Improving the inspection process

An interview with Michael Nahum, Micro Encoder Inc.

Michael Nahum, Ph.D., is president of Micro Encoder Inc., Kirkland, Wash., a wholly owned R&D subsidiary of Mitutoyo Corp., Kawasaki, Japan. MEI develops new technologies and software for products, such as small hand-held measurement instruments like calipers and micrometers, and capital equipment like machine vision systems and coordinate measuring machines. The company employs a combined 85 people at its 30,000-sq.-ft. (2,787-sq.-m) facility in Kirkland and 4,000-sq.-ft. (372-sq.-m) facility near Los Angeles. These facilities include state-of-the-art temperature- and vibration-controlled laboratories, electromagnetic and optical test and measurement equipment, more than 15 machine vision systems and five CMMs. Nahum spoke about the company’s areas of focus, how part miniaturization influences inspection, new metrology devices and techniques that can help part manufacturers meet their needs, and what still needs to be accomplished in order for metrology to improve.

Cutting Tool Engineering: What are the metrology areas that MEI focuses on?

Michael Nahum: We are always looking for new technologies for small hand tools to make them more useful by improving measurement capabilities. Another big focus is research for machine vision systems, where we develop algorithms, software and hardware that provide customers higher throughput, more ease of use, 3D measurement capability and better accuracy. We also develop part program-generation software for CMMs. Finally, we develop technologies for noncontact sensors, such as chromatic confocal systems, and white light interferometers.

Styli as small as 15µm on the UMAP vision system from Mitutoyo enable microscopic-form touch measurement. Image courtesy Mitutoyo.

CTE: Why is metrology becoming more necessary?

Nahum: Precision parts inevitably have to be fabricated to some required tolerance level, and tolerances are growing tighter, especially as parts shrink in size. Better metrology equipment will enable a part to have a slightly looser fabrication tolerance requirement, for example 0.0005 ” instead of 0.0003 “, because less of the cumulative tolerance is consumed by the metrology equipment. This saves our customers money and makes their job easier.

CTE: What’s required to incorporate new metrology technologies into existing measurement methods?

Nahum: First, there must be a key purpose for introducing a new technology, such as better performance or another significant advantage for the customer. Second, customers depend on the results from our products. Therefore, measurement results from the new technology must closely correspond to existing measurement methods. We do not want to make a change that can disrupt a working process. We expend a huge effort checking new technologies to make sure they perform as well as or better than existing technologies under various conditions, including temperature and humidity levels. Third, we want to minimize reengineering to accommodate new technology, which places additional requirements on size, weight and power consumption. All in all, it is a challenging job to develop new technologies for existing methods.