New Martindale abrasion tester

Describing this newly developed version of the popular test machine.

by Peter Allen

SATRA has developed a new version of its highly successful Martindale abrasion tester. Designated STM 633, the new four-station machine has evolved from the current STM 604 Martindale abrasion tester, which has been giving reliable performance to SATRA customers for many years.

The operating principle of the Martindale abrasion tester was first developed in the 1940s by JG Martindale, while he was working for the UK’s Wool Industries Research Association. His developments were prompted by a need to create a more realistic method for assessing the wear resistance of textiles. The test machine which now bears his name is universally recognised as an effective way to assess the wear resistance for a diverse range of materials, including those used in the construction of footwear, garments, personal protective equipment (PPE) and upholstery.

Over the intervening years since the machine was first developed, a range of test methods have been established which describe how these wear assessments are to be conducted. A number of test methods have been developed which take advantage of the inherent versatility of a Martindale abrasion tester. Typically, a test method will specify the geometric requirements for the abradant table and the specimen holder, the applied weight, the abradant material and any associated underlay. It will also describe whether the test is conducted wet or dry, the speed of the test and the number of cycles for the test and or inspection intervals.

Fundamental to the action of a Martindale abrasion tester is the relative motion between the specimen and the abradant. This is defined by the creation of a ‘Lissajous’ figure of a set dimension formed after a number of test revolutions. In addition, the abradant table and the specimen holder need to be kept parallel to each other during the course of the machine operation. For some tests, the abradant and specimen are reversed, with the specimen material located in the fixed table and the abradant held in the moving specimen holder.

Test methods also indicate the assessment criteria for reporting the visual examination of the abraded specimen or in some cases mass loss. The SATRA TM31:2003 – ‘Abrasion resistance – Martindale method’ test is an example of a method used for the assessment of a variety of materials, including fabrics, coated fabrics and leather. It is widely used in the footwear industry.

EN ISO 20344:2011 (‘Personal protective equipment –Test methods for footwear’) clause 6.12 (‘Determination of abrasive resistance of lining and insock’) is another example of using a Martindale abrasion tester to conduct abrasive resistance tests. For textiles, EN ISO 12947:1998 – ‘Textiles – Determination of abrasion resistance of fabrics by the Martindale method’ is commonly referenced. An example of a Martindale test where an aggressive abradant is used is EN388:2003 – ‘Protective gloves against mechanical risk’. In the Martindale test specified, the abradant used is 300g/m² glass paper.
Martindale abrasion testers may also be used to assess the susceptibility of a material to form ‘pills’ – small balls of tangled fibres on the abraded surface, sometimes known as ‘bobbling’.

SATRA STM 633

SATRA has a long track record in design and manufacture of Martindale abrasion testers stretching back to the 1950s. The latest SATRA STM 633 machine builds on the experience in design and manufacture and extensive experience gained from the use of SATRA Martindale abrasion testers in our own test laboratories.

The design of the new STM 633 Martindale abrasion tester was targeted on simplification of the machine, while retaining the reliability, durability, accuracy of operation – along with ease of assembly and maintenance – associated with SATRA machines. One outcome from this process is a more compact machine than its predecessor, which requires fewer parts used to achieve a particular functionality. Particular attention has been paid to simplifying the process of table alignment and maintenance of table alignment.

The STM 633 incorporates the well-proven SATRA ‘Smart Drive’. This microcomputer drive technology provides accurate control over speed, torque and cycle counting, contributing to consistency of testing. A number of accessories and consumables are available from SATRA for the STM 633 test machine to meet the requirements of the individual test methods, including a ball plate assembly used for the assessment of the abrasion resistance of leather.

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Publishing Data

This article was originally published on page 36 of the December 2012 issue of SATRA Bulletin.

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