Vision System Provides Traceability for Handpass Assembly System

Cognex Corporation: Innovative Automation was contracted by one of their long-standing customers, a world leader in electromechanical actuators and emission control devices, to design and build an assembly line to produce a new actuator. This unit is a critical engine component; therefore, the client required traceability of the assembly process operations as well as the final testing operations.

Parts are passed by hand from station to station in the assembly system used in this application. The assembly system also includes a four-station dial-machine in which parts are indexed between stations. Innovative Automation utilized a concept of marking a 2D Data Matrix code on the plastic housing of the part that is read at each assembly and test operation.

A Cognex In-Sight® 5110 vision system is used at the first assembly station to verify that the 2D Data Matrix code quality is sufficient to be readable at all subsequent machine stations. Innovative Automation selected the In-Sight 5110 vision system because it provides a vision tool library that makes it easy to program a wide range of industrial applications using a simple point-and-click approach.

At each subsequent assembly station, the code is read by a Cognex DataMan® 100 industrial ID reader, a very economical system that reads 2D Data Matrix codes at high rates of speed. The ID reader sends a signal to the PLC (Programmable Logic Controller) database to indicate that the operation has been completed. Tests are also performed at many stations using vision system sensors, and the results are also added to the PLC database.

If all previous operations have been successfully completed, the part status is considered valid for the station and the assembly or test operation is allowed to proceed. This eliminates the possibility that a rejected part might find its way back onto the machine and inadvertently be shipped to a customer.

The part then returns to assembly station #1 of the machine where the vision system verifies the code and an operator presses a seal, a bearing, and a stud into the lower housing. A second Cognex In-Sight 5110 vision system at the first station looks upward to verify the presence and orientation of a seal and clip in the upper press tooling.

Adam Ritchie, Control Specialist for Innovation Automation, developed the inspection application using Cognex In-Sight Explorer software tools. Ritchie created a box on the image around the seal, and he used In-Sight Explorer’s PatMax® pattern matching feature to train the vision system to look for an image matching the good part.

The part then moves to another station for function testing and returns again to station #1 where the same laser that put on the original 2D Data Matrix code applies another code that includes the serial number and date code for the accepted part.

The assembly system exceeded the customer’s expectations by economically meeting part traceability requirements including tracking part status throughout the assembly process. The customer originally bought a single machine with the vision system, but now insists on a 2D Data Matrix code tracking system on all of its assembly lines.

About Cognex
Cognex Corporation designs, develops, manufactures, and markets machine vision sensors and systems, or devices that can "see." Cognex vision sensors are used in factories around the world to automate the manufacture of a wide range of items and to assure their quality. Cognex is the world's leader in the machine vision industry, having shipped more than 500,000 machine vision systems, representing over $2 billion in cumulative revenue, since the company's founding in 1981. In addition to its corporate headquarters in Natick, Massachusetts, Cognex also has regional offices and distributors located throughout North America, Japan, Europe, Asia, and Latin America. Visit Cognex on-line at http://www.cognex.com.