RAPIDLY FORMING COMPLEX HOLLOW SHAPES USING LOST WAX INVESTMENT CASTING

摘要

A method for rapidly making up to 100,000 castings of a complex hollow part using the same aluminum die sets, the produced parts being fully durable and functional parts; the method combines the rapid core making and core removal capabilities of resin bonded sand or salt cores and the rapid pattern making capabilities of the lost wax investment casting technique; the process allows for modifying the interior flow characteristics of an engine head without need for changing the exterior shape of such head, leading to nimble manufacturing of engine families; the method comprises (a) making an assembly of articulate bonded sand or salt cores each spaced from one another, one core of which arcuately encompasses at least one end of another core to define at least one hidden space therebetween; (b) making an easily machined die set to receive and support the assembly of cores in spaced relation for defining a part cavity around and between the cores, including the hidden space; (c) injecting fluidized wax into the cavity with a controlled sustained pressure to fill the cavity without entrapping gases and form a pattern of the casting; (d) using the wax pattern with the assembly of cores therein to form a shell mold thereabout and to form a metal casting in the mold with the cores still in place, and (e) removing from the casting all of the particulate cores of the assembly by reversing the bond between the core particles to form a collection of particles that are freely flowable under normal gravity.