JP4964313B2 - Molding condition setting method and mold clamping device - Google Patents

Description

The present invention relates to a molding condition setting method, and more particularly to a molding condition setting method in a mold clamping apparatus using a toggle mechanism.

The mold apparatus generally includes a fixed mold and a movable mold, and the mold is closed, clamped, and opened by moving the movable mold forward and backward with respect to the fixed mold. The mold clamping device includes a fixed platen to which a fixed mold is attached, a movable platen to which a movable mold is attached, and a toggle mechanism that is a moving mechanism for moving the movable platen back and forth. That is, the mold mechanism is closed, clamped and opened by driving the toggle mechanism and moving the movable platen toward or away from the fixed platen (for example, Patent Document 1). reference.)
In the mold clamping apparatus as described above, when the mold is changed to have a different mold thickness, it is necessary to adjust the toggle mechanism so as to obtain an appropriate mold clamping force. More specifically, the position of the toggle support serving as the origin of the toggle mechanism is configured according to the mold thickness of the attached mold. The mold clamping device is provided with a mold thickness motor as a drive source for moving the toggle support. Accordingly, when the molds are replaced to have different mold thicknesses, the mold thickness motor is first driven to move the toggle support to an appropriate position as an adjustment operation of the mold clamping force.

More specifically, first, the mold clamping motor is driven to extend the toggle mechanism, and the movable platen is moved to the mold fully closed position. At this time, the toggle support is retracted to a position where the movable mold does not contact the fixed mold, that is, a position where the mold does not touch. Next, when the standard mold is used, the mold is opened by a distance to which a predetermined mold clamping force is applied. That is, the mold clamping motor is driven to move the movable platen backward by a distance where the mold clamping force setting value is applied. Then, while maintaining the state of the toggle mechanism, the mold thickness motor is driven to advance the toggle support until the movable mold comes into contact with the fixed mold, that is, until the mold touches. Thus, the adjustment of the toggle support position (referred to as mold thickness adjustment) at the time of mold replacement is completed.

When performing the above-described mold thickness adjustment, a mold touch is performed in which the toggle support is advanced in a state where the toggle mechanism is folded, and the movable mold is brought into contact with the fixed mold. At this time, the movable platen is moved closer to the fixed platen while moving the toggle support forward, and the forward movement of the toggle support is stopped when the die touch is made. Therefore, it is necessary to detect or determine that the mold has been touched, and stop the driving of the mold thickness motor that drives the toggle support at that time.

Conventional determination of the mold touch is performed by monitoring the torque of the mold thickness motor. That is, as shown in FIG. 1, when the output torque of the mold thickness motor is 100% and time has elapsed, it is determined that the mold touch has been made. FIG. 1 is a graph showing a change in output torque of a mold thickness motor when the mold thickness motor is driven at a constant voltage and the toggle support is advanced to touch the mold.

When the mold thickness motor is driven from the state in which the movable platen is away from the fixed platen to advance the toggle support, the movable platen connected to the toggle support by the toggle mechanism is also advanced at the same time, and is therefore attached to the movable platen. The movable mold also advances. When starting to move forward from the state where the toggle support is stopped, the output torque of the mold thickness motor rises to 100% momentarily in order to overcome the static friction at the sliding portion of the toggle support. Once the toggle support starts to move, the friction at the sliding portion of the toggle support becomes kinetic friction, so the output torque of the mold thickness motor decreases and becomes a constant value. The time when the output torque is constant indicates that the toggle support (that is, the movable mold) is moving forward.

Then, from the point of time when the movable mold advances and comes into contact with the fixed mold, the torque of the mold thickness motor starts to increase, finally increases to 100%, and then becomes constant at 100%. Conventionally, it has been determined that the mold touch has been completed by detecting that the torque of the mold thickness motor has become constant at 100%. That is, when the mold thickness motor continues to operate at an output torque of 100%, it is determined that the movable mold comes into contact with the fixed mold and the toggle support cannot advance further.

When performing the above-described mold thickness adjustment, a mold touch is performed in which the toggle support is advanced in a state where the toggle mechanism is folded, and the movable mold is brought into contact with the fixed mold. At this time, the movable platen is moved closer to the fixed platen while moving the toggle support forward, and the forward movement of the toggle support is stopped when the die touch is made. Therefore, it is necessary to detect or determine that the mold has been touched, and stop the driving of the mold thickness motor that drives the toggle support at that time.

Conventional determination of the mold touch is performed by monitoring the torque of the mold thickness motor. That is, as shown in FIG. 1, the output torque of the mold thickness motor becomes 100%, and it is determined that the mold is touched at a point T when a certain time has passed. FIG. 1 is a graph showing a change in output torque of a mold thickness motor when the mold thickness motor is driven and a toggle support is advanced to perform a mold touch.

When the mold thickness motor is driven from the state in which the movable platen is away from the fixed platen to advance the toggle support, the movable platen connected to the toggle support by the toggle mechanism is also advanced at the same time, and therefore is attached to the movable platen. The movable mold that has been moved forward. When starting to move forward from the state where the toggle support is stopped, the output torque of the mold thickness motor rises to 100% momentarily in order to overcome the static friction at the sliding portion of the toggle support. Once the toggle support starts to move, the friction at the sliding portion of the toggle support becomes kinetic friction, so the output torque of the mold thickness motor decreases and becomes a constant value. This indicates that the toggle support (that is, the movable mold) keeps moving forward for a fixed time of the output torque.

Then, from the point of time when the movable mold advances and comes into contact with the fixed mold, the torque of the mold thickness motor starts to increase, finally increases to 100%, and then becomes constant at 100%. Conventionally, it has been determined that the mold touch has been completed by detecting that the torque of the mold thickness motor has become constant at 100%. That is, when the mold thickness motor continues to operate at an output torque of 100%, it is determined that the movable mold comes into contact with the fixed mold and the toggle support cannot advance further.

JP 2002-337184 A

As described above, when the mold thickness adjustment is performed, when it is determined that the mold touch is completed because the output torque of the mold thickness motor is constant at 100%, the movable mold is pressed against the fixed mold. The toggle support stops at the position in the state. This state is a state in which a mold clamping force based on a pressing force according to the torque of the mold thickness motor has already been applied, and is not an accurate mold touch position where no mold clamping force is applied. The time when the die touch where the toggle support should be stopped is the time when the output torque of the die thickness motor starts to increase from a small constant value.

Therefore, when determining the mold touch based on the output torque of the mold thickness motor, the position of the toggle support is set to a position advanced from the position for obtaining a desired mold clamping force. As a result, the toggle mechanism is operated from the position advanced from the position where the main body toggle support should be stopped to apply the mold clamping force, and there is a problem that the desired mold clamping force cannot be applied with high accuracy. In particular, when it is necessary to control the mold clamping force with high accuracy, it is necessary to set the position of the toggle support with high accuracy, and in this respect, a technique capable of more accurately determining the mold touch is required. ing.

The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a molding condition setting method capable of stopping the toggle support at a desired position by accurately determining the type touch.

In order to achieve the above object, according to the present invention, there is provided a molding condition setting method applied to a mold clamping device using a toggle mechanism, wherein a toggle support is advanced in a mold closing direction, and a mold clamping force sensor is used. A molding condition setting method is provided , wherein after the touch of the movable mold and the fixed mold, the toggle support is stopped when the detected value reaches a threshold value. The mold clamping device uses a toggle mechanism, and after the mold touch between the mold thickness motor for moving the toggle support forward in the mold closing direction, the mold clamping force sensor, the movable mold and the fixed mold, the mold clamping is performed. And a control device that stops the toggle support when the detection value of the force sensor reaches a threshold value.

According to the above-described invention, since the mold touch is determined based on the detection value of the mold clamping sensor, the mold touch is more accurately compared to determining the mold touch based on the output torque of the mold thickness motor. Judgment can be made. Therefore, the toggle support can be accurately stopped at the desired position, and the mold clamping force can be controlled with high accuracy.

It is a graph which shows the change of the output torque of a mold thickness motor. It is a side view of the mold clamping apparatus of the molding machine with which the molding condition setting method by one embodiment of this invention is performed. It is a flowchart of a mold thickness adjustment process. It is a graph which shows the change of the detected value of the mold clamping force sensor used in order to judge a mold touch in a mold thickness adjustment process. It is a side view of a mold clamping device having a mold clamping force sensor attached to a movable platen. It is a side view of the mold clamping device which has the mold clamping force sensor attached to the toggle arm of a toggle mechanism.

  An embodiment of the present invention will be described with reference to the drawings.

FIG. 2 is a side view of a mold clamping device of a molding machine in which a molding condition setting method according to an embodiment of the present invention is performed. In FIG. 2, a mold clamping device 10 of an injection molding machine includes a frame 17 and a frame 1.
A fixed platen 12 as a fixed mold support device fixed to 7, and a toggle support 15 as a base plate disposed so as to be movable with respect to the frame 17 with a predetermined distance between the fixed platen 12. It has. The toggle support 15 functions as a toggle type mold clamping device support device. A plurality of (for example, four) tie bars 16 as guide means extend between the fixed platen 12 and the toggle support 15.

The movable platen 13 is disposed so as to face the fixed platen 12 and functions as a movable mold support device disposed so as to be capable of moving back and forth (moving in the horizontal direction in the drawing) along the tie bar 16. The mold apparatus 11 includes a fixed mold 11a and a movable mold 11b. The fixed mold 11 a is attached to a mold mounting surface of the fixed platen 12 that faces the movable platen 13. On the other hand, the movable mold 11 b is attached to a mold attachment surface of the movable platen 13 that faces the fixed platen 12.

A drive device for moving an ejector pin (not shown) may be attached to the rear end (left end in the figure) of the movable platen 13.

A toggle mechanism 20 as a toggle type mold clamping device is attached between the movable platen 13 and the toggle support 15. A mold clamping motor 26 as a mold clamping drive source for operating the toggle mechanism 20 is disposed at the rear end of the toggle support 15. The mold clamping motor 26 includes a motion direction conversion device (not shown) composed of a ball screw mechanism or the like that converts rotational motion into reciprocating motion, and the toggle mechanism 20 is moved forward and backward (moved in the horizontal direction in the figure) by moving the drive shaft 25 forward and backward. Can be operated. The mold clamping motor 26 is preferably a servo motor, and includes a mold opening / closing position sensor 27 as an encoder for detecting the number of rotations.

Here, the toggle mechanism 20 described above includes a cross head 24 attached to the drive shaft 25, a second toggle lever 23 attached to the cross head 24 so as to be swingable, and a toggle support 15.
The first toggle lever 21 is swingably attached to the movable platen 13, and the toggle arm 22 is swingably attached to the movable platen 13. Between the first toggle lever 21 and the second toggle lever 23 and between the first toggle lever 21 and the toggle arm 22 are linked. The toggle mechanism 20 is a so-called inner volume five-node double toggle mechanism, and has a vertically symmetrical configuration.

The toggle mechanism 20 can be operated by driving the mold clamping motor 26 and moving the cross head 24 as a driven member forward and backward. In this case, crosshead 2
When 4 is moved forward (moved in the right direction in the figure), the movable platen 13 is moved forward and the mold is closed. Then, a mold clamping force obtained by multiplying the propulsive force of the mold clamping motor 26 by the toggle magnification is generated, and the mold clamping is performed by the mold clamping force.

In addition, a mold clamping position adjusting device 35 is disposed at the rear end (left end in the drawing) of the toggle support 15 in order to adjust the position of the toggle support 15 with respect to the fixed platen 12. The toggle support 15 is formed with a plurality of, for example, four tie bar insertion holes (not shown), and the left end of the tie bar 16 in the figure is inserted into each tie bar insertion hole. The right end of the tie bar 16 is fixed to the fixed platen 12 by a fixing nut 16a.

The tie bar 16 has a screw portion 36 formed with a screw on the outer periphery at the left end in the figure, and an adjustment nut 37 is screwed to the screw portion 36 of each tie bar 16. The adjustment nut 37 is attached to the rear end of the toggle support 15 so as to be rotatable and immovable in the axial direction of the tie bar 16. A driven gear 37 a is attached to the outer periphery of the adjustment nut 37.

A mold thickness motor 31 as a mold clamping position adjusting drive source is disposed at an upper portion of the rear end of the toggle support 15. A driving gear 33 is attached to the rotation shaft of the mold thickness motor 31. Around the driven gear 37 a and the driving gear 33 of the adjustment nut 37, a chain,
A driving linear body 34 such as a toothed belt is wound around. Therefore, when the mold thickness motor 31 is driven and the driving gear 33 is rotated, the adjustment nuts 37 screwed into the screw portions 36 of the tie bars 16 are rotated in synchronization. Thereby, the mold thickness motor 31 can be rotated by a predetermined number of rotations in a predetermined direction, and the toggle support 15 can be advanced and retracted by a predetermined distance. The mold thickness motor 31 is preferably a servo motor, and includes a mold clamping position sensor 32 as an encoder that detects the number of rotations.

The means for transmitting the rotation of the mold thickness motor 31 to the adjusting nut 37 may be any means as long as the adjusting nut 37 screwed into the screw portion 36 of each tie bar 16 can be rotated synchronously. Good. For example, instead of the driving linear body 34, a large-diameter gear that meshes with all of the driving gear 33 and the driving gear 33 is rotatably disposed at the rear end of the toggle support 15. Also good.

In the mold clamping device shown in FIG. 2, a mold clamping force sensor 18 is disposed on one of the tie bars 16. The mold clamping force sensor 18 is a sensor that detects distortion (mainly elongation) of the tie bar 16. The tie bar 16 is applied with a tensile force corresponding to the mold clamping force during mold clamping, and extends slightly in proportion to the mold clamping force. Therefore, the mold clamping force actually applied to the mold apparatus 11 can be known by detecting the extension amount of the tie bar 16 by the mold clamping force sensor 18.

In the present embodiment, as will be described later, when performing mold thickness adjustment, a mold touch is determined using the mold clamping force detected by the mold clamping force sensor 18 and the operation of driving the mold thickness motor 31 is controlled. .

The above-described mold clamping force sensor 18, mold opening / closing position sensor 27, mold clamping motor 26, and mold thickness motor 31.
Is connected to the control device 19, and detection signals output from the mold clamping force sensor 18 and the mold opening / closing position sensor 27 are sent to the control device 19. The control device 19 performs the mold clamping motor 2 based on the detection signal.
6 and the mold thickness motor 31 are controlled.

Here, the operation of the mold clamping apparatus during normal molding will be described. When the mold clamping motor 26 is driven in the forward direction, the ball screw shaft 25 is rotated in the forward direction, and the ball screw shaft 25 is moved forward (moved in the right direction in FIG. 1) as shown in FIG. Accordingly, when the cross head 24 is moved forward and the toggle mechanism 20 is operated, the movable platen 13 is moved.
Is moved forward.

When the movable mold 11b attached to the movable platen 13 comes into contact with the fixed mold 11a (mold closed state), the mold clamping process is started. In the mold clamping process, the mold clamping force is generated in the mold 11 by the toggle mechanism 20 by further driving the mold clamping motor 26 in the forward direction.

And the injection drive part provided in the injection apparatus which is not shown in figure is driven, and a screw advances, The molten resin is filled in the cavity space formed in the metal mold | die 11. FIG. When opening the mold, when the mold clamping motor 26 is driven in the reverse direction, the ball screw shaft 25 is rotated in the reverse direction. Accordingly, when the cross head 24 is retracted and the toggle mechanism 20 is operated, the movable platen 13 is retracted.

When the mold opening process is completed, an ejector driving unit (not shown) is driven, and the ejector device attached to the movable platen is operated. Thereby, an ejector pin protrudes and the molded article in the movable mold 11b protrudes from the movable mold 11b. Simultaneously with the driving of the ejector driving unit, a molded product take-out machine as a gripping means (not shown) is driven, and the arm of the molded product take-out machine enters between the fixed mold 11a and the movable mold 11b, and takes out the molded product. Stop at position.
And the molded product protruded from the movable mold 11b by the advance of the ejector pin is held and taken out by the arm of the molded product take-out machine, and is conveyed to a conveyor device as a conveying means provided outside the injection molding machine. .

Next, a mold thickness adjusting method that is a molding condition setting method performed by the above-described mold clamping apparatus will be described. FIG. 3 is a flowchart of the mold thickness adjustment processing according to this embodiment. FIG. 4 is a graph showing a change in the detected value of the mold clamping force sensor used for determining the mold touch in the mold thickness adjusting method.

For example, when a mold apparatus 11 is newly attached to the mold clamping apparatus 10, a desired mold clamping force (target mold clamping force Z) is obtained at the set mold clamping force position (origin) as shown in FIG. It is necessary to adjust the mold clamping device 10 by performing mold thickness adjustment processing. The mold clamping device 10 is adjusted by changing the position of the toggle support 15 based on the thickness and rigidity (compression deformation amount) of the attached mold device 11. As described above, the fixed position of the toggle support 15 is adjusted by driving the mold thickness motor 31 and moving the toggle support 15 back and forth.

In the mold thickness adjustment process shown in FIG. 3, first, the mold clamping motor 26 is driven to extend the toggle mechanism 20, and the movable platen 13 is moved to the mold fully closed position (step S1). At this time, the toggle support 15 is positioned so that the movable mold 11b does not contact the fixed mold 11a.
That is, it is retracted to a position where the mold is not touched.

Next, the toggle mechanism 20 is operated to open the mold by a distance to which a predetermined mold clamping force is applied when the reference mold is used (step S2). That is, the mold clamping motor 26 is driven to move the movable platen 13 backward by a distance to which the mold clamping force set value is applied. The mold thickness motor 31 is driven to advance the toggle support 15 until the movable mold 11b comes into contact with the fixed mold 11a, that is, until the mold touches, while maintaining the state of the toggle mechanism 20 in the state of Step 2. (Step S3).

Next, the detection value of the mold clamping force sensor 18 is monitored to determine whether or not the detection value has reached a predetermined threshold value (step S4). If the detected value does not reach the predetermined threshold value, the determination process in step S4 is repeated. On the other hand, if it is determined in step S4 that the detected value has reached a predetermined threshold value, it is determined that the mold touch has been completed, the mold thickness motor 31 is stopped, and the forward movement of the toggle support 15 is stopped (step S5). ).

As shown in FIG. 4A, the detection value output from the mold clamping force sensor 18 does not rise from the time when the toggle support 15 starts to move forward (the origin of the graph), but when the mold is actually touched. It starts to rise from (A point). Accordingly, it may be determined that the mold touch is detected when the detection value starts to increase, but the detection value of the mold clamping force sensor 18 varies, and the detection value may slightly increase due to disturbance. There is. Therefore, in the present embodiment, a predetermined threshold value X is set in order to avoid erroneously determining an increase in the detection value due to disturbance as a type touch. That is, when the detection value output from the mold clamping force sensor 18 reaches a predetermined threshold value,
Judge that there was a mold touch.

FIG. 4B is a graph showing the output torque of the mold thickness motor, and has the same time axis as the graph of FIG. As is clear from comparison between FIG. 4A and FIG. 4B, the output torque of the mold thickness motor is determined by determining the mold touch based on the detection value of the mold clamping sensor (determination at point B). It can be seen that the mold touch can be determined at a time closer to the time when the mold touch is actually performed, as compared with the determination of the mold touch based on the determination (determination at the T point). That is, it is determined whether or not the mold touch is made more accurately when judging the mold touch based on the detection value of the mold clamping sensor than when judging the mold touch based on the output torque of the mold thickness motor. Can do.

As described above, according to the mold thickness adjusting method according to the present embodiment, it is possible to accurately determine that the mold has been touched, and it is possible to achieve more accurate control of the mold clamping force.

In the above-described example, the mold clamping force sensor 18 that detects the distortion of the tie bar 16 is used, but other mold clamping force sensors may be used as described below.

FIG. 5 is a side view of a mold clamping device having a mold clamping force sensor attached to the movable platen.
5, parts that are the same as the parts shown in FIG. 2 are given the same reference numerals, and descriptions thereof will be omitted.

The mold clamping force sensor 40 shown in FIG. 5 is a pressure sensor provided between the movable platen 13A and the movable platen support member 13B. The movable platen support member 13 </ b> B is connected to the toggle mechanism 20 and is moved by the toggle mechanism 20. Since the movable platen 13A is fixed to the movable platen support member 13B via the mold clamping force sensor 40, the movable platen 13A moves together with the movable platen support member 13B. The pressing force applied to the movable platen support member 13B is applied to the movable mold 11b via the mold clamping force sensor 40 and the movable platen 13A, and this pressing force becomes the mold clamping force. Therefore, the pressing force applied to the mold clamping force sensor 40 provided between the movable platen 13A and the movable platen support member 13B is the mold clamping force. By detecting this, the mold clamping force can be detected. it can. The detection value from the mold clamping force sensor 40 is supplied to the control device 19 and used for determination of the mold touch in the above-described mold thickness adjustment processing.

FIG. 6 is a side view of a mold clamping device having a mold clamping force sensor attached to a toggle arm of a toggle mechanism. 5, parts that are the same as the parts shown in FIG. 2 are given the same reference numerals, and descriptions thereof will be omitted.

A mold clamping sensor 41 shown in FIG. 6 is a strain sensor attached to the toggle arm 22, and detects a compressive strain and a bending strain due to a pressing force applied to the movable platen 13 via the toggle arm 22. The toggle arm 22 is a component that is easily elastically deformed by a pressing force applied to the movable platen 13, and a mold clamping sensor 41, which is a strain sensor, is attached to such a component so that the mold clamping force can be easily detected. it can. The detected value from the mold clamping force sensor 41 is the control device 1
9 and used for determination of the mold touch in the above-described mold thickness adjustment processing.

The place where the mold clamping force sensor 41 is attached is not limited to the toggle arm 22 and may be a portion that is elastically deformed by the pressing force generated by the toggle mechanism 20. For example, the mold clamping force sensor 41 may be attached to the first toggle lever 21 or the toggle support 15.

10 Mold clamping device 11 Mold device 12 Fixed platen 13, 13A Movable platen 13B Movable platen support member 15 Toggle support 16 Tie bar 18, 40, 41 Mold clamping force sensor 19 Control device 20 Toggle mechanism 26 Mold clamping motor 27 Mold opening / closing position sensor 31 Mold thickness motor 32 Mold clamping position sensor

Claims (2)

A molding condition setting method applied to a mold clamping device using a toggle mechanism,
Advance the toggle support in the mold closing direction,
Monitor the detection value from the mold clamping force sensor,
A molding condition setting method characterized by stopping toggle support when the detected value reaches a threshold value after touching the movable mold and the fixed mold . A mold clamping device using a toggle mechanism,
A mold thickness motor that advances the toggle support in the mold closing direction;
A mold clamping force sensor;
A control device for stopping the toggle support when the detection value of the mold clamping force sensor reaches a threshold value after touching the movable mold and the fixed mold;
A mold clamping device comprising:

Images