For large volume production runs, casting and forging (with secondary CNC machining if needed) can be a more economical production method. Both process, in the simplest terms, use dies and moulds to form the required shapes of the component:
Casting Process:
Casting is a 7,000 year old process in which a liquid material is poured into a mold, which contains a hollow cavity of the desired shape, and then allowed to solidify. Some molds can be made in two halves and a core added if the cast needs to be hollow in a certain place.
The solidified part is then ejected or broken out of the mold to complete the process. Once cooled the cast part is then normally machined to remove excess material before it can be called a finished product. The cast can be turned or milled to achieve tighter tolerances and finishes.
In modern industrial casting processes the casting materials are usually metals and various alloys, Casting is most often used for manufacturing complex shapes that would be otherwise difficult or uneconomical to manufacture by other methods.
Why would you choose casting?
For general as well as large and complex components – casting is a versatile method of manufacture.
We use castings for a wide range of parts and components that are too large, complicated, intricate or otherwise unsuitable for the forging process. We can forge parts up to 10kgs but the sheer energy required to forge larger items makes casting a much more viable alternative.
The advantages of casting include:
- No real upper size limit in casting weight
- Large range of alloy choices
- Tooling is often less expensive than forge dies
- Smaller production “runs” required
- Complicated/complex parts are no problem
Forging Process:
Hot Forging or Hot Stamping is a production process which “hammers” metal between two dies to form the desired shape. Half of the die is attached to the “hammer” (upper section) and the lower half of the die is attached to the “anvil” (lower section).
A metal “blank” is placed in the lower half of the die and then “struck” with the upper die. The force of the strike forces the metal to flow in all directions, filling the die cavity and giving the parts a very strong grain structure. Excess metal is squeezed out between the die faces, and is called flash or flashing. After the forging operation, the flash is cut off in another press with a trimming die.
Cold Forging is similar in process, but is completed at room temperature so relies on force to shape the metal.
Why would you choose forging?
Forging offers uniformity of composition and structure. Forging results in recrystallisation and grain refinement as a result of the process. This strengthens the product particularly in terms of impact and shear strength.
Forged steel is generally stronger and more reliable than casting due to the fact that the grain flows of the steel are altered, conforming to the shape of the part.
The advantages of forging include:
- Generally tougher than alternatives
- Will handle impact better than castings
- The nature of forging excludes the occurrence of porosity, shrinkage, cavities and cold pour issues.
- The tight grain structure of forgings making it mechanically strong. There is less need for expensive alloys to attain high strength components
Visit our case study page to see parts we have supplied for your specific industry, or get in touch with your own enquiry if you wish to find out more.