Vat Photo Polymerization

The Admaflex technology originates from Vat Photo Polymerization (VPP), currently the most reliable and precise additive manufacturing technique. Vat Photo Polymerization, also called Lithography based Additive Manufacturing, is a way of 3D printing layer-by-layer, using photosensitive liquid polymers cured through light. During the printing process, the layers are added and cured with help of UV-photo curing. After the printing, the parts are cleaned and undergo the debinding and sintering steps. By sintering, the material consolidates to obtain the final properties. 

Stereolithography and Digital Light Processing

Where Stereolithography (SLA) uses ultraviolet light to create laser spot size resolution, the Admaflex technology applies a derivative of it; Digital Light Processing (DLP). DLP can be seen as an updated and more efficient version of SLA, as it uses a projector screen instead of a laser, to flash an image across the full platform per layer. Therefore, the primairy resolution of the Admaflex technology is expressed through pixel size, as projections are set-up out of square pixels. The final print and part resolution can exceed the optical pixel resolution by optimizing intensity and illumination strategies. Features of better than half of the pixel size have proven to be obtainable. 3D printing often requires the use of supporting structures. With Admaflex technology, larger build angles are possible as shown in our design guidelines and therefore less supports are needed.

Build sizes and resolutions are increasing

DLP systems continue to develop, mainly driven by demand for high resolution projection systems. Currently our biggest projection sizes are 260x220 mm with approx. 80 um primary pixel resolution. Further expansion of build sizes is expected.

Bottom-up printing

The Admaflex technology applies the “bottom-up” printing principle meaning that the building platform moves down into the slurry, curing each layer with help of a light source from below, and moves up again. This system allows to work with very small amounts of slurry/feedstock, meaning that with less then 15 cc of slurry material a print job can be started. The required slurry volume is the volume of the part plus a few percent extra for the cleaning of the part. The bottom-up printing principle with Admaflex technology allows excellent visibility of the printing process and printed parts. Vision-based In-Process Monitoring is therewith easily implemented and available for all Admatec printers.

Tapecasting

We developed an innovative way to transport our slurry, by using a foil roll during the printing process. This tape casting process distributes an even layer of slurry onto the foil and moves it under the building platform. When the Z-stage moves down, the start plate is pressed into slurry and the UV light cures the next layer in a matter of seconds, or less. The slurry which is not used in the product is collected by a wiper and pumped back into the initial reservoir, minimizing material waste to almost none.

Patented foil system

As there is no direct contact between the slurry and the glass plate, there is no wear of the glass plate. Every layer is added using a fresh piece of foil, so there is no influence from previous layers or scratches. After a layer has been cured and the Z-stage moves up, the foil ensures a very low peel-off force. As the tension of the foil can be controlled, it can be released very gently from the cured layer, avoiding damaging a layer or part. The excellent visability of the total process, allows to use multiple camera systems to monitor the process and give feedback to the printing control system. The printer stores full logfiles of each layer and each part for quality assurance and registration. 

Reliability and precision

Printing through Admaflex technology enables you to produce complex geometries with tight dimensional tolerances, fine details and smooth surfaces. The advantages of Admaflex 3D printing technology in combination with the superior material qualities of ceramics and metals, opens up a span of applicability for high-tech industries with the potential to change the industry of the future.

Efficiency and flexibility

Using a UV DLP projector screen which illuminates the full building platform in a matter of seconds (or less) is much faster compared with a UV laser spot, which needs much more time writing the image with a small beam. In addition, DLP is more cost-effective than other technology and the used wavelength can be adjusted easily to the need of the customer. The Admaflex technology applies bottom-up printing taking up less slurry compared to top-down configuration.

The need for post processing is a benefit

The quality of the parts after debinding and sintering are considerably higher than other additive manufacturing techniques, because the sintering allows to achieve and control the level of density required for the final product/application. For example, parts printed in alumina can achieve nearly 100% density while parts printed in silica or bone-like ceramics can have a higher porosity if that is required for the applications, such as shells and cores for investment casting and bioceramics for implants. Also, the quality of the printed parts is comparatively higher to other additive manufacturing techniques (such as SLM) so that no labor intensive post-processing like grinding, lapping or polishing is required. Still post-processing could be done upon specific requirements as an added value, for example the polishing of aesthetical parts. This is beneficial, since existing powders and familiar post-processing techniques from traditional manufacturing methods can be applied. 

Applying Admaflex additive manufacturing technology to produce technical ceramics is the best commercial available technology for advanced ceramics 3D printing as it obtains products with fine features, high accuracy and smooth surfaces. End-use parts of high dense ceramic and metal can be produced with excellent material properties, comparable with traditional shaping techniques. This technology enables the production of high-quality products for high-demanding markets, such as medical, aviation, investment casting, scientific research and many others.

The efficient use of printing material make Admaflex technology ideal for cost-efficient production and developing own (precious) materials. The high speed of the printing process (compared with traditional VAT and laser printing) and the possibility to scale up to bigger build platforms, make Admaflex technology an excellent choice for scaling up to high production volumes. As a technology development never stops, we are always investigating further possible improvements and new opportunities, so check out our latest news and developments if you’re curious to learn more.