CASE
Surgical clip in Nitinol
The Surgical clips are used in Laparoscopy. Examples of applications are to close veins or blood vessels inside the body. These can be manufactured in different materials. In the present case, Nitinol (shape-memory alloy) is used which, besides having the property that it can be “programmed” to regain a desired shape, it has super-elastic properties that enables opening and closing it.
There are high demands on surface integrity. The product must be free of burrs and oxides. Previously, the customer has processed these products with a water jet guided laser. This has limitations with a machining speed of about 30 mm/min and heavy slag formation. Subsequent electropolishing was required. Alternative machining methods was performed with Finecut micro abrasive waterjet machine from Finepart Sweden AB with the below conclusions.
Data
Material
Material thickness
Length of cut
Annual volume
Nitinol
1.1 mm
138 mm
5 000 pcs
Cutting with Finecut machine
Cutting system
Number of set ups
Average cutting speed
Operational cutting time
Finecut operational cost
FAW200
1
72 mm/min
110 sec
0.49 €/pc
Conclusion from the Finecut test
- Sections of the part is down to 100 µm wide.
- The components show no generated burrs, oxides or heavy slag formation after cutting
- The typical tolerances of component are within ±10 µm
- No changes in the material structure after the cutting
- Surfaces were polished with Finespin magnetic polishing
