JP2007245412A - Mold thickness measuring method of injection molding machine and mold thickness measuring instrument - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To measure the thickness of a mold by utilizing a molded product ejector. <P>SOLUTION: The mold 21a attached to a fixed platen 12 and the movable mold 21b attached to a movable platen 14 are set to a closed state. The movable part 31 of the molded product ejector 30 is moved to detect the movable platen 14 by a sensor 34 and the position Ps of the movable part 31 at this time is calculated. The thickness MH of the mold is calculated from the offset value P0 of the origin position of the coordinates system of the molded product ejector 30 and the origin position of the coordinates system of an injection molding machine and the calculated position Ps as MH=Ps-Po. Since the thickness of the mold can be measured by utilizing the mold ejector, it can be measured inexpensively, simply an accurately. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method and an apparatus for measuring the thickness of a mold used in an injection molding machine.

  In an injection molding machine using a toggle type mold clamping device, a toggle link mechanism of a toggle type mold clamping device is arranged between a rear platen and a movable platen, and a set mold clamping force is generated with the toggle link extended. It is. Therefore, mold thickness adjustment is performed to adjust the position of the toggle type mold clamping device, that is, the position of the rear platen, according to the thickness of the mold and further according to the set mold clamping force.

  For this mold thickness adjustment, a method of measuring the thickness of the mold in advance and adjusting the position of the toggle type mold clamping device, that is, the position of the rear platen according to the measured thickness of the mold is adopted. ing. For example, when changing the mold, measure the thickness of the new mold, move the rear platen by the deviation from the thickness of the old mold, and then adjust the clamping force Is known (see Patent Documents 1, 2, and 3).

  In addition, as a means for measuring the mold thickness, a position detector for detecting the position of the movable platen is attached to the base of the injection molding machine, and the thickness of the mold can be detected by detecting the position of the movable platen. (See Patent Document 4), an encoder is known in which an encoder is attached to a fixed platen and the distance between the fixed platen and the movable platen is measured with this encoder in a state where the mold is closed (see Patent Document 5).

  Further, the injection molding machine is provided with a molded product take-out device such as a robot for taking out the molded product from the mold. This molded product take-out device is equipped with an actuator for capturing and taking out the molded product by holding or adsorbing the molded product at the tip of the movable part, and moves into the mold after the mold is opened. The molded product is taken out by gripping the predetermined position of the sheet. For this purpose, detection means for detecting the position of the movable part is provided (see Patent Document 6).

JP-A 63-17021 JP-A-2-241653 JP-A-2-307723 JP-A-62-255110 JP-A-1-58521 JP-A-61-123456

As described above, the mold thickness adjustment is generally performed by inputting the thickness of the mold, and the thickness of the mold needs to be measured in advance. As a method of measuring the thickness of the mold, as described in Patent Documents 4 and 5, the measuring instrument is provided in the injection molding machine, and the measuring instrument is newly added to the injection molding machine. There is a problem that it must be disposed and is expensive accordingly. Also, it is possible to measure by using a ruler or caliper, or by checking the CAD drawing of the mold, but if there is a measurement error or confirmation error, the machine or mold will be There was a problem in terms of reliability because of the possibility of damage.
Therefore, an object of the present invention is to provide a method and an apparatus for measuring a mold thickness using a molded product taking-out apparatus.

The invention according to claims 1 to 4 of the present application is a method for measuring a mold thickness in an injection molding machine provided with a molded product taking-out device, and the invention according to claim 1 is provided in a movable part of the molded product taking-out device. A sensor for detecting a movable platen is provided, the movable part of the molded product takeout apparatus is moved, the movable platen is detected by the sensor, and the position of the movable part in the molded product takeout apparatus when the movable platen is detected; The mold thickness is obtained based on the mounting position of the take-out device with respect to the injection molding machine. The invention according to claim 2 measures the movable platen position when the mold is closed, and the invention according to claim 3 measures the movable platen position when the mold is open. The mold thickness is obtained based on the position of the movable part, the position where the take-out device is attached to the injection molding machine, and the amount of mold opening.
Further, the invention according to claim 4 is configured such that the sensor is a sensor that detects the movable platen in contact or non-contact, or the drive current of the motor that drives the movable part exceeds a reference value. Alternatively, a disturbance estimation observer is incorporated into the motor that drives the movable part, and when the load estimated by the disturbance estimation observer exceeds a predetermined value, it is detected that the movable part is in contact with the movable platen, thereby detecting the sensor. It was supposed to constitute.

  According to a fifth aspect of the present invention, there is provided a mold thickness measuring device for an injection molding machine provided with a molded product removing device, wherein a sensor for detecting a movable platen is provided at a movable portion of the molded product removing device. The molded product take-out apparatus is provided with means for determining the position of the movable part in the molded product take-out apparatus by detecting the movable platen by the sensor, and comprises a communication means between the molded product take-out apparatus and the injection molding machine, The molding product taking-out apparatus or the injection molding machine includes means for calculating a mold thickness based on the obtained position of the movable part and the mounting position of the taking-out apparatus with respect to the injection molding machine.

  Since the present invention can measure the thickness of a mold by using a molded product taking-out apparatus, it does not require a special expensive means for measuring the mold thickness, and measures the thickness of the mold easily and accurately. be able to.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a principal block diagram of a mold clamping device, a molded product take-out device, and a control device thereof for an injection molding machine that implements an embodiment of the present invention.
In a toggle type mold clamping device 10 of an injection molding machine, a rear platen 13 is connected by a fixed platen 12 fixed to a base frame 11 of the injection molding machine and a plurality of tie bars 15. A movable platen 14 is disposed between the fixed platen 12 and the rear platen 13, and a toggle link mechanism 16 of the toggle type mold clamping device 10 is disposed between the rear platen 13 and the movable platen 14. The movable platen 14 moves to the left and right in FIG. 1 along a linear movement guide (not shown) provided on the base frame 11 along the tie bar 15, and the fixed side mold 21 a attached to the fixed platen 12 and the movable platen 14. The mold 21 composed of the movable mold 21b attached to the mold is closed, clamped and opened.

  The rear platen 13 is provided with a mold opening / closing servomotor 17 that is a drive source of the toggle type mold clamping device. The mold opening / closing servomotor 17 is configured to connect a crosshead of the toggle link mechanism 16 via a transmission mechanism 19. Driven, the toggle link mechanism 16 is driven, the toggle link is expanded and contracted, and the movable platen 14 is moved. Reference numeral 17a denotes a position / speed detector that detects the position and speed of the movable platen 14 by detecting the position and speed of the mold opening / closing servomotor 17.

  The rear platen 13 is provided with a motor 18 for moving the mold back and forth. The motor 18 for moving the mold back and forth moves the rear platen 13 along the tie bar 15 via the transmission mechanism 20 to move the mold. The thickness and mold clamping force are adjusted.

  In addition, a molded product taking-out device 30 is arranged in the vicinity of the injection molding machine. The molded product take-out device 30 is for taking out the molded product from the mold, and has a capturing means for capturing the molded product by gripping or adsorbing the molded product at the tip of the movable portion 31, and this capturing means. A linear movement axis and a rotation axis for moving the tip of the capturing means are provided so that the molded product can be positioned at the capture position (gripping position or suction position) in the mold that has been opened. For example, when the moving direction of the movable mold 21b of the mold 21 (moving direction of the movable platen 14) is the X-axis direction, the Y-axis direction orthogonal to the X-axis direction and the Z-axis orthogonal to the X and Y-axis directions Mold 21 opened by moving the interpolation means at the tip of the movable part, such as one that can move in three axial directions, or one that can move linearly in at least the X-axis direction and rotate around an axis parallel to the X-axis. The molded product can be taken out from the container and transported to the outside. The molded product take-out device usually has drive means for moving the movable part at least in the X-axis direction.

  The molded product take-out device 30 shown in FIG. 1 is also a molded product take-out device similar to the conventional one, but shows only the portion related to the present invention, and transmits the rotational motion consisting of screws and nuts into linear motion. Only the servo motor 32 that drives the movable portion 31 in the X-axis direction (the moving direction of the movable platen 14) via the mechanism 33 is shown. In connection with the present invention, a sensor 34 is attached to the tip of the movable portion 31. The sensor 34 may be a limit switch or a photoelectric non-contact sensor. The sensor 34 and the servo motor 32 are connected to a control device 35 of the molded product removing device. The servo motor 32 is provided with a position / speed detector 32a for detecting the position of the movable portion 31, that is, the position of the sensor 34 in the X-axis direction by detecting the rotational position of the servo motor 32. The position and speed detected by the position / speed detector 32a are fed back to the control device of the molded product take-out apparatus. When the control device 35 of the molded product take-out apparatus drives the servo motor 32 to move the movable portion 31 in the X-axis direction, the sensor 34 comes into contact with the movable platen 14, and when the contact signal is received from the sensor 34, The position of the sensor at the contact position, that is, the position in the coordinate system of the molded product take-out device is obtained.

  The injection molding machine control device 100 includes a CNC CPU 102 which is a numerical control microprocessor, a PMC CPU 101 which is a programmable machine controller microprocessor, and a servo CPU 110 which is a servo control microprocessor. By selecting mutual input / output via 109, information can be transmitted between the microprocessors. In addition, a communication interface 111, a display / manual input unit 104, and a molding data storage RAM 103 are connected to the bus 109.

  The PMC CPU 101 is connected to a ROM 105 storing a sequence program for controlling the sequence operation of the injection molding machine and a RAM 106 used for temporary storage of calculation data. The mold clamping device forward / reverse motor 18 is controlled by the PMC CPU 101.

  Connected to the CNC CPU 102 are a ROM 107 storing an automatic operation program and the like for overall control of the injection molding machine, and a RAM 108 used for temporary storage of calculation data.

  Further, the servo CPU 110 is connected to a ROM 113 storing a control program dedicated to servo control that performs processing of a position loop, a speed loop, and a current loop, and a RAM 114 used for temporary storage of data. Further, the servo CPU 110 is connected to a servo amplifier that drives a servo motor for each axis for mold clamping, injection, screw rotation, etc. based on a command from the CPU 110, and is attached to the servo motor for each axis. The output from the position / speed detector is fed back to the servo CPU 110. FIG. 1 shows only the servo amplifier 112 that drives the mold opening / closing servomotor 17 related to the present invention.

The display / manual input unit 104 can perform various data input operations, etc., with a display composed of a CRT or a liquid crystal, and is provided with numeric data input numeric keys and various function keys.
A molding data storage RAM 103 composed of a non-volatile memory is a molding data storage memory for storing molding conditions, various set values, parameters, and the like relating to injection molding operations.
A communication means 115 such as Ethernet (registered trademark) or RS-232C is connected to the communication interface 111, and is connected to the control device 35 of the molded product removing device.

  With the above configuration, the PMC CPU 101 controls the sequence operation of the entire injection molding machine, and the CNC CPU 102 controls the servo motor for each axis based on the molding program stored in the operation program of the ROM 107 and the data storage RAM 108. The servo CPU 110 performs position loop control as in the prior art based on the movement command distributed to each axis and the position and speed feedback signals detected by the position / speed detector. Servo control such as speed loop control and current loop control is performed, and so-called digital servo processing is executed. The injection molding machine control by the injection molding machine control device 100 is the same as the conventional one.

  In this embodiment, the control device 100 of the injection molding machine and the control device 35 of the molded product take-out device are connected by the communication means 115, and the mold is controlled by the control device 100 of the injection molding machine and the control device 35 of the molded product take-out device. The measuring apparatus that automatically performs the thickness measurement of the above is configured, and the measuring method is characterized.

  Since the molded product take-out device 30 takes out the molded product from the mold 21 attached to the mold clamping device 10 of the injection molding machine, it has to teach the capture position of the molded product. When the mold opens, it needs to move to its taught capture position to capture and remove the molded product. Therefore, the relationship between the coordinate system provided in the molded product take-out apparatus and the coordinate system of the injection molding machine is set in advance. That is, each axial distance from the origin of the coordinate system of the injection molding machine to the origin of the coordinate system of the molded product take-out apparatus is set as an origin offset (offset vector). Therefore, the position in the coordinate system of the injection molding machine corresponding to the position in the coordinate system of the molded product take-out apparatus can be obtained.

  In the present invention, the thickness of the mold is measured using the molded product take-out device 30. A sensor 34 is attached to the tip of the movable portion of the molded product take-out device, and the movable portion 31 is moved in the X-axis direction. The thickness of the mold 21 is measured by detecting the movable platen 14 and detecting the movable platen 14 (contact detection if the sensor is a limit switch).

FIG. 2 is an explanatory diagram of the first embodiment of this mold thickness measuring method.
The movable platen 14 is moved to bring the fixed mold 21a attached to the fixed platen 12 and the movable mold 21b attached to the movable platen 14 into contact with each other so that the mold is closed. This is driven by limiting the output of the mold opening / closing servomotor 17 to a low torque, and the mold 21 is brought into contact with the low torque to close the mold.

  Then, the control device 35 of the molded product take-out device drives the servo motor 32 until the movable platen detection signal is sent from the sensor 34 by moving the movable portion 31 by driving the servo motor 32. When the detection signal is sent from the sensor 34, the drive of the servo motor 32 is stopped, and the position Ps of the sensor 34 at that time is determined by the position feedback signal from the position / speed detector 32a provided in the servo motor 32. The position is obtained from the current position register. The thickness of the mold 21 is calculated from the obtained position Ps.

In FIG. 2, it is assumed that the mold thickness is MH, the origin of the coordinate system of the injection molding machine is set to the mold mounting surface of the fixed platen 12, and the origin of the coordinate system of the injection molding machine and the molded product. If the value in the X-axis direction of the origin offset distance from the origin of the coordinate system of the take-out device is P0, the mold thickness MH is obtained by the following first formula.
MH = Ps−P0 (1)
Note that the origin offset distance between the origin of the coordinate system of the injection molding machine and the origin of the coordinate system of the molded product take-out apparatus is naturally determined by the molded product mounting position with respect to the injection molding machine, and is set in advance.

FIG. 3 is an explanatory diagram of a second embodiment of the mold thickness measuring method.
In this embodiment, the mold thickness is measured with the mold opened. This embodiment is used when it is difficult to close the mold and measure its thickness for some reason.
After the mold opening / closing servo motor 17 is driven and the mold 21 is closed, the mold opening / closing servo motor 17 is reversely rotated to move a predetermined amount. The mold opening amount Pd between the fixed mold 21a and the movable mold 21b is obtained from the reverse rotation amount of the mold opening / closing servomotor 17 at this time. Thereafter, in the same manner as in the first embodiment, the servo motor 32 of the molded product removing device is driven until the movable platen is detected by the sensor 34, and the sensor 34 when the detection signal is sent from the sensor 34 is driven. The position Ps is obtained. From the position Ps, the origin offset distance between the origin of the coordinate system of the injection molding machine and the origin of the coordinate system of the molded product take-out device, the value in the X-axis direction is P0 and the mold opening amount Pd. Is obtained by the following second equation.

MH = Ps−P0−Pd (2)
FIG. 4 and FIG. 5 are flowcharts showing an algorithm of processing executed by the injection molding machine and the molded product taking-out apparatus when performing the mold thickness measurement in the first embodiment described above.
FIG. 4 is a flowchart of processing executed by the CNC CPU 102 of the control device 100 of the injection molding machine, and FIG. 5 is a flowchart executed by the processor of the control device 35 of the molded product removing device.

  When a mold thickness measurement command is input from the display / manual input unit 104, the CNC CPU 102 in the control device 100 of the injection molding machine issues a forward (mold closing direction) movement command to the mold opening / closing servomotor 17. The servo CPU 110 limits the output torque and drives the mold opening / closing servomotor 17 in the mold closing direction (step a1). Then, it is determined whether there is a position feedback signal from the position / speed detector 17a attached to the mold opening / closing servomotor 17. Since the mold opening / closing servo motor 17 is driven with its output torque limited, the movable platen and the movable side mold 21b are moved in the mold closing direction with a low torque, and the movable side mold 21b is moved. When it comes into contact with the fixed mold 21a, its movement is blocked. Further, since the rotation of the mold opening / closing servomotor 17 is also stopped, the position feedback signal from the position / speed detector 17a is not changed.

  When it is detected that the position feedback signal has disappeared (step a2), the driving of the mold opening / closing servomotor 17 is stopped and held at the position (step a3). Then, a mold thickness measurement command is transmitted to the control device 35 of the molded product removal device 30 via the communication interface 111 and the communication means 115 (step a4), and the measurement result is sent from the control device 35 of the molded product removal device 30. Wait for it to come (step a5).

  The processor of the control device 35 of the molded product take-out apparatus monitors whether or not a mold thickness measurement command is sent from the injection molding machine (step b1), and when this measurement command is sent, has a sensor 34 at the tip. The servo motor 32 that moves the movable part 31 in the mold opening / closing direction (X-axis direction) starts to be driven toward the movable platen 14 (step b2), and waits for a detection signal of the movable platen 14 from the sensor 34 (step b3). .

  When the movable portion 31 moves in the direction of the movable platen, the sensor 34 comes into contact with the movable platen 14 and the detection signal is input to the control device 35 of the molded product removal device as shown in FIG. The servo motor 32 is stopped (step b4), the position Ps stored in the current position register calculated based on the position feedback fed back from the position / velocity detector 32a is read, and communication means is communicated to the control device 100 of the injection molding machine. 115 (step b5).

  On the other hand, when the control device 100 of the injection molding machine receives the measurement position Ps, the offset value of the origin in the coordinate system of the molded product take-out apparatus with respect to the origin of the coordinate system of the injection molding machine is preset with the position Ps. A mold thickness MH is determined based on P0 (step a6). In this embodiment, as shown in FIG. 2, it is assumed that the origin of the coordinate system of the injection molding machine is set on the mold mounting surface of the fixed platen, and the mold thickness MH is obtained by the above-described first equation. It will be. The mold thickness MH thus obtained is stored in the molding data storage RAM 103 and displayed on the display of the display / manual input unit 104 to indicate that the mold thickness measurement has been completed (step a7).

  The processing of the second embodiment shown in FIG. 3 is the same as the processing of the second embodiment except that the processing of step a3 and step a6 is changed. That is, in step a3, after the mold closing is stopped, the mold opening / closing servomotor 17 is moved by a predetermined amount, and the process shifts to a process for obtaining the movement amount Pd of the movable platen 14 at that time. Further, the processing in step a6 is different only in that the mold thickness MH is obtained by the above-described calculation of the second equation. The other processes are the same as those in FIGS.

In each of the above-described embodiments, the process for obtaining the mold thickness MH is performed by the control device 100 of the injection molding machine. However, the process for obtaining the mold thickness MH may be performed on the molded product take-out apparatus side.
In this case, the processing of steps a6 and a7 is performed by the processor of the control device 35 of the molded product removal device after step b6, and the processing after step a5 is not necessary on the injection molding machine side.

  In each of the above-described embodiments, a sensor such as a limit switch is provided at the tip of the movable part 31 of the molded product taking-out device to detect the movable platen position. The position of the movable platen may be detected by detecting disturbance torque using a position detection sensor or a disturbance estimation observer. That is, when the servo motor 32 is driven to move the movable portion 31 forward and the movable portion 31 comes into contact with the movable platen 14 and cannot move forward, the servo motor 32 increases its output torque in an attempt to advance the movable portion 31. Drive current increases. Therefore, when the drive current becomes equal to or greater than a predetermined reference value, it is detected that the movable portion 31 is in contact with the movable platen 14, and the position Ps of the movable portion at this time is obtained, thereby obtaining the thickness of the mold. Can be measured.

  Further, a disturbance estimation observer is incorporated in the control system of the servo motor 32 to detect a load applied to the servo motor 32. As described above, when the movable portion 31 comes into contact with the movable platen 14, the load on the servo motor increases. Therefore, the disturbance estimation observer detects this increase in load, and the movable portion 31 comes into contact with the movable platen 14. And the thickness of the mold can be measured by obtaining the position Ps of the movable part at this time.

As described above, the sensor for detecting the movable platen of the movable portion 31 described above may be configured by the determination processing whether the drive current of the servo motor has become the reference value or more, or by the disturbance estimation observer.
In the above-described embodiment, an example of a toggle type mold clamping device is shown, but the mold thickness can be measured by the same method even with other mold clamping devices such as a crank type and a direct pressure type. .

It is a principal part block diagram of the mold clamping apparatus of the injection molding machine which implements one Embodiment of this invention, a molded article taking-out apparatus, and its control apparatus. It is explanatory drawing of 1st Embodiment of the mold thickness measuring method of this invention. It is explanatory drawing of 2nd Embodiment of the mold thickness measuring method of this invention. It is a flowchart which shows the algorithm of the process of the injection molding machine in 1st Embodiment. It is a flowchart which shows the algorithm of the process of the molded article extraction apparatus in 1st Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Mold clamping device 11 Base frame 12 Fixed platen 13 Rear platen 14 Movable platen 15 Tie bar 16 Toggle link mechanism 17 Mold opening / closing servo motor 17a Position / speed detector 18 Mold clamping device forward / backward moving motor 21 Mold 30 Mold take-out device 31 Movable part 32 Servo motor 32a Position / velocity detector 34 Sensor 35 Control device for molded product take-out device 100 Control device for injection molding machine 115 Communication means

Claims (5)

  A mold thickness measuring method in an injection molding machine equipped with a molded product take-out device, wherein a sensor for detecting a movable platen is provided in the movable part of the molded product take-out device, and the movable part of the molded product take-out device is moved. Then, the movable platen is detected by the sensor, and the mold thickness is obtained on the basis of the position of the movable portion in the molded product take-out apparatus when the movable platen is detected and the position of the take-out apparatus attached to the injection molding machine. A method for measuring a mold thickness of an injection molding machine.   2. The mold thickness measuring method for an injection molding machine according to claim 1, wherein the movable platen position is measured when the mold is closed.   The measurement of the movable platen position is performed when the mold is opened, and the mold thickness is obtained based on the position of the movable part, the mounting position of the take-out device with respect to the injection molding machine, and the mold opening amount. The method of measuring a mold thickness of an injection molding machine according to claim 1, wherein the mold thickness is measured.   The sensor is configured by a sensor that detects the movable platen in contact or non-contact, or when a drive current of a motor that drives the movable part exceeds a reference value, or a motor that drives the movable part. A disturbance estimation observer is incorporated, and when the load estimated by the disturbance estimation observer exceeds a predetermined value, the sensor is configured by detecting that the movable part is in contact with the movable platen. 4. The mold thickness measuring method for an injection molding machine according to any one of 1 to 3. A mold thickness measuring device in an injection molding machine equipped with a molded product removing device,
A sensor for detecting a movable platen is provided in the movable part of the molded product take-out device, and means for obtaining the position of the movable part in the molded product take-out device by detecting the movable platen in the molded product take-out device. Provided with a communication means between the molded product take-out device and the injection molding machine, and a means for calculating a mold thickness based on the obtained position of the movable part and the attachment position of the take-out device with respect to the injection molding machine An apparatus for measuring a thickness of a mold of an injection molding machine, which is provided in a molded product take-out apparatus or an injection molding machine.

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