Adding support for 3D printed parts is a part of additive manufacturing design. The support structure functions to support the part, prevent deformation of the part, and the like. Whether it is powder bed selective laser melting metal 3D printing technology or resin light curing 3D printing technology such as SLA/DLP, it is necessary to add support in printing. Although professional software can help designers to add support structures reasonably, reducing the time to remove support after printing is completed, designers with additive manufacturing experience will also reduce the support structure by properly adjusting the placement of parts. But it is undeniable that even the presence of a small number of support structures will increase the cost of printing and increase the post-processing time of 3D printed parts.

The Fraunhofer Institute (Fraunhofer ILT) and Rapid Shape have developed a 3D printing technology called "TwoCure", which allows plastic parts to be printed without the need for additional support structures, which is expected to further improve the efficiency of 3D printing of resins.

"cold" and "hot" combined to achieve unsupported resin 3D printing

According to the Fraunhofer Institute, "TwoCure" is a process for forming parts by interaction of light and cold. This process is very similar to the widely used photocurable 3D printing technology, and the photosensitive resin material is cured layer by layer by lithographic exposure.

The 3D printing device based on "TwoCure" technology is similar to other 3D printing systems manufactured by Rapid Shape. The LED lighting unit illuminates the resin material according to the geometry of the part, just like using a projector, the image is projected into the resin pool, the polymer Harden in the illuminated area. The resin in other areas initially remains in a liquid state.

"TwoCure" technology 3D printed resin double link without the need to add a print support structure Image Source: Fraunhofer ILT & Rapid Shape GmbH.

The difference is that during the "TwoCure" 3D printing process, the printed parts are cured under the illumination of warm light. At the same time, the cooling space causes the layer-by-layer created thermosetting component to freeze into a block together with the resin, just like a wax. The user can then liquefy it at room temperature to allow such material to be discharged from the support structure, and the 3D printed part can be simply cleaned and post cured. The technique was named "TwoCure" because of two cures during the printing process.

Liquefaction melting causes the frozen-cure "support portion" to be discharged. Source: Fraunhofer ILT & Rapid Shape GmbH.

“TwoCure” 3D printing technology is part of the research results of the German Federal Ministry of Economics and Energy-sponsored Small and Medium Enterprise (ZIM) project innovation program. Prior to the birth of TwoCure technology, due to the fragile structure of the resin material, if the support structure was not printed, it would collapse. Andreas Geitner, technical director at Rapid Shape, said adding support structures can be a problem for users to apply 3D printing because they need extra preparation for CAD models and more time for post-processing of parts. The "TwoCure" 3D printing technology not only does not require the addition of a support structure when printing, but the technology is more efficient.

Image source: Fraunhofer ILT & Rapid Shape GmbH.

With TwoCure technology, printed parts are not in contact with the workbench, but are “floating” throughout the print area. According to Holger Leonards, project manager at Fraunhofer, this printing method makes the overall construction area more efficient and can create more parts per 3D printing.

The materials and photochemical processes in the “TwoCure” 3D printing technology were developed by Fraunhofer, which is responsible for the formation of 3D printing systems based on materials and processes. Currently, the first prototype has been manufactured and will soon be ready for mass production. The device has passed the application test of the jewelry manufacturing model. This also means that if jewelry manufacturers use "TwoCure" 3D printing technology to make models for jewelry casting, there is no need to add support structures and no effort to remove these support structures.

(Editor)