JP4727477B2 - Clamping force control method - Google Patents

Description

  The present invention relates to a mold clamping force control method, and more particularly to a mold clamping force control method for adjusting a mold clamping force generated by a mold clamping device.

  In an injection molding machine, mold clamping is generally performed by applying a mold clamping force generated by a mold clamping device to a mold, and molding is performed by injecting resin into the mold. In order to obtain the optimum clamping force, a method has been proposed in which the actual clamping force is detected by a sensor or the like, and the detected clamping force is fed back to the clamping process of the clamping device to control the clamping force. Yes.

  For example, it has storage means for storing the position of the moving member that moves the movable mold and the position of the generated mold clamping force, and the pattern of the mold clamping force obtained in advance and the detected mold clamping force Has been proposed (see, for example, Patent Document 1).

  Also, in the toggle type mold clamping device, the geometric positional relationship between the cross head and the movable platen is stored, and the mold clamping force obtained by the calculation by the calculator in the mold clamping process and the set mold clamping set by the setting device. It has been proposed to control by comparing the force (see, for example, Patent Document 2). This Patent Document 2 also proposes performing closed control for feedback control of the mold clamping force actually generated.

Further, it is proposed that when the mold clamping force reaches a plurality of predetermined values, the mold clamping position at each predetermined value is detected, and the correlation between the plurality of mold clamping forces and the mold clamping positions is stored. (For example, refer to Patent Document 3).
JP-A-11-277595 JP-A-8-281747 JP 2002-225102 A

  In the method of adjusting the mold clamping force by feedback control, the moving distance of a movable part (for example, a movable platen) that moves to clamp the mold and the magnitude of the mold clamping force that is generated when the movable part moves the moving distance. This relationship is preset. For example, when the actually detected clamping force is insufficient, the moving distance of the movable part is obtained based on a preset relationship so as to obtain a desired clamping force, and the movable part is clamped by the moving distance. Move in the direction. This moving distance of the movable part is referred to as a driving amount.

  The above-described preset relationship is usually a relationship obtained using a reference mold. However, there are a wide variety of molds that are actually used, and the thickness and rigidity of the mold are not the same as those of the reference mold. Therefore, the amount of distortion (compression deformation) of the reference mold when the reference mold is clamped with a certain clamping force is the mold when an actual mold different from the reference mold is clamped with the same clamping force. This is different from the amount of distortion. In other words, even if the movable platen is moved with the same driving amount, the generated clamping force changes due to the difference in mold thickness and rigidity characteristics.

  For example, even when using a mold that is less rigid than the reference mold, and adjusting the mold clamping force in the increasing direction, even if the movable part is moved by the driving amount based on the reference mold Since the mold having low rigidity is easily compressed and deformed, the desired mold clamping force is not reached.

  In this case, if feedback control is performed, the detected value of the mold clamping force indicates a result that the mold clamping force is still insufficient, and the adjustment of the driving amount is performed again. When such a readjustment is repeated several times to reach a desired mold clamping force, the feedback control for obtaining the desired mold clamping force ends.

  As described above, when the driving amount must be adjusted many times, there is a problem that it takes time to perform feedback control for adjusting the mold clamping force. In addition, if fine adjustment is repeatedly performed in a short time, a hunting phenomenon in which the mold clamping force vibrates without converging to the target value may occur in feedback control.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a mold clamping force control method that can perform mold clamping force adjustment in a short time even when a mold to be used is changed.

In order to achieve the above-described object, according to the present invention, by moving the movable part, the movable mold attached to the movable part is pressed against the fixed mold attached to the fixed part to clamp the mold. A mold clamping force control method of a mold clamping device for obtaining a mold, wherein a predetermined operation amount of the mold clamping device when a mold clamping force is generated by the mold clamping device is set, and the mold clamping force is set by the predetermined operation amount. The magnitude of the mold clamping force generated when the apparatus is driven is detected, the correspondence between the predetermined amount of operation and the detected magnitude of the mold clamping force is stored, and the mold clamping force is stored using the correspondence. And a mold clamping force control method characterized by using a moving amount of the movable platen as the operation amount .

Further, it is a mold clamping force control method for a mold clamping device that obtains a mold clamping force by pressing a movable mold attached to the movable part against a fixed mold attached to the fixed part by moving the movable part. A predetermined operation amount of the mold clamping device when the mold clamping force is generated by the mold clamping device is set, and the mold clamping force generated when the mold clamping device is driven by the predetermined operation amount is set. And the correspondence between the magnitude of the predetermined operation amount and the magnitude of the detected clamping force is stored, the clamping force is adjusted using the correspondence, and the clamping device uses a toggle mechanism. Thus, there is provided a mold clamping force control method characterized in that either one of a movement amount of a cross head of a toggle mechanism and a movement amount of a toggle support is used as the operation amount .

  According to the present invention, the mold clamping force is adjusted based on the rigidity characteristics of the mold to be used. Therefore, the mold rigidity characteristics can be reflected in the mold clamping force adjustment, and the mold clamping force can be efficiently and quickly performed. The target value can be reached.

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

  First, a mold clamping apparatus to which the mold clamping force control method according to the present invention can be applied will be described with reference to FIG. FIG. 1 is a side view of a mold clamping device to which a mold clamping force control method according to the present invention can be applied. The mold clamping apparatus shown in FIG. 1 is a toggle type mold clamping apparatus, and is used as a mold clamping apparatus of an injection molding machine.

  In FIG. 1, the mold clamping device 10 of the injection molding machine is movable with respect to the frame 17 with a predetermined distance between the frame 17, the fixed platen 12 fixed to the frame 17, and the fixed platen 12. And a toggle support 15 disposed. A plurality of (for example, four) tie bars 16 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 is disposed so as to be able to advance and retreat (move in the left-right 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 is attached between the movable platen 13 and the toggle support 15. A mold clamping motor 26 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 rotation speed.

  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 first toggle lever attached to the toggle support 15 so as to be swingable. 21 and a toggle arm 22 that 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 back and forth. In this case, when the cross head 24 is moved forward (moved in the right direction in the figure), the movable platen 13 is moved forward to perform mold closing. 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 order to adjust the position of the toggle support 15 with respect to the fixed platen 12, a mold clamping position adjusting device 35 is disposed at the rear end (left end in the figure) of the toggle support 15. 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 37a and the driving gear 33 of the adjustment nut 37, a driving linear body 34 such as a chain or 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.

  In the mold clamping apparatus shown in FIG. 1, 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 mold clamping apparatus shown in FIG. 1, a position sensor 40 that detects the amount of movement of the movable platen is attached to the movable platen 13. The position sensor 40 is composed of an optical or magnetic linear encoder, and reads the optical scale or magnetic scale 42 attached to the fixed platen 12 to detect the position of the movable platen 13 with respect to the fixed platen 12.

  The mold clamping force sensor 18, the mold opening / closing position sensor 27, the mold clamping motor 26, the mold thickness motor 31, and the position sensor 40 are connected to the control device 19, and the mold clamping force sensor 18, the mold opening / closing position sensor 27, and A detection signal output from the position sensor 40 is sent to the control device 19. The control device 19 controls the operations of the mold clamping motor 26 and the mold thickness motor 31 based on the detection signal. The mold clamping force control described later is also performed by the control device 19.

  Here, an operation 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 advanced and the toggle mechanism 20 is operated, the movable platen 13 is advanced.

  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, the ejector driving unit is driven, and the ejector device attached to the movable platen 13 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 drive of the ejector drive unit, a molded product take-out machine (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 stops at the molded product take-out 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. .

  By the way, the mold clamping force generated by the toggle mechanism 20 is the spring constant of the entire mold clamping device 10 including the fixed platen 12, the toggle support 15 and the tie bar 16, that is, as in the mold clamping device using a general toggle mechanism. The mold clamping rigidity changes as a proportional constant. In the mold clamping device 10, since the rigidity of the tie bar 16 is lower than that of other members, it can be considered that the mold clamping rigidity is equal to the rigidity of the tie bar 16. Therefore, the mold clamping force generated by the toggle mechanism 20 uses the spring constant as the stiffness of the tie bar 16 as a proportional constant, and the toggle support 15 moves relative to the fixed platen 12 from the mold closing of the mold clamping device 10 to the completion of mold clamping. It can be said that it changes in proportion to the amount to be done. That is, since the rigidity of the members such as the fixed platen 12 and the toggle support 15 is sufficiently high, the mold clamping force generated by the mold clamping device 10 is substantially generated by elastically deforming and extending the four tie bars 16. It can be said that it is proportional to the amount of elongation of the tie bar 16.

  However, when the tie bar 16 is elastically deformed and extended, the mold apparatus 11 itself is compressed and deformed by a mold clamping force. This amount of compressive deformation depends on the rigidity characteristics of the mold apparatus. Therefore, since the amount of compressive deformation of the mold apparatus changes when the mold apparatus is changed, the generated mold clamping force has a different value even when the tie bar 16 has the same expansion amount. In other words, in order to apply the same mold clamping force to the mold apparatus having different rigidity characteristics, it is necessary to make the extension amount of the tie bar 16 constant, so that the movable platen is considered in consideration of the amount of compressive deformation of the mold apparatus. It is necessary to control the position of 13 and make the amount of extension of the tie bar 16 constant. That is, it is necessary to control the amount of movement (that is, the driving amount) after the movable platen 13 touches the mold based on the rigidity characteristics of the mold apparatus to be used.

  Conventionally, it is assumed that the rigidity characteristics of the mold apparatus are substantially the same, and the amount of movement of the movable platen 13 (that is, the driving amount) is determined based on the rigidity characteristics of the reference mold. The error in the clamping force due to the difference in rigidity characteristics is feedback controlled until the desired clamping force is obtained using the actual clamping force detection value or the measured value corresponding to the actual clamping force. The mold clamping force was adjusted.

  Therefore, in one embodiment of the present invention, the actual rigidity characteristic of the mold apparatus is detected, and the amount of movement of the movable platen 13 (that is, the amount of thrust) is determined based on the obtained rigidity characteristic and a target value of the desired mold clamping force. To decide. Thus, theoretically, a desired mold clamping force can be obtained by driving the movable platen 13 by the determined driving amount without feedback control of the mold clamping force.

  However, because the mold clamping force varies due to factors other than the rigidity characteristics of the mold apparatus, feedback control is performed to bring the actual mold clamping force closer to the target value. Even in this case, the influence of the rigidity characteristics of the mold equipment, which is a major factor in the variation in mold clamping force, is eliminated, so the value is close to the target value of the mold clamping force from the beginning. Value can be reached.

  Here, as described above, the method of determining the driving amount based on the actual rigidity characteristic of the mold apparatus is referred to as auto-tuning. The auto tuning will be described in more detail with reference to FIG. FIG. 2 is a diagram showing the relationship between the amount of driving and the clamping force when auto-tuning is performed and when it is not performed.

  In FIG. 2, line A indicates the mold clamping force obtained with respect to the driving amount set when auto-tuning is not performed. That is, line A represents the clamping force obtained by compressing the reference mold and corresponds to the rigidity characteristic of the reference mold. On the other hand, in FIG. 2, line B shows the mold clamping force obtained with respect to the driving amount set when auto-tuning is performed. That is, the line B represents the clamping force obtained by compressing the actual mold, and corresponds to the rigidity characteristic of the actual mold. Therefore, the slopes of line A and line B represent the elastic modulus of the reference mold and the actual elastic coefficient of the mold, respectively.

  When auto-tuning is not performed, when the target value of the mold clamping force is set, the driving amount is obtained from the relationship indicated by the line A obtained based on the reference mold. In this case, the driving amount is a as shown in FIG. Therefore, when the movable platen 13 is actually moved (driven) from the mold closing position by the driving amount a, the mold clamping force reaches the target value if the rigidity characteristic is the reference mold indicated by the line A. Since the mold has a rigidity characteristic of line B, the actual mold clamping force is c.

  Therefore, auto tuning is performed to obtain the actual mold rigidity characteristic (line B), and the amount of driving is determined. That is, the driving amount b with respect to the target value of the mold clamping force is obtained from the relationship indicated by the line B. If the movable platen 13 is driven by this driving amount b, the mold clamping force becomes the target value. However, as described above, an error may be caused by factors other than the mold rigidity characteristics in the mold clamping force that is actually generated. Therefore, the mold clamping force can be generated with high accuracy by removing this error by feedback control. preferable.

  The above-mentioned rigidity characteristic (correspondence between the mold clamping force indicated by the lines A and B and the drive-in amount) is obtained from at least two different drive-up amounts and the detected values of the mold clamping force detected corresponding thereto. be able to. Assuming that the rigidity characteristic is linear, the rigidity characteristic can be determined by taking at least two points.

  Next, the configuration of the mold clamping force control system according to the present embodiment will be described with reference to FIG. FIG. 3 is a diagram showing a model of the mold clamping force control system according to the present embodiment.

  In FIG. 3, a setting value and a detection value of the mold clamping force are given to the node 50. The set value of the mold clamping force is a value of a desired mold clamping force input from the outside, and is a target value of the mold clamping force. The detected value of the mold clamping force is, for example, a value obtained by detecting the actual mold clamping force output from the mold clamping force sensor 18 shown in FIG. Then, the difference between the set value of the mold clamping force and the detected value is given to the correction unit 52 from the node 50. The correction unit 52 determines the driving amount based on the rigidity characteristic K obtained from the actual mold, that is, the rigidity characteristic K that varies depending on the mold used. Then, the mold clamping motor 26 of the mold clamping mechanism 54 is driven based on the driving amount determined by the correction unit 52, and the movable platen 13 is moved by the driving amount via the toggle mechanism 20.

  When the movement of the movable platen 13 is completed, the detected value of the mold clamping force is given to the node 50 again. If there is still a difference between the set value of the mold clamping force and the detected value, the driving amount is determined again and the movable platen 13 is moved. The mold clamping force control is completed when the difference between the set value of the mold clamping force and the detected value disappears or falls within a predetermined range by repeating such an operation. As described above, the mold clamping force control system of the present embodiment performs feedback control using the detected value of the mold clamping force.

  FIG. 4 is a diagram illustrating changes in the detected value of the clamping force when auto-tuning is performed and when it is not performed. In FIG. 4, line A indicates the mold clamping force obtained with respect to the driving amount set when auto-tuning is not performed. That is, line A represents the clamping force obtained by compressing the reference mold and corresponds to the rigidity characteristic of the reference mold. On the other hand, in FIG. 4, line B indicates the mold clamping force obtained with respect to the driving amount set when auto-tuning is performed. That is, the line B represents the clamping force obtained by compressing the actual mold, and corresponds to the rigidity characteristic of the actual mold.

  The origin of the graph in FIG. 4 corresponds to the detected value of the mold clamping force at the time when the mold clamping force is first generated. That is, the mold clamping force is set to a target value, the amount of driving is first determined, and the mold clamping force and the position of the moved movable platen 13 when the movable platen 13 is moved based on the amount of driving are shown in FIG. 4 is the origin of the graph. Therefore, in the example of the line A in the graph of FIG. 4, since the mold clamping force did not reach the target value in the first operation, the detected value of the mold clamping force at that time is fed back, and the mold clamping force is further controlled. It has been broken.

  When the auto-tuning according to the present embodiment is not performed, the mold rigidity characteristic K remains the same as that of the reference mold in the correction unit 52 in FIG. 3, and the mold clamping force changes along the line A in FIG. Will be.

  In FIG. 4, numbers (1), (2), and (3) on the line A indicate the order in which the detection values of the mold clamping force are obtained. The force is larger than the target value, and is smaller than the target value again in the second adjustment, indicating that the target value has been reached in the third adjustment. In other words, when auto-tuning is not performed, the actual mold rigidity characteristics are smaller than the reference mold rigidity characteristics. Therefore, even if an actual required driving amount is set, it is actually based on the rigidity characteristics indicated by line A. The amount of change is larger than the required amount of change in mold clamping force, the target value is exceeded by the first driving amount a, and the target value is passed by the driving amount determined by the second adjustment, The target value is almost reached by the third adjustment.

  On the other hand, when performing auto-tuning according to the present embodiment, the rigidity characteristic K of the mold is changed to the actual rigidity characteristic of the mold in the correction unit 52 in FIG. 3, and the mold clamping is performed along the line B in FIG. The power will change. In FIG. 4, the number 1 on the line B indicates the order in which the detected values of the clamping force are obtained, and indicates that the target value has been reached by the first adjustment.

  As described above, according to the mold clamping force control according to the present embodiment, when the mold clamping force is adjusted by feedback control, the mold clamping force can be brought close to the target value quickly by adjusting a small number of times. Good mold clamping force can be adjusted in a short time.

  The above-described mold clamping force control is performed as a preparatory stage before the mold is exchanged, and the data indicating the rigidity characteristic K of the obtained mold is stored in the memory or the like while the mold is used. It is good also as using the rigidity characteristic K currently hold | maintained at the memory | storage means, and being hold | maintained at the memory | storage means at the time of shaping | molding. The change in mold clamping force in this case is shown in FIG. FIG. 5A shows a change in mold clamping force when auto tuning is not performed, and FIG. 5B shows a change in mold clamping force when auto tuning is performed.

  Note that the adjustment of the mold clamping force shown in FIG. 5 is an example in which the mold clamping force is adjusted when the molded product is trial hit, and the adjustment is performed for each shot of the molded product. In this case, the rigidity characteristic of the mold is obtained in the mold clamping process before the first shot of the molded product or in the first shot (first shot), and the obtained rigidity characteristic value is used thereafter. Alternatively, the rigidity characteristic may be obtained for each shot and used for adjustment in the next shot.

  When auto-tuning is not performed, as shown in FIG. 5A, the mold clamping force gradually approaches the target value from the second shot, and almost reaches the target value at the sixth shot. On the other hand, when auto-tuning is performed, as shown in FIG. 5B, it is very close to the target value in the second shot and almost reaches the target value in the third shot.

  As described above, even when the auto-tuning according to the present embodiment is performed in the preparation stage before the molding is performed by exchanging the mold, the mold clamping force can reach the target value in a short time with a small number of shots. .

  Further, as described above, the auto-tuning according to the present embodiment may be continuously performed in the mold clamping process of each shot in the actual molding process.

  As described above, in the mold clamping force control according to the present embodiment, a predetermined operation amount of the mold clamping device when generating the mold clamping force by the mold clamping device is set, and the mold clamping device is set by the predetermined operation amount. The magnitude of the mold clamping force generated when it is driven is detected, the correspondence between the predetermined amount of operation and the magnitude of the detected mold clamping force is stored, and the mold clamping force is adjusted using the correspondence To do.

  Here, the above-mentioned predetermined operation amount is an amount that the mold clamping device drives its components in order to generate a mold clamping force, and is, for example, an amount of movement (advancing amount) of the movable platen 13. The amount of movement (push-in amount) of the movable platen 13 can be obtained by the position sensor 40 shown in FIG. Alternatively, the movement amount of the cross head 24 of the toggle mechanism 20 or the movement amount of the toggle support 15 may be used as the predetermined operation amount. The movement amount of the cross head 24 can be obtained by the mold opening / closing 1 sensor 27 shown in FIG. Further, the movement amount of the toggle support 15 can be obtained by the mold clamping position sensor 32 shown in FIG. Therefore, in order to perform the mold clamping force control according to the present embodiment, the mold clamping device does not need to include all of the position sensor 40, the mold opening / closing position sensor 27, and the mold clamping position sensor 32. It only has to be provided.

  Moreover, the magnitude | size of the above-mentioned mold clamping force can be detected with the mold clamping force sensor 18 shown in FIG. Alternatively, instead of the mold clamping force sensor 18 for measuring the strain of the tie bar 16, for example, a load cell such as a load cell is provided at the pressure receiving portion of the toggle mechanism 20 or the pressure receiving portion of the movable platen 13 or the fixed platen 12 to increase the clamping force. You may detect and measure.

  Further, the correspondence relationship between the magnitude of the predetermined operation amount described above and the magnitude of the detected mold clamping force is the relationship between the driving amount and the mold clamping force as shown in FIGS. 2 and 4, and the rigidity of the mold. It corresponds to a characteristic. Data representing the obtained correspondence relationship is stored in the storage unit of the control device 19 shown in FIG. 1, the storage unit in the control unit of the injection molding machine, or the like, and is read from the storage unit when the mold clamping force is adjusted.

1 is a side view of a mold clamping device to which a mold clamping force control method according to the present invention is applicable. It is a figure which shows the relationship between the amount of driving in and the case where it does not perform auto-tuning, and a mold clamping force. It is the figure which modeled the mold clamping force control system by one Embodiment of this invention. FIG. 5 is a diagram showing a change in a detected value of a mold clamping force when auto tuning is performed and when auto tuning is not performed. It is a figure which shows the change of the mold clamping force at the time of performing mold clamping force adjustment in the preparation stage of shaping | molding.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Mold clamping apparatus 11 Mold apparatus 12 Fixed platen 13 Movable platen 15 Toggle support 16 Tie bar 18 Clamping force sensor 19 Control apparatus 20 Toggle mechanism 26 Clamping motor 27 Mold opening / closing position sensor 31 Mold thickness motor 32 Mold clamping position sensor 40 Position Sensor 42 Scale 50 Node 52 Correction unit 54 Clamping mechanism

Claims (4)

A mold clamping force control method of a mold clamping device for obtaining a mold clamping force by pressing a movable mold attached to a movable part against a fixed mold attached to a fixed part by moving the movable part,
A predetermined operation amount of the mold clamping device when generating a mold clamping force by the mold clamping device;
Detecting the magnitude of mold clamping force generated when the mold clamping device is driven by the predetermined operation amount;
Storing the correspondence between the magnitude of the predetermined operation amount and the magnitude of the detected clamping force;
Use this correspondence to adjust the clamping force ,
A mold clamping force control method using a moving amount of a movable platen as the operation amount . A mold clamping force control method of a mold clamping device for obtaining a mold clamping force by pressing a movable mold attached to a movable part against a fixed mold attached to a fixed part by moving the movable part,
A predetermined operation amount of the mold clamping device when generating a mold clamping force by the mold clamping device;
Detecting the magnitude of mold clamping force generated when the mold clamping device is driven by the predetermined operation amount;
Storing the correspondence between the magnitude of the predetermined operation amount and the magnitude of the detected clamping force;
Use this correspondence to adjust the clamping force,
The mold clamping device is a device that moves a movable platen using a toggle mechanism,
One of the movement amount of the cross head of the toggle mechanism and the movement amount of the toggle support is used as the operation amount . The mold clamping force control method according to claim 1 or 2 ,
A mold clamping force control method, wherein the correspondence is acquired in a molding preparation stage when molding is performed using the movable mold and the fixed mold. A mold clamping force control method according to any one of claims 1 to 3,
Acquiring the correspondence during the mold clamping process while performing the molding process using the movable mold and the fixed mold,
Mold feature and to that mold clamping force control method to feedback control of the mold clamping force based clamping process the detected mold clamping force in the on and the correspondence relation

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