New Multimaterial SLA 3D Printing Method: Skipping the Liquid Bath with Aerosol Jet Printing

While SLA 3D printing is extremely popular among many different types of users today, there are drawbacks in post processing, as users are forced to take a more laborious step following the layer-by-layer method in using a liquid bath. While many are glad to continue this way, and are used to conforming to this traditional process, it is also limiting. German researchers have created a hybrid form of SLA 3D printing to streamline and expand production, which they explain in their recently published work, ‘Multimaterial bathless stereolithography using aerosol jet printing and UV laser based polymerization.’

Iterative layer-by-layer process of hybrid stereolithography

Rather than continuing with the normal bath used in SLA 3D printing, the authors have created a spray coating device instead:

“The AJS is able to process inks in the range between 10 and 1000 mPa s,” state the researchers. “Therefore, UV curable materials with greater viscosity compared to inkjet based raw materials can be used to establish a material layer and open the field for a wide range of materials.

“The modified system allows the mixing of two different materials through the addition of a second spray generator. This enables the printing of two pure materials as well as a theoretically continuous gradient.”

The AJS system is made up of:

• Two atomizers
• Two virtual impactors
• Mixing module
• Nozzle

Compared with a conventional inkjet system, the AJS is superior in processing liquids, relying on two atomizers. These components competently control the flow of materials, ultimately mixing the two (with one flow coming from each atomizer). The system also ensures good performance in printing as the combining of flows is exact, and with no backflow present. As the authors explain, push flow must be the same in both mixing areas, with the flow then accelerated by the nitrogen.

The ‘working distance’ created manages proper deposition and eliminates any chance for clogging. In conclusion, the researchers stated the following regarding potential for this process:

“This enables the freeform fabrication of parts with undercuts, as demonstrated in a 3D printed part. Due to two available atomizers in the AJS device, the materials are mixed on the fly for desired material compositions. Hence, a transition from one pure material to the other is demonstrated with three intermediate material compositions. This opens the possibility to fabricate parts with varying material properties. This is a promising technique to establish multimaterial printing for the stereolithography and widens the range for possible applications.”

Hearing aid component, CAD file (left), printed by hybrid stereolithography (right).

The SLA 3D printer is known as the original 3D printing system, created in the 80s; yet while it may be one of the oldest methods of 3D printing, it is still one of the frontrunners behind innovations today. Researchers and manufacturers continue to forge ahead with this technology, reformulating resins, improving multi-material processes, and creating useful products like ceramic molds. What do you think of this latest technology news? Let us know your thoughts! Join the discussion of this and other 3D printing topics at 3DPrintBoard.com.

Modules of the hybrid stereolithography (deposition, polymerization, and stages).