With the development of industrial automation, the size of electronic components continues to decrease, making the distribution of solder joints more and more dense. Human eyes are not accurate in detecting solder joints and desoldering conditions. Therefore, high-precision positioning detection methods are required. This solution is VisionBank’s intelligent vision software for high-precision detection and positioning of solder joints.
1. Camera model: MV-EM500M 5 million camera
- Resolution 2592*1944
- Pixel size 2.2μm
- Chip size 1/2.5 inch
- Black and white camera
2. Lens model: BT-118C2520MP5
- Resolution 5 million pixels
- 25mm fixed focus
- Maximum support target surface 1/1.8
3. Ring light source model: MV-RL92X52R-A45-V
- 45 degree luminous area 92*52
- Coaxial light source model: MV-RC50W-V
- Light emitting area 50mm
- Controller: SVC200
- 4G running memory
First, find the position of the hole through feature positioning, and determine the coordinates of the center position of the hole using circle detection feature, to realize the position positioning, and communicate with the other party’s PLC.
Second, through the image preprocessing function, determine the gray value of the image in a specific area. If the gray value is within 30, it can be concluded that the small hole is leaking and the welding is not good. Hence, the PLC alarm signal is given.
Problems encountered in the project and solutions
The main difficulty of this inspection is defect detection. Since the difficulty of the project is that the solder is irregular, the judgement whether it is qualified is based on whether the solder has covered the small hole. Although the ring light source can solve the positioning problem, it cannot accurately distinguish the gray level of the hole and other positions.
By combining the light sources, the coaxial light source on the top and the ring light source on the bottom, it can not only solve the problem of hole positioning, but also show the effect of low gray value of solder joint defects on the image.