According to the different molding methods, the types o […]
According to the different molding methods, the types of plastic processing molds corresponding to different process requirements can be divided, mainly including injection molding molds, extrusion molding molds, blister molding molds, and high-foamed polystyrene molding molds.
1. Plastic injection (plastic) mold
It is primarily a molding die that is most commonly used in the production of thermoplastic products. The corresponding processing equipment for the plastic injection mold is a plastic injection molding machine. The plastic is first heated and melted in the heating cylinder at the bottom of the injection machine, and then melted in the screw of the injection machine. Or driven by the plunger, the injection molding machine nozzle and the casting system of the mold enter the mold cavity, the plastic is cooled and hardened, and the product is demolded. Its structure is generally composed of molding parts, pouring system, guiding parts, push-out organization, temperature adjustment system, exhaust system, support parts and other parts. The production materials generally use plastic mold steel modules, and the commonly used materials are mainly carbon structural steel, carbon tool steel, alloy tool steel, high-speed steel, etc. The injection molding processing method is generally only suitable for the production of thermoplastic products. The plastic products produced by the injection molding process are very wide. From daily necessities to various messy machinery, electrical appliances, and transportation parts, they are all molded by injection molds. It is the most widely used processing method in the production of plastic products.
2. Plastic compression mould
It includes two structural mold types: compression molding and injection molding. They are the primary type of mold used to mold thermoset plastics, and their corresponding equipment is a pressure molding machine. The compression molding method is based on the characteristics of the plastic. The mold is heated to the molding temperature (usually 103°—108°), and then the measured compression powder is put into the mold cavity and the feeding chamber, and the mold is closed. The plastic is under high heat and high pressure. It is a softened viscous flow, and after a certain period of time, it is solidified and shaped into the desired product shape. The difference between injection molding and compression molding is that there is a separate feeding chamber. The mold is closed before molding. The plastic is preheated in the feeding chamber and is in a viscous flow state. It is adjusted and extruded into the mold cavity under pressure to harden and form. Shrink molds are also used to mold some special thermoplastics, such as hard-to-melt thermoplastics (such as polyvinyl fluoride) blanks (cold molding), resin lenses with high optical performance, finely foamed nitrocellulose car steering wheels, etc. . Compression molds are mainly composed of cavity, feeding cavity, guiding organization, pushing out parts, heating system, etc. Injection molds are widely used for packaging electrical components. The material used in the production of the compression mold is basically the same as that of the injection mold.
3. Plastic extrusion mould
A type of mold used to mold successive shapes of plastic products, also called extrusion molding heads, is widely used in the processing of pipes, rods, monofilaments, plates, films, wire and cable coatings, and profiles. The corresponding production equipment is a plastic extruder. The principle is that the solid plastic is melted and plasticized under the conditions of heating and the screw of the extruder to rotate and pressurize, and the cross-section is the same as the shape of the die through a die of a specific shape. Successive plastic products. The production materials mainly include carbon structural steel, alloy tools, etc. Some extrusion dies will also be inlaid with wear-resistant materials such as diamond on the parts that require wear resistance. The extrusion process is generally only suitable for the production of thermoplastic products, and its structure is significantly different from injection molds and compression molds.
4. Plastic blow mould
It is a mold used to form plastic container hollow products (such as beverage bottles, daily chemical products and other packaging containers). The forms of blow molding are extrusion blow molding, hollow molding, injection blow molding, and hollow molding. , Injection stretch blow molding hollow molding (commonly known as "injection stretch blow"), multilayer blow molding hollow molding, sheet blow molding hollow molding, etc. The corresponding equipment for blow molding of hollow products is generally called a plastic blow molding machine, and blow molding is only suitable for the production of thermoplastic products. The blow mold structure is relatively simple, and the materials used are mostly made of carbon.
5. Plastic blister mold
It is a kind of mold that uses plastic plates and sheets as the material to form some simpler plastic products. The principle is to use the vacuuming method or the compressed air molding method to make the plastic plates and sheets fixed on the concave or convex mold. Under the condition of heating and softening, it deforms and sticks to the cavity of the mold to obtain the desired molded product. It is mainly used for the production of some daily necessities, food, and toy packaging products. The blister mold is made of cast aluminum or non-metal materials because of the low pressure during molding, and the structure is relatively simple.
6. High foamed polystyrene molding die
It is a mold for using expandable polystyrene (beads composed of polystyrene and foaming agent) material to form various foamed plastic packaging materials in various desired shapes. The principle is that the expandable polystyrene can be steam molded in the mold, including two types of simple manual molds and hydraulic straight-through foam plastic molds. They are mainly used to produce industrial packaging products. The materials for making this kind of mold include cast aluminum, stainless steel, bronze and so on.