Basic knowledge and technology application of plastic mould

The plastic processing industry is equipped with plastic forming machines to give plastic products complete configuration and accurate size tools.
   due to the variety and processing method of plastics, the structure of plastic molding machine and plastic products is complex and simple, so the type and structure of plastic mold is also diverse.
General classification of mould: it can be divided into plastic mould and non plastic mould
  (1) non plastic mold: casting mold, forging mold, stamping mold, die casting mold, etc.
   A. casting mold -- faucet and pig iron platform
   B. forging die automobile body
   C. stamping die -- computer panel
   D. die casting die super alloy, cylinder block
  (2) plastic mold
   according to different production processes and products, it can be further divided into:
A. Injection mold -- TV shell, keyboard button (widely used)
   B. blow mold - beverage bottle
   C. compression molding die -- bakelite switch, scientific porcelain bowl and dish
   D. transfer molding die integrated circuit products
   E. extrusion die -- glue pipe and plastic bag
   F. thermoforming mold transparent packaging shell
   g. rotary molding die -- soft plastic doll
   technical application of plastic mold products
   a combined plastic mold for compression molding, extrusion molding, injection molding, blow molding and low foaming molding, which mainly includes a concave die with variable cavity composed of a concave die combined substrate, a concave die component and a concave die combined clamping plate, and a convex die with variable core composed of a convex die combined substrate, a convex die component, a convex die combined clamping plate, a cavity truncation component and a side truncation combined plate.
   coordinate changes of punch, die and auxiliary forming system. It can process series plastic parts of different shapes and sizes.
   all kinds of tools and products used in our daily production and life are closely related to molds, ranging from the base of machine tool and the shell of machine body to the shell of a screw, button and various household appliances.
   the shape of the mold determines the shape of these products, and the processing quality and precision of the mold also determines the quality of these products. Because of the different materials, appearance, specifications and uses of various products, molds are divided into casting mold, forging mold, die casting mold, stamping mold and other non plastic molds, as well as plastic molds.
In recent years, with the rapid development of plastic industry and the continuous improvement of strength and precision of general and engineering plastics, the application scope of plastic products is also expanding, such as household appliances, instrumentation, building equipment, automobile industry, daily hardware and many other fields, the proportion of plastic products is increasing rapidly. A reasonably designed plastic part can often replace many traditional metal parts.
   the trend of plasticization of industrial products and daily products is increasing.
   2. General definition of mould: in industrial production, metal or non-metal materials are made into parts or products of required shape by various presses and special tools installed on the presses through pressure. Such special tools are collectively referred to as moulds.
   3. Injection molding process description: mold is a tool for producing plastic products. It consists of several groups of parts, this combination has a forming cavity. During injection molding, the mold is clamped on the injection molding machine, the molten plastic is injected into the molding cavity, cooled and shaped in the cavity, then the upper and lower molds are separated, and the products are ejected from the mold cavity through the ejection system, and then the later mold is closed for the next injection. The whole injection molding process is cyclic.
   4. (1) the mold line is demoulded together with the product when opening the mold. The design is relatively simple, easy to process, and the cost is low, so more people use the large water mouth system for operation.
   (2) fine nozzle mold: the runner and gate are not on the parting line, generally directly on the product, so it is more complex to design more sets of nozzle parting line, and the processing is more difficult. Generally, the fine nozzle system should be selected according to the product requirements.
  (3) hot runner mold:
   the structure of this kind of mold is similar to that of the fine nozzle. The big difference is that the runner is located in one or more hot runner plates and hot pump mouths with constant temperature, and there is no cold material demoulding. The runner and gate are directly on the product, so the runner does not need demoulding. This system is also called the no nozzle system, which can save raw materials and is suitable for the situation of more expensive raw materials and higher product requirements It is difficult to work and the cost of mould is high.