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trunnion adjustment question

astropaulo

Aluminum
Joined
Mar 22, 2013
Location
Westlake Village, Ca
Hi All,

Fairly new to Trunnions. When it's at A90 and I face the part, flip B 180 and face, the finish dimention is undersized. Checked tool offsets and they are all good. Would the offsets on one of the axis on the trunnion effect this? Sure I can adjust for it in CAM but wondering If I messed up on a setup.

Thanks

Paulo
 
Is this a bolt on trunnion or built in?

For a Haas bolt on (TR160-Y), here's my procedure:

1. Align the tilt axis with a linear axis, within a tenth, or better if possible.
2. Find tilt axis zero / level. Adjust this rotary axis offset to zero best you can. Best I was ever able to get was about .0004" across the platter.
3. Check tilt axis 90 degrees, should be straight up and down. Split the error between this and level.
4. With the tilt back to level, put a vise on the quickpoint plate and indicate the rotary axis straight, set work offset zero.
5. Take the vise off, and probe / indicate the center bore into one work offset, rotate 180 degrees, do it again into another offset, average, put the result into the work offset I'll use.
6. Put a collet holder on the quickpoint plate, put in a 1" round of aluminum, tilt over 90 degrees, probe the top of the round, subtract the radius, store in work offset.
7. Touch off a new endmill, face mill a flat, rotate 180 degrees, repeat. If I milled at Z+.4000", it should measure .8000" across. Adjust the Z offset to bring the error to zero and check again.
 
Hi All,

Fairly new to Trunnions. When it's at A90 and I face the part, flip B 180 and face, the finish dimention is undersized. Checked tool offsets and they are all good. Would the offsets on one of the axis on the trunnion effect this? Sure I can adjust for it in CAM but wondering If I messed up on a setup.

Thanks

Paulo

how did you determine the center of the axis?
 
How did you measure the Z position? With one of these tools that was "good"? Or with your spindle probe?

If spindle probe, when was the last time you calibrated the length? And machine/spindle temp at that time? Often times this goes overlooked...

Not necessarily the tool length changing, but due to the machine's thermal growth or shrinkage, it can change up to a few thou throwing out your z-offset, depending on your shop environment, or even just the spindle temperature. When setting a 3-axis part, no big deal, just adjust your workoffset to get the right thickness.

This issue comes up in my shop once in a while... "hey why do I always have to adjust my workoffset by ____ after I probe it?" Well, the probe is just a reference tool.. but automated. If that reference length doesn't match what the machine thinks it is, you're not going to set the correct Z position.

But when calibrating (and updating) something more important like a rotary center, more care needs to be taken. Depending on the machine temperature, this can float all over the place. My shop has large temp swings and on my UMC things can move up to .003"

When you're facing the sides of a part, you need to be more precise with your offsets since you're effectively taking a radial cut, similar to a lathe. The depth of cut on one side is half of the total change of the thickness (or diameter)
 
Checking it with a probe. Thermal growth is probably some of it, I need to be more careful in having everything up to temp. It's about .003-.004 under on a side.
Come to think of it I think I had my set up more accurate using a 3d haimer. Better check the probe. What is interesting is it only happens when the platter is at B0. The B90 operations it is pretty close, maybe a thou or 2 under per side.

Another question, I got my trunnion used. When I home it the tilt axis usually homes within a thou but the platter is in a range of about 5 degrees. Once I set the offset for it i'm good it's just every start up I have to set it. Not normal? I know I should just take it in but I don't have 5k burning a hole in my pocket!
 








 
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