Big Problem on 12-09-2007
We met a big problem that the tip seems wrong and makes some unexpected contact to the sample.
Jerome Rudy and Sheng spent a whole day trying to fix the problem, but faild.
Problem discription:
When doing H-Pattern, it came out with an error about the contact depth exceeded its max 5um.
The curve is very much like an area indent: goes up for a bit than turn down below 0 fast.
Letter to Lance:
Hi Lance,
We got some trouble with the Triboscan today. When doing H-Pattern, it came out with an error about the contact depth exceeded its max 5um. (related curve included in the mail, "H-pattern Cal 0001.hys"). Then we did some tries (logs kept in "log.doc") and narrowed the problem within the Berkovich tip. There was one time(detailed information in log.doc)
when we could finish the indents however the results were uncommon(related curves included in the mail, "problem 12092007.hys" and "problem 12092007 2.hys").
Our analysis: Firstly the problem was narrowed within the tip. Secondly, the reason of this might be the tip detected a certain contact before it really touched the sample. This could be from the mount between the tip and the transducer, like some dirt or crash in the screw in the back of the tip.
Lance's Reply:
Dear Sheng Liu,
From the curves that you sent, it really appears that there is some dirt
or debris on the tip or on the sample. If the tip has been used on a
soft material (like a polymer or biomaterial), it is easy to have
material stick to the indenter tip. This would need to be cleaned off.
I have attached the procedure for cleaning the tip to this email.
Because some of your problems are actually happening on the Aluminum
sample, you could skip the part of the procedure that would have you
make indents in the Aluminum.
If this does not fix the problem, then it may be related to something
loose on the system. I would make sure that the tip is fully tightened
into the transducer. Using the tip mounting tool, you can tighten the
tip until the tool will turn approximately 1/4 turn after the tip has
stopped moving. This will not damage the transducer, and will guarantee
that it is mounted well.
Best Regards,
Lance
