I purchased a Taig cnc ready mill (2019CR) and the 3-axis servo system from IMService.

I have been learning,tweaking and tuning on this setup for almost a week now. I have made a few cuts in aluminum with my 1/8" endmill. Taking .06" deep cuts at about 30 ipm leaves a nice finish with the spindle running at 10k rpm.


Looking at the X-Y table/saddle on my Taig I see there is not much extra room for mounting ball nuts. Same goes for the Z axis.

The thought of almost no backlash for extended periods and maybe 2x the rapid speed has me thinking this would be a nice addition.

I have searched here and google and have not yet been to the yahoo group. From the ball screw/nut dimensions I have seen it looks like I would only be able to fit something in the 5-10 mm screw diameter range.

I was hoping to find some leads here. Any advice or perspectives would be much appreciated. Thank you, Chuck.



I took some short webcam videos of my setup (running dial indicators in X and Z after 'tuning'

These are zipped movie files about 2-3 megs. I was able to DL these at 3-400KBs and they only took a minute or two. It seems I needed to DL the windows media encoder to get these to work,go figure..
http://home.comcast.net/~singl3guy/encodingcnc1.rar
http://home.comcast.net/~singl3guy/X.5at100000SPS.rar

Somewhat related...
The only reason I am searching for mini ball screws instead of making parts is that one of my servo motor encoders arrived with what appeared to be shipping damage. I called IMService and they sent another complete servo assembly that day. This is unfortunate, but IMS was very easy to work with and the new servo assembly should be here any day. Other than that the system is working nicely despite my attempts to destroy something by running the system with a visibly damaged encoder. Once the damaged motor/encoder recieves a pulse/step signal it just keeps going. ESTOP ESTOP ESTOP!! Doh! thats gonna make some backlash.. Did I mention Deskcnc did a great job on their fault system?

I've also got a Taig with servos from IMService, but I used counterweighting to eliminate all backlash. Since the Taig uses large/robust feedscrews, loading the X and Y axes with 7 pounds isn't a problem. I've attached some pictures of the setup. This setup quickly clips onto the mill -- and can also be removed in a jiffy. It evenly weights the X and Y axes along the feedscrew axes. I also added a separate 5 pound weight to eliminate the offset mass of the motor on the Z axis. This allows for much smoother Z axis travel. This setup is easily repeatable to a tenth -- and I've found that the feedscrews are very linear along their travel.

-David

That is a nice setup. I'm sitting here trying to wrap my brain around the counter weights and the pulleys on the X-Y. The Z axis makes sense to me. It will take me some time to figure out that X-Y system though :confused: 1/10,000 repeatable sounds awesome, heck I'd have to get better calipers, my digit-cal will read 10ths..5 at a time heh.

How much travel do you estimate between tightening the preload on the nuts? I was thinking about calling Kerk motion products to see how much they wanted for some of their screws/nuts, but they probably want almost as much as ballscrews would cost. They are able to cu$tom cast some kind of low friction anti backlash nuts with low/no maintance. http://www.kerkmotion.com/products/lead-screw/lead-screw.asp

Looks like you have made some other upgrades also. Is that a 1/3 HP motor I see powering the spindle? I like the 1"? standoff on the Z axis carriage also. Are those direct drive brushless servos? If you have the 2nd gen controller I bet you can achieve some nice rapids. 60+ IPM? For some reason I'm thinking faster rapids would wear my nuts down faster, but 60 IPM would be nice I think. I am maxed out at about 40 IPM with these belt drive reducers. They take my servos 3K RPM down to about 1K.

Thank you for sharing, I think I will try something like that before looking to replace/upgrade and of my screws. After all my Taig is brand new (and I just dropped $1300.00 on A RhinoCAD/CAM bundle). I think the next upgrade will be some nice 4 amp servos maybe. Are you still using the stock torque couplings? That is something else on the short list. The fact that the mill came with 4 extra of the little plastic tubes has me expecting those to be the first to go. Nick Carter also mentioned he had upgraded his if I remember correctly.

Thanks again for sharing the nice setup. Chuck.