Production Processes - Rapid Prototyping, Tooling and Manufacturing

Since the creation of the spin-off company Materialise, the research on additive manufacturing has mainly concentrated on stereolithography (SLA) and selective laser sintering and melting (SLS/SLM). A patented SLA liquid curtain recoating system has reduced the time needed for depositing successive liquid layers by a factor of ten, yielding a proportional reduction in production time. Major advances are made in direct laser sintering of high strength metal powders like steel, titanium, tungsten carbide and other materials. The application of these material addition processes to actual manufacturing (so- called Rapid Manufacturing) is mainly focussing on tool manufacturing (Rapid Tooling), aerospace manufacturing (a/o production of light-weight hollow structures) and medical prostheses (dental prostheses, scaffolds). A major break-through has been achieved in rapid manufacturing by moving from SLS to SLM.

New rapid prototyping methods for sheet metal forming are also being investigated, such as laser bending and single point incremental forming.

More information about :

• Stereolithography
• Selective Laser Sintering and Selective Laser Melting

A skull built for medical purposes by stereolithography.

Stereolithography

Stereolithography is a layer-by-layer additive manufacturing process, based on photopolymerisation. Parts are built up in successive two-dimensional layers created on top of each other. The materials used are photo-curable liquid monomers, which polymerise under influence of UV-radiation of a specific wavelength. Past research involved design of laser-based stereolithography machines and the design of patented system for deposition of liquid layers: the curtain recoating system. In this system, the liquid resin is extruded out of the slot of an extrusion head, and it falls down onto the build platform as a liquid sheet, also called a liquid curtain.

Current research involves optimising the curtain recoating system in order to decrease the thickness of the deposited layers and to increase the layer quality. Currently, layer thicknesses of 0.12 mm are achievable. A capacitive measurement system has been developed in order to measure thickness non-uniformities in the liquid curtain. These measurements led to a redesign of the extrusion head for curtain recoating, resulting in a more uniform liquid curtain. In addition, the feasibility of high-speed curtain recoating, with coating speeds of more than 1 m/s is investigated.

Other research involved the development of software for easy production of SL parts (STL-based feature recognition, rapid tooling software), the development of new stereolithogrephy materials (glass reinforced resins) and the manufacture of stereolithographic mould inserts for rapid tooling applications.

Selective Laser Sintering and Selective Laser Melting

Below you can find a list of the different topics in our research group 'SLS/SLM'.

• Material growth technologies - Rapid Prototyping, Rapid Tooling and Rapid Manufacturing
• Rapid Manufacturing for Aerospace
• Medical applications of Rapid Manufacturing