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 machine, the plastic enters the mold cavity through the nozzle of the injection machine and the gating system of the mold. The plastic is cooled, hardened and shaped, and then demoulded to obtain the product. Its structure usually consists of molding part, pouring system, guiding part, pushing mechanism, temperature control system, exhaust system, supporting part and so on. The manufacturing materials are usually plastic die steel modules, and the commonly used materials are mainly carbon structural steel, carbon tool steel, alloy tool steel and high speed steel. Injection molding is usually only suitable for producing thermoplastic products. Injection molding produces a wide range of plastic products, from daily necessities to various complex machinery, electrical appliances, vehicle parts and so on. It is the most widely used processing method in plastic products production.

Plastic mold

Plastic mold is a tool that is matched with plastic molding machine in plastic processing industry to give plastic products complete shape and accurate size. Due to the diversity of plastics and processing methods, as well as the complexity of plastic molding machines and plastic products, the types and structures of plastic molds are also diverse.

1 Basic introduction

One? Compression molding? Squeeze? Injection molding? A combined plastic mold for blow molding and low foaming molding mainly comprises a female die with a variable cavity composed of a female die combined substrate, a female die assembly and a female die combined splint, and a male die with a variable core composed of a male die combined substrate, a male die assembly, a male die combined splint, a cavity cutting assembly and a side section combined plate. Coordinated change of punch, die and auxiliary forming system of stamping die. Can process a series of plastic parts with different shapes and sizes. Plastic processing industry and plastic molding machine are matched, given? Plastic products are tools with complete configuration and precise dimensions. Due to the diversity of plastics and processing methods, as well as the complexity of plastic molding machines and plastic products, the types and structures of plastic molds are also diverse.

With the rapid development of plastic industry and the continuous improvement of the strength of general plastics and engineering plastics, the application scope of plastic products is also expanding, and the consumption of plastic products is also increasing.

Plastic molds are tools for producing plastic products. It is composed of several groups of parts, and there is a molding cavity in this combination. During the injection molding process, the mold is clamped. On the injection molding machine, molten plastic is injected into the molding cavity, cooled and molded in the cavity, then the upper and lower molds are separated, the product is ejected from the cavity through the ejection system, and finally the mold is closed for the next injection. The injection molding process is cyclic.

Generally speaking, a plastic mold consists of a moving mold and a fixed mold. The moving die is installed on the moving die plate of the injection molding machine, and the fixed die is installed on the fixed die plate of the injection molding machine. During injection molding, the movable mold and the fixed mold are closed to form a gating system and a cavity. When the mold is opened, the movable mold and the fixed mold are separated, and the plastic product is taken out.

Although the structure of the mold may be ever-changing due to the variety and performance of plastics, the shape and structure of plastic products and the types of injection molding machines, the basic structure is the same. The mold is mainly composed of gating system, temperature control system, molding parts and structural parts. Among them? Gating system and molded parts are the parts that are in direct contact with plastics, and they change with plastics and products. They are the most complex and diverse parts in plastic molds, which need the highest machining smoothness and precision.

The gating system refers to the part of the runner before the plastic enters the cavity from the nozzle, including the main runner, the cold material hole, the shunt runner and the gate. Molded parts refer to all kinds of parts that constitute the shape of products, including moving dies, fixed dies and cavities, cores, forming rods, exhaust ports, etc.

Driven by the application demand of high-tech and pillar industries, China's plastic molds have formed a huge industrial chain, from the upstream raw and auxiliary materials industry and processing and testing equipment to the downstream. In several major application industries, such as machinery, automobiles, motorcycles, home appliances, electronic communications, building materials and so on. Plastic molds are developing vigorously.

With the rapid development of automobiles, household appliances, electronic communication and various building materials in China.

Chapter * * * 12 of the report on in-depth investigation and investment prospect of China plastic mould market. First of all, it introduces the overall operation of the plastic mould industry in the world and the market development environment of the plastic mould industry in China. Then, it analyzes the market operation of plastic mould industry in China, and introduces the competition pattern of plastic mould market in China. Subsequently, the report analyzes the operating conditions of key enterprises in China, and finally analyzes the development trend and investment forecast of China's plastic mold industry. If you want to have a systematic understanding of the plastic mold industry, or want to invest in the plastic mold industry, this report is an indispensable tool for you.

2 main categories

According to the different molding methods, the types of plastic processing molds corresponding to different technological requirements can be divided, mainly including? Injection mold, extrusion mold, plastic suction mold, high? Foamed polystyrene molding die, etc.

1, plastic injection (plastic) mold

It is one of the most widely used products in the production of thermoplastic parts? Forming mold, plastic injection mold corresponding processing equipment is plastic injection molding machine. The plastic is first heated and melted in the heating barrel at the bottom of the injection molding machine, and then melted in the injection molding machine. Driven by screw or plunger, it enters through the nozzle of injection molding machine and the gating system of mold? Mold cavity, plastic cooling hardening molding, demoulding to get the product. Its structure usually consists of molding part, pouring system, guiding part, pushing mechanism, temperature control system, exhaust system, supporting part and so on. What are the commonly used manufacturing materials? The common material of plastic mould steel module is mainly carbon structural steel. Carbon tool steel? Alloy tool steel, high speed steel, etc. Injection molding is usually only suitable for producing thermoplastic products. Injection molding produces a wide range of plastic products, from daily necessities to various complex machinery, electrical appliances, vehicle parts and so on. It is the most widely used processing method in plastic products production.

2. Plastic die

Include compression molding and injection molding. They are mainly used for molding thermosetting plastics, and the corresponding equipment is 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 feeding chamber, closes the mold, and the plastic becomes soft and sticky under the action of high temperature and high pressure, and after a certain period of time, it is solidified and molded into the required product shape. The difference between pressure injection molding and compression molding is that there is a separate feeding chamber. Before molding, the mold is closed and the plastic is preheated to a viscous state in the feeding chamber. Under the action of pressure, it is adjusted and extruded into the mold cavity and hardened. Die is also used to shape some special thermoplastics, such as thermoplastic (such as polyvinyl fluoride) blanks that are difficult to melt (cold pressing), with high optical performance? Resin lens, micro-foamed nitrocellulose steering wheel, etc. The die is mainly composed of cavity, feeding cavity, guiding mechanism, ejecting parts and heating system. Injection molds are widely used to package electronic components. The materials used to manufacture the compression mold are basically the same as those used in the injection mold.

3, plastic extrusion die

A kind of mold used for molding and producing continuous plastic products, also known as extrusion molding head, is widely used in? Processing of pipes, bars, monofilaments, plates, films, wire and cable coatings, special-shaped materials, etc. What is the corresponding production equipment? The principle of plastic extruder is that solid plastic is melted and plasticized under the condition that the extruder screw is heated, rotated and pressurized, and a continuous plastic product with the same cross section and mold shape is made through a mold with a specific shape. Its manufacturing materials are mainly carbon structural steel and alloy tools. Some extrusion dies will be inlaid with wear-resistant materials, such as diamond, in the parts that need wear-resistance. Extrusion process is usually only suitable for producing thermoplastic products, which is obviously different from injection mold and compression mold in structure.

4. Plastic blow mold

It is a mold for molding hollow products of plastic containers (such as packaging containers for beverage bottles and daily necessities). According to the process principle, the main forms of blow molding are extrusion blow molding, injection blow molding, injection stretch blow molding (commonly known as "injection stretch blow molding"), multi-layer blow molding, sheet blow molding and so on. The equipment corresponding to blow molding of hollow products is usually called plastic blow molding machine, and blow molding is only suitable for producing thermoplastic products. The structure of the blow mold is relatively simple, and the materials used are mostly carbon.

5, plastic mold

It is a kind of mold that takes plastic plates and sheets as raw materials to shape some simple plastic products. The principle is that the plastic plates and sheets fixed on the female die or the male die are deformed under the condition of heating and softening, and the required molded products are obtained, which are mainly used for producing some daily necessities, foods and toys. Because the pressure of plastic suction mold is low during molding, so? Mold materials are mostly cast aluminum or non-metallic materials, and the structure is relatively simple.

6, high foaming polystyrene molding die

Is it application developability? Using polystyrene (bead material composed of polystyrene and foaming agent) as raw material, foam plastic packaging materials with various required shapes are formed. Its principle is that expandable polystyrene can be formed by steam in the mold, including simple manual operation mold and hydraulic press straight-through foaming mold, which is mainly used to produce packaging products of industrial products. What material is this mold made of? Cast aluminum, stainless steel, bronze, etc.

3 design elements

Mold design and manufacturing? Plastic processing is closely related. The success or failure of plastic processing depends largely on the effect of mold design and the quality of mold manufacturing, and the basis of plastic mold design is the correct design of plastic products.

Structural elements to be considered in plastic mold design are:

(1) parting surface, that is, the contact surface between the female die and the male die when clamping. The choice of its position and form is influenced by the product shape and appearance, wall thickness, molding method, post-processing technology, mold type and structure, demoulding method and molding machine structure.

(2) Structural parts, namely, sliding block, inclined top, straight top block, etc. Complex molds. The design of structural parts is very important, which is related to the life, processing cycle, cost and product quality of dies. Therefore, the design of complex mold core structure is very important for designers. Require comprehensive ability, and try to pursue a simpler, more durable and more economical design scheme.

(3) mold accuracy, that is, avoiding jamming, accurate positioning, guide posts, positioning pins, etc. Positioning system is related to the appearance quality of products, the quality of molds and the service life. According to the different mold structures, different positioning methods are selected, and the positioning accuracy control mainly depends on mechanical processing. The positioning of internal model is mainly for designers to consider designing a more reasonable and easy-to-adjust positioning method.

(2) The gating system, that is, the feeding channel from the nozzle of the injection molding machine to the cavity, includes the main runner, the shunt runner, the gate and the cold cavity. In particular, the selection of gate position should be conducive to the molten plastic filling the cavity in a good flowing state, and the solid runner and gate cold material attached to the product are easy to be ejected from the mold and taken out (except the hot runner mold) when the mold is opened.

③ Plastic shrinkage and its influence on products? Factors of dimensional accuracy, such as? Mold manufacturing and assembly errors, mold wear, etc. In addition, what should be considered when designing compression mold and injection mold? Matching of technological parameters and structural parameters of molding machine. It has been widely used in plastic mold design. Computer aided design technology.