“Stiction” and Tack testing

“Stiction” and Tack testing

“Stiction” and Tack testing

The word “stiction” is a portmanteau of the term static friction and, perhaps, the verb ‘stick’, so when a customer called looking to perform a stiction test, we were understandably confused when he described a modified tack test.

The customer wanted to press their test samples onto a number of different substrates, to a predefined force and hold it at that load for a defined period of time. Once that dwell time has elapsed, the customer wanted to pull the specimen off the substrate and simply record the maximum force.  This sounds easy enough until you consider the hysteresis of the loadcell in going from positive to negative loads, and grips that work in both tension and compression with absolutely no slippage of the specimen while going through the zero load point.

Horizon Screen shot for stiction

 

The Tinius Olsen solution to our customer’s ‘stiction [static friction]’ problem was to use a modified drill chuck that eliminates any movement of the test specimen while going from compression into tension, and our precision loadcells that have negligible zero point hysteresis. The final system solution included a new model 5ST, a lower grip platform with interchangeable substrates and the modified drill chuck; the system was ‘tied together’ by our Horizon software which allows development of sophisticated testing routines by a supervisor (and simple one click operation by the operator), and the generation of custom reports for the QC department’s record keeping.

There are, potentially, multiple applications and customers for this type of test, including manufacturers of Post-It™ notes, sticky back products, suction pads, sticky labels, blue tack, removable tapes, sticking packaging wrappers, plastic bags etc.