Ballscrew Comp table.

[FT_factorytuned]

In need of some uh, advice, on building the ballscrew comp tables. I have contradicting information on how to do this. The milltronics factory comp table is different than how I've been told to build the tables.

exp.:

-15.50000 -.00015( -31) Factory Build example.
-15.49985 .00015 (-31) How we've been told to build.

Which is it?

Also another contradiction is ascending vs. descending.

Would appear as though the Factory tables are ascending
exp.:
-1.0000 -.0002 ( -4) ascending least error (Factory Method)
-1.0000 -.0020 ( -4) descending greatest error (Method in current tables)

Which is it?

We are pulling the numbers from the CMM using ascending least error "or as measured".

exp:
-25.0000 -.0032
-1.5000 -.0003
-1.0000 -.0002
-.5000 -.0001 etc.... But with actual numbers from CMM data sheet.

Which is it?

Thanks.
FT

[jpawelk]

The Factory method of ball comp table is the only method that can be used. Please see the attachment, it is a ball comp table for an X axis on a 3 axis machine.

[FT_factorytuned]

Thanks for that.

That's what we're doing. That is totally contra to the factory ball comp table. Which is from the original printout and PARMS diskette that shipped with the tool. That's descending greatest error. When we use this method and build the new comp table we get a .003xx under run in overall table travel. When BS comp is off we get a .005xx overrun overall. X ax 25" (Partner1).

I'm going to load the tables off the original parms diskette, and then run a ref plate, CMM, check. Then see where it is.

I was told to add/sub the difference etc.. But the original table uses a signed method and leaves the distance as a set distance. -15.0000 -.0015 to correct for overrun etc.. Original Y table, where under run,(8.0000) -7.99912 .00088, which would add 88 ten,th to correct for under travel.

We're running Ti compressor parts and the machine has been highly tuned for these parts but this was a perplexing question that cropped when the first large part came out oval .002xx AFTER all the tweeking. I was told when tuned should be able to hold .0005/.00025. over travels. Small diameters are in spec, well, we'll say within draft tolerance. But the large parts 6"+ are out.

Was much worse before .006xx+. I'll figure it out. In the mean time any addy's are welcome. Advise is a wonderful thing. Don't want to bug Milltronics about this too much as they are a helpful bunch, but look to us to be competent.

FT