EPIC’s Machine Vision article is featured on the cover in the May 2014 edition of Vision Systems Design magazine. Machine Vision Systems professional, Chris Walker is featured in the article explaining the industrial vision system that EPIC developed to reduce the number of false failures in an automated inspection system for sealant on automotive canisters.
The client needed an industrial vision system to inspect the canisters for presence and uniformity to determine the sealants position and consistency.
On a production line that moves 900 parts/min, manually inspecting each canister is time consuming and labor intensive. Therefore, the client was in great need to automate their system, as well as to achieve a false failure rate of 0%.
We combined three In-Sight vision systems from Cognex with a fiber optic light source to allow the cameras to work together to capture 360 degrees of the interior surface on the canisters as they move down the line.
To achieve our false failure rate of 0%, we introduced two methods of vision inspection. In order for each canister to be indicated as “good,” it had to clear both inspection methods.
For the first inspection method, we used edge tools from Cognex Vision Tools software. This software was used to locate the top and bottom edge of the sealant as well as the top edge of the canister. With this we were able to measure the distance of the sealant bead from the top edge of the canister.
We used histogram tools as our second inspection method. Histogram tools counts the number of pixels meeting certain requirements within a specific area. This allows the bead to be located and inspected for any flaws such as breaks or holes in the sealant.
Along with these two inspection methods, we introduced a way to reduce the glare. If glare is not reduced or eliminated, it can cause key features to be missed during the inspection process. To overcome this obstacle, we added polarizing filters on the camera lens, and we placed three pie-shaped polarizers into a fiber optic end effector.
By using optical polarizers and filters we were able to simplify the machine vision algorithm. The algorithm has been tested on both the Cognex In-Sight Micro 1400 and High Speed In-Sight 5600 vision system. The In-Sight 5600 enables a production speed of 1200 parts/min.
Interested in integrating an industrial vision system to inspect parts or products on your production line? Click here to contact Dan Nadolny, EPIC’s Vision Group Coordinator…