microhardness tester problem

[xara4]

Hi everyone

I have a technical question (perhaps I might say a procedure problem), regarding microhardness testers. I'm working on a Shimadzu HV-2 microhardness tester. The question is:
Does the objective lens play a significant role when I measure the indentation? I have a standard block with 303 HV0.3 measured, according to certification, with a x50 objective lens, while my instrument comes with x40. Does this mean that I can't rely on this standard block to verify if my instrument is calibrated?
I don't know if my question is making any sense. Maybe it is a very stupid question.
Anyway thank you in advanced.

[Gordon]

Hi Xara4

to the Surface Engineering Forum.

Does the objective lens play a significant role when I measure the indentation?

Yes, high quality optics (objectives, eye piece, measuring system of microscope) are required to measure indentations which may be only a few micrometres across.

I have a standard block with 303 HV0.3 measured, according to certification, with a x50 objective lens, while my instrument comes with x40. Does this mean that I can't rely on this standard block to verify if my instrument is calibrated?

No, I don't think so. This is part of the indentation measuring system. The important part is the making of the indentation in the same way as the calibration block is calibrated using same indenter type, force and time etc. To some extent it should not matter about the measuring instrument as long as it is accurate and capable of sub-micrometre measurement. Objective lens is only part of the optics to give magnifications usually around X400 - X500, the eye piece magnification should also be considered (X8 - X12.5 usually).
[quote]

Hope that helps