ASM Online Member Community

 View Only

  • 1.  Metallurgical Microscopes Calibration

    Posted 03-03-2020 11:57
    Hi everybody,
    I'm trying to put together a procedure for microscopes calibration and verification. If we choose to perform the calibration and verification internally by using a certified micrometer, what frequency each of you recommends and if there is any body from an accredited lab or NADCAP certified lab I would like to know what they have in place. 
    Appreciate your help,

    ------------------------------
    Neda Mandkarian
    Metallurgist
    McLAren Engineering
    Livonia
    ------------------------------


  • 2.  RE: Metallurgical Microscopes Calibration

    Posted 03-04-2020 07:57
    If you want to do the calibrations yourself, you will need a certified stage micrometer traceable to NIST.  The steps you have to go through to perform the calibration are complicated and time-consuming for the first time.  When I was in charge of the Matallographic Lab (I'm retired) I did it for several years but when I got audited and written up I decided to hire an outside expert.  Buehler and Leco both are accredited.  ​

    ------------------------------
    [Gene] [Homer] [P.E.]
    [Metallurgical Engineer]
    [Babcock & Wilcox - Retired]
    [Barberton] [OH]
    ------------------------------

    Original Message


  • 3.  RE: Metallurgical Microscopes Calibration

    Posted 03-04-2020 07:58
    I do audits for a 3rd party accreditation body and annually is pretty normal.  Remember that the calibration is camera system scope pair specific.

    It is also common to have some periodic QC check to make sure the the computer system conversion constants have not been changed.

    ------------------------------
    Tom Doggart
    Nomad Metallurgy LLC
    Niantic CT
    ------------------------------

    Original Message


  • 4.  RE: Metallurgical Microscopes Calibration

    Posted 03-04-2020 08:00
    I use an outside source annually.  They are A2LA and for around $1,000 they clean and make any adjustments to both scopes and run the calibrations.

    For that money I can't afford to mess with it.

    ------------------------------
    James Taglieber
    Lab Manager
    Miami Valley Steel Service
    Piqua OH
    (937) 773-7127
    ------------------------------

    Original Message


  • 5.  RE: Metallurgical Microscopes Calibration

    Posted 03-04-2020 10:07
    ​As stated by others, you'll need a stage micrometer that is calibrated with traceability to NIST. You should also review ASTM E1951 and write your own in-house procedure based on ASTM E1951. We are A2LA accredited for testing and we calibrate our own microscope, so we have to comply with the uncertainty reporting requirements as well, which can take some work to get in place if you haven't done that before. If it's not required to be accredited to ISO 17025, then you could skip the uncertainty reporting aspect.

    I'd recommend adding some preventive maintenance aspects to your procedure as well, since most audits look at PM records when auditing calibration records of microscopes.

    ------------------------------
    Paul Elliott
    Arconic
    Eureka MO
    ------------------------------

    Original Message