Cognex Vision System Inspects Large Surface Area with High Precision
MEDER, an electronics company located in Shanghai, China, was confronted with the challenge of having to inspect printed circuit boards (PCBs) with a high degree of precision. In order to meet this challenge, MEDER partnered with industrial automation systems specialists at Shanghai Gojoy.
There are many diodes on a welded PCB, and during the inspection process, MEDER required Shanghai Gojoy to inspect every spot weld on the board, whether diode reed switches had moved, as well as PCB electric resistance.
In order to achieve the level of precision required by MEDER, Shanghai Gojoy used a mechanical movement strategy. They deployed an In-Sight® 5403 vision system from Cognex along with three grouped light sources to perform the job. These light sources could be exchanged easily in order to carry out inspections on different objects. Keeping MEDER’s high inspection precision requirements in mind, Shanghai Gojoy carried out design and product experimentation exercises based on MEDER’s data in order to test and perfect the system. From the initial program to the specific final program, Shanghai Gojoy used Yamaha linear drive modules, which were combined to form an XY-direction two-dimensional platform. The platform was installed on a high-precision flat board, so as to ensure mechanical accuracy. The In-Sight 5403 provided the required high mechanical precision image capture throughout the process.
The light source used by the In-Sight 5403 in this setup could be adjusted upwards and downwards. The range of adjustment was not extensive, but sufficient to facilitate installation of the vision system. After the testing was deemed successful, the light was fixed and rendered unable to move in the inspection process.
During the inspection process, the original position of the PCB is defined as zero on the XY movement axis. Based on the location of the diodes on the PCB, the movement along the Y axis is controlled first. After the In-Sight 5403 has reached the desired distance on the Y axis (after the 20th column of the first row has been inspected) the X-axis movement begins, moving to another row on the PCB for inspection. This process continues from the 20th column to the 1st column. The In-Sight 5403 inspects PCB reed switch movement and spot welds and resistance on the board. Each inspection result can be viewed on the display unit. Areas of the board which do not pass the inspection are showed on the display unit in different colors. This facilitates the line operator’s understanding of the inspection process.
This vision system also inspects welded diodes on the board to a high precision, using XY-direction linear module control. Not only does this method guarantee high precision, it also ensures large areas can be inspected. This is a significant technical advance for the machine vision industry.
About Shanghai Gojoy
Shanghai Gojoy was established in March 2000, and specializes in research and development, sales, and technical services for industrial automation systems. The company mainly focuses on industrial control products sales and machine vision promotion and application. This means the company has been continually able to develop machine vision, so in machine vision it is at the leading edge of national technology. In areas such as vision inspection equipment, and special light source design, it has 6 national patents, and cooperates with many international brands. Shanghai Gojoy is considered a preferred partner by Cognex. The Cognex smart camera systems or equipment we use is already widely used by several companies in the industry.