Injection speed control during injection moulding

Injection speed control includes open-loop control, closed-loop control and closed-loop control options. Open-loop systems rely on shared proportional valves. Proportional tension is applied to the desired proportion of fluid so that the fluid creates pressure in the injection barrel, allowing the injection screw to move at a certain forward speed. The closed-loop system uses a closed-loop proportional valve. The loop is closed at the position where the closing port is located, and the closing port controls the flow rate of the fuel through movement within the valve. The closed loop system closes at the speed of the screw translation. A speed sensor (usually potentiometer type) is used in the closed-loop system to detect the drop in timing. Proportional valve out of the material through adjustment, can compensate for the speed deviation. Closed-loop control relies on dedicated electronic components integrated into the machine. Closed-loop pressure control ensures that the pressure is uniform during the injection and hold pressure phases, and that the back pressure is uniform throughout each cycle. The proportional valve is adjusted by the detected pressure value, and the offset is compensated according to the set pressure value. In general, hydraulic pressure can be monitored, but detecting the 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. Increasing temperature detection based on pressure detection is particularly beneficial for process management. Understanding the actual pressure that the material can withstand also helps predict the actual weight and size of the molded part based on the set pressure and temperature conditions. In fact, by changing the dwell pressure value, more material can be introduced into the mold cavity to reduce component shrinkage and meet design tolerances (including preset injection shrinkage). The semi-crystalline polymer shows a great change in specific volume when approaching the melting conditions. In this regard, overfilling does not prevent the ejection of components.