A: the forming method-can be selected from two basic material types. Hot working tool steel capable of withstanding relatively high temperatures during die casting, forging and extrusion. B) cold working tool steel, which is used for blanking and shearing, cold forming, cold extrusion, cold forging and powder pressure forming. Plastics-some plastics produce corrosive by-products, such as PVC plastics. Corrosion can also occur due to factors such as condensation, corrosive gases, acids, cooling/heating, water or storage conditions caused by prolonged downtime. In these cases, the use of stainless steel is recommended. Die size-large size dies are often made of pre-hardened steel. Integral hardened steel is often used in small-size dies. Die usage-die usage (& GT. Million) should be made of a high hardness steel with a hardness of 48-65hrc. For medium to long service (100,000 to million) moulds use pre-hardened steel with a hardness of 30-45 HRC. Soft steel with hardness of 160-250hb should be used for short time use (& LT; 100000 times) . Surface roughness-many plastic mold makers are interested in good Surface roughness. When adding sulfur to improve metal cutting performance, the surface quality will decrease. Steel with high sulphur content also becomes more brittle.