Recently, researchers at Fraunhofer IPA have developed a new process that combines 3D printing and casting. In Free Additive Casting (AFFC), the shell of the first part was printed using the FLM process, and then It is then filled with a two-component resin. This saves time, increases the stability of the part, and allows new materials to be printed.
In free-incremental casting, some shells are printed with FDM and then filled with a two-component mixture. © Fraunhofer
Additive manufacturing, also known as 3D printing, has brought a wide range of advantages to the industry. IPA expert Jonas Fischer explained: 'You enter the CAD data of an artifact, and then you can get a printed part.' In small batches, models and individual parts are manufactured faster than injection molding and are more efficient. In addition, you can also create some complex structures and integrate some functions. Of course, there are some disadvantages.
Curing takes only three minutes
The FLM (Fused Deposition) process is currently the most widely used 3D printing process. A nozzle can print a parallel line. This creates gaps and voids. Jonas Fischer added: 'This material is It is not entirely in the form of moulding. This means that the mechanical properties of the components are even worse. In addition, in the FLM process, the nozzles are applied to each layer separately. To build a large component takes a long time. The third drawback Yes, only plastics that become soft when heated (known as thermoplastics) can be used for FDM printing. Thermosetting plastics cannot be printed.
Fraunhofer researchers have now found a way to keep these shortcomings to a minimum. In order to do this, they combine the printing process with the forming process. The first step is to make the part housing through the FLM process. Experts use polyvinyl alcohol (PVA), a water-soluble synthetic polymer, as a printing material. Subsequently, the housing is automatically filled with precisely quantified polyurethane or epoxy resins. With polyurethane, it takes only three minutes. It can be done. Next, if necessary, the number of components can be increased. Once the process is complete, partially hardened, it is placed in a water bath. The 3D printed workpiece thus created has performance similar to that of the casting.
Small parts manufacturing is possible
In order to inject the filler material into the mold, IPA researchers installed a special two-component material dosing unit in the 3D printer. This means that it is possible to complete the entire process—printing the housing and filling. The printing process does not need to be interrupted. , It can be completely digitally controlled like traditional 3D printing.
IPA researchers have confirmed the feasibility of this process and created several prototypes
In addition, the program allows the use of two-component resins. The heat-resistant sleeve can be used as a building material. And, it is possible to manufacture components faster. Jonas Fischer added: 'You only need to print the housing - gravity can be done The rest of the work. ' Finally, when the material is completely filled, the stability of these elements will be greatly improved, so there will be no pores or pores.
This new method is suitable for a variety of applications and industries. Fischer explained: 'For example, it can be used for electrical isolation components such as sockets. Foams and cushions, such as those required for safety, also apply to this process In principle, the free additive casting process is preferred when large and complex components are needed in small quantities. In addition, it also contributes to weight reduction.