Providing worldwide interlaboratory testing since 1971


Plastics Program History

In the late 1980's, resin producers, automotive suppliers, molders, and independent testing laboratories all faced a similar problem: how to prove measurement accuracy when conducting quality assurance tests on plastics and films. With traditional destructive testing there were few reference materials available to verify instrument performance. The use of in-house control materials, while a valuable quality assurance tool to maintain day-to-day consistency of measurements, did not evaluate a lab's ability to make measurements that agreed with other laboratories. Some companies attempted to determine the accuracy of their measurements through a round-robin program among three or four other facilities. This was often unsuccessful because the small number of participants made it difficult to determine a consensus value with a high degree of confidence.

Members of the industry who were aware of CTS’ other interlaboratory programs contacted CTS in the spring of 1991, and all parties agreed to meet at the next American Association of Laboratory Accreditation (A2LA) Assessors’ Conclave. Events progressed very quickly. At the A2LA meeting CTS learned that there were many labs being accredited for plastics test methods with no proficiency testing available to them. A2LA auditors approached some of the D20 members, who then indicated they felt that CTS was the best and most likely organization to get a plastics testing program up and running. The chair of D20 appointed three committee members to serve as the CTS program’s advisory committee, and three test methods were selected for the initial program – tensile properties, DTUL, and flow rates. Thus, the CTS Plastics Program was initiated in 1992 at the request of industry, ASTM committee D20 and accrediting bodies. While initially the plastics tests were incorporated into CTS’ existing Rubber Program, it quickly became clear that there was little in common between the two programs. In 1994, the CTS Plastics program was established as its own separate entity.

Not only did the number of tests offered grow from the original three to more than 20, subproperties have been added to and refined in most tests to meet the needs of a demanding and changing industry. Film testing, which was added several years ago, attests to just how much more future there is in plastics for interlaboratory testing.

Today, participation in the CTS Plastics Program assesses laboratory performance by comparing each participant's results to a consensus value based on the results from as many as 100 laboratories testing the same material. An additional benefit of the CTS program is the use of "blind" samples. As the participant does not know what the result should be, the CTS program is a true assessment of the testing process including sample labeling and preparation, instrument operation, and calculation of the test result.
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