CuttingTools
04-29-2007, 08:39 PM
I have A cnc TAIG Mill with the 18" Table, This machine has the CNC Leadscrew nuts. I am getting backlash that I just cannot tolerate as I machine many parts that have bearing fits machined into them. Has anyone installed ball screws on the Taig mill? If so can you elaborate on the process. I am open to listening to any ideas on correcting this problem.
Scott
edferg
04-30-2007, 12:56 AM
I would ask here:
http://groups.yahoo.com/group/taigtools/
On my Taig CNC mill I get 0.003" backlash, which from reading the group, seems typical. If you are getting more than that, there are ways to isolate and fix the cause.
I've seen a couple of posts from guys who have converted Taig mills to ballscrews (search the group above). From their descriptions, it is not easy or cheap. If it was an easy retrofit I would be interested myself.
Ed
Stepper Monkey
04-30-2007, 06:40 AM
What do you consider acceptable? I can get .002" or so on mine, and like Edfurg saud .002"-.003" seems typical and realistic.
I looked at mine to do a ballscrew conversion on, but it looked easier to me just to use the Taig to simply build another machine from scratch than to modify the stock Taig. Now I have the Taig for most use and a homebrew with ballscrews that I used the Taig to build. Ironically it cost about the same as modifying the Taig would have, as the major cost is in screws and a/c bearings. Easier too, I think.
I also scored a seriously beefy used Parker Daedal unit out of a laser optics facility that holds 1.3 micron, or .000051", but that is just getting stupid. It only has a 6" x 6" working envelope, But ground ballscrews and six(!) encoders. Its for sale cheap if you really feel the need something that blatantly insane, or just shop around for surplus if you are in a tech-rich area for something similar.
edferg
04-30-2007, 09:47 AM
Stepper - Have you posted a description or photos of your mill?
Also, send me a PM with details on your Parker Daedal unit. I have an application for a small working envelope mill for engraving.
I agree, It would be just as cheap to build a mill using ballscrews. I wish Taig offered a ballscrew version.
For a turn-key system, the Syil Products X2 and X3 are the lowest cost ballscrew mills I'm aware of: http://www.syilamerica.com/products.asp
Ed
GammaWill
05-04-2007, 02:04 PM
I have a brand-new Taig 2018CR-ER and after doing the disassambly-and-nut-adjust featured on Nick Carters Taig pages, I got my backlash to .002".
I typically mill symmetrical 1" mold cavities 1/4" deep in aluminum using a 1/32" ball cutter, and the backlash is not noticeable on my resulting parts.
Just the same, I tried using the backlash compensation available in Mach3 which dropped the backlash to zero, but it added a crazy ramped decelerator when the axis changed direction, which tended to stall my steppers when used with my gcode and the acceleration I had set on my axes. I couldn't get rid of the funky behavior, so I abandoned the backlash compensation altogether.
It is kind of funny - my guage measures thous on a big dial, and a deflection of .002 looked HUGE on it. At first, I thought "Oh Noes!", but then I stopped and asked myself "Will, is it *really* that bad?". It wasn't. :)
CuttingTools
05-07-2007, 06:57 AM
I worked with the Taig over the weekend and I was able to get the backlash to .002 by adjusting the lead screw nut. My screw does have some wear in the center as it is now tight at both ends of the travel. All the parts I machine are small so this is not too much of a problem. I am going to order new screws and nuts for both the X and Y axis< when I install these I am going to add a bijur automatic oil pump so I know that they will always be well oiled.
Scott
edferg
05-07-2007, 10:37 AM
Give us an update when you install the new parts. I ordered a new nut for my X axis but have not installed it. The brass leadscrew nut has a boss that appears to be press fitted into the mill. Not sure how to remove it and align the new one.
Ed
cartertool
05-07-2007, 04:04 PM
You can press it out, or carefully use a soft punch and punch it out.
The brass leadscrew nut has a boss that appears to be press fitted into the mill. Not sure how to remove it and align the new one.
Ed