Small-Part Measurement For Quality Control

New Scale Robotics has released a white paper exploring the evolution of Quality Control (QC) measurement techniques for small parts. The paper highlights recent innovations that allow collaborative robots to perform QC measurements, helping to bring the benefits of robotics from the manufacturing floor and into to the QC lab for high-mix, small-batch manufacturers.

Like their counterparts in production, robots in QC automate dull and repetitive work, keep humans safe from injury, and deliver more consistent results.

They further enable automated data collection. Today, 75% of manufacturers—including some of the world’s largest—still collect QC measurement data manually. Of these, 47% still rely on pencil and paper.

By providing better precision and repeatability, and automating data collection, collaborative robots in the QC lab give manufacturers a new competitive advantage in the race to maintain high quality and reduce costs.

The white paper describes:

  • How robotic calipers evolved from manual gages and digital calipers
  • The benefit of smart gages and robotic calipers including electronic data capture
  • Comparative capabilities of machine vision, laser-based scanners, CMMs, robotic calipers, and Q-Span Systems for QC measurement of small parts.

Just as collaborative robots (cobots) brought the benefits of robotic automation to small-batch, high-mix manufacturing, they are now bringing those same benefits to the QC lab.

New Scale Robotics has brought three innovations together and paired them with a Universal Robot cobot to create a dedicated system for automated small-part QC measurement. The Q-Span System can automatically pick parts, measure multiple dimensions on each, and make real-time decisions such as pass/fail based on the results. It can then sort parts into output trays and send all the data to a PC for later analysis.

A typical Q-Span System has one robotic gripper for part handling and one or two robotic calipers to make measurements. In many cases one tool serves as both gripper and caliper. Each caliper is equipped with metrology fingers specific to the part and the dimension to be measured. Dimensions that can be measured include length, width, thickness, outer diameter, and inner diameter.

Because they are small and lightweight, three devices can be mounted on Universal Robot’s smallest cobot. This allows the system to occupy minimal lab space, and perform multiple processes with fewer large moves. The result is high throughput and safety for human operators.

The gripper/caliper replaces a manual digital caliper and has about twice the precision.  When using the appropriate fingertips and established metrology practices, part measurement resolution is 0.0001 inches (2.5 μm). The +/- 3 sigma repeatability and accuracy are factory-certified to be less than +/- 5 μm (0.0002″) and +/- 15 μm (0.0006″) respectively.