Actors want to be singers and singers want to be actors. The hacker equivalent to this might be that 3D printers want to be laser cutters or CNC machines and laser cutters want to be 3D printers. When [Kurt] and [Lawrence] discovered their tech shop acquired a 120 Watt Epilog Fusion laser cutter, they started thinking if they could coax it into cutting out 3D shapes. That question led them to several experiments that were ultimately successful.
The idea was to cut away material, rotate the work piece, and cut some more in a similar way to how some laser cutters handle engraving cylindrical objects. Unlike 3D printing which is additive, this process is subtractive like a traditional machining process. The developers used wood as the base material. They wanted to use acrylic, but found that the cut away pieces tended to stick, so they continued using wood. However, the wood tends to char as it is cut.
In the end, they not only had to build special jigs and electronics, they also had to port some third party control software to solve some issues with the Epilog Fusion cutter’s built in software. The final refinement was to use the laser’s raster mode to draw surface detail on the part.
The results were better than you’d expect, and fairly distinctive looking. We’ve covered a similar process that made small chess pieces out of acrylic using two passes. This seems like a natural extension of the same idea. Of course, there are very complicated industrial machines that laser cut in three dimensions (see the video below), but they are not in the same category as the typical desktop cutter.
super cool!
funny – I was using that very laser cutter just a few days ago. seems to be the redwood city TS, yes? ;)
I was also discussing this very idea (rotating and raster removing material) with a few of the regulars there. good to see this idea works!
will the TS guys allow this to be used by other people? how did you work it out with them to allow you to experiment like that?
good job!
That TruLaser Cell 3000 is one of the machines I work on! I’m a Field Service Engineer for TRUMPF in North America. YAG disk laser power delivered by fiber to a 5-axis machine. Fast, accurate, durable, and yeah, really complicated.
I think I’m in lust.
How much do those go for?
Depends on how much power you want. 1000W to 8000W available. Think in the range of a quarter million or so, though I never see prices on anything so that’s anecdotal.
Thanks!
Yes we did it at the Redwood City TechShop. The nice thing about this system is it doesn’t have to wire into the machine at all. I build the rotary axis so I could mess around with it at home and not wire directly into anything owned by TechShop, but it would be easy to adapt the rig to work with an existing Epilog 3 Jaw rotary axis, and that would simply the build quite a bit. For someone with a laser cutter the hardest part of the build is probably the 3 Jaw Chuck arbor since you need a lathe to build that. The TechShop staff have been very supportive.
What about the focus? If you vary the height the beam intersects the target doesn’t the size of the beam change?
For simplicity we don’t add an axis for adjusting focus. However we do a trick where we put the focal plane 1/3 from the top of the cylinder so you can effectively get two focal lengths by rotating 180 deg and cutting in reverse.
Esprit (and quite a few others) do a cam toolchain for turn and burn (like this but on a edm but lacking the raster detail pass capability), though the toolchain is mega expensive, but it is very stable and developed. Workflow would be cad program of choice->esprit->gcode into whatever format you have a cam post processor file to suit.
https://www.youtube.com/watch?v=3xk5J48h2MQ
What they do bring to the table not discussed is the ability to use the machine as a ultra precise electro erosion (or in this case it would be laser) lathe with continuous rotation for spindles, crankshaft with co-ordianted axis moves while turn etc, and thats the point of toolpath coding when a mature cam toolchain proves its worth. Im currently fabricating mk2 of my edm worktank spindle for a edm from stainless based around the vdh castings but in a stainless pour.