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Hi all,

I've been digging for some information on how to build a CNC milling head for an Ord Bot Hadron. Do you have any information?

I know the Ord Bot wasn't designd for this and the belts can't handle a lot of pressure, but I am fine with that and just want to play with some simple PCB milling.

Thanks

It's not the belts that are the problem -- the Shapeoko, a CNC milling machine based on MakerSlide, uses MXL or GT2 belts too, and they're not the limiting factor. The most trouble I expect you'll have with the bed being able to twist slightly around the Y axis. In other words, if you press down on the left or right side of the bed, it'll give a little. It is much more rigid around the X axis. That said, if you tighten the V-wheels a little more than you would for 3D printing, I don't see why you would not be able to mill PCBs or really soft materials (foam, machinable wax). The easiest way, IMO, would be to buy a Chinese 300 W DC spindle and attach it to the X carriage instead of the extruder. You can even buy one with a power supply and a holder, but since you already have a 3D printer, you could print the holder instead.

Didn't I see Bart working on a small DC motor (RC car) powered spindle a while back? I'd figure something like that would be ideal for milling circuit board traces.

It would be, indeed. It may even be better than the Chinese spindles, whose main advantage is that they're available now.

The seller I bought my ord bot from, Tool3D, used a dremel on their platform and did some light duty milling with it. Here's a link to some of their videos: http://tool3d.net/index_files/Tool3DProjects.htm

I have a heavily beefed up Shapeoko2, and I'm building the Hadron. I have all of the parts milled from aluminum and G-10, partly assembled, and am waiting on the rest of the components.

I can say from the Shapeoko2 experience that you'll probably want to make a few changes to prevent twisting of your platform and gantry when plunging, or taking a deep or fast cut. As said above, the Y axis platform will deflect to the sides when your spindle plunges into the material. One easy solution might be to double up the Y makerslide, so there is one on each side, supporting the full width. You might also consider rotating the makerslides to a vertical orientation so that the direction of force is more ideal for the v-wheel.

Similarly, the X/Z assembly, and the distance to the spindle act as a lever that will pivot on the v-wheels when enough force is applied. You might try simply adding more v-wheels to the existing plates. On my Shapeoko2, adding additional wheels to the Z-axis plate made a noticeable improvement, and I'm considering doing the same for the X.

I'd start with a Dremel type tool to prove that it's going to work before moving to anything more expensive.