Improved design vertical injection molding machine hydraulic system

Date：2014/11/27 11:19:37

Scientific and technological advances, plastics in all areas of the national economy has become an indispensable material, plastic injection molding machine is to achieve a major plastics processing machinery and equipment. Injection molding cycle generally consists of four parts: the injection time, cooling time, mold opening and closing times, the auxiliary time. Wherein the auxiliary time including product ejection time and Choucha core time. For medium-sized complex molds, auxiliary time about 10% to 15% of the molding cycle. In the injection molding production process, the various stages of operation of the injection molding cycle sequence relation exists, there is overlapping relationship, thereby allowing shortening the molding cycle. But each operation is limited overlapping relationship, and therefore can not be efficiently shorten the molding cycle. Existing vertical injection molding machines are generally used to improve the hydraulic proportional technology, double pumps, accumulators, mechanical, electro-hydraulic proportional control technology, servo motor, external hydraulic control to improve the production cycle, but with these methods are relatively high cost. Therefore, based on the original vertical injection molding machine, how to apply common hydraulic components, the existing vertical injection molding machine to optimize the design and improve the production cycle, to improve their efficiency and ensure the quality of products is important.
         The author of a vertical injection molding machine to improve the design, the two neutron hydraulic valve in parallel vertical injection molding machine, hydraulic oil line parallel neutron after the oil port to connect the top of the cylinder into the oil chamber, the neutron the oil outlet connection back to the top of the cylinder oil chamber. Neutron improved hydraulic vertical injection molding machine can not only shorten the molding time and improve efficiency in injection molding, while the pulling mechanism to achieve two speeds, slow realization among the top of the child a solenoid valve work, which sub 2 solenoid valve work while achieving rapid ejection.
A basic thermodynamic properties of hydraulic components
         The basic hydraulic components are divided into three kinds: capacitive element, resistive elements, emotional elements. Internal capacitive element hydraulic cavity, internal resistive element is not plenum, all hydraulic components by one or more of the basic hydraulic components. Hydraulic cylinders which are capacitive components, hydraulic valves are resistive elements.
2 AMESim simulation
         With the development of computer technology, simulation technology has been evolving, simulation technology to improve the level of scientific research and shorten the research cycle, reduce research costs and risks, and promote the integration of different areas, accelerating the research results into productivity process.
         Preferred applications AMESim simulation software for hydraulic systems, verify whether it is feasible to improve the program. Imagine AMESim is the first by the French in 1995, the company launched a complex system modeling and simulation platform for multi-disciplinary fields. 150 icons and intuitive multi-AMESim provides users with a time-domain simulation modeling environment, you can use the existing model and (or) the establishment of a new sub-model elements required to build the optimal design of the actual prototype, using easily recognizable standard port Block Diagram, user-friendly application to establish a specific instance of a complex system and user needs, you can modify the model and simulation parameters, steady-state and dynamic simulation, and analysis of simulation results plotted, more friendly interface, very easy to operate. AMESim allows users to with its friendly, practical application-oriented programs, research dynamics of any component or circuit. This conceptual model library can be achieved, while the model library can be customized to continuously upgrade and improve.
2.1 AMESim system modeling
         Construction of vertical injection molding machine before the top mold improvements and improved system in AMESim draft mode (SketchMode) next. One common mechanical, hydraulic components and sensors section called directly by AMESim hydraulic components and mechanical components library.
         Parameters of hydraulic components and mechanical parts in the parameter mode (ParameterMode) the set: pump displacement 100mL / r; valve opening pressure of 15MPa; the top of the cylinder stroke 0.6m; the top of the cylinder piston rod diameter 35mm, the top of the cylinder bore 60mm, load 2500N; solenoid valve oil inlet flow 1L / min; the length of the tubing set according to the actual situation of vertical injection molding machine, pipe wall thickness of 3mm, hose elastic modulus 2.06 × 105MPa, the wall thickness of 5mm, the inner diameter is set for 15mm; the other parameters remain the default.
2.2 Simulation
         System model simulation time is set to 1s, velocity improved system before that the top of the hydraulic cylinder piston rod ejection speed simulation curve. It can be seen: the rod in uniform motion after t = 0.1s, the velocity of 0.1m / s. Vertical injection molding machine after the ejection lever to improve top speed mode simulation curve, then the maximum flow rate of two valves set to 0.7L / min, can be seen: the rod at t = 0.3s after a system of uniform motion, velocity is 0.18m / s. Through the analysis we can see that the improved speed of the piston rod to improve the speed of 1.8 times before.
         The improved system of two throttle maximum flow down to 0.1L / min, at this time the ejection lever velocity of 0.15m / s, indicating that the flow rate by adjusting the throttle valve to control the movement of the hydraulic cylinder speed. The maximum flow rate is adjusted to a throttle of 0.7L / min, the right of the solenoid valve 2 after power failure, the movement speed of the ejection lever is about 0.092m / s. Because of the relative energy loss is slightly above normal after a single valve solenoid valve in parallel, so the speed of a single valve using the improved relative improvement before slow 0.008m / s. The above results can be seen: the control solenoid valve through power outages, improved system can achieve two speed, and by adjusting the throttle valve can be controlled to achieve the speed of the hydraulic cylinder.
3 vertical injection molding machine to improve test
         Improvement of vertical injection molding machine, test verification by injection 500mL bottles preforms. Materials used PET plastic bottle outside diameter 200-0.35mm, bottom SR10mm, wall thickness of 3mm, preforms high 90mm. Hot runner mold structure, automatic ejection structure, injection pressure a mold cavity 12 40 ~ 50MPa.
         In order to ensure that the product is not damaged stripping, stripping at the top of the speed of the product to be slow, but when you can accelerate the speed of the product from the mold, putting the speed of return can be accelerated. However, the ejection mechanism generally vertical injection molding machine using only one set of hydraulic neutron circuit, when the speed of the product from the mold after or the same, the speed of the return is also constant.
         Two sets of hydraulic oil passage of neutrons will now be parallel with the front oil passage demold time when compared to the unmodified work simultaneously two groups of passage. Slow at the top of the product using a set of hydraulic oil, when the product from the mold, the oil began to work in parallel to achieve rapid movement, when the oil return line is also used in parallel to achieve rewind.
3.2 two cylinder deformation amount
         In the ANSYS environment modeling, elastic modulus is set to 2.6 × 1011, Poisson's ratio is set to 0.3, D1 = 0.38mm; DW1 = 0.47mm, on the model meshing constraint imposed on the whole cylinder ends in applying the internal cylinder p = 1.25 × 1.7313 × 42 × 106N / m2 uniform pressure load.
4. Conclusion
         MATLAB is applied to the design of large-bore column work, the work is summarized as follows: (1) describes the structural characteristics of large-bore column and application principles covering hydraulic holder; and (2) analysis of the double telescopic columns, etc. under load, the working pressure of the piston chamber characteristics determine the cylinder operating pressure and the use of high flow valve theoretical basis; (3) the use of MATLAB programming, variable parameters checking cylinder pressure and burst pressure limit is calculated process; (4) application of ANSYS on the cylinder tube deformation of the finite element analysis. The method described in this paper can be used for the entire process of complex product design.

【Return】