Haas VF-9 Ball screw issues
We have standard 2007 VF-9/40 in our shop and in last 1½ years we have had both X and Z axis ball screws replaced. X-axis went first, it looked like ball nut failure. It got noisier and noisier during rapids (rattling, popping and whining) and finally there was about .30mm backlash. When Haas service man pulled the screw out it was still very well oily and screw itself looked fine (no pitting or anything) but the ball nut was very loose and rough running over whole travel.
Fast forward one year and Z-axis got noisy too. But this time the noise was more like grinding and groaning. And it was loudest at where the machine does 99.9% of its cutting (job we run is almost entirely drilling and tapping.. A LOT).
Again. Service guy was called and when he pulled the Z screw out.. well theres your problem. Serious flaking and pitting. Nut was somewhat rough running over whole travel but it was very bad at certain points. There was also plenty of oil on the screw so it was not oil related problem. We use only Mobil Vactra 2 and oil consumption seems to be constant.
Z-axis screw looked like this:
When first screw went we had haas tech to inspect and flush whole oiling system and he also fitted new metering units just to be sure.
So. Is this normal life for Haas ball screws or are we just unlucky? We run this drill/tap job in 3 shifts and make several 1000s of work pieces in year and it does use almost every millimeter of XY travel this mill has to offer. Repairing this machine is eating our income..
Kind of hard to say what is normal life since nearly each and every machine does not run the same work wise.
Originally Posted by Harter
With regards to the Z axis ball screw however, you said that you run 3 shifts, making thousands of part a year, primarily drilling and tapping. To me that sounds like a lot of short movements in a relatively small area of the ball screw.
Did your tech give any indication of what the cause of either one was?
I guess time will tell for how long the new ball screws last.
Tech wasnt able to pinpoint other reasons than heavy use. We also have couple Quaser brand machines which have been running 2-3x longer than this haas and still have original screws..
We have two VF5-50 Verticals, both new in 2006. To date, I think we have replaced two Z-Axis screws, and about 4 Y-axis screws between the two machines.
Haas has told us from the beginning that the reason is the gray iron we machine. Funny that we have a whole shop full of CNC's that all machine gray iron, and have maybe replaced 2 ballscrews total in the last 15 years on these other machines.
Originally Posted by Harter
We run only plastics and aluminum.
try barnes industries, inc. free evaluation top notch in the industry. Ball Screw Reconditioning, Retrofitting, New Ball Screws and Acme Screws- Madison, MI- Barnes Industries, Inc.. ( no affilliation, just past experience with some mazak rebuilds)