deviation in perpendicular direction
deviation in perpendicular direction
Hi to everyone,
I have a strange problem with my machining center. I have a horizontal bed type machining centre (traveling column), and I’ve noticed an error when I move the ram.
I move the ram to the outer position (up to the final of the course), and the tool tip goes straight, but when I reverse the direction and I start moving inside the ram, the tool tip has a displacement in the X direction (the direction of the bed), and the tool tip goes inside in an inclined straight line.
The machine tool has a direct drive with a rotary shaft in the ram, and a fixed nut in the carriage. I don’t know if it is an error of guides, a drive problem, if it is because of any existing clearance …
As I think that you have more experience with machine tools than I do, I would like to know whether any of you has noticed any similar problem with any machine tool, and if this is the case, which problem you detected and how did you solve this problem.
Thanks in advance,
Best regards,





RE: deviation in perpendicular direction
RE: deviation in perpendicular direction
The problem is in the movement of the ram along the slide, the movement in the y axis (see picture). While the ram is moving in the positive y direction it goes straight, the movement is ok. But when I reverse the direction, there is a deviation in x axis and the ram moves back in a stright line, but not in parallel to y axis.
I don't know if I've explained it better this time. I hope so. I don't think that anything is bent. The movements (both) are straight.
Looking forward to your help,
Thanks in advance,
RE: deviation in perpendicular direction
RE: deviation in perpendicular direction
As BT mentioned, check your gibs or their equivalent, and also check your spindle quill or ram actuation parts to make sure something has not come loose or has broken causing a side-loading while traveling.
These things can be difficult to track down when an obvious problem does not present itself outrightly.
Good luck.
It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.
RE: deviation in perpendicular direction
RE: deviation in perpendicular direction
Manual machining only - I have NOT programmed automatic mills and automatic milling machines! - but I've seen great differences "climbing' in the feed direction compared to the opposite: the "Pull" of the tool differs each way, and so the pressure of the tool against the milling head restraint (both gibb - the sliding machine restraint against xy - and the milling head clamp (milling head rotation restraint) may move more when they resist rotation of the head one way compared to the other direction of feed.
At home, my own (very small, very old) mill performs terribly when I feed opposite hand.
RE: deviation in perpendicular direction
Get a precision square and indicators and verify the alignment of the axis. If your machine is as large as shown you will probably need to contact the manufacturer and have them fix the problem. The cost will be substantial if the axis/roller packs have been damaged.