Updated great rhombihexacrons

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Updated great rhombihexacrons
Updated great rhombihexacrons
Great rhombihexacron net
Net cut out on laser cutter

After a lot of adjustments, the laser cutter seems to be working okay, and producing fantanstic nets for making polyhedra.

Safety recommendations:

  • Wear protective laser goggles whenever the laser cutter has 12V power, even when you don’t expect the laser to turn on. The laser can turn on unexpectedly.
  • Never leave the laser cutter alone when it has 12V power.
  • Try not to look at the beam, even with goggles, when it is on more than about 25% power.
  • Cut in a well ventilated room, don’t cut materials that generate dangerous fumes.

General recommendations:

  • Red paper/card works the best, darker colour papers work better than light coloured papers, with white paper working really poorly.
  • Light coloured papers seem to cut unevenly – this seems to be because they initially reflect most of the laser power, but as they char they become more absorpative, eventually cutting very quickly when they char black. This makes it hard to score paper accurately, it is either almost unmarked, or is cut through. Darker papers cut more linearly with energy/time – so it is much easier to achieve consistent results. This is especially true when the laser might be accellerating, or a single location is covered multiple times.
  • A laser less than about 5W will cut dark coloured card, but no more. In my experience, these machines are not accurate enough for multiple pass cuts to produce a good result.
  • The soot generated by the laser cut quickly stains the paper, keep your hands and workplace very clean to avoid spoiling the final models
  • T2Laser was a great investment over the free programs for controlling the laser (‘Benbox’ is hopeless), I would recommend buying it. Zax (who built the programme) is extremely quick to respond and very helpful.
  • Following some of the tips contained in MarcoReps Important upgrades for the Eleksmaker PCB laser CNC machine video was very helpful. I will try to reintroduce the SilentStepSticks to the new board.
  • Buying a cheaper laser cutter from BangGood rather than getting the full Eleksmaker model was a really poor choice. I was plagued by poor reliability that seems to have been caused by the board on the cheaper model, as well as issues with the laser starting up caused by the way it operated the laser, I go into more detail in another post. Attempting to fix these issues took tens of hours to time over several months before I bought a proper Eleksmaker board which seems to have fixed the issues.
  • Preparing carefully for each print is well worth it – I run a ‘test rectangles’ print before trying each type or colour of paper (seen in the bottom right of the last photo), this helps my double check that the laser power and feed speed for both cutting and scoring are appropriate. I run ‘engrave frame’ before each run to check the paper is in the right place and the print doesn’t run off the side or hit the ends of the cutting frame.
  • Some simple changes can yield big improvements – I switched to keeping the whole cutter on a thin aluminium sheet, this keeps the paper a consistent distance from the laser, the mitigates issues with the laser pulling in and out of focus (which means it can cut quite inconsistently). Taping the paper and the frame to the aluminium sheet stops them moving relative to one another during the print.
  • Change your computer sleep settings and make sure T2Laser/Benbox is a top priority programme.
  • I found changing the belt tensioning devices to those recommended in Marco Rep’s video made a big difference to the overall quality and consistency of my prints (and I was able to 3D print them!), and other small 3D printed components made a big difference to cable management.
  • Thin double sided tape has been the best tab attachment I have found. Glue (which needs some compression when drying/setting) is too fiddley and needs more access inside the models than is really achievable. Tape on the exterior can actually look okay for a first attempt of a construction, but needs to be designed out eventually.
  • Note that Rhino 6 exports .dxf layer colours in a way that T2Laser does not understand. You have to set the colour of each object in the ‘display colour’ setting, rather than having the display colour setting ‘By Layer’. This can be confusing, with online .dxf viewers picking up the ‘by layer’ logic as well as Rhino.

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