AEi developed an automated manufacturing system to laser weld wire shapes into stents for a worldwide manufacturer of medical devices for cardiovascular surgery. These systems were deployed at multiple manufacturing sites both in the US and Europe.
Platforms & Products:
- Vision Guided Laser Tool (VGLase)
Processes & Tools:
- Precision Motion
- Machine Vision Guided Automation
- Laser Processing
- Vision guided motion
- Multi-axis motion for helical weld trajectories
- YAG laser welding
- Laser safety interlocks
Stents are medical devices inserted into arteries to keep the artery open for free blood flow. They are essentially cylindrical wire meshes or structures and have different mesh patterns, sizes and shapes for different medical applications.
The application required a robust vision control system to be able to respond to variations in positions of wires and tolerances of manufacture to produce defect-free stent welds. The control system had to be flexible to enable the creation of new geometries of weld, yet had to be simple enough for an operator to use with minimal training.
The FlexAuto machine vision and motion control software used machine vision analysis of weld zone images to refine the start and end locations of each weld trajectory. The image analysis algorithms incorporated a number of adjustable filter parameters, including tolerances on features such as size, aspect ratio and orientation of detected patterns. Once the weld start and end locations were found, the FlexAuto software executed the automated laser welding, controlling and coordinating multiple axes of motion based on weld patterns specified by the operator. The weld process parameters include settings such as weld voltage, frequency, pulse duration, and motion speed.