Material quality, consistency, and reproducibility–from part to part and batch-to-batch–is a key to the use of additive manufacturing (AM) in a production capacity. Various AM vendors are developing standards to verify materials, technologies, equipment, and processes according to industry needs.
For example, EOS has a quality management system to verify material consistency. It includes elements that have a direct impact on the quality characteristics of components made with additive manufacturing.
For the manufacture of the basic product for the plastic Polyamide 12, EOS worked closely with Evonik Industries. The starting material was subjected to an extensive and documented quality assurance procedure even before it was delivered to EOS.
Thomas Große-Puppendahl, Manager of the Engineered Products line at Evonik: “Based on our manufacturing method and experience in powder technologies, we are able to create a suitable basic product for laser sintering materials. Our quality management system covers all relevant inspections of polymer and powder indicators, such as free-flowing properties, powder density, melt and cooling behavior and process suitability tests.”
The refining process was performed on EOS equipment after the acceptance test and an additional incoming goods inspection. Defined quality assurance activities are carried out during and after the finishing process. If all criteria are met, a test report is prepared pursuant to ISO 10204 – with additional fire testing for fire-resistant materials.
In addition to testing the material, specimen and tie bars are manufactured on EOS laser-sintering systems. Products are shipped to the customer once a batch has passed both test instances. The corresponding test report, which meets the European and international standard EN 10204 3.1 documents the test results that are relevant to the customer.
The AM systems are also subjected to quality assurance measures, which are documented in line with the EOS machine acceptance process, during which the defined reference build jobs are prepared and subsequently checked for a number of authoritative criteria, such as mechanical properties and dimensional accuracy. These checks are performed in accordance with the current valid international standards.
The build process using the appropriate EOS parameter set forms another important element for securing uniform component quality. Standard parameter sets are created during the material development process, and then three build jobs are performed on three laser sintering systems with three powder batches to ensure consistent part quality.
EOS offers a material data sheet with a detailed description of the material properties that can be achieved for each material on the quality basis. The properties include mechanical indicators for tie bars, which are manufactured in all three spatial directions. The relevant material data base can be found here.
EOS
www.eos.info
