by Chad Jones, Sherry Laboratories
Injection molders and other plastic processors dealing with new materials or processes can use outside laboratories for routine quality control testing. Many organizations require testing to determine conformance to material specifications. More complicated projects can involve contamination testing and failure analysis. In many situations, obtaining test results from a third-party laboratory is often a necessity, especially when testing for safety.
Testing for routine quality control can involve a range of standardized tests. Many molders benefit from receiving inspection tests designed to confirm material before it is processed. These tests can be physical or mechanical in nature (e.g., density, tensile strength, impact strength). In the absence of internal specifications, parameters listed on the supplier’s lot certification can be checked to confirm the properties. It also can be worthwhile to prepare infrared spectra “chemical fingerprints” of materials to document consistency and establish baselines.
Examining material for contamination and determining root cause of failures are important and valuable services offered by commercial laboratories. Contaminations issues that have plagued materials and processes often can be resolved rather easily when the investigative tools of a laboratory are applied. A thorough documentation of an investigation into a failure will help support solutions to preventing further occurrences.
Laboratory test capabilities are numerous. Common tests include:
- Chemistry by Infrared Spectroscopy (FTIR)
- Thermal Properties by Differential Scanning Calorimetry (DSC)
- Coefficient of Thermal Expansion by Thermomechanical Analysis (TMA)
- Chemical analysis by GC/MS
- Chemical analysis by HPLC
- Density / Specific Gravity
- Filler type and content
- Impact Strength
- Tensile Strength
- Compression Strength
- Flexural Strength
- UV Light and Humidity Accelerated Weathering
- Fluid Resistance
- Heat Resistance
- Low Temperature Resistance
- Hardness
- Gloss Measurement
- Water Absorption
- Flammability
- Melt Flow Rate
- Cleanliness
Testing for safety may not simply be ensuring adherence to internal standards, but also determine conformance to a variety of regulations. Multiple government agencies, federal and state, evaluate and monitor plastic products for compounds determined to be harmful. Careful attention to current and developing regulations is important for molders, distributors and suppliers of plastic resin and products.
The technical services offered from commercial laboratories can greatly assist plastic molding companies and suppliers in efforts to introduce and keep high quality products in the marketplace. Whether it is for routine quality tests, compliance testing, contamination analysis, failure analysis or testing for safety, these services are well worth the time and resources required to complete.
Chad Jones is the manager of nonmetallic testing for Sherry Laboratories, Broken Arrow, OK. He can be reached at 918.258.6066 or chadj@sherrylabs.com. Visit Sherry Laboratories at www.sherrylabs.com. The full article can be found in the Summer 2011 issue of Plastics Business.
