The main reason may be lack of pressure, including during cold pressing, hot pressing, cooling stage, etc. A reasonable mold pressure should be set. It may also be due to incomplete exhaust that causes aeration. During cold pressing and material melting stage, try to discharge the air in the powder-melt gap as much as possible.
2、Surface or internal impurity contamination of the parts.
Clean mold, check powder contamination, dryer cleanliness and other possible contamination sources.
3、The color of the parts is too dark. Certain materials even degrade.
The main reason may be too high heating temperature, too long high temperature process period. Check if the set temperature and actual temperature are in a reasonable range and if the molding period of each section is reasonable.
4、There is unfused powder.
The main reason may be too low heating temperature or too short high temperature process cycle, causing the material failing to be heated and melt. Check if the set temperature and actual temperature are in a reasonable range and if the period of the molding section is reasonable.