Investment Casting Tooling
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Investment casting tooling, also called wax pattern tooling, is necessary for all investment castings. The tooling is what creates the mold in the sand that will eventually give the part its shape. The tooling is made from high grade aluminum alloys, and designed to allow the flow of molten wax under extreme pressure, in order to allow it to solidify into the wax pattern which is used to form the ceramic mold during the investing process. When creating tooling out of aluminum, it is common to see tooling on both sides of the aluminum, one side is the cope and the other is the drag. This double sided tooling is known as a matchplate and is used in automated machines to produce thousands of molds a day. Aluminum is the material of choice for matchplates because it is fairly easy to machine while providing the necessary durability to withstand repeated use.
Unlike sand casting, investment casting tooling replicates the final casting in reverse, due to the fact that we cut “cavities” in which the wax flows to form our patterns. This tooling is often designed to be “collapsible”, in other words, it must be able to be taken apart to remove the solid wax patterns when they have cooled.
Another critical element of the tooling design is that the tooling must be constructed so that the wax patterns produced are larger than the final casting dimensions. This is due to the fact that metal shrinks during its solidification, so our engineers must calculate an expected shrinkage rate for every dimension in the tool, and apply those expected shrinkage rates when cutting the tooling. In the pattern tooling, any internal features can be produced, however if the various metal components of the tooling cannot be removed from the wax after solidification has taken place, a suitable method of coring will need to be utilized to form internal features. Finally, the tooling can consist of simple single cavity varieties, or complex multi-cavity tools with automatic ejectors for higher volume jobs.
Creating foundry toolings is more of an art than it is a skill, it takes years of experience to learn the tricks of the trade. In recent years the introduction of new tooling material and different techniques to produce the tooling has changed the art of pattern making. JC Casting has a wide range of wax presses to accommodate most every tool design and size, as well as for all ranges of jobs from small volumes to large.
We can also provide CNC machining services.