Starrett.

Gregory Maisch

Quality control and inspection has historically been a costly and time-consuming process for most manufacturers, regardless of their industry of focus. Parts were inspected by hand and marked up as out of specification for further re-work. Only a handful of individuals possessed the training to operate a system like an optical comparator. This system created bottlenecks in lead times and introduced the potential for error between operators.

Furthermore, despite being integral for production, new quality inspection equipment can be seen as financially unrealistic. Ironically, this can end up being an Achilles’ heel for companies that do not stay on the leading edge of inspection technology, resulting in them falling behind their competitors. Fortunately, due to advances in metrology equipment, technology now exists that allows managers to decentralize the inspection process and empower virtually anyone on the shop floor to run inspections while simultaneously obtaining faster and more accurate results, regardless of budget or scope. The following examples illustrate the effectiveness of this technology.

 • Optical edge detection on comparators virtually eliminates the potential for human error by eliminating subjectivity in point data collection.  Traditionally, two different operators may view one part and have slightly different assessments due simply to standing in a different position or looking at the screen from a different angle. Optical edge detection uses fiber optics to automatically detect the transition from light to dark on screen so the same point gets taken every time. Some modern comparators can also be upgraded to use interchangeable industrial cameras for video-based edge detection (VED).

 • Digital comparators are the natural progression of traditional optical systems. Mirrors are replaced by a video camera and powerful software, eliminating the need for physical storage and maintenance of Mylar overlays. VED is standard and CNC can easily be added for extra precision, control and throughput.

 • Vision systems are equipped with powerful software, fueled by VED, which has auto-part recognition and complex profile measurement capabilities. During the initial setup of a system after purchase, the end user’s manufactured parts are set up in the system with the desired features called out. Once entered, a part need only be placed in the field of view and the program will initiate, providing a full report in seconds.

"Due to advances in metrology equipment, technology now exists that allows managers to decentralize the inspection process and empower virtually anyone on the shop floor to run inspections"

 • CAD files can be uploaded to vision systems with tolerance zones to allow for instant comparisons to give “go/no-go” results.

 • SPC software, loaded on the platform for the end user, brings metrology up to industry 4.0 standards. This allows instant feedback on parts in-process, as well the status of the manufacturing equipment. If a machine tool is falling out of spec, it is displayed in easy-to-read dashboards with high visibility color coding. This can be identified and fixed in real time, rather than after large batches of faulty parts have been produced.

These advancements have trickled down from the top tiers of quality control and inspection equipment to become available on virtually any modern system. Much of this new technology can be adapted to existing systems currently used in production as well. While the obvious advantages of these improvements lie in the obtaining of accurate and repeatable results, the less tangible but arguably more important benefit comes from the time saved by making inspection analysis a walk-up process.