I finally forced myself back out to the shop to work on the CNC machine again.
With graphics in-hand, I was able to put together toolpaths and get the parts cut out.
An aside; there is no direct “mirror” function in CamBam. You have to either resize to -100% or use the transformation matrix. I needed to flip the vacuum shoe, and I ended up having to build a bounding rectangle around it, then flipping the whole thing, then deleting the rectangle, because the “resize” command seemed to want full dimensional values. I did not think to try using percentages. hmm. Back to the show.
This was my first time using MDF (I decided to try out some 3/4″ MDF instead of Birch Ply, because my local HD does not have Birch Ply in 2×4 sheets, only sanded ply and MDF … grr). It definitely machines differently than plywood. It’s essentially sawdust all the way through, so the dust that comes off is like flour. And the unsanded edges are much nicer than plywood. I like the look of ply, and I don’t think I would build a whole CNC out of MDF, but for the 2 parts I made, it worked pretty well.
With the new parts (the gantry side and the “upside down” vacuum shoe), I was able to make big progress. In particular, all of the wood parts of the Y gantry are now in place! w00t! I had to do a bit of boring out the edge holes to make stuff fit, and there are some cross dowels that are not in quite right. But the whole thing looks and feels very sturdy (at least, sturdy enough to cut out another one… 🙂 ).
I also made a bunch of progress on the Sketchup model of the torsion box. I figured out that if you make a copy of the parts, any changes you make to the copy will be transferred to the originals, too. Very nice. Based on the sizes of leftover material, I figured out that I can make the table 4″ longer than I’d previously designed for. I don’t know that this necessarily helps me. But it’s there if I need it.
After confirming the lengths I will need for the rails, I ordered 2 more pieces of angle, to serve as the Z axis rails. I will use the previously purchased Y and Z rails as the Y rails, and the X rails are fine. I have a question whether the Y rails are going to fit properly; my rails will be 60″ long, and I measured out the top of the gantry at 59″. I hope there’s some slack, or I’m going to have to put in some pockets (I don’t feel like cutting off 1″ of angle). The rails should be here in a day or two.
With recuts done, my TODO list got a lot shorter.
I need to complete the Z axis, attaching the other side’s “front” (the “back” holes are where the rail mounts), and then attaching the top and bottom assemblies.
Once that’s done, I need to drill holes in the rails. Then I can install the rails, which will get me ready to install the bearings, which will then leave just the motors and chains to install.
There’s another day or two of work on the gantry, and I’ll be waiting on the table.
I need to figure out lumber for the feed tables for the table saw, so that I can start getting the table cut out. I have a feeling that I’m going to be buying the lumber. I’d like to use the stuff I have on hand, but it’s in kind of sketchy shape. I don’t know. I’m still thinking about it. 2x4x8 are about $3 each at HD. I need 8 of them. So I’m stressing out over $25 in lumber. I’ll need a bunch of lumber to make the legs for the CNC table, too, and that stuff needs to be larger. The feed tables should be “knock down”, so that I can store them when I’m not using them. The CNC table needs to be burly, because it’s never, never moving. All the “used” lumber I have is of the 2×4 or 2×6 (or 4×4 or larger) variety. So it makes more sense to use it for the CNC table (as long as it’s dry enough). The feed tables need to be as light as possible, so I am thinking that I’m going to build them out of 1×4 or 2×2, to keep them svelte.
There are a lot of projects involved in this CNC project. It’s not a “weekend” adventure. We’re entering week #4 on it. Wow.