Aligning the bar feed on an automatic lathe: A case study using the Easy-Laser® E940 Machine Tool system
Recently, I&E Central (along with a service partner) used the Easy-Laser E940 Machine Tool system to perform alignment on an automatic lathe similar to the photo above. The lathe has an automatic feeder for 20’ sections of tube stock which are supported alternately by V-rollers and then clamped by “steady rests” while being machined. The objective of this job was to have the stock in perfect alignment with the rotational center of the spindle when supported by either V-rollers or the steady-rests. In addition, there is a pusher system that advances the stock into the collet. The movement of the pusher needed also to be aligned with the spindle centerline. This was a challenging measurement made possible by the availability of a spindle laser that could be directed back through the collet.
A laser transmitter was mounted in the spindle with its beam directed through the collet. The laser was adjusted to the rotational centerline, then the spindle was turned at 200 RPM for measurement. In this way, the beam precisely marked the rotational center along the entire length of the machine.
The first measurement was the location of the center of each steady rest. A laser detector was mounted on a short piece of stock, which was locked in each steady rest for measurement. A center of circle straightness program was used to measure and adjust the position of each steady rest. These were adjusted “live” so that each steady rest held the stock in line with the spindle rotation.
Once completed, pk-pk deviation in the vertical plane was 0.0095”, in the horizontal plane it was 0.020”, well within the customer’s desired specifications.
The next step was measuring the straightness of travel of the pusher arm relative to the rotational center of the lathe. This was accomplished by grasping a similar piece of stock with the jaws of the pusher, then using the same program to measure and adjust its true position at 4 locations along its travel.
The final adjustment involved adjusting the V-rolls to support the tube stock in line with the center of rotation. This adjustment was actually done without the laser. A full-length piece of stock was secured in the collet with the other end supported by the pusher. Each V-roll in turn was adjusted with shims so that it supported the stock precisely on the centerline. The customer tells us that the machine now runs smoother than it ever has.
The measurement and alignment of this machine section were never performed by the customer or any service contractor in that they had no way to make the measurements. The power and flexibility of the Easy-Laser E940 system made this a straightforward job that was completed in 1 day.
Special thanks to Bob Dunn with I&E Central, Inc. for sharing this case study with us!
Alignment, Articles and Case Studies by Ana Maria Delgado, CRL