Plastic molds are tools that are matched with plastic molding machines in the plastic processing industry to give plastic products a complete configuration and accurate dimensions. According to different molding methods, different types of molds can be divided.

1. Injection mold

   
   

   It is a molding mold that is widely used in the production of thermoplastic products. The corresponding processing equipment for injection molds is an injection molding machine. Plastic is first heated and melted in the heating barrel at the bottom of the injection machine. Then, under the push of the screw or plunger of the injection machine, it enters the mold cavity through the nozzle of the injection machine and the gating system of the mold. The plastic cools and hardens to form a product, and the product is ejected.

   
   Its structure usually consists of molding parts, gating system, guiding parts, ejection mechanism, temperature regulating system, exhaust system, supporting parts and other parts. It is manufactured using plastic mold steel. Injection molding processing methods are usually only applicable to the production of thermoplastic products. Plastic products produced by injection molding technology are very extensive. From daily necessities to various complex electrical appliances, automotive parts, etc., are all molded by injection molds. It is a processing method widely used in the production of plastic products.

2. Blow molding mold

   
   

   A kind of mold used to mold hollow products of plastic containers (such as beverage bottles, daily chemical products and other packaging containers). The forms of blow molding mainly include extrusion blow molding hollow molding and injection molding according to process principles. The forms mainly include extrusion blow molding hollow molding, injection blow molding hollow molding, injection stretch blow molding hollow molding (commonly known as injection stretch blow molding), multi-layer blow molding hollow molding, sheet blow molding hollow molding, etc.

   
   The equipment corresponding to hollow product blow molding is usually called a plastic blow molding machine. Blow molding is only applicable to the production of products made of thermoplastic varieties. The structure of blow molding molds is relatively simple, and most of the materials used are made of carbon.

3. Extrusion mold

   
   

   A kind of mold used to mold continuous-shaped plastic products. It is also called an extrusion molding head. It is widely used in the processing of pipes, rods, monofilaments, sheets, films, wire and cable sheaths, profiles, etc.

   
   The corresponding production equipment is a plastic extruder. The principle is that solid plastic is melted and plasticized under the conditions of heating and screw rotation and pressurization of the extruder. Through a specific shaped die, a continuous plastic product with the same cross-section as the die is made. Its manufacturing materials mainly include carbon structural steel, alloy tools, etc. Some extrusion molds will also be inlaid with wear-resistant materials such as diamond on parts that need wear resistance.
   The extrusion process is usually only applicable to the production of thermoplastic products. It is obviously different from injection molds and compression molds in structure.

4. Blister mold

   
   

   A kind of mold that uses plastic sheets and sheets as raw materials to mold some relatively simple plastic products. The principle is to use vacuum forming methods or compressed air forming methods to make the plastic sheets and sheets fixed on the concave mold or convex mold deformed under the condition of being heated and softened and attached to the mold cavity to obtain the required molded product. It is mainly used in the production of some packaging products for daily necessities, food, and toys.

   
   Due to the low pressure during molding of blister molds, the mold materials are mostly made of cast aluminum or non-metallic materials, and the structure is relatively simple.

5. Compression mold

   
   

   It includes two types of mold structures: compression molding and transfer molding. They are mainly a kind of mold used to mold thermosetting plastics. The corresponding equipment is a pressure molding machine.

   
   According to the characteristics of plastic, the compression molding method heats the mold to the molding temperature (generally 103°-108°), then puts the measured compression molding powder into the mold cavity and the feeding chamber, closes the mold, and the plastic becomes softened and viscous under the action of high heat and high pressure. After a certain period of time, it is cured and shaped into the required product shape.
   The difference between transfer molding and compression molding is that there is no separate feeding chamber. The mold is closed first before molding. The plastic is preheated to a viscous state in the feeding chamber, and is adjusted and squeezed into the mold cavity under pressure to harden and form.
   Compression molds are mainly composed of cavities, feeding chambers, guiding mechanisms, ejection parts, heating systems, etc. Transfer molds are widely used in encapsulating electrical components. The materials used to manufacture compression molds are basically the same as those for injection molds.

6. High-expansion polystyrene molding mold

   
   

   It is a kind of mold that uses expandable polystyrene (bead-like material composed of polystyrene and foaming agent) as raw material to mold various required shapes of foam plastic packaging materials.

   
   Its principle is that expandable polystyrene can be molded by steam in the mold, including two types: simple manual operation molds and hydraulic press through-type foam plastic molds. It is mainly used to produce packaging products for industrial products. The materials for making such molds include cast aluminum, stainless steel, bronze, etc.