Precision gear injection molding, gear injection molding mold production,
plastic mold injection molding production
Method for setting injection molding process
Temperature: drying temperature of raw materials, forming temperature of material drums, mold temperature, oil temperature of forming equipment
Pressure: clamping force, injection pressure, holding pressure, back pressure, ejection pressure, etc
Speed: mold opening and closing speed, injection molding, pressure holding speed, material storage speed, ejection speed, etc
Time: mold opening and closing time, injection time, pressure holding time, material storage time, neutron core pulling time
1. Temperature
（1） Barrel temperature
The temperature of the material barrel should be maintained between the melting temperature and decomposition temperature of the plastic, depending on the type of injection molding machine and material (material sensitivity to temperature); The method to determine whether the temperature setting of the material barrel is reasonable: 1. Injection method to the air; 2. Product appearance observation method;
（2） Nozzle temperature
The setting is slightly lower than the maximum temperature of the barrel, mainly to prevent salivation, and the decrease in temperature will be compensated for by the shear effect of the plastic material on the screw.
（3） Mold temperature
Mold temperature refers to the temperature of the mold wall in direct contact with plastic, which directly affects the filling flow performance of plastic, the cooling rate of the product, the molding cycle, and the crystallization, orientation, shrinkage, and other results of the product. It is an important factor affecting the appearance and size of the product.
（4） Drying temperature
The drying temperature of plastic in a dryer is generally greater than four hours, and the moisture content needs to be less than 0.05%.
2. Pressure
（1） Plasticization pressure
In an injection molding machine, the screw pressure set when the screw rotates backward is called plasticizing pressure or back pressure. Excessive or insufficient pressure can lead to poor material storage.
（2） Maintaining pressure
When the mold cavity is completely filled, the screw of the injection molding machine often does not immediately retreat, but stays in its original position or moves slightly forward, keeping the injection pressure for a period of time, which is commonly referred to as holding pressure.
（3） Injection pressure
Injection pressure refers to the force exerted by the screw on the unit area of molten plastic inside the barrel during injection molding. Its function is to make the molten material in the barrel overcome the resistance of the injection molding machine nozzle and mold pouring system, fill the mold cavity with a certain speed and pressure, and compact the material in the mold cavity. Generally, it is necessary to distinguish between absolute pressure and relative pressure.
The setting of injection molding process comes from the characteristics of raw materials and mold flow analysis. Continuous optimization during the trial molding process to achieve the final mass production state is the stable process parameter.
