Quality assurance for special plastics

TÜV SÜD has developed reliable and efficient incoming goods inspection on behalf of AGFA Gevaert HealthCare GmbH.

This inspection validates the special characteristics of the bought-in high-performance polymers.

(July 2010)

Medical engineering increasingly relies on modern special plastics as they offer flexible applications. AGFA Gevaert HealthCare GmbH, a supplier of integrated imaging systems used in radiology, mammography and orthopedics, processes bought-in components made of high-performance polymers. To verify compliance with the special quality requirements and the safe functioning of plastic components provided by external suppliers, including cogwheels, bushings, bearings and parts of casings, AGFA Gevaert HealthCare GmbH commissioned the plastics experts at TÜV SÜD Industrie Service to develop optimized incoming goods inspection.

"The key challenge was to validate the special characteristics of high-performance polymers within the scope of incoming goods inspection", explained Josef Vath from TÜV SÜD's Institute for Plastics. "After all, direct validation of physical, thermal and chemical parameters is generally too complex and not cost-effective within the scope of conventional incoming goods inspection." The TÜV SÜD experts developed a customized procedure for positive material identification (PMI) to ensure reliable and cost-efficient assessment of the functionality of the supplied components.

Positive material identification plus combined procedure

In the first step of PMI, TÜV SÜD Industrie Service prepares a fingerprint of the required type of plastic so that the experts can assess potential non-conformities, if any. The results of the individual tests are summarized in an analysis package which adds up to the fingerprint of a type of material. In the second step of the procedure, the components to be tested are analysed in detail. If the fingerprint complies with the reference spectra or curves, the component will be approved. Approval confirms the identity of the specified material type and thus ensures the characteristics required from the high-performance polymer. For analysis, the experts combine procedures such as infrared spectroscopy, thermogravimetry, differential scanning calorimetry (DSC) or X-ray fluorescence (XRF).

Through incoming goods inspection based on sampling, AGFA Gevaert HealthCare GmbH reduces the risk of processing unapproved materials in components which may result in their premature failure. As possible consequences of processing unapproved materials, the devices concerned may undergo a delivery freeze or be recalled – sometimes at considerable cost.

"Critical factors for quality assurance at AGFA Gevaert HealthCare GmbH are the assessment and monitoring tools along the entire value chain that are fine-tuned to each other", explains Josef Vath. "This reduces liability risks and permits reliable and cost-efficient quality assurance during incoming-goods inspection."