Selecting A Casting Process

A buyer or designer of casting components should finalize the manufacturing process prior to finishing the final drawing of the part. For each process, whether it be casting, stamping, forging, powdered metal or others, alloy, shape, size, tolerance, thickness, weight and texture must be taken into account.

You might have good experience with a particular process in the past, but you must always explore new processes before going for the old one. For example, some parts can be made more price competitive with stampings using new methods of investment casting, while providing much greater flexibility in design and alloy selection.

So, allow the part function, shape, stress distribution and any special requirements such as wear, magnetism, corrosion, etc. play a major role in shaping the rough drawing. You can also take help from a casting consultant, who has the knowledge about the different processes and can contribute in terms of design and alloy selection.

You must take note of all aspects that may affect performance, cost, assembly, reliability and weight before zooming in to a particular casting process or processes. Now, you may start working with the vendors/ service providers of those casting processes who have the technical capability and know how to help you in finalizing a design for superior producibility.

Various kind of molds are used for different casting processes. Broadly, there are two categories of milds:

• Hot chamber die casting
• Cold chamber die casting
• Permanent mold gravity cast
• Permanent mold counter-gravity cast
• Semipermanent mold gravity cast
• Semipermanent mold counter-gravity cast
• Bimetal casting in all of the preceding
• Squeeze casting
• Squeeze casting with inserts
• Semisolid metal forming

• Oil bonded sand
• Clay bonded sand
• Silicate bonded sand
• Chemically set resin bonded sand mold
• Heat set resin bonded sand mold
• Thin shell mold backed with unbonded sand
• Thick shell mold cast unsupported