JPH0577297A - Displaying method for clamping force in injection molding machine - Google Patents

Abstract

PURPOSE:To facilitate clamping force adjustment and prevent the clamping force from exceeding an allowable value of a machine in an injection molding machine wherein a toggle mechanism is driven by a servomotor to perform mold clamping operation and adjustment of mold thickness and mold clamping force is performed by a mold thickness adjustment motor by a method wherein the amount of mold clamping force is obtained after setting mold thickness to compute mold clamping force and display it. CONSTITUTION:A toggle-movable platen position conversion table that shows theoretical position relationships between a toggle and a movable platen is shown within broken lines, wherein 0-point of movable platen position shows fixing point of a mold and 0-point of the toggle position shows completion position of mold clamping. When mold thickness is adjusted, a toggle position (a) is read by a toggle position detector attached to a servomotor to obtain a converted movable platen position (e) using said table. Next, an actual movable platen position (b) is read by a movable platen position detector mounted to the movable platen. An amount of mold clamping (c) is determined by e-b. By mutiplying (c) by a tie bar expansion coefficient (k), a mold clamping force is obtained, which is displayed and when said force exceeds an allowable value, an alarm is displayed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is directed to moving a movable platen by driving a toggle mechanism with a servo motor to perform mold clamping, and moving a movable platen with a mold thickness adjusting motor to adjust mold thickness and clamping force. The present invention relates to a method for displaying a mold clamping force in an injection molding machine that performs adjustment.

[0002]

2. Description of the Related Art FIG. 2 is a block diagram showing a mold clamping adjustment and a mold thickness adjustment of a vertical injection molding machine. 11 is a toggle drive servo motor,
12 is a toggle position detector, 13 and 15 are pulleys, 1
4 is a synchro belt that connects the pulleys 13 and 15,
Reference numeral 16 is a ball screw, and 17 is a toggle mechanism. One end of the toggle mechanism 17 is rotatably fixed to a fixed platen 18, and the other end is rotatably fixed to a toggle receiving plate 19. The movable platen 110 is connected to the toggle receiving plate 19 via a tie bar 111. Mold thickness adjusting nut 1
Reference numeral 12 is connected to a mold thickness adjusting motor 114 by a chain 113, and as the mold thickness adjusting motor 114 rotates, the mold thickness adjusting nut 112 rotates and the tie bar 111 moves up and down, and the movable platen 110 connected thereto moves up and down. .. The movable platen position detector 115 is fixed to the fixed platen 18,
The rack 116 fixed to the movable platen 110 is rotated by the vertical movement to detect the movable platen position. The up-and-down operation of the movable platen 110 is performed by the rotation of the toggle drive servo motor 11 and the die thickness adjusting motor 114. The movable platen position detector 115 rotates together, and only the movable platen position detector 115 rotates during vertical movement (mold thickness adjustment, mold clamping force adjustment operation) by the mold thickness adjustment motor 114. To adjust the mold clamping force, rotate the mold thickness adjusting motor 114,
This is performed by changing the effective length of the tie bar 111. If the effective length of the tie bar becomes longer, the amount of tie bar elongation during mold clamping decreases and the mold clamping force decreases. Conversely, if the mold thickness adjusting motor 114 is rotated in the direction in which the effective length of the tie bar contracts,
The mold clamping force increases.

FIG. 6 shows a control block diagram for conventional mold clamping adjustment and mold thickness adjustment. Reference numeral 21 denotes a switch group for operating the machine, which is transmitted to the machine control unit 210 via the switch reading unit 24. In the machine control unit 210, a signal from the switch reading unit 24 is passed through the corresponding operation control units (the mold thickness control unit 210a and the toggle control unit 210b), and in the mold thickness adjusting operation, the motor drive unit 211 is used to adjust the mold thickness three-phase induction motor. When the mold is opened and closed, the toggle drive servomotor 11 is actuated by the servo control unit 212 when the mold is opened and closed, and the corresponding mechanical operation is performed. Reference numeral 23 is a teaching unit for setting various data, and a storage unit 2 is provided via a teaching data reading unit 26.
The data set to 9 is stored. The toggle position detector 12 transmits the toggle position to the toggle control unit 210b via the position reading unit 213. Movable platen position detector 11
5 transmits the movable platen position to the toggle control unit 210b via the position reading unit 214. In the mold clamping operation, the toggle position detector 12 is controlled to send the toggle drive servomotor 11 to the position of the preset top dead center of the toggle, and in the mold opening operation, the movable platen position detector 115.
Is controlled to feed the toggle drive servomotor 11 to a position corresponding to the mold opening position.

In the injection molding machine which generates the mold clamping force by the elongation of the tie bar as described above, the conventional method for calculating the mold clamping force is the conventional method of adjusting the mold clamping force by the mold thickness adjusting nut. The operator calculates the mold clamping force by converting the amount of tie bar expansion to the screw pitch, and the mold clamping operation is performed after adjusting the mold clamping force, the tie bar elongation is directly detected by the measuring instrument, and There is a method of calculating the tightening force.

[0005]

However, the above-mentioned two conventional methods have the following problems. That is, in the former method, it is difficult to set the accurate mold clamping force due to the adjustment by the person, and in the latter method, the adjustment of the mold clamping force due to the mold clamping operation is repeatedly performed, so that the adjustment takes time. There was a problem. Further, even if the mold clamping force exceeds the allowable amount of the machine, there is no method for detecting this. The present invention has been made under the circumstances as described above, and an object of the present invention is to adjust the mold clamping force without performing a mold clamping operation and to calculate and display an accurate mold clamping force for an operator to adjust the time. The object of the present invention is to provide a method for displaying the mold clamping force, in which the warning is given when the mold clamping force exceeds the allowable value.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a mold clamping force display method in an injection molding machine, and the above object of the present invention is to move a movable platen by driving a toggle mechanism by a servo motor to mold clamping. The movable platen is moved by a mold thickness adjusting motor to perform mold thickness adjustment and mold clamping force adjustment, and a toggle position detecting means for detecting a toggle position by a detector attached to the servo motor; In an injection molding machine comprising a movable platen position detecting means for detecting a movable platen position by a detector mechanically coupled to the platen, and a mold thickness setting means for setting the relationship between the toggle position and the movable platen position, The difference between the movable platen position after setting the mold thickness and the movable platen position converted from the toggle position is defined as a mold clamping amount, And storage means for storing the amount provided,
This is achieved by calculating and displaying the mold clamping force from the mold clamping amount and displaying a warning when the mold clamping force exceeds an allowable value.

[0007]

According to the present invention, when the die thickness is adjusted, the amount of tie bar extension is determined from the positional relationship between the toggle position obtained by the servo motor detector and the movable platen position obtained by the detector mechanically coupled to the movable platen. Then, the mold clamping force is calculated and displayed based on this elongation amount, and if the mold clamping force exceeds the machine allowable value, an alarm is displayed. Since the mold clamping force is displayed during the adjustment of the mold clamping force, the adjustment becomes easy, and it is possible to prevent the mold clamping force from exceeding the allowable value of the machine due to a warning alarm.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a mechanism diagram of mold clamping adjustment and mold thickness adjustment of a vertical injection molding machine which carries out the method of the present invention. In the conventional control system for mold clamping adjustment and mold thickness adjustment shown in FIG. 6, a conversion unit 41 for converting the movable platen position from the toggle position, and a difference between the actual movable platen position and the converted movable platen position obtained by the conversion unit 41. A calculation unit 42 for calculating the mold clamping force from the above and a comparison unit 43 for comparing the calculated mold clamping force with the machine allowable value and outputting a warning when the allowable value is exceeded are newly added. ..

FIG. 3 shows the relationship between the positions detected by the toggle position detector 12 and the movable platen position detector 115. The plus direction is the mold opening direction and the minus direction is the mold clamping direction. The origin O of the movable platen position detector 115 corresponds to the contact point of the mold. The origin O of the toggle position is the mold clamping completion position. The inside of the broken line is a graph showing a theoretical positional relationship between the toggle position and the movable platen position, which is referred to as a toggle-movable platen position conversion table 44. If the current toggle position is position a and the position indicated by the movable platen position detector 115 at that time is position b, the movable platen position e calculated from the toggle position a by the conversion table 44 and the actual movable platen position b The difference c from the above is obtained as the elongation amount of the tie bar during mold clamping. The mold clamping force can be calculated by multiplying this extension amount by the tie bar expansion / contraction force constant. In adjusting the mold clamping force, the toggle-movable platen position conversion table 44 shifts up and down due to the vertical movement of the movable platen 110 by the mold thickness adjustment motor 114, and the amount of expansion c of the tie bar changes.

FIG. 4 shows a schematic flowchart of the mold clamping force detection process. First, the toggle position is read from the toggle position detector 12 (step S1), and the converted movable platen position is obtained using the toggle-movable platen position conversion table 44 (step S2). Next, the actual movable platen position is read from the movable platen position detector 115 (step S
3) Obtain the difference from the previously converted movable platen position, and multiply the tie bar expansion / contraction force constant k to calculate the mold clamping force (step S).
4). The calculated mold clamping force is displayed (S step S
Along with 5), the maximum mold clamping force of the machine is compared (step S6), and if the maximum allowable value is exceeded, a warning to that effect is displayed (step S7). FIG. 5 shows an example of a screen display of the mold clamping force in the vertical injection molding machine embodying the present invention. 6
Reference numeral 1 is a display of the current position of the movable platen, and 62 is a display of the currently set mold clamping force.

[0011]

By displaying the mold clamping force, the operator can easily and accurately adjust to the desired mold clamping force, and the working time for setup change can be shortened.
Also, in the unlikely event that the mold clamping force exceeds the allowable value of the machine, the operator can know it in advance.

[Brief description of drawings]

FIG. 1 is a block diagram showing a control system for mold clamping adjustment and mold thickness adjustment of a vertical injection molding machine that carries out the method of the present invention. ..

FIG. 2 is a mechanism diagram of mold clamping adjustment and mold thickness adjustment of a vertical injection molding machine that carries out the method of the present invention.

FIG. 3 is a diagram for explaining a relationship between a toggle position and a movable platen position and a mold clamping force generation amount in a toggle operation of an injection molding machine using a toggle mechanism.

FIG. 4 is a flowchart showing an operation example of mold clamping force detection processing.

FIG. 5 is a diagram showing an example of a mold clamping force display screen of a vertical injection molding machine that has been subjected to the method of the present invention.

FIG. 6 is a block diagram showing a control system for mold clamping adjustment and mold thickness adjustment of a conventional injection molding machine.

[Explanation of symbols]

 12 toggle position detector 21 operation switch 22 display unit 23 teaching unit 29 storage unit 41 conversion unit 42 calculation unit 43 comparison unit 44 conversion table 110 movable platen 111 tie bar 210 machine control unit

Claims (1)

[Claims] 1. A movable platen is moved by driving a toggle mechanism by a servo motor to perform a mold clamping operation, and a movable platen is moved by a mold thickness adjusting motor to adjust a mold thickness and a mold clamping force. Toggle position detecting means for detecting a toggle position by a detector attached to the servo motor, movable platen position detecting means for detecting a movable platen position by a detector mechanically coupled to the movable platen, and the toggle position And a mold thickness setting means for setting the relationship between the movable platen position, and a mold clamping amount, which is a difference between the movable platen position after setting the mold thickness and the platen position converted from the toggle position. The mold clamping amount is calculated based on the mold clamping amount and displayed, and the mold clamping force is allowed. A method for displaying a mold clamping force in an injection molding machine, wherein a warning is displayed when the value exceeds the value.