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X3 build - Kflop/Snapamp, Keling servos, AC servo spindle drive, cncfusion kit...
I started this build 2 years ago and had to abandon it after just a few weeks. It's now officially resurrected and I'm ready to start posting now that I'm making some real progress and have the time to dedicate to it. If interested, here's a link to the original build thread:
http://www.cnczone.com/forums/showthread.php?t=40861
I've made some changes to the build that are worth mentioning, mainly switching over from the Grex G100 controller to Dynomotion's Kflop/Snapamp combo. I decided to go with the Kflop controller because it looked like a promising USB controller w/ closed-loop servo capability and the Grex felt like a dead-end technology since the development and support had all but vanished. I'm very glad I did because (as most of you here probably know) the Grex development was dumped shortly after. :|
After only 15 minutes on the phone w/ Tom from Dynomotion we had one of the keling servo's running in closed-loop mode on the kflop. I then decided to pull off of the x3 build and focus on retrofitting a Denford MiracPC lathe that I picked up from Reliable Tools using the kflop controller and a couple of used IMS drives from ebay. I'm actually using the same kflop controller to run the lathe and the mill since it supports up to 6 axis.
I had zero electronics experience and Tom practically walked me through the entire process so without him it would have never became a reality. Besides being extremely knowledgeable his support was way beyond anything I have experienced from any other vendor I've dealt with so far. In fact he helped me with other vendor's products when I could hardly get a response from them! (Thanks Tom)
Moving forward... the first agenda was to bore out the gearhead couplings that were too small to fit the keling motor shafts. I had to bring them up to 1/4" from 3/16" and I ended up using 3 bits for this job - the first two were standard drill bits and the last one was a 1/4" milling bit. I had to break out the fogbuster coolant for this or it would have never worked! Whatever treatment those couplings had gave it some serious hardness!
The first coupling didn't come out so well since I used 3 standard drill bits (before switching to the 1/4" milling bit) and the diameter was too large. The fit wasn't even close to snug but I managed to get it torqued onto the shaft at least. The second one came out better since I switched to the milling bit for the final pass but it still had plenty of slop when fitted to the shaft. The last one came out very well and had such a tight fit that there was a slight pop from the air suction when trying to slide it back off the motor shaft. Very happy with that one. I guess I got a better feel for aligning the drill bits on the lathe and also the speed and feed rates.
I then turned some motor mounts from some 1/2" Al bar stock which were the first parts I made on the lathe (or on anything for that matter!). I had to drill and tap some 4mm metric threads on each end. These all came out pretty well and I learned a lot about speed, feed, and d.o.c. since I just jogged them out by hand using the kmotion software with on-screen pendant keys. I actually started coding some gcode after getting bored a few pieces into it which worked pretty well and saved a ton of time.
For the most part all of the mounting of the motors and gearheads to the cncfusion kit went pretty smooth. I used the drill press and a milling bit to mill out some pockets into the backside of the Y axis mount that sits flush on the side of the table and drill out the threads for the top two holes to get the Y axis mounted. I had to do the same to all 4 of the mounting holes on the Z axis plate.
For the X axis plate I ended up tapping and force-threading some 4mm metric screws into the motor mounts and then cut the heads of the screws off with the lathe (see pics). This gave me a threaded end on the mounts that I could thread into the top two holes on the x-axis mounting plate.
All 3 axis are mounted and aligned and working well. I used a cordless drill attached to the encoder shafts to drive the axis' and they appear to be functioning in good order.
Next up are the gas struts to support the head weight...
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Denford MiracPC slant-bed lathe
Yeah, it's a slant bed lathe by Denford. I picked it up off ebay for a really good deal about a week after I bought a little 7x10 HF lathe. I quickly realized how much time I could save by starting with a decent cnc lathe and upgrading the electronics vs trying to build one from scratch. I ended up selling the 7x10 unused and I'm really glad I did cause the Mirac PC is a way more capable and far superior machine in comparison. All the hardware included with the MiracPC is top of the line and I tried to copy it wherever possible for the x3 enclosure build. 90% of the hardware used on the x3 enclosure is high-end stuff that I got for dirt cheap on ebay. Patience is the key there. ;)
Since the lathe is a 1994 version that ran off DOS I ended up scrapping the controller altogether and retrofitting some new (used) drives controlled by the kflop after failing to get it working on an old DOS computer. It appeared to be hardly used when I picked it up so I was really happy to say the least.
In the pics you can see the original control box before I added the bottom plate and mounted all the new hardware to it. On the side of the box you can see the break-out board that connects to the kflop controller via a serial cable that is now mounted in the new x3 enclosure. It looks all nice and tidy now but check out the nightmare photo (2nd to last pic) of the work in progress! In the last photo you can see the current temp setup I'm using now to make the x3 parts.
I got the idea to use that cable ducting for the x3 enclosure after retrofitting the lathe and being so impressed with how well it worked for cable management in the lathe controller box. I picked up a long stick of it from Mouser. The design is exactly like you explained.