Cheap, 3D printed CNC

[Trakyan]

Not necessarily a 3D printer (you could strap a hotend on there!), but it is 3D printed. Thought people here might be interested, but if it's against the rules please feel free to remove it mods.

I've just finished the design of a CNC that's built from some 3D printed parts and stuff from the hardware store as part of one of my university courses. The GitHub and HaD links to the project/source files are
https://hackaday.io/project/103498-b...e-small-budget
https://github.com/Trakyan/BevelCNC/tree/master
for anyone interested.

Disclaimer in advance: I'm not trying to sell anything to anyone, at all.
As part of this project (it's a business/entrepreneurial course) my lecturer wants me to do some research on this as a product, so I've put together a short survey I'm hoping people won't mind filling out.
https://docs.google.com/forms/d/e/1F...9-8Lg/viewform

Thanks in advance for anyone who filled out the survey!

[curious aardvark]

so are there any actual pictures of the machine ?
Or in fact of anything :-)

And while you're here, presumably you've done a bit of research into arduino type boards to run these things.

I've got a 2.5watt laser, with a little daughter board.
Apparently I need to plug two 2 pin plugs into the two sockets on the board to run the laser. The board on my current laser engraver won't do it - no way no how - also doesn't have the power to run it directly (tried).
Looking around I can't find anything else that will take 2 2pin plugs (2 3 pin plugs, not a problem). To be fair I don't really knoiw what I'm looking for or whether I can use three pin plugs with just 2 wires.

Just want a laser engraver board that will run grbl and has 2 2pin sockets for a 12v laser.
my laser: https://www.ebay.co.uk/itm/Focusable...8AAOSwwz5aqkmF

It's a bit annoying.

Filled in the survey :-)

One criteria for a desktop cnc machine would be that it fit on a smallish desktop. I have no permament space for one. One reason I put an aluminium base on my laser engraver - it can now sit on top of things. 'course it can't engrave anything at the moment as I am laser-less. Got a cheap 1 watt 5 volt one hopefully arrving next week, but would really love to use my 2.5watt job. There are a lot of them being sold - so someone somewhere must make a board that works with them. I just don't really know what I'm looking for.

[Trakyan]

Thanks for filling out the survey!
The answer is no, I don't have any pictures of the machine yet. There is a "total_assembly" module in the .scad file which renders an assembly of the machine if you want to see what it should look like. I just finished the files and thought I'd release them for anyone interested. I'm working on getting the parts printed at my university since printing them myself has proved troublesome. I have an old printer, with old abs (at times the extrusion line completely bubbles up like a foam from all the evaporating moisture) and a cold house so predictably I've only had failures. I'll be doing a build log and demo videos once I get the printed parts in hand. I guess I was a bit over eager to get the files out and felt like I should back up my promises of an open source machine if I'm asking people to take time out of their day to help me out with a survey.

I'm somewhat confused as to why it's warping since it's printer that's enclosed from all sides (bar the top, which is covered by a plastic bag to enclose it but still give the reverse bowden tube room to move) and it actually gets fairly warm inside the enclosure. I've changed a couple of things since I last printed, namely the 0.4->1.2 mm nozzle, and larger layer heights to go with it, plus the plastic has moisture problems it didn't have before. I guess I'm also printing relatively large, flat surfaces too.

As for the plug/pin issue, you can always use a 3 pin connector with only two wires connected, right?

As for the size, yeah that's a bit of an issue for some people. For me, not so much, I currently live at a place where I've got room to spare, mostly because I don't have much furniture. My design is similar to the MPCNC in that it uses steel tubing as the rails/frame so the size of the machine is really up to the builder. I plan to prop mine up against a wall when not in use since I'll be making a fairly big machine (1m tubing for the XY axis, it was gonna be 1.5m but cost/practicality).

[curious aardvark]

lose the abs.

An enclosed printer is NOT a temperature controlled heated printer.
So abs will always be an issue. Plus pla is better anyway :-) (as you state on one of those links).

I'll have a look at the scad file.



So what's the bit in the middle ?

[Trakyan]

I'm only using ABS because it came free with the printer and I only have a partially full spool of PLA .
I just figured a small, enclosed printer with a z axis bed and a hotbed capable of reaching 110+ degrees would work considering some people print ABS on open frame i3s. I guess I was wrong.

As for what the center piece is, there are 6 components in the center assembly so I'll try and explain them all without a massive text wall. The two identical big grey parts are the sliders/bearings for the XY junction, the two red plates mounted to them (bottom and middle) are what clamps onto and holds the Z axis tubes. The top red plate is a mount for the Z axis motor (motor shaft points down and couples to a leadscrew that runs through the two other red plates). The grey block in between the two z rails and red plates is the Z carriage which slides along the two z rails, it's driven by a leadscrew which runs through it via two captive nuts, it has four mounting holes for interchangeable toolheads.

If you can tell me the part name (the module it's made from, they're listed at the bottom of the .scad file above the echos for the BOM) I can explain a bit more about the specific part you're interested in.

[Trakyan]

I've done a few tweaks (and working on a few more) to lower the amount of material needed. The top red plate will be removed, the corners have been trimmed down a bit and will be trimmed further.

[Trakyan]

Finally fixed the warping issue, a bit of abs juice and the parts stick with no noticeable warping. Gonna start printing all the parts once I tune in the tolerances I need.

Anyone got any thoughts on if I should go for 31.8mm or 25.4 mm tubing?