Haas with Hiccups!!

[WOLOG]

Has anyone run across a time when you would have to re-run a part (not moving the part just rerun the program from the beginning) and the second time the part was machined, it was way out of tolerance? I can not figure this out at all.
The part did not move at all. All I did was reset the machine and run the program over again. My slot came out 0.060" wider than the part before it that ran through the program once. Ever heard/experienced this on a Haas mill?

[WOLOG]

Just in case. I am not making this up.

[mactec54]

Hi Wolog
I don't no the Haas control,But what would you press the machine reset button for this could be your problem if you have to run the same program
a lot of times you should have a M30 a the end of the program this will
take the program to the start as soon as it has finnished. If you press
the reset you would most of the time have to rehome the machine like
I said I don't no the Haas control

[Geof]

It did part one okay.
Then you ran part two twice and it came out with the slot 0.06" wider than part one.
What about part three?

[WOLOG]

After I noticed that the two parts that were machined twice were out of tolerance, I shut down the job and tried to call the applications engineer with the local HFO. As long as the part is machined once, the part is fine. By the way, the job involves a right angle milling head inside of the part. There is a picture of a test part in the Haas forum section about programming a right angle head . The picture is on page two.

[SORCHEROR]

i think your getting flex when you machine it the first time,when run again theres no stock so no push and the slot if cutting bigger,just a guess with out seeing or knowing what your setup is,but it make sense if you think about it,is the slot being cut in one shot at a fast feed?

[SORCHEROR]

hass machines dont need to rehome after stopping a program and pressing reset,i do it all the time

[SORCHEROR]

another thing it might be is a G91 code,incremental move,i use G90 abosolute move,if you stop a program it doesnt go back to x0,y0 so it might not start up it the right place with g91,with G90 i can start a program from any position i have the table at,are you using G54 work offset?your using a right angle head so that changes thing allittle,is your slot wider too?or just longer?and is it longer in only one direction,like your out of position?next time your have to stop one,send the machine back to its starting spot,bet it will work than

[WOLOG]

Good point. I know that the spindle will orientate as needed, but only the encoder is keeping it "locked" It still seems like an error would occur during a actual cut rather than air cuts. Sometimes my bright ideas cause more problems than I really need.

[SORCHEROR]

could you post the G code?i would see it right off
thanks,steve

[SORCHEROR]

its because the machine isnt in the proper starting position,im almost certain of it,im used to G90 and no right angle head,so i can start from anywhere and it always work off of machine zero and my work offset,if i could see your program id know

[WOLOG]

The slot is only wider on the y positive side. The length is fine. I am cutting an oblonged pocket the is .470" wide x .560" long. Full radius on each end. I will post the code in the morning. If I remember right, I shouldn't have a G91 anywhere in the program. I am starting to think I may have problem with the processor or the motion control board. Yesterday afternoon I had an alarm that said there was a potential problem the MOCON. i don't remember the exact alarm number.