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CNC-2116 - Up and running, sort of (2015-03-21)
Yvan256:
Another small update. I had problems with the particle boards, so I've switched to MDF. I'm also unsure about the whole "make bigger panels with indexing pins", so I've changed the size of the machine back to one that would allow me to cut the panels for my MVS-99-6 desktop arcade machine.
Here's the progress on the Z axis. It's a variation on TinHead's design from his Valkyrie CNC, made to reduce the width of the whole carriage. By using a "T" configuration for the front plate/rails assembly, instead of putting the rails on the side of the front plate, I was able to keep the whole thing at only 3.5 inches wide.
It's missing four mounting holes on the front plate, a top plate with the motor and the threaded rod and nut, but this is more or less complete for the Z axis. It's also the X axis carriage. Some of the holes for the bolts+bearings assemblies are oblong, to allow for precise alignement with the rails.
Included is three photos, showing the two parts alone and assembled.
Bengaz:
You lot should work for NASA!!! :applaud:
menace:
You (and crashwg) have inspired me into my next project :angry: ;D. I like how your linear bearings look compared to the standard DIY variety. Did you regain much work space doing that versus the >< arrangement? I'm trying to make the machine size small but maximize the work space so anything that gives me more travel is desirable. I understand there is about a 4" loss in the x and y due to how the frame and router line up and my ultimate goal is to crank out some bartops. So a table of 24" x 48" works out to a working space of 20" x 40" that seem about right?
With regards to you stepper drivers--was this a circuit you just knew how to build or were you following instructions from someplace. It seems to me the electronics are the most expensive part of the build and I'm hoping to trim a few bucks from the budget.
Failing building my own, any thoughts on this combo: http://www.ebay.ca/itm/200806516142?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649
Keep up the good work!
Yvan256:
--- Quote from: menace on October 10, 2012, 08:24:27 pm ---You (and crashwg) have inspired me into my next project :angry: ;D.
--- End quote ---
First off, I'm glad to see yet another arcade builder embark on the CNC quest! If anything, we'll shortly be able to see more arcade-related CNC cutting videos on YouTube, I'm tired of watching 3D plates and router mounts videos. ;)
--- Quote from: menace on October 10, 2012, 08:24:27 pm ---I like how your linear bearings look compared to the standard DIY variety. Did you regain much work space doing that versus the >< arrangement?
--- End quote ---
The space gained is probably not that much, all things considered. Also, after playing with the Z-axis manually, I have to agree with tinhead about the aluminium angle being too soft for this configuration. His latest machine still uses a weird setup but it seems to be much better, at least according to him.
I still had to try using the edge of aluminium angle just to see how bad it was, because it makes the whole thing a lot easier to build. It might end up better with real v-groove bearings. However, with my fake v-groove bearings, this setup it didn't last very long because after moving it a few dozen times manually it already had a small play in the setup. I've also read that once the aluminium edges are compressed that it's fine after that, but you do need to "break in" the edges" with a program to run your machine on all three axis from zero to max, to wear/compress them evenly on the whole surface. For that reason, I went back (again) to the tried-and-tested setup used by people all around the world. I only have two six inches bearing assemblies made so far, but it runs a lot smoother than the edge rolling setup. And in that configuration, the wearing of the aluminium angle will be minimal since the bearing rolls parallel to the surface of the angle.
--- Quote from: menace on October 10, 2012, 08:24:27 pm ---I'm trying to make the machine size small but maximize the work space so anything that gives me more travel is desirable. I understand there is about a 4" loss in the x and y due to how the frame and router line up and my ultimate goal is to crank out some bartops. So a table of 24" x 48" works out to a working space of 20" x 40" that seem about right?
--- End quote ---
A 24x48" table with a working space of around 20x40" sounds about right to me if your Z axis assembly is around 4" wide and your X axis assembly is about 8" deep. However, those are rough estimates, I'd need to see your plans to make sure.
You will lose a lot in the Y axis because of the X axis assembly. But you can't make this assembly too narrow because you'll lose structural strength. As for losing working space in the X axis, you can work around that a bit by making your Y rail go "outside the box". See how the Y rail of the blackFoot is assembled (first photo)?
The best thing would be to make the plans in Sketchup or similar, down to the last detail. That way you can really squeeze out every last 1/16" possible and know in advance what's needed, the dimensions of each part, etc.
--- Quote from: menace on October 10, 2012, 08:24:27 pm ---With regards to you stepper drivers--was this a circuit you just knew how to build or were you following instructions from someplace. It seems to me the electronics are the most expensive part of the build and I'm hoping to trim a few bucks from the budget.
--- End quote ---
It's more or less an already known circuit to which I'm going to try and add an Atmel microcontroller to lower the cost instead of using a pre-built controller chip. The IRLZ14 transistors will do the heavy lifting and the microcontroller will do the logic between the commands of the computer and the transistors. However, it's going to be crude at best with no power control or microstepping, so it's more of a temporary solution. And there is now very cheap TB6560 controllers on eBay, so I'm probably not even going to bother making my own at all. Since surplus motors are 24v, I'll have to try and get three used 24v laptop power supplies from the local recycling center. I hope I'll be lucky enough to find three power supplies of the same model.
--- Quote from: menace on October 10, 2012, 08:24:27 pm ---Failing building my own, any thoughts on this combo: http://www.ebay.ca/itm/200806516142?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649
--- End quote ---
Actually, for all the included stuff, it's a pretty good price. Those motors will probably be more than enough, the controller is the one I have on my watch list and even the power supply and parallel cable are included. Frankly, if I had the money I'd be tempted to order one of those kits myself!
What do you plan to use for the milling tool? Dremel 4000? Bosch Colt? Dewalt 611? Hitachi M12VC? The weight and power of your tool will decide of a lot of factors for your machine, i.e. the structural strength needed, etc. I'm still new at this, but my one tip would be to never underestimate structural flex caused by weight.
Yvan256:
As you can read from my reply above, I've decided to switch back to the usual bearing assembly used by hundreds if not thousands of people worldwide. In building the Z-axis to test things out, I found out that the aluminium angle edges wear out too fast and too unevenly. Real v-groove bearings and breaking in the machine would probably work but I don't have nearly 150$CAD for bearings alone.
So, yesterday I built the first two bearing assemblies, six inches long each. I did have access to my father's drill press, so the holes for the bolts are at a perfect 90 degrees. The holes were tapped manually but with a cut bolt inside the drill press, so the threads are at a perfect 90 degrees too.
These assemblies roll extremely smoothly on the sides of the aluminium angle. I would also not be afraid to put the weight of the M12VC on these, as opposed to my previous setup.
Sorry about the uneven lighting in the animation, the DSi isn't exactly a high-end camera. :P
note: the aluminium angles do not touch, it's an optical illusion because of the angle of the camera. There's about 1/8" space between the "tops" of the angles.
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