What is investment cast/casting?

I know Ruger rifle receivers are made this way but dunno what the process is.

Thanks for info.

In very rough terms:

The part you wish to make is made from a wax-like substance that is invested in a plaster slurry and further invested in some other mold material. The wax part is then melted out and the mold cured.

After the curing the metal is melted and poured or injected into the cavity that the wax left.

Much more to it than that but that is a rough idea of the process.

mc

Also known as the "lost wax process"

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NRA Life member

It is called investment because the process was invented by the Jewellers trade. Almost all jewelery is investment cast. I great many titanium parts are also investment cast. I have a friend how works for GE as a jet engineer engineer.

Kent

The mold material is usually a ceramic of some sort and it is broken after the part is cast to release the item. We had a foundry near here that did a lot of items for the aerospace industry and I have accompanied way too many cub scouts through the place. They do fascinating things with it.

Chic Worthing

The latest twist on "investment casting" is the "lost foam" process. General Motors (as well as many other manufacturers of complex aluminum castings) Is looking to this method to cast complex cylinder heads and engine blocks. I work @ a "lost foam" foundry as a pipefitter. (GM Powertrain Massena NY) The process is similar in some respects to the "lost wax" process. Cylinder heads and blocks are made in multiple layers from styrofoam. These foam "patterns" are aged in an oven for dimensional consistancy, coated with a ceramic slurry and dried in an oven. They are then placed in a metal box and loose sand is compacted (by vibration) around them. When the molten aluminum is poured in, the foam vaporizes and is burned away. When the "cluster" is removed, compressed air is force through the sand, "fluidizing" it, allowing the cluster to be removed by a robot. The robot then lifts the cluster, turning it allowing the loose sand to flow out of the casting. This process eliminates a lot of machining, (for oil galleys etc.)and may someday be the method of choice for casting most complex castings.

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Life is more exitin' when yer stickin' suppositories inta a wildcats behind!

[This message has been edited by wildcat junkie (edited 02-02-2002).]

[This message has been edited by wildcat junkie (edited 02-02-2002).]

Thanks for info.

Those of you who have ever looked at the engine in a Saturn will notice the "styrofoam" surface texture on the cylinder head. It may work just fine, but it sure looks cheap.