TWM550216U - Control system for injection molding machine and control card thereof - Google Patents

Description

Control system for injection machine and its control card

This creation relates to an injection molding apparatus, and more particularly to a control system and a control card capable of achieving high speed and precision injection molding.

The general injection molding equipment is commonly known as an injection machine or an injection molding machine, which is a plastic molding equipment, which uses a molding die to make thermoplastic or thermosetting plastic into various shapes of plastic products. The existing injection molding equipment is provided with a control system for automatically controlling the injection molding equipment. Among them, whether the temperature and density of the entire plastic material change process is strictly controlled, which will affect the dimensional stability and warpage of the product.

As shown in Fig. 1, the conventional injection molding apparatus 1 includes, in addition to the injection machine 10, other auxiliary machines 11, for example, a take-out machine, a chiller, a mold temperature machine, a hot runner, a dryer, and a package. The machine, the trainer, the dehumidifier, etc., the injection molding apparatus 1 is required to be equipped with a control system to monitor the working state of the injection machine table 10 and other auxiliary machines 11, and when the working state of the injection molding apparatus 1 does not meet the pre-operation When the parameter standard is set, the control system adjusts the injection molding apparatus 1, so that the control system can be regarded as the core coordination system of the injection molding apparatus 1 to coordinate and control the injection molding apparatus 1 to accurately complete the injection operation.

On the other hand, the control system processes the melting and injection of plastic During the forming process, all control processes are processed through a single central processing unit (CPU) in a single controller, and the central processing unit also converts the signals from the thermocouples of the individual tubes into temperature readings. In order to control the heating system, and convert the potential meter signal of the injection, switch mode and thimble into a position digital signal, to switch the position of each action and the change of pressure and speed, the processing and control item of the central processing unit A lot of it, making it slow to process, and not easy to improve accuracy.

With the development of technology, the precision of the injection molded product and the injection molding speed are becoming higher and higher, and the injection molding of light and thin short objects such as a minute resin lens, a component of a mobile phone case, and a protective case of a large liquid crystal screen are performed. At the time, the precision of the control is much higher than that of general household products, so the requirements for the reaction speed and reaction accuracy of the overall control system are more.

However, at present, the best control system for the injection machine has many processing and control items in the central processing unit, including screw rotation (melting material), injection, pressure holding after ejection, loosening action, switching die and tightening die, Product ejection (the above data have pressure, speed, switching position, action time and other data), temperature monitoring refers to heating, neutron action, human-machine interface (HMI) display and memory of molding parameters, each mode A large amount of data such as data records, alarm records, parameter modification records, etc., and the software design is periodically operated, so the control system completes a cycle period of about 1 to 2 milliseconds, or even longer, resulting in a cycle response time of each control. It is slow, so it is difficult to meet the needs of today's high-speed injection process.

Furthermore, the position of the control system is transmitted from 0 to 10V. The value is therefore susceptible to interference, resulting in a reading and display accuracy of only 0.1 mm, which makes it difficult to improve the control accuracy, and thus is difficult to meet the current demand for high precision injection processes.

In addition, the hydraulic power circuit is mostly driven by a proportional pressure valve and a proportional flow valve (or the oil pump servo motor) to control the increase and decrease of the oil intake of the cylinder, but for the fast-moving machine, due to the lack of rapid deceleration and stop The brake function requires the use of a fast proportional directional valve or servo valve for precise control.

Therefore, how to solve the various problems of the above-mentioned prior art is an urgent problem to be solved in the industry.

In order to solve the above problems of the prior art, the present invention provides a control card for an injection machine, which comprises: a first closed loop control loop for performing injection control of the injection machine; and a second closed loop control loop for use. The switch mode control or turntable control is performed on the injection machine; and the memory is used for the controller of the injection machine to transmit data about the closed loop control to the memory by means of digital communication.

The present invention also provides a control system for an injection machine, comprising: a controller; and the aforementioned control card, which is transmitted and connected in a digital communication manner.

In the foregoing control system and its control card, the control card performs circuit layout by using a proportional integral differential control method.

In the foregoing control system and its control card, the digital communication system is a controller area network or an Ethernet control automation technology.

In the aforementioned control system and its control card, the control card has a pressure signal receiver for signally connecting the pressure sensor of the injector.

In the foregoing control system and its control card, the control card has a register for connecting a position ruler.

In the aforementioned control system and its control card, the control card has a digital signal processor to generate a vibration signal.

In the foregoing control system and its control card, the control card has a back-forwarding waver to feed back the position of the turntable of the current injector.

It can be seen from the above that the control system of the present invention and its control card are mainly designed as a high-speed precision closed-loop control card by defining the functions of various actions related to monitoring and shooting quality in the conventional controller to define a high-speed independent operation. The central processing unit (CPU) can reduce the processing capacity of the controller to increase its processing speed. Therefore, compared with the control system of the prior art, the control card of the present invention can be synchronized with the controller. Handle all control information for the injection machine to obtain high-speed and precise injection molding operations.

1‧‧‧Injection molding equipment

10‧‧‧Injection machine

11‧‧‧Auxiliary machine

2‧‧‧Control card

2a‧‧‧First closed loop control loop

2b‧‧‧Second closed loop control loop

20‧‧‧ memory

21‧‧‧ Pressure signal receiver

22‧‧‧Scratch

23‧‧‧Digital signal processing

24‧‧‧Returning wave

25a, 25b‧‧‧ proportional valve

3a‧‧‧Digital input

3b‧‧‧ digital output

4a‧‧‧ Shooting position ruler

4b‧‧‧Switching mold position ruler

5‧‧‧ machine

6‧‧‧ Pressure sensor

7‧‧‧ Turntable position detector

8‧‧‧Control system

9‧‧‧ Controller

A, B‧‧ directive

D‧‧‧ data

1 is a schematic diagram of a control system of a conventional injection molding machine; FIG. 2 is a schematic diagram of a configuration of an embodiment of a control card of the present invention; and FIG. 3 is a schematic diagram of a configuration of an embodiment of the control system of the present invention. .

The implementation of the present invention will be described below by way of specific embodiments. Those skilled in the art can readily appreciate other advantages and functions of the present invention from the disclosure herein.

It is to be understood that the structure, the proportions, the size and the like of the drawings are only used in conjunction with the disclosure of the specification for the understanding and reading of those skilled in the art, and are not intended to limit the implementation of the present invention. The conditions are limited, so it is not technically meaningful. Any modification of the structure, change of the proportional relationship or adjustment of the size should remain in this book without affecting the effectiveness and the purpose of the creation. The technical content revealed by the creation can be covered. In the meantime, the terms "upper" and "one" as used in this specification are for convenience of description only, and are not intended to limit the scope of implementation of the creation, and the relative relationship is changed or adjusted. Under the technical content of no substantive change, it is also regarded as the scope of implementation of this creation.

The second and third figures are schematic diagrams of the configuration of the control system for the injection machine and its control card.

As shown in Figures 2 and 3, the control system 8 of the injector includes a controller 9 and at least one control card 2, and the control card 2 utilizes a proportional-integral-derivative (referred to as PID). The control mode performs circuit layout, and includes: a first closed loop control loop 2a for performing injection control of the machine 5, and a second closed loop control loop 2h for performing switch mode control of the machine 5, wherein the machine The stage 5 is defined as an injection machine of the injection machine and an auxiliary machine thereof, for example, a take-out machine, a chiller, a mold temperature machine, a hot runner, a dryer, a packaging machine, a trainer, a dehumidifier, and the like.

In this embodiment, the control card 2 is configured with a memory 20 for the controller 9 to utilize digital communication, for example, Controller Area Network (CAN) or Ethernet control automation. The technology (Ether Control Automation Technology, Ether CAT for short) transmits the data D about the closed-loop control set by the operator to the memory 20, wherein the data D includes the settings related to the emission and the settings related to the switch mode.

The emission related setting system may include: a speed requirement for each segment, a switching position of each segment, a pressure limit for each segment, a maximum velocity of the injection device, a first slope (Ramp) PID, and each segment. Pressure holding pressure, time of each holding pressure, form of each holding pressure, second slope PID, pressure of back pressure of each section, switching position of back pressure of each section, third slope PID, stocking After the completion of the retraction speed, the retracted position, the fourth slope PID, and other engagement-related action positions (for example, using the digital input 3a and the digital output 3b of the control card 2).

The switch mode related configuration includes: a switch mode related setting (a limit pressure of each switch mode, a speed of each switch mode, a switching position of each switch mode), a fifth slope PID, and a low voltage protection section. Through the necessary time, other coordination actions related to the switch mode.

Furthermore, the control card 2 is also provided with a pressure signal receiver 21, a register 22 connecting the injection position gauge 4a and the switch mode position 4b, and at least one digital signal processing 23.

The pressure signal receiver 21 is connected to various pressure sensors 6 of the injection machine, for example, a pressure sensor for injecting a cylinder, and a mold oil. A pressure sensor of the cylinder, or other pressure sensor such as a cavity pressure sensor.

The injection and switch mode position gauges 4a, 4b are in accordance with the SSI standard and adopt a digital transmission type position scale with a reading accuracy of 0.01 mm and a data update rate of 15 KHz, and are the current highest precision and the fastest reaction rate. In order to transmit and update the data in the register 22 at any time, on the one hand, the central processing unit of the control card 2 operates quickly and accurately, and on the other hand, the latest injection and switching modes are also on time via digital communication. The signal is passed to the controller 9 of the injector to cause the controller 9 to perform other controls (e.g., control operations that do not require precise operation, or control operations that are not controlled by the control card 2).

The digital signal processor 23 introduces a vibration signal into the oil pressure driving control of the injection machine, and maintains the spindle of the high speed proportional directional valve in a vibrating state to generate an oil film, and the mandrel is at any time. The dynamic friction state causes a small control signal to also cause the proportional valves 25a, 25b of the injector to reach the desired position quickly and accurately.

Moreover, the injection machine may have an amplifier board for driving the injection control proportional valve 25a and the switch mode control proportional valve 25b, but for using a linear variable differential transformer (LVDT) The position of the proportional valve that does not have a built-in drive amplifier plate, the proportional valve amplifying plate can be inserted at the output position to obtain the drive function of the proportional valve, for example, by the power supply. The printed circuit board of the card 2 and the general proportional valve amplifying board can be powered by a DC24V power supply. Specifically, as shown in FIG. 3, the proportional valve amplification plate transmits Two commands A, B are sent to the machine 5, one of which is the LVDT position feedback, and the other command B is the LVDT position feedback and the proportional valve opening control.

In addition, if a proportional valve control circuit of the control card 2 is selected as the rotary rotation control of the two-color machine, a corresponding rotary disk (such as the rotary position detector 7) or the gear is configured to return the wave repeater 24 to feedback the position of the current turntable. The data is stored in the register 22 for accurate deceleration and stop functions. Specifically, if the injection machine is a two-color machine, at least two closed-loop control cards 2 are included, wherein one closed-loop control card 2 performs injection control and switch mode control of one of the injection mounts, and the other closed-loop control card 2 performs another Injection control of one injection stand and control of the mold base turntable.

Therefore, the control system 8 of the present invention is to add at least one high-speed precision closed-loop control card 2 to the controller 9 of the general injection machine to define a high-speed independent central processing unit (CPU) whose dedicated closed-loop monitoring is related to the quality of the injection. Each action in a certain period of time, running and processing the set speed, pressure, position, time and other conditions all the time, and the faster the cycle, about 15 cycles per millisecond (ms), so that it can be achieved The variation value is relatively reduced, and the interference is also reduced on the detected parameters (such as position, pressure, etc.), or high-order digitized on its components and quickly provided to the register 22 (accuracy of display and control position) Up to 0.01mm), the central processing unit can be directly digitally aligned, minimizing the variability of each switching, and achieving the highest stability and repeatability of pressure and speed during actuation.

Furthermore, the hardware design of the high-speed precision closed-loop control card 2 of this creation considers the requirements of industrial application, the development of software application functions, and more functions. Selective and suitable for a variety of machine applications, each control card 2 can be installed with two high-speed proportional directional valves, hydraulic servo proportional valves or hydraulic servo valves for high-speed closed-loop control of two parts, namely the first The closed loop control loop 2a and the second closed loop control loop 2b.

In summary, the control system and its control card of the present invention have the following advantages:

1. The injection control and the switch mode control are independently set on the control card 2 from the control system 8 of the injection machine, and the independent central processing unit (CPU) on the control card 2 is required to bear less computational load than the conventional controller. The control period of the injection can be reduced (the conventional controller is 1~2 milliseconds/time, the control card 2 is 0.05~0.06 milliseconds/time), and the error of the control position is reduced (the conventional controller is 0.1mm, the The control card 2 is 0.01 mm), so the weight stability of the injection molded product made by the injection machine of the present control system 8 can be greatly improved (the weight error of the product of the conventional injection machine is 0.3% to 0.5%, The product of the control system 8 of the present invention has a product weight error of 0.01% or less.

2. When the high-speed closed-loop control injection is performed by the independent central processing unit (CPU) of the control card 2, it can ensure that each speed is the same and stable, and the high-speed low speed can achieve the high repeatability of the deceleration via the hydraulic brake function. Accurate switching and stopping position, and the injection control valve can be used for closed-loop control of holding pressure, multi-stage storage and stable back pressure, and retracting and retracting action.

3. The injection closed loop control loop (first closed loop control loop 2a) and the switch mode closed loop control loop (second closed loop control loop 2b) are disposed on the same closed loop control card 2, which can shorten the reaction time to ensure that the injection reaches the set position. When the time is set, the mold closing action can be performed immediately.

Fourth, the use of high-speed proportional directional valves (ie proportional valves 25a, 25b), when the injection speed needs to be increased from 100mm / sec to 600mm / sec, even at higher speeds, high-speed to low-speed operation by hydraulic brake function, It can achieve high repeatability of deceleration and ensure product stability.

5. Due to the high precision of high-speed injection, it is possible to perform compression molding on the surface of the product, such as re-compression of the paint, the leather surface of the traffic equipment, or the in-mold paste of the flocked fabric.

Sixth, even if the speed of the switch mode of the in-mold work is accelerated, it can be accurately positioned.

7. The two-color machine uses two closed-loop control cards 2 to control the two-color high-speed precision injection process, which not only makes the turntable movement smooth and smooth, but also can accurately position the turntable and accurately position the switch mode.

8. After the injection operation, the mold is opened for foaming, and the position of the pull-opening can be precisely controlled to achieve product consistency.

9. When the control point of the gas-assisted injection molding is controlled by the control card 2, the yield of the finished product is greatly improved (the yield of the finished product of the injection machine is 70%, and the injection machine of the control system 8 of the present invention is used. Product yield is 98% or more).

10. Using the output point of the control card 2 to control the opening of the gate of the sequence valve can greatly improve the stability of each product.

The above embodiments are intended to illustrate the principles of the present invention and its effects, and are not intended to limit the present invention. Anyone who is familiar with this skill can repair the above embodiments without violating the spirit and scope of this creation. change. Therefore, the scope of protection of this creation should be as listed in the scope of patent application described later.

2‧‧‧Control card

2a‧‧‧First closed loop control loop

2b‧‧‧Second closed loop control loop

20‧‧‧ memory

21‧‧‧ Pressure signal receiver

22‧‧‧Scratch

23‧‧‧Digital signal processing

24‧‧‧Returning wave

25a, 25b‧‧‧ proportional valve

3a‧‧‧Digital input

3b‧‧‧ digital output

4a‧‧‧ Shooting position ruler

4b‧‧‧Switching mold position ruler

5‧‧‧ machine

6‧‧‧ Pressure sensor

7‧‧‧ Turntable position detector

8‧‧‧Control system

9‧‧‧ Controller

D‧‧‧ data

Claims (10)

A control card for an injection machine includes: a first closed loop control loop for performing injection control of the injector; and a second closed loop control loop for performing switch mode control or turntable control of the injector; The memory is connected to the first and second closed loop control loops, and the controller of the injector transmits data about the closed loop control to the memory by means of digital communication. For example, the control card described in the first item of the patent scope uses a proportional integral differential control method for circuit layout. The control card of claim 1, which has a pressure signal receiver, and the injector has a pressure sensor for connecting the pressure signal receiver signal to the pressure sensor of the injector. The control card of claim 1, which has a register for connecting a position ruler. The control card of claim 1, wherein the control card has a back-forwarding wave, and the injector has a turntable to return the forward-forwarding wave to the position of the turntable of the current injector. A control system for an injection machine, comprising: a controller; and a control card according to claim 1 of the patent application, which is connected and connected by means of digital communication. The control system of claim 6, wherein the control The card system uses the proportional integral differential control method for circuit layout. The control system of claim 6, wherein the control card has a pressure signal receiver, and the injector has a pressure sensor to connect the pressure signal receiver signal to the pressure sense of the injector Detector. The control system of claim 6, wherein the control card has a register for connecting a position gauge. The control system of claim 6, wherein the control card has a back-forwarding wave, and the injector has a turntable to cause the back-forwarding wave to feed back the position of the turntable of the current injector.