Introduction of Five Plastic Molds

Plastic molds are tools used in conjunction with plastic molding machines to give plastic products a complete structure and precise dimensions. Depending on the molding method used, different types of molds can be classified.

1. Injection mold for plastic molding

It is the most commonly used type of molding molds in the production of thermoplastic plastic products. Injection molds correspond to injection molding machines. First, the plastic is heated and melted in the heating barrel at the bottom of the injection molding machine. Then, under the push of the screw or plunger of the injection molding machine, the plastic enters the mold cavity through the injection system of the injection molding machine and the mold. The plastic cools and solidifies to form the finished product after demolding.

Its structure usually consists of molding components, injection systems, guiding components, ejection mechanisms, temperature adjustment systems, exhaust systems, support components, etc., and is manufactured using plastic mold steel. The plastic molding process is usually only suitable for the production of products of thermoplastic plastic. Plastic products produced by injection molding are widely used, from daily necessities to various complex electrical and automotive parts. It is the most widely used processing method in the production of plastic products.

2. Blow molding mold for plastic molding

A mold used to produce plastic container products (such as various packaging containers for beverages and daily chemicals), blow molding forms mainly include extrusion blow molding, injection blow molding, injection stretch blow molding (commonly known as ISB), multilayer blow molding, and sheet blow molding. The equipment corresponding to the blow molding products is usually called a plastic blow molding machine, and blow molding molds are only suitable for the production of thermoplastic plastic products. The structure of the blow molding mold is relatively simple, and the materials used are mostly made of carbon structural steel.

3. Extrusion mold for plastic molding

A type of mold used to produce continuous plastic products, which is also called an extrusion head. It is widely used in the processing of pipes, rods, monofilaments, sheets, films, wire and cable insulation layers, special-shaped materials, etc. The corresponding production equipment is a plastic extruder. Its principle is that the solid plastic is melted, plasticized under the conditions of heating and the rotation and pressure of the screw of the extruder, and then made into a continuous plastic product with the same section as the die through a specific shaped die. Its manufacturing materials mainly include carbon structural steel, alloy tools, etc., and some extrusion molds also use wear-resistant materials such as diamond on parts that require wear resistance. The extrusion process is usually only suitable for the production of thermoplastic plastic products, and it has significant differences in structure from injection molds and compression molds.

4. Vacuum molding mold for plastic molding

A type of mold used to produce some simple plastic products with plastic plates and sheets as raw materials. The principle is to use a vacuum method or compressed air molding method to make the plastic plates or sheets fixed on the concave or convex mold deform and adhere to the mold cavity to obtain the required molded product. Plastic molded parts are mainly used in the production of daily necessities, food, toys, and other packaging products.

5. Compression mold for plastic molding

It includes two types of structural mold types: compression molding and transfer molding. They are mainly used to shape thermosetting plastics, and the corresponding equipment is a pressure molding machine. According to the characteristics of plastics, the compression molding method heats the plastic mold to the molding temperature, and then puts the measured compression molding powder into the mold cavity and feeding chamber, closes the mold. Under high temperatures and pressures, the plastic softens and flows. After a certain period of time, it solidifies and takes shape. 

Transfer molding differs from compression molding in that there is no separate feeding chamber. Before molding, the mold is first closed, and the plastic is preheated to a flow state in the feeding chamber, and then adjusted to be squeezed into the mold cavity under pressure to harden and form. Compression molds mainly consist of the cavity, feeding cavity, guiding mechanism, ejection parts, heating system, etc. Transfer molds are widely used in the packaging of electronic components. The materials used to make compression molds are basically the same as those used in injection molds.