Mold

Die muju (moju; mold; mould; die; tooling; matrix; pattern) of industrial production to injection molding, blow molding, extrusion, casting or forging molding, smelting, stamping, drawing and other methods are required for all products kinds of molds and tools. Simple classificationCategory General mold (1), also known as a single two-plate mold parting surface mold, injection molding is the most simple one, it will be parting the mold for the interface is divided into two parts: the dynamic model and fixed model. Part of the moving mold cavity, and the other part of the cavity in the fixed mold. Sprue in the fixed mold; shunt creation in the sub-type surface, a model, the products and flow remain in the dynamic simulation, dynamic model with the top part of the system. (2) three-mode formwork or two small outlets in the mold parting surface is divided into three parts, an increase of more than two board gate plate for products around a gate marks the occasion allowed, this mold into a dotted gate, so called small outlet mode, which is more complicated mold structure accordingly. Start power play with a mountain or pull the screw plate. Sort by molding method (1) is the first plastic injection molding machines to heat the barrel injection, plastic heat melting of the injection screw or plunger, driven by the nozzle and die casting system into the mold cavity, the physical and chemical role stereotypes become hardened plastic products. Injection molding by an injection, pressure (cooling) and the ejection process constitutes a plastic cycle, and therefore the characteristics of injection molding is cyclical. Molding thermoplastic injection molding cycle is short, high production efficiency, melt wear of the mold, forming large quantities of complex shape to the surface and marking a clear pattern, size and high precision plastic parts; but large plastic wall thickness cases, it is difficult to avoid forming defects. Plastic anisotropy is one of quality, all possible measures should be adopted to minimize. (2) compression molding commonly known as pressing, molding of plastic parts is the first one of the methods. Compression molding is the plastic directly to a certain temperature, the open mold cavity, and then closed mold under heat and pressure in the plastic melt into a flow state. Since the physical and chemical effects, leaving the plastic hardened into a certain shape and size of the room temperature plastic parts remain the same. Compression molding is mainly used for molding thermosetting plastics, such as phenolic molding powder, urea formaldehyde and melamine formaldehyde molding powder, glass fiber reinforced phenolic, epoxy, DAP resin, silicone resin, polyimide molding, etc., You can also unsaturated polyester molding material group (DMC), sheet molding compound (SMC), the overall pre-molding (BMC) and so on. Under normal circumstances, usually by a compression membrane, with the lower die structure, the compression mode into overflow fed, does not overflow, semi overflow-style categories. (3) extrusion molding is made of plastic in a state of viscous flow at high temperature and certain pressure, by the shape of a specific section of the die, and then at a lower temperature, the required cross section shape as a continuous profile A molding method. Extrusion molding production process is ready to shape the material, extrusion molding and cooling, pulling and cutting, extrusion products after the treatment (quenching and tempering or heat treatment). In the extrusion molding process, pay attention to adjust the heating section of the extruder barrel and die head temperature, screw rotation, traction speed and other parameters in order to get qualified extrusion profiles. With particular attention to adjusting the polymer melt in the extrusion die head speed. Because when the molten material extrusion rate is low, the extrudate has a smooth surface, uniform cross sectional shape; but when the melting rate of the material out of reach a certain limit, the extrudate surface becomes rough and dull , there shark skin, orange peel pattern, shape distortion and so on. When the extrusion rate further increases, the extrudate surface distortion, or even fragmented and broken into pieces or melt column. So out of control speed is essential. (4), also known as pressure casting molding injection molding. Plastic raw material is preheated in the feed room to join, and then pressurized cylindrical mold lock chamber into the feed, through the pressure column pressure to the plastic, plastic at high temperature, high pressure melting as the mobile state and into the cavity through the feed system gradually solidified into plastic parts. This molding method, also known as transfer molding. Injection molding for the lower than solid plastics, in principle, capable of compression molding of plastic, can also be pressure injection molding method. But requires forming material in the lower curing temperature, the molten state has a good liquidity, higher than the curing temperature, have a greater cure rate. (5) by the extrusion blow molding or injection is to be obtained, and is still in the plasticized state trends in tubular or sheet billet in the fixed mold, and immediately pass into the air, forcing the billet material and affixed to the mold expansion parietal surface, and after cooling, after ejection stereotypes, that they need a processing method insulating products. Suitable for blow molding of plastic high-pressure polyethylene, low-pressure polyethylene, PVC, soft PVC, polystyrene, polypropylene, polycarbonate and so on. Forming method according to the different type of blank, hollow extrusion blow molding can be divided into hollow blow molding and injection blow molding two. Extrusion Blow Molding has the advantage of extruders and extrusion blow molding of the structure is simple, the disadvantage is the parison wall thickness is inconsistent, likely to cause uneven thickness of plastic products. Right is a schematic diagram of extrusion blow molding hollow. Advantages of injection blow molding hollow parison wall thickness is uniform, no flash, due to injection of parison with bottom, so the bottom does not produce hollow products, and joint fight, not only beautiful but also high strength. The disadvantage is the use of expensive molding equipment and molds, so that molding method used for mass production of small hollow products, and in the use of hollow extrusion blow molding method is not widely used.