Certification vs Verification in Quality Testing

Don’t overlook this crucial difference.

At Metallurgical Supply Company (METSUCO) we are often asked to provide quotes for hardness testers, calipers, micrometers, and other precision measurement tools to manufacturers and labs.  Sometimes our clients know exactly what equipment or tool they are looking for, down to the specific brand and part number.  But oftentimes, we ask our clients questions to help narrow down the hundreds of choices and help them get the most suitable item at the price point needed.  One of the most critical questions we ask: will you be using the equipment or tool to verify or to certify parts?

This is a crucial conversation, not only for the type of instrument purchased but also for how the lab or manufacturer will present its quality data to its customer. Whether the data is for verifying or certification.

Verifying a measurement, be it hardness, length, mass, or some other characteristic. By verifying you simply check to make sure the measurement is within an acceptable tolerance.  In contrast, certifying a measurement means that some industry accepted quality standard such as ISO, ASTM, NADCAP, or other has been procedurally followed and the part being measured meets the acceptable tolerance as specified in that standard.  Certifying is a much stricter requirement than verifying, but one that could be mandated by the end customer.

Take the case of hardness testers as an example. Almost all acceptable quality standards are written only for benchtop hardness testers.  As such if the purpose of testing is to certify, you should only use benchtop hardness testers. We carry some very nice, very expensive portable hardness testers that are also extremely accurate.  However, if you need to certify the hardness of certain parts, you should use a benchtop hardness tester, not a portable harness tester. When purchasing a hardness tester, you should gauge your customers’ needs and then decide on a portable or benchtop model.

ISO-certified parts manufacturers are required to have certain measurement equipment calibrated and certified annually in order to maintain their overall certification.  This is another consideration when manufacturers are looking at whether they need to just verify some measurement as a quality check or if they need to fully certify that part.  Getting equipment and tools calibrated annually is costly and takes planning. You need to have replacement tools so that you can serve your customers uninterrupted. Some manufacturers will have multiple pieces of critical equipment for this reason, in case one is out for calibration services. In some cases, we have loaner equipment available for clients.

Certifying parts does not always mean that you must buy more expensive equipment and tools.  As with everything, there are trade-offs.  Some benchtop hardness testers that are mechanical instead of digital are very economical.  The level of automation and digitization of equipment drives most of the cost increase.  Some portable ultrasonic hardness testers are very expensive because of the technology, even though they cannot be used to certify parts. On the flip side, high precision calipers that provide accuracy up to 4-decimal places or more will certainly be more expensive than ones that only provide 2-decimal place readings. For many of our clients, 2-decimal places is enough accuracy, especially if the goal is to simply verify (and not certify).

Determining the purpose—verification or certification—can help manufacturers and labs to not only plan for optimizing costs but also get the most utilization from their equipment.

METSUCO has been in business for over 30 years supplying hardness testing, metrology, and other high precision devices.  We are happy to help answer questions and talk through your requirements in order to find the best fit.  We service critical industries such as aerospace, automotive, and oil and gas as well as universities and testing labs.  If there are items you need not found on our site, contact us at 713-827-0700 or sales@metsuco.com. We will custom source the item and provide a quote within 24 hours!