JPH0353910A - Indicating method for die pressing state - Google Patents

Abstract

PURPOSE:To enable the die pressing state to be grasped readily by detecting the load of each tie-bar in use of an ultrasonic measuring unit, and transmitting the detected value to an NC control unit for making it perform an indicating process, and further indicating, on an indicating screen of the NC control unit, the loads regarding each tie-bar as a pressing balance, or the total of these loads as a pressing force. CONSTITUTION:When CPU 20 is inputted with a pressing state indicating command from an operating board 23, an NC control unit 19 is made into a die pressing state indicating mode in accordance with control programs in a ROM 21, and the detected value coming in an input and output circuit 24 from an ultrasonic measuring unit 16 is taken therein so as to be indicated on CRT 25 by indicating process. In this instance, the indicating patterns are set in each indication of a die pressing balance and die pressing force, and the indication of the die pressing balance is that the loads in each tie-bar 5 are converted into numerals or graphs, and the indication of the die pressing force is respectively indicated such that the loads of each tie-bar 5 are totaled prior to the indicating process, and the values thereof are processed and converted into graphic graphs and the like which can readily judge the difference between the numerals or the set die pressing force.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for displaying the clamping state of a mold clamping device such as an injection molding machine.

Conventional technology In the three-platen mold clamping device used in injection molding machines, the fixed platen fixed to the machine base and the rear platen, which can be moved slightly back and forth relative to the machine base, are usually connected by four tie bars. A movable platen is attached to the tie bar so that it can move back and forth.

One end of each tie bar is fixed to a fixed platen, and the other end passes through the rear platen and a feed screw is formed in that part.
A mold thickness adjustment nut with an integral sprocket is screwed together.

A movable mold is attached to the movable platen, and a fixed mold is attached to the fixed platen. The distance between the movable platen and the fixed platen according to the thickness of the mold is adjusted by rotating the mold thickness adjusting nut with the mold thickness adjusting motor.

The movable platen is connected to the rear platen by a mold clamping mechanism (for example, a toggle link mechanism driven by a servo motor) constructed between them, and the movable mold is pressed against the fixed mold by the mold clamping mechanism.

The mold clamping state is maintained by elastically deforming the tie bars and elongating them via the rear platen due to the reaction force when the mold clamping mechanism presses the movable mold against the fixed mold.

In the mold clamping state, the mold clamping force set at an appropriate level is exerted, and the force acts on the mold evenly or in a predetermined distribution, which prevents cracks or shorts in the molded product. This is important to ensure that this does not occur. For this purpose, it is preferable to accurately grasp and adjust the mold clamping state at the time of shipment, installation, or periodic inspection of the injection molding machine.

Conventionally, in the mold clamping device of injection molding equipment, load cells and sensors have been used to detect the magnitude of mold clamping force in order to obtain data necessary for NC control. There is nothing to display the current value of force or the balance of clamping force. Additionally, the load cell sensor has the disadvantage that it requires a special mounting structure to avoid receiving preload from other structural parts.

Furthermore, when the mold clamping device is completed or periodically inspected, the elongation of the tie bars is measured using a dial gauge to determine whether the specified mold clamping force is being exerted. It is troublesome to contact the end face of the tie bar vertically, and in addition, it is necessary to keep the dial gauge fixed so that the 7F position does not fluctuate during measurement.

Furthermore, in this type of device that attempts to detect the elongation of the tie bar by the deformation of one end of the tie bar, if there is deformation such as the tie bar curving during mold clamping or each platen warping, it is difficult to accurately measure the elongation. Unable to detect.

Problems to be Solved by the Invention An object of the present invention is to provide a method for displaying the clamping state of a mold clamping device equipped with an NC control device so that the clamping state (clamping force and balance thereof) can be easily grasped. do.

Means to solve problems The load on each tie bar is detected using an ultrasonic length measuring device.

The detected value is transmitted to the NC control device to perform display processing.

The load related to each tie bar is displayed as the mold clamping balance, and the total of these loads is displayed as the mold clamping force on the display screen of the NC control device.

4. Detection of the load by the action ultrasonic length measuring device facilitates the detection of the substantial load on each tie bar and also provides more detailed detection values.

Displaying the mold clamping balance and mold clamping force on the display screen of the NC control device provides the mold clamping state in a form that is easy for the operator to grasp.

Embodiment Figure 1 shows a 3-butene mold clamping device 1 in an injection molding machine.
As in the conventional example, the fixed platen 2,
The fixed platen 2 and the rear platen 4 have a movable platen 3 and a rear platen 4, and the fixed platen 2 and the rear platen 4 have four typers 5 evenly arranged with respect to the mold clamping axis a (corresponding to the line of action of the mold clamping force).
The movable platen 3 is fitted into these tiepers 5 and is movable back and forth.

The fixed platen 2 is fixed to the machine base 6, and the rear platen 4 is placed on the machine base 6 and can be moved back and forth over a certain distance.

The distance between the fixed platen 2 and the rear platen 4 is determined by the tie bar nut 7 screwed onto the front end of each tieper 5 and in contact with the front surface of the fixed platen, and the feed screw 8 formed at the rear of the tie bar 5. The mold thickness adjustment nut 9 with a sprocket is in contact with the rear surface of the mold thickness adjustment nut 9.

The movable platen 3 has a toggle link mechanism 10 which is simply illustrated.
The toggle link mechanism 10 is connected to the rear platen 4 at
is driven by a mold clamping motor 11 (servo motor). In addition, the mold clamping nuts 9 on each tie bar 5 are synchronized by a single chain 12 hooked around the sprocket and driven by a mold thickness adjustment motor 13 (servo motor) fixed to the rear platen 4. rotated in unison.

A movable mold 1 - 4 is mounted on the front surface of the movable platen 3 , and a fixed mold 15 is mounted on the rear surface of the fixed platen 2 .

A probe of an ultrasonic length measuring device 16, that is, an ultrasonic transmitting/receiving element 17 is firmly adhered to the front end surface of each tie bar 5.

The ultrasonic length measuring device 16 emits ultrasonic waves (
The length of the tie bar 5 is measured by transmitting a signal (approximately 10MH2) and receiving the echo from the rear surface, and the elongation of the tie bar is calculated by comparing it with the unloaded length of the same tie bar 5, which has been measured and memorized in advance. And then typer 5
From the correlation between external force and relationship established by the material of
The current load on the tie bar 5 is calculated and output.

Note that the principle of such an ultrasonic length measuring device is well known.

The mold clamping motor 11 and the mold thickness adjustment motor 13 are connected to an NC control device 19 via a servo drive circuit 18, and are driven by the commands thereof. Further, the output of the ultrasonic length measuring device 16 is connected to the human output circuit 24 of the NC control device 19.

FIG. 2 is a block diagram of the NC control device 19 in the embodiment, and 20 is a microprocessor (hereinafter referred to as CPU);
21 is a ROM that stores control programs, 22 is a RAM that is used for storing machining conditions and various settings, and temporary storage of data, etc., 23 is an operation panel for inputting various commands and setting values, etc., and 24 is an input/output panel. an output circuit, 25 a CRT as a display screen, and 26 the servo drive mechanism 18;
It is a servo interface that connects to.

The output line of the ultrasonic length measuring device 16 is connected to the human/output circuit 24 .

The mold clamping device 1 is also equipped with other members and mechanisms that are included in a normal mold clamping device, such as an ejector device (not shown), and the control device 19 is also used to make the injection molding machine operate normally. It is equipped with many necessary circuits and means.

Under the injection molding mode control of the NC control device 19, the mold clamping motor 11 is driven via the servo interface 26 and the servo drive circuit 18, and mold clamping and mold opening operations are performed. If the distance between the fixed platen 2 and the movable platen 3 is inappropriate due to the relationship between the mold clamping stroke and the mold thickness, N
The C control device 19 is set to the mold thickness adjustment mode, and the mold thickness adjustment motor 13 is driven in the same manner as described above, and the interval is adjusted to the value set from the operation panel 23.

The mold clamping state is displayed as follows.

The ultrasonic length measuring device 16 measures the length of each tie bar 5 when the mold clamping device 1 is in an unloaded state, that is, in a mold open state, and this is stored in the ultrasonic length measuring device 16. The ultrasonic length measuring device 16 also stores in advance the correlation (converted value, etc.) between the elongation of the tieper 5 and the load.

Next, the mold clamping device 1 is brought into the mold clamping state, and the length of each tie bar 5 is measured again. Thereby, the ultrasonic length measuring device 16 obtains the elongation of each tie bar 5, calculates the load on each tie bar 5 from the stored correlation between the elongation and the load, and transmits this to the input/output circuit 24 as a detected value.

When the CPU 20 receives a manual mold clamping status display command from the operation panel 23, the CPU 20 displays N according to the control program in the ROM 21.
The C control device 19 is set to the mold clamping state display mode, and the detected value (
Load of each tie bar 5) is taken in, and by display processing, C
Display on RT25.

In this case, the display process itself is the same as that provided by the conventional NC control device, but the display pattern is set to display the mold clamping balance and mold clamping force, and the display of the mold clamping balance is based on the load at each tie bar 5. is processed into a form that makes it easy to visually compare each tie bar phase B, such as numbers and graphs.
In addition, the mold clamping force is displayed by summing up the loads on each tie bar 5 before display processing, and processing the resulting value into a number or an isomorphic graph that allows you to easily determine the difference from the set mold clamping force. It is processed and displayed as such.

If the NC control device 16 is set to the display mode early and the mold clamping state is displayed over time in combination with the time or position signal from the mold clamping motor 11, the mold clamping force and mold clamping balance until the mold clamping is completed can be adjusted. Changes can be observed dynamically.

The display is erased by changing the control mode of the control device 19.

The above is an example, and the ultrasonic length measuring device 16 may simply detect the length of each tie bar 5, and the subsequent elongation and the corresponding load may be calculated on the CPU side. .

The probe 17 of the ultrasonic length measuring device 16 may be bonded to the rear end surface of the tie bar.

Effects of the invention The mold clamping condition (mold clamping force, mold clamping balance) can be grasped at a glance.

Even in a mold clamping state where the tie bars and each platen are deformed (curved or warped), the elongation of each tie bar is substantially detected, making it possible to accurately display the mold clamping state.

By dynamically understanding the mold clamping state, it is possible to know the characteristics of the mold, and this data can be used for mold management and NC control.

The parallelism between the movable platen and the fixed platen or rear platen can be monitored by the mold clamping balance.

Since the probe of the ultrasonic length measuring device can be left attached, it is possible to easily check the mold clamping state at any time.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram schematically showing an apparatus for implementing the present invention, and FIG. 2 is a diagram schematically showing an NC control device. DESCRIPTION OF SYMBOLS 1... Mold clamping device, 5... Tie bar, 9... Mold thickness adjustment nut, 16... Ultrasonic length measuring device, 17... Probe, 19... NC control device. Procedures Amendment Book September 1989 II11

Claims (1)

[Claims] In a mold clamping device equipped with an NC control device, the load on each tie bar in the mold clamping state is detected by an ultrasonic length measuring device with an ultrasonic transmitting/receiving element bonded to one end surface of each tie bar, and the detected value is A mold clamping state display method characterized by displaying the load related to each tie bar as a mold clamping balance via an NC control device, and displaying the sum of these loads as a mold clamping force on a display screen of the NC control device.