MEDICAL CRIMPING

Challenge

The original application – which experienced serious quality problems – was the pressing and monitoring of a small ID metal cylinder tube that was already inserted into one of a larger ID in a crimping process which:

• Joined medical catheter parts
• Provided a means of verifying a precise crimp

A medical equipment manufacturer had serious problems with the original catheter assembly technique. The two metal tubes, once crimped (see above photo), were often too loose, which made the catheter pull apart, or were too tight, which did not allow fluids to pass.

The customer found that the problem was due to a hydraulic press used in the crimping process. They were not able to control the force with the precision needed. An attempt was made by the customer to use an external load cell, which they felt would allow them to retract the press once a certain force was reached, but this proved to be unsuccessful.

Solution

Promess offered an electro-mechanical solution that solved the problem, the Promess Electro-Mechanical Assembly Press (EMAP). After Promess Application Engineers found the proper forces required to crimp the catheter, the EMAP allowed the customer to press to the same force (+0.5%) every time. With closed-loop feedback from external transducers built into the fixturing/tooling, the Promess EMAP solved the monitoring problem too, because it measures the assembly as it is being made.

The customer now is capable of verifying that every catheter is produced to the proper specification and that the force needed to crimp the tubes together is within the proper range. This results in a 100% effort certification which shows that every catheter produced will function properly.