Friedrich-Alexander-Universität Erlangen-Nürnberg

Development of Thermoplastic Laser Sintering Materials for Engineering Applications

Development of Thermoplastic Laser Sintering Materials for Engineering Applications

Over recent years, additive manufacturing methods have grown to be established techniques in many area of product development, as well as production. The range of materials suitable for the current powder-based methods of additive manufacturing are however limited to few semi-crystalline thermoplastics, which means a significant restriction. Only powders based on polyamide 12 have been commercially available so far, with an average diameter of d50.3=60 µm. New laser sintering powders such as polyamide 11, which is a thermoplastic elastomer, as well as a polyetherketone, have recently been introduced into the market, and this is a clear indication of the relevance of material development. Nevertheless, with the choice of materials still limited today, there are considerable restrictions to the usage properties (e.g. mechanical properties, surface quality or temperature resistance) of components, and to the reproducibility of the parts produced.


So far, one of the main factors that influence powder-based additive manufacturing has been the polymer particles’ application behaviour, which is difficult to handle, and which directly affects the properties of the final component, and thus the process safety. This is one of the reasons why so few polymer powders are available for use at the market. The research project subject to this application is due to eliminate these present restrictions in terms of materials. Polymers will need to fulfil this fundamental requirement to enable designers to open up new areas of application for laser-sintered components. Mainly engineering applications in automotive construction are at the focus of the project. For this purpose, significantly improving components’ mechanical, thermal and optical properties by employing new material systems is of crucial importance. By meeting these targets, the investigations are due to achieve certain component properties the automotive sector requires, but which could not be achieved by laser sintering as yet. Research will particularly stress shortening the process chain in the long run by using additive manufacturing methods, so as to eventually enable direct manufacturing. Investigations will aim at enabling selective laser sintering to replace some conventional molding techniques in the long term, in order to develop new cost-efficient products, despite the increased number of different variants. Figure 1 provides an overview of the complexity in the range of materials and single parts, that exists in vehicle development.


In addition to opening up new markets, successfully developing new materials and processes will make the present cost structure less rigid. Only then can additive manufacturing techniques transfer from prototyping into economic serial production.


The project is due to utilize innovative methods of powder production and processing, in order to investigate new qualities of materials and components. In the first phase of the project, “Top-Down” techniques will be applied, such as the cryogenic grinding of pellets to generate powder. The powder will then be submitted to treatment, to make sure the particles sizes are distributed in a defined way. In a posterior treatment stage of atomization, the powder will then be spheroidized to provide for good pourability and bulk density.  The investigations’ long term target will be to obtain information at the same time, on how to generate spherical particles directly from pellets or semi-finished products (e.g. wire-shaped) by means of a melt spraying process.

Figure 1: Overview of the complexity in the range of materials and single parts, that exists in vehicle development [picture: BMW Group]


  1. D. Drummer, D. Rietzel, F. Kühnlein: Additive Fertigung - Vom Prototyp zur Serie, Tagungsband - Fachtagung Additive Fertigung (2009) S. 1-15.
  2. Rietzel, D., F. Kühnlein, and D. Drummer, Characterization of New Thermoplastics for Additive Manufacturing by Selective Laser Sintering SPE Proceedings ANTEC, 2010.


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