Explore the cutting-edge technology in non-contact thickness measurement that utilizes low-coherence interferometry to detect and quantify micron-level errors in robotic movements, enhancing accuracy in industrial applications.
Collaborative robots have long been invaluable in production settings, automating tasks that require precision and consistency. However, their integration into metrology—the science of measurement—has opened new avenues for their application. Equipped with non-contact measurement probes, collaborative robots can execute complex measurement configurations that were previously unattainable.
For instance, a collaborative robot can scan both the anterior and posterior sides of a sample without the need for re-mounting, thereby improving efficiency and reducing potential errors. This versatility makes robotic arms an essential tool in modern metrology, where precision and accuracy are paramount.
Low-coherence interferometry (LCI) is a powerful optical technique used for non-contact thickness measurement. It works by splitting a light beam into two paths: one that reflects off the sample and another that travels a reference path. When these two beams are recombined, they produce an interference pattern that can be analyzed to determine the thickness of the sample with high precision.
LCI is particularly advantageous in applications where contact-based measurement methods could damage the sample or introduce additional errors. By incorporating LCI into robotic metrology systems, engineers can achieve highly accurate measurements while maintaining the integrity of the samples being examined.
While collaborative robots offer numerous benefits in metrology, they also introduce unique challenges, particularly related to movement accuracy. Unlike production tasks, metrology applications require extremely precise positioning to ensure accurate measurement results.
To address these challenges, it is essential to map the robotic movements carefully. This involves comparing the programmed movements of the robot to a known precision surface and quantifying any deviations. By doing so, engineers can identify and compensate for movement errors, thus improving the overall accuracy of the measurement system.
In a recent study, Lumetrics scientist, David Compertore, and the engineering team at Lumetrics, used a 6-axis collaborative robot with a 946 mm reach to quantify movement errors using low-coherence interferometry. The LCI probe was mounted on the robot, and various movement paths were programmed, ranging from linear to smooth arcs at different reach locations.
By measuring the airgap between the LCI probe and a precision optical flat, Compertore and his engineering team were able to detect deviations from the ideal motion paths. These deviations ranged from sub-micron to micron levels, highlighting the importance of precise movement mapping in achieving accurate metrology results.
The ability to quantify and correct for robotic movement errors has significant implications for industrial applications. Improved measurement accuracy can lead to better quality control, reduced waste, and increased efficiency in production processes.
Moreover, the integration of advanced technologies like low-coherence interferometry into robotic metrology systems enables manufacturers to perform more complex measurements, driving innovation and competitiveness in various industries. As the technology continues to evolve, its impact on industrial applications will likely expand, offering new opportunities for precision measurement and quality assurance.
For more information on custom measurement fixtures with collaborative robots, please email sales@lumetrics.com