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Stents
Automated 100% control of inner and outer surfaces
Simple stent structures are braided out of a metal wire or formed and welded. Complex lattice textures are cut with a laser out of a tube.
To ensure the patient´s safety, any type of stent has to fulfill highest quality standards. The stent surfaces must be absolutely free of contaminations and defects. This requires a reliable visual 100% inspection of the inner and outer surface, which allows different types of stents to be measured non-destructively within the production chain.
Applied measurement system:
µsprint sensor: Measurement and defect detection of a wohle stent within seconds
The NanoFocus µsprint sensor is ideally suited for the requirements of automated non-contact control of stents. The fastest confocal sensor worldwide, which is based on the patented µsprint Technology, allows with more than one million measurements per second the extremely fast acquisition of surfaces with high throughput rates. Other automated inspection methods often have Problems with reflections that are caused by the simultanious exposure of the inner and outer surface of the stent. Confocal methods such as the µsprint sensor avoid these problems by using a filter technique that does not allow these reflections. Therefore and because of ist high numerical aperture, the µsprint sensor can transfer 360° of the stent surface into real 3D data – inner and outer surface as well.
Measurement and defect detection of an entire stent is completed within less than 30 seconds. The µsprint Technology does not require any sample preparation. Another advantage of the robust optical sensor is the direct Integration into the production line or any testing system. Therefore, the state-of-the-art stent inspection system NSI-7, developed by NanoFocus Partner GDO B.V., is equipped as Standard with the µsprint sensor.
Measurement and analysis:
Fully automated defect detection and analysis
For the cmpletely automated inspection, a stent is put over a pin, pressed on a gummi belt and rotated. The motorized z-axis sinks the µsprint sensor into the first focus position. While the belt twists the stent on a second pin, the measurement system acquires the entire outer lattice structure. The sensor thereby stays in a fix position. Afterwards, the Transport belt is driven in the opposite direction to inspect the inner surface (second focus position) of the stent. The measurement data is displayed seperately as an intensity and height image as well as a 3D image on the system monitor.
The following defect types can be detected automatically:
- bends
- pits/ dents
- foreign matter/ contamination
- cutting failures
- excess metal/ Islands
- grooves/ damages
- polishing anomaly
The image data processing algorithm automatically evaluates the imaga data and denotes all defects that are above individually adjustable tolerances. The results are recorded for consistant traceability.
