New advancements in multi-sensor platforms combine the best features of vision and touch-probe gear inspection for maximum accuracy and speed.

Demand for accurate gears delivered on tight schedules is increasing. To keep pace, technology is continually advancing, enabling manufacturers to do more in the same amount of time. Add in competitive global market pressure, and the need for efficiency is more important than ever. To sustain profitability, companies need to keep up with market demands, while maintaining production quality.

One of the main challenges of quality control (QC) is the balance between staying within production tolerance limits and keeping lead times down. Very often, one single gear has many features that need to be kept within tight manufacturing tolerance limits, requiring multiple forms of measurement processes or methods.

Multi-sensor technology, including vision and touch probe capability, may be required in order to fulfill the specific measurement needs. Among these sought-after system requirements, perhaps most importantly, is the need to have fast, reliable data acquisition in the process. The more complex the gear, the higher the demands are for inspection and the more important efficiency becomes. In order to solve today’s challenges, versatile measurement and inspection equipment is now more pivotal in assuring consistent quality.

Multi-sensor measurement systems help solve many of the measurement and inspection challenges that arise in modern manufacturing. (Courtesy: The L.S. Starrett Company)

Multi-Sensor Systems Explained

Multi-sensor measurement systems help solve many of the measurement and inspection challenges that arise in modern manufacturing. Providing exceptional speed and efficiency, a multi-sensor measurement system can easily increase QC throughput by performing multiple processes on a single machine while maintaining accuracy.

For greater efficiency and accuracy, more of the gear can be viewed in every image on the latest multi-sensor vision systems such as the Starrett AVR-FOV 0.14X featuring a 0.14 magnification lens, large field-of-view of 2.36” x 1.90” (60 mm x 48 mm), and automatic part recognition. Due to “super-image” technology, which allows multiple images to be stitched together to form one larger image, together with the system’s touch probe technology, the AVR-FOV 0.14X can accurately inspect a wide range of applications including large, complex, and multiple small gears and parts.

The AVR-FOV 0.14 automated part programs deliver accurate results to the micron level in a matter of seconds with “Go/No-Go” tolerance zones, and data are provided in one easy-to-interpret report. Video-edge detection and touch-probe capability enable measurements to be taken of discreet points along a part’s profile, producing accurate profile and pitch-inspection results across a wide range of gear sizes. Ensuring that gear production is reliable and consistent protects manufacturers from several issues, including excess noise, load and tooth-to-tooth challenges, as well as premature gear wear or failure.

Ensuring that gear production is reliable and consistent protects manufacturers from several issues, including excess noise, load and tooth-to-tooth challenges, as well as premature gear wear or failure. (Courtesy: The L.S. Starrett Company)

User-Friendly Interface is Key

In order to maximize the power of modern measurement technology, however, systems also must be equipped with user interfaces that make the system’s capabilities approachable from a user standpoint. New measurement platforms, such as the Starrett AVR-FOV 0.14X multi-sensor vision system, come equipped with the M3 software package from MetLogix. Systems such as this operate with both a traditional mouse as well as a touchscreen monitor that make user interaction easy and intuitive. One of the top benefits of modern metrology software programs is the speed of throughput due to features such as auto part recognition. A user can create a part measurement program that comprises the desired features of a part for inspection, which can automatically be saved in the system or to a network.

Gear manufacturers can use the line, radius, and circle annotation in MetLogix M3 software to create a part inspection program for an individual gear tooth profile or an entire gear.

Programmable light output options can be built into the program as defined steps, including being called up as the part recognition program initiates. Once the program is created, placing that part within the camera’s field-of-view allows for the saved program to initiate and run the inspection. A Renishaw Touch Probe may also be used for quick acquisition of discreet points along a part’s profile as well as Z-axis measurements. 

These advancements, when combined with CNC control, advanced edge detection, and one-touch measurement, facilitate what is known as “walk-up metrology.” Walk-up metrology enables multiple operators, including those right on the shop floor, to use the same system for a variety of applications. This versatility and ease-of-use significantly helps with bottlenecks in the inspection process and dramatically increases speed-of-workflow efficiency.

New Starrett AVR-FOV 0.14X Multi-Sensor Vision System offers micron level accuracy across a wide range of gear sizes. (Courtesy: The L.S. Starrett Company)


While the many advances in multi-sensor metrology systems are making the inspection process faster and more user friendly, the partnership between system manufacturer and end user has never been more important. Metrology-system manufacturers have a staff of highly trained experts that can help companies determine which systems best suit their needs, such as what lens configurations will serve them best, which lighting and touch probe options will help, and what accessories or custom options might also help them reach their goals. Some system manufacturers also have product specialists in the field who can assist with the best metrology option to be selected, as well as provide post sale support.

Proper installation and calibration of the systems ensure accurate results are obtained. Training company employees is equally important to make sure the many features and programs of the metrology systems are used to their full potential. When technical questions arise and regular service is needed, the system manufacturer can provide guidance about the best methods and techniques to optimize system performance. This may be via phone, online connection, or in person on-site. When a company invests in a multi-sensor metrology system, they are forming a true partnership with the manufacturer that is equally important, if not more so, than the equipment itself. 

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Greg Maisch is an engineering manager with The L.S. Starrett Co. Metrology Division. Starrett optical comparators, vision and multi-sensor metrology systems, laser measurement systems, force measurement and material testing, precision hand tools, gage blocks, hand tools, power tool accessories and saws provide exceptional quality capable of producing dependable and accurate results time and time again. For more information, go to