Lighthouse project for innovative production of replacement and serial parts – Fraunhofer IGCV

Additive manufacturing has become increasingly important for production technology in the last few years. In particular, laser sintering (LS) has made a major step towards mass production of individualized products in the automotive industry, for example. However, the vertical and horizontal integration of additive manufacturing processes into conventional lines has only been implemented to a limited extent. Reasons are a lack of cross-process chain standards and low levels of automation in the machining and transport processes. For example, little attention has been paid to component cleaning and the detection of impurities so far.

An advantage of additive manufacturing is the possibility to generate complex structures, followed by the disadvantage of process-related accumulation of contaminations on filigree components that are difficult to access. This can be relevant for additive manufactured plastic components, for example, which react to even the smallest contaminations by impairing their function and service life.

 

Digitalized production lines for the automotive industry desired

In the automotive industry, there is a growing desire to fully exploit the high potential of additive manufacturing processes in series production lines. In the future, this will reduce process time and susceptibility to errors and increase product quality. The POLYLINE project, funded by the German Federal Ministry of Education and Research, brings together 15 industrial and research partners from Germany to develop a next-generation digitized production line. The aim is to complement conventional manufacturing techniques (e.g. machining, casting, etc.) with Additive Manufacturing (AM) in the form of high-throughput production line systems. In this way, a continuous digital process chain will be created from process preparation through the LS process, cooling and unpacking as well as cleaning and post-processing of the parts (see Fig. 1).

© G. Katsimitsoulias, Fraunhofer IML
Image 1: Schematic representation of a laser-sintering production line

Ultra-fine cleaning and cleanliness analysis necessary

In addition to production planning and control, the Fraunhofer IGCV is involved in the research project with the topic of technical cleanliness. Here, research is being conducted into how LS- components can be brought to a defined state of cleanliness – required for finishing process (e.g. dyeing, bonding, etc.) and use in the field – in particular by defining cleaning process chains. Among other things, this should provide foundations for further interdisciplinary research and development work in the fields of additive manufacturing and technical cleanliness by 2023. The use cases include personalized components as well as series components in large quantities.

 

Through close cooperation between industry and research, it was already possible to define the requirements for technical cleanliness and to develop a concept for precision cleaning within the first year of the project (see Fig. 2). These investigations also showed that ultrasonic cleaning and cyclic vacuum cleaning have major potential for component reconditioning. The measurement technologies available on the market for detecting and classifying plastic particles are not adequate for application in additive manufacturing and need to be expanded. Based on this work, further parameter studies are currently being carried out. Furthermore, cleanliness limits for the coloring and bonding of additively manufactured plastic components are being developed.

© Fraunhofer IGCV
Image 2: Ultra-finde cleaning concept using the example of a personalized component