I searched around on this topic, seems like it’s brought up every so often but didn’t see any clear cut answers. Has anyone done a build using 2020 extrusions instead of conduit? I’m good with my hands, not so much with the CAD…and it looks like I’d have to design the modified parts from scratch. May make the build more fun…who knows. I just happen to have a lot of 2020 extrusions lying around from other printer projects, so I’d like to utilize those if possible.
I think openbuilds.com could be a good place for such a project. The tubes are a crucial part of the v1 designs, modifying the design would be an enormous task, not sure if it’s worth it…
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One of the primary things that makes the MPCNC work is having cheap, steel skate bearings running along steel tubing. Steel on aluminum is not going to work very long, so in order to make your 2020 design work, you will need to rework (and source) your design to use something like Delrin wheels. That is a major redesign and probably an expensive one since there are 45 skate bearings on the Primo. If you really want to use 2020 extrusions, you may want to consider a two-rail design like I see on so many other CNC machines. This would drastically reduce the number of wheels needed, and I’m sure you can find some suitable designs at the link Tubinbjorn posted.
With that said, I did do some thinking about a MPCNC design that used some 2020 extrusions. I was exploring/musing about the idea of a portable MPCNC that fit into a large suitcase. In that design the base and the legs were 2020 extrusions. This was partly for weight and partly to have a rigid frame so that I didn’t have to worry about the flatness of various tables. In that design, the spoil board had an array of slots that aligned with the 2020 “joists” so that the hold downs could use the slots in the 2020 extrusions. I though the Burly where the steppers don’t hang over the rails might be a better MPCNC for that design.
I’m a firm believer in the idea of starting from the right place.
Not necessarily this one, but there are many projects that start with “I like this but want to change this one fundamental thing…”
Yes, it’s generally possible, with enough work. I could take a 1982 Chevette and turn it into a 9 second drag race car, too, but would it be worth it? (Yeah, I did it, and no. No it was not worth it.)
There are some gorgeous extrusion based CNC machine builds out there. I think that many of them would even end up cheaper than re-working an MPCNC to be extrusion based, and even end up as superior machines, being that they were designed that way in the first place.
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Fair enough. To be clear, I love the design, and the community behind the project. That’s why I wanted to build one. I’d just also like to make use of material I have on hand, even if that means more work for myself. Appreciate the discussion.
Have you priced the conduit? In the upper midwest US, a 10’ section of 3/4" conduit is $9.75. The rework that you’re considering would represent a significant overall cost increase.
Use the extrusion to build the table you put the MPCNC on. Use the engineer’s recommended material for the actual machine.
To be honest it wouldn’t worth it. Not only because you’d have to redesign everything (that part could actually be fun), but I’d say more importantly because it would be far less rigid. 20mm square extrusions is far weaker than 25 mm round stainless steel tubes, by orders of magnitudes.
But the extrusions can be useful, you could for instance use them to build an enclosure around your MPCNC.
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