JP2012228822A - Method and device for controlling mold opening/closing speed of injection molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a device for controlling a mold opening/closing speed of an injection molding machine for controlling a cross-head of a toggle mechanism to prevent rapid change of a speed of a movable platen in the toggle type injection molding machine.SOLUTION: In the method for controlling the mold opening/closing speed of the injection molding machine, in the injection molding machine having a toggle mold clamping mechanism, a cross-head speed is set corresponding to the position of the cross-head, and the speed of the movable platen with respect to each position of the cross-head is determined based on the cross-head speed and a speed amplification rate of a toggle link. A section (section B) of the cross-head position where the determined movable platen speed exceeds a preset movable platen speed is determined. The cross-head speed at which the movable platen speed becomes the preset movable platen speed in the determined section (section B) is determined with respect to each cross-head position, on the basis of the speed amplification rate and the preset movable platen speed, so as to perform a mold opening/closing operation of the movable platen.

Description

  The present invention relates to a method and apparatus for controlling the mold opening / closing speed of an injection molding machine.

  In the toggle type mold clamping mechanism, the movable platen is opened and closed by expanding and contracting the toggle by moving the cross head back and forth. Since the speed of the movable platen is amplified by the toggle mechanism, the movable platen accelerates even when the crosshead is operated at a constant speed, and further switches to deceleration at a predetermined position (see, for example, Patent Document 1). At such a switching position from acceleration to deceleration, a mechanical shock occurs, causing vibration and noise.

  The technique disclosed in Patent Document 1 controls the deceleration at the time of stop according to the position of the crosshead, thereby suppressing the impact due to the characteristics of the movable platen, but the crosshead operates at a constant speed. No countermeasures are disclosed for impact caused by acceleration and deceleration of the movable platen during operation.

  On the other hand, the technique disclosed in Patent Document 2 efficiently accelerates the acceleration when accelerating from the stop position in consideration of the characteristics of the movable platen, but the technique disclosed in Patent Document 1 Similarly, no countermeasure is disclosed for the impact caused by acceleration and deceleration of the movable platen when the crosshead is operating at a constant speed.

  Furthermore, the technique disclosed in Patent Document 3 discloses that the position and speed of the movable platen are set, and the movement of the crosshead is controlled so as to achieve the set position and speed. The technique disclosed in this document controls the speed of the movable platen so that it always becomes a set value, thereby preventing a sudden change from acceleration to deceleration of the movable platen. However, with this technology, since the movable platen speed is always controlled to be a set value, depending on the setting, the crosshead speed is limited at a position where no impact is generated, and the original mechanical performance cannot be sufficiently exhibited. is there.

JP 2004-155063 A JP 2010-1111021 A JP 63-112136 A

  In a mold clamping mechanism having a toggle mechanism, the movable platen is accelerated and decelerated by the toggle speed amplifying mechanism even when the crosshead for bending and extending the toggle mechanism for moving the movable platen back and forth is operated at a constant speed. When the switching from acceleration to deceleration is suddenly performed, an impact is generated. For this reason, conventionally, the movement speed of the cross head has been reduced uniformly, thereby reducing the speed of the movable platen to suppress the acceleration of the movable platen and to suppress the impact. However, evenly reducing the speed increases the mold opening and closing time, and further the time of the entire molding cycle, which causes a problem of reducing productivity.

  Accordingly, an object of the present invention is to provide an injection molding machine that controls the crosshead of the toggle mechanism so that the speed of the movable platen does not suddenly change from acceleration to deceleration in an injection molding machine that opens and closes the movable platen by a toggle mechanism. To provide a method and apparatus for controlling the mold opening and closing speed.

The invention according to claim 1 of the present application is directed to an injection molding machine having a mold clamping mechanism for operating a movable platen by expanding and contracting a toggle link by moving the crosshead back and forth, so that the crosshead corresponds to the position of the crosshead. Set the speed, find the speed of the movable platen for each crosshead position based on the crosshead speed and the speed gain of the toggle link,
The section of the crosshead position where the obtained movable platen speed exceeds the preset movable platen speed is obtained, and the crosshead speed at which the movable platen speed becomes the preset movable platen speed in the obtained section is determined as the speed. Based on the amplification factor and the set movable platen speed, it is obtained for each crosshead position, and the mold opening / closing operation of the movable platen is performed according to the obtained crosshead speed for each crosshead position in the obtained section. The mold opening / closing speed control method of the injection molding machine is characterized in that the mold opening / closing operation of the movable platen is performed according to the set crosshead speed at other crosshead positions.

  According to a second aspect of the present invention, in the injection molding machine having a mold clamping mechanism for operating the movable platen by extending and retracting the toggle link by moving the crosshead back and forth, the speed of the crosshead corresponding to the position of the crosshead. And calculating the total momentum of the movable platen and the mold for each crosshead position based on the crosshead speed, the speed gain of the toggle link, the movable platen mass, and the mold mass, and the obtained movable platen And a section where the total momentum of the mold exceeds a preset total momentum of the movable platen and the mold, and in the determined section, the total momentum of the movable platen and the mold is the set movable platen and mold The crosshead speed, which is the total momentum of the above, the speed gain, the preset total momentum, the mass of the movable platen and the mold The movable platen is opened and closed according to the crosshead speed for each crosshead position in the determined section, and the set crosshead speed is set for other crosshead positions. The mold opening / closing operation of the movable platen is performed in accordance with the control method of the mold opening / closing speed of the injection molding machine.

  According to a third aspect of the present invention, there is provided an injection molding machine having a mold clamping mechanism for operating a movable platen by expanding and contracting a toggle link by moving the crosshead back and forth, and corresponding to the position of the crosshead. A setting unit for setting a speed, a movable platen speed calculating unit for calculating the speed of the movable platen for each crosshead position based on the crosshead speed and the speed amplification factor of the toggle link, and the calculated movable platen speed A section calculation unit for obtaining a section of a crosshead position exceeding a set movable platen speed, and a crosshead speed at which the movable platen speed becomes the preset movable platen speed in the determined section, A crosshead speed calculation unit for each crosshead position based on the set movable platen speed; The movable platen is opened / closed according to the crosshead speed for each crosshead position in the determined section, and the movable platen is moved according to the set crosshead speed at other crosshead positions. A mold opening / closing speed control apparatus of an injection molding machine characterized by performing a mold opening / closing operation.

  According to a fourth aspect of the present invention, there is provided an injection molding machine having a mold clamping mechanism for operating a movable platen by expanding and contracting a toggle link by moving the crosshead back and forth, and the speed of the crosshead corresponding to the position of the crosshead. And a total momentum calculation for obtaining a total momentum of the movable platen and the mold for each crosshead position based on the crosshead speed, the toggle link speed amplification factor, the movable platen mass, and the mold mass. A section calculating section for obtaining a section in which the calculated total momentum of the movable platen and the mold exceeds a preset total momentum of the movable platen and the mold, and the movable platen and the mold in the determined section. The crosshead speed at which the total momentum is the total momentum of the set movable platen and mold is set as the speed gain and the preset value. A crosshead speed calculation unit that obtains each crosshead position based on the total momentum and the mass of the movable platen and the mold, and in the obtained section, the crosshead speed for each obtained crosshead position Therefore, the mold opening / closing operation of the movable platen is performed, and the mold opening / closing operation of the movable platen is performed at other crosshead positions according to the set crosshead speed. Device.

  According to the present invention, in an injection molding machine that opens and closes a movable platen by a toggle mechanism, the mold opening and closing speed of the injection molding machine that controls the crosshead of the toggle mechanism so that the speed of the movable platen does not suddenly change from acceleration to deceleration. Control method and apparatus can be provided.

It is a block diagram of the injection molding machine to which this invention is applied. It is a figure explaining the example of speed setting of the mold closing process which a user sets. It is a figure explaining the crosshead speed for every predetermined crosshead position. It is a graph explaining the relationship between the position of a crosshead, a speed gain, a crosshead speed, and a movable platen speed. It is a figure explaining the crosshead speed by this invention. It is a figure explaining the example of speed restriction.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram of an injection molding machine that controls the mold opening and closing speed according to the present invention. The injection molding machine M includes a mold clamping part Mc and an injection part Mi on a machine base (not shown). The injection part Mi heats and melts a resin material (pellet), and injects the molten resin into the cavity of the mold 40. The mold clamping part Mc mainly opens and closes the mold 40 (movable side mold 40a, fixed side mold 40b).

  First, the injection part Mi will be described. A nozzle 2 is attached to the tip of the injection cylinder 1, and a screw 3 is inserted into the injection cylinder 1. The screw 3 is provided with a resin pressure sensor 5 using a load cell or the like that detects the resin pressure by the pressure applied to the screw 3. The resin pressure sensor output signal is converted into a digital signal by the A / D converter 16 and input to the servo CPU 15.

  The screw 3 is rotated by a screw rotating servo motor M2 via a transmission mechanism 6 composed of a pulley, a belt and the like. Further, the screw 3 is driven by a screw servo motor M1 through a transmission mechanism 7 including a mechanism for converting a rotational motion such as a pulley, a belt, and a ball screw / nut mechanism into a linear motion. Moved in the direction. Reference numeral P1 is a position / speed detector that detects the position and speed of the screw 3 in the axial direction by detecting the position and speed of the servo motor M1 for moving forward and backward, and reference numeral P2 is the position of the servo motor M2. The position / speed detector detects the rotational position and speed around the axis of the screw 3 by detecting the speed. Reference numeral 4 denotes a hopper that supplies resin to the injection cylinder 1.

Next, the mold clamping part Mc will be described. The mold clamping portion Mc includes a movable platen forward / reverse motor M3 that moves the movable platen 30 that is a movable platen forward and backward, a rear platen 31, an ejector forward / reverse motor M4 for ejecting an ejector pin that pushes a molded product out of the mold, a movable platen 30, A tie bar 32, a fixed platen 33, a cross head 34, an ejector mechanism 35, and a toggle mechanism 36 configured by connecting a plurality of toggle links are provided. The rear platen 31 and the fixed platen 33 are connected by a plurality of tie bars 32, and the movable platen 30 is disposed so as to be guided by the tie bars 32. A movable mold 40 a is attached to the movable platen 30, and a fixed mold 40 b is attached to the fixed platen 33. The toggle mechanism 36 can operate the toggle mechanism 36 by advancing and retracting the cross head 34 attached to the ball screw shaft 38 driven by the movable platen forward / reverse motor M3. In this case, when the cross head 34 is moved forward (moved in the right direction in the figure), the movable platen 30 is moved forward to perform mold closing. Then, after the movable mold 40a and the fixed mold 40b come into contact, the crosshead 34 is further advanced until the toggle mechanism 36 is fully extended, thereby generating a mold clamping force.
The rear platen 31 is provided with a mold clamping position adjusting motor M5. A driving gear (not shown) is attached to the rotating shaft of the mold clamping position adjusting M5. The rotational force of the rotational force of the driving gear is transmitted to all gears of tie bar nuts (not shown) by other gears (not shown). That is, when the mold clamping position adjusting motor M5 is driven, the transmission mechanism causes the tie bar nut screwed to the screw portion 37 of the tie bar 32 to be rotated in synchronization. Accordingly, the mold clamping position adjusting motor M5 can be rotated in a predetermined direction by a predetermined number of rotations, and the rear platen 31 can be advanced and retracted by a predetermined distance. The mold clamping position adjusting motor M5 is preferably a servomotor as shown in the figure, and includes a position detector P5 for detecting the rotational position. The detection signal of the rotational position of the mold clamping position adjusting motor M5 detected by the position detector P5 is input to the servo CPU 15.

  The control device 100 of the injection molding machine M includes a CNC CPU 20 that is a microprocessor for numerical control, a PMC CPU 17 that is a microprocessor for a programmable machine controller, and a servo CPU 15 that is a microprocessor for servo control. Thus, by selecting mutual input / output, information can be transmitted between the microprocessors.

  The servo CPU 15 is connected to a ROM 13 that stores a control program dedicated to servo control that performs processing of a position loop, a speed loop, and a current loop, and a RAM 14 that is used for temporary storage of data. The servo CPU 15 is connected via an A / D (analog / digital) converter 16 so as to detect a pressure signal from a resin pressure sensor 5 provided on the injection molding machine main body side. The servo CPU 15 is connected to servo amplifiers 11 and 12 for driving the injection servo motor M1 connected to the injection shaft and the screw rotation servo motor M2 connected to the screw rotation shaft based on a command from the servo CPU 15. The outputs from the position / speed detectors P1, P2 attached to the servo motors M1, M2 are fed back to the servo CPU 15. The rotational positions of the servo motors M1 and M2 are calculated by the servo CPU 15 based on the position feedback signals from the position / speed detectors P1 and P2, and updated and stored in the current position storage registers.

  Servo amplifiers 8 and 9 are connected to a servo motor M3 for driving a mold clamping shaft for clamping the mold and an ejector shaft servo motor M4 for taking out a molded product from the mold, respectively. Outputs from position / speed detectors P3 and P4 attached to the servo motors M3 and M4 are fed back to the servo CPU 15. The rotational positions of the servo motors M3 and M4 are calculated by the servo CPU 15 based on the position feedback signals from the position / speed detectors P3 and P4, and updated and stored in the current position storage registers.

  A ROM 18 storing a sequence program for controlling the sequence operation of the injection molding machine and a RAM 19 used for temporary storage of calculation data are connected to the PMC CPU 17, and an automatic operation program for overall control of the injection molding machine is connected to the CNC CPU 20. A ROM 21 storing various programs such as a control program for realizing mold opening / closing control related to the present invention and a RAM 22 used for temporary storage of calculation data are connected. The molding data storage RAM 23 is a non-volatile memory, and is a memory for storing molding data that stores molding conditions relating to injection molding operations, various set values, parameters, macro variables, and the like. A display device / MDI (manual data input device) 25 is connected to the bus 26 via an interface (I / F) so that a function menu can be selected and various data can be input. Furthermore, a numeric keypad for inputting numeric data and various function keys are provided. The display device may be an LCD (liquid crystal display device), CRT, or other display device.

  With the above-described configuration of the injection molding machine M, the PMC CPU 17 controls the sequence of the entire injection molding machine, and the CNC CPU 20 controls the servo motors of the respective axes based on the molding conditions stored in the operation program of the ROM 21 and the molding data storage RAM 23. The servo CPU 15 distributes the movement command to each axis, and the servo CPU 15 is based on the movement command distributed to each axis and the position and speed feedback signals detected by the position / speed detectors P1, P2, P3, P4 and P5. The digital servo processing is executed to drive and control the servo motors M1, M2, M3, M4, and M5.

  A molding operation using the injection molding machine M will be described. When the movable platen forward / reverse motor M3 is rotated in the forward direction, the ball screw shaft 38 is rotated in the forward direction, the cross head 34 screwed to the ball screw shaft 38 is advanced, and the toggle mechanism 36 is operated. The movable platen 30 is advanced.

  When the movable mold 40a attached to the movable platen 30 comes into contact with the fixed mold 40b (mold closed state), the mold clamping process is started. In the mold clamping process, the movable platen forward / reverse motor M3 is further driven in the forward direction, whereby the toggle mechanism 36 is extended to generate a mold clamping force on the mold 40. The screw servo motor M1 provided in the injection part Mi is driven to move forward in the axial direction of the screw 3, so that the cavity space formed in the mold 40 is filled with the molten resin. When opening the mold, when the movable platen forward / reverse motor M3 is driven in the reverse direction, the ball screw shaft 38 is rotated in the reverse direction. Along with this, the cross head 34 moves backward, the toggle mechanism 36 operates in a bending direction, and the movable platen 30 moves backward in the direction of the rear platen 31. When the mold opening process is completed, the ejector forward / reverse motor M4 for ejecting the ejector pin that pushes out the molded product from the movable mold 40a is operated. Thereby, an ejector pin (not shown) is protruded from the inner surface of the movable mold 40a, and a molded product in the movable mold 40a is protruded from the movable mold 40a.

Next, the mold closing and mold opening operations of the movable platen 30 according to the present invention will be described.
Since the movable platen 30 is driven by the movable platen forward / reverse motor M3 via the toggle mechanism 36, the speed and acceleration of the movable platen forward / backward motor M3 are not proportional to the moving speed of the movable platen 30. Is different. On the other hand, the movable side mold 40a of the mold 40 is fixed to the movable platen 30, and the position, speed, and acceleration of the movable platen 30 are determined in order to perform the mold closing and clamping operation of the mold 40. Need to control.

  Since the movable platen 30 is driven by the movable platen forward / reverse motor M3, the position, speed, and acceleration of the movable platen 30 are controlled by controlling the position, speed, and acceleration of the movable platen forward / backward motor M3. Will be controlled by. However, since the position, speed, and acceleration of the movable platen forward / reverse motor M3 are not proportional to the position, speed, and acceleration of the movable platen 30, even if the movable platen forward / backward motor M3 is rotated at a constant rotational speed, The speed and acceleration of the movable platen 30 vary depending on the position of the movable platen forward / reverse motor M3. On the other hand, since the movable platen forward / reverse motor M3 and the cross head 34 operate in a predetermined proportional relationship, if the position, speed, and acceleration of the cross head 34 are determined, the position, speed, and acceleration of the movable platen forward / backward motor M3 are also determined. It will be. A method for controlling the speed of the motor with an acceleration corresponding to the speed is known.

  Therefore, first, for example, the speed of the crosshead 34 (hereinafter referred to as “crosshead speed”) corresponding to the position of the crosshead 34 (hereinafter referred to as “crosshead position”) in the mold opening / closing operation shown in FIG. Is set using the input means of the display device / MDI (manual data input device) 25 provided in the injection molding machine M to which the present invention shown in FIG. 1 is applied. The set crosshead position and crosshead speed are displayed on the display screen of the display device / MDI (manual data input device) 25 as a graph shown in FIG.

  Then, based on the crosshead speed and the speed amplification factor of the toggle mechanism 36 that performs the mold opening / closing operation, the control device 100 of the injection molding machine M determines the speed of the movable platen corresponding to the crosshead position (hereinafter referred to as “movable platen speed”). Is calculated). When the movable platen speed obtained by the calculation exceeds a preset upper limit speed, the crosshead speed at each crosshead position is based on the speed amplification factor so that the upper limit speed becomes the movable platen speed. And the crosshead is moved at the calculated crosshead speed.

Specifically, the movable platen speed corresponding to the crosshead position Pc is Vm (Pc), the crosshead speed corresponding to the crosshead position Pc is Vc (Pc), and the speed gain G (Pc) of the toggle link mechanism Then, the movable platen speed Vm (Pc) can be expressed by Equation 1.
Vm (Pc) = Vc (Pc) · G (Pc) (Expression 1)
Here, it is well known that Pc is a crosshead position, and the speed gain G (Pc) is a function of the crosshead position Pc (see, for example, JP 2009-251804 A).

  As described above, when the crosshead position Pc and the corresponding crosshead speed Vc (Pc) are set on the display screen of the display device / MDI (manual data input device) 25 of the injection molding machine M (see FIG. 2). Then, the control device 100 reads the crosshead speed Vc (Pc) for each predetermined crosshead position Pc from the setting (see FIG. 3), and determines the relationship between the crosshead position (Pc) and the crosshead speed (Vc (Pc)). It memorize | stores in memory (for example, RAM22). Next, the movable platen speed Vm (Pc) is obtained using Equation 1 for each crosshead position (Pc) stored in the memory.

  Here, when the movable platen speed Vm (Pc) is equal to or higher than the preset upper limit speed VL (that is, Vm (Pc) ≧ VL), Vm (Pc) = VL and solving the equation 1, the crosshead The crosshead speed Vc (Pc) corresponding to the position Pc is obtained and set as a crosshead speed setting value. When Vm (Pc) <VL, Vc (Pc) crosses the crosshead speed Vc (Pc) recorded in the memory. Use the head speed setting value. Here, the upper limit speed VL may be set in advance according to the measurement result of vibration and sound by performing an experiment for each type and size of the machine.

  Since the relationship between the movable platen speed Vm (Pc) and the crosshead position Pc is as shown in FIG. 4, the upper limit speed VL and the movable platen speed Vm (Pc) intersect at two crosshead positions (see FIG. 5). . Therefore, after obtaining the intersection (two points) of Equation 1 and Vm (Pc) = VL in advance, the movable platen speed Vm (Pc) for each predetermined crosshead position Pc between these two points is obtained to obtain the above. Similarly, the crosshead speed Vc (Pc) such that Vm (Pc) = VL may be obtained. The section B is a section of the crosshead position where the position of the movable platen 30 exceeds the preset movable platen speed (speed of the movable platen 30), and the sections A and C are preset with the movable platen speed. It is the section below the movable platen speed.

  The inertial force of the movable platen 30 is determined by the sum of the mass of the movable platen 30 and the mass of the mold (movable side mold 40a) attached to the movable platen 30, and the movable platen 30 is accelerated when the mass is large and the inertial force is large. The impact when decelerating also increases. Since the mold mass differs for each mold, the upper limit speed VL needs to be corrected in consideration of the mold mass. Therefore, the upper limit speed VL at which vibration and sound are appropriate is determined in advance with a reference mold (hereinafter referred to as “reference mold”), and the mass ratio of the reference mold to the actually used mold is determined. The upper limit speed VL may be corrected based on the above.

VLa = VLb * (Mb + Mm) / (Ma + Mm) (Formula 2)
Ma: Mass of actually used mold Mb: Mass of reference mold Mm: Mass of movable platen VLa: Upper limit speed of actual mold VLb: Upper limit speed of reference mold As the mass of the mold to be actually used, the value set by the user on the screen of the injection molding machine may be used, or the acceleration when the movable platen is accelerated by actually performing the mold opening / closing operation is measured by the acceleration sensor. The motor torque for driving the movable platen may be measured at the same time as measured by the above equation (3), and may be obtained by the following equation (3).
Ma + Mm (or Mb + Mm) = Fm / A (Formula 3)
A: Actually measured acceleration of the movable platen Fm: Thrust of the movable platen calculated from the torque of the motor that opens and closes the movable platen

  In any of the above methods, the upper limit speed VL is set by inputting or calculating from the screen of the display device of the injection molding machine. Instead of setting the speed, the upper limit value of the momentum of the movable platen (including the mold) is set. It may be set to control the crosshead speed Vc (Pc) so that the amount of exercise is less than or equal to the upper limit value. In this case, first, the momentum of the movable platen 34 corresponding to the crosshead position Pc is obtained by the equation (4).

Pm (Pc) = (Ma + Mm) * Vm (Pc) (Formula 4)
Pm: Momentum of movable platen (including mold) corresponding to crosshead position Here, the mass of the movable platen + mold (Ma + Mm) is constant regardless of the position of the crosshead. Is equivalent to the momentum of.

  Next, when Pm (Pc) is equal to or greater than a preset upper limit value PL of the momentum (that is, Pm (Pc) ≧ PL), the crosshead position is solved by solving Equation 4 with Pm (Pc) = PL. The movable platen speed Vm (Pc) corresponding to Pc is obtained, and the crosshead speed set value Vc (Pc) is further calculated using the equation (1). When Pm (Pc) <PL, Vc (Pc) is recorded in the memory. The set Vc (Pc) is set as a crosshead speed setting value. Here, the momentum PL can be set on the screen of the injection molding machine so that the user can set an optimum value while judging from the vibration and sound of the machine, or it can be set to a specific value according to the machine type and size. Also good.

  Here, since the relationship between the momentum Pm (Pc) and the crosshead position Pc is also a graph similar to that in FIG. 4, the intersection of the momentum Pm (Pc), the crosshead position Pc, Formula 4, and Pm (Pc) = PL After obtaining (two points) in advance, the momentum Pm (Pc) for each predetermined crosshead position between these two points is obtained, and the crosshead speed Vc such that Pm (Pc) = PL is obtained as described above. (Pc) may be obtained.

  As described above, the upper limit speed of the movable platen and the upper limit value of the momentum are provided to control the crosshead speed, thereby preventing the movable platen speed from rapidly switching from acceleration to deceleration. In the present invention, since the crosshead speed is reduced only in the section where the impact occurs, it is possible to minimize the increase in the cycle time and to suppress the impact.

Pc Crosshead position Vc (Pc) Crosshead speed Vm (Pc) Movable platen speed G (Pc) Speed gain

Claims (4)

In an injection molding machine having a mold clamping mechanism for moving a movable platen by expanding and contracting a toggle link by moving the cross head back and forth,
Set the crosshead speed corresponding to the position of the crosshead,
Determine the speed of the movable platen for each crosshead position based on the crosshead speed and the toggle link speed amplification factor,
Obtain the section of the crosshead position where the obtained movable platen speed exceeds the preset movable platen speed,
A crosshead speed at which the movable platen speed becomes the preset movable platen speed in the obtained section is obtained for each crosshead position based on the speed amplification factor and the set movable platen speed,
In the determined section, the mold movement of the movable platen is performed according to the crosshead speed for each of the determined crosshead positions, and at other crosshead positions, the movable platen is moved according to the set crosshead speed. A method for controlling a mold opening / closing speed of an injection molding machine, wherein a mold opening / closing operation is performed. In an injection molding machine having a mold clamping mechanism for moving a movable platen by expanding and contracting a toggle link by moving the cross head back and forth,
Set the speed of the crosshead corresponding to the position of the crosshead,
Based on the crosshead speed, the speed gain of the toggle link, the movable platen mass and the mold mass, the total momentum of the movable platen and the mold for each crosshead position is obtained,
Obtaining a section in which the total momentum of the movable platen and mold obtained exceeds the preset total momentum of the movable platen and mold,
The crosshead speed at which the total momentum of the movable platen and the mold becomes the total momentum of the set movable platen and the mold in the determined section is the speed amplification factor, the preset total momentum and the movable platen, Calculate for each crosshead position based on the mass of the mold,
The mold opening / closing operation of the movable platen is performed according to the crosshead speed for each crosshead position in the determined section, and the mold opening / closing operation of the movable platen is performed according to the set crosshead speed at other crosshead positions. A method for controlling a mold opening / closing speed of an injection molding machine. An injection molding machine having a mold clamping mechanism for moving a movable platen by extending and retracting a toggle link by moving a cross head back and forth,
A setting unit for setting a crosshead speed corresponding to the position of the crosshead;
A movable platen speed calculation unit for determining the speed of the movable platen for each crosshead position based on the crosshead speed and the speed amplification factor of the toggle link;
A section calculation unit for determining a section of a crosshead position where the determined movable platen speed exceeds a preset movable platen speed;
Crosshead speed calculation for obtaining a crosshead speed at which the movable platen speed becomes the preset movable platen speed in the determined section based on the speed amplification factor and the set movable platen speed. And comprising
In the determined section, the mold opening / closing operation of the movable platen is performed according to the cross head speed for each cross head position, and at the other cross head positions, the mold opening / closing operation of the movable platen is performed according to the set cross head speed. An apparatus for controlling the mold opening and closing speed of an injection molding machine. In an injection molding machine having a mold clamping mechanism for moving a movable platen by expanding and contracting a toggle link by moving the cross head back and forth,
A setting unit for setting the speed of the crosshead corresponding to the position of the crosshead;
A total momentum calculating unit for obtaining a total momentum of the movable platen and the mold for each crosshead position based on the crosshead speed, the speed gain of the toggle link, the movable platen mass, and the mold mass;
An interval calculation unit for obtaining an interval in which the total momentum of the obtained movable platen and the mold exceeds a preset total momentum of the movable platen and the mold;
The crosshead speed at which the total momentum of the movable platen and the mold becomes the total momentum of the set movable platen and the mold in the determined section is the speed amplification factor, the preset total momentum and the movable platen, A crosshead speed calculation unit for each crosshead position based on the mass of the mold,
In the determined section, the mold movement of the movable platen is performed according to the crosshead speed for each of the determined crosshead positions, and at other crosshead positions, the movable platen is moved according to the set crosshead speed. A mold opening / closing speed control device for an injection molding machine, characterized by performing a mold opening / closing operation.

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