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Haas servo bar 300 not pushing correct length


Aug 27, 2002
West Unity, Ohio
Hey everyone. I’ve been searching for answers for this and haven’t found anyone with my exact problem, or any answers that work.

We have a Haas ST 30y and a Servo bar 300 at work. We set it up once and ran 150 good parts. I broke it down for the next job and now I’m getting incorrect push lengths. I set it up per the manuals instructions, Q6, Q4, Q2, etc. fill in 3100, 3101, 3102 etc. What’s weird is that the first push is correct at 2”, only varies by a couple thou. Any push after that will be 1.84 - 1.85”. The part length is .840, I’m using a 1/16 part off tool and I add .05” for facing, so #3100 is .952. #3101 is 2” and 3102 is 2”. We couldn’t figure it out so we fudged the 3100 number to make each push the correct length and we ended up crashing a $600 drill because it pushed out way too much after loading the next bar.

Something else I’ve noticed is the #3110 value “current bar length” is very inconsistent. On a 48” bar I was getting 45.87-45.89”. On a 36” bar I’m getting 33.715 - 33.957”. So both bars it’s about 2.2” off what it actually measures. Is all of this due to a faulty sensor? Please help because Haas is completely useless! Thank you!

I'm still wondering what Jon is talking about, but in the mean time I will address your Q:

Again - IDK about your loader/feeder, but on any of ours, I have them set to load slightly beyond what you need, and you run a "Top Cut" routine, where you take your cut-off tool and cut off whatever is beyond Z.025 or whatnot. This would be in your subroutine for the loader.

Ideally you would only have a slight amount cut-off. A .025+ disk is nice to have as an assurance that you are loading far enough to not be making junk every first part, but also so that you are not wasting much material as well. But if your prox doesn't see your bar for a bit, and it pushes it too far, then your cut-off will simply true up your bar and you are out 3" of material - rather than your $600 tool.

Now, with that said, a face cut would have put your problem into a $100 tool rather than a $600 tool.

In production, I always feed to a stop. That feeder is not 100% solid and it doesn't run on a ball screw.
You likely have a parameter on your feeder asking if you are feeding to a stop or not.

If your set-up guy set it up that way, from my experience, either he hasn't had to try to make that work in production, or he lives in a much more perfect world than I doo.


Think Snow Eh!
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