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PE Pipe Fitting Mould Process Conditions
- May 26, 2017 -

PE Pipe Mold Injection Molding The most important three process conditions are temperature, pressure and time: The temperature: PE pipe parts belong to the thick wall, in order to avoid cooling when the temperature is too large to cause internal stress, PE Pipe Fitting Mould the barrel temperature should be lower value. Barrel temperature distribution, generally from hopper to nozzle temperature from low to high, so that the plastic temperature rise steadily to achieve uniform plasticizing. To prevent the plastics from overheating, the temperature near the nozzle section is slightly lower. Mold temperature on the product intrinsic performance and appearance of a great impact on the PE, in addition to mold rate, die temperature will directly affect the crystallization and crystallization of the product configuration. Therefore, polyethylene (PE) pipe mold suitable for the use of medium mold temperature, for polyethylene (PE) materials, the cooling rate is appropriate, the crystallization of plastic moderate, with good physical and mechanical properties. Pressure: Pressure in the injection process includes back pressure and injection pressure. When using screw-type injection molding machine, the pressure of the top of the screw is called back pressure when the screw rotates backwards.

Generally, the increase of back pressure will make the temperature uniformity and mixing uniformity of polyethylene (PE) melt. The increase of back pressure also helps to expel the gas in the melt and increase the degree of densification of the melt, thus increasing the injection quantity of the machine. For polyethylene (PE) raw materials, increasing back pressure can increase the melt temperature, group and color uniformity. Time: During the whole molding cycle, the injection time and cooling time have a decisive effect on the product quality.

Barrel temperature: The barrel temperature is mainly related to the density of PE and the flow rate of the melt, and is related to the type and performance of the injection moulding machine and the shape of the first plastic part. Because PE is a crystalline polymer, the grain must absorb a certain amount of heat during melting, so the barrel temperature should be higher than its melting point 10 degrees. In the case of LDPE, the barrel temperature control in the 140, HDPE barrel temperature control in 220 Shan, the bottom of the barrel to take the minimum value, the front end to take the maximum value. The softening temperature range of PE is small, PE Pipe Fitting Mould and the melt is easy to oxidize, therefore, in the molding process should be as far as possible to avoid contact between the melt and oxygen, so as not to reduce the quality of plastic parts; The non-Newtonian property of PE melts is not obvious, the change of shear rate has little effect on viscosity, and the viscosity of PE melts is less affected by temperature.

Mold Temperature: Mold temperature has a great effect on the crystallization of plastic parts, high mold temperature, melt crystallinity, high strength, PE Pipe Fitting Mould but the shrinkage will also increase. Usually LDPE mold temperature control in 30 Shan Simo 45 Shan, and HDPE temperature correspondingly higher 10 20.

Injection pressure: To improve injection molding pressure is conducive to the filling mold, because the fluidity of PE is very good, so in addition to thin-walled slender products, should be excellent selection of lower injection pressure, general injection pressure for 50 100mpa. PE Pipe Fitting Mould The shape is simple. After the wall of the larger plastic parts, injection pressure can be lower, otherwise high.