[swatkins]

Hey all, hopefully somebody out there has axperienced this problem...

We have an EZ Trak with a 4in Acurite scale on the Z axis. The machine runs fine with cuts in plastic, but when cutting aluminum(at recommended feed n speed) the Z axis position jumps around on the DRO. The actual position of the quill does not move though. I cleaned up the scale a few months ago to no avail. I tapped on the side of the ball screw housing with a small mallet this morning and sure enough the vibration seems to be the culprit. Any suggestions?

[NC Cams]

There were several Extraks and they had some real jerky jerky, Rube Goldberg drives attached to the Z axis - the one we have is a vertical external ball screw with a right angle servo drive attached to an outrigger arm attached to the nose of the spindle - Talk about RUBE.

At one point, when/if you had a true 3 axis version Extrak, BPT actually retrofitted a different linkage/drive arrangement to your machine go get it to work. In light o BPT's demise, forget that.

Point is, Extraks with the outrigger arm do not have sufficient rigidity to hard core 3 axis machining. PERIOD. There is an out fit out of Kanas or IOwa called Elrod Machine, who has a ball screw drive kit that bolts to the front of the spindle column and does a 3rd axis drive that is rigid. and doesn't rely on the Acurite scale for 3D feedback, They use the tach encoder to do so AFIK.

If you have a BMDC based control, there are ways to "tell" the controller that you've changed the drive and have it respond accordingly. The drive change is a bolt on, the software changes are NOT plug and play. You need to find some one who KNOWS the BMDC, however, to affect this change or you can mess ith it yourself if you know how to change the parameter settings on/in the BMDC..