Methods of Plastic Molding PP-spunbond-non-woven-fabric-equipment
DATE：2021/2/25 8:44:50 / READ： / SOURCE：This station
Methods of Plastic Molding PP-spunbond-non-woven-fabric-equipment
Injection molding
Injection molding, also known as injection molding, is the use of injection machine will melt the plastic quickly injected into the mold, and solidified to get a variety of plastic products. This method can be used for almost all thermoplastics (except fluoroplastics), and can also be used for the formation of some thermosetting plastics. Injection molding accounts for about 30% of plastic parts production. It has the advantages of complex shape, precise size and high productivity. But the cost of equipment and mold is higher, mainly used for the production of large quantities of plastic parts.
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The injection molding machine is commonly used with plunger type and screw type two kinds, the figure on the right is screw type injection molding diagram. Injection molding principle: the powder granular raw materials from the hopper into the cylinder, plunger advance, the raw materials are pushed into the heating area, and then through the shunt shuttle, through the nozzle will be injected into the mold cavity, cooling plastic products after opening the mold. In order to eliminate the stress, stable size and performance of plastic parts, it is usually necessary to carry out proper post-treatment after plastic injection parts are taken out of mold cavity. In addition, there are burrs and sprue removal, polishing, surface finishing and so on. PP-spunbond-non-woven-fabric-equipment handern.com
Folding extrusion
Extrusion forming is the use of screw rotating pressure way, continuously squeeze the plasticized plastic into the mold, through a certain shape of the die mouth, and get the shape of the plastic profile suitable for the shape of the die. Extrusion forming accounts for about 30% of plastic products, mainly used for a certain section, large length of a variety of plastic profiles, such as plastic pipes, plates, rods, sheets, strips, materials and complex section of profiled materials. It is characterized by continuous forming, high productivity, simple die structure, low cost, close organization and so on. Except fluoroplastics, almost all thermoplastics can be extruded, and some thermosetting plastics can also be extruded.
The figure on the right is a sketch of spiral extrusion forming. The granular plastic is fed into the spiral propulsion chamber from the hopper, and then sent to the heating zone by the rotating screw to melt and be compressed. Under the action of the helical force, it is forced to pass through the extrusion die with a certain shape, and the profile consistent with the shape of the die section is obtained. A plastic part of a conveyor that is cooled and hardened by spraying air or water after falling on the belt.
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Folding press molding
Pressing forming, also known as compression forming, compression forming, molding forming, is the solid granule or prefabricated sheet material to join the mold, through heating and pressure method, so that its softening and melting, and under the action of pressure cavity, solidification of plastic parts. Forming is mainly used for thermosetting plastics, such as phenolic, epoxy, organic silicon, etc. It can also be used to press thermoplastic polytetrafluoroethylene products and polyvinyl chloride (PVC) records. Compared with injection molding, pressing molding equipment, mold is simple, can produce large products; But the production cycle is long, the efficiency is low, difficult to realize automation, difficult to produce thick wall products and complex shape products.
The following figure is the sketch diagram of pressing forming. Generally, the pressing forming process can be divided into several stages: feeding, mold closing, exhaust, curing and demoulding. After demoulding, plastic parts should be treated in the same way as injection molding plastic parts.
Folding blow molding
Blow molding (plastic secondary processing) is the hollow plastic billet with the help of compressed air blowing deformation, and after cooling the shaping of the plastic parts processing method. The main methods are hollow blow molding and thin film blow molding.
The figure on the right is the sketch diagram of extrusion and blowing forming of hollow parts. The tubular billet with a certain temperature is placed in the split blow mold, the mold is closed, compressed air is blown through the blowing pipe, the billet is blown to be close to the mold wall, and the hollow parts are taken out after pressure holding, cooling and shaping.
Author：admin