Industrial metrology is a central component of high-reliability quality assurance and control (QA/QC). It plays an end-to-end role in manufacturing, where metrological instruments are used prior to part production for machine calibration and in post-production for verification. However, modern production methods and techniques increasingly push the frontier in terms of new manufacturing capabilities, which puts a strain on standard metrological systems like coordinate measuring machines (CMMs).
3D metrology is widely envisaged as a solution to these limitations, while presenting new opportunities for metrological accuracy in industrial QA/QC.
Part of the attraction to 3D metrology is based on the extremely smooth motion control used. This article will explore the basics of 3D metrology and the benefits of frameless, slotless motors for extremely smooth and accurate motion capabilities.
What is 3D Metrology?
3D metrology is scanning technologies that exceed the performance characteristics of standard CMMs. Traditional metrological instruments use contacting probes to acquire dimensional information from test parts along X-Y-Z axes, yielding a series of coordinates that are compared to established data. Contact-based 3D measurement solutions are still used, but non-contacting 3D metrology solutions based on optical technologies (lasers, structured lights, photogrammetry, etc.) are preferred for their speed, resolution, and accuracy.
Challenges in 3D Metrology
Optical 3D metrological surface inspection enables users to create a fully three-dimensional representation of the test part which is subsequently rendered as a 3D color map with clear visual indications as to whether components are out of specification. Individual problem areas that fail to meet tolerances can be easily identified, streamlining defect inspection and general QC applications. The challenge therein is ensuring that machine capabilities align with those of the optics.
Without precise motion control, it is impossible to guarantee accurate readings which may lead to increased defect rates, higher volumes of rejected materials, component failure, and product recalls.
Frameless Motors for Metrology
Frameless motors that are slotless are an ideal solution for the challenges posed by stringent positioning requirements in 3D metrology. Unlike slotted motors, slotless motors have stators whose copper coils are wound and potted in epoxy rather than being wound around iron teeth. By removing the ferrous material in the stator, cogging torque is eliminated. Cogging torque is torque ripple that is caused by the slots in a slotted motor. As the rotor spins, the inherent attraction between the iron teeth is reduced at every slot, causing inconsistent torque. This effect is most noticeable at low speeds in slotted motors. The very smooth motion and direct-drive principles offered by frameless slotless motors make them ideal candidates for metrology applications. High quality imaging is enabled and scanning data is able to be collected from the accurate, smooth motion delivered.
Interested in slotless motors? Learn more about the Agility™ Series direct drive frameless slotless motors.
3D Metrology Component Solutions from Celera Motion
At Celera Motion, we have developed a series of zero-cogging direct-drive motors that are ideal for 3D metrology applications. Our AgilityTM series of zero-cogging direct drive motors is based on the slotless motor technology described above, and offers exceedingly smooth velocity control and low vibration.
Are you looking for frameless motors for 3D metrology applications? Contact a member of the Celera Motion team today for full specifications on our AgilityTM series motors.