Shifting origins

[Lepage]

Hello everyone,

I have a Brown & Sharpe MicroVal Pfx with PC-DMIS 3.5 MR2 software and have the following problem. The origins (x axis) of all of my programs seem to shift between 0.2 to 1mm after the DCC alignment, without any change to the fixture or anything else. I’ve even had a shift in the origin (x axis between theoretical and actual results) of 0.3mm with the same work piece that I had re-measured with the same fixture 10 min. later. Other axis deviations are no more than 3-4 microns (mm)! Has anyone had anything similar to this? Is this a mechanical or software problem? Any help would be greatly appreciated!
Thanks in advance.

Best regards

Lepage

[ag162]

Be sure to check your feature locations in the DCC mode. It could be something simple. F9 the feature.

A.Gore

[Paul Sarrach]

You stated origins? What do you mean by that? Your A_B_or_C Datums?

[\v/inston]

its most likely someting simple that is out of order, causing it to fluxuate.

[Underspec]

Here are some things I've ran into with fluctuating dimensions.

1) The Probe was lose on the module. Check to see if it's tightened.
2) Probe was a little bent. Check to see if it's straight and recalibrate.
3) Make sure you're using a correct force on the module? Not sure what material the part you are measuring is and what size probe you are using.


All these sound like noob help but it helped me. Goodluck.

[Jeffrey Lovely]

I have had the tp2 go bad
check one side 0.0 then op side off 1 mm diff direction

[BSchwark]

Are you aligning on a fixture and measuring the part or aligning on the part in a fixture?

BS

[Paul Sarrach]

Once a had a loose stlii, It took me all day to figure out what a doofus I can be.

[Lepage]

Paul, I mean the origin of my DCC alignment.

[Lepage]

BS, I'm aligning a part in a fixture.

[cmmguy]

Do your datum setup one component at a time, Don't measure all of the features first and then go back and do the Datum setup all at one time.

eg. (simple)
measure plane, Level, set origin
measure alignment feature, align, set origin
measure third axis feature, set origin

I don't know if this is your problem, but I see it done all of the time and cringe at the potential error.

Anyway, happy green day....

[tking]

CMMGUY,

I agree, the slow plodding method saves time (time after time). You always know the line is on the plane. The circle is seen in that plane. On and on.........

Terry King