Evaluating scuff resistance
Examining the SATRA test equipment on which this assessment can be conducted.
Image © TravisPacheco | iStockphoto.com
There are a number of ways that scuffing actions can damage footwear – or footwear can affect other items. The causes of damage to footwear are numerous, including coming into contact with a range of surfaces encountered in walking. Some problems are the result of one-off incidents (such as striking a kerbstone), whereas other damage is caused over a considerably longer period by repetitive contact.
While it is not possible to prevent all damage from occurring, it is possible to ascertain if a material provides a good level of resistance to scuffing, depending on the application for which the footwear is intended.
Some types of footwear are particularly liable to exposure to scuffing – for example, children’s footwear, safety or industrial boots and footwear for military applications. These will typically require more severe scuffing tests than for general, everyday footwear. SATRA has developed a test method and an associated test machine that can be used to simulate the damage caused in situations encountered in use.
The SATRA STM 423 chisel scuff tester
SATRA TM140:2021 – ‘Scuff resistance – chisel method’ is a very challenging test for a material, and it reproduces severe snagging. The test is too severe for many materials, and is generally used only for those claimed to have a high level of abrasion resistance such as polyurethane (PU)-coated leather and heavy-duty coated fabrics.
The assessment can be conducted using the SATRA STM 423 chisel scuff tester (figure 1). The test specimen is mounted on a turntable and clamped down. A weighted metal chisel head is lowered carefully onto the surface of the material as soon as the specimen begins to rotate, and is lifted off before the rotating turntable is stopped. The test is terminated when a small amount of the coating is completely removed, exposing the underlying substrate. The number of revolutions required is used to classify the material being tested with regard to its abrasion/scuff resistance – whether ‘moderate’, ‘good’ or ‘excellent’.
Selecting the appropriate test – and the correct test machine – for a particular type of material and its application is important to obtain meaningful assessments of products with respect to their resistance to scuffing.
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This article was originally published on page 20 of the October 2022 issue of SATRA Bulletin.