Cold forging is a high-precision shaping technology. It is a closed mold, so the tolerance for the amount of material supply shall be 10, and the average error shall be +/-1 gram. When it is flattened, the roundness error used by the external diameter shall be within 30-40 strips. If the external diameter is too big, work-pieces cannot be placed in. If the external diameter is too small, when it put into the mold to forge, work-pieces’ size will be different, so it cannot meet our requirements. Therefore, we recommend using the automatic cutting and flattening machine.