Data on physical properties of plastics such as tensile, flexural, compressive, tear, and shear strength that can help optimize material formulations, processes, and quality control, can be determined using a universal testing machine.
Additionally, other testing equipment can be used to establish rheological properties, weatherability, color, and appearance as part of a complete quality program. Advances in electronics and data acquisition and analysis software have improved their performance, ease-of-use, and even have led to more attractive pricing.
Product development is among the key reasons compounders and resin makers perform any kind of test. Other reasons include testing material to determine its suitability for a variety of processes and whether its properties will meet the particular end-use application, as well as for quality control of the manufacturing process to maintain consistency of that process.
Traditionally, manufacturers have relied on their material suppliers for physical property data, but the necessity for real-time, reliable test data on incoming raw material, various stages of their manufacturing process, and on the final product has meant that more and more processors are setting up test labs. Understanding and adjusting the manufacturing process and material characteristics can pay back huge dividends in reduced scrap and rework.
All testing is done in accordance with specific ASTM and/or ISO standards (or other internationally recognized standards organizations or industry standards) so that the resultant data is transportable and comparable. This should not be confused with ISO 9000, and its variants. ISO 900X certification states that you have a traceable documentary and recording program, but if you have stated that you manufacture substandard product and can prove that your product is substandard, then you can still be ISO 900X certified.
Universal testing machines (UTM) allow one to stretch, bend, squash, peel, tear, puncture, or shear a specimen until it breaks. By far the most common tests performed on plastics with a UTM are tensile strength (and modulus) and flexural strength (and modulus). The need for this type of testing equipment is also recognized when considering product liability, should any product be questioned.
Rheological properties are typically studied to ensure that the incoming material is going to perform as expected in the manufacturer''s production process. If equipment is set to work with material that is out of tolerance or specification, this will mean costly downtime to clean and reset all equipment.
Color and appearance must also be checked to ensure that product looks the same. For example, bags of chips on a supermarket shelf may have come from multiple sources, even though they''re a single brand. If there is a difference in the color of the packaging, one source could be perceived as being older or stale and as a result, no product from any source would move.
Wayne Hayward, corporate marketing manager, Tinius Olsen Inc. [email protected]