JPH08318545A - Method and apparatus for controlling injection device of electromotive injection molding machine - Google Patents

Abstract

PURPOSE: To prevent the abrasion of a guide pin or a guide bush at a time of the opening and closing of a mold by controlling the actual nozzle touch force pressing an injection nozzle to the mold so as to make the same equal to preset nozzle touch force. CONSTITUTION: When an injection device 14 retreats to a predetermined retreat position, the set retreat position stored in a controller 50 coincides with the actual retreat position outputted from a position detector 46 and the switching device 48 to which a command signal is outputted from the controller 50 opens a power circuit to cut off the power to an electromotor 40. By this constitution, the injection device 14 stops at a predetermined retreat position to correct the set nozzle touch force set to the controller 50 to a value slightly larger than that up to now if a resin leak is generated from an injection nozzle 16 during molding processing. An operator 54 again performs operation on the basis of the corrected set nozzle touch force and calculates a corrected set stroke to send the same to a memory device 56. The memory device 56 renews memory data to output the same to a comparator 58.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection device movement control device for an electric injection molding machine, and more particularly, to moving an injection device for an electric injection molding machine using a motor as a drive source for moving the injection device. Regarding the control device.

[0002]

2. Description of the Related Art A conventional injection device moving device for an electric injection molding machine, for example, as shown in JP-A-64-36423, drives an electric motor (DC motor or AC motor) when necessary, The injection device is advanced from a predetermined retracted position to a nozzle touch position where the nozzle opening of the injection nozzle contacts the mold side sprue bush, and a predetermined nozzle touch force is applied to the injection nozzle, for example, via a spring member. In this state, the subsequent injection pressure-holding step is performed, and after the step is completed, for example, the spring member is extended to reduce the spring force to 0, the injection device is retracted, and the injection is performed again at the predetermined retracted position. It is configured to shut down the device. Then, in order to reliably prevent resin leakage from the injection nozzle during the injection pressure-holding step, the nozzle touch force is generally set to a larger constant value than necessary in consideration of a margin. is there.

[0003]

However, since the nozzle touch force is set larger than necessary in the injection device moving device of the conventional electric injection molding machine as described above, the injection force is increased when the nozzle touch force is applied. There is a problem that the nozzle and the sprue bush on the mold side may be damaged. In addition, since the mold is subjected to bending stress due to a large nozzle touch force, the guide pin and the guide bush may be worn or damaged when the mold is opened and closed. The present invention aims to solve such problems.

[0004]

According to the present invention, the nozzle touch force can be arbitrarily changed to set a minimum nozzle touch force that does not cause resin leakage from an injection nozzle, and an arbitrary nozzle touch force can be set during a molding process. The above problem is solved by generating the nozzle touch force at a timing. That is, in the injection device movement control method for the electric injection molding machine according to claim 1 of the present invention, when the injection device having the injection nozzle is moved in a direction approaching the mold,
When the injection device is driven by the electric motor via the power transmission mechanism and the spring, and when the injection device is moved in the direction away from the mold, the injection device is driven by the electric motor via the power transmission mechanism and without the spring. Using the injection device moving device of the electric injection molding machine configured to drive the motor, the electric motor is adjusted so that the actual nozzle touch force that presses the injection nozzle against the mold becomes equal to the preset nozzle touch force. It is characterized in that the deflection amount of the spring is adjusted by controlling. Further, the injection device movement control device of the electric injection molding machine according to claim 2 has an electric motor (40), a power transmission mechanism (44) connected thereto, a power transmission mechanism (44) and an injection nozzle (16). And a spring (24) disposed between the injection device (14) and the injection device (14), and the injection device (14) is mounted on the mold (18) according to the rotation direction of the electric motor (40). The injection device (14) can be moved toward and away from the mold (1).
8) When moving in the direction of approaching 8),
0) power transmission mechanism (44) and spring (2)
4), the injection device (14) is driven, while the injection device (14) is moved in the direction away from the mold (18), the motor (40) is used to drive the power transmission mechanism (4).
Position detection capable of detecting the deflection amount of the spring (24), which is configured to drive the injection device (14) via the spring (24) and via the spring (24). (46), a setting device (52) for setting the nozzle touch force for pressing the injection nozzle (16) against the mold (18), and a set deflection amount of the spring (24) corresponding to the set nozzle touch force. A computing unit (54) for computing, a storage unit (56) for storing the computed set deflection amount, a deflection amount output from the storage unit (56), and a position detector (46) It is characterized by having a comparator (58) for comparing the actual amount of deflection and a controller (50) for controlling the electric motor (40) based on the output from the comparator (58). The third aspect is characterized in that the timing of generating the nozzle touch force is set in the controller (50). The reference numerals in parentheses indicate the corresponding members of the embodiment.

[0005]

In the injection molding, a minimum nozzle touch force is applied so that the resin does not leak from the injection nozzle. By doing so, the mold and the injection nozzle are not damaged when the nozzle is touched, and the guide pin and the guide bush are not worn or damaged when the mold is opened and closed.

[0006]

EXAMPLE FIG. 1 shows an example of the present invention. The mounting plate 10 is fixed to a fixed portion such as a base of the injection molding machine. A slide plate 12 is slidably mounted on the mounting plate 10. An injection device 14 is provided integrally with the slide plate 12. The injection device 14 has an injection nozzle 16 which is integral with the injection device 14, and can inject molten resin from this. The injection device 14 can be slid on the mounting plate 10 in the left-right direction in the figure integrally with the slide plate 12 by being driven by the electric motor 40 via a power transmission mechanism 44 described later. That is, the injection nozzle 16 of the injection device 14
Is movable between a nozzle touch position in contact with the illustrated mold 18 and a retracted position to the right of the nozzle touch position. The slide plate 12 is formed with a spring chamber 20 having a through hole 22 on the wall surface side facing the mold 18. A spring 24 is arranged in the spring chamber 20. A spring receiver 26 is arranged in the spring chamber 20 so as to contact the right end portion of the spring 24 in the figure. A shaft 28 is provided that extends through the through hole 22 and extends into the spring chamber 20. The right end of the shaft 28 in the drawing is connected to the spring receiver 26, and a ball screw 30 is formed on the left end side of the shaft 28, and a ball nut 32 is screwed into the ball screw 30. . A gear 34 is provided integrally with the ball nut 32. A gear 36 is meshed with the gear 34. The right end side of the shaft 38 of the gear 36 in the figure is connected to the electric motor 40, and the left end side of the figure in the figure is the electromagnetic brake 4.
It is connected to 2. The shaft 38, the gear 36, the gear 34, the ball nut 32, the ball screw 30, the shaft 28, and the spring receiver 26 form a power transmission mechanism 44. Electric motor 4
The rotational movement of 0 is converted into a linear movement in the horizontal direction in the figure by the power transmission mechanism 44. That is, the shaft 40, the gear 36, the gear 34,
And the ball nut 32 is rotated, and the ball nut 3
The rotational movement of 2 is converted into the linear movement of the ball screw 30,
The ball screw 30, the shaft 28, and the spring receiver 26 are moved together in the axial direction. When the ball screw 30, the shaft 28, and the spring receiver 26 move in the right direction (retracting position direction) in the drawing, the spring 24 extends from a compressed state (a nozzle touch force generation state) than the illustrated state. Then, after the right end of the spring receiver 26 in the drawing contacts the wall on the right side of the spring chamber 20 in the drawing, the slide plate 12 is pushed rightward in the drawing by the spring receiver 26, so that the slide plate 12 and the injection device are ejected. 14 will move to the right in the figure. At this time, the spring 24 is gradually expanded so that the spring force becomes zero at the retracted position. Further, the ball screw 30, the shaft 28, and the spring receiver 26
Is moved from the retracted position to the left in the drawing (toward the nozzle touch position), the slide plate 12 is pushed to the left in the drawing via the spring 24, so that
2 and the injection device 14 are moved to the left in the drawing. It should be noted that FIG. 1 shows a state where the nozzle touches, but the amount of deflection of the spring 24 is 0, and therefore the nozzle touch force is 0. From this state, as shown in FIG. 2, if the flexure amount of the spring 24 at the time of touching the nozzle is changed from 0 to MAX, the magnitude of the nozzle touch force can be changed accordingly. is there. In addition, when the amount of deflection of the spring 24 is 0,
When a backward force based on the injection pressure is applied to the injection nozzle 16, resin leakage occurs from the injection nozzle 16. Therefore, the deflection amount of the spring 24 is actually a predetermined lower limit value larger than 0 and MAX. It will be decided to a value between and.

A position detector 46 is connected to the ball screw 30. As the position detector 46, a potentiometer, an encoder or the like can be used. The position detector 46 can detect the position of the ball screw 30 in the left-right direction (deflection amount of the spring 24) in the figure. The control panel of the injection molding machine includes a switch 48, a controller 50, a setting device 52,
A calculator 54, a memory 56, and a comparator 58 are provided respectively. The electric motor 40 can be rotated in both forward and reverse directions by being controlled by the controller 50 via the switch 48. Further, the electromagnetic brake 42 includes a controller 50.
The electric motor 40 and the power transmission mechanism 44 can be braked by being directly controlled by. The setting device 52 can set the nozzle touch force to a desired value. That is, in the device of the present invention, as will be described later, it is possible to arbitrarily set the nozzle touch force within the range of the compression force of the spring 24. The calculator 54 can calculate the set stroke amount of the ball screw 30 (that is, the set deflection amount of the spring 24) required to generate the set nozzle touch force set in the setter 52, and the calculated result is obtained. It can be output to the storage device 56. The comparator 58 compares the set stroke amount of the ball screw 30 stored in the storage device 56 with the actual stroke amount of the ball screw 30 detected by the position detector 46, and determines the difference between the two stroke amounts (stroke difference). That is, the difference between the set deflection amount of the spring 24 and the actual deflection amount) is output to the controller 50. The controller 50 controls the switch 4 when the stroke difference from the comparator 58 becomes zero.
It is possible to output a control signal to 8 to cut off the power supply to the electric motor 40. The timing at which the nozzle touch force is generated can also be set in the controller 50. That is, it is possible to generate a predetermined nozzle touch force at a timing required during the molding process.

Next, the operation of this embodiment will be described. The setting unit 52 is set in advance with a minimum nozzle touch force to the extent that resin leakage does not occur from the injection nozzle 16 and the timing of nozzle touch force generation. The magnitude of the nozzle touch force required to prevent the resin from leaking from the injection nozzle 16 varies depending on the viscosity of the resin used, etc., so it is determined by a test, an empirical formula, etc. according to the usage conditions. Further, the controller 50 includes a position detector 46 when the injection device 14 is located at a predetermined retracted position.
The output of is stored as the set backward position. Calculator 54
Calculates the set stroke amount of the ball screw 30 based on the set nozzle touch force set in the setter 52, and outputs the calculated result to the storage device 56. The storage device 56 outputs the stored set stroke amount to the comparator 58. First, the injection device 14 is located at a retracted position on the right side of the drawing with respect to the illustrated position. Next, the injection device 1 is synchronized with the mold clamping operation by the mold clamping device of the injection molding machine.
The moving process of 4 is started. That is, the controller 50 outputs a command signal to the switch 48 based on the stroke difference output from the comparator 58 in a state where the injection device 14 is located in the retracted position to the right of the illustrated position. Due to
The switch 48 closes the power circuit and the electric power is supplied to the electric motor 40. When the electric motor 40 rotates in a predetermined direction, the slide plate 12 and the injection device 14 move leftward in the drawing via the power transmission mechanism 44 and the spring 24, and the injection nozzle 16 moves to the mold 18 as shown in the drawing. Contact. When the electric motor 40 is further rotated from this state, the ball screw 3
0, the shaft 28 and the spring receiver 26 further move to the left in the figure, and the spring 24 is compressed by the spring receiver 26. When the spring 24 is compressed to the position where the set nozzle touch force is generated (the position where the set deflection amount is set), the stroke difference output from the comparator 58 becomes 0, and the controller 50 outputs a signal to the switch 48. Since the switch 48 opens the power circuit to cut off the electric power to the electric motor 40, the electromagnetic brake 42 is actuated by the command signal from the controller 50 and the power transmission mechanism 44 is stopped.
Will remain stopped in that position. Next, controller 5
In response to a command signal from 0, the injection operation is started, the molten resin is injected from the injection device 14 into the mold 18 through the injection nozzle 16, and the subsequent pressure holding step is performed. After the pressure holding process is completed, the switch 48 is activated by a command signal from the controller 50.
, The electric motor 40 rotates in the direction opposite to the predetermined direction, and the ball screw 3 of the power transmission mechanism 44 is rotated.
0, the shaft 28, and the spring receiver 26 move to the right in the drawing to extend the spring 24. In this state, the injection device 14 has not moved yet. When the amount of deflection of the spring 24 becomes zero, the nozzle touch force is released. Further, the ball screw 30, the shaft 28, and the spring receiver 26
Moves to the right in the figure, so that the spring receiver 2
The slide plate 12 is pushed to the right in the figure by 6, and the slide plate 12 and the injection device 14 start to retreat from the illustrated position to the right in the figure. That is, the injection device 14
The reciprocating operation is performed by the electric motor 40 via only the power transmission mechanism 44 (without the spring 24). When the injection device 14 retracts to a predetermined retracted position, the set retracted position stored in the controller 50 and the actual retracted position output from the position detector 46 match, so that the controller 50 outputs a command signal. And switch 4
8 opens the power circuit to cut off the electric power to the electric motor 40. As a result, the injection device 14 stops at the predetermined retracted position. In the process of molding as described above, by any chance,
When the resin leaks from the injection nozzle 16, the set nozzle touch force set in the controller 50 is corrected to a slightly larger value than before. The calculator 54 performs the calculation again based on the corrected set nozzle touch force to obtain the corrected set stroke and sends it to the memory 56. The storage unit 56 updates the stored data and outputs the updated data to the comparator 58. In this way, it is possible to always apply a small nozzle touch force to the injection nozzle 16 such that resin leakage does not occur.

In the description of the above embodiment, the electric motor 40 is not excited during the injection operation of the injection device 14,
Although the electromagnetic brake 42 is activated, the electromagnetic brake 42 can be activated while the electric motor 40 is in the excited state during the injection operation. Further, although the power transmission mechanism 44 is of the type having the gears 34 and 36 in the above description of the embodiment, it may be of the type having a pulley and a belt or a sprocket and a chain. Further, in the description of the above embodiment, the power transmission mechanism 44 rotates the ball nut 32 and moves in the axial direction without rotating the ball screw 30, but the ball screw 30 is rotated to rotate the ball screw 30. It is also possible to move the nut 32 in the axial direction without rotating it.

[0010]

As described above, according to the present invention, the nozzle touch force can be arbitrarily set within the range of the compression force of the spring, and the resin is not leaked from the injection nozzle. The nozzle touch force can be applied. Therefore, the injection nozzle and the mold are not damaged when the nozzle is touched. Further, the guide pins and the guide bushes are not worn or damaged when the mold is opened and closed. Also,
Since it is easy to change the setting of the nozzle touch force, it is possible to easily perform work such as setup change when changing molding conditions and the like.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a relationship between a spring deflection amount and a nozzle touch force.

[Explanation of symbols]

 12 slide plate 14 injection device 16 injection nozzle 18 mold 20 spring chamber 24 spring 26 spring receiver 28 shaft 30 ball screw 32 ball nut 34, 36 gear 40 electric motor 44 power transmission mechanism 46 position detector 48 switch 50 controller 52 setting Calculator 54 Calculator 56 Memory 58 Comparator

Claims (3)

[Claims] 1. When moving an injection device having an injection nozzle in a direction approaching a mold, a motor drives the injection device via a power transmission mechanism and a spring, while the injection device is moved away from the mold. In order to move the injection nozzle, the injection device moving device of the electric injection molding machine configured to drive the injection device by the electric motor through the power transmission mechanism and without the spring is used. The actual nozzle touch force pressed against the mold is
An injection device movement control method for an electric injection molding machine, characterized in that a deflection amount of a spring is adjusted by controlling an electric motor so as to be equal to a preset nozzle touch force set in advance. 2. An electric motor (40), a power transmission mechanism (44) connected thereto, and an injection device (14) having a power transmission mechanism (44) and an injection nozzle (16). A spring (24), and an electric motor (4
0) the injection device (14) according to the rotating direction of the mold (1
It is possible to move the injection device (14) in a direction toward and away from the mold (8).
When the injection device (14) is driven by the electric motor (40) via the power transmission mechanism (44) and the spring (24), the injection device (1)
When moving 4) in the direction away from the mold (18), the injection device (14) is driven by the electric motor (40) via the power transmission mechanism (44) and not via the spring (24). In the injection device movement control device of the electric injection molding machine configured as described above, the position detector (46) capable of detecting the deflection amount of the spring (24), the injection nozzle (16), and the mold ( Setting device (52) for setting the nozzle touch force to be pressed against 18), and the spring (24) corresponding to the set nozzle touch force
An arithmetic unit (54) for calculating the set deflection amount of, a storage unit (56) for storing the calculated set deflection amount, a calculated deflection amount output from the storage unit (56), and a position detector (46) A comparator (58) for comparing the actual deflection amount output from the electric motor (4) based on the output from the comparator (58).
And a controller (50) for controlling 0), and an injection device movement control device for an electric injection molding machine, comprising: 3. The injection device movement control device for the electric injection molding machine according to claim 2, wherein the timing of generating the nozzle touch force is set in the controller (50).