A novel curing process for 3D printing plastic components without support structures has been developed by Fraunhofer Institute for Laser Technology ILT and Rapid Shape, a 3D printing machine maker based in Heimsheim, Germany.
The first TwoCure components and information about the process will be presented by Fraunhofer ILT at Formnext from 14 to 17 November in Frankfurt am Main.
The new process, along with needing no support structures, is more efficient and productive than conventional 3D printing techniques for plastic components. A liquid resin is still used, and an image projected into the resin bath to harden the polymer. Similar to other systems built by Rapid Shape, an LED light unit illuminates the liquid resin. Unlike traditional processes, however, the photochemical curing is then cooled to set the component.
Supports were used up until now because the plastic structures, which are often delicate, would otherwise collapse. ‘Users dislike these process-related supports because additional CAD preparation and time-consuming follow-up work delay the production process,’ said Andreas Geitner, technical director at Rapid Shape.
The process developed in cooperation between research and industry not only does without supports, it also enables components to be positioned in the entire build volume without being connected to the platform.
‘The material is applied warm and then irreversibly cured by light,’ explained Holger Leonards, a project manager at Fraunhofer ILT. ‘At the same time the cooled installation space ensures that the thermoset component being created layer by layer freezes to form a block with the resin that has solidified like wax.’
The user can subsequently liquefy this at room temperature, so that the support material drains off: what remains are the 3D printed components that just need to be briefly cleaned and post-cured. The aim in future is for these steps to be automated in a process chain too.
The material and photochemical process were developed by Fraunhofer ILT, while the procedure and systems technology were created by Rapid Shape.
The first prototype has already been built and should soon be ready for series production. This new kind of polymer 3D printing was successfully tested with models for the jewellery industry. These models are used to create jewellery rings, for example.