Vacuum casting for rapid prototyping: How does it work?
Vacuum casting necessarily requires a master model. It is therefore necessary to have a 3D file (formats: IGES, .STEP, .STL, .CatPart) to launch in production a stereolithography piece that will serve as a master, or to send us an existing part that can fulfill this role. . In this case, be aware that it will be necessary to take into account the withdrawal of the cast material and thus to discuss it with our salesmen to use the most suitable material or to provide slightly larger or smaller than the desired rendering.
This additive manufacturing technique is often favored when parts are to be produced in reasonable quantities. In addition, this process makes it possible to produce a wide range of parts with varying hardnesses and properties.
Once your 3D file is received, we launch the realization of the master in Stereolithography. If you wish to have more information on this 3D printing process, please consult our page dedicated to stereolithography. Your 3D file is treated by our technicians who apply a more or less important withdrawal to the file according to the material chosen for the castings. The master model in stereolithography produces, we clean, sand and sand the room. Our prototypists apply a finish to the master model according to the specifications to be applied for the castings because the polyurethane part will be related to the appearance of its master (graining, transparency, shine, …).
Our moldmakers prepare the master to produce its imprint in a silicone mold consisting of a core of feed, vents and marking of the joint plane. Once the master model is installed in its box, the silicone is poured. When silicone is hardened, our molders open the mold. The master is gently removed to avoid damaging the silicone mold.
The casting operator in charge of the project tightly closes the mold hermetically to avoid letting the polyurethane material escape, injected into the mold. He installs it in his vacuum machine, prepares the two components of the material to mix separately and places them inside with the mold. This is closed and evacuated while mixing component A (isocyanate) and component B (polyol). The two materials are incorporated into each other under vacuum and then poured into the silicone mold by gravity.When the material leaves by all the vents created, the air is put back into the machine, and the filled mold is placed in a hot oven for several minutes until the material hardens. Once the material hardened, the casting operator goes to mold release and out the molded part.
The pilot project then goes to the deburring step of the molding. He puts the inserts or transfers (if ordered), and brings any element corresponding to your specifications.
Vacuum casting on video at Axis