Inspec Insights

Is Your Equipment REALLY Measuring Accurately?

Interim check, verification, and or calibration allows you to track your measurement equipment accuracy, and know whether it’s in or out of specification.  The problem is, if it is out of specification, when did it go out and or is the equipment accuracy drifting.  For the perfect quality system and maintaining perfect manufactured parts, your measurement equipment would have to always hold accuracy and be within its calibration specification.

Let’s say you calibrate your CMM or vision system at a frequency of once a year.  You receive a nicely assembled ISO-17025 calibration certificate that shows the measuring equipment has been adjusted and the “After” results are within OEM specification - GREAT.  You also find that the “Before” data was Out of specification.   The question is when, or more importantly how much Out of specification and how does this affect the parts you measure between calibration?  

So the bigger concern now becomes, you may have produced a bad product or part and not even know it.  That’s where the interim checks may be as important as each year’s accredited calibration. 

Interim check procedures and process are a quick, low cost effective way to maintain all your precision equipment’s accuracy and support good measurement results.  Increased interim checks should be taken into consideration for those who are working to maintain extremely tight tolerances closer to the equipment specification.  Change in equipment’s calibration frequency can be determined by each piece of equipment’s interim check timing, calibration or certification data history, thus insuring equipment’s measuring reliability.  It’s the between interim checks can be just as important as a calibration.

Return your attention back to the vision system example that was previously discussed.  It’s calibration frequency, once per year.  You have your Vision calibrated and it’s “After” data is within specifications.  Since you already have an interim check process (if you don’t, we highly recommend creating one to keep manufacturing cost to a minimum), immediately after your calibration, you complete an interim check and record & save the data.  This interim check and calibration data now provides you a baseline for the vision system and the start of your data history.  

At this point you need to determine how often to continue with Interim checks.  Where you do not use the measuring equipment very often you may want to perform an interim check just before you measure a part and compare it to the data saved following your calibration.  If your equipment is used more frequently, daily or weekly, the interim check may be performed at the same intervals, respectively.  As always, record and track the interim check data.

The data you have been collecting may allow you to increase or decrease your calibration or frequency.  The data will also create a balance of the calibration and interim checking system process that supports increased quality and reduce overall manufacturing costs to the organization.  To discuss setting up an interim check process or acquiring an artifact contact us via phone or email, we’d love talk with you.

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