Good fit for carbide?

Hi Everyone,

I’m looking at the bench-top CNC for milling my own paintball gun, and wanted to get your thoughts if the machine was rigid/capable enough to do 3D milling of 6061. I haven’t seen a lot of examples of that on the website or in the forum.

Here’s an example of one part. It’s been designed for 3D printing at the moment, but would require multiple flips.

I’d think at the very least, it would need air on the tool for heat and chip evacuation.

I think yes, it’s quite capable of this, as long as you’re taking shallow cuts. I would recommend that you drill the barrel hole, not attempt to use the mill though. Would be fine to create a pilot for a drill press, but that’s awfully deep and hard to clear the chips out of. You’ll want to keep the end mill as short as possible with aluminum - stay at .75" or less if you can. This will certainly require a little creative jigging. Take it slow, clamp it WELL and it’ll be fine.

All that said, a shapeways metal print with a little cleanup might be a faster path (but not as fun).

Thanks for the feedback!

I have a HAAS and bridgeport at my work but I don’t have time to learn the CAM software and the machine. Plus, it would be nice not to spend my weekends there too.

I looked at DMLS and it’s too expensive overall. There’s another component that goes along with this part and Shapeways wanted $256… which compared to other B2B 3D printing houses is a pretty good price. I’ll probably end up doing 3-5 of these paintball markers in the end.

Alas, there’s also no discount for quantity and then there’s a good chance my tolerances would be off for the process. Even going from SLA to FDM I ran into fit issues, this me forgetting to add clearance tolerance.

What would you recommend for end mills? Uncoated HSS?

COATED, no “Al” coatings. You’ll pretty much only find carbide in 1/8", which the Nomad works with pretty well. Also, single flute. I didn’t know these even existed until I tried to aluminum. Onsrud makes a nice version of this, but they’re not super cheap. Work a lot better than the $2 version though. Get some cheap ones, get things worked out then use the nice ones for the final parts.

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2 flute ZrN coated carbide endmills work well with Aluminum and they aren’t much more expensive compared to uncoated ones. For endmills smaller than 1/8’’, uncoated carbide should work fine as I don’t see coated options often.

That part is not machinable as is. You will need to redesign it with filets to machine it. You could 3D print it in ABS then ream the hole to size, if plastic will work. That would be a LOT faster, cheaper and easier than milling it out of aluminum.

What features need to be held at what tolerances?