Standard & Custom

Press Leaders

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ASTM standards for materials testing are applied worldwide to ensure that the measurement of the physical properties of materials are representative and comparable to each other. Rubber and plastics have highly diverse properties; so for industries that use or manufacture rubber and plastics, ASTM standards play a vital role in ensuring the reliability of information used to make decisions regarding materials. In this article we take a look at how ASTM standards are used for testing of rubber and plastics, and how presses ensure that these standards are rigorously adhered to.

Formerly known as the American Society for Testing and Materials, ASTM International is responsible for defining over 12,500 technical standards designed to improve product quality and safety globally1. ASTM standards are defined with the help of over 140 technical standards-writing committees, with members hailing from over 140 different countries. These standards are of global influence: More than half of ASTM standards have been adopted as the basis for national standards in the USA, or are referenced in regulations in countries outside the USA.

The scope of the work of ASTM International includes the definition and maintenance of a large number of standards for mechanical testing2. The range of ASTMS applications is very broad, and each application has its own numbered ASTM National Standard. Standards in testing are vitally important, and organizations in the USA and worldwide rely on these standards to ensure that their mechanical testing procedures are rigorous, accurate and consistent with each other.

Hydraulic Presses play a crucial role in the definition of these standards: as the means by which a controlled force can be applied to different materials and components, presses are the true workhorses of the physical testing world. In addition, presses are routinely used in ASTM standards as the means by which plastic and rubber test samples are produced. The use of high-performance and high-precision presses means that manufacturers and testing organizations are able to ensure quality and reliability by adhering to ASTM standards.

The Importance of Mechanical Testing and Sample Preparation of Rubber and Plastics

Physical property testing is of special concern in industries that use rubber and plastics. The mechanical properties of plastics and rubbers are highly variable, and the exploitation of these spectra of properties lies at the core of much of modern technology. Countless industrial and consumer products rely on the electrical, chemical and mechanical properties of these materials; so mechanical testing of rubber and plastics to the relevant standards is therefore crucial for the development of products. One example of how an ASTM standard is used for mechanical testing of plastics is in the preparation of test samples. ASTM standard D4703, for example, describes how isotropic test-samples of thermoplastic materials can be compression molded in a press3. This ASTM standard outlines how homogeneity can be achieved sample, which is essential for accurately measuring material properties via force testing. Another standard, D3182, describes how molded rubber test samples can be reproducibly manufactured in a press.

By adhering to standards such as D4703 and D3182, manufacturers can ensure that their measurements of the mechanical properties of materials are accurate and comparable, which allows them to make optimal materials decisions when developing products. This makes ASTM standards useful for virtually all quality control, material comparison and research and development applications.

According to ASTM standards definitions, rubber and plastics are formed into a variety of shapes for mechanical testing, including test plaques, bar specimens and rubber sheets. All of these are typically produced using a press to ensure consistent and accurate results.

Precision Presses for ASTM Testing

In order to comply with ASTM standard specifications involving presses, it’s crucial that the press used is capable of providing the required force with sufficient precision, and also, where applicable, of providing the requisite heating or cooling via thermally-controlled platens.

Wabash MPI manufactures a range of high-performance presses which are configured specifically to be used for the production of test samples according to ASTM standards. For example, the Genesis Series Hydraulic Compression Press Model G30H-12-ASTM has been developed specifically to process samples according to the D4703 standard above4. Thermal control of the platens means that this press is capable of carefully controlling the cooling rate of the samples in compliance with D4703 specifications. Another Genesis model, the G50H19RASTM, is specially developed for the production of molded rubber test samples in accordance with ASTM specification D3182, also detailed above5. This press has an adjustable clamp force of 8 to 50 tons, and features fully guided, electrically heated 19” x 19” platens with operating temperatures up to 500°F.

All Wabash presses are constructed to exacting standards and can be augmented by a range of accessories, including larger heated platens and vacuum shrouds. Wabash MPI also provides a range of field services including new equipment start-up, preventative maintenance and calibration of our equipment. Their presses are now available up to 2500 ton capability.


References and Further Reading: 1. ASTM International - Standards Worldwide. Available at: https://www.astm.org/  (Accessed: 21st December 2019) 2. Committee E28 on Mechanical Testing - Scope. Available at: https://www.astm.org/COMMIT/SCOPES/E28.htm  (Accessed: 21st December 2019) 3. ASTM D4703 - 16 Standard Practice for Compression Molding Thermoplastic Materials into Test Specimens, Plaques, or Sheets. Available at: https://www.astm.org/Standards/D4703.htm  (Accessed: 21st December 2019) 4. MPI, W. Genesis Press for Polyethylene Sample Preparation. Available at: https://www.wabashmpi.com/images/PDFs/D4703.pdf 5. Wabash MPI Hydraulic Presses for ASTM Test Sample Molding. Available at: https://www.wabashmpi.com/news/157-wabash-mpi-hydraulicpresses-for-astm-testsamplemolding  (Accessed: 21st December 2019)