Introduction
Detailed Explanation of Raw Materials and Supply Methods for Each Process
Casting
All casting methods share the commonality of using molten metal (melt) as the raw material. This melt is stored in a holding furnace and then fed into the mold using various methods.
- Sand Casting & Shell Casting: Manual or automated pouring is often performed using a ladle.
- Low-Pressure Casting: The molten metal is fed upward or downward into the mold using air pressure.
- High-Pressure Die Casting: The molten metal is transferred from the holding furnace to a press chamber (shooting barrel) where it is ejected at high speed.
Sheet/Tube Forming
This process uses solid metal coils, sheets, or tubes. These standardized sizes are fed into a press, bending machine, or tube bending machine, where they are formed into their final shape through die pressure.
Aluminum Extrusion
Aluminum extrusion uses a preheated, solid aluminum billet. Under high temperature and pressure, the machine squeezes the solid aluminum billet through a custom-shaped die, like squeezing toothpaste, to form a continuous, long profile.
Forging
Forging uses solid metal bar or wire billet. Depending on the process temperature (hot forging, warm forging, or cold forging), the billet is hammered or squeezed under intense pressure at varying temperatures, deforming it into a high-strength part.
Metal Injection Molding/Powder Metallurgy (MIM/PM)
This process uses fine metal powder as its base material. In the MIM process, metal powder is first mixed with a polymer binder to create a “feedstock” similar to plastic pellets, which is then injection molded. Traditional powder metallurgy (PM) involves mixing metal powder with a lubricant and then directly pressing and forming it in a mold.
CNC Machining
CNC machining offers the most flexibility in raw materials. These can be solid metal bars or sheets purchased directly from the factory, or preformed blanks from other processes (such as casting, forging, and extrusion). CNC machining performs precision secondary operations such as milling, drilling, and tapping on these raw materials to achieve the required final dimensional accuracy.
Conclusion
Based on the raw material form, metalworking can be divided into three categories: “casting” using liquid metal, “forging/forming” using solid metal for plastic deformation, and “powder metallurgy” using metal powder. CNC machining plays the role of connecting these various processes and completing the final stage of precision machining. Understanding which raw material form your product is best suited to start with is fundamental to planning your overall manufacturing process and costs.

