Measuring a simple hole for a (dumb) teacher...

[guillaume_martin]

Hello,

I'm teacher in france. I arrived in a school where a CMM is installed with PC-DIMIS... but nobody knows how it works...

Si, I'm trying to use it, because it is very interesting for the students. But my beginnigs are not very successfull http://www.pcdmisforum.com/images/smilies/confused.gif
!

I reached to measure my probe : OK : 2 mm.
I measured angles : OK.
Then, I wanted to measure the diameter of a simple hole, what is 12 mm wide.
So, I measured the cylinder, but PC-DMIS answered 8,05 mm...

Do you know where I could be wrong ?
Where could I find a A to Z documentation to measure the diameter this simple hole ?

Thank you very much for you attention !

Guillaume MARTIN

[Matthew D. Hoedeman]

Look at the feature (the data for the hole) in the edit window and look and see what type of hole it says you measured. It sounds like it thinks you measured a STUD instead of a HOLE so it will say OUTSIDE instead of INSIDE. Simply highlight OUTSIDE and hit the F8 key to toggle it to INSIDE. You may have to re-measure it to get it to give you a good reading after you change it. To do that, simply place the cursor on any line of the feature and hold teh CTRL key down and hit the E key. It will then prompt you to take hit 1 of 4 (or however many hits you took).

[JamesMannes]

Depending on the version you are using these tutorials may help you start correctly...

http://www.wilcoxassoc.com/Usersarea/tutorials.htm

[John Kingston]

Has the probe been calibrated? What size is the ball on your stylii?
I don't want to sound condescending, but if you have no experience at all, you may not be aware of the fact that the software needs to compensate for the size of the ball. If someone has change to a larger stylii since it was calibrated, that may explain the size difference.

[bw_bob]

What everyone has said previously. I'm impressed you got as far as you did.
I've trained people for months and they could not do that....

[Jeffrey Lovely]

also check the calibration sphere size

[Underspec]

Make sure your probe is built correctly within the probe utilities, then calibrate, goto the results and see what the STD (deviation) is. Then re-measure your circle. There are also calculation options for the best fit circle. You should have a help file with PCDMIS which would explain all this I've lost my best fit circle explainations attachment, maybe someone can post it?

[guillaume_martin]

It sounds like it thinks you measured a STUD instead of a HOLE so it will say OUTSIDE instead of INSIDE.

You were right !!!

Thank you very much !!!

Thank you to the others who gave me indications,

Guillaume MARTIN

[Mike N.]

bumps and rep to matt who first noticed that the dev was twice the probe dia

[#2#]

Matt, as your last name almost says you are de-man!