Solutions

Project:

Engine injector inspection and measurement.

Client:

Machine Vision Systems Integrator

Application:

Inspection and measurement of precision molded parts.

Challenge:

The customer needed to integrate a vision system that could inspect and measure small precision molded parts used in engine injectors (see illustration). One of the critical dimensions that needed to be measured was the width of the ridges. The difficulty was that these ridges are not easily distinguished from the lower areas (A, B, C), which are comprised of the same material and have a similar surface texture. The surface is very smooth, matte with uniform coloration. The customer tried numerous directional and diffuse illumination set-ups with limited success.

Navitar Solution:

The principle characteristic (other than height) that distinguished the lower surfaces from the areas of interest was their orientation. The ridges are horizontal while the lower areas are sloped. This difference could be accentuated by using collimated on-axis illumination in conjunction with a telecentric lens. A 1X Uni-Lite and TC-5028 lens were successful in highlighting the horizontal surfaces and dimming the sloped surfaces, producing enough contrast in the image for measurements to be made. An additional benefit of this illumination is that defects, such as pits on the ridges, are also darkened in the image, allowing them to be detected as well.

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