Updated suggestion attached. Increased envelope to 300x190x150. If you intend to use long bits you may want to reverse the Z-axis. Sketchup file and parts list attached. Parts list does not include the hand cut plates.
That's a nice build that one Rick, I had already saved some images of that format but I hadn't found the SketchUp files ............. so, many thanks for that mate From rotating that around I can see that it's infinitely adjustable, I like that. More height can be had just by installing the support pillars from the Z axis higher up on the main column. In the image that pillar seems to be at least 3" further down than where I would need it. The idea of the 'Out-Riggers' is also on one of my drawings, as I can see how that would stabilise it, and to further stabilise it you can obviously bolt the entire thing down onto a workbench ....... as I'm going to do. I got an email from Ryan Lock this evening, the good news is, they do supply the 'MiniMill', it's just not on their website yet, so that idea isn't dead in the water just yet ! Yes, those custom made support plates are going to be an issue, but I guess I can make some of my own once I get my standard 'MiniMill' ! Or could somebody on here make some for me ? There's one more thing I need to look into, both tracks X and Y are facing up ( as are most CNC builds I've seen ), I need those underneath as those will just fill up with bits of plastic in no time ! It must be possible to hide the lead screws underneath the assembly somehow ........ or is there a particular reason why they're always on top ? TURK
There's really nothing special about those custom side plates. Get some flat bar stock of the proper width, cut to length with a power saw or even a hacksaw and then drill a whole lot of holes on a 20mm grid. I assume your Proxxon will accept a 5mm bit. It would be a whole lot quicker than assembling a mini-mill just to fabricate them. Note: the drawings are based on using 3/16" (4.76mm) thick plates which requires 10mm screws. If you drop the plate thickness to 4mm or less you'll need to drop the screw length to 8mm. As far as inverting the C-Beams to avoid debris, it's really not that simple on this style of mill. Some have considered using paper or fabric bellows to cover them but I haven't noted any successful designs being posted. I'm planning on building a similar design in the next couple months (which is why I had the design files so readily available) and I was just planning on mounting some flexible plastic shields to trap or divert debris and vacuuming a lot as I go. Please keep us updated on progress. Rick.
Hi Rick You guys must be thinking that I'm quite a pain in the neck with my constant questions ................... and indeed I can be But I really like to do my homework before hand, by nature I have a very inquisitive mind, so I like know what to expect. I don't like surprises ......... specially if the error could lead to you being out of pocket by a few hundred quid ! ( or bucks ! ) I've seen many off the shelf kits and member builds, and for me to find the ideal solution that will fill my needs is to find the flaws in the builds I've already seen. The biggest flaw ( or setback ) that I've seen so far is, the visible lead screw ! I know you'll say that most machines have spoil boards on the drive mechanism to hide the screws, but some don't. That would be a disaster for me,as I'm working with plastics and shaping PU foam, both those materials produce static electricity which will cling to metal surfaces, and for bits of plastic to stick to the drive screw, I don't think that's such a good idea. I've seen the paper bellows thing you mention on some industrial machines, so that would work, but there may be a simpler solution. I'm currently looking at two different machines, both very different in styles. At this point could I just mention something that had me questioning the dual linear actuators for the Y axis. As I don't know a great deal about CNC machines ( all too obvious from my ramblings I know ), I thought that if you had two separate stepper motors one for the left runner and one for the right runner, that there maybe the potential of one of the stepper motors running out of sync !!! So my reasoning was to stay away from a potential hazard. I've since then watched Scotty's video that he mentioned earlier in this thread, and in there he mentioned he had ordered an 'Abus' ( I think it was Abus ) controller board. He also mentioned that on that particular controller board that two of the stepper motor inputs were 'twinned', are all controller boards like that ? Apologies for all the dumb questions guys, but wait til we get round to the software stuff ! Forget to mention .............. I most certainly will mate TURK
What you want is a bellows made from plastic or some other durable material. They protect lead screws and the ways of a CNC machine by folding/unfolding as the linear axes move. I've been working on a set for my own use, but keep getting distracted by other projects. But at a basic level, you might take a look at something like this: Bellows I'm working on a set using neoprene cloth laminated to an ABS 'skeleton' myself. But there are clearly a number of ways to go here. -D
Attached is a Sketchup file showing a protected screw approach. The whole X-beam moves rather than just the gantry plate and the Y-beam has to be raised above the table to allow for the extra drive plate. Whether it's worth the extra effort is up to you. You still need to find a means of dust control though. Debris will affect wheels even more than it affects screws.
I use a dust shoe with vacuum attachment which keeps things pretty clean. A shoe might be difficult with your application, but a well-placed vacuum nozzle would help. You might also take a look at Sonny Lowe's "Sponge Leadscrew Sweep" for keeping the screws clean: The MakerSL Customized OB Minimill
I just go for 2 small plastic roller blinds, attached front and rear of the base board, each of which just expand and contract as needed.
