Wednesday, October 21, 2009

Guidewire test

Guidewires are inserted in a patient to the spot where a catheter or other tube must go. The medical tube is then inserted over the guidewire. Coatings increase lubricity, reduce the risk of infection or add other desired characteristics

Following tests were done to characterize Guidewires .

(i) Friction Test: The test performed with wire-on-wire (cross cylinder mode) Two pieces of the same test specimen was used. One piece was be placed over the other at 90 degree angle, and moved over each other in reciprocating mode with low controlled  load to obtain coefficients of friction (COF).

(ii) Wear Durability Test: This test  used similar cross cylinder schematic as the friction test above.   COF, electrical resistance and the time of coating failure of all samples was recorded.  

(iii) Scratch Adhesion Test: The test consists of scratching the coating with a flat side of WC microblade with a linearly increasing load over known distance. Friction force (Fx), normal force (Fz) and electrical resistance data was recorded to obtain the scratch adhesion property of coated wires at the load at which electrical resistance and COF exhibit a sudden change of all  samples.   

(iv) Hardness Test: Hardness 

The data was very interesting and conclusive. It took us a week to get the above mentioned tests done. The biggest issue was to mount these guide wires (our one engineer figured out a smart way)

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