JPH0626840B2 - Method and apparatus for detecting resin pressure in mold of electric injection molding machine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for detecting a resin pressure in a mold of an electric injection molding machine and an apparatus therefor, and particularly to a mold clamping method without providing a sensor in the mold. The present invention relates to a new improvement for indirectly detecting the resin pressure in a mold by the rotation detection signal of the electric motor.

[Conventional technology]

There are various methods for detecting the resin pressure in a mold in an electric injection molding machine of this type that has been conventionally used. Among them, a typical configuration will be described. The configuration shown in FIG. 2 and FIG. Can be mentioned.

That is, in FIG. 2, what is indicated by reference numeral 1 is a fixed mold, and a movable mold 2 is movably opposed to the fixed mold 1.

A cavity 3 communicating with a gate 1a formed in the fixed mold 1 is formed between the molds 1 and 2, and a resin pressure sensor 1c embedded in the fixed mold 1 is provided.
One end 1b of the is connected to the cavity 3.

Therefore, the pressure inside the mold generated by the resin injected and filled into the molds 1 and 3 after the mold is clamped is measured by the resin pressure sensor 1c.

Further, in FIG. 3, reference numeral 1 denotes a fixed mold, and a movable mold 2 is movably opposed to the fixed mold 1.

A cavity 3 communicating with the gate 1a formed in the fixed mold 1 is formed between the molds 1 and 2, and an ejector provided in the movable mold 2 in communication with the cavity 3 is formed. A pressure sensor 2b is provided at the rear end of the rod 2a.

Therefore, by the pressure sensor 2b, the cavity 3
The resin pressure inside was measured indirectly.

Furthermore, the pressure-holding switching from the injection step to the pressure-holding step, the pressure-holding control, the multistage mold clamping control, and the like are performed based on the detection signals obtained by the resin pressure sensor 1c and the pressure sensor 2b.

[Problems to be Solved by the Invention]

Since the conventional method of detecting the resin pressure in the mold of the electric injection molding machine is configured as described above, it has the following problems.

That is, in order to install the resin pressure sensor in the fixed mold as shown in FIG. 2 or to provide the pressure sensor after the ejector rod in the movable mold as shown in FIG. 3, the fixed mold and the movable mold are arranged. Was extremely expensive and required special processing to be built in.

Also, the resin pressure generated in the cavity depends on the distance from the gate, the wall thickness, etc., and the position where the sensor is installed in the cavity is an important factor. Even if such pressure is used for controlling the injection pressure-holding process, it may not be effective for an actual molded product, and there has been a serious problem that it is extremely difficult to obtain high accuracy.

The present invention has been made to solve the above problems, in particular, without providing a sensor in the mold, the resin pressure in the mold is detected by the rotation detection signal of the mold clamping motor after the start of injection. An object of the present invention is to provide a method and apparatus for detecting resin pressure in a mold of an electric injection molding machine which is adapted to perform detection.

[Means for Solving the Problems]

A method for detecting a resin pressure in a mold of an electric injection molding machine according to the present invention is a mold of an electric injection molding machine in which a mold clamping motor is used to clamp the mold to detect the resin pressure in the mold. In the internal resin pressure detection method, a first step of closing the mold in a mold open state and performing initial mold clamping with a preset torque, and a step of filling the mold with resin after the completion of the first step. It is a method comprising two steps and a third step of detecting that the mold clamping motor has rotated in the second step, and indirectly detecting the resin pressure in the mold by the state of the rotation. .

Another aspect of the invention is an in-mold resin pressure detecting device for an electric injection molding machine, which is an electric injection molding machine configured to detect a resin pressure in a mold by performing mold clamping with a mold clamping motor. In the in-mold resin pressure detection device, a rotation detection unit that detects the rotation of the mold clamping electric motor, and a rotation position setting unit that presets a rotational position set value in the rotation of the mold clamping electric motor,
Connected to the rotation detecting means and the position setting means, and outputs a comparison output signal when a deviation occurs between the predetermined value set in the position setting means after the start of injection and the rotation detection value detected by the rotation detecting means. And a comparison means for performing the above, and the resin pressure in the mold is indirectly detected by the rotation detection value.

[Work]

In the method and apparatus for detecting resin pressure in a mold of an electric injection molding machine according to the present invention, first, a mold in a mold open state is
The mold clamping motor is driven to perform the initial mold clamping with a preset torque, and after the injection is started, the filling of the resin in the cavity progresses and the resin pressure pushes the movable mold to open the mold. However, at this time, in order to hold the position of the movable mold, the mold clamping motor goes into the servo lock state.
Torque is applied.

In this case, the rotation detector provided in the mold clamping electric motor detects the rotation detection value at which the rotation shaft of the mold clamping electric motor rotates due to the opening of the mold after the start of injection, thereby detecting the resin inside the mold. The pressure can be detected indirectly.

〔Example〕

Hereinafter, preferred embodiments of a method for detecting resin pressure in a mold and an apparatus therefor in an electric injection molding machine according to the present invention will be described in detail with reference to the drawings.

It should be noted that the same or equivalent parts as those of the conventional example will be described using the same reference numerals.

FIG. 1 is an overall configuration diagram for showing an electric injection molding machine according to the present invention.

First, in FIG. 1, a reference numeral 1 denotes a fixed mold fixed to a fixed platen 4 and having a gate portion 1a. The fixed mold 4 is opposed to the fixed platen 4 and is fixed at a predetermined distance. Four tie bars 6 (only two are shown in the drawing) are fixedly provided between the mold clamping housing 5 and the mold clamping housing 5.

A movable plate 7 having a movable mold 2 on each of the divers 6
Is provided so as to be movable in the axial direction, and this fixed mold 1
A cavity 3 for molding a resin is formed between the movable mold 2 and the movable mold 2, and the cavity 3 is the gate 1
It communicates with a.

A nozzle portion 8a of a screw cylinder 8 is disposed in engagement with the fixed plate 4 so as to be joined to the gate portion 1a. Inside the screw cylinder 8, an injection motor 9 is coupled to an injection drive portion. A screw 11 to which 10 is connected is rotatably provided.

A ball screw 12 is provided at a central position of the movable plate 7, and a tip portion 12a of the ball screw 12 is inside a rotary shaft 13 fixedly provided on the mold clamping housing 5 via bearings 5a and 5b. It is screwed with the ball nut 14 of
The movable plate 7 is configured to move in the axial direction by the rotation of the rotary shaft 13.

The end portion 13a of the rotary shaft 13 has the mold clamping housing 5
And a pulley 14 is integrally provided on the end 13a.
It is connected via a timing belt 17 to a flanged pulley 16 provided on a rotary shaft 15a of a mold clamping electric motor 15 attached to an extension portion 5c formed in the mold clamping housing 5 through a timing belt 17.

At the rear of the mold clamping motor 15, a rotation detecting means 1 including an encoder for detecting the rotation of the rotary shaft 15a is provided.
8 is provided, and the rotation detection value 18a of the rotation detector 18 is input to the mold clamping driver amplifier 19 for driving the mold clamping electric motor 15.

The rotation detection value 18a is also input to the comparison unit 21 to which the rotation position setting value 20a from the rotation position setting unit 20 is input, and the rotation position setting value 20a is also input to the mold clamping driver amplifier 19. There is.

The comparison output signal 21a from the comparison means 21 is input to the controller 22 for outputting the control signal 22a to the mold clamping driver amplifier 19, and the output signal 22b of the controller 22 is the injection driver amplifier 23. It is supplied to the injection electric motor 9 after being amplified by.

Further, the rotation detecting means 18 detects the degree of rotation of the rotating shaft 15a of the mold clamping electric motor 15 indicating the moving position of the movable mold 2 when the mold opening occurs during the injection pressure holding, and the comparing means 21. After the injection is started, the rotation detection value 18a is compared with the rotation position setting value 20a preset in the position setting means 20, and the driver amplifier 1 for mold clamping according to the difference is compared.
9, the degree of rotation of the mold clamping motor 15 is the rotation set value 20a.
The mold clamping electric motor 15 is controlled to be in a servo lock state so as to match with, and the comparison unit 21 compares the rotation position set value 20a with the rotation detection value 18a. Comparator 21 to controller 2
A high torque rotation instruction is output to the mold clamping driver amplifier 19 via 2 to operate the mold clamping electric motor 15 with high torque.

The in-mold resin pressure detecting device of the electric injection molding machine according to the present invention is configured as described above, and its operation and method will be described below.

First, the mold clamping motor 15
By driving, the initial mold clamping is performed with a preset torque, and the injection electric motor 9 and the injection driving unit 10 are driven.
The screw 11 is moved forward via to start injection.

After the injection is started, the filling of the resin in the cavity portion 3 progresses and the movable mold 2 is pushed back by the resin pressure, and the movable mold 2 tries to open. At this time, the mold clamping electric motor 15 is moved to the above-mentioned servo. Since the lock state is set, the controller 2 is attached to the mold clamping motor 15 in order to maintain the position of the movable mold 2.
A load current is applied from 2 through the mold clamping driver amplifier 19 to apply torque.

Therefore, the rotation detection means 1 provided in the mold clamping motor 15
After the start of injection, by detecting the rotation speed or rotation position of the rotation shaft 15a of the mold clamping motor 15 rotated as the movable mold 2 moves backward as the rotation detection value 18a, the same as described above. The rotation detection value 18a can indirectly be used as the resin pressure in the mold to perform multistage mold clamping, injection holding pressure switching, holding pressure control, and the like.

〔The invention's effect〕

Since the method and apparatus for detecting the resin pressure in the mold of the electric injection molding machine according to the present invention are configured as described above, the following effects can be obtained.

That is, after the mold is closed by the initial mold clamping force, the rotation detector detects that the mold clamping motor has rotated, so that the resin pressure inside the mold can be indirectly detected. Therefore, it is not necessary to incorporate a special sensor in the mold, the cost of the mold can be reduced, and uncertainties due to local measurement values that can be measured only at the sensor setting location with the conventional resin sensor It is possible to eliminate low-precision control based on data and achieve high-precision injection process control.

[Brief description of drawings]

FIG. 1 shows a method and apparatus for detecting resin pressure in a mold of an electric injection molding machine according to the present invention. FIG. 1 is a block diagram, and FIGS. 2 and 3 are conventional molds. It is sectional drawing which shows a structure. 1 is a fixed mold, 2 is a movable mold, 15 is a mold clamping motor, 1
Reference numeral 8 is rotation detection means, 20 is position setting means, 20A is current setting means, and 21 is comparison means.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsuhiro Fujii 1-6-1, Funakoshi Minami, Aki-ku, Hiroshima City, Hiroshima Prefecture Japan Steel Works, Ltd. (56) Reference Japanese Patent Laid-Open Publication No. 59-3332 (JP, A) Kaihei 1-168420 (JP, A)

Claims (2)

[Claims] 1. A method for detecting a resin pressure in a mold of an electric injection molding machine, wherein a mold (1, 2) is clamped by a mold clamping motor to detect a resin pressure in the mold. Close the open molds (1,2) and perform the initial mold clamping with preset torque, and after the first process is finished, resin is applied to the molds (1,2). It comprises a second step of filling and a third step of detecting that the mold clamping motor (15) has rotated in the second step, and indirectly detects the resin pressure in the mold by the state of rotation. A method for detecting resin pressure in a mold of an electric injection molding machine, characterized in that. 2. An in-mold resin pressure detection device for an electric injection molding machine, wherein a mold (1, 2) is clamped by a mold clamping electric motor (15) to detect a resin pressure in the mold. In, the rotation detection means (18) for detecting the rotation of the mold clamping electric motor (15), and the rotational position setting means (20) for presetting the rotational position setting value in the rotation of the mold clamping electric motor (15), , The rotation detection means (1
8) and the rotation position setting means (20), the rotation position setting value set in the rotation position setting means (20) after the start of injection and the rotation detection value detected by the rotation detecting means (18). An electric motor having a comparison means (21) for outputting a comparison output signal when a deviation occurs, and being configured to indirectly detect the resin pressure in the mold by the rotation detection value. Device for detecting resin pressure in mold of injection molding machine.