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Revised footwear test machines

Testing the flexing properties of footwear

28th September 2017

SATRA has made improvements to certain machines used to test the flexing properties of footwear components, materials and whole shoe.

A number of footwear-related tests require materials to be flexed at low temperatures. SATRA provides a range of machines that incorporate a low temperature cabinet to enable tests to be carried out to determine the suitability of materials when assessed at temperatures below 0ºC.

Several of SATRA’s low temperature test machines – including the STM 141F Ross flexer, STM 184F whole sole flex machine and STM 477F Bally flexer – have recently been revised. These revisions include simplified drive mechanisms in order to reduce machine noise.

The Ross flexer has also been adapted to accept flexing at 60 degrees as called up in a number of specifications. Ninety-degree flexing is still available to suit test methods such as SATRA TM60:1992 – ‘Ross flex test – resistance to cut growth on flexing’. A new motor has also been fitted to machines that were previously manually jogged, so introducing a push-button jog facility.

To ensure operator safety, SATRA’s low temperature cabinets have the electrical control and drive systems outside the freezer area where moisture cannot impair electrical safety. The control system incorporates a digital temperature controller that can be set to achieve the desired temperature (from ambient down to -20ºC), plus a counter to indicate the number of flexes carried out. The counter can be preset to stop the drive mechanism when completed.

An important requirement in standards such as EN ISO 2034 is that both metallic and non-metallic inserts incorporated into the soles of safety footwear to prevent nails penetrating through to the foot need to be assessed for flex resistance. SATRA's midsole flexing machine, designated STM 441, has been updated to incorporate higher-grade pivot point bearings to increase periods between maintenance. STM 441 is a six-station machine and the angle of flex can be adjusted to meet the appropriate standard. A timer is provided to stop the machine once the required number of flexes has been reached in order for the inserts being tested to be inspected. The machine is designed to operate at 16 cycles/second.

Please contact test.equipment@satra.com for further information.