Ethicon, part of the Johnson and Johnson Group, are a world famous manufacturer of sutures. Some years ago whilst visiting their Edinburgh site, to discuss the purchase of a second Hounsfield Tensile Tester, I was asked if the Company could help solve a problem they had, proof load testing, the needle to thread bond strength.

Background

Each operator had their own work station where they would produce and test hundreds of sutures. To test the bond strength they were using a see-saw type of arrangement with a weight which could be positioned closer to or further away from the pivot point to increase or decrease the force required to lift the weight to the top of the see-saw. Each type of suture would have its own specified proof load. The operators would make hundreds of sutures and test very quickly by sliding the suture through a slot on the opposite side of the see-saw and raising the weight on the other side to the top. Each test would take around a second.

The Problem

If the bond failed, it was not possible to determine the actual failure load. Secondly, if the operator pulled too quickly, the jarring when the weight reached the top of it’s trajectory.

The Solution

Discussions took place; Hounsfield listened to the problem and offered to produce a prototype LF100 proof load suture tester. The instrument would allow the operator to pre-set the required proof load. Once this load was reached an audible “beep” would sound to inform the operator the test was satisfactorily completed. There was also an LCD display. If the suture failed a double “beep” would sound and the failure load would be recorded and saved in the instruments memory. If the operator was too heavy handed it could result in a bond looking good but weakened due to the shock load it had experienced. The instrument thereby “taught” the operator how fast to pull.

The Result

100% testing with the LF100 improved quality and market share for Ethicon resulting in more staff being required. Ethicon subsequently purchased around 350 LF100’s and 5 more Universal Testing Machines.