Vacuum casting is a multi-step process requiring thorough engineering. In general, we make a master model by stereolithgraphy and then apply whatever surface finish is needed to it. We then pour liquid silicone rubber around the master model in a casting box. Once cured, we split the silicone rubber mold and can then use it to cast up to 20 polyurethane parts.
We can make your parts soft like rubber, tough, heat resistant, clear & rigid, clear & soft, colored, textured and more. Our most popular resin is ‘UV resin’ which has similar material properties to ABS material.
Advantages of Vacuum Casting
Polyurethane vacuum casting offers a wide range of options for companies needing specific finishes, textures, materials, or other features in their prototypes. We have the ability to simulate a full range of thermoplastics and elastomers, and we can also over-mold one material over another to simulate, for example, rubber over ABS, or opaque plastic over transparent plastic. It is also possible to over-mold threaded inserts.
After casting, painting and printing is common, although polyurethane casted parts can be colored and textured in the mold. Ivy Prototype also specializes in producing high-gloss clear parts by using a CNC machined and polished acrylic master model. Polyurethane casted clear parts are very high quality. Parts made by vacuum casting at Ivy Prototype are practically indiscernible from production injection moldings.
Vacuum casting of polyurethane parts is primarily dependent upon the tolerance of the master model (see SLS tolerances), then a tolerance of +/- 0.15% is applied as a general rule. This varies depending upon weak geometry. To ensure the accuracy of Ivy Prototype’s polyurethane parts, we usually machine a Tufnol fixture for post-heat-treatment. This ensures that the part does not shrink upon heat treatment.
Low-Volume Production Applications:
• Shipping products when production tooling is delayed
• Producing high-quality products in limited quantities
• Accelerating the delivery of product revisions
• Producing customized products
• First-to-market production