JPH06106593A - Method and apparatus for displaying pressure waveform of motor-driven injection molding machine - Google Patents

Abstract

PURPOSE:To obtain a pressure waveform having extreme correlation to an actual resin pressure and to effectively utilize it for an operator by displaying an output of a load current from a first driver amplifier of an injection motor as a waveform monitor through a filter having a suitable size. CONSTITUTION:A method for displaying a pressure waveform of a motor-driven injection molding machine 3 comprises the steps of controlling an injection motor 1 according to a command from a first driver amplifier 17 of the motor 1 based on a set value previously set by a controller 16 in an injection dwelling step, and outputting a load current at that time by a torque monitor in the amplifier 17. A filter 21 having a suitable size is installed before an output 23 of the current is input to the controller 16 side thereby to cut OFF high frequency components of the current, thereby providing a smooth waveform. Thus, the waveform having extreme correlation to the resin pressure can be obtained.

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 displaying the pressure of injection, pressure holding and back pressure steps of an electric injection molding machine on a screen as a waveform monitor.

[0002]

2. Description of the Related Art There are various methods and devices for displaying the pressure of the injection, pressure holding, and back pressure processes of a conventional electric injection molding machine as a waveform monitor on the screen. The output of the injection motor was taken directly into the control device and displayed on the screen display as a waveform monitor that had a correlation with the resin pressure.

[0003]

However, such a conventional pressure waveform display method and apparatus for an electric injection molding machine has the following problems. That is, since the output of the injection motor is directly fetched, as shown in FIG. 3A, all the torque required during acceleration / deceleration of the injection motor is also detected, so that there is a correlation with the actual movement of the resin pressure. It was displayed with the addition of a non-existent waveform.

[0004]

According to the present invention, the rotation of the injection motor 1 is converted into a linear motion via a ball screw mechanism 11, and the screw 5 in the heating cylinder 2 is advanced to perform the injection process and the pressure maintaining process. In the pressure waveform display method of the electric injection molding machine, the plasticizing motor 12 interlocked with the screw 5 is rotated to perform the plasticizing step of storing the resin in the heating cylinder 2. First of motor 1
The load current output 23 from the driver amplifier 17 is displayed as a waveform monitor through a filter 21 having an appropriate size, and further suitable for the load current output 23 from the first driver amplifier 17 of the injection motor 1. The above-mentioned problem is solved by fetching it in the control device 16 through the filter 21 having a size and displaying it on the screen display and setting unit 20 as a waveform monitor.

[0005]

In the method and apparatus for displaying the pressure waveform of the electric injection molding machine according to the present invention, the load current output from the torque monitor in the first driver amplifier of the injection motor is once displayed as a waveform monitor through the filter. ,
A waveform similar to the actual resin pressure waveform can be displayed.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a pressure waveform display method and device 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 in the conventional case will be described with the same reference numerals. FIG. 1 is a block diagram with a cross section showing a pressure waveform display method and device of an electric injection molding machine according to the present invention. As is clear from this figure, what is indicated by reference numeral 2 in FIG. 1 is a heating cylinder of the electric injection molding machine 3. This heating cylinder 2 has a nozzle 2a at its tip and is formed in the axial direction thereof. In the formed guide hole 2b,
A screw 5 having a connecting rod 4 is arranged so as to be rotatable and axially movable.

The connecting rod 4 is connected to a cylindrical drive shaft 4A having a U-shaped cross section, and the drive shaft 4A is connected to a ball nut 7 via a thrust bearing 6.
A gear 8 is integrally fitted and provided at an outer peripheral position at the end of the drive shaft 4A.
A ball screw 9 is screwed inside the ball screw 9, and an output shaft 10 of the injection motor 1 is connected to one end of the ball screw 9. The ball nut 7 and the ball screw 9
Constitutes a ball screw mechanism 11, and by rotating the output shaft 10 of the injection motor 1, the drive shaft 4A and the screw 5 can be moved in the axial direction via the ball nut 7.

The rotating shaft 13 of the plasticizing motor 12 provided in parallel with the injection motor 1 is engaged with the ball spline 14 and has a pair of flanges 15a attached to the outer periphery of the ball spline 14. The gear 8 is engaged with the flanged gear 15, and the drive shaft 4A can be rotated by the rotation of the rotary shaft 13. Injection motor encoder 1 provided in the injection motor 1
The detection signal of A is input to the control device 16 and
The detection signal of the plasticizing motor encoder 12A provided in the plasticizing motor 12 is input to the control device 16. Further, a torque monitor (not shown) that outputs a load current of the injection motor 1 is built in the first driver amplifier 17. The filter 21 is provided before inputting the output 23 of the load current to the control device 16. The filter 21 may be provided between the control device 16 and the screen display / setting unit 20.

The method and apparatus for displaying the pressure waveform of the electric injection molding machine according to the present invention is configured as described above, and its operation will be described below. First, in the injection pressure maintaining process, the injection motor 1 is controlled by a command from the first driver amplifier 17 of the injection motor 1 based on the preset value set by the control device 16, and the load current at that time is the first load current. It is output from the torque monitor in the driver amplifier 17. The output 23 of the load current is the control device 16
Since the filter 21 is installed before inputting to the side, if there is no filter, a rising torque is required when the injection speed changes, so a whisker-like waveform is obtained as shown in A of FIG. By inserting 21, the high frequency component of the load current can be cut and a smooth waveform is obtained, as shown in FIG. 2B. As a result, a waveform having a strong correlation with the resin pressure can be obtained.

The cut frequency of this filter 21 is 5 to 5.
Around 20 Hz has been confirmed to be suitable by experiments. By outputting the obtained waveform to the screen display unit, the operator can estimate the resin pressure having a very correlation.

[0011]

Since the method and apparatus for displaying the pressure waveform of the electric injection molding machine according to the present invention are configured as described above, the following effects can be obtained. That is, by installing a filter on the output of the load current, the pressure waveform becomes smooth, and a pressure waveform that is highly correlated with the actual resin pressure can be obtained and can be effectively utilized by the operator.

[Brief description of drawings]

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

FIG. 2 Waveform monitor by the method of the present invention

[Fig. 3] Waveform monitor by the conventional method

[Explanation of symbols]

 1 ... Injection motor 1A ... Injection motor encoder 2 ... Heating cylinder 2a ... Nozzle 2b ... Guide hole 3 ... Electric injection molding machine 4 ... Rod 4A ・ ・ ・ Drive shaft 5 ・ ・ ・ Screw 6 ・ ・ ・ ・ Thrust bearing 7 ・ ・ ・ ・ Ball nut 8 ・ ・ ・ ・ Gear 9 ・ ・ ・ ・ ・ ・ Ball screw 10 ・ ・ ・ Output shaft 11 ・ ・ ・ Ball screw Mechanism 12 ... Plasticizing motor 12A ... Plasticizing motor encoder 13 ... Rotating shaft 14 ... Ball spline 15 ... Collared gear 15a ... Tsuba 16 ... Control device 17 ... -First driver amplifier 18 ... Second driver amplifier 20 ... Screen display and setting section 21 ... Filter 22 ... Input 23 ... Output

Claims (2)

[Claims] 1. A rotation of an injection motor (1) is converted into a linear motion via a ball screw mechanism (11), and a screw (5) in a heating cylinder (2) is advanced to perform an injection process and a pressure-holding process. Then, by rotating the plasticizing motor (12) interlocking with the screw (5), the plasticizing step of storing the resin in the heating cylinder (2) is performed. Method, first driver amplifier (17) of the injection motor (1)
A method for displaying a pressure waveform of an electric injection molding machine, characterized in that the output (23) of the load current is displayed as a waveform monitor through a filter (21) having an appropriate size. 2. A rotation of an injection motor (1) is converted into a linear motion via a ball screw mechanism (11), and a screw (5) in a heating cylinder (2) is advanced to perform an injection process and a pressure-holding process. Then, by rotating the plasticizing motor (12) interlocking with the screw (5), the plasticizing step of storing the resin in the heating cylinder (2) is performed. In the device, a first driver amplifier (17) of the injection motor (1)
The load current output (23) is taken into the control device (16) through a filter (21) having an appropriate size,
A pressure waveform device for an electric injection molding machine, characterized by being displayed as a waveform monitor on a screen display and a setting unit (20).