Six classifications of plastic moulds

Wed Feb 01 20:59:42 CST 2023

Plastic molds are tools in the plastic processing industry that are used in conjunction with plastic molding machines to give plastic products a complete configuration and precise dimensions. According to the different molding methods, there are different types of molds.

1. Injection Molds

The plastic is firstly heated and melted in the barrel at the bottom of the injection molding machine, and then pushed by the screw or plunger of the injection molding machine, it enters the mold cavity through the injection molding machine nozzle and the pouring system of the mold, the plastic is cooled and hardened, and the product is obtained by releasing the mold.

Its structure usually consists of molding parts, pouring system, guiding parts, pushing out mechanism, temperature regulating system, exhaust system, supporting parts and other parts, and the manufacturing is made of plastic mold steel. Injection molding processing method is usually only applicable to the production of thermoplastic products, plastic products produced by injection molding process is very wide, from daily necessities to all kinds of complex electrical appliances, automotive parts, etc. are formed with injection molds, it is the most widely used in the production of plastic products a processing method

2. Blow molding molds

Used to shape plastic containers hollow products (such as beverage bottles, daily necessities and other packaging containers) of a mold, blow molding form according to the process principle mainly extrusion blow molding hollow molding, injection blow molding hollow molding, injection extension blow molding hollow molding (commonly known as injection pull blow), multi-layer blow molding hollow molding, sheet blow molding hollow molding, etc.. Blow molding of hollow products corresponding to the equipment is usually called plastic blow molding machine, blow molding is only applicable to the production of thermoplastic varieties of products. Blow molding mold structure is relatively simple, the materials used are mostly made of carbon more then.

3. Extrusion Molds

A class of molds used to mold and produce continuous shaped plastic products, also called extrusion molding heads, are widely used for processing pipes, rods, monofilaments, sheets, films, wire and cable cladding, profiles, etc.

Its corresponding production equipment is a plastic extruder, whose principle is to melt and plasticize solid plastic under the conditions of heating and extruder's screw rotation and pressure, and make continuous plastic products with the same cross-section as the shape of the mouth mold through a specific shape of the mouth mold. Its manufacturing materials are mainly carbon structural steel, alloy tools, etc. Some extrusion dies are also inlaid with wear-resistant materials such as diamond in the parts that need to be wear-resistant.

The extrusion process is usually only applicable to the production of thermoplastic products, and its structure is distinctly different from that of injection molds and compression molds.

4. Blister mold

The principle is to use the method of vacuum opening or compressed air forming method to make the plastic plate or sheet fixed on the concave or convex mold, deformation under heating and softening and stick on the cavity of the mold to get the required molding products, mainly used in some daily necessities, food, toys and other packaging products production.

Because the pressure of blister mold is low, so the mold material is mostly made of cast aluminum or non-metal material, and the structure is simple.

5. Compression molding molds

There are two types of structural molds, compression molding and compression injection molding. They are mainly used to mold thermosetting plastics, and their corresponding equipment is pressure molding machine.

Compression molding method is based on the characteristics of plastic, the mold is heated to the molding temperature (generally at 103°108°), and then the measured compression molding powder is put into the mold cavity and the filling chamber, and the mold is closed, and the plastic is softened and sticky under the action of high heat and pressure, and then cured and shaped into the desired product shape after a certain period of time.

6. Highly expanded polystyrene molding molds

The principle is that the hair polystyrene in the mold into the steam molding, including simple hand-operated mold and hydraulic machine straight-through foam mold two types, mainly used to produce industrial products in the packaging products. The materials used in the manufacture of such molds are cast aluminum, stainless steel, bronze, etc.