Dimensional measurement equipment calibration checklist

Of all the variables that can be measured with test equipment, units of dimension are among the most fundamental of all. The ability to verify how large, small, round, square, smooth or flat something is will play a part in every manufacturing process. As a result, maintaining precision in dimensional measurement is key to ensuring that your production or engineering activities consistently achieve the highest quality levels.

As the accuracy of your dimensional measurement equipment relies on expert calibration, so too does your ability to deliver a professional service. Equipment out of calibration risks critical dimensions not being measured accurately enough for you to guarantee the highest standards.

What is dimensional measurement equipment?

Any apparatus that delivers a reading based on a size or distance can be categorised as dimensional measurement equipment. A Surface Roughness Tester checks for grooves or imperfections of a few microns, while a Laser Measure will gauge distances of hundreds of metres.

Between these two extremes there is a wide variety of devices, both analogue and digital, to meet every measurement requirement:

• One of the most common pieces of dimensional measurement equipment, the Micrometer is as old as industry itself. Robust and simple to use, they’re used widely to measure length by expressing the distance set between their measuring faces. A brake disc, for example, can be checked if it is still within its wear limits using a micrometer.
• For dynamic measurements, a Dial Test Indicator (DTI) can be used. A plunger or lever is set against a surface, and deflection measured throughout its range of motion is displayed on a dial. This can be analogue or digital. Alignment of machine tools or equipment couplings may use a DTI to check for any surface run-out.
• Ultrasonic Gauges can measure thickness by measuring the time it takes for a sound pulse to travel through a material and be reflected back. This is useful in Non-Destructive Testing applications, such as testing if steel pipes have been compromised by internal corrosion.

As with any test equipment, accuracy of the readings will inevitably drift with time and use. Mechanical damage to measuring faces, wear of the calibrated adjustment screw or contamination of the ultrasonic transducer will impact on the repeatability of such instruments. Left unchecked, your equipment will soon generate readings that are sufficiently inaccurate to have potentially serious consequences.

Regardless of what is being measured and how, all your dimensional measurement equipment needs periodic calibration to protect the integrity of your business.

How often should dimensional test equipment be calibrated?

Every item of calibrated test equipment has a calibration interval recommended by its manufacturer. However, it is not necessary to adhere rigidly to this. In practice, there are several factors that can dictate if calibration is required more or less frequently.

The environment in which the equipment is used, the skill level of the operator and the manner in which the device is stored between tasks can all play a major role in accelerating the onset of measurement drift. Overloading a tool, use in a hostile environment (hot, cold, humid, or corrosive) or using it in a manner for which it was not designed can introduce inaccuracy into the device. This requires more frequent calibration checks to maintain the correct function of the machine.

While going through a calibration process too often will never damage the device, it can become a costly process, especially when equipment down-time is factored into the equation.

The solution to maintaining accurate readings while maximising availability of your machine is to engage with an experienced calibration partner. They will have first-hand experience of your equipment type and the actual periods over which it is known to drift. They can then factor in the circumstances of use to devise an optimised, cost-effective calibration strategy.

Trust an expert with your dimensional measurement equipment

The technicians entrusted with calibrating your test equipment at DM System & Test are trained specialists. They have extensive experience with dimensional measurement equipment used in such precision industries as defence and aerospace.

Such is our commitment to excellence, we offer accredited calibration services with an ISO 9001 quality management system. Our accredited services extend to on-site calibration carried out at your location, as well as work carried out in our calibration laboratories.

For more information on calibration strategies, on-site calibration or to find out more regarding our dimensional measurement calibration services, contact DM Systems & Test.