What are the squeezing, pressing, blowing plastic, pressing, sucking (vacuum molding) and rolling molding molding

The molding and processing method of plastic

M plastic molding processing is an engineering technology. The content involved is to transform plastic into various processes of plastic products. The following or several cases often occur during the transition, such as the flow of the polymer and the changes in physical and chemical properties.

Plastic molding method

1. Compressed mold. Compression molding is also called mold pressure. It is the molding method of molding in the closed mold cavity with the help of pressure (generally heated). Generally, compressed molds are suitable for thermosetry plastic, such as phenolic plastic, amino plastic, unsaturated polyester plastic, etc.
The compressed mold molding consists of three processes: pre -compression, preheating and mold pressure:
is pre -pressure to improve the quality of the product and improve the molding efficiency, etc. Operation.
The preheating In order to improve the processing performance of molding molding and shorten the molding cycle, the operation of the mold before forming is heated before forming.
The mold pressure adds the required plastic in the mold, closed the mold, exhaust, and maintains the operation of the molding temperature and pressure for a period of time, and then removes the mold and clear the mold.
The main equipment for compressed molding is crusher and molding. The most used for the pressure machine is the self -sufficient hydraulic machine, ranging from tens of tons to hundreds of tons. There are underwriters and upper pressure crusher. The molds used for compressing molds are called suppression molds, divided into three categories; overflow molds, semi -overflowing molds are not overflowing molds.
The main advantage of compressed molding is the products and capable of mass production of large planes. The disadvantage is that the production cycle is long and the efficiency is low.
2. Layer pressure forming. Using or without adhesives, two or more layers of the same or different materials with heating or pressure are used to combine the same or different materials to the overall method.
This pressure forming is commonly used for operation. The dynamic pressure plate of this pressure machine and the fixed pressure plate are equipped with a multi -layer floating thermal pressure plate.
The enhanced materials commonly used in layers include cotton cloth, glass cloth, paper, asbestos, etc. The resin has phenolic, epoxy, unsaturated polyester, and certain thermoplastic resin.
3. Cold pressure molding. Cold pressure molds are also called cold -pressure sintering types. The difference between ordinary compressed mold is that the material is pressed at room temperature. The molding mold after the mold can be heated or solidified by the help of chemical effects. This method is mostly used for the formation of polytrafluoroethylene, and it is also used for certain high -temperature -resistant plastics (such as polyimide, etc.). The general process is three steps: billet-sintering-cooling.
4. Pass the mold. Transmitting mold molding is a way of molding of thermosetry plastic. When molding, the mold plastic is heated and softened in the heating room, and then crushed into the heated mold cavity in the heating mold cavity. There are different types of modules in the device: ① live plate type; ② can; ③ plunger type.
The requirements for plastic plastics are: Before reaching the curing temperature, the plastic should have a large fluidity. After reaching the curing temperature, it must have a faster curing rate. This requirement is phenolic, melamine formaldehyde, and epoxy resin.
This molding has the following advantages: ① The product is small and can be reduced to reduce the amount of processing; ; ③ Product performance is uniform, accurate size, and high quality; ④ The wear of the mold is small. The disadvantage is: ⑤ The manufacturing cost of the mold is higher than that of the compressed mold; ⑥ Plastic loss is large; ⑦ Fiber enhances plastic due to fiber direction, and the plastic surrounded by the embedded parts is sometimes The intensity is reduced.
5. Low -pressure molding. The use of molding pressure or less than 1.4 MPa is used.
The low -pressure molding method is used to make enhanced plastic products. Enhanced materials such as glass fiber, textiles, asbestos, paper, carbon fiber, etc. Most of the commonly used resins are thermosetry, such as phenolic, epoxy, amino, unsaturated polyester, and silicon.
The low -pressure molding includes bag pressure and jet method.
(1) Bag pressure molding. With the help of elastic bags (or other elastic septums), the fluid pressure is received to make the uniformly compression of the enhanced plastic between the rigid mold and the elastic bag and become a method. According to different methods that cause fluid pressure, it can generally be divided into compression bag molding, vacuum bag pressure molding, and thermal pressure kettle forming.
(2) Jet molding. When forming an enhanced plastic product, the short -cut fiber and resin are sprayed on the mold to accumulate and solidify into the product at the same time.
6. Squeeze out for molding. The extruded molding is also called extruded molds or squeezing. It is a method of continuously forming the material through the mobilization state through heating and pressurizing in the extruder.
The extrusion method is mainly used for the molding of thermoplastic plastic, and can also be used for certain thermosetry plastic. The extruded products are continuous profiles, such as tube, stick, silk, plate, film, wire and cable cover layer, etc. In addition, it can be used for plastic mixing, plasticized granules, coloring, and mixing.
The extruder is composed of the main part of the extrusion device, the transmission mechanism and heating, and the cooling system. There are two types: screw type (single screw and multi -screw) and plunger type. The former’s extrusion process is continuous, the latter is intermittent.
The basic structure of a single screw extrusion machine mainly includes the transmission device, feeding device, tube, screw, head and mouth molds.
The auxiliary equipment of the extruder has three major processing equipment (such as material transportation and dryness), squeezing material treatment equipment (setting, cooling, traction, cutting or rolling), and production conditions control equipment. kind.
7. Squeeze and shape. The squeezing molding is one of the methods for the molding of thermosetry fiber to enhance plastic. It is used to produce sections of fixed -fixed shapes and unlimited lengths. The molding process is to pull the continuous fiber of the impregnated resin glue through the heating mold, and then further solidify the resin through the heating room to prepare a unidirectional and high -intensity continuous enhancement of plastic profiles.
The resin is usually used for squeezing and shaped. There are three types: unsaturated polyester, epoxy and silicon. Among them, unsaturated polyester resin uses the most.
The squeezing molding machine is usually composed of fiber discharge device, resin slot, pre -molded device, oral mold and heating device, traction device and cutting equipment.

8. Injection molding. Injection molding (injection molding) is a method that makes the thermoplastic or thermosetable molds be evenly plasticized in the heating cylinder, and then pushed from the plunger or movement to the mold cavity of the mold cavity.
The injection molding is almost applicable to all thermoplastic plastic. In recent years, injection molding has also been successfully used for certain thermosetry plastic. The molding cycle of the injection molding (a few seconds to a few minutes), the quality of the molding product can be from a few grams to tens of kilograms. It can be molded with a complicated shape, accurate size, and metal embedded. Therefore, this method has strong adaptability and high production efficiency.
The injection machine for injection molding is divided into two categories: plunger -type injection machine and screw -type injection machine. It consists of three parts: injection system, mold lock system, and plastic mold; its molding method can be divided into:
(1) exhaust -type injection molding. The exhaust -type injection of the exhaust -type injection molding application has an exhaust port in the middle of the tube and is also connected to the vacuum system. When plastic plasticized, the vacuum pump can make the water vapor, single, volatilizer in plastic pumps in plastic pumps. Sexual substances and air are drawn through the exhaust port; raw raws do not have to dry up to improve production efficiency and improve product quality. It is particularly suitable for moisture -absorbing materials such as polycarbonate, nylon, organic glass, and cellulose.
(2) flow injection molding. Moral injection molding can be used for ordinary mobile screw injection machines. That is, the plastic is continuously plasticized and squeezed into the mold cavity with a certain temperature. After the plastic is full of cavity, the screw stops rotating. The thrust of the screw is used to keep the materials in the mold at the right time under pressure, and then cool down. Liquid injection molding has overcome the equipment restrictions of large -scale products, and the quality of the parts can exceed the maximum injection volume of the injection machine. It is characterized by plastic objects that are not storage in the leaflet, but constantly squeezing into the mold, so it is a method of combining and injection.
(3) A total of injection molding. A total injection molding is an injection machine with two or more injection units, plastics with different varieties or different colors, and at the same time or inject it into the mold. This method can produce a variety of colors and (or) composite products with a variety of plastics. The representative co -injection molding is dual -color injection and multi -color injection.
(4) The flow of the flowing channel is formed. There is no downturn in the mold, and the extended nozzle of the injection machine directly divides the melting material into the molding method in each mold cavity. During the injection process, the plastic in the runner maintains a melting flow, and does not get off with the product during the release, so there is no flowway residue in the decoration. This molding method not only saves raw materials, reduces costs, but also reduces the process to achieve fully automatic production.
(5) The reaction injection molding. The principle of reaction injection molding is to pump the reaction raw material through the measurement device and pump into the mixed head, collide in the mixed head, and then injected high -speed into a closed mold, quickly solidify, remove the mold, and remove the product. It is suitable for processing polyurethane, epoxy resin, unsaturated polyester resin, organic silicon resin, and alcoholic acid resin. It is currently mainly used for polyurethane processing.
(6) Injecting of thermosetry plastic. The granular or group -like thermosetry plastic, in the tube that strictly controls the temperature, is plasticized into a sticky state through the effect of the screw. Under higher injection pressure, the material enters a certain temperature range of the mold and solidification. In addition to changes in physical state, thermosetry plastic injection molding also has chemical changes. Therefore, compared with thermoplastic plastic injection molding, there is a big difference in molding equipment and processing processes. The following table compares the difference between thermosetry and thermoplastic plastic injection.
The comparative comparison of thermosetry and thermoplastic plastic injection molding conditions

Texing thermos plastic thermoplastic plastic n The temperature plasticization temperature of the tube is low, the temperature of the tube is below 95 ° C, the temperature control requirements requirements High -plasticized temperature, the temperature of the tube is above 150 ° C, the temperature control is not strict
The long time in the tube
n Mold temperature 150 1 ° C
In injection pressure 100-200MPa 35-140MPa
The injection volume is small, the remaining material in the front of the barrel is small, the front of the tube is large, and the front part of the tube There are many remaining materials

The injection molding of thermosetry plastic is phenolic plastic most.
9. Blow molding. By gas pressure, the heat -blew in the mold into a hollow product, or a method of bleeding into a tube film without mold. This method is mainly used for manufacturing of various packaging containers and tube membranes. Anyone with a melt index is 0.04 ~ 1.12 is a relatively excellent hollow blowing material, such as polyethylene, polyvinyl chloride, polystyrene, polystyrene, thermoplastic polystol, polycarbonate, polyamide, acetate cellulose, and polymerization polymerization Aldehyde shrinking resin, among which polyethylene is used most.
(1) Injecting blow molding molding. The plastic is made into a bottom -type blank with an injection molding method, and then the type blank is moved to the blowing mold into a hollow product.
(2) Squeeze out and blow molding. The squeezing method is used to make the plastic into a bottom -type blank, and then move the blank into the blowing mold into a hollow product.
The difference between the injection blow molding and the extrusion blow molding molding is that the method of manufacturing blank is different. The process of blowing plastic is basically the same.
Except for the injection machine and extrusion machine, the mold blowing equipment is mainly the mold for blowing plastic. Blowing molding molds are usually synthesized by two petals, including cooler channels, and small holes on the typical surface can be inserted into the pressure gas blowing pipe.
(3) Stretching and blowing forming. Stretching and blowing molding is a type of blowing molding for double -axis orientation stretching. The method is to first stretch the type, and then use the compressed air to blew to the horizontal stretch. Stretching and blowing molding can make the product’s transparency, impact strength, surface hardness, and rigidity, which is suitable for polyetry and polyethylene glycol (PETP) blowing molding.
This -stretching and blowing molding includes: injection type blank is set towards stretching and blowing plastic, extruded type blank settled to stretching and blowing plastic, multi -layer orientation stretching and blowing plastic, compressed forming orientation stretching and blowing plastic.
(4) Blowing the film method. A method of molding thermoplastic film. The squeeze is squeezed into a tube in anger, and then the air blowing into the tube continuously expands it to a certain size of the tube film.
The plastic film can be made in many methods, such as blowing plastic, extrusion, flowing, pressure delay, casting, etc., but the most widely used application method is used.
This is suitable for manufacturing the film such as polyethylene, polyvinyl chloride, and polyamide.
10. casting. Without pressure or slightly pressurizing, the liquid monomer, resin or mixture is injected into the mold and made it a solid product. The casting method is divided into static casting, embedded casting, centrifugal casting, slusing plastic, rotating casting, rolling plastic and flowing plastic.
(1) Static casting. Static casting is two methods that are simpler and widely used in cast molding. This method is commonly used in liquid monomer, some polymerized or retractable slurry, polymer and single solution of the monomer, with a additive (such as cause, curing agent, promotional agent, etc.), or thermoplastic resin melt casting into the model The cavity is formed.
(2) embedded casting. Embedded casting, also known as sealing for molding, is a forming technology that packs various samples and parts into the middle of the plastic. The embedded items are soon placed in the mold, injected with liquids such as monomers, prefabricated or polymers, and then converged or solidified (or hardening) to remove the mold. This technology has been widely used in the electronic industry. Plastic varieties used for this type of formation include cheese formaldehyde, unsaturated polyester, organic glass and epoxy resin.
(3) centrifugal casting. Centrifugal casting is a method of forming a pipe or hollow -like product with centrifugal force. The quantitative liquid resin or resin dispersed into the container (that is, the mold) of the quantitative liquid resin or resin scattered through the extruder or the dedicated funnel to make it rotate at a high -speed single axis (dozens of rotation per minute to two thousand rotations). At this time, put it at this time. The input materials are forced to be distributed on the near wall of the mold. While rotating, the material placed is curing, and then the product can be obtained as required to be cooled or post -treatment. Increased enhanced fillers can be added at the same time when molding enhanced plastic products.
Illaded casting is usually used with hot plastic plastic plastic plastic with less melting viscosity and good thermal stability, such as polyamide and polyethylene.
(4) Small. Sstech plastic is a method of molding hollow products. During the mold, the plastic paste is in the hollow mold of the plastic paste, until the prescribed capacity is reached. The mold should be heated before or after the material, so that the material becomes a gel in the inner wall of the mold. When the gel reaches the predetermined thickness, pour out excessive liquid materials and heat it to melt it. After cooling, you can peel out the products from the mold. The plastic for slimming is mainly polyvinyl chloride.
(5) Rotate plastic. This method is to load liquid materials into a closed mold and rotate it at a lower speed (several times to dozens of rotations per minute). After heating or cooling to solidify or harden, you can get the product from the mold. The rotation of a single axis is used to produce cylindrical products, while the dual axis or vibration movement is used to produce closed products.
(6) Roll plastic (rotating molding). Similar to a forming method of rotating and casting, the difference is that the materials used are not liquid, but sintering dry powder. The process is to put the powder into the mold and make it rotate around the two vertical axles, heated and uniformly melt it on the inner wall of the mold, and then cooled to get hollow products from the mold.
The polyethylene, modified polystyrene, polyamide, polycarbonate, and cellulose plastic used.
(7) Streaming and casting. A method of making a film. During the manufacturing, the liquid resin or resin scattered the flow on the carrier (usually a metal belt), and then solidify (or harden) it in an appropriate method, and finally strip the film from the carrier.
plastic used for the production of an delayed film is: triacerocytic acid cellulose, polyethylene, chlorolythalene, and ethyl acetate, etc. Essence

11. Hand -shaped. Hand paste is also known as hand -shaped and forming and contacting. It is one of the ways to make enhanced plastic products. This method is on the mold of the molding agent, and puts the resin on the side of the reinforcement material on the other side until the thickness is required until the thickness is required. The synthetic resin adopted in the shaped type is mainly epoxy resin and unsaturated polyester resin. The enhanced materials include glass cloth, non -twisted coarse gauze cloth, glass felt, etc.
12. Fibrous wound forming. Under the condition of controlling tension and predetermined line type, continuous silk wrapped into core molds or molds with resin glue to enhance plastic products on the core mold or mold. This method is only suitable for making cylindrical and spherical turns. Commonly used resins include phenolic resin, epoxy resin, unsaturated polyester resin, etc. Glass fiber is a commonly used enhanced material for wounding. There are two types: there are twist fiber and non -twist fiber.
13. Pressure extension. The thermoplastic plastic is connected into a film or sheet for molding by linking and extension through a series of heating rollers. The pressure -crusted products include film, sheets, artificial leather and other coating products. The raw materials used for pressure extension are mainly polyvinyl chloride, cellulose, and modified polystyrene.
The pressure device includes pressure extension and other auxiliary machines. The pressure extension is usually classified by the number of rollers and its arrangement. Depending on the number of rollers, the pressure extension machines include double rollers, three rollers, four rollers, five rollers, and even six rollers.
14. Coated. For the purpose of anti -corrosion, insulation, decoration, etc., the surface of fabrics, paper, metal foils, or plates such as liquid or powder is placed on the surface of objects such as plastic thin layers (eg.0.3 mm).
The most commonly used plastic in coating method is generally thermoplastic plastics, such as polyvinylene, polyvinyl chloride, polyamide, polyvinyl, polytetrachloride, etc.
The coating process has hot melting compresses, fluidization spraying, flame spraying, electrostatic spraying and plasma spraying.
(1) Hot melt. Use compressed air to spray the plastic powder through the surface of the workpiece that spray guns and spray guns, and the plastic melts and cools to form a coverage layer.
(2) fluidization spray. The preheated workpiece is immersed in the resin powder in the container with suspended resin powder to melt and adheres to the surface.
(3) flame spray. A method of molting the spraying resin through the cone -shaped flame area of ​​the muzzle to achieve spraying.
(4) Static spray. The use of high -voltage electrostatic can cause a static field, that is, the workpiece is grounded, and the plastic powder is equipped with negative charge when the plastic powder is sprayed, and the plastic static electricity is sprayed on the workpiece.
(5) Plasma spray. Use a plasma spray gun to make the inert gas flowing through the plasma incident area (such as the hybrid gases of gaseous, nitrogen, and radon) to become a high -speed high -energy plasma flow at 5500 ~ 6300 ° C. Roll powder -like resin is sprayed at high speed to melt into the surface of the workpiece to melt into a melting into the surface of the workpiece. coating.
15. Foam molding. Foam molding is the process of making plastic production of microporous structure. Almost all thermosetry and thermoplastic plastic can be made into foam plastics. Commonly used resins include polystyrene, polyurethane, polyvinyl chloride, polyethylene, phenolic formaldehyde, phenolic formation.
The foam plastics can be divided into two types according to the foam structure. If most stomachs are connected to each other, it is called an open hole foam plastic; Bubble plastic. The foam structure of opening or closing is determined by the manufacturing method.
(1) Chemical foam. The chemical foam agent specially added, the gas generated by the heating decomposition or the component of the raw material group, the plastic melt is full of bubbles. The gases released by chemical foaming agents during heating include carbon dioxide, nitrogen, ammonia, etc. Chemical foam is commonly used in the production of polyper foam plastics.
(2) Physical foam. Physical foaming is a method of dissolving gas or liquid in plastic, and then the method of swelling or gasification foaming. There are many plastic varieties adapted to physical foam.
(3) Mechanical foam. Take the mechanical mixing method to mix the gas into the liquid mixture, and then form a foam plastic of the foam through the setting process. This method is often used for sleeping formaldehyde resin, such as polyethylene alcohol -shrinking formaldehyde, polyethylene ethylene, and polyvinyl chloride solution.
16. Two -time molding. The second formation is one of the methods of plastic molding processing. Taking plastic profiles or blanks as raw materials, it makes it a way to become the need for -shaped products through heating and external force.
(1) Hot forming. Thermal formation is a method of molding thermoplastic plastic sheet to soften. Under gas pressure, liquid pressure or mechanical pressure, it uses appropriate molds or fixtures to make it a way to make it into a product. There are many methods of plastic thermal forming. Generally, it can be divided into:
moder pressure molding using single -mode (yang or yin mold) or counter -mold. Using external mechanical pressure or self -weight It is different from the molding molding of a processing. This method is suitable for all thermoplastic plastics.
The differential pressure molding adopts single mold (yang or yin mold) or pairing mold, or if the mold is not used, under the influence of the gas pressure pressure, the heating to the soft plastic sheet is closely attached to the mold. Modern method of various products. Differential pressure molding can be divided into vacuum molding and air pressure molding.
The thermal forming is particularly suitable for manufacturing of products with large walls and large surface area. Commonly used plastic varieties include various types of polystyrene, organic glass, polyvinyl chloride, ABS, polyethylene, polyacryl, polyamide, polycarbonate, and polyzed phenyl acetate.
The thermal formation equipment includes clamping systems, heating systems, vacuum and compressed air systems and molding molds.
(2) Double -axis stretch. To re -directional thermoplastic thin film or plates, the two -way stretching process is specially made above the glass. The stretching is between the glass -based temperature and melting point of the polymer. After the directional stretching and the thin film or single silk after the room temperature, the mechanical properties in the stretch direction are greatly improved.
The polymer suitable for orientation stretch is: polyvinyl chloride, polyzhexyl glycolin glycol, polytatochloride, polymethyl acrylic methyl, polyethylene, polypropylene, polystyrene, polyzyrene And some styrene cluster.
(3) Solid phase molding. The solid -phase molding is a method for thermoplastic plastic profiles or blank materials to form it into a product under pressure. The molding process is below the melting (softening) temperature of the plastic (at least less than 10-20 ° C). All are solid -phase. Among them, the non -crystalline plastic is above the glass -based temperature, and the high bomb area below the melting point is often called thermal forming, and the processing below the glass temperature is called cold molding or room temperature. It is also often called plastic. Cold processing method or normal temperature plastic processing.
This has the following advantages: short production cycle; improvement of the toughness and strength of the product; simple equipment, can produce large and super -large products; reduced costs. The disadvantage is that it is difficult to produce complex and precise products; the production process is difficult to control, and the products are easy to deform and crack.
The solid phase molding includes: sheet rolling, deep stretching or stamping, hydraulic molding, extrusion, cold stamping, roller forming, etc.
17. Secondary processing. Formed plastic products or profiles, processed by required, such as mechanical processing, connection, modification, etc. The following table lists the method of plastic secondary processing.

M plastic secondary processing method

classified processing method
mechanical processing sawing, cutting, rushing, car, shaving, drilling, grinding, polishing, polishing, polishing, polishing, polishing, polishing, polishing, polishing, polishing, polishing, polishing, polishing, polishing, polishing, polishing, polishing, polishing, and polishing, Sand spraying, kneading, thread processing, etc.
The laser processing, punching, engraving, etc. , Infension, etc., bonding solvents, solutions, hot melt, etc.
mechanical screws, spring clips, spring plugs, riveting, hinges, etc. , Painted, hot printing, vacuum coating, spray plating, electroplating, etc.

6. The purpose of plastic

plastic 巳 is widely used in agriculture, industry, construction, packaging, national defense The cutting -edge industry and people’s daily life are all areas.
Agricultural: A large amount of plastic is used for manufacturing film, seedling film, large shed film and discharge pipes, fish nets, breeding floats, etc.
If industry: Electrical and electricity uses plastic to make insulation materials and packaging materials widely; in the mechanical industry, it is made of plastic to make transmission gears, bearings, bearing tiles and many components instead of metal products; plastic in the chemical industry; Pipelines, various containers and other anticorrosive materials; do doors and windows, staircase handrails, floor bricks, ceilings, insulation insulation boards, wallpapers, water drop pipes and pits, decorative boards and sanitary ware in the construction industry.
In national defense industry and cutting -edge technology, whether it is conventional weapons, airplanes, ships, missiles, artificial satellites, spacecraft and atomic energy industry, plastic is indispensable materials.
It in people’s daily life, plastic applications are more widely used, such as plastic sandals, slippers, raincoats, handbags, children’s toys, toothbrushes, soap boxes, hot water bottle shells and so on. At present, it has also been widely used in various household electrical appliances, such as televisions, inclusion machines, electric fans, washing machines, and refrigerators.
M plastic, as a new type of packaging material, has been widely used in the packaging field, such as a variety of hollow containers, injection molding containers (turnover boxes, containers, barrels, etc.), packaging film, woven bags, corrugated boxes, foam plastic plastic , Tie rope and packaging belt.

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