There are many ways for starting of the casting process may be expressed, but the most common way of starting this procedure to supply us your drawings and detailed specification of your product. Once we get these drawings we get in touch with customers design engineer and build an aluminium die with internal cavities that will produce a wax sample by injecting wax into the die. We send these wax patterns to customer and after approval of wax patterns we make sample casting. The wax patterns are attached to an assembly made from wax (called cluster/tree) that allows molten metal to enter, that produces a sound metal component.
The cluster is rinsed in a pattern wash/etching solution. The cluster is then dipped into controlled ceramic slurry. The cluster is drained and coated with a ceramic media that begins with a fine powder like ubstance on the first coat. Subsequent coats are put on the cluster called secondary or backup coats. The secondary/back up coating process is repeated as necessary until the shell is strong enough to hold molten metal. After the ceramic dries, the wax is removed (called De-Waxing process). The wax will be recycled for use in future wax pattern assembly production. These ceramic shells provide an accurate copy of the wax patterns that will be used for producing metal components.
The ceramic shell moulds are fired in ovens to burn out last traces of pattern material and in order to achieve maximum strength, then removed and placed on sand beds. By that time based on the specifications provided by the customer, metal is melted in the furnaces using certified material and then verified using spectrometer to insure that the metal chemistry meets the specifications. This ceramic shell is filled with the molten metal.
After the molten has cooled, the shell material is removed from the casting cluster using vibratory or shot blast methods.The castings are removed from the cluster by cutting gates. Remaining parts of gates are then removed by grinding and then using shot or sand blasting, finished components are achieved. Post Processing
» Heat Treatment
» Blasting (Sand and Shot)
» Knock Out
» Hand Buffing
» Corrosion-resistant Coatings
» Electro Plating
» Black Oxide
Advatages of Investment Casting
» Allows very rapid prototype development
» Allows greater design freedom for very simple to highly complex parts
» Can utilize a wide variety of alloys
» Yields lighter, stronger metal parts with superior finishes
» Provides superior repeatability
» Reduces labor, tooling and machining cost
» Close Dimensional Tolerances
» Sales appeal is enhanced by improved performance
» 85% or more of the final shape is available in the investment casting
» Physical properties remains same in each dimensions
» Design changes at costs far less than those of other techniques
» Requires little or no draft in tooling