⒈ injection pressure
　　injection pressure provided by the hydraulic system of the injection molding system. Pressure in the cylinder is transmitted to the screw plastic melt by injection molding, the plastic melt is driven under pressure through the nozzle into the mold of the injection molding machine vertical flow passage (for a portion of the mold is also sprue), sprue, split channel, and through the gate into the mold cavity, this process is the injection molding process, or is called the filling process. There is a pressure to overcome the resistance of the melt flow process, or conversely, the presence of the flow resistance during the pressure required to counteract the injection molding machine, to ensure smooth progress of the filling process.
　　During injection, the maximum pressure at the nozzle of the injection molding machine, to overcome the flow resistance of the entire melt. Thereafter, the flow pressure along the length of the most distal end to melt gradually reduce the wavefront, if the exhaust gas inside the cavity well, the front end of the last melt pressure is atmospheric pressure.
　　Many factors affect the melt filling pressure, summed up in three categories: ⑴ material factors such as the type of plastic, such as viscosity; ⑵ structural factors, such as the gating system type, number and position, and shape of the mold cavity of the article ⑶ molding process elements; thickness.
　　⒉ injection time
　　here refers to the time of injection of the plastic melt time is required to fill the cavity, does not include mold opening, closing and other auxiliary time. Although the injection time is very short, for the molding cycle has little effect, but to adjust the time for the pressure injection sprue, runner and cavity control has a great effect. Reasonable injection times facilitate the melt over the filling, but also to improve the surface quality of the article and to reduce the dimensional tolerance has a very important significance.
　　Injection time is much lower than the cooling time, the cooling time is about 1/10 ~ 1/15, this rule can be used as the basis of all plastic parts forming the prediction time. When modulo flow analysis, only in the case where the melt is completely driven by the rotation of the screw filled cavity, the injection time of the analysis result is equal to only the injection molding process conditions set time. If the hold pressure switching screw occurs before the cavity is filled, then the results will be greater than the set of process conditions.
　　Injection temperature ⒊
　　Injection temperature is an important factor affecting the injection pressure. Injection molding machine with a barrel heating zones 5-6, each material has its appropriate processing temperature (processing temperature can be found in the detailed data provided by the material supplier). Injection temperature must be controlled within a certain range. Temperature is too low, poor plasticizing melt, affect the quality of the molded article, increasing the difficulty of the process; temperature is too high, the raw material is easily decomposed. In the actual injection molding process, the injection molding temperature is often higher than the cylinder temperature, the higher the value of the injection rate and properties of the material concerned, up to 30 ℃. This is due to the melt when subjected to a shear generated by the injection port due to a high heat. When the mold flow analysis for this difference can be compensated for in two ways, one is trying to measure the temperature of the melt during the injection space, the other model is also included into the nozzle.
　　⒋ holding pressure and time
　　during the injection molding process is near the end of the screw stops rotating, only forward, this time into the injection holding pressure stage. Holding pressure during the injection molding machine nozzle continuously fed into the cavity, to fill the vacated The molding shrinkage volume. If the cavity not filled with packing, parts in approximately 25% shrinkage, in particular due to the contraction of the muscle is too large shrinkage marks formed. Holding pressure is generally about 85% of the maximum filling pressure, of course, be determined according to the actual situation.
　　⒌ backpressure
　　backpressure is meant that the time needed to overcome the stocker screw reverse reverse pressure. High back pressure and facilitate melting plastic pigment dispersion, but at the same time extending the screw retraction time, the length of the plastic fibers is reduced, increasing the pressure of the injection molding machine, so the back pressure should be low, generally no more than Injection 20% of the pressure. Foam injection molding, a high back pressure than the gas to be formed, or a screw may be pushed out of the cartridge. Some back-pressure molding machine may be programmed to compensate for the reduced length of the screw during melting, this will reduce the heat input, allowing the temperature to drop. However, since the result of this change is difficult to estimate, it is difficult to make corresponding adjustments to the machine.