Trends are not typically something that come to mind when we think about metrology; however, there have been some recent shifts in the industry worth taking note. Although these moves happen slowly over time when they do occur, we are starting to see some significant changes unfold.
First, we are shifting more toward international standards for force and torque calibration. Testing machines that apply and indicate force are used in many industries various ways. For example, they may be used in a research laboratory to measure material properties or in a production line to qualify a product for shipment. No matter what the end use of the machine may be, it is necessary for users to know the amount of force that is applied, and that the accuracy of the force value is traceable to the standard.
International standards also have several advantages that national standards lack. By using international standards, metrology professionals can perform a wide range of tests using the same machines and calibration standards. This saves time and also impacts the results companies can report to their customers. Rather than converting results to each country’s standards, international standards help streamline the process.
Artifacts Are Long Gone
Additionally, there has been a recent move away from using artifacts as measurement standards. After more than a decade of proposing and planning, the last artifact that defined the kilogram went away in May 2019. The kilogram has been historically based on a physical chunk of platinum-iridium that resides in a lab. However, basing measurement standards on a physical object is bound to cause problems. The iridium can chip and erode, which then changes the definition of the kilogram. Because of this, the kilogram is now based on Planck’s Constant.
Lower Uncertainty Levels
Out of the trends shaping metrology today, driving lower uncertainty levels has been the most prolific. In a wide range of industrial applications ranging from materials testing to industrial weighing, there is an uncertainty requirement on the force measurement. The equipment used to make the measurement must be traceable to a realization of the SI units of force.
When someone is calibrating a device, it is critical that the forces applied be accurate, and the measurements need to be stabilized quickly and easily. It’s becoming increasingly common for Interface customers to request measurements with lower uncertainty at lower forces more than ever, and metrology professionals need to adapt to this change. The end users who benefit most from this trend are those who manufacture or utilize testing machines. With a testing machine, professionals do not need to use new machines and calibration standards for everything. An object that is 75 pounds and another that’s 15 pounds can now be tested by the same machine.
The trend toward reducing uncertainty also pushes professionals to evaluate their contributors to uncertainty by reducing its highest contributor. While reproducibility largely tends to be the highest uncertainty contributor, other factors like electronic noise and temperature and how test machines are run can influence uncertainty as well. For example, if force is being calibrated with a deadweight system, the concern would be reproducibility with electronics. Whereas using a different technique such as hydraulic equipment would bring up different concerns.
There are a few bits of actionable advice that come from these trends. First, all metrology professionals should work to understand all causes of uncertainty. Is it reproducible, or is another factor skewing the measurements? Second, determine where and how you can reduce uncertainty. Lastly, choose a market to specialize in and make sure you have the proper equipment with the proper ranges.
Although trends in metrology are not quick to occur, metrology experts should stay on top of how the industry evolves over time. These trends in particular are working to push the industry forward by improving the reliability and standardization of measurements, and metrology professionals need to take notice.
For more information: www.interfaceforce.com
This article was authored by Ken Vining, Chief Engineer, Interface