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VisionGauge® Bone Screw Inspection & Measurement Module Provides Medical Manufacturers with Crucial Benefits

The VisionGauge® Digital Optical Comparator offers new technology for drastic inspection advancements and overall cost reduction for medical bone screw manufacturers, including a dedicated dual-rotary module specifically designed for bone screw inspection as well as a patented Tooth Checker™ tool for completely operator-independent thread inspection. These advances represent a huge improvement over traditional optical comparators and overlay charts.


Medical bone screws are widely used fixation devices in orthopedic reparative and reconstructive procedures. There is a very wide range of orthopedic screws made of different materials with various coatings. By design, bone screws require hard-to-machine materials, which makes producing their complex threads difficult.

The importance of complete and proper inspection & measurement of bone screws throughout the manufacturing process cannot be overstated. It’s key to allow medical manufacturers to ensure correct performance, conformance to specifications and reduced variability of the final product.

The VisionGauge® Digital Optical Comparator now offers a new enhanced dedicated complete dual-rotary assembly, designed specifically for the fully automated inspection & measurement of bone screws. It allows the full rotation of the screw (to check run-out, for example), its orientation at the helix angle, etc… This module also includes dedicated workholding (either pneumatic or manual) compatible with bone screws that have a thru hole as well as those without. When fitted with a pneumatic chuck, this dedicated dual-rotary assembly allows VisionGauge® to be used in a fully automated bone screw manufacturing cell, with robot loading & unloading, for complete “lights out” operation.

The VisionGauge® Digital Optical Comparator is widely used by medical device manufacturers for automated inspection and measurement of bone screws. VisionGauge® presents many unique benefits for this application, including the following:

  • It can automatically compare bone screws against their CAD data
  • With its proprietary patented CAD Auto-Align™ and CAD Auto-Pass/Fail™ tools, the system can check screws completely automatically, regardless of their orientation!
  • With its patented Tooth Checker™ tool, VisionGauge® is able to check the thread profile automatically, to ensure that all of the thread’s peaks and valleys fall within their tolerance band, regardless of the screw’s clocking
  • Completely eliminates operator subjectivity!
  • Collect measurements, statistics, images, and other data for complete device history, completely automatically
  • Thanks to the system’s extended depth-of-field, the entire screw can be in focus even at the helix angle (no need to constantly refocus)!
  • Measure the screw’s major and minor diameters, tooth pitch & spacing and other characteristics – even runout – completely automatically and to a very high accuracy
  • With the optional rotary stage, you can automatically measure the helix angle, very accurately!
  • The system is perfect for inspecting & measuring bone screws directly on the shop floor

With its wide range of measurement tools and great flexibility, VisionGauge® has no problem inspecting & measuring 100% of the features on bone screws, including the head, the thread and the tip. Furthermore, VisionGauge® works very well all of the different types of bone screws and all bone screw materials and finishes.

VisionGauge® also has a patented Tooth Checker™ tool that is a key feature that makes this system ideal for inspecting bone screw threads. This easy-to-use tool imposes absolutely no limit on the part’s geometry and can ensure, almost instantly and regardless of the screw’s clocking, that all the threads’ peaks and valleys fall within the specification tolerance band. This is a powerful and unique tool that represents a huge advance in bone screw inspection. For medical bone screw manufacturers, ensuring a proper thread profile is key as many of the screw’s properties (such as its pull-out strength) depend on a proper thread profile. VisionGauge®’s patented Tooth Checker™ tool is completely operator-independent and represents a huge improvement over the combination of traditional optical comparators and overlay charts that manufacturers have used historically to control screw threads.

VisionGauge® can also measure all the screw’s features and critical dimensions, such as:

  • Major diameter
  • Minor diameter
  • Pitch diameter
  • Thread pitch
  • Helix angle
  • Lead and trailing flank angles
  • Root radii
  • Taper
  • Lead
  • Circularity
  • Etc…

The importance of proper inspection of bone screws, both during the manufacturing process and at final inspection, cannot be overstated. Proper inspection allows bone screw manufacturers to ensure correct performance, conformance to specifications and reduced variability of the final product. Furthermore, real-time inspection & measurement with VisionGauge® allows medical manufacturers to optimize the manufacturing process, reduce overall manufacturing costs, improve process control and enable process & part improvement. VisionGauge®’s statistics, data collection & exchange and reporting provide manufacturers with product traceability and device history.

The VisionGauge® Digital Optical Comparator is the new standard for measuring and controlling the geometry of medical bone screws. It allows orthopedic screw manufacturers to ensure that their products have good surface finish and dimensional accuracy. It reduces inspection time as well as overall inspection cost. It eliminates operator-to-operator variation altogether and enables manufacturers to collect accurate numerical values of screw dimensions automatically, to compute process statistics and create complete inspection & measurement reports, making it a highly valuable tool for process control and improvement. The VisionGauge® Digital Optical Comparator allows medical bone screw manufacturers to gain a real advantage in today’s competitive medical products market.

To learn more about the benefits of the VisionGauge® Digital Optical Comparator for bone screw inspection, please contact us, either by visiting our web site at or by emailing us at

Josh Sandberg

Josh Sandberg is the President and CEO of Ortho Spine Partners and sits on several company and industry related Boards. He also is the Creator and Editor of OrthoSpineNews.

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