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What wattage of laser is needed — Parallax Forums

What wattage of laser is needed

NWCCTVNWCCTV Posts: 3,629
edited 2014-12-04 23:52 in General Discussion
I have been thinking of making my own CNC Laser table. What wattage of laser would be required to cut through up to 1/3 inch sheet plastic and are there special licenses required for this?

Comments

  • Beau SchwabeBeau Schwabe Posts: 6,566
    edited 2014-12-02 21:39
    For reference, I have a 50 Watt water cooled CO2 laser CNC that will cut through 9mm plastic all day long.

    The only licensing might be how you deal with any out gassing from the laser process.
  • WBA ConsultingWBA Consulting Posts: 2,934
    edited 2014-12-03 00:30
    My 75 watt Epilog Legend 36EXT can cut 1/3" / 9mm plastic with ease using 12% speed and 100% power for the settings. I would not go lower than 50 watt for 9mm thick plastics if you plan to do a lot of it. You can do 9mm with a 30 watt laser if you make multiple passes, but then you need to ensure that your laser's gantry repeatability is accurate. Using multiple passes is helpful with a variety of materials even with a 75 watt laser (even though I can cut 1/4" Delrin with one pass pretty decent, I use 2 passes for a super clean edge and no "melted" artifacts)

    For more details/info, go to this link for the Epilog Manuals:
    https://www.epiloglaser.com/tech-support/laser-manuals.htm

    Open the 4th link for the Legend EXT Manual and read section 13. It has very good tips on power and speed settings as well as several pages of recommended settings for various materials on their lasers ranging from 30 watts up to 75 watts.
  • GordonMcCombGordonMcComb Posts: 3,366
    edited 2014-12-03 13:16
    Sheesh! Am I the only one without a laser cutter?

    Anyway, what type of plastic are you wanting to cut, Andy? You know that some, like PVC, emit noxious and corrosive fumes when burned. Make a habit of cutting this stuff and your laser will be gone within the week.

    I'm guessing the "license" you're talking about is FDA laser labeling and laws? You can read about that here:

    http://www.fda.gov/Radiation-EmittingProducts/RadiationEmittingProductsandProcedures/HomeBusinessandEntertainment/LaserProductsandInstruments/default.htm

    In addition, most states have their own safety requirements, though usually related to the practice of lasers on humans -- eye surgery, tattoo removal, physical therapy, and so on.
  • W9GFOW9GFO Posts: 4,010
    edited 2014-12-03 14:00
    For that thickness I would go at least 80W. Any less will be painfully slow. I cut quarter inch acrylic at 8 to 10mm/sec on 80 watts using a 65mm lens. 15mm/sec at 130W. It's quite frustrating that the mainstream laser companies use a percentage to set speed, it obfuscates their actual performance. Cutting speed will also depend upon accuracy of mirror alignment and focal length of lens used.

    No licenses required - at least if there are any, then I have been in violation for quite some time.

    If you are serious about building one I have an unused 80W Reci tube, power supply, main board and LCD control panel...
  • NWCCTVNWCCTV Posts: 3,629
    edited 2014-12-03 17:26
    W9GFO wrote: »
    If you are serious about building one I have an unused 80W Reci tube, power supply, main board and LCD control panel...
    What are you asking for everything?

    @Gordon, I was not planning on cutting PVC or anything else that could be hazardous. I will be implementing an air and filter system before even firing it up. Possibly a water type filter system such as those used in some paint booths.
  • WBA ConsultingWBA Consulting Posts: 2,934
    edited 2014-12-03 17:32
    GordonMcComb wrote: »
    Anyway, what type of plastic are you wanting to cut, Andy? You know that some, like PVC, emit noxious and corrosive fumes when burned. Make a habit of cutting this stuff and your laser will be gone within the week.

    I know you mean the other Andy, but in regards to plastics that I cut: Delrin and other acetals, ABS, thin lexan or polyethylene, Acrylic, and Styrene, but never PVC.

    No licensing required.
  • W9GFOW9GFO Posts: 4,010
    edited 2014-12-03 17:33
    NWCCTV wrote: »
    What are you asking for everything?

    Well, I don't know... I could use some security camera related stuff so maybe we could work out a trade of some sort.
  • NWCCTVNWCCTV Posts: 3,629
    edited 2014-12-04 19:32
    Rich, PM me. Let me know what you are looking for. I have some new and used items that I could part with.
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2014-12-04 22:13
    Andy,

    Safety first here! Commercial laser cutters diverge and parallelize the laser beam for steering, then converge it to a point at the last instant with a convex lens. This is important, because an undiverged beam, reflected off of a metallic surface, can cause extensive biological damage. A converged beam, OTOH, will rediverge beyond the focal point to a less damaging intensity. You should also install an IR-blocking lid with safety interlocks to turn off the laser beam when the lid is open.

    -Phil
  • NWCCTVNWCCTV Posts: 3,629
    edited 2014-12-04 23:52
    Phil, I have taken all safety concerns into consideration and will be following guidelines of commercial setups with safety/health being first priority.
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