3D Printing without Support Structures
The Fraunhofer Institute for Laser Technology ILT has now developed the TwoCure process to industrial maturity: the resin-based 3D printing process enables the large-scale production of unsupported components in an automated process.
Until now, support structures were indispensable for resin-based 3D printing since the frequently delicate plastic structures have to be supported through contact with a platform. The unwieldy support structures require prior CAD planning and must be removed after printing. As part of a government-funded project, researchers at the Fraunhofer Institute for Laser Technology ILT have developed the alternative TwoCure process in which liquid resin is applied layer by layer to previously solidified resin. Based on a similar principle to a projector, an LED light unit projects the component’s layered geometry into a liquid resin bath that hardens in the illuminated areas. At the same time, the cooled machine ensures that the layered component freezes into a block together with the wax-like resin. The resin can then be liquefied at room temperature, draining off the support material. All that remains are the 3D-printed components, which only need to be cleaned briefly and post-cured.
The technology is of particular interest to companies that produce many small individual plastic components or limited production runs up to batch sizes of 1,000. For example in future, one plant could produce several hundred individual earmoulds for hearing aids, moulds for jewellery production or small batches of plastic components daily. Until now, manufacturers required several 3D printers for this level of throughput.
Economical small batch production
In addition, the new process allows components to be positioned without any platform contact. 3D components can be built directly at any point within the build volume and no longer require support on the platform. This allows better use of the total build volume and the production of significantly more parts per 3D-print job.
Handling is also simplified because the machine automatically ejects the frozen block into a rack so that it can move straight on to producing the next block. “Our plan is to enable users to add 3D printing jobs to a virtual queue that can then be processed around the clock in shifts that run without any human intervention," says researcher Leonards, explaining what lies ahead. "In the long term, that opens up the possibility of carrying out additive manufacturing on a 24/7 operation basis."