The difference between CMM Verification and CMM Calibration

Do you know the difference between calibration and verification of measuring equipment?

If you’re unsure, you’re not alone! These terms are often used interchangeably, which can create confusion. At Status, we get asked about this all the time, so we’re here to clear things up for you and explain exactly what’s involved in each process.

What Is CMM Verification?

Verification, also known as certification, is the process of confirming whether or not a CMM is performing within its stated specifications. The probability that think of verification, or certification, as a way to double-check that your Coordinate Measuring Machine (CMM) is performing to an expected and acceptable level. It’s a tick box to make sure it’s operating within its stated specs form the manufacturer.

During verification, you can set the maximum permissible error, the largest error you’re okay with. But keep in mind, verification doesn’t tweak your machine to improve accuracy or make corrections and that’s where calibration comes in.

What Is CMM Calibration?

Calibration is all about bringing your CMM back to its original, top-notch performance. This service is entirely separate from verification and involves measuring a verified artefact and comparing the details of the measurement to the artefacts established dimensions. From this comparison, small precise adjustments can be made to ensure your machine is as accurate as it was when it first left the factory. When considering calibration, there are a few important things to keep in mind.

Key Things to Consider

1. Accuracy is everything in metrology, so you’ll want to be cautious about widening your tolerance for permissible errors during verification as it can impact measurement quality. It’s also crucial to know exactly what your CMM service provider is offering. Some might use the term ‘calibration’ when they really mean ‘verification,’ which can sound more impressive than it is, especially if they’re not adjusting your CMM’s error map.
2. Make sure you know what kind of service you’re getting. Will your CMM receive a full tune-up to bring it back to OEM specs as part of regular maintenance? Or will you just get a certificate confirming the permissible error or whether your machine’s performance has drifted?
3. Another thing to keep in mind is how long the process will take. At Status, we always recommend a two-day visit. Here’s why: our Length Bars (Gauge Blocks) need at least 24 hours to acclimatise to your machine’s environment. So, when our engineers arrive, the first thing they do is unpack the gauge block to kick off this soaking process, while they handle other service tasks.
4. Finally, the most important thing to check is your service provider’s certification. Are they an accredited calibration laboratory under UKAS? Do they certify equipment to the UKAS standard? These accreditations are essential for ensuring your provider is up to the task, whether they’re performing a full calibration or just a verification.

What is Pre-Calibration?

Pre-calibration is a smart step to make sure your CMM is ready for calibration without any hiccups. It’s a great way to save time and money! Our Status Service Engineers follow a thorough checklist to ensure everything is in tip-top shape before calibration. This includes checking cables, connections, and the air filtration system, running a measurement cycle, wiping down the machine and computer, reviewing firmware levels, and more.

Ready to Take a Closer Look at Your CMM Calibration and Verification?

We’re here to help! At Status, our team of calibration and maintenance specialists focuses solely on Coordinate Measuring Machines. With nearly 40 years of experience and UKAS accreditation, you can relax knowing that your CMM is in expert hands.

Let’s keep your CMM running at its best!

Speak to one of our experts now on 0115 939 2228, or contact us here.