Industrial 3D printing requires plastic materials that, as printed components, correspond to the performance level of injection-moulded components. This is the key to finding application for special components or in the spare parts market without major qualification effort and design adjustments. The standard materials in the plastics industry primarily include PP GF10, PP GF30 or PA6 GF30 – i.e. fibre-reinforced materials.
Powder bed processes such as laser sintering offer almost unlimited geometric freedom when printing components. It is necessary because the components originally designed for injection moulding have complex geometries. But reinforced polymers in powder form are a contradiction in terms. It can be made with fibres mixed dry into plastic powders. However, unbound, very thin fibres or mineral microscopically thin needles are risky to handle from an occupational safety perspective and for this reason do not receive internal approval from industrial 3D printing processors.
In cooperation with EVONIK (Germany), LEHVOSS (Germany) has now developed a PA613 with compounded carbon fibre reinforcement. The base polymer PA613 was designed by EVONIK specifically for laser sintering. As such, it is characterized by low moisture absorption, high temperature stability and – unlike PA6 – high process stability in laser sintering. The fibre reinforcement consists of high-strength XCF fibres, which have previously been used in LUVOCOMXCF products for injection moulding. When it comes to powder production, new approaches to particle technology were taken to preserve the fibre lengths in the individual particles as best as possible.
Printing the LUVOSINT PA613 9711 CF requires a build chamber temperature of 195 °C, which makes standard laser sintering machines suitable for processing. The material absorbs the wavelengths of CO2 diode or fibre lasers. “The fact that the first automotive OEMs have already qualified for spare parts production shows that we are on the right track. Nevertheless, in laser sintering, there still needs to be a lot of willingness to innovate in order to develop even more industrially relevant materials – including machines optimized for this – in order to bring industrial 3D printing into “series”!” says Dr. Marcus Rechberger, product manager for LUVOSINT at the LEHVOSS Group.