JPS62160219A - Automatic mold thickness regulating device - Google Patents

Abstract

PURPOSE:To permit to regulate a mold thickness more correctly and more quickly by a method wherein the moving amount of a moving platen from the position of a crosshead to a position whereat a toggle mechanism is brought into the condition of lock-up is operated to retreat a rear platen and advance the moving platen. CONSTITUTION:The position of a crosshead is detected by a crosshead position detecting means C after attaching a mold to an injection molding machine and the mold is opened slightly by a toggle driving means A while a moving amount from the detected position of the crosshead to the lock-up condition of a moving platen is operated by a lock-up control means D to retreat a rear platen by the amount of movement and advance the moving platen to the lock-up condition thereof. Thereafter, a rear platen driving means B is driven to move the mold and when the mold is abutted thereon, a mold abutment detecting means E detects the abutment and a mold clamping force providing means F drives the rear platen driving means B after the detection to advance the rear platen by an amount corresponding to a mold clamping force and set the mold clamping force.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an automatic mold thickness adjustment device for a Tagawa molding machine having a toggle type mold clamping device.

With the conventional technology toggle type mold clamping device, when replacing the mold, the mold thickness adjustment operation must be performed to adjust the mold clamping force according to the thickness of the mold. Conventionally, operations were performed by operators based on their experience, but if the mold clamping force was too strong, too much force would be applied to the tie bars and there was a risk of cracking, and if it was too weak, the injection molding could not be done properly. .

Therefore, a %i setting that automatically adjusts the mold thickness was developed.
No. 2142), these devices move the rear platen with the toggle link fully extended, touch the mold, and then adjust the mold clamping force. That is, in these devices, the mold was opened, the toggle link was extended, the lock-up state was established, and the rear platen was moved to touch the mold to adjust the mold clamping force. However, in order to put the toggle mechanism into the lock-up state, that is, the toggle link is fully extended, the mold must be kept wide open so that the mold does not close even in the lock-up state. In a mold such as a three-piece mold that cannot be opened very far in order to prevent abnormal force from being applied to the mold, it is extremely difficult to control the lock-up state.

(Y) The position of the crosshead can be detected by a detector installed in the revo motor, but since the relationship between the position of the crosshead and the moving platen is non-linear, the movement of the crosshead is not the amount of movement of the moving platen. First, its control was complicated.

Problems to be Solved by the Invention The object of the present invention is to provide a mold thickness adjustment device for an injection molding machine that solves the above problems and allows mold thickness adjustment to be performed more accurately and more quickly.

Means for Solving the Problems Figure 1 shows means for solving the above problems according to the present invention.The present invention includes a toggle drive means Δ of a toggle mechanism for moving a moving platen, and a toggle drive means Δ for driving a rear platen along a tie bar. Rear platen driving means B, means C for detecting the position of the crosshead of the toggle mechanism, and calculation of the amount of movement of the moving platen from the crosshead position detected by the means C until the toggle mechanism reaches a fully extended lockup state. lock-up control means for driving the rear platen driving means B to move the rear platen backward by the amount of movement and driving the toggle driving means A to a lock-up state; and a mold contact detection means for detecting contact between the molds. means E, and a mold clamping force that drives the rear platen driving means B after lock-up by the lock-up control means and advances the rear platen by a set mold clamping force after the mold contact detection means E detects mold contact. The above problem was solved by providing the applying means F.

After installing the working mold to the injection molding machine, the toggle drive means A
After slightly opening the mold, the crosshead position is detected by the crosshead position detection means C, and from the detected crosshead position, the lockup control means calculates the amount of movement of the moving platen to the lockup state. The rear platen is moved backward and the moving platen is moved forward by the amount of movement to bring it into a lock-up state. Thereafter, the rear platen drive means B is driven to move the mold, and when the molds come into contact, the mold contact means E detects the contact, and after that detection, the mold clamping force applying means F is activated by the rear platen drive means. Drive B to move the rear platen to 111' by the mold clamping force.
Set the mold clamping force by incrementing i.

Embodiment FIG. 2 is a diagram showing the structure of a mold clamp 1 in an embodiment of the present invention, FIG. 3 is a diagram showing the configuration of a control section in the same embodiment, and FIG. 4 is a diagram showing the operation of the same embodiment. Processing flowchart, fifth
The figure is a crosshead transfer! FIG. 6 is an explanatory diagram for determining the amount of movement of the moving platen with respect to IIm.

In FIG. 2, one mold 1 is attached to a front platen 2, and the other mold 3 is attached to a moving platen 4. ) O seat platen 2 has four tie bars 5
A rear platen 6 is provided at the other end of each tie bar 5, and two sets of toggle mechanisms 8.8 are provided between the rear platen 6 and the moving platen 4.
The toggle mechanism 8.8 has the same structure and is symmetrical with respect to the axis of a ball screw 9, which will be described later, and has pins P1.8 on the moving platen 4. Pi and the first link 12.12 rotatably fixed to the rear platen 6. A second link 13.1 in the form of an abbreviation rotatably fixed at P2
3 and crosshead 10 with bottle P3. A third link 14.14 is rotatably fixed to the pin P3, and the first link 12.12 and the second link 13.13 are attached to the pin P4
．． The second link 13.13 and the third link 14.14 are rotatably fixed at the pin P5.
It is fixed so that it can rotate freely. Also, cross head 10
is fixed with a bolt or the like to a pole nut 11 that is screwed into a ball screw 9, and the ball screw 9 is fixed to a bearing portion 1 fixed to a through hole provided in the center of the rear platen 6.
5, and is fixed to a motor shaft 17 of a toggle drive servo motor M6 by a connecting portion 16.

Nuts 18 are provided on the back side of the rear platen 6 to be engaged with screws cut into each tie bar 5, and a sprocket 19 is fixed onto the nuts 18.
A collar 20 is fixed to the rear platen 6 at the other end of the collar 20 so as to engage with the flange-like portion.

The sprocket 19 is a sprocket that is fixed to the rear platen 6 via a support member 23 or provided on the shaft of a servo motor Ma for moving the ablate platen.

It is driven by a chain (not shown), and as the sprockets 19 rotate, the nut 18 fixed to one of the sprockets rotates, and the collar 20. By pressing the rear platen 6, the rear platen 6 is moved from side to side in FIG.

In addition, 21 is a hole through which the tie bar 5 provided on the rear platen 6 is passed, and 22 is a toggle drive servo motor Ml)
24 is a bearing, Pa, which is fixed to the rear platen 6.

Pb is a servo motor Ma for moving the rear platen.

This is a position detector such as a pulse encoder provided on the servo motor Mb for toggle driving.

The mold clamping mechanism is configured as described above, and the rear platen 6 is moved by the drive of the servo motor Ma as described above.
The moving platen 4 is a toggle drive servo motor Mb.
By driving the two ball screws, the pole nut 11 screwed into the ball screw 9 is moved from side to side in FIG.
The cross head 10 fixed to the cross head 10 is moved left and right, and the toggle mechanism 8.8' is driven to slide the cross head 10 on the tie bar 5 left and right in FIG.

FIG. 3 is a block diagram of the main parts of the control section of an automatic mold thickness adjustment device according to an embodiment of the present invention, and 30 is a numerical control device (hereinafter referred to as CNC) having a computer as a control means for controlling the mold clamping device. ), 40a is a servo circuit for a servo motor Ma for driving the rear platen, and 40b is a servo circuit for a servo motor Mb for toggle driving. In the CNC 50, 31 is a central processing unit (hereinafter referred to as CPU), and 32 is a ROM that stores a control program for controlling the injection molding chamber.
33 is a servo interface; 33 is a servo interface; 33 is a servo interface; Through the servo interface 33, the servo circuit 40a,
It outputs position commands to the error registers 41a and 41b of the error registers 40b and reads the values of the error registers 41a and 41b. 34 is a manual input device for inputting various commands and various setting values.

Note that 35 is a bus.

40a and 40b are known servo circuits, and these servo circuits 4Qa and 40b have the same configuration, and a movement vJ command consisting of a pulse train is transmitted via the servo interface 33 of the CNC 50 as a unit time movement. When input, this movement command and encoders pa, p
The difference between the movement of the servo motors Ma and Mb detected in step b is calculated by error registers 4'la and 41b, and the difference is calculated by a digital-to-analog converter (hereinafter referred to as a D/A converter).
At 428° 42b, it is converted into an analog suspension voltage as a speed command value. Furthermore, this servo circuit performs speed feedback in order to improve responsiveness, and this means that signals from encoders Pa and Pb are transferred to F/V converter 43a,
43b converts it into a voltage, subtracts the voltage corresponding to the actual speed of the servo motor from the speed command value, and the difference, that is, the error between the command speed and the actual speed, is amplified by compensators 44a and 44b to generate torque. Output as a command. This torque command is output as a voltage corresponding to the current value flowing through the armatures of the servo motors Ma and Mb, and in response to this torque command, torque limit circuits 48a and 48b are used to limit the output torque of the servo motors. In order to further improve the responsiveness to the outputs of the torque limit circuits 48a and 48b, the current detectors 47a and 47b detect armature currents of the servo motors Ma and Mb. The voltage is fed back, and the difference between the torque command and the armature current feedback signal is amplified by compensators 45a and 45b, and power amplifiers 46a and 46
b is amplified to drive and control the servo motor Ma1Mb. Note that 49a and 49b are D/A converters that convert the torque limit command value from the CNC 50 into an analog signal and apply it to the torque limit circuits 48a and 48b.

As described above, the servo circuits 46a and 46b operate, but the values of the error registers 41a and 41b of each servo circuit 40a and 40b are determined by the servo interface 33.
is input, and the CNC 50 is designed to be able to detect an error.

Servo motor Mb transfer 8 suspension (rotating mother) and crosshead 1
0's movement ω+fil, the movement amount of the servo motor Ma, and the movement amount of the rear platen 6 are in a proportional relationship, but the movement amount of the crosshead 10 and the movement amount of the moving platen 4 are nonlinear due to the presence of the toggle mechanism 8.8'. In a relationship. Next, the relationship between the amount of movement of the crosshead 10 and the amount of movement of the moving platen 4 will be determined.

As shown in FIG. 5, the bin P on the moving platen 4
1, the distance between the bin 24 at the connection point of the first link 12 and the second link 13, that is, the length of the link 12, is d1 The distance between the bin P2 on the rear platen 6 and the bin 24 is b
1 The distance between bin P2 and bin 25 is C, the distance between bin P5 and bin 13 on the crosshead 10 is e, and the vertical distance between bin P2 and bin 13 on Figures 2 and 3 is h. shall be.

FIG. 5(a) shows the state in which the links of the 1-group Ml 4M 8 are fully extended (hereinafter referred to as the lock-up state), and the horizontal distance between the bins P2 and P3 at this time is defined as y. That is, when the crosshead 10 is in the lock-up state, the distance in the left-right direction of the bin P2 on the rear platen 6 in FIGS. 2 and 3 is y.
This is an eigenvalue of the I-geometry, and is a constant 1 axis depending on the mold clamping mechanism.

Therefore, when the cross head 10 moves and the no-ping platen 4 is moved by X, the amount of movement Yc of the cross head 10 is calculated as shown in the following equation (1) as shown in Figure 5 (b). become.

Yc = y-1-yl + 'l'...
...(1) Then, if we find the straight line of y', y' = c-cos (π-(B10)) = -c-
cos(3+θ) ・・・・・・(2) For VLJ, Yuy = [e' −rl+ −c −5in (π−(
B+θ))'2]2 soil=[c'-(1+-c-'sin ([3+717)
)′! 1′! -----...(3) d2=a'+(a+d
-x )' -2a (a0d -x)cosθ
Therefore, B= arc −cos ((a'+c'-b2)/(
2ac))・・・・・・(5) From the above, Y= y 1 y' + y''
top = y-c-c
os (B+θ)+[e'-(h-c-sin (
3+θ))2]2 The moving platen 4 can be moved by this equation (6)! Crosshead 10 for 7Jf2tx
We were able to introduce a conversion formula for the movement of Yc.

Next, when finding the conversion formula from the movement @YC of the crosshead 10 to the movement amount of the moving platen 4, a' + c
2- b'a' + (a + d - x )
2-d 'CO3-' + CO3”□
±×2 8 C2a (a-)-d-X)...
...(7) By substituting it into equation (6), 1 Yc=y-c-cosX+[e2(h-c-sinX)
2]' -...(8) From equation (8), ('y'c-y+c-cosX)2=e'-(h-c-
sinX>2...(9) Decompose equation (9) to (YC-V)2+2C-CO3X・(YC-V)+02
-cos2X= e2- h' + 2h c sin
X −c2sin 2X −・・−(1
0) Rearranging equation (10), 2c (Yc-y)cosX-2hcsinX=e2-
h'-c'-(Yc-y)'... (11) Therefore, e2-h2-c'-(Yc-y)2 (YC-y) CO3X-h sin X= ---
--------C ・・・・・・(12) From the addition theorem, the left side of equation (12) is C ・・・・・・(13) From equation (12), e'-h2-c'- (Yc-y)'...<14) On the other hand, by transforming equation (7) and setting it as P as in equation (16), a'2+ (a, +d -x) 2-62
a' + c'2- b2cos-'
=X-cos-' = P2
a (a+d-x) 2 a c・
......(16) Therefore, a' + (a + d - x )' - σ2 = cosP 2a (a + d - x ) ...... (17) From equation (17), a2 + (a + d - x )'-d'= 2acosp(a
+d-x) ・-...-(18) Therefore (a+d-x)2-2acosP(a+d-x)+aQ
-d2...-(19) Considering (a + d -x) as a variable and solving the quadratic equation of equation (19), a2+ c2- b' P = X -cos-'□ a C ・...(22) Also, from equation (15), equation (22) becomes a2+ c2-
b' (23) From equation (24) above, a conversion equation is derived from the movement amount YC of the crosshead 10 to the movement 1FJIffi x of the moving platen 4.

Therefore, the CPU 31 calculates the equations (6) and (24).
By programming the mold thickness according to the present invention, the mold thickness can be adjusted accurately.

In addition, in the above equations (6) and (24), the values of a, b, c, d, e, and y as parameters are machine-specific values and are set for each machine. .

Next, based on the operation flowchart shown in FIG. 3, the mold thickness adjustment operation for controlling the nuts will be explained.

After the molds 1 and 3 are attached to the front platen 2 and the moving platen 4 and the molds 1 and 3 are closed, the mold clamping force is set using the manual operation input device 34 and a mold thickness adjustment command is input. For the CPU 31, the rear platen 6 is constant both L1
A pulse is outputted via the servo interface 33 to move the rear platen 6 backward by a certain amount ff1L1 (for example, 5 mm) (step 8).
1).

Next, the current position YC of the servo motor Mb for toggle drive
is read and it is determined whether the value is zero (step 82
). Note that the position of the crosshead when the toggle mechanism 8 is in the lock-up state, that is, the position of the servo motor Mb, is the origin, and this point is set as "0". If the visibility value YC of the servo motor Mb is not rl, the movement ix of the moving platen 4 with respect to the current value Yc is obtained by performing a calculation using the equation (24) (step S3). and,
In step S, it is determined whether the calculated value of the movement vJffix of the moving platen 4 is smaller than the constant ff1L1.
4) If the movement fix is larger than the constant 1fiL1, the value obtained by subtracting σ by the constant ff1L1 from the movement ■× is stored in the register as the new movement interval X (step S5).

Next, as described above, move the rear platen 6 back by a certain amount (
Step S6), the moving platen 4 is set at a constant ff1L.
It is advanced by 1 (step S7). That is, to move the moving platen 4 by a fixed amount of 1fiL1, calculate by substituting Ll for X in equation (6), and move the toggle drive servo motor Mb by the calculated current value valve Yc of the crosshead 10. The pulses equal to the number of pulses are output to the servo circuit 40b via the servo interface 33 (step S7). Then, the process returns to step $4 again, and the processes from step S4 to step 87 are repeated until the movement lx stored in the register becomes equal to or less than a certain amount of 11.

From this step 4 to step S7, glue abratin 6
The operation of moving the moving platen 4 backward by a fixed amount of ff1L1 and moving the moving platen 4 forward by a fixed amount of ff1L1 is done to prevent the molds 1 and 3 from coming into contact with each other, and also to prevent the molds 1 and 3 from coming into contact with each other when there are three molds.
This is to prevent the mold from being destroyed by opening too much. In this way, when the amount of movement X becomes equal to or less than a certain amount 11, the process proceeds to step S8, where the rear platen 6 is moved backward by the amount of movement x, and then the toggle drive servo motor Mb is driven until the toggle mechanism 8 is locked up ( Step 39). Next, the servo motor Mb for toggle drive
Read the current value of and judge whether the current value is "0" or not (step S2).Since the lockup is performed, the current value is "0".
Therefore, the process proceeds to step S10, where the servo motor Ma is driven at low torque while applying a torque limit by the torque limit circuit 48a, and the rear platen 6 is moved forward.

In other words, the toggle link of the toggle mechanism 8 is fully extended and in the locked-up state, the rear platen 6 moves forward, and the moving platen 4 also moves forward.Therefore, the CPU 31 reads the value of the error register 41a and makes sure that the value exceeds a certain value of 0. (Step 511). When the molds 1 and 3 come into contact and the moving platen 4 and rear platen 6 stop moving forward, ■ Despite the movement command being input to the cooler register 41a, the encoder Since the feedback signal from the servo motor Ma is not input and is not subtracted, the value of the error register 41a increases (note that the value of the servo motor Ma
(Since the torque is limited by the torque limit circuit 48a and the torque above a certain level is not output, the molds 1 and 3 are not pressed with a pressure below a certain level.) As a result, when the value of the error register 41a becomes equal to or higher than the fixed value Q, it means that the mold 1.3 has come into contact with the mold 1.3, so the movement of the rear platen 6 is stopped (step Sl 2), and then the servo motor for toggle drive is activated. The rear platen 6 is moved forward by an amount corresponding to the set mold clamping force (step 514). In other words, since the mold clamping force is generated by the extension of the tie bars 5, the rear platen is moved from the position of the rear platen 6 where the molds 1 and 3 come into contact when the toggle mechanism is locked up by an amount corresponding to the mold clamping force. If the mold is moved forward, the set mold clamping force will be increased by 1q. This completes the mold thickness adjustment operation.

11. There is no limit to the opening degree of the mold instead of a 3-piece mold etc.
), the processing from steps S4 to 87 is not necessary, and the rear platen 6 is moved back by the locked-out movement fix, and if the toggle machine (14 is driven) to the lock-up state, 4J is reached.

Effects of the Invention As stated above, the present invention is capable of moving the moving platen from the position of the crosshead until the toggle mechanism is in the lock-up state! Since n is calculated as 0, if you move the rear platen backward by the calculated amount and move the moving platen forward, the distance between the molds will not change, and the molds will accidentally come into contact with each other when adjusting the mold thickness. Since no large force is applied, mold thickness can be adjusted more accurately and quickly.

In addition, even if the mold cannot be opened wide, such as in a three-piece mold, the relationship between the amount of movement of the crosshead and the amount of movement of the moving platen is calculated, so the moving platen can be moved by a certain amount more accurately. Mold thickness can be adjusted quickly without destroying the mold.

[Brief explanation of drawings]

FIG. 1 is a block diagram of means for solving the problems of the prior art according to the present invention, FIG. 2 is a diagram showing a mold clamping mechanism of an embodiment of the present invention, and FIG. 3 is a diagram of the same embodiment. A block diagram of the main parts of the control section, FIG. 4 is an operation processing flowchart of the same embodiment,
FIG. 5 is an explanatory diagram for determining the amount of movement of the moving platen relative to the amount of movement of the crosshead. 1.3... Mold, 4... Moving platen, 5...
... Tie bar, 6... Rear platen, 8... Toggle mechanism, 9... Ball screw, 10... Cross head, Ma, Mb... Servo motor, 30... Numerical control 2Il device, 40a , 40b... Servo circuit, Pa, Pb... Encoder. Figure 1 Figure 4

Claims (2)

[Claims] (1) Toggle drive means of a toggle mechanism that moves the moving platen, rear platen drive means that drives the rear platen along the tie bar, means that detects the position of the crosshead of the toggle mechanism, and the crosshead detected by the means. Calculate the amount of movement of the moving platen from the position until the toggle mechanism reaches the lock-up state, and
lock-up control means for driving the rear platen driving means to move the rear platen backward by the amount of movement and driving the toggle driving means to a lock-up state; mold contact detection means for detecting contact of the mold; and mold clamping force applying means for driving the rear platen driving means after lockup by the lockup control means and advancing the rear platen by a set mold clamping force after the mold contact detection means detects mold contact. An automatic mold thickness adjustment device characterized by: (2) When the amount of movement exceeds a certain value, the lock-up control means moves the rear platen backward by the certain amount until it becomes less than the certain value, and also moves the moving platen forward by the certain amount. The automatic mold thickness adjusting device according to claim 1, wherein the head is brought into a lock-up state by repeating an operation of advancing the head.