The Process Of Investment Casting

Different with die casting, investment casting involves much more production processes. Based on lost-wax casting, one of the most popular metal-forming techniques, modern investment casting is also called lost-wax casting. The whole production process of investment casting includes: wax injection, wax tree assembly, dipping and shell making, baking and de-waxing, pouring, shell removing, cutting and secondary process.

Now let’s have a brief view of the investment casting process together.

Step one: Wax Injection

An injection machine is used to inject the wax into the tool cavity in order to get a wax part with desired shape. The die cavity can be simple one or multiple ones according to the production volume. The wax part is removed from the injection tool after cooling. Then they are to be inspected in terms of tolerance and then cleaned for next step.

Step two: Wax Tree Assembly

A lot of wax parts are welded to a central sprue or cluster one by one to facilitate pouring. To increase the production efficiency of investment casting, many wax parts are attached to the sprue which looks like a tree.

Step three: Dipping and Shell Making

The assembled tree is then dipped into a ceramic slurry. After draining, the sprue is then coated with a fine ceramic sand. This process is repeated several times using progressively coarser grades of ceramic material to “build” sufficient “shell” strength.

Step four: Baking and Dex-Waxing

The shell built sprue is then sent into a furnace and accept rapid heating to get de-waxed. Then the wax is melting and the perfect shell cavity is left. The shells are then fired at 1600° to 2000°. This makes a smooth interior surface, hard and strong ceramic material.

Step five: Pouring

After the cast steel is melting into liquid the hot sprue are then removed from the furnace and poured immediately. The poured shells are then set aside to cool.

Step six: Shell Removing

After cooling the sprue are sent into Vibrating machine to remove the strong ceramic material and leave the raw cast parts.

Step seven: Cutting

Parts are then cut from the sprue one by one to become an independent part.

Step eight: Secondary Process

Secondary processes includes grinding, polishing, heat treating, machining, sand blasting and etc.

Each part will accept special treatment according to different requirements.

This is the whole process of investment casting. As a professional China investment casting manufacturer, we offer steel investment casting products and other metal products. For more product services, you can refer to our list of products !