Messing around with copper

(Nick) #1

I am super new to cnc machining and I have no one to teach me/to let me know when I’m doing something totally wrong.

Ok, so far I’ve machines cheap plywood and g10, and recently I’ve been trying to work on copper and aluminum, though I have yet to actually try aluminum.

I don’t have proper work holding or any cooling system set up, I’m just working with what I have at the moment. I started out using 1/16 flat end mill from carbide 3d, had my feeds and speeds fairly slow, and sat next to my machine through out the run spraying it with a jet of water from a bottle every 10 seconds or so. This actually worked for a bid, but it chewed up the copper in a funny way and after a while it just didn’t even work anymore. I lowered the speed, tightened all parts of my machine, but I still had issues.

The past two days I’ve been using a 1/8 inch ball nose endmill (from carbide 3d) and using super slow speeds, this morning I had it working, I was still sitting there with water the whole time, but it worked, though it still ocassionally shuttered. I changed the feeds and speeds/etc to be even slower and at this moment, I have it running without me squirting it, and without the shuttering.

I think the water actually caused the tiny flakes to stick around and clump up, and I think going slow enough with this non ferrous metal its stays cool enough and heat is not a problem. (especially because copper conducts so well, I imagine a lot of the heat disperses quickly.)

Feedrate: 2 in/minute
Plungerate: 0.5 in/minute
Depth Per Pass: 0.008 in

Also, I’ve found that setting the retract height to 4mm saves a lot of time, and with my setup/design that’s plenty of room.

pictures to show the funky copper work I’m doing, and the horrible method of work holding I use.
I’ll be messing around with different methods of workholding soon.

(Nick) #2

update: burned through the carbide 3d bits super fast, makes sense, they aren’t supposed to do metal like this haha.
I’ve ordered some that are made to work metal, I’ll update on how those work when they get here. (should be here tomorrow)

(F B) #3

The carbide3d bits are solid carbide, and are made to cut steel all day long. Copper should be no challenge for them. I don’t know which ones he uses offhand, but I know @RichCournoyer has been using the same end mills on steel forever.

(mikep) #4

Your speeds and feeds are wrong if you’re burning them up that quick.