Operation elements of vertical injection molding machine in Dongguan

In the plastic processing industry, vertical injection molding machine is one of the largest injection molding equipment, vertical injection molding products production accounts for more than 30% of the total plastic products, its characteristics are easy to produce automation, short production cycle, strong adaptability, high-grade production power. In addition to fluoroplastics, almost all thermoplastics can be selected for molding of this type of equipment. Relay contactor control system is usually used for mould closing, injection, pressure keeping and mould opening of the original injection molding machine. The disordered wiring, poor reliability and low integration of the detection components. In order to make the function of injection molding machine get useful development, the reliability of the production process. This article chooses the microcomputer control system to replace the traditional control line, and then makes the injection molding machine finish the automation.

The operation process of vertical injection molding machine can be roughly divided into: preheating, mold closing, injection, keeping calendering, mold opening, top strike, flash and other processes. These processes are discontinuous production processes that can be controlled by changes in time or direction. In different time or azimuth equipment travel switch or proximity switch, together advocate the CPU timer start timing, if the movement organization arrives at the end of the regular time or the specified position, then trigger the corresponding travel switch or proximity switch, the system is thought that the implementation of the action at that time is over, otherwise stop and defect alarm. Due to the vertical injection molding machine movement process is more, and some actions due to skill requirements, it is necessary to set up multiple azimuth control points, parameter switching. In the time to take care of together, advocate continuous care, the difference between the action at that time, after admitting without error, connect or disconnect the corresponding implementation of the organization, the end of the rules of action. The whole production process through seven procedures, so the system can be controlled in order to automatically end the seven procedures.

Vertical injection molding machine control system hardware scheme according to the control requirements of the system function, contact the rich hardware cost of microcontroller, this system uses MCS-51 series 8031 chip as the central processor, peripheral expansion of a piece of RAM (6264) and a piece of EPROM (2764). In addition to the roots of the MCU, the system includes parallel interface 8255, ADC1200, and 6 digit 8 segment digital flash.

The software scheme system of the vertical injection molding machine mainly consists of the main program, mold subroutine, injection subroutine, calender-preserving subroutine, mold opening subroutine, top strike subroutine, flash, production subroutine. In the software scheme of the system, the mold closing program is controlled by a limit switch, which can be divided into two processes: slow closing and fast closing. The injection process is controlled by the time of handling, in this time, by the solenoid valve to control the size of the oil pump action, in order to control the hydraulic oil system operation. And when keeping calendering, it is also significantly from time control to open mold program. In the open mold, and by the limit switch control, from slow to fast open. Top strike, production planning process, the former by the time control of its handling; The latter is indicated by the switch action. In this way, if the operation of preheating is independent, the entire product production only needs to go through six processes. The control task of the system is to control the automatic end of the six processes.

The time setting of the automatic procedure of the injection molding machine ensures the accurate detection of the action signal on the function, and the end of the action signal is reliable and useful output on the function. The degree of automation of the equipment. Through the transformation and application of the injection molding machine, a better verification has been obtained, which meets the serious secondary action needs of the injection molding machine, and also brings a better market prospect to the vertical injection molding machine.

Vertical injection molding machine is usually composed of injection system, mold closing system, hydraulic transmission system, electrical control system, lubrication system, heating and cooling system, safety monitoring system, etc. 1 (1) the effect of injection system injection system: injection system is one of the most important components of injection molding machine, usually there are plunger type, screw type, screw pre-plastic plunger injection type three primary methods. The screw type was the most widely used at that time. The effect is that in one cycle of the injection machine, a certain amount of plastic can be heated and plasticized in a regular period of time, and the molten plastic can be written into the mold cavity through a screw at a certain pressure and speed.

The quality of injection molding products depends on the control of injection molding machine injection process skill parameters, including the input variables of the analog method, such as the temperature of each section of the cylinder, polymer melt temperature, screw temperature, mold temperature, injection system pressure, screw speed, etc. Input variables of the digital measurement method, such as the direction of the screw exit connection, the direction of the needle seat, the forward and backward movement of the template, and the overstroke, etc. The injection molding machine system after the use of PLC skills to overcome the defects of the traditional open-loop control method, the end of closed-loop control, so that the PLC control method than the traditional method of anti-interference ability and control precision has a great extent of progress. Can not only switch logic control, also can be combined with analog (such as temperature, pressure, flow, speed, etc.) of closed-loop control. Relying on the keyboard and LCD or digital use ladder diagram to end the control process. There are three kinds of programming methods of ladder diagram: roots instruction scheme; Step instruction scheme; Shift instruction scheme. Flash, can set or correct the skill process parameters, and has an early warning system and defect flash indicator light to monitor the production process, and then greatly advance the whole machine function. The PLC control system transformation cost is less, the construction period is short, the system reliability, safety has been significant progress, has certain implementation and application value.