Calibration Sphere

[tenndoc]

have also found that cmm experts are like golfers they all have a differnt swing so to speak.

All have a different swing - I like that - and it is very true. So, to follow that analogy, just keep hacking away and checking this forum. When you end up in the rough, and you will, log on and ask your question.

Its all good!

[baylorbear]

SPHERE CALIBRATION

Thanks for the information. We are very careful when we use the calibration sphere because they are not cheap. I had to answer for when the last one was broken. I have found alot of useful information on this forum. I started working with PCDMIS and CMM work about three years ago now. We have came along way in three years but haven't really scratch the surface with its capabilities. I learn something new everday but I do not have any background prior to starting this job. It is very difficult to figure things out when you do not know all of its capabilities. I have also found that cmm experts are like golfers they all have a differnt swing so to speak.

[Don Henger]

sphere

Its every three years for us. I don't recall who calibrates it. (different dept.) We had one that came with a Merlin and some one had glued the sphere back onto the holder. We took it off and just had it sitting on the top of the holder and had a newby do a tip qual. You should have seen his face when it fell off the holder

[Jan d.]

We calibrate our spheres yearly. However, it is important that you check for dents far more regularly. We have a 2nd and 3rd shift and therefore communal cal spheres. Not everybody will fess up that they bumped it... So keep a sharp eye out for your sphericity. I even went as far as to plot it daily. Found that it is very close (the same number) for a "standard" (one you use a lot) set of tips. Even if you have a few tenths variation, start to rotate the sphere first. If it gets better, you may have a bumped sphere. If not, you may have something in your probe system...

It never ceases to amaze me how "repeatable" call sphere sphericity is for the same tip. Doesn't mean it is perfect, but I seem to get always very repeatable numbers.



Jan.

[Doug Wells]

We have our calibration artifact verified every 5 years. I believe we send it to Fox Valley Metrology in Wisconsin.

Hope this helps,

Doug Wells

[baylorbear]

How often do you have your calibration sphere certified? If yearly, Do you know who can certify it for me? I can't ask my support because a year ago they dropped one and tried to glue it back together. That is how important they thought it was. I have a new one now and we usually certify things yearly. I haven't been able or had time to check into it lately. This is my first post so go easy.