Injection Molding & 3D Printing Combine to Make ‘Impossible’ Parts
Stereolithography cavity inserts can be injected with thermoplastic, then removed from the mold and dissolved away to leave a complex-shaped part.
Could this be the ultimate crossover between injection molding and 3D printing? At next month’s Rapid + TCT show and conference in Detroit, AddiFab of Denmark (addifab.com), Mitsubishi Chemical America, and Alba Enterprises will collaborate to provide an answer. AddiFab (U.S. office in Palo Alto, Calif.) supplies 3D printing machines and materials that use a stereolithography technique to light-cure liquid resins. Its Freeform Injection Molding (FIM) process (freeforminjectionmolding.com) involves building a cavity insert in the form of a short cylinder with a hollow cavity inside and a sprue hole at one end. This insert is subsequently rinsed to remove all uncured resin from the cavity inside, and then is post-cured to develop full properties, including high heat resistance (high enough to permit molding PEEK). At the Mitsubishi booth (2105) at the show, the insert will be placed in a mold base in a Babyplast tabletop injection machine (sold in the U.S. by Alba) and injected with Mitsubishi’s high-performance TPE. Then the insert will be removed from the mold and dissolved in an alkaline water solution, leaving a thermoplastic part whose complex shape would be “impossible” to injection mold by conventional methods.
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