JPH035265B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention makes it possible to automatically adjust the die height according to various molds in injection molding equipment such as a die casting machine or an injection molding machine, and to adjust the die height according to a desired mold. This invention relates to a die height/mold clamping force adjustment device that enables automatic setting of clamping force.

[Conventional technology]

Generally, in this type of injection molding equipment, a fixed mold fixed to a fixed platen and a movable mold fixed to a movable platen are butted against each other, and both are clamped with a large force to apply a predetermined mold clamping force. Molten metal is injected into a mold cavity to perform molding.

In such injection molding equipment, the molds are replaced as appropriate depending on the type of molded product.
When replacing the mold, the distance between the fixed platen and the movable platen, that is, the die height, is adjusted as appropriate depending on the thickness of the mold. This die height adjustment is usually done by visual measurement by the operator. After retracting the movable platen an appropriate distance, the toggle mechanism for opening the mold clamping mold is fully extended, and the movable platen is moved at a constant speed. The movable mold and the fixed mold are brought into contact with each other, and the operator confirms the point of contact visually and by feeling, and sets it as the die height adjustment position.

After adjusting the die height, the movable platen is advanced to adjust the mold clamping force.
Generally, the mold clamping force is adjusted based on the actual mold clamping force detected by a mold clamping force detector (hereinafter referred to as a load meter) installed in the device.
The operator judges whether the desired mold clamping force is too much or too little.
The movable platen is moved forward or backward as appropriate to set the mold clamping force to a desired value.

[Problem that the invention seeks to solve]

However, with the die height adjustment method described above, there is a high possibility that an extremely large error will occur between the die height adjustment position set by the operator and the true die height adjustment position. In other words, the true die height adjustment position is the delicate point at which the movable mold and the fixed mold make a soft touch, and the work of confirming this soft touch point visually and by feeling must rely on the intuition of a skilled worker. I didn't get it. If an average worker attempts to perform this work, the movable mold must be stopped far in front of the fixed mold, or the movable mold must be stopped before the movable mold contacts the fixed mold. This caused the problem that the die height adjustment position was set while the die was in strong contact with the fixed mold.

Further, the moving speed of the movable platen is generally set to be high, and the impact force when the movable mold advances at such a speed and the fixed mold come into contact is extremely large. In other words, as the time when the movable mold stops is delayed from the above-mentioned soft touch point, the impact force increases, and there is a risk of damaging not only the mold but also the injection molding apparatus itself.

On the other hand, the method for adjusting the mold clamping force described above has the problem that it requires labor from the operator each time the mold clamping force is set to a desired value, which is extremely troublesome.

[Means for solving problems]

The present invention has been made in view of these points, and includes a die height detector that detects the die height interval, and a die height detection value L' detected by the die height detector and a die height detection value L' that is set in advance according to the mold to be installed. If it is determined that L'> L, α (predetermined value) + L and
When L' is in the range of L'>L+α, the die height spacing is rapidly decreased, and L'=
When L+α and within the range of L′≦L+α, the die height spacing is decreased slowly, and when it is determined that L′<L, the die height spacing is rapidly increased until L′=L+α, L′=L
The die height is adjusted by slowly decreasing the die height interval from the point when +α is reached, and after adjusting the die height, the expected mold clamping force is calculated from the expected mold clamping coefficient C ₁ and the desired mold clamping force F, and this prediction The mold is first clamped using the mold clamping force, and the error λ' of F' with respect to F is determined from the actual mold clamping force F' and the desired mold clamping force, and this λ' is compared with the allowable error λ. When it is determined that λ'≧, the actual mold clamping coefficient C' is calculated from the above C ₁ , F and F', the corrected mold clamping force is calculated based on this C', and this corrected mold clamping force is The mold is clamped again using a mold clamping force that is the sum of the above-mentioned predicted mold clamping force.

[Effect]

Therefore, according to the present invention, after rapidly decreasing or increasing, the die height interval can be brought close to the set value L while decreasing at a very slow speed.

Further, according to the present invention, after adjusting the die height, once the mold is clamped with the aim of achieving, for example, 95% of the desired mold clamping force F, the actual mold clamping force is determined based on the generated mold clamping force F'. The mold clamping force can be automatically adjusted so that it matches the desired mold clamping force F.

〔Example〕

Hereinafter, the die height/mold clamping force adjusting device according to the present invention will be explained in detail. FIG. 2 is a front view showing an example of an injection molding apparatus equipped with this die height/mold clamping force adjusting device, and FIG. 3 is a left side view of FIG. 2. In the figure, 1 is a fixed platen, 2 is a movable platen, and 3 is a link housing. The fixed platen 1 has a fixed mold 1a, and the movable platen 2 has a movable mold 2a.
It is attached using 8,18. Reference numeral 4 denotes a plurality of columns (usually four columns) arranged parallel to each other, and both ends of the columns 4 are fixed by column nuts 5 on the outside of the fixed platen 1 and the link housing 3. 6 is the mold clamping cylinder, 7
Reference numeral 8 indicates a toggle mechanism, and 8 indicates a machine base, in which the link housing 3 can be slid along the column 4 by turning a column nut 5 on the link housing 3 side. A chain foil 5a is attached to the circumferential surface of the column nut 5 rotatably attached to the link housing 3.
An endless chain 1 is formed between the chain wheel 5a and the chain wheel 9a fixed to the output shaft of the die height motor 9.
0 is wound around the column nut 5, and by rotating the die height motor 9 forward or reverse, the column nut 5
By rotating the link housing 3, the link housing 3 can be moved forward to the right or backward to the left in FIG. That is, column 4
The natural length l can be adjusted as appropriate.

The mold clamping cylinder 6 is fixed to the link housing 3, and a toggle mechanism 7 is expanded and contracted via a piston rod 6a installed in the mold clamping cylinder 6 to move the movable platen 2 fitted to the column 4 to the fixed platen 1. It is now possible to approach or retreat. The illustrated state shows a state in which the toggle mechanism 7 is fully tensioned, that is, the piston rod 6a of the mold clamping cylinder 6 is fully extended, and the movable mold 2a and the fixed mold 1a are brought into close contact. Normally, in such a state, the movable mold 2a and the fixed mold 1a are in a state where they are pressed together (mold clamped) with a predetermined pressure (mold clamping force). , movable mold 2a
The explanation will proceed assuming that the fixed mold 1a and the fixed mold 1a are in a soft touch state (mold clamping force is zero) in this state. That is, the mold thickness T ₁ is the sum of the movable mold 2a and the fixed mold 1a, and the thickness of the movable platen 2 and the fixed platen 1 when the toggle mechanism 7 is fully tensioned without the molds 2a and 1a installed. It is assumed that the interval (die height) L _M is set to be approximately equal, and therefore no clamping force is applied to the movable mold 2a and the fixed mold 1a, that is, a soft touch state is established. .

On the other hand, the machine base 8 has the die height
A die height detector 11 for detecting L _M is attached, and this die height detector 11
The die height L _M can be detected with an accuracy of 1 micron via a die height detection bar 11a fixed to the link housing 3. That is, in this injection molding apparatus,
Toggle mechanism 7 without installing molds 2a and 1a
The distance (minimum die height) Ls between the movable platen 2 and the fixed platen 1 after moving the link housing 3 with the link housing fully tensioned and bringing the movable platen 2 as close as possible to the fixed platen 1 side is determined by the machine specifications. The distance _l1 between the link housing 3 and the movable platen 2 at this time (with the toggle mechanism 7 fully tensioned) is also a fixed value determined based on the machine specifications. Mold 2a and 1
The die height L _M when a is installed is expressed as Ls (minimum die height) + ΔL. Therefore, the distance l between the link housing 3 and the fixed platen 1 is l = l ₁
+Ls+ΔL. As mentioned above, l ₁ +Ls is a fixed value determined by the machine specifications, and if ΔL is detected with this l ₁ +Ls as the zero reference position, that is, if the movement amount ΔL of the link housing 3 is detected, the die height L _M can be calculated. That is, the die height detector 11 is capable of detecting this ΔL via the die height detection bar 11a, and is composed of a pulse generator that generates a pulse signal according to this ΔL.

In addition, the link housing 3 includes a toggle mechanism 7.
A mold opening/closing stroke position detector 12 is attached to detect the stroke position of the movable platen 2 ( _l1 is the maximum stroke position), and the stroke detection bar 1 fixed to the movable platen 2
Stroke position of movable platen 2 via 2a
It consists of a pulse generator that detects l' and generates a pulse signal according to this stroke position.

Therefore, the die height adjusting device 1 as shown in FIG.
4 is connected. This die height adjustment device 1
4 has a control unit 15 which incorporates a microcomputer, and a signal corresponding to ΔL sent from the die height detector 11 is sent to the input terminal 15a of the control unit 15, and a signal corresponding to the mold opening/closing stroke position is sent to the input terminal 15b. Detector 12
A signal corresponding to l' sent out by is inputted. Further, the minimum die height dimension Ls determined by the machine specifications is input to the input terminal 15c, and the die height setting value L set in the die height setting device 16 is input to the input terminal 15d. This die height setting value L is set in the die height setting device 16 every time the mold is replaced, and is set appropriately to a value equal to the thickness of the mold that is about to be replaced. . Based on this input information, a microcomputer installed in the control unit 15 performs arithmetic processing and outputs appropriate output signals from the output terminals 15e to 15k. That is, the output signals sent from the output terminals 15e to 15k are transmitted to the die height motor 9 of the injection molding apparatus 13.
It is designed to be input to output terminal 15.
The output signals sent by the cylinders i and 15j are input to a hydraulic valve or the like 6b that controls the cylinder 6. Further, the output signal sent from the output terminal 15k is inputted to an abnormality warning device 17, which includes, for example, a buzzer or a display. Then, the die height motor 9 is rapidly rotated in the normal direction by the signal sent from the output terminal 15e, and the second
In the figure, the link housing 3 is fixed to the platen 1.
output terminal 15f.
The die height motor 9 is rapidly reversed by the signal sent by the link housing 3, and the link housing 3 is rapidly retreated. Further, the die height motor 9 rotates forward at a very low speed in response to a signal sent from the output terminal 15g, causing the link housing 3 to move forward at a very slow speed, and the die height motor 9 is stopped by a signal sent from the output terminal 15h, causing the link housing 3 to move forward at a very slow speed. movement is now stopped. Further, the cylinder 6 tensions the toggle mechanism 7 to advance the movable platen 2 toward the fixed platen 1 in response to a signal sent from the output terminal 15i, and retracts the toggle mechanism 7 in response to a signal sent from the output terminal 15j. The movable platen 2 is moved backward.

A die height adjustment program is stored in the microcomputer of the control unit 15 configured as described above, which makes it possible to automatically adjust the die height according to the mold to be replaced. FIG. 5 is a flowchart showing one embodiment of this die height adjustment program, and this die height adjustment program is started as appropriate after the replacement mold is carried in and arranged as described below. The input terminal 15l in FIG. 4 is a set terminal to which a start signal for starting this die height adjustment program is input.

Next, the arrangement of carrying in the replacement mold will be explained.
That is, in the injection molding apparatus 13 shown in FIG.
We will explain the process up to the time of loading and arranging between. When removing the molds 1a and 2a, as shown in FIG.
9 is placed below the fixed mold 1a and the movable mold 2a, and the clamp devices 18, 18 are unlocked. Then, the toggle mechanism 7 is retracted to move the movable platen 2 backward. With this, the movable mold 2a
remains on the roller 19a of the mold changing device 19 together with the fixed mold 1a. On the other hand, a flange portion 20a of a casting sleeve 20 for injecting molding material is protruded from the mold mounting surface side of the fixed platen 1.
However, the depression 1a ₁ formed on the back side of the fixed mold 1a
is fitted. Therefore, it is not possible to remove the molds 1a and 2a simply by retracting the movable platen 2. Therefore, as shown in FIG. 7, an embossing cylinder 21 built into the fixed platen 1 is used. That is, while pressing the fixed mold 1a in the direction of the arrow shown in the figure with the piston rod 21a of the embossing cylinder 21, the recessed part _1a1 of the fixed mold 1a is separated from the flange part 20a to be in a free state, and the molds 1a and Remove 1b.

After removing the molds 1a and 2a in this way, as shown in FIG. 8, the mold thickness T ₂
The replacement molds 1b and 2b are carried between the fixed platen 1 and the movable platen 2 via the mold changing device 19. This replacement mold is carried in with the movable platen 2 at a stroke position that is approximately 40% backward from the maximum stroke position, that is, with the distance between the link housing 3 and the movable platen 2 being l ₁ × 0.6, and the fixed mold A flange portion 20 protruding from the recessed portion 1b ₁ on the back side of the platen 1b to the mold mounting surface of the fixed platen 1.
Place it so that it faces a. In addition, the gap a ₁ between the fixed mold 1b and the fixed platen 1 at this time is set to a value larger than the protruding dimension a ₂ of the flange portion 20a of the casting sleeve 20 and smaller than the predetermined dimension α (a ₂ ＜a ₁ ＜α). In this example, this α
For example, let it be 10mm. In addition, when transporting the replacement mold,
The reason why the movable platen 2 is set back by 40% is to enable sufficient transport of even a mold corresponding to the maximum die height.

After the replacement molds 1b and 2b are placed between the fixed platen 1 and the movable platen 2, the mold thickness _T2 of the replacement molds is set in the die height setting device 16 shown in FIG. That is,
The mold thickness T ₂ is set as the die height setting value L of this mold. Then, a start signal is input to the set terminal 15l to start the die height adjustment program shown in FIG.

The operation of this die height adjustment program will be explained below with reference to FIGS. 4 and 8. Once you start this die height adjustment program (step 100), step 1
Die height setting value L and die height detection value at 01
L′ is compared. In other words, die height setting device 1
The set value L set to 6 and the die height detector 1
The detection value L' calculated from ΔL detected in step 1 is compared, and if L'>L, that is, the mold thickness shown in Fig. 8 is compared.
If T ₂ is smaller than the mold thickness T ₁ shown in Figure 2,
Proceed to step 102 and set the detected value L' and L (set value) +
α is compared. Here, as mentioned above, α is set to 10 mm in this example,
If L'>L+10, step 103 is executed, and as shown in FIG. 8, the toggle mechanism 7 is fully tensioned to move the movable platen 2 forward. And step 10
At step 4, the die height motor 9 is rapidly rotated forward, and the link housing 3 is rapidly advanced. As a result, the die height begins to narrow rapidly. and,
When L'+L+α is detected (step 105),
Execute step 106 until output terminal 15
The rapid advance signal sent from e was interrupted,
In place of this, a slow advance signal is sent from the output terminal 15g. In response to this signal, the die height motor 9 changes from the previous rapid normal rotation to a slow normal rotation state, and moves the link housing 3 forward at a slow speed. That is, after the detected value L' becomes equal to L (set value) + α, the die height is narrowed at a very slow speed.

On the other hand, if it is determined in step 102 that L'≦L+α, no output signal is sent from the output terminal 15f (step 107), the die height motor 9 is reversed, and the link housing 3 is moved backward. Then, in step 108, L'=
When L+α is detected, the die height motor 9 is stopped, and steps 103 and subsequent steps are executed in the same manner as described above.

In step 106, when the movable platen 2 is moved forward at a slow speed and the replacement mold is pressed, the fixed mold 1b finally comes into contact with the mold mounting surface of the fixed platen 1. Well, die height detection value
The value of L' becomes constant, and there is no change in the pulse signal sent by the die height detector 11. 109 is a step for detecting the presence or absence of a change in this pulse signal, and when there is no change in the pulse signal, it is detected in step 110 whether or not this state has continued for more than 1 second, and if the state has continued for more than 1 second, Step 1111 is executed, a stop signal is sent from the output terminal 15h, the die height motor 9 is stopped, and the fixed mold 1b and the movable mold 2b are moved to the fixed platen 1 and the movable platen 2 by the clamp devices 18, 18. It will be installed. If it is determined in step 112 that |L'-L|≦1, the toggle mechanism 7 is retracted to move the movable platen 2 backward (step 113). A stroke position detector of the movable platen 2 obtained by the signal sent from the mold opening/closing stroke position detector 12
When l' becomes l (maximum stroke) -5 (step 114), the retracting operation of the toggle mechanism 7 is stopped (step 115), and in step 116 the program returns to the main program. This step 113-11
The operation 5 is performed for adjusting the mold clamping force, which will be described later. In this way, when the thickness T ₂ of the replacement mold is smaller than the die height setting value at the time of replacement, that is, L _M ≈T ₁ in FIG. 2, the die height is automatically adjusted. In addition, the adjustment operation is skillfully performed such that it is rapid up to a predetermined position and then slowed down in consideration of damage to the mold and the like.

If it is determined in step 112 that |L'-L|>1, an abnormality signal is output from the output terminal 15k and the abnormality warning device 17 is activated (step 117). In other words, even though the die height detection value L' has become constant, |L'-L|>
1 means that there is a possibility of an abnormality, such as a foreign object being caught between the fixed mold 1b and the movable mold 2b, or the input value of the die height setting value L being incorrect. Therefore, assuming such an abnormal condition, a warning of the abnormal condition is issued in step 117.

In this embodiment, the toggle mechanism 7 is tensioned in step 103, but the toggle mechanism 7 is not tensioned here, and the link housing 3 is moved rapidly and slowly forward while the link housing 3 is in the contracted state. Another possible method is to stop the link housing 3 when L' becomes |L'-L|≦1, and then tension the toggle mechanism 7 from this state to adjust the die height. However, in this case, if there is a foreign object caught between the molds and the thickness of the mold is thicker than the set value L, the fixed mold 1b will be moved with the foreign object sandwiched between the molds. It comes into pressure contact with the fixed platen 1. If this contact force is extremely large and exceeds the allowable value, there is a risk that the column of the injection molding equipment may break or the platen may crack, creating an extremely dangerous situation. . Furthermore, a similar problem will occur if the set value L is mistakenly set to a small value. Furthermore, if the set value L is mistakenly set to a large value, the fixed mold 1b will not come into contact with the fixed platen 1, resulting in a problem that the mold will not be mounted. Therefore, it is not very preferable to adjust the die height by moving the link housing 3 forward while keeping the toggle mechanism 7 retracted.In step 103, the link housing 3 is moved forward with the toggle mechanism 7 tensioned. It is hoped that

On the other hand, if it is determined in step 101 that L'≦L, it is determined in step 118 whether L'<L, and if L'<L, the process moves to step 119 and the output terminal 15f is An output signal is sent, the die height motor 9 is rapidly reversed, and the link housing 3 is rapidly retreated. Then, in step 120
When L'=L+α is detected, the die height motor 9
stops (step 121), the toggle mechanism 7 is fully tensioned in step 122, and the process continues in step 1.
06 and subsequent steps are executed in the same manner as described above. By doing this, the thickness T ₂ of the replacement mold can be adjusted to the die height setting value at the time of replacement, that is, as shown in Fig. 2.
Even if L _M is larger than T ₁ , the die height is automatically adjusted. On the other hand, if it is determined in step 118 that L'≧L, the operation of this program is stopped in step 123.

Incidentally, in step 122, the toggle mechanism 7
The link housing 3 is moved forward at a very slow speed without being stretched, and the link housing 3 remains in the contracted state, so that the detected value L' becomes |L'-L
Although it is possible to adjust the die height by stopping the link housing 3 when |≦1 and tightening the toggle mechanism 7 from this state,
This is not very preferable because the same problems as mentioned above occur. In addition, in step 119, the pressure in the mold clamping cylinder 6 is detected without rapidly retracting the link housing 3, and the toggle mechanism 7 is gradually tightened to press the replacement mold and press the mold clamping cylinder 6.
When the pressure starts to rise suddenly, stop it in that state, move the link housing 3 back by a predetermined amount, tighten the toggle mechanism 7 again, detect the rise in pressure...
It is possible to adjust the die height by repeating this operation, but an accident such as a failure of the pressure detector that detects the pressure in the mold clamping cylinder 6 is assumed, and if this pressure detector fails, If the replacement mold is tightened with great force, there is a risk that not only the replacement mold but also the injection molding apparatus itself will be damaged. Therefore, adjustment by such a method is inappropriate.

Also, after performing step 119, |L'-L
A possible method is to stop the link housing 3 when it becomes ≦1, fully tension the toggle mechanism 7, and adjust the die height.
With this method, the impact of backlash caused by the column nut 5 when the mold is clamped will be reduced.
The difference will be different between the case of L'>L and the case of L', resulting in a problem that it will affect the setting of the mold clamping force, which will be described later. That is, Fig. 9 shows the threaded state of the column nut 5 to the column 4 when the link housing is adjusted while moving forward, and Fig. 10 shows the threaded state of the column nut 5 when the link housing is adjusted while moving backward. . That is, as is clear from the figure, the locking surface is different when the column nut 5 is stopped while moving forward and when it is stopped while moving backward. Therefore, when the column 4 tries to expand due to the clamping force acting on it, the amount of expansion differs, which adversely affects the setting of the clamping force. For this reason, in the case of L'<L, the link housing 3 is moved back once and then moved forward, so that the influence of backlash is the same as in the case of L'>L.

FIG. 1a is a schematic functional block diagram of the main operating parts of a microcomputer in which such a die height adjustment program is stored. In the figure, 22 receives the signals sent from the die height detector 11 and the die height setter 16, and calculates the detected die height value based on the minimum die height value Ls.
This is a first comparison circuit that calculates L' and compares this detected value L' with a die height setting value L. Further, 23 inputs the signals sent from the die height detector 11 and the die height setting device 16, calculates the die height detection value L', and compares this detection value L' with L (set value) + α (predetermined value). Similarly to the second comparator 23, 29 is a third comparison circuit that compares the detected value L' and L+α.

When the first comparison circuit 22 determines that L'>L, an output signal is sent from the output terminal 22a, this signal is held in the latch circuit 30, and is input to the second comparison circuit 23 as a set signal. ing. The second comparator 23 operates upon receiving this set signal and compares L+α and L'. When the second comparator 23 determines that L'>L+α, a rapid advance signal is sent from the output terminal 23a, the die height motor 9 rapidly rotates, and the link housing rapidly advances. When the link housing rapidly moves forward, the die height rapidly narrows and the die height detection value L' decreases. Then, in the second comparison circuit 23, L'≦L
When +α is reached, a slow advance signal is sent from the output terminal 23b, the die height motor 9 rotates at a slow speed, and the link housing moves forward at a slow speed. Of course, the second
Even when the comparison circuit 23 determines that L'≦L+α without rapidly advancing the link housing, a slow advance signal is sent from the output terminal 23b.

On the other hand, when the first comparison circuit 22 determines that L'<L, an output signal is sent from the output terminal 22b, held in the latch circuit 31, and sent to the die height motor 9 as a rapid retraction signal. . The die height motor 9 receives this signal and rotates rapidly, causing the link housing to retreat rapidly. Further, this rapid retraction signal is simultaneously inputted to the reset terminal 30a of the latch circuit 30 and the set terminal 29a of the third comparison circuit 29, and releases the holding of the set signal in the latch circuit 30, and activates the third comparison circuit 29. let When the third comparison circuit 29 determines that L'=L+α, a reset signal is sent from the output terminal 29b to the reset terminal 31a of the latch circuit 31, and the latch circuit 31 holds the rapid retraction signal. Release. With this, the die height motor 9
is stopped, and the operation of the third comparison circuit 29 is stopped.
At the same time, the reset state in the latch circuit 30 is also released, and since the relationship between L' and L at this time is L'=L+α, the second comparison circuit 23 is activated. Then, a minute advance signal is sent from the output terminal 23b, and the link housing moves forward slightly.
In this way, step 10 in FIG.
1,102,104,105,106,118,
119 and 120 are performed. In this functional block diagram, the die height detector 11 serves as die height detection means, the first comparison circuit 22 serves as die height comparison means, the second comparator 23 serves as first die height adjustment means, and the third comparison circuit 29 serves as die height comparison means. The die height adjustment means 2 constitutes the second die height adjusting means. Also, in this functional block diagram, the function of moving the link housing forward at a very slow speed and then stopping it when L'≈L is not shown, but steps 109 to 11 are not shown.
Needless to say, it has functions corresponding to 1.
This stopping of the link housing is not necessarily limited to the method according to steps 109 to 111,
Other methods may be used as long as L'=L can be detected.

Further, in this embodiment, a pulse generator is used as the die height detector 11, but a linear scale potentiometer may also be used, or a detector using another method may be used as long as the die height dimension can be detected. It's okay. Further, although the predetermined value α has been described as being stored in advance in the microcomputer, it may be set as appropriate from outside.

In addition, if you only want to adjust the die height, please use the fifth
Although it is possible to sufficiently achieve the purpose up to step 112 in the flowchart in the figure, by using steps 113 to 115, the toggle mechanism 7 is degenerated by β with respect to the maximum stroke _l1, as shown in FIG. By stopping the mold in this state, the mold clamping force can be automatically adjusted as described below.

A mold clamping force adjustment device that enables automatic adjustment of mold clamping force will be described below. FIG. 12 is a schematic diagram showing an embodiment of this mold clamping force adjusting device, and the same reference numerals as in FIG. 4 indicate the same parts. This mold clamping force adjustment device 24 has a control unit 25 that includes a microcomputer, and a signal corresponding to ΔL sent from the die height detector 11 is sent to an input terminal 25a of the control unit.
A mold opening/closing stroke position detector 1 is connected to the input terminal 25b.
A signal corresponding to l' sent out by No. 2 is input. Further, a signal corresponding to the actual mold clamping force F' sent out by the load meter 26 is input to the input terminal 25c, and a signal corresponding to the actual mold clamping force F' sent out from the load meter 26 is input to the input terminal 25d.
, the desired mold clamping force F set in the mold clamping force setting device 27
is now being entered. Incidentally, the load meter 26 is attached to the column 4 as shown in FIG. 2, and is adapted to send out a signal corresponding to the actual mold clamping force based on the amount of extension of the column 4. The desired mold clamping force F is an optimal mold clamping force that takes into consideration the type of mold, molding conditions, etc., and can be set in advance from the outside before operating the mold clamping force adjustment device 24. Further, a signal corresponding to an expected mold clamping coefficient C ₁ , which will be described later, is inputted to the input terminal 25e via a mold clamping coefficient setter 28. Then, based on this input information, a microcomputer installed in the control unit 25 performs arithmetic processing, and outputs the output terminals 25f to 25j.
The output signal is sent out more appropriately.
That is, the signal sent from the output terminal 25f causes the die height motor 9 to rotate in the forward direction to advance the link housing 3 toward the fixed platen 1 in FIG. 11, and the signal sent from the output terminal 25g causes the die height motor 9 to rotate forward. 9 is reversed to move the link housing 3 backward, and the die height motor 9 is stopped by a signal sent from the output terminal 25h, thereby stopping the movement of the link housing 3. In addition, the output terminal 25i
The mold clamping cylinder 6 tensions the toggle mechanism 7 to advance the movable platen 2 toward the fixed platen 1, and the signal transmitted from the output terminal 25j causes the mold clamping cylinder 6 to retract the toggle mechanism 7 and move the movable platen. 2 is set to move backwards.

Next, the above-mentioned expected mold clamping coefficient _C1 will be explained. That is, the injection molding apparatus 13 in FIG.
(soft touch state with zero mold clamping force), when the column nut 5 is rotated and the link housing 3 is advanced, the movable platen 2 is moved between the molds 1a and 2a.
This pressing force causes the column 4 to expand, and the force by which the column 4 tries to restore its original shape becomes mold clamping force. Then, this mold clamping force F′ is measured by the load meter 2
6 is used for detection. By the way, this mold clamping force
In order to make F' match the desired mold clamping force F, it is necessary to further move the link housing 3 by Δδ ₀ . This Δδ ₀ is expressed as Δδ ₀ =C·(F−F′) (1). That is, C in this equation is a true mold clamping coefficient, which is a proportionality constant determined by the rigidity of the column 4, link housing 3, movable platen 2, fixed platen 1, etc. If Δδ ₀ obtained in this way is positive, the link housing 3 is moved forward by Δδ ₀ , and if it is negative, it is moved backward by Δδ ₀ , so that the mold clamping force F' matches the desired mold clamping force F. be able to.

However, it is extremely difficult to determine this true mold clamping coefficient C in advance. In other words, the extension Δl ₁ of the column 4 is calculated as follows: Δl ₁ = F'・l ₂ /A・E (2) where the length of the column 4 under tension is l ₂ (Figure 2). However, A: The cross-sectional area of the column, E: can be determined by Young's modulus. In this equation, F' is the mold clamping force at that time, and in order to make F' match the desired mold clamping force F using only the rigidity of the column 4, it is sufficient to move the link housing 3 by Δδ ₁ . Here, Δδ ₁ is expressed by the following equation.

Δδ ₁ =F・l ₂ /A・E−F′・l ₂ /A・E = l ₂ /A・E・(F−F′) ……(3) The length l ₂ of column 4 is As is clear from Figure 2, it is expressed as l ₂ =l _a +l ₁ +L _M +l _b (4). In this formula, l _a , l ₁ , and l _b are fixed values determined by machine specifications, and L _M is a value approximately equal to the thickness T ₁ of the mold. Therefore,
If only the mold thickness T ₁ is given, the amount of movement Δδ ₁ due to the rigidity of the column 4 can be found relatively easily.

However, the actual Δδ ₀ includes the above Δδ ₁ and the distortion Δδ ₂ due to the rigidity of the mold, platens, etc., and the distortion Δδ ₂ of the mold, platens, etc. cannot be determined so easily. . For example, in the case of a platen, it is greatly affected by the dimensions of the mold, W and H, and the rigidity of the mold (FIG. 13). As shown in Figures 14 a to c, the load conditions on the platen also vary depending on the rigidity of the mold, whether it is close to a uniformly distributed load, a partial load, or a concentrated load at two points above and below. come. That is, the distortion of the platen varies greatly depending on the mold, and it is difficult to determine this distortion in advance.

In other words, it is extremely difficult to determine the true mold clamping coefficient C in advance according to many types of molds, and for this reason, the predicted mold clamping coefficient C is aimed at 95% of the true mold clamping coefficient C. ₁ and set it in the mold clamping coefficient setter 28 shown in FIG. This mold clamping factor
C ₁ can be easily determined based on the above formula (1).

On the other hand, the mold clamping force adjusting device 2 configured as described above
A mold clamping force adjustment program is stored in the microcomputer installed in the control unit 25 of No. 4, which automatically makes it possible to adjust the desired mold clamping force according to the mold to be installed. FIG. 15 is a flowchart showing an embodiment of this mold clamping force adjustment program. After setting the above-mentioned expected mold clamping coefficient C ₁ , the toggle mechanism 7 as shown in FIG.
It is designed to start in a degenerated state. That is, the movable mold 2b and the fixed mold 1b
This mold clamping force adjustment program is started by inputting a start signal to the set terminal 25k of the control unit 25 shown in FIG. 12 with a gap .beta. In this embodiment, β is set to 5 mm.

Below, the operation of this mold clamping force adjustment program will be explained as follows.
This will be explained with reference to FIGS. 1 and 12. That is, when this mold clamping force adjustment program starts (step 200), the link housing 3 begins to move forward in step 201. and,
In step 202, the expected extension amount Δl of the column is calculated from the expected mold clamping coefficient C ₁ and the desired mold clamping force F (Δl=C ₁ ×F), and compared with the forward movement amount Δl' of the link housing 3. When Δl' becomes equal to Δl, the forward movement of the link housing 3 is stopped (step 203). That is, the movable mold 2b moves forward by Δl and stops at the position indicated by the dotted line in FIG. 11. From this state, the toggle mechanism 7 is fully tensioned to clamp the mold (step 20).
4). Then, the mold clamping force F′ at this time and the desired mold clamping force F
From, |F−F′|/F is calculated, and the allowable error rate λ
(0.05 in this embodiment) (step 205). That is, calculate the error λ'=|F-F'|/F between the actual mold clamping force F' and the desired mold clamping force F, and if this error λ' is 0.05 (5%) or less,
Assuming that F' matches F, the toggle mechanism 7 is fully retracted (steps 207 to 209), and the program returns to the main program (step 210). still,
After executing step 205, Δl' at this time is stored in step 206.

On the other hand, when it is determined in step 205 that |F-F'|/F≧λ, the actual mold clamping coefficient C' is calculated and stored in step 211, and then
The toggle mechanism 7 retracts (step 212).
The arithmetic expression for C' in step 211 is expressed as follows.

C'= _C1 /2F-F'×F...(5) In other words, the movement amount Δδ of the link housing 3 to be corrected is Δδ=Δl'-Δl=(C'- _C1 )・F=C'・(F-F')...(6) Therefore, C' is determined by _C1 /2F-F'×F. Then, in step 212, the toggle mechanism 7 is retracted, and the stroke position of the movable platen 2 is
When l ₁ ' becomes l ₁ '≦l ₁ - β (step 213), the retracting operation of the toggle mechanism 7 stops, and (step 2
14) The die height detection value L' at this time is stored in L1 (step 215), and the die height detection value L' at this time is stored in _L1 (step 215).
In step 217, Δδ is calculated, Δδ=C′·(F−F′), and whether this Δδ is positive or negative is determined. Then, in this step 217, Δδ is positive (Δδ>
0), the link housing 3 is advanced (step 218), and the actual Δδ' is determined from the _L1 and the L' that is being detected (step 220).
When Δδ′=Δδ, the process returns to step 203.
Stop the link housing 3 and follow step 2.
Execute steps 04 and later again. On the other hand, step 217
If it is determined that Δδ≦0, the link housing 3 is moved backward (step 219), and in the same way, when Δδ′ = Δδ in step 220, the process returns to step 203 and the link housing 3 is stopped. , execute steps 204 and subsequent steps again. That is, in step 204, mold clamping is performed again with the link housing 3 moved by Δδ further than Δl. This operation is performed in step 20.
5, the process is automatically repeated until λ'<λ.

In this way, the mold clamping force is automatically adjusted with an error of 5% relative to the desired mold clamping force F. still,
It goes without saying that the tolerance λ does not necessarily have to be 5% and may be set even smaller.
Δl' and C' stored in step 206 and step 211 can be used as Δl and _C1 when adjusting the clamping force of the same mold next time. That is, it is sufficient to store Δl' and C' in correspondence with the mounting mold, and by doing so, the processing time in this program can be shortened.

By the way, FIG. 1b is a schematic functional block diagram of the main operating parts of a microcomputer in which such a mold clamping force adjustment program is stored. In the same figure, 32 is a signal corresponding to the expected mold clamping coefficient C ₁ sent by the mold clamping coefficient setter 28 and a mold clamping force setter 2.
7, the expected elongation amount Δl of the column is calculated, and this Δl
There is a Δl calculation circuit which sends a signal corresponding to the die height motor 9 to move the link housing 3 forward as shown in FIG. Further, 33 is a signal corresponding to the actual mold clamping force F' sent out by the load meter 26,
The signal corresponding to the mold clamping force F sent out by the mold clamping force setter 27 is input, and the error λ' of F' with respect to F is calculated.
This is an error comparison circuit that compares this λ' and the allowable error λ. This error comparison circuit 33 is configured to send a die height motor stop signal to the die height motor 9 from the output terminal 33a when λ'<λ, and λ'≧λ
At this time, a set signal is sent to the C' calculation circuit 34 from the output terminal 33b. Further, the C' calculation circuit 34 is activated by this set signal, and the above-mentioned (5)
The Δδ calculation circuit 35 calculates Δδ from the signal corresponding to C′ and the signals corresponding to F and F′ (Δδ=C′・(F−F′)). There is.
In this Δδ calculation circuit 35, Δδ>0
If so, the output terminal 35a outputs a signal to the die height motor 9 to advance the link housing by an amount corresponding to Δδ, and if Δδ≦0, the output terminal 35b outputs a signal to advance the link housing by an amount corresponding to Δδ. A signal is output to the die height motor 9 to cause the die height motor 9 to move backward. In such a functional block diagram, the Δl calculation circuit 32 functions as the first mold clamping means for clamping the mold with the expected mold clamping force, the error comparison circuit 33 functions as the error comparison means, and the C' calculation circuit 3
4 and the Δδ calculation circuit 35 constitute a second mold clamping means for clamping the mold with a mold clamping force that is the sum of the corrected mold clamping force and the expected mold clamping force.

Incidentally, a mold clamping force check program as shown in the flowchart of FIG. 16 may be added after step 209 in the flowchart shown in FIG. 15. That is, in step 221,
The toggle mechanism is tensioned to perform mold clamping, and this mold clamping operation is repeated five times (step 225), and the mold clamping forces F ₁ ' to F ₅ ' each time are memorized (step 2
22, 223). Then, the maximum value and the minimum value are deleted from the mold clamping forces F ₁ ' to F ₅ ' (step 226), and the average value of the remaining mold clamping forces is calculated (step 227). Then, in step 228, the error between the average mold clamping force Fn' and the desired mold clamping force F is λn'=
Find |F−Fn′|/F, compare it with the tolerance ε (0.05 in this example), and if λn′<ε,
Step 2 assuming that the mold clamping force is within the tolerance
21 and subsequent steps are repeated again. If it is determined in this step 228 that λn'≧ε, the first
After step 211 and subsequent steps in FIG.
The following actions are performed. In other words, an injection molding machine equipped with such a program can automatically adjust the mold clamping force optimally, and can
The mold clamping force is automatically checked once per shot, and if the error in the mold clamping force exceeds the allowable value, the mold clamping force is adjusted as appropriate to an appropriate value.
Continue molding operations without any problems.

Furthermore, as shown in FIG. 17, before the C' calculation in step 211, a step 229 is provided to compare the maximum allowable mold clamping force value Fmax and the detected mold clamping force value L', and in this step 229, F'≧ When it is determined that Fmax is reached, the mold may be opened, C' = C ₁ ×0.5 (step 234), Δδ calculated, and the link housing may be moved back to reset the mold clamping force. That is, by doing so, it is possible to prevent accidents such as damage to the device due to excessive mold clamping force. Incidentally, the coefficient in step 234 is
The value is not limited to 0.5, and may be any other value as long as the mold clamping force can be reset to a smaller value. In addition, in this example, the expected mold clamping coefficient C ₁ was set with the aim of being 95% of the true mold clamping coefficient C, but it goes without saying that it is not limited to 95%, and the closer it is to 100%, the better. stomach.

〔Effect of the invention〕

As explained above, according to the present invention, the die height detection value L′ and the die height setting value L are compared,
If L'>L, compare α (predetermined value) + L and L',
When L'>L+α, the die height interval is rapidly decreased, and when L'=L+α and L'≦L+α, the die height interval is decreased slowly, and L'<L in the case of,
The die height is adjusted by rapidly increasing the die height interval until L' = L + α, and then decreasing the die height interval at a slight speed from the point when L' = L + α, so the die height can be adjusted according to the mold. It is now possible to automatically perform the adjustment, and the adjustment can be done quickly at a predetermined position, and then at a slow speed in consideration of damage to the mold, etc. The die height can be adjusted accurately and quickly without relying on the feeling of a skilled worker.

Further, according to the present invention, after adjusting the die height, the expected mold clamping force is calculated from the expected mold clamping coefficient C ₁ and the desired mold clamping force F, and the mold is first clamped using this predicted mold clamping force. From mold clamping force F′ and desired mold clamping force F
Find the error λ' of F' with respect to F, compare this λ' with the allowable error λ, and when it is determined that λ'≧λ, the above
The actual mold clamping coefficient C' was calculated from C', F, and F', the corrected mold clamping force was calculated based on this C', and this corrected mold clamping force and the predicted mold clamping force were summed. Since the mold is clamped again using the mold clamping force, the actual mold clamping force can be automatically adjusted to match the desired mold clamping force, and the mold clamping force can be adjusted quickly and accurately.

[Brief explanation of drawings]

FIG. 1a is a schematic functional block diagram of the main operating parts of a microcomputer in which a die height adjustment program is stored in an embodiment of the die height/mold clamping force adjusting device according to the present invention, and FIG. 1b is a die height and mold clamping force adjusting device according to the present invention. - A schematic functional block diagram of the main operating parts of the microcomputer in which the mold clamping force adjustment program is stored in one embodiment of the mold clamping force adjustment device. Figure 2 shows an injection molding machine equipped with this die height/mold clamping force adjustment device. A front view showing an example, FIG. 3 is a left side view of this injection molding device in FIG. 2, FIG. 4 is a schematic configuration diagram of a die height adjustment device installed in this injection molding device, and FIG. A flowchart showing the die height adjustment program stored in the microcomputer of the device, FIGS. 6 to 8 are side views illustrating the method of replacing molds in the injection molding device, and FIGS. 9 and 10 are columns using column nuts. FIG. 11 is a schematic side view showing the state of the injection molding apparatus at the time when the operation of the die height adjustment program is completed; FIG.
The figure is a schematic configuration diagram of a mold clamping force adjustment device that automatically adjusts the mold clamping force after the operation of the die height adjustment program is completed, and Figure 13 is an external perspective view showing the state of the mold mounted on the platen. Figure 14 a, b, c
is a side view showing an example of the load acting on the platen, Fig. 15 is a flowchart showing the mold clamping force adjustment program stored in the microcomputer of the mold clamping force adjustment device, and Fig. 16 is the mold clamping force adjustment program. FIG. 17 is a flowchart showing another embodiment of this mold clamping force adjustment program. 9... Die height motor, 11... Die height detector, 12... Mold opening/closing stroke position detector,
14...Die height adjustment device, 15...Control unit, 16...Die height setting device, 22
...First comparison circuit, 23...Second comparison circuit, 29
...Third comparison circuit, 24...Mold clamping force adjustment device, 2
5...Control unit, 26...Load meter, 27...Mold clamping force setter, 28...Mold clamping coefficient setter, 32...Δl calculation circuit, 33...Error comparison circuit, 34...C' calculation Circuit, 35...Δδ calculation circuit.

Claims (1)

[Claims] 1. Die height detection means for detecting the die height interval, and die height detection means for comparing the die height detection value L' detected by the die height detection means with the die height setting value L set according to the mold to be mounted. When L'>L is determined by the die height comparison means, α (predetermined value) +L is compared with L', and L'>L+
When in the range of α, the die height interval is rapidly decreased, and when L′=L+α and L′≦
a first die height adjusting means that slowly decreases the die height interval when the die height is in the range of L+α; and a first die height adjusting means that rapidly increases the die height interval until L′=L+α when the die height comparison means determines that L′<L; A die height adjusting means comprising a second die height adjusting means that decreases the die height spacing at a very slow speed from the time when the die height interval becomes equal to L+ _α ; A first mold clamping means that calculates an expected mold clamping force from the clamping force F and performs mold clamping with this expected mold clamping force, and an actual mold clamping when performing mold clamping with this first mold clamping means. an error comparing means for determining the error λ' of F' with respect to F from the force F' and the desired mold clamping force F and comparing it with the allowable error λ; and when the error comparing means determines that λ'≧λ, the C ₁ , the actual mold clamping coefficient from F and F′
A second mold clamping means calculates C', calculates a corrected mold clamping force based on this C', and performs mold clamping again with a mold clamping force that is the sum of this corrected mold clamping force and the predicted mold clamping force. A die height/mold clamping force adjusting device comprising a mold clamping force adjusting means comprising: