Win Joy International Co., Ltd,Investment casting (Lost-Wax)

Applications include:

• The automotive industry
• Garden tools
• Housewares
• The I.T. industry
• Sports gear
• Tableware and kitchenware
• Toys

Investment casting is also known as the lost-wax process. This process can produce intricately shaped parts with high accuracy. Additionally, metals that are hard to machine or fabricate are good candidates for this process. It can be used to make parts that cannot be produced by normal manufacturing techniques, such as; turbine blades that have complex shapes; or airplane parts that are required to withstand high temperatures.

Process Introduction

1.	The mold is produced by making a pattern out of wax.
2.	The wax pattern is dipped in refractory slurry, which coats the wax pattern and forms a skin.
3.	The pattern is dried and then dipped in refactory slurry again; this is repeated until a robust thickness of slurry is achieved.
4.	The entire pattern is placed in an oven and the wax melts away.
5.	The pattern mold is filled with the molten metal.
6.	This is then de-molded to get the cast parts from the pattern mold.
7.	The parts are then inspected.

Castings can weigh anything from a few grams to 35kg (0.1 oz to 80 lb), although the normal size ranges from 200 g to about 8 kg (7 oz to 15 lb). Normal minimum wall thickness is approximately between 1 mm and 0.5 mm (0.040-0.020 in) for alloys that can be easily cast.

For this process, the material that we are most familiar with is stainless steel. Parts made with investment castings often do not require any further machining, because of the close tolerances that can be achieved.
(Courtesy of eFunda.com)