Shenzhen Alu Rapid Prototype Precision Co., Ltd.

Metal casting is a manufacturing process used to create complex metal parts by pouring molten metal into a mold cavity, allowing it to cool and solidify into the desired shape. It's one of the oldest and most versatile methods, applicable to metals like iron, aluminum, steel, and bronze. The process can vary by technique (e.g., sand casting, die casting, investment casting), but the core steps are similar. Below, I'll outline the general steps for the most common method, sand casting, based on established industrial practices.

Step-by-Step Process of Sand Casting

1.Patternmaking: A reusable pattern (often made of wood, plastic, or metal) is created in the exact shape of the final part, slightly oversized to account for shrinkage. This pattern serves as a template for the mold.

2.Mold Creation: The pattern is placed in a flask (a box-like frame) and packed with sand mixed with a binder (like clay or resin) to form the mold cavity. For hollow parts, cores (sand shapes) are inserted to create internal voids. The mold is typically split into two halves (cope and drag) for easy removal.

3.Melting the Metal: The chosen metal is heated in a furnace (e.g., induction or cupola furnace) until it becomes molten, typically reaching temperatures of 1,200–1,500°C (2,200–2,700°F) depending on the alloy. Impurities are skimmed off to ensure quality.

4.Pouring: The molten metal is ladled or poured through a sprue (a channel) into the mold cavity, filling it completely. Risers (extra reservoirs) may be added to compensate for shrinkage as the metal cools.

5.Cooling and Solidification: The mold is allowed to cool naturally or with controlled cooling to let the metal solidify. This can take minutes to hours, depending on the part size.

6.Shakeout and Removal: Once cooled, the mold is broken apart (shaken out), and the solidified casting is removed. Any cores are extracted.

7.Cleaning and Finishing: The casting is cleaned of sand, gates, risers, and flash (excess metal) using tools like grinders, shot blasters, or chemical baths. Surface treatments (e.g., heat treatment, machining, or coating) may follow for strength and precision.

8.Inspection: The final part is checked for defects like porosity, cracks, or dimensional accuracy using visual, X-ray, or ultrasonic methods.

Variations in Metal Casting

Die Casting: Uses a reusable metal mold (die) under high pressure for high-volume production of precise parts, like engine blocks. No pattern is needed, but it's limited to non-ferrous metals.

Investment Casting: Involves creating a wax pattern coated in ceramic, melting out the wax, and pouring metal—ideal for intricate shapes like turbine blades.

Centrifugal Casting: Rotates the mold to force metal outward, used for pipes and cylinders.