Process
The binder jetting technology was first developed at the Massachusetts Institute of Technology in 1993 and is generally known as the "Powder bed and inkjet head 3D printing". As usual in the additive manufacturing processes, the part to be printed is built up from many thin cross sections of the 3D model. An inkjet print head moves across a bed of powder, simultaneously putting down a liquid binding material. After that, a thin layer of powder is extended across the completed section and the process is repeated several times with each layer adhering to the last.
In 2017, voxeljet introduced its High Speed Sintering (HSS) technology. HSS is a powder-based 3D printing process that produces functional plastic parts from materials such as polyamide 12 (PA12) or thermoplastic polyurethane (TPU). The technology employs an ink jetting process that starts by spreading a thin layer of polymer powder onto a build platform. An inkjet printhead then selectively jets an infrared-absorbing ink into the areas of the build where the part is to be produced. An infrared lamp then passes over the layer, fusing the printed areas while the unprinted powder remains loose and acts as a support material during the build. This process is repeated layer by layer until the entire build volume is filled. After cooling, the parts can be unpacked.
In 2019, voxeljet announced a joint project with the Spanish foundry equipment manufacturer LORAMENDI S COOP. The project, called "Industrialization of Core Printing (ICP)", aimed to serial-additive manufacture water jacket cores at the BMW light metal foundry in Landshut, Germany. The project was completed in 2023.
In 2021, voxeljet, together with GE Renewable Energy and the Fraunhofer IGZV Institute, announced a joint project that aligns with the U.S. strategy for clean power generation. The project involves the development of a new 3D printer that prints sand molds for the casting of parts for offshore wind turbines and water turbines. In 2023, the project received funding from the U.S. Department of Energy.
Application area
The voxeljet process is particularly well-suited for the production of molds or models for metal casting applications in small series, such as prototypes, individual parts, props, investment casting or sand casting. In addition, the method is used for design samples, art and architecture components as well as in the aviation and aerospace industry, automotive industry, research and medicine and in the film and entertainment industry. In High Speed Sintering, functional parts can directly be 3D printed.
Materials
voxeljet offers two plastic materials based on PMMA particles bound by different resins. The Polypor B binder, available as a voxeljet service and for system customers in Europe, is ideal for parts that are true to detail and which require a high degree of edge sharpness, resolution and green compact strength. The Polypor C binder, on the other hand, lends itself to simplified burn-out processes in investment casting and for architectural models.
The sand types are selected individually for each order depending on the geometry and application purpose. voxeljet uses different sands with different granulations. The grain size that is used will decide the surface finish of the cast result. The most commonly used sand is made of quartz and is available in the granulations 0.14 mm, 0.19 mm and 0.25 mm. Also offered is the more temperature-resistant kerphalite sand, which is suited for especially complex geometries and internal cores for steel casting.
In High Speed Sintering, functional parts can be manufactured in PA12, PP, TPU, PEBA and EVA based polymers.
