XRF is a non-destructive analytical technique used to determine the elemental composition of materials. This technology is used in mining and exploration, positive material identification for power generation, metal manufacturing, inspection, and recycling, precious metal and jewelry analysis, consumer safety and regulatory, and other industries.
XRF analyzers determine the chemistry of a sample by measuring the fluorescent (or secondary) x-ray emitted from a sample when it is excited by a primary x-ray source. Each of the elements present in a sample produces a set of characteristic fluorescent x-rays (“a fingerprint”) that is unique for that specific element, which is why XRF spectroscopy is an excellent technology for qualitative and quantitative analysis of material composition.
But the instrument must be precisely calibrated in order to ensure the results are accurate. Calibration is the process where you confirm that your measurements are true by measuring against a standard. Calibration is usually done on the instrument before it gets shipped out the manufacturer’s door. And although portable XRF analyzers are usually quite rugged, especially since they are sometimes used in harsh environments, equipment degrades over time and should be recalibrated periodically.
It makes sense then, to check, adjust, or determine by comparison with a standard the accuracy of your instrument on an ongoing basis. It is recommended that you follow the manufacturer’s recommendations for recalibration as well as consider the operating environment, the extent of use, and the history of the instrument. Companies might even have to comply with a calibration schedule to ensure compliance with an ISO Quality Document. For instance, ISO/IEC 17025:2005 specifies “the general requirements for the competence to carry out tests and/or calibrations, including sampling. It covers testing and calibration performed using standard methods, non-standard methods, and laboratory-developed methods.”
Generally, recalibrations should be done annually to ensure that measurements are accurate within the specification limits that led you to select the instrument in the first place.
However, recalibrations should only be done by the manufacturer’s qualified technicians. Never attempt to open up the instrument as you can damage or compromise the technology, and could void the warranty. The manufacturer can also supply a calibration certificate to assure customers you are accurately verifying your materials.
In addition to calibrating the instrument, the manufacturer should also offer hardware checks and maintenance inspections to ensure everything is working to factory specifications. Trained technicians should examine the housing to make sure there are no cracks or damage, make sure the touch screen is functional, and test all port connections. Additionally, the LCD lighting should be checked for brightness, the trigger, navigation, and shutter buttons should operate normally, the camera (if the instrument comes with one) should be in focus, and the battery should be tested to ensure it takes a charge.
Are you tempted to skip the calibration and maintenance because you cannot run your business without your XRF analyzer — and you just keep putting it off? Don’t. There are too many negative consequences that could occur if measurements are not within tolerance. If your analyzer is not operating at peak performance you could be risking inaccurate measurements and bad components getting into your shop and through to the customer. Expenses could increase because you need to rework products or delay shipments. Returns from the customer could skyrocket. All of these scenarios could result in unhappy customers which hurts your business and your brand.
Ask your manufacturer if they offer an annual calibration and certification program and a calibration guarantee so the analyzer continues to be under a limited warranty throughout the year. Some companies may even have rental units to help you keep your business running without missing an XRF analysis beat.
Calibration and maintenance is all about confidence in the measurement results you’re getting and addressing any issues before they become urgent matters. It’s really about peace of mind.
By Paul Pazareskis on February 2, 2016