The cavity of the primary injection mold is preliminarily determined according to the required precision mold shape and size. Then the flow direction and direction of each cavity mold are determined according to the conditions such as the inclusion of liquid materials, the speed of the plastic mold, etc. The area where the injection molding parts are located must be kept clean.
Adjust the injection pressure and injection speed, and align the mold for adjustment if necessary. The weight of the parts shall not exceed 30% of the injection pressure.
Use high back pressure and speed injection. Because the liquid material has a certain fluidity in the mold, the injection pressure and speed should exceed 50.
The temperature and pressure of the mold are the factors that determine the shrinkage rate. The best molding temperature should be selected according to the temperature distribution curve during mold design. The temperature control of the mold should be accurate. Before each injection, the mold surface temperature should be lower.
If the edge of the product is warped after demoulding, poor demoulding will occur, which will affect the smoothness of demoulding. The thermal stress caused by low-temperature injection shall be avoided.
Due to improper mold temperature control, the materials are not easy to inject into the mold, so the cooling water temperature should be properly increased to shorten the time and heat transfer, and proper cooling should be provided. Too high mold temperature will lead to the decline of material performance, sometimes it will maintain the thickness of parts under a certain pressure and increase the deformation of parts. It is necessary to reduce the mold temperature and part temperature as much as possible to reduce the thickness of the mold surface. It is necessary to check the mold temperature.
If the molding conditions are unreasonable, low mold temperature will reduce the plastic viscosity and local viscosity, resulting in significant reduction and large local viscosity, increasing the molding pressure and surface roughness, making molding difficult. It may also be the increase of cooling capacity of plastic products or the deformation of molds.
Low molding pressure and mold temperature will increase viscosity. When the mold temperature is low, the resin viscosity increases during molding, the viscosity increases, and the molding pressure increases, resulting in higher viscosity and increased injection pressure, which leads to difficult mold filling. It may also be that when the injection pressure and mold temperature are low, the mold has no cooling function, and the gate is too small, which is easy to be cold punched and flow dead, causing troubles to the factory. It is an effective way to improve the mold temperature, improve the production efficiency, extend the injection time, improve the production efficiency, and greatly reduce the production cost.
Therefore, when purchasing a special injection molding machine, the control injection volume and injection pressure required by the injection molding machine must be selected according to the market, use and process parameters. But we can't blindly choose the injection quantity and neglect the temperature control system of the screw metering cylinder.
Note: Before purchasing the plastic machine, it is better to choose a screw size that is 40% - 50% of the injection volume. When the temperature is higher than 85 ° C, the plastic machine will reach a lower screw volume. The metering area of the screw shall be under normal temperature.
Molten plastic injection will solidify rapidly. After thermosetting plastic melts, it needs to be supercooled and slowly remove the gap, which is conducive to exhaust vacuum. That is to say, when the solid in the molten plastic reaches the bottleneck or individual objects (such as mirrors), the supercooled screw is easy to crack first, so that the plastic sheet or other plastic sheets are easy to age and degrade. In order to avoid cracking at the same place during the shelling process, the melt pressure should be set as far as possible. The faster the injection speed is, the larger the temperature is, the larger the shrinkage is, and the easier the thermal decomposition is to occur. The actual shrinkage can generally not exceed the pipe diameter and be reduced to a certain range, the maximum can be 2-3 mm, and the temperature at the die mouth should be balanced.
All cooling water circulation systems adopt circulation channel system, and the surface of the circulation channel adopts natural cooling to keep the temperature of the die mouth constant, which eliminates the shortcomings of insufficient cooling due to temperature difference changes, shortens the cooling time, reduces the dependence on the thermal and chemical properties of the product, shortens the cycle time, and greatly saves the production cycle.
The water temperature machine is used to heat the water to the temperature of the upper and lower circulating water pools, so that the whole water temperature channel has no constant change. Water temperature machine is used to make temperature treatment mold, mainly used in hardware, plastic, printing industry and lighting industry. Introduction to the main functions of the temperature machine.
The water temperature machine is used for water recycling. Although there are many water temperature machines now, they can't do without the electric temperature controller. This is not important for most enterprises. Manufacturers will choose the automatic water supply controller first when purchasing. This is actually very important. In addition, the water temperature machine can be directly used after purchase and feeding, and many problems can be solved by using the automatic water supply controller. However, it is very convenient to use. After all, for the factory, it is generally recommended to select the plastic drain pipe, and the manual water feeder is usually selected. The manual water feeder affects the stability of water quality. To ensure good cleaning and cleaning effect, it is necessary to confirm whether cleaning is required.
● Check the water heater before opening it. Use manual method to maintain the water temperature machine, which can prolong the life of the heater. If it is used for a long time or the temperature controller is used, the water temperature machine will fail.
● Before long-term use of the water heater, please pay attention to the maintenance work, and do not store too cold food in it.
● The technicians of the manufacturer, the professional technicians of the after-sales service personnel of the enterprise, should overcool the pipes inside the water heater when maintaining the operators. If the pipes are not cold, the supercooled food stored in them should be put in water for drying or added with cold water when starting up to avoid overheating and supercooling, so as to ensure the normal operation of the mold.
● For water cooling, the service life of water cooling usually does not exceed 5-10 months. There is no need to maintain the water frequently or reheat the water frequently. If it is used in high temperature environment, only cooling water is needed.
● During the large water mill, the water shall be cooled between the water and the water. Before the cooling of the cold cooling water, when the water is cooled and condensed, we use the cooling water to cool the water hole, which will block the cooling channel and cause the water channel to block.
● When the wall thickness of the water tower is required, a cooling water channel can be opened at the place where the wall thickness is, and the heat in the cooling water channel can be timely introduced with cooling water.
● Water cooling of water tower: water will have temperature control within the predetermined temperature range, but the cooling capacity of water should be small, generally below 30 °.
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