Sign of injection production technology of two large overview | injection plate making
Guangzhou sign factory
Sign of injection production technology of two overview sign injection molding is an engineering technology, it involves content is plastic into useful and can keep the original performance of sign products.
Injection molding is important process conditions affect the plasticizing flow and cooling temperature, pressure and the corresponding each action time, give you a brief introduction below an overview of the injection plate making technology;
A 1, cylinder temperature, temperature control of injection molding process, the need to control the temperature of the material barrel temperature, nozzle temperature and mould temperature, etc.
The first two main influence plastic plasticizing temperature and flow, and then a temperature is mainly influence plastic flow and cooling.
Each kind of plastic flow with different temperature, the same kind of plastic, due to different sources or brand, the flow temperature and decomposition temperature is little different, this is due to the different average molecular weight and molecular weight distribution, plastic in different type of injection machine of plasticizing process is also different, so choose the cylinder temperature is not the same.
2, nozzle temperature, nozzle temperature is usually slightly lower than expected tube maximum temperature, this is to prevent the molten material in straight through the nozzle possible & other
Salivate phenomenon throughout the &;
Nozzle temperature also cannot too low, otherwise will cause early setting of melting and the nozzle blocking, or due to early coagulation material into the cavity affect the performance of the products.
3, mold temperature, mold temperature on the sign of internal performance and apparent impact on the quality.
Mold temperature is determined by the plastic, the size of the sign and structure of the crystalline, performance requirements, and other process conditions,
Melting temperature, injection speed and injection pressure, molding cycle, etc. )
Second, the pressure control of injection plate production process including plasticizing pressure and injection pressure, and directly affects the quality of plasticizing and plastic products.
1, plasticizing pressure (
USES screw injection machine, screw at the top of the molten material in the screw rotating back pressure is called the plasticizing, which is also called back pressure.
The size of the pressure can be found on the overflow valve to adjust the hydraulic system.
In injection, the size of the plasticizing pressure is with the screw rotation speed is constant, the pressure increase plasticizing when raise the temperature of the melt, but will reduce the speed of the plasticizing.
In addition, increase plasticizing pressure often can make the melt temperature uniformity, color mixing and discharge gas in the melt.
The decision of the general operation, the plasticizing pressure should be on the premise of guarantee the sign quality is lower, the better, the specific values are vary with the varieties of the plastic, but usually rarely more than 20 kg/cm2.
2, the injection pressure in current production, almost all the injection pressure of injection machine are in piston or screw at the top of plastic pressure (
By the oil pressure conversion)
Injection pressure in injection molding, the role of is, to overcome the flow resistance of plastic flowing from cylinder cavity, given the rate of molten material molding and compaction of molten material.
Three, molding cycle time required to complete an injection molding process, molding cycle, also known as the molding cycle.
Directly affect the forming period of labor between birth rate and utilization rate of equipment, in the process of production, therefore, should be on the premise of guarantee quality, try to shorten the molding cycle time of all.
In the molding cycle, with injection time and cooling time is the most important, they have a decisive influence on the quality of signs.
Mold filling time of injection time is directly on the mold filling rate, for the production of molding time is about 3 ~ 5 seconds.
The holding time of injection time is the cavity pressure time, plastic in the large proportion in the whole injection time, generally about 20 ~ 120 seconds (
Thick parts can be up to 5 ~ 10 minutes)
At the gate before freezing, melting the holding time, influential to sign size accuracy.
The holding time are the most value, known it depends on the material temperature, die temperature and the mainstream and the size of the gate.
If the mainstream way and the size of the gate and process conditions are normal, usually is to get products shrinkage range minimum pressure value shall prevail.
Cooling time mainly depends on the thickness of the plastic signs, thermal and crystallization properties of plastics, and mould temperature, etc.
The end of the cooling time should be in place to ensure that the sign demoulding when not cause changes for the principle, generally between 30 to 120 seconds.
Cooling time is too long is not necessary, not only reduce the production efficiency, the complex parts will also cause demoulding difficulty, even the forced demoulding will produce mold release stress.
Other time of the molding cycle is linked to the production process is continuous and automatic and two degree and so on.