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How To Build With Delrin and a Laser Cutter

Posted by Soulskill on from the now-you're-thinking-with-lasers dept.

szczys writes: Laser cutters are awesome, but you have to bring your mechanical engineering A-game if you want to build resilient stuff using laser-cut parts. Joshua Vasquez has been building up his bag of tricks using Delrin and a laser cutter to build with techniques like press-fitting, threading, snap-fits, etc. that aren't possible or are non-ideal with the laser-cutting steadfasts of plywood and acrylic. Delrin (PDF) won't shatter like acrylic, and it has more give to it, so even the less precise entry-level lasers can cut joints that will have a snug fit.

4 of 28 comments (clear)

  1. And your favorite, hobby laser cutter is... by Overzeetop · · Score: 3, Insightful

    Is this a topic for those with access to the university's shop with the $100,000 laser all the students get to use for free, or is there an actual CO2 laser that can cut 1/4 or 3/8" delrin and plywood that's affordable for occasional home use?

    --
    Is it just my observation, or are there way too many stupid people in the world?
    1. Re:And your favorite, hobby laser cutter is... by mpoulton · · Score: 4, Informative

      Yeah I wish he went more into details on this.. he mentions a 60w laser at one point. Watts, wavelength, thickness, inches per second would have been nice.

      All commercial CO2 lasers for cutting use are the same wavelength, 10,600nm. Conveniently, that wavelength is completely blocked by almost everything except air - including glass, plastics, and water. This makes it comparatively safe to work with, as high power invisible lasers go. Standard shop safety goggles provide complete eye protection, and a direct beam to the eye is necessary to cause injury since the light cannot penetrate the cornea to focus on the retina like most laser beams. But I digress... The power needed to cut a material depends on the thickness, edge quality required, and speed required. Like welding, there are no clear rules, only general guidelines based on experience. 60W is not much power for laser cutting, and would be unlikely to make a clean edge on 1/4" plastic at any reasonable speed, or to give an acceptable cut on 3/8" material at all unless assisted by a compressed gas jet, which cheap and low-powered laser cutters do not use.

      --
      I am a geek attorney, but not your geek attorney unless you've already retained me. This is not legal advice.
  2. Re:Whoah, Delrin? by Anonymous Coward · · Score: 4, Informative

    Use Loctite 770 to prep the surface, then use regular super glue (cyanoacrylate). They also sell it at hardware stores as "glue for hard to bond plastics" as a 2 part system (the 770 and superglue). I've found the bond to be very strong this way (getting up to the point where Delrin will fail before the bond).

  3. Re:Whoah, Delrin? by Slugster · · Score: 3, Interesting

    Delrin is a thermoplastic; my first thought would not be to glue it with some other substance.

    (assuming you are in the USA, which you may not be)
    Harbor Freight makes a plastic welder for $65. There's better name-brand ones around for $300-$700.

    Two other possibilities for cheaply welding plastic: cheap soldering irons (~15W - 30W heat, $20) and mini heat guns ($10 - $30).

    If it is not a cosmetic issue, I have also seen thermoplastic parts repaired the following way... You get a small piece of aluminum screen, place it over the break and rub it in with a hot soldering iron.