JPH06856A - Method and device for detecting resin pressure in motor-operated injection molding machine - Google Patents

Abstract

PURPOSE:To indirectly detect a resin pressure by detecting a loard current passing through an ejection motor during an injection and dwell process. CONSTITUTION:A resin pressure detection method and device in a motor- operated injection molding machine is so constructed as to indirectly detect a resin pressure by detecting a load current (25a) passing when an ejection motor (18) is driven at a required hold torque against a resin pressure during an injection and dwell process.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for detecting resin pressure in an electric injection molding machine, and more particularly, to indirectly detect resin pressure by detecting a load current flowing through a protruding electric motor during injection / holding. For new improvements to do.

[0002]

2. Description of the Related Art As a conventional resin pressure detection method for an electric injection molding machine of this type, the configuration shown in FIG. 2 is generally used. That is, reference numeral 1 in FIG.
The one shown by is the fixed mold 2 and the spacer block 3.
It is a mold including a movable side mold 3 including a and a core 3b, and a projecting pin 4 provided in the movable side mold 3 so as to be able to move in and out is provided so as to be able to move in and out of a cavity 5 of the mold 1. .

A resin pressure sensor 6 is provided on the projecting pin 4 in the movable mold 3 so that the resin pressure sensor 6 can detect the resin pressure in the cavity 5 during injection and pressure holding. It is configured.

[0004]

Since the conventional resin pressure detecting method for the electric injection molding machine is configured as described above,
The following issues existed. That is, the resin pressure sensor needs to be installed in the mold by performing a special process, which is restricted by the structure of the mold, and the cost is a problem because the resin sensor is expensive.

The present invention has been made in order to solve the above problems, and in particular, the resin pressure is indirectly detected by detecting the load current flowing through the ejection motor during injection / holding. It is an object of the present invention to provide a resin pressure detecting method and device for an electric injection molding machine.

[0006]

SUMMARY OF THE INVENTION A resin pressure detecting method for an electric injection molding machine according to the present invention detects a resin pressure in a cavity of a mold having a projecting pin that is inserted and removed by a projecting rod that is inserted and extracted through a projecting electric motor. In the resin pressure detection method for the electric injection molding machine, the protrusion motor is driven with a necessary holding torque against the resin pressure applied to the protrusion pin at the time of injection pressure holding, and the protrusion when the holding torque is generated. This is a method of indirectly detecting the resin pressure by detecting the load current flowing in the electric motor.

Further, the resin pressure detecting device for the electric injection molding machine according to the present invention is adapted to detect the resin pressure in the cavity of the mold having the projecting pin which is inserted and extracted by the projecting rod which is inserted and extracted through the projecting electric motor. In the resin pressure detection device of the electric injection molding machine, for comparing the ejection rod position signal from the rotation position detector of the ejection motor and the initial ejection position signal from the ejection driver amplifier that drives the ejection motor. A comparator, a current detector connected to the projecting driver amplifier for detecting a load current flowing in the projecting electric motor, and a resin pressure indicator connected to the current detector. By detecting the resin pressure, the resin pressure is indirectly detected.

[0008]

In the method and apparatus for detecting resin pressure of the electric injection molding machine according to the present invention, after the initial protruding position of the protruding rod is set, the position change of the protruding rod due to the pressure fluctuation applied to the protruding pin during injection / holding is performed. It is detected by the rotational position detector of the protruding motor. The projecting rod position signal from the rotational position detector and the initial projecting position signal of the initial projecting position are compared by a comparator, and when a difference occurs, the projecting rod is controlled to the initial projecting position and at the same time The load current flowing in the motor is detected by the current detector. By converting the detected value of the load current into a pressure value with a converter and displaying it on a resin pressure display, the resin pressure in the mold can be indirectly detected without using a conventional resin sensor.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a resin pressure detecting method and apparatus for an electric injection molding machine according to the present invention will be described in detail below with reference to the drawings. It should be noted that the same or equivalent parts as those of the conventional example are designated by the same reference numerals for description. FIG. 1 is a configuration diagram with a cross section showing a resin pressure detecting device of an electric injection molding machine according to the present invention.

In FIG. 1, reference numeral 1 denotes a fixed mold 2 and a movable mold 3 including a spacer block 3a and a core 3b.
The protruding pin 4 which is provided in and out of the mold is provided in and out of the cavity 5 of the mold 1.

An injection unit 10 is attached to the fixed mold 2.
Nozzle 10a is joined, and the molten resin injected from this nozzle 10a is injected into the cavity 5. The projecting plate 11 joined to the projecting pin 4 provided on the movable mold 3 is configured to be pushed in and out by a projecting rod 13 provided penetrating the movable plate 12 holding the movable mold 3. is there.

A ball screw 1 is attached to the outer end of the protruding rod 13.
4 is formed, and a ball nut 16 having a driven pulley 15 integrally formed on the outer circumference of the ball screw 14 is formed.
Are screwed together.

A protruding electric motor 18 having a rotational position detector 17 at a position slightly separated from the ball screw 14.
Is provided, and the rotating shaft 1 of the protruding electric motor 18
9 is a drive pulley 20 provided with a timing belt 21.
It is connected to the driven pulley 15 via. In addition,
The ball nut 16 and the protruding electric motor 18 described above are fixedly provided to a main body (not shown).

A projecting rod position signal 17a obtained from the rotational position detector 17 for detecting the projecting rod position of the projecting rod 13 is inputted to the comparator 21 and used for driving the projecting electric motor 18. An initial projecting position signal 23 for setting the initial projecting position from the driver amplifier 22 is input to the comparator 21.

The comparison output 21a, which is the difference obtained from the comparator 21, is input to the controller 24, and the control signal 24a from the controller 24 is input to the projecting driver amplifier 22.

The projecting driver amplifier 22 includes:
A current detector 25 for detecting a load current flowing in the protruding electric motor 18 is provided, and a detected value of the load current 25a detected by the current detector 25 is converted into a pressure value 26a by a converter 26. Then, the resin pressure indicator 27 is displayed.

Next, a case where the resin pressure is actually detected in the above-mentioned structure will be described. First, before injection starts
By inputting the initial projecting position signal 23 from the projecting driver amplifier 22 to the projecting electric motor 18, the projecting pin 4 is influenced via the ball nut 16, the ball screw 14, the projecting rod 13 and the projecting plate 11 to the molded product. The molten resin is injected into the cavity 5 from the injection unit 10 in a state where the molten resin is projected to the initial projecting position.

After the above-mentioned injection, during the injection / pressure holding, the protruding pin 4 is caused by the pressure fluctuation in the cavity 5 of the mold 1.
As the pressure applied to the
The position change is detected by the rotational position detector 17 of the protruding electric motor 18 that rotates due to the position change.

In the above-mentioned state, the ejecting rod position signal 17a detected in accordance with the position change and the initial protruding position signal 23 are compared by the comparator 21, and if there is a difference, the comparison output 21a is sent to the controller 24. From this controller 24, a control signal 24a is input from the controller 24 to the projecting electric motor 18 so as to correct the position with a necessary control torque to the projecting driver amplifier 22.

The load current 25a of the ejecting electric motor 18 which generates the holding torque required for correction with the above-mentioned control torque is detected by the current detector 25, and this load current 25a is converted into a pressure value by the converter 26. At the same time, the resin pressure 26a obtained by the converter 26 is displayed on the resin pressure display 27. Therefore, the resin pressure in the mold 1 can be indirectly detected.

[0021]

The method and apparatus for detecting resin pressure of the electric injection molding machine according to the present invention are configured as described above,
The following effects can be obtained. That is,
Since the resin pressure is indirectly detected by detecting the load current flowing through the protruding motor during pressure holding, there is no need to use a resin sensor as in the past, and the resin pressure in the mold is sufficiently accurate with a simple configuration. It is possible to measure with.

[Brief description of drawings]

FIG. 1 is a block diagram with a cross section showing a resin pressure detecting device of an electric injection molding machine according to the present invention.

FIG. 2 is a cross-sectional view of essential parts showing a resin pressure detection device of a conventional electric injection molding machine.

[Explanation of symbols]

 1 Mold 4 Protruding pin 5 Cavity 17 Rotation position detector 17a Protruding rod position signal 18 Motor for ejecting 21 Comparator 22 Driver amplifier for ejecting 23 Initial ejecting position signal 25 Current detector 25a Load current 27 Resin pressure indicator

Claims (2)

[Claims] 1. A mold having a protruding pin (4) which is inserted / removed by a protruding rod (13) which is inserted / removed via a protruding electric motor (18).
In the resin pressure detection method for an electric injection molding machine, which detects the resin pressure in the cavity (5) of (1), the protrusion motor against the resin pressure applied to the protrusion pin (4) during injection pressure holding. (18) is driven with a required holding torque, and the load current (25
A resin pressure detecting method for an electric injection molding machine, which indirectly detects the resin pressure by detecting a). 2. A mold having a protruding pin (4) which is inserted / removed by a protruding rod (13) which is inserted / removed via a protruding electric motor (18).
In the resin pressure detection device of the electric injection molding machine configured to detect the resin pressure in the cavity (5) of (1), the protruding rod position signal from the rotational position detector (17) of the protruding electric motor (18). (17a) and a comparator (21) for comparing the initial projecting position signal (23) from the projecting driver amplifier (22) that drives the projecting electric motor (18), and the projecting driver amplifier (22) ), A current detector (25) for detecting a load current (25a) flowing in the protruding electric motor (18),
An electric motor comprising a resin pressure indicator (27) connected to the current detector (25) and indirectly detecting the resin pressure by detecting the load current (25a). Resin pressure detector for injection molding machine.