EPIC engineered a 360-degree vision inspection system that ensures 0% false positives and minimizes false failures while inspecting automotive canisters at speeds of 1,200 parts-per-minute (PPM). One of the greatest engineering challenges of this project was eliminating the glare created by direct and stray reflections of light inside the small canister.
Client: Fortune 500 Automotive Products Company
Industry: Automotive Industry
KEY ENGINEERING FEATURES:
- System capable of inspecting parts at speeds of 1,200 PPM
- Three In-Sight vision inspection systems with a fiber-optic light source
- Unique polarization filter setup to eliminate glare
- Inspecting canisters at 360-degrees at speeds of 900 PPM
- Overcoming glare
- Achieving 0% false positives
- Minimizing the percentage of false failures
When manufacturing metal canisters for the automotive industry, EPIC’s client applied a bead of sealant to the interior of a cylindrical piece of metal so other parts could be attached. At a production rate of 900 PPM, manually inspecting for the presence and uniformity of this sealant was both time consuming and labor intensive for the customer.
EPIC reduced the number of falsely failed parts by developing a vision inspection system that could detect the presence and position of the sealant bead while measuring its width around the circumference of the 10mm diameter canister. This was accomplished by arranging three vision inspection cameras such that each camera captured a 120-degree segment of the interior surface of the canisters as they moved along a conveyor.
Adjusting for glare, while a common part of EPIC’s engineering process, was particularly challenging in this case. In many applications, glare can be eliminated by correctly positioning lighting and cameras, but in this case, there was not enough room to accomplish this. To overcome this glare, a machine vision system was developed that employs polarizing filters. Furthermore, while glare can usually be reduced by using a single filter, the cylindrical geometry of the object under inspection interfered with the ability to use a simple 1D polarizer for a multiple camera system. For this reason, the glare in this application was reduced by using a setup three pie-shaped of polarizing filters.
Each pie-shaped polarizer angle serves to geometrically reduce the reflected light from low-incident angles, for a specific camera. The system reduced direct reflections of light by being cross-polarized by a polarizer filter mounted on the camera lens. This allowed a single light source to be used while optimally polarizing that light source for each individual camera.
Automating this process allowed EPIC’s client to inspect parts more efficiently and gave them more confidence in the pass/fail rates reported during inspections. EPIC’s solution saved the client time and labor costs.
EPIC’s vision inspection system kept false failures to less than 300 parts per million.