For example, New Jersey-based Compex Corp. manufactures single layer components that are used in high frequency radio frequency, microwave, telecommunications and fiber optics products. It produces more than 10 million components annually at its 16,000 square-foot manufacturing facility in West Berlin, N.J. The company felt it had too much labor tied up in manual inspection tasks. Local vision integrator Serview ( http://serview.net) designed a vision system based on products from Natick, Mass., supplier Cognex Corp. (www.cognex.com).
The key to success was the ability to integrate a Cognex In-Sight 1000 vision sensor, an existing Cartesian robot, a vibratory feed bowl and track, an air blow off for part rejection and a programmable logic controller (PLC). One of the main challenges in designing the vision system was configuring lighting and optics so the full range of components could be inspected without making any set-up changes.
The vision sensor first verifies the orientation of the component, and then measures critical dimensions. This involves configuration of finding and measuring tools within the vision system software. Engineers also designed a built-in calibration program allowing operators to easily reset the camera lens magnification within five seconds if the lens goes out of adjustment.
A vision sensor captures and analyzes an image of each component fed from a vibratory feeder bowl. If part orientation is correct, the vision system tells the PLC, which in turn tells the robot to pick and place the part. Total system time is approximately 300 milliseconds. If the component is not correctly oriented, then it is blown back in the feeder bowl by the air blow-off system.
Counting parts
The packaging system involved counting thousands of small components in a short period of time. The existing system required several operators at the station to perform manual counts. Achieving the complete accuracy demanded by customers was difficult in that environment.
The counting system is a tabletop, standalone system that requires no PLC. The integrator chose a single, high-resolution vision sensor capable of 1,600-by-1,200 pixel resolution so that it could find and count the smallest parts the company intends to manufacture.
Proper selection of software “tools” within the vision system is essential for consistent success. First, designers used a tool called morphology that helps the vision system find an individual part in a stream of parts. Then the “blob” tool can reliably define the part for internal counting. Although these are advanced graphic algorithms, users just pick from a menu and configure and teach part definition on the system setup screen.
In operation, an operator selects the part type to be counted using an interface constructed in Microsoft Visual Basic, then turns on the system to view the package in real time on the monitor in order to properly align the package within the camera’s field of view. Once that’s done, the operator tells the system to count. The system proceeds to verify that the parts in the package are correct, and to count them. The image is saved to computer disk and the count data is stored in an SQL database, providing a complete record of all shipments.
Serview Engineering Manager Brian LeBlanc proclaims, “So far, all reports are that the system is 100 percent accurate. We found that up-front testing really paid off, as we have not had to make any changes in the system. The system eliminated a major bottleneck in Compex’s shipping operations and reduced labor costs in the operation by 80 percent.”
Although vision systems are often seen as complex and specialized, planning and integration with existing automation can lead to improved quality and reduced cost for a manufacturer.
