lens would augment the laser to prevent this?

As for the build can anyone recommend me on the parts I would need from my OP?

Thanks
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Re: New user, need build help

Postby TLHarrell » Mon Feb 24, 2014 6:37 pm

I have cut 1" (25mm) foam in my laser with a 1.5" focal length lens with no visible issues. Using a 5" lens it should be possible, but there will still be some angle to the cut. If you focus the beam point at the center of the material, the sides of the cut will be somewhat hourglass shaped, being slightly wider in the center. It should be capable of cutting up to 110mm foam. Since this is for camera cases, the slight beveled cut should not be an issue at all. You do realize though that you cannot control cut depth, so if you want foam left on the bottom, you'll have to stick another piece in there.

Also, foam engraves very nicely. Text and logos can be engraved into it and they show up very nicely.
40w Full Spectrum Engineering 5th Gen Hobby 20"x12" w/ Rotary Engraver
South San Francisco Bay Area - Sales and Support Representative for Full Spectrum Engineering
408-47-LASER - Skype: whitelightlaser-thomas - Facebook: White Light Laser
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Re: New user, need build help

Postby Gravatel » Mon Feb 24, 2014 8:48 pm

Hmm I feared this could be the problem. I would be cutting between 5mm to 110mm, but if I can get the laser to cut up to 55mm with no dispersion I would be more than happy, and then get the thicker foam press cut.

I have seen this video (http://www.youtube.com/watch?v=gHb51CfnubA) where they use a laser to cut 30mm thick foam. Would this laser setup be very expensive?

Cheers!
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Re: New user, need build help

Postby TLHarrell » Wed Feb 26, 2014 1:07 am

You would need a machine with enough depth to load the foam, and use a 5" focal length lens. There is a little "burn back" on the foam anyway, so the cuts are not accurate to the thousandths, but well beyond anything you could cut by hand. Only concern I'd have with such thick material is clearing the smoke out of the cut. The farther into a kerf you are cutting with a laser, the less likely it'll make it through. I would definitely see if you could find somebody with a 5" lens to test cut some for you.

Found my pic finally:
Image
40w Full Spectrum Engineering 5th Gen Hobby 20"x12" w/ Rotary Engraver
South San Francisco Bay Area - Sales and Support Representative for Full Spectrum Engineering
408-47-LASER - Skype: whitelightlaser-thomas - Facebook: White Light Laser
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Re: New user, need build help

Postby Gravatel » Wed Feb 26, 2014 9:33 am

Would 75mm cuts be doable? Can anyone recommend what I need for that laser?

Also your picture isn't showing TLHarrell :/

Thanks
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Re: New user, need build help

Postby TLHarrell » Wed Feb 26, 2014 5:42 pm

Strange. Should be set to public by default.
40w Full Spectrum Engineering 5th Gen Hobby 20"x12" w/ Rotary Engraver
South San Francisco Bay Area - Sales and Support Representative for Full Spectrum Engineering
408-47-LASER - Skype: whitelightlaser-thomas - Facebook: White Light Laser
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