CNC Build, Day 22 – parts is parts

The X-transmission nut has really been giving me a hard time. It hangs in there for about 15 minutes, then pops loose, and I end up spending 20 minutes fixing the silly thing. This part of the design really needs to be cut accurately, and my hand drilling isn’t cutting it.

I have been having problems with my CAM program; my free trial ran out, so I am on the hunt for another one. Most CAM programs take .DXF (AutoCAD) files as input, so I decided to try out a full 3-tier Cerberus approach to building myself a new X-transmission nut.

I downloaded SolidEdge 2D, which is a professional-grade CAD program, but completely free! They are trying to upsell to their 3D package, but I think I’ll be able to live for awhile with 2D (and converting to 2.5D in the CAM program).

After some fits and starts, I got SolidEdge kind of working, and was able to lay out the part with exact dimensions and placement. Nice. Saving as .DXF was easy.

I got it onto the PC and tried out LazyCAM, which is the free CAM that comes with Mach3. The folks at ArtSoft should stick to Control software (and they have, bless their hearts), because LazyCAM is… not feature-rich.

Rather than waste a bunch of time trying to learn a third CAM package, I decided to force CamBam to do the job. Turns out that the crippled version will only do one MOP per GCode file. So, I saved the MOPs off to separate files, and merged them together in WordPad. Not a problem.

An aside: next thing I have to do is raise the router mount, because there is *very* little clearance under the bit right now. Back to the show.

I tested out the cut, and started it up. Ran into the first “bug”; I was cutting out the edges of the piece first. That would have made the drilling part difficult. So I stopped the cut and edited the G-code to put the perimeter part last.

Start up again, drill #1, OK. Drill #2, OK. Drill #3 (actually a full-depth “pocket”), OK. Hey, we’re on a rol– oops. I forgot to add a “please raise the drill bit” after the pocket and before the perimeter cut, so now I have a full-depth diagonal gouge in the part. Oops. Edited the G-code again, put in the proper command, and re-set the machine to cut in a new area of the board.

This time, everything went perfectly. The piece looks great. I did cut it a little too close to the old part, so one edge is a little rough. Other than that, I didn’t even have to sand it. Nice.

Oh, I forgot and went way too deep, right down to 0.75″ So my table is starting to gain some interesting scars. shrug.

I spent some time putting away tools and moving the drill press. The garage looks pretty clean again, except for all the sawdust. It’s still on the list of TBD.

I used the drill press to do the edge-to-edge holes through the part, and installed it. It went in really nice. No photos; the part doesn’t look so impressive unless you know what I had to do to create it.

With the part in and tested, I spent some time scratching my head, thinking about how I am going to mod the router axis to make best use of the new router mount. I did all the measurements, and ended up deciding that I am going to move the router mount up by about 2.5″. That will allow the router to touch the table if need be, but also give plenty of clearance for thick workpieces. Since the router mount actually holds the collet about 3″ below the bottom of the mount, I will just drill new holes for the router and install it in situ, rather than cutting the Router Gantry sides. Nifty.

So I have a little bit of CAD experience now, and unfortunately, I am still working on CamBam, so it’s feeling like I may end up buying it. grr. There are 2 other possible CAM programs to try, though, so we’ll see. And hey, maybe LazyCAM is secretly awesome and I just need to figure it out more. Who knows?

On the TBD:
– get a CAM program.
– drill the new router mount holes.
– get some vacuum already.