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Discussion in 'CNC Mills/Routers' started by Dean Suominen, Jul 3, 2017.
Wanted an "all in one" box for the computer and the drivers/controller so I dug out an abandoned water cooled computer case and started hacking away at it. I put the controller in an old CD rom drive with the resistor board to keep it neat and clean. Plugs harnesses plugs harnesses... more plugs...more harnesses. For the motor drivers, I mounted them vertically as there are going to be 3 fans on the top of the case pulling air up. The power supplies for the controller and spindle are mounted on the bottom and the motherboard backing. The air will be brought in through the PCI slots in the back of the case, upwards and should keep everything cool using 5 120mm fans. Half of the build is made up of stuff laying around in storage. I have a 4x8 sheet of polycarbonate at 1/4" and another 4x8 at 3/8". I also have a 2'x3'x1/4" sheet of T6 aluminum to build the plates out of to replace the plates I made out of the poly. I bought a bunch of 1"x1" (10 series) from 8020inc on ebay for a GREAT price to build the table out of. Almost 190 feet worth. Using the 8020 beams, I want to also incorporate a table saw that can be positioned under the bed of the router as a multi purpose table. Not sure yet how, but I'm going to try. Now that I have the basic XYZ router construction built, I can start measuring out specs on cutting parts for the table. 31" tall, 4" wider than the router and 1' longer to accommodate any future additions (like guards or dust shields). The computer/controller case is going to be mounted under the bed along the side just for that self contained aspect. I plan on mounting a swivel workstation at one end for the monitor, keyboard and mouse.
This whole project started because a friend of mine got a vinyl cutter and as I watched it cut out patterns, I got bent on making a CNC router which is basically the same thing but much cooler. Then as I started building it, another friend of mine asked if I could make it plasma cutting compatible... then the gears started turning. All these CNC machines are of similar design so why not. Don't know how plasma/steel sparks and aluminum will get along, but I'm going to have to upgrade to metal wheels I'm sure. The more I get into constructing this, the more ideas and revisions there are. I think I have rewired the computer/controller case at least 2 dozen times building harnesses and reconfiguring the locations of where to route the wires for optimal air flow and in case I need to service anything.
Its projects like this that are a prime example why tinkerers don't throw anything away... EVENTUALLY... some day.... we might use it. Old computer cases = prepainted sheet metal, I don't know how many old power supplies I hacked apart for lengths of wire and plugs. My basement has been turned upside down with old parts to complete this build. Very busy work. I just hope I can figure out the software as easily as building this.
Im just glad I stumbled across OPENBUILDS to really set this project in motion! The core components really made it easy to start and put the whole thing into perspective due to the "this is what you want, these are the parts you need to use". I spent weeks prior looking at different possibilities and configurations, the whole thing was a lot of noise. Find something one day, and the next something else, but they didnt fit together so start the search over. These C-Beams are excellent!
I'm still experimenting with how to complete the Z axis part. I initially built it as a fixed boom and was going to have the router move, but the more I looked at everything as it took shape, I decided to have the whole assembly raise and lower. If it turns out the whole assembly moving is too heavy/weak, then it is just a matter of turning the Z C Beam around and mounting the spindle clamp between the wheels and re-bolting everything together. I used the open builds double wide plates as a drill template to mark out the holes to make up some of my own plates to join the upper and lower V wheel plates around the X axis. I then made a pair of plates to mount the wheels to as intermediate plates between the C Beam Z axis and the X axis plate. On the Y plates, I drilled 3 sets of holes for the C Beams to have an extra bit of height over the work piece. By removing the bottom beam and placing it on top, and reassembling the X axis, I have a wider range of movement without needing to disassemble the whole router mounting plates. I left enough aluminum in the plates to mount dust collection hoses, limit switches and any other would be tooling. I have found that using the T nuts to mock everything up is a LOT easier than using the nylon nuts and also doesn't wear out the locking nylon. To get this far, I think I have assembled and disassembled everything a few dozen times to get everything to fit the best way I can. I might be looking at a wheel upgrade in the future as I have found if the wheels are pre loaded just ever too tightly, flat spots form and you can hear them as the wheels roll. ***** Do the Xtreme wheels do this as well??? ***** Having a multi wheel rolling assembly has proven itself its own set of challenges. The top set of wheels alone fit perfectly, as well as the bottom set with the eccentric nuts all at the same location. What I found is that even turning the adjustable nuts the same degree, feeling each one for tightness, by the time I got to the last one and checked the first one, the tension would change ever so slightly. I overcame this by tightening one wheel, rolled it back and forth a bunch of times, tightened the next and so on, they seemed to load more evenly throughout. I also found that even though the holes in the OPENBUILDS plates are very tight against the M5 bolts, loosening the top set after everything was assembled, THEN tightening them before pre-load also greatly improved equal pressure between the front and back sets. I initially had 8 wheels on top and 4 wheels on bottom but I could never get all 8 wheels to equally distribute pressure on the beam. I have opted to see how 4 on top and 4 on bottom of the X axis, 3 on each side of the Z axis and 4 on top, 2 on bottom on each of the Y axis plates. For the Y gantry plates, I have 2 fixed outer wheels and 2 on top and 2 on bottom eccentric nuts. I did this to help squaring up the X and Y axis and surprisingly enough, the 2 fixed wheels alone were perfectly square to the X axis beams so the adjustable wheels offered little more than setting pre-load.
I made a few mistakes when making my own plates. On the back X axis joining plate, I used 4 of the OPENBUILDS pre tapped holes but when marking out the line where the edge of the plate would overlap, I mistook the line as the center line for the first set of holes and wound up drilling a complete wrong set. After realizing what I had done, I took it as a blessing in disguise as I then used that set of holes to make the front connecting plate holes which worked out perfectly.
Another mistake I made was the holes for the Acme screw nut. I marked and drilled the holes and THEN realized I didn't have the bottom Acme screw plate on the C Beam which threw the alignment off about half a holes width. Easy enough fix, flip the plates and remark the holes. Which lead me to my next mistake. The 8 holes I drilled to mount that plate to the front X axis connecting plate were off ever so slightly (took 4 assembly attempts to figure out what happened ) So then I had to flip the front connecting plate SOLVED (you can see the plate laying under the green allen wrench next to the ruler-- the 3 larger holes are for the nuts to sit through and have access for adjustments if needed)
After I get everything assembled and functional, I plan on taking all the aluminum plates I fabricated and sanding them down and polishing them to a mirror finish and possibly clear coating the assembly masking off the wheel channels. Polished aluminum looks so good, the contrast between the black plates and wheels will give it a really sharp look... might even get the black T slot channel inserts (the wife wants blue though )
Got some more fabricating done on the gantry plate drive sprockets, some more wiring done on the controller/pc case, enough to do a communication test between the computer and the motors just to have one of the drivers smoke and die ~_~ Picked up some Rexroth linear bearings on ebay for dirt cheap I might use for the Z axis if what I've built isnt strong enough.
I decided to go with a dual #25 roller chain for the Y axis and found a set of sprockets on ebay that fit PERFECTLY in the C-Beam! There's just enough clearance to fit the chain and have it lay on the bottom of the inside channel away from debris. I used my trusty polycarbonate to build a see through template so I can check for clearances and it just looks cool watching things move around. It also made it easy to see my spacer was just a little too thick and needed to be sanded down to center the sprocket teeth in the channel. For the motor mounting, I used the OPENBUILDS motor plate as a center hole punch guide then used the polycarbonate "template" to transfer the holes to the aluminum. I found a hole saw that fit the NEMA 23 motors face plate circle but quickly found out that the saw wasn't exactly designed for aluminum (extremely LOUD screaming drill bit) but it worked with a few squirts of WD-40. The polycarbonate and the aluminum aren't the same thickness (the poly is .224 and the aluminum is .252ish) but it allowed more threads for tapping and didn't exactly alter the spacing.
After I fit everything together to check clearances, I shaved down the idler spacers so the teeth were centered in the channel and lined up the drive sprocket between the 2 idlers. The way everything tucked into the C-Beam almost seemed like it was made for it.
#25 Chain Sprocket Idler Sprocket 20 Tooth 10 mm bore | eBay
The drive sprockets:
#25 Roller Chain SPROCKET 9 tooth bore 6 mm | eBay (*note: my stepper motors are 8mm shafts so I used a letter "O" drill bit which is 8.0264mm and took some filing to get it to snugly fit over the shaft*)