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5, injection device backward and mold ejection products
Screw after the plasticizing measurement, in order to make the nozzle not for a long time in contact with the cold mould to form a cold material, such as often need to nozzle from the mold, the injection device back. Procedures for it or not, or have the action, the machine can choose. Molten material within the cavity after cooling to finalize the design, the clamping device shall rise mode, and automatically top products.
3. Injection molding and operations
3.1 the working principle of injection molding machine
For the working principle of injection molding machine and injection syringe are similar, it is with the help of a screw or plunger of thrust, will has good plasticizing molten state (that is, the viscous flow state) plastic injection into the closed good cavity, after curing finalize the design the product process.
Injection molding is a process of circulation, each cycle mainly includes: quantitative feeding, plasticizing, injection pressure, melt filling mold cooling, and pick-up. After take out the plastic mold closing again, for the next cycle.
3.2 the structure of the injection molding machine
Injection molding machine according to the way of plasticizing pided into plunger type injection molding machine and screw injection molding machine, press machine transmission mode and can be pided into hydraulic, mechanical and hydraulic, mechanical (rod), according to the operation mode is pided into automatic, semi-automatic, manual injection molding machine.
(1) horizontal injection molding machine: this is the most common type. The clamping part and injection part center online at the same level, and the mould is opened along the horizontal direction. Its characteristic is: the fuselage short, easy to operation and maintenance; Low center of gravity, installation is relatively stable; Products out after use gravity fall automatically, easy to realize automatic operation. At present, the injection molding machine on the market use this kind of type more.
(2) vertical injection molding machine, the clamping part and injection part in the same vertical center line, and the mould is opened along the vertical direction. As a result, it covers an area of small, easy to put insert, it's convenient to make loading and unloading of the mould, the materials from the hopper into the plasticizing more evenly. But not easy to automatically after products out, must be removed by hand, not easy to realize automatic operation. Vertical injection made for small injection molding machine, general is to use more below 60 grams of injection molding machine, large and medium-sized machine should not be used.
(3) the Angle of injection molding, direction and its injection mold interface in the same plane, it is especially suitable for machining center parts are not allowed to leave the gate marks the plane of the products. It covers an area smaller than horizontal injection molding machine, but fell into the mould insert is easy to tilt. This type of injection made for small machine.
(4) the multimode disc injection molding machine: it is a kind of transfer operation special injection molding machine, characterized by a clamping device used the rotating disc structure, mould around the axis of rotation. This type of injection molding machine give full play to the plasticizing capacity of injection device, can shorten the production cycle, improve the machine's production capacity, and therefore particularly suitable for cooling to finalize the design or due to put long insert and need more auxiliary time of production of large quantities of products. But because of the large, complex mold clamping system, mould clamping force of clamping device is often small, so this kind of injection molding machine in plastic soles, etc. Products widely applied in production.
Injection molding machine generally include injection device, clamping device, hydraulic system and electric control system and other parts.