The day I figured out I was climbing my tool offsets instead of resetting them

I ran a Haas VF-2 for like three years straight, making production parts for a shop near Toledo. Every morning I would load a new vise setup and just adjust the tool offsets up or down based on my first cut measurement. It worked fine for single parts but one Tuesday I had a run of 50 aluminum brackets and the first 12 came out undersized by .015 on the hole spacing. I was pulling my hair out checking the program and the fixture until the old timer Mike walks over and says "you ever zero your offsets instead of chasing them?" Turns out I had been stacking errors from previous jobs into the offsets for months. That little habit was slowly drifting everything. Now I reset to machine zero every time I touch off and I havent had that issue since. Anyone else ever realize they were doing a basic setup step totally backward for way too long?

2 comments

2 Comments

wesley_grant3327d ago

Oh man, that hits close to home. I did the exact same thing on a old Fadal for about two years before I figured it out. I had this one job where I was machining steel plates and kept having to tweak the Z offset by a few thou every cycle just to hold tolerance. After about the 50th part I realized I had drifted the offset almost .040 from where it started because I was always compensating for tool wear instead of just touching off fresh. When I finally zeroed everything and started over, the first part was dead nuts on. I still feel stupid thinking about all those hours I wasted chasing ghosts.

karenw2327d ago

Oh jeez, I did something similar on a little Prototrak mill. I kept bumping the offset up to fix a backlash issue and ended up with parts that were all over the place. Finally just zeroed everything out and started fresh - best decision I ever made.