The blade’s journey
The INL-1900x2T has three inspection roles to fill: verify several hundred metrology features of the blade, inspect both sides of the turbine blade and other critical surfaces for defects, and validate the part’s character markings. The entire inspection procedure takes 15 seconds per part.

To perform a batch inspection, an operator first scans the barcode on the job sheet with a scanner and loads the pocket wheel with the carousel that holds the parts. Then the wheel indexes the first part while a height detector validates its y position to ensure the part was properly loaded. Then the robot picks up the part by its blade section and carries it to the metrology station, which is illuminated by the two collimated lights. With the camera’s telecentric lenses, and the four-inch slab of granite to absorb heat and vibrations, the INL-1900x2T enjoys a very stable optical system. “Under these conditions, the contrast of the round sections of really shiny objects appear super sharp,” Dicaire explains.

Precision is extremely important. “The robot is very repeatable, but cannot place the blade with the precision that we need, which is smaller than 10 microns,” he says. Orus’s solution was to rotate the part and acquire the images at high speed. Depending on the feature that needs measuring, the software minimizes or maximizes a specific feature. When an image of a particular reference point, called the datum, matches the original CAD drawing, the software identifies it as the reference image. Then the metrology software measures the part’s parallelism, length, radius, angles and other feature. Since there are many datums to optimize, this step is performed more than once. The software records results for hundreds of features and 50 tolerances.

After the software records the metrology results for all of the blade’s features, the robot places the blade in a three-pronged gripper that is mounted on a Y-Theta station. The clamp rotates the blade 360 degrees to inspect both sides for surface defects. Then the software verifies the part’s character markings: first by stitching together several images to form a complete image and then by passing the OCR algorithms that determine the character.

When the inspections are complete, all the results for the part are logged; all data is retrievable for reporting. If the part passes inspection, the robot puts the part in a good-parts chute. If a feature has failed, the part is held in the clamp and information is displayed on the screen so the operator knows what to correct on that specific part. Then the gripper releases the part into a reject chute. The wheel turns, indexes the next part and the process repeats for all parts in the carousel.