1. Add additives;

When additives such as oil hydrocarbon or water are mixed into the sintered powder, the additives decompose during the sintering process and then escape along the gap of the die wall, which is beneficial to obtain completely sintered parts and improve the life of the die.

Second, hot demoulding;

When making ring parts, it is difficult to demould due to shrinkage during cooling. As shown in fig. 39 below, when the sintering is completed, while the sintered product is still cold, the forming rod 3 is taken out and the punch 2 is pushed upward, so that the sintered product can be taken out. Because this process is completely carried out in a hot state, demoulding and part molding are more convenient, and the pressing device may be miniaturized.

Thirdly, the mold is heated at high frequency;

As shown in fig. 40 below, if the high-frequency heating coil 5 is installed around the mold 1 and the temperature is kept at 200~500 degrees Celsius, the mold can be thermally expanded, and the mold can be easily demoulded.