Precision closed-loop hydraulic system for injection molding machines

The hydraulic system control of injection molding machine evolved from the manual remote control to the pressure single-proportional control, and then upgraded to the pressure and flow double proportional control, and the hydraulic system principle is still open-loop control, which is only used as a control means to improve the level of automation, but does not improve the accuracy of the injection molding state. At present, Baston has launched the closed-loop control technology of the hydraulic system, which greatly improves the accuracy of each action of the injection molding machine, especially the injection metering, and truly reflects and creates a strong advantage of price-performance ratio.
1. The amount of glue injection is stable and the repeatability is accurate
The closed loop of the hydraulic system is based on the principle of high-response control, the pressure and flow device has built-in displacement sensing function, and the differential feedback is corrected by the controller high-speed operation, and the highest frequency of pressure and flow can ensure the stability and repeatability accuracy of each injection amount.
2. The qualification rate of products has been greatly improved
Due to the stability and accuracy of each injection amount greatly improved, after the mold test measurement is determined, the accuracy of each injection measurement is automatically controlled, so as to improve the qualification rate of the product, especially when the mold cavity is processed with multi-cavity products, the mold cavity will lack corners and less material to cause defective products. If the system closed-loop control is used, the stability of the injection amount can always be guaranteed, and the repeatability of the injection can be completely guaranteed, and the benefits are the most obvious
3. It is most suitable for the processing of thin-walled and deep-cavity products
Generally, the processing of thin-walled products requires quick response and stable speed of glue, but the open-loop control of the traditional system is always easy to change, and cannot be automatically controlled feedback correction, resulting in poor uniformity of products, uneven thickness, uneven transparency, flashing, silver grain phenomenon and other unstable phenomena, and the use of system closed-loop feedback control, its stability is extremely reliable, can ensure the quality requirements of such products
4. The amount of materials used is accurate and the benefits are remarkable
Because the system adopts closed-loop feedback control, it can achieve fast response frequency, accurate control, stable measurement each time, less change, and small difference, so the injection material is always stable, unlike the traditional open-loop control of glue injection measurement is unstable, insufficient material quantity causes waste, excess resulting in product flashing, mold expansion and other defects, long-term can not ensure quality and reasonable consumption, resulting in loss of benefits.
5. Achieve ideal accuracy and solve difficult product processing
For the processing of products with high dimensional accuracy requirements, uneven wall thickness and easy cold shrinkage, and the processing of products with poor fluidity and fast fluidity requirements of melting, due to the high response function of closed-loop control injection molding machine, it can fully meet or reduce the unsatisfactory problems in product processing, such as IC cards, high-grade lenses, mobile phones, cameras and other shell boxes, etc.
6. Promote overall productivity and improve machine service life
In view of the closed-loop control of the injection molding machine system fast response, stable operation, thereby significantly reducing the production process machine operating time, in addition to the smooth system switching, eliminating impact and crawling, so that the action cycle will be smoother, to ensure the service life of the machine dynamics, so that customers can obtain maximum benefits.
Don't talk about the injection molding machine with open loop control mode, most of the domestic and Taiwan-Hong Kong double-proportional PQ valve control injection molding machines used now are open loop control methods.
There are two main ways to solve the control problem of closed-loop injection molding only from hydraulic control technology: the first is the full servo control system. SINGLE OR MULTIPLE SERVO VALVES CAN BE CONFIGURED TO ACHIEVE PRECISE CONTROL OF SINGLE OR MULTIPLE ACTIONS, AND ITS RESPONSE EFFICIENCY CAN REACH MORE THAN 100HZ, WITH EXCELLENT STEADY-STATE AND DYNAMIC PERFORMANCE. The second is a closed-loop proportional control system. Includes closed-loop proportional valves and closed-loop proportional variable displacement pumps. These two components are developed on the basis of conventional proportional valves and proportional variable displacement pumps, and have reached high quality over the years. Although the first scheme has high control accuracy, it has high cost, high requirements for hydraulic system pollution, and relatively few applications. The second scheme has an excellent performance-price ratio and is a control element widely used in medium and high-grade injection molding machines.