The customer was a supplier to major clothing retailer Marks & Spencer, who stipulate that all fasteners and attachments must be tested to failure.
The strength of the press-stud joint was critical to ensure that it met design tolerance and safety levels, particularly in baby clothing.
A motorized unit with a test speed was defined as 200 mm/min as the system needed to be simple to use in a production environment and provide consistent results.
The female part of the press-stud or 'popper' was placed under the retaining ring of the lower half of the Pull-Off fixture. The retaining ring was then locked in place by turning the lever of a cam mechanism.
The upper half of the fixture had an adjustable collet to fit over the male part of the press-stud. The collet was then tightened over the male part of the press-stud. The collet was then tightened to secure it in place. For ease of loading the male-press stud and to ensure a straight pull, the upper half of the fixture was connected to the force gauge via a flexible chain link.
The peak tension load to separate the press stud (or break the material joint) was captured on the force gauge display at the fast data-acquisition speed of 1200Hz.
S.R. Gent, Dewhirst Childrenswear, Coats Viyella
