SATRA's Bally test machines
An overview of how this important range of equipment is used to evaluate products in the physical testing laboratory.
SATRA manufactures a wide variety of test machines as vital technical support in the production of high-quality goods. For example, the ability to assess the water resistance of upper materials is essential when designing and producing footwear for certain applications. SATRA can supply test machines that are used to ascertain this characteristic, including the following items of equipment.
SATRA STM 703 Bally penetrometer
The four-station SATRA STM 703 Bally penetrometer is used to conduct a number of nationally- and internationally-recognised methods for measuring the dynamic water resistance of leathers and synthetic materials. Its unique action ensures that each test piece is assessed under the conditions relevant to the stiffness of the specimen.
A rectangular specimen – with the side which will be exposed to water in the finished footwear facing outwards – is curved partly around and secured between two solid cylindrical clamps to form a trough. A water-filled tray is then raised to partially immerse this trough, and the clamps are oscillated at a constant speed so that the specimen is repeatedly flexed. The amount of dynamic movement (‘amplitude’) is adjustable, according to the stiffness of the material, which should first be measured on the SATRA STD 704 Bally stiffness meter.
While penetration of water can be visually detected, a significant feature of the SATRA Bally penetrometer is the electronic water detection system which removes the need for constant operator attendance during testing. This feature also includes a counter and alarm for each of the four stations. Water detection relies on a resistance being reached in the electronic circuit. Copper mesh is placed in each specimen and a probe forms the link between the electronic circuit and mesh. When water penetrates the specimen, the resistance changes and automatically stops the station counter while sounding an alarm. Testing continues on the other stations until water penetration is detected at all stations, when the machine stops.
The ability to adjust the amplitude and the adjustable electronic water detection system are features unique to the SATRA STM 703 Bally penetrometer. Other features on this unit include an electronic counter on each station and a master electronic counter.
SATRA STD 704 Bally stiffness meter
The SATRA Bally stiffness meter measures the stiffness of material before testing on the SATRA STM 703 SATRA Bally penetrometer.
SATRA STM 706 Bally permeometer
The SATRA STM 706 Bally permeometer assesses the water resistance of heavy leathers, particularly sole leathers and other components such as insole boards. It is used for the only internationally-accepted method for determining this property. This machine utilises a dynamic motion during the test which closely corresponds to the conditions experienced during wear. The test piece is repeatedly bent and laid flat again under load, as a shoe sole is during walking, while it is kept in contact with water on one of its sides. The penetration of moisture through the test piece is automatically detected and reported by an acoustic or visual signal.
By using this unique piece of SATRA Bally test equipment, it is possible to determine the time taken for the water to pass through the test piece, the quantity of water absorbed by the test piece within different time intervals, and the quantity of water passing through the test piece and given up on to an absorbent layer within a defined time limit (permeability).
SATRA also supplies consumables for a wide range of tests applicable to leathers, textiles, rubbers, finished footwear, leathergoods, gloves and PPE.
How can we help?
Please email firstname.lastname@example.org for further information on SATRA Bally test machines and to purchase these items, and visit the web page at www.satra.com/test_equipment for an overview of SATRA’s extensive range of test machines and devices.
This article was originally published on page 16 of the January 2023 issue of SATRA Bulletin.
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