Test & measurement


test and calibrate with confidence


Norbar Torque Tools’ latest innovation, the Torque Wrench Calibrator Auto (TWC Auto), is a wrench loading system that enables testing and calibrations of click, dial and electronic torque wrench designs in accordance with the revised BS EN ISO 6789:2017 standard. As stipulated by the 2017 version of the standard, parasitic forces within the calibration system must now be eliminated. This is where Norbar’s patented counterbalanced reaction is crucial, achieving the required self-alignment and balancing out the weight of the wrench. The rotating transducer design also ensures the load is applied at 90° to the torque wrench handle for unbeaten precision. In addition, the TWC Auto, which is available in two capacities (up to 400.0 N·m and up to 1,500.0 N·m), benefits from data gathering capabilities and an automated process management system. The TWC Auto will calculate the uncertainty figure, which needs to be included within the calibration certificate, and also boasts a calibration job management system for booking calibrations and recording the progress of previous jobs. For enhanced efficiency, the intelligent rate control system provides fast cycling of tools, all while the inbuilt data analysis and certification generation seamlessly moves from calibration/conformance procedures to certificate generation, with no third-party software required.


Norbar Torque Tools www.norbar.com


battery powered usb-based spectrum analyser


Tektronix has expanded its RSA500 family of rugged, battery powered USB- based spectrum analysers with the addition of the RSA513A and RSA518A offering 13 GHz and 18 GHz frequency range respectively. Along with their higher frequency support, these instruments provide the ability to stream I & Q data for customers to perform analysis consistent with software-defined radio functionality. The RSA500 spectrum analyser's small form factor and rugged packaging enable their use for a far wider range of applications. Use cases range from spectrum management applications such as Ku band radar and 5G LTE base station testing to military applications such as like RADHAZ and EMCON monitoring.


With their unique ability to stream I & Q data out of the instrument, RSA500 analysers enable both capture and playback of wideband signals for further analysis offline – a largely unmet need in the market, according to HawkEye 360, a developer of satellite-based precision geoanalytic products.


Tektronix method measures 3d polymer processing precisely


Recipes for three-dimensional (3D) printing, or additive manufacturing, of parts have required as much guesswork as science. Until now. Resins and other materials that react under light


to form polymers, or long chains of molecules, are attractive for 3D printing of parts ranging from architectural models to functioning human organs. But it’s been a mystery what happens to the materials’ mechanical and flow properties during the curing process at the scale of a single voxel. A voxel is a 3D unit of volume, the equivalent of a pixel in a photo. Now, researchers at the National Institute of


Standards and Technology (NIST) have demonstrated a novel light-based atomic force microscopy (AFM) technique - sample-coupled- resonance photorheology (SCRPR) - that measures how and where a material’s properties change in real time at the smallest scales during the curing process. Additive manufacturing is lauded for flexible,


efficient production of complex parts but has the disadvantage of introducing microscopic variations in a material’s properties. Because software renders the parts as thin layers and then reconstructs them in 3D before printing, the physical material’s bulk properties no longer match those of the printed parts. Instead, the performance of fabricated parts depends on printing conditions. NIST’s new method measures how materials


Instrumentation Monthly October 2018


evolve with submicrometer spatial resolution and submillisecond time resolution - thousands of times smaller-scale and faster than bulk measurement techniques. Researchers can use SCRPR to measure changes throughout a cure, collecting critical data for optimising processing of materials ranging from biological gels to stiff resins. The new method combines AFM with


stereolithography, the use of light to pattern photo- reactive materials ranging from hydrogels to reinforced acrylics. A printed voxel may turn out uneven due to variations in light intensity or the diffusion of reactive molecules. AFM can sense rapid, minute changes in surfaces.


In the NIST SCRPR method, the AFM probe is continuously in contact with the sample. The researchers adapted a commercial AFM to use an ultraviolet laser to start the formation of the polymer (“polymerisation”) at or near the point where the AFM probe contacts the sample. The method measures two values at one


location in space during a finite timespan. Specifically, it measures the resonance frequency and quality factor of the AFM probe, tracking changes in these values throughout the polymerisation process. These data can then be analysed with mathematical models to determine material properties such as stiffness and damping. The method was demonstrated with two


materials. One was a polymer film transformed by


light from a rubber into a glass. Researchers found that the curing process and properties depended on exposure power and time and were spatially complex, confirming the need for fast, high- resolution measurements. The second material was a commercial 3D printing resin that changed from liquid into solid form in 12 milliseconds. A rise in resonance frequency seemed to signal polymerisation and increased elasticity of the curing resin. Therefore, researchers used the AFM to make topographic images of a single polymerised voxel. Surprising the researchers, interest in the NIST


technique has extended well beyond the initial 3D printing applications. Companies in the coatings, optics and additive manufacturing fields have reached out, and some are pursuing formal collaborations, NIST researchers say.


NIST www.nist.gov 37 www.tek.com


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