JPH04158019A - Control method for electric injection molding machine using induction type AC servo motor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field J] The present invention enables each process of mold opening/closing, ejection, injection, and plasticization to be performed by driving an induction type AC servo motor (hereinafter simply referred to as "motor"). The present invention relates to a method of controlling an electric injection molding machine.

[Prior Art] In a conventional electric injection molding machine, a predetermined current, which is an initial excitation current that allows each motor to exert its maximum force, is always supplied to each motor.

[Problems to be Solved by the Invention] In the above-mentioned conventional technology, an initial excitation current is always applied to each motor so that the maximum torque can be immediately produced even when the maximum force of each motor is not required. The problem is that power is consumed.

The present invention has been made in view of the problems of the above-mentioned conventional techniques, and is an inductive type A that can reduce power consumption.
An object of the present invention is to provide a method for controlling an electric injection molding machine using a C servo motor.

[Means for Solving the Problems] In order to achieve the above object, a method for controlling an electric injection molding machine using an induction type AC servo motor according to the present invention is as follows: In an electric injection molding machine driven by an AC servo motor, the mold opening/closing process is from the time the mold opens until just before the mold closes, and the ejecting process is from the time the ejector completes its return to just before the start of ejecting. After weighing the molding material, the initial excitation current of the induction type AC servo motor is reduced from the end of suckback until just before the start of injection, and in the plasticizing process from the end of plasticization until just before the start of the next plasticization.

In this case, it is desirable to reduce the initial excitation current of each induction type AC servo motor to a range of 80 to 30% of the respective predetermined current.

[For use] In the mold opening/closing process, from the completion of mold opening until just before the start of mold closing; in the ejection process, from the completion of the return of the ejector to just before the start of ejection; in the injection process, after measuring the molding material, from the end of suckback until injection In the plasticizing process, from the end of plasticization until just before the start of the next plasticization, each motor does not perform mechanical work and does not need to rotate. For this reason, the initial movement iii! Even if the current is reduced to reduce power consumption, molding can be performed without any problems.
By reducing the initial excitation current, power consumption can be reduced.

[Example] Examples will be described based on the drawings.

In FIG. 1, a movable platen 2 of a mold clamping device 1 is guided by a plurality of tie bars 6 that connect a fixed platen 4 fixed on a bed 3 and a housing 5, and reciprocates in the left-right direction in the figure, which is the axial direction of the movable platen 2. It is arranged so that it can be moved freely. The movable platen 2 is provided with an ejection device 7 having an ejection servo motor 8, and the ejection servo motor 8 is supplied with an initial excitation current from an ejection servo amplifier.

Furthermore, a toggle mechanism (not shown) is interposed between the housing 5 and the movable platen 2, and the toggle mechanism is driven by a mold opening/closing servo motor 11 provided via a ball screw (not shown), two pulleys 9, and a timing belt 1o. The mold opening/closing servo motor 11 is configured to expand and contract to open/close the mold by the driving force of the mold opening/closing servo amplifier 21.
An initial excitation current is given.

On the other hand, a screw 13 is fitted into a cylinder 14 of an injection device 12, which is provided on the right side of the mold clamping device 1 in opposition to the mold clamping device 1, and the screw 13 is inserted in the axial direction, which is the horizontal direction in the diagram. It is configured to be able to freely reciprocate (forward and backward) and rotate freely. The driving force for reciprocating the screw 13 is provided by two boots 17 and a timing belt 18.
The driving force for rotation of the screw 13 is applied from the injection servo motor 15 via the plasticizing servo motor 16, and the injection servo motor 15
The plasticizing servo motor 16 is supplied with an initial excitation current from the injection servo amplifier 23 and the plasticizing servo amplifier 24, respectively.

The configuration described above can be applied to a known electric injection molding machine.

In addition, a mold opening/closing servo amplifier 21, an ejection servo amplifier 2
2. Injection servo amplifier 23 and plasticizing servo amplifier 2
4 is entirely controlled by a controller 20. As the controller 20, a known hardware configuration that is configured to perform a control method described later by software can be applied.

Next, a control method in this embodiment will be explained.

In the mold opening/closing process, when the movable platen 2 is stopped at the mold opening position, the mold opening/closing servo motor 11 is also stopped.
Since it is not necessary to exert the maximum force, the controller 20 controls the mold so that the initial excitation current of the mold opening/closing servo motor 11 is reduced to 80 to 30% of its predetermined current to the extent that the movable platen 2 does not move due to external causes. A command is sent to the opening/closing servo amplifier 21. Then, just before closing the mold (several seconds), the controller 20 sends a command to the mold opening/closing servo amplifier 21 to apply the predetermined current to the mold opening/closing servo motor 11, and then moves the movable platen 2 in the mold closing direction. Then close the mold.

In the ejecting process, when the ejecting device 7 is stopped at the return position, the ejecting servo motor 8 is also stopped,
Since there is no need to exert its maximum force, the ejection device 7
The controller 20 sends a command to the protruding servo amplifier 22 to reduce the initial excitation current of the protruding servo motor 8 to a range of 80 to 30% of the predetermined current to such an extent that the protruding servo motor 8 does not move due to external causes. Then, just before performing the protrusion (several seconds),
After the controller 20 sends a command to the ejection servo amplifier 22 to apply the predetermined current to the ejection servo motor 8, the ejection device 7 is operated to perform ejection.

In the injection process, when the screw 13 stops moving after the suckback to prevent resin leakage from the nozzle (not shown) of the cylinder 14 after measurement, the injection servo motor 15 is also stopped. Since it is not necessary to exert maximum force, the controller 20 is configured to reduce the initial excitation current of the injection servo motor 15 to a range of 80 to 30% of the predetermined current so that the screw 13 does not move due to the resin pressure in the cylinder 14. sends a command to the injection servo amplifier 23. Then, just before injection (several seconds), the controller 20 sends a command to the injection servo amplifier 23 to apply the predetermined current to the injection servo motor 15.
Injection is performed by advancing the screw 13 to the left in the figure.

In the plasticizing process, when the screw 13 stops rotating, the plasticizing servo motor 16 also stops, and there is no need to exert its maximum force, so the screw 13 is moved by the resin pressure in the cylinder 14. The initial excitation current of the injection servo motor 16 is set to 80 to 80% of its predetermined current to the extent that it does not rotate.
The controller 20 sends a command to the plasticizing servo amplifier 24 to reduce the amount within a range of 30%. Then, just before weighing and plasticizing (several seconds), the controller 20 sends a command to the plasticizing servo amplifier 24 to apply the predetermined current to the plasticizing servo motor 16, and then the screw 13 is rotated and the weighing is carried out. and plasticization.

In the above example, the reason why the initial excitation current of each servo motor was set to fall within the range of 80 to 30% of its predetermined current is that below 30%, it will cause problems in driving each process, and above 80%, This is because the effect of reducing power consumption is not so great.

[Effect of the invention] Since the present invention is configured as described above, the mold opening/closing,
It is possible to reduce the wasteful power consumption of each motor for obtaining the driving force for each of the ejection, injection, and plasticization steps, resulting in an effect that the cost required for operation can be lowered.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the configuration of an electric injection molding machine applied to an embodiment of the present invention. 1... mold clamping device, 2... movable platen, 3...
- Bed, 4... Fixed plate, 5... Housing, 6... Tie bar, 7... Ejection device, 8... Ejection servo motor 9... Pulley, 10... Timing belt, 11・
... Mold opening/closing servo motor, 12... Injection device, 13.
...Screw, 14...Cylinder, 15.
...Injection servo motor, ]6...Plasticizing servo motor 17...Pulley, 18...Timing belt, 20...Controller, 21...Mold opening/closing servo amplifier 22...Protrusion servo amplifier, 23・
...Injection servo amplifier 24...Plasticizing servo amplifier. Patent applicant: Japan Steel Works, Ltd.

Claims (1)

[Claims] 1. In an electric injection molding machine in which the mold opening/closing, ejection, injection, and plasticizing processes are each driven by an induction type AC servo motor, the mold opening/closing process is performed from the completion of mold opening to just before the mold closing starts. In the ejection process, from the end of the return of the ejector to just before the start of ejection; in the injection process, after measuring the molding material, from the end of suckback to just before the start of injection; in the plasticization process, from the end of plasticization to the start of the next plasticization A method for controlling an electric injection molding machine using an induction type AC servo motor, characterized in that the initial excitation current of the induction type AC servo motor is reduced until immediately before the induction type AC servo motor. 2. The method for controlling an electric injection molding machine using an induction type AC servo motor according to claim 1, wherein the initial excitation current of each induction type AC servo motor is reduced to a range of 80 to 30% of the respective predetermined current.