Either hydraulic or electric injection molding machine, the movement will have all in the injection molding process pressure. Proper control of the required pressure to produce quality finished. Pressure regulation and metering system in the hydraulic injection molding machine, all the movements performed by the responsible operation of oil:http://www.prmindustry.com/Abstract...Articles section A plasticizing stage rotary screw.
The two slide forehearth (nozzle close to the sprue bushing).
Injection and holding pressure during radio feed screw axial movement.
4 substrate closed injection rod or piston clamping stroke have been completed until toggle all.
The top five to start the assembly mandrel is introduced to the top of the parts.
In the full voltage on all sports with the implementation of a permanent magnet brushless synchronous motor. The rotational motion is transformed into linear motion by the machine tool industry has been using a ball bearing screw. The efficiency of the entire process depends in part on the plastination process in which the screw play a crucial role in Mitsubishi latest solutions in the production of the whole motor process, including a filling feed screw (threaded hold roller) and one with a screw tip of the mixing components. Thus, to maximize enhanced plasticizing capacity and mixing effect, shorten the screw length to achieve high-speed operation.
The screw must ensure that the materials melting and homogenization. This process can be by means of back pressure adjusted to avoid overheating. Mixing components can not generate excessive velocity, otherwise it may cause degradation of the polymer. Each polymer has a different maximum flow rate, if you exceed this limit, the molecule is stretched, the phenomenon of the polymer main strand breaks. However, the focus remains on the forward axial movement of the screw in the injection and holding pressure process. The subsequent cooling process, including the inherent stress tolerance and warpage and other aspects important to ensure product quality. It all decided by the quality of the mold, to ensure the effective closed-loop temperature control for optimizing the cooling forehearth, especially. The system is completely independent and does not interfere with mechanical adjustment. Closed mold and the ejector mold movement must be precise and efficient. Usually the velocity profile in order to ensure accurate close to the moving parts. Contact to maintain power adjustable. Therefore conclude that, under the premise does not consider energy consumption and mechanical reliability, the same additional conditions (such as the quality of the mold), product quality is mainly determined by the stage of the forward movement of the control screw the system. , This adjustment is achieved by detecting the hydraulic and hydraulic injection molding machine. Specifically, oil pressure through the control panel to activate a valve, the fluid by the manipulator, and to regulate and release.
The injection speed control, including the open-loop control, semi-closed loop control and closed-loop control options. Open-loop system relies on a shared proportional valve. The proportion of tension imposed on the proportion of fluid required, so that the fluid pressure in the injection barrel injection screw to the speed of movement to a certain former. Semi-closed loop system uses a closed-loop proportional valve. Closed loop location in the closed mouth, closed mouth by the movement within the valve to control the oil flow ratio. Closed-loop system is closed when the screw translation speed. Closed-loop system using a speed sensor (usually a potentiometer type), timing detection tension decreased. Proportional valve outflow of fuel through regulation, can compensate for the speed deviation. The closed-loop control rely on one of the special electronic components integrated with the machine. Closed loop pressure control in the injection and packing stages to ensure a uniform pressure, as well as ensure that the back pressure uniform in each cycle. Proportional valve to adjust the detected pressure value, depending on the value of the set pressure deviation compensation. In general, hydraulic monitoring, however, the probe nozzle or in the mold cavity melt pressure is another effective method. A more reliable program management by reading the pressure readings of the nozzle or cavity on the proportional valve. Increase the temperature probe, pressure probe on the basis of particularly conducive to the process management. Understanding of the material can withstand pressure, but also help to predict the actual weight of the molding and size according to the set pressure and temperature conditions. In fact, by changing the value of the holding pressure can be more material into cavity in order to reduce the contraction of parts to meet the design tolerances (including the default injection contraction).
Close to the melting conditions, the semi-crystalline polymer showing a great deal of specific volume change. In this regard, over the filling does not hinder parts ejection.
Hydraulic equipment and the quantity and material pressure regulator
The average hydraulic pressure generated by the centrifugal pumps up to 140 bar, this pressure is particularly suitable for injection molding. In various stages of the cycle, requiring significantly lower, in addition to the need to quickly plasticizing certain circumstances (for example: Note of PET stretch blow one-step injection molding machines) require a higher
In order to reduce energy consumption, can be used in discharging the peak of the variable displacement pump and accumulator tank. The fixed displacement pump to move the same amount of fuel in each rotation, so the pump selection by a specified period of time required to move the oil. Three-phase motor speed generally is 1440 rev / min, usually fitted with twin pumps. Only in the plasticizing process (power up to 100%), pump utilization to reach the maximum. Halt the process, the machinery does not require energy consumption, even if it takes, but also in the case of power loss.
All injection molding machines of varying quality and grade of proportional servo valve. Two or more of the proportional valve is installed in the injection press, the purpose is to accurately control the following aspects:
Mold opening speed (two), closed die speed (two), the closed mold safety, injection (3-10), feeding (3-5), inhalation, and the mandrel (two).
Mold pressure, closed mold pressure mold safety, mechanical fixture (barrel or toggle), injection (filling stage a follow-up stage 3-10), inhalation, and anti-pressure (3-5). Screw rotation speed (3-5).
Slide close to the speed (mechanical nozzle close to the speed of the mold fixed half-mold injection liner) and the plunger movement speed (the introduction of top speed) is also adjustable. Auxiliary motor through a weak input signal, the amplified signal (output signal) is sent to the valves, implementation of the regulatory function of the servo valve. In the servo valve, the weak input signal is converted into hydraulic output signals, to improve the form of a pressure drop according to the required discharge requirements. Valve must be tension or general instructions to make the material response of a rapid, reproducible and low hysteresis. In fact, the current research aimed at improving the frequency response, so running on a dialogue between the kilohertz (kHz) frequency of the power equipment (hydraulic side) and electronic equipment. Effective discharge depends on the role of the valve on the degree of polymerization (DP), the oil temperature in the hydraulic lines must be maintained within the range of 45-55 ° C (usually using the closed-loop regulation system), depending on the fluid viscosity and transition depending on the geometric shape of the mouth. Without proper conditioning system in the valve, rising temperatures will melt viscosity decreases; with balanced open threshold, you can increase the feeding amount. Increase the transmission system to discharge oil, means that the injection speed is facilitated. High-tech servo drive valve for precise control, and to basically eliminate the hysteresis, enhanced repeatability of all functions.
PRM Industry is a highly professional Plastic, Rubber and Metal product manufacturing group. We specialize in providing our customers the integrated solutions of plastic, rubber and metal products. With more than 30 years manufacturing experience, we have been doing, and we also own the capabilities to do, is listening to what our customers need and supplying them the best solutions.
No comments:
Post a Comment