The pressure control and metering system is performed by the oil-pressure injection moulding machine, and all movements are carried out by the oil road responsible for:
Screw rotation in the plasticization phase;
slide seat material passage (the nozzle is close to the injection bushing);
Axial motion of the shot screw during injection and pressure protection;
Close the substrate to the shot rod until the elbow lever is fully extended or the piston die stroke has been completed;
Start the top bar to top out the component. On a full-voltage machine, all movements are performed by a brushless synchronous motor with permanent magnets. The rotational motion is transformed into linear motion through the ball bearing screw, which has been used in the machine tool industry.
The efficiency of the entire process depends in part on the plasticization process, in which screw plays a crucial role. The screw must ensure that the material is melted and homogenized. This process can be adjusted with counterpressure to avoid overheating.
The mixing element smelting element smelting element stoking does not produce excessive flow rate, otherwise, it will lead to polymer degradation. Each polymer has a different maximum flow rate, and if this limit is exceeded, the molecule sways and the polymer main chain breaks. However, the focus remains on controlling the forward axial motion of the screw during injection and pressure retention. The subsequent cooling process, including intrinsic stresses, tolerances and warping, is important to ensure product quality. All of this is determined by the quality of the mold, especially when optimizing the cooling channel and ensuring effective closed-loop temperature regulation.
The system is completely independent and does not interfere with mechanical adjustment. Mold movements such as closed molds and top-out must be precise and efficient. Speed distribution curves are typically used to ensure that moving parts are accurately close. Contact maintenance can be adjusted. It can therefore be concluded that the quality of the product is mainly determined by the system that controls the forward movement stage of the screw, without regard to energy consumption and mechanical reliability, with the same additional conditions (e.g. mold quality).
On oil-pressure injection moulding machines, this adjustment is achieved by detecting oil pressure.
Specifically, the oil pressure activates a set of valves through the control plate, and the fluid acts through the manipulator and is regulated and released. Injection speed control includes open-loop control, semi-closed-loop control and closed-loop control. The open-loop system relies on a common proportional valve.
Proportional tension is applied to the desired proportion of the fluid, thus causing pressure to be generated in the injection barrel, allowing the injection screw to move at a certain forward speed. The semi-closed-loop system uses a closed-loop proportional valve. The loop is closed at the position where the closure port is located, which controls the proportion of oil flow by moving within the valve. The closed-loop system is closed when the screw pans the speed. The speed sensor (usually a potometer type) is used in the closed-loop system to detect a decrease in tension at a time.
The oil flowing out of the proportional valve can compensate for the speed deviation that occurs by adjusting it. Closed-loop control relies on dedicated electronic components integrated with the machine. Closed-loop pressure control ensures uniform pressure during injection and pressure retention, as well as back pressure uniformity in each cycle.
The proportional valve is adjusted by detecting the pressure value, and the deviation is compensated according to the set pressure value. In general, hydraulic monitoring can be carried out, but detecting melt pressure in the nozzle or cavity is another effective method. A more reliable solution is to manage the proportional valve by reading the nozzle or cavity pressure reading.
Adding temperature detection on the basis of pressure detection is particularly beneficial for process management. Understanding the actual pressure that materials can withstand is also helpful in predicting the actual weight and size of the molded parts based on the set pressure and temperature conditions. In fact, by changing the pressure pressure value, more material can be introduced into the mold cavity to reduce component shrinkage and meet design tolerances, including preset injection molding shrinkage. As the melting condition approaches, the semicrystalline polymer shows a significant change in ratio. In this regard, overcharging does not prevent the component from topping out.