The design and manufacture of blow molds with fast cycle times and long life is required for the development of the blow molding industry.
    The factors that determine the efficiency of the mold are: 1. Material 2. Cooling  3. Venting
Material
    The material from which the mold is made must have high thermal conductivity and sufficient cutting edge strength. Currently, aluminum 70/75 is a high-grade alloy for most molds. Due to the good machinability of the metal, the cavity is usually machine-cut. Copper alloy molds also have high heat transfer properties and good corrosion resistance. However, its cost is high, the price is expensive, and because its proportion is three times that of aluminum, it may be more serious in the molding machinery. Steel alloy molds are easy to repair by welding or mosaic.

The thermal conductivity of cast aluminum molds is worse than that of aluminum molds. The blanking port of the cavity usually requires beryllium copper alloy or stainless steel inlay, because the strength and hardness of the cast aluminum do not meet the requirements of the cutting edge.

Cooling

 Cooling is a challenging and important part of mold design. Drilled cooling lines are installed where cooling is most needed. For better production control, most molds are designed with several separate cooling zones. The neck and bottom need to discharge the most heat, thus it requiring the most efficient cooling.
Venting
    In order to allow the gas to escape quickly during the blow molding of the part, the mold must be vented. The most common and economical method of venting is surface venting. Deep blasting or texturing of the cavity also help to vent. Another important reason for venting (for those parts where plastic must be blown into tightly narrow cells) is to show details.