About Metal Casting : The Explain of Process

Aug. 10, 2021

cast iron flange

cast iron flange

Metal casting is a metal processing process involving liquid metal and molds, which has existed for thousands of years. As a supplier of metal castings, we will explain the casting process of metal castings to you.


What is Metal Casting?

Metal casting is a modern process with ancient roots. Metal casting is a manufacturing/fabrication process that involves pouring molten liquid metal into a mold. The inside of the mold is designed with a negative impression of the part being made, so when the molten metal cools and solidifies within the mold, it takes the shape of the final part. The finished part can then be removed from the mold.

Metal casting is arguably the earliest and most influential industrial process in history. It's used to make many of the metal objects used in our daily lives: automotive parts, train wheels, lamp posts, school bus pedals, and much more.

Plus, metal casting foundries rely on metal recycling as a cost-efficient source of raw material, significantly reducing wasted scrap metal that might end up in landfills.


The Metal Casting Process

1.Pattern-making: A pattern is a replica of the exterior of the casting. Patternmaking is incredibly important for industrial part-making, where precise calculations are needed to make pieces fit and work together. Patterns can be either permanent or expendable and can be made of materials like plaster, wood, and plastic.


2.Core-making: If casting is hollow,  it may be necessary to design a core. An additional piece of sand or metal,  called a core, shapes the internal form to make it hollow. Cores are typically strong yet collapsible so they can be easily removed from the finished casting. (For example, a cylindrical core within a larger cylindrical mold will produce a tube-shaped cast part.)


3.Mold making: The practice of fabricating molds is known as mold making and is a specialist discipline. Molding is a multistep process that will form a cast around the pattern using molding sand. Molds are made in different ways depending on the process. For example, permanent metal molds can be made using a CNC machine, while sand molds are made by applying a sand mixture to the exterior of a pattern.


4.Filling the mold: Heat the metal until it melts, then pour or force it into the mold. For example, in gravity casting, the molten material is poured down into the cavity; in high-pressure die casting, it is forced into the cavity under high pressure, requiring high clamping force to keep the mold safe.


5.Take out the parts: After the casting has cooled and solidified, it can be taken out from the mold. For sand casting and other processes, it is necessary to destroy the mold if the internal casting is to be removed; for a permanent mold that can be used again, the two halves of the metal mold can be pulled apart to take out the internal casting.


6.Final trimming: Cast metal parts may need trimming before they are ready for use-remove the cast metal object from the mold and then trim it. During the trimming process, any molding material on the object will be removed, and rough edges will be removed.


The relationship between the core and the mold in the metal casting process can be simply understood as: the footprints left on the beach when you walk to the sea on the beach. Your foot will be the core, and the mark left in the sand is the mold of your foot. If you have any questions or need metal castings, please feel free to contact us.