JP4850039B2 - Injection molding machine - Google Patents

Description

  The present invention relates to an injection molding machine in which a plurality of molds are mounted on a rotary table at predetermined angular intervals, and the rotary table is intermittently rotated by a predetermined angle.

  Two molds are mounted (attached) on the rotary table at intervals of 180 °, and the rotary table is intermittently rotated in the forward and reverse directions by 180 °, or four on the rotary table. A four-stage type injection molding machine in which dies are mounted at intervals of 90 ° and the rotary table is intermittently rotated in a fixed direction by 90 ° is well known.

  In such an injection molding machine, for example, two fixed molds are provided corresponding to the two movable molds mounted on the rotary table, and each of the pair of the movable mold and the fixed mold is provided. Two injection units are provided to correspond to each other, and each time the rotary table rotates 180 °, the combination of the movable side mold and the fixed side mold is changed alternately, and the two injection units perform injection simultaneously. A horizontal injection molding machine that can easily perform two-color molding without using a complicated mold structure having a moving core or the like is known. Alternatively, for example, a single movable side mold is provided for two fixed side molds mounted on a rotary table, and a single injection unit is provided, and one of the two fixed side molds is provided. By alternately facing the movable mold, injection is performed on the stage where the molds are opposed, and the other stage is configured to place and position the insert article on the fixed mold. There is also known a vertical injection molding machine that can perform insert molding efficiently.

  In addition, for example, four fixed-side molds are mounted on the rotary table at intervals of 90 °, and the rotary table is intermittently rotated by 90 ° in a certain direction, thereby allowing one of the four fixed-side molds to be It is made to stop at the position facing the movable mold that is only provided one by one, placing and positioning the insert article in the mold, injecting and filling the molten resin, and ejecting and ejecting the molded product. In addition, a four-stage type vertical injection molding machine is also known in which each is performed in separate stages to further shorten the molding cycle in insert molding.

  In an injection molding machine using a rotary table as described above, it is necessary to detect the rotational position (rotational angle) of the rotary table, and this rotational position is detected by a servo motor (table rotation) that rotates the rotary table. The encoder attached to the motor for driving) is used. Then, from the state where the rotation table is stopped from rotation, the measurement pulse value is monitored by the encoder output when the rotation table is rotated by a predetermined angle in a predetermined direction, for example, 180 °, and the measurement pulse value is monitored. When the value enters a range indicating a rotation corresponding to about 180 °, it is considered that the rotation has been completed, that is, the rotation table has been rotated to about 180 °, and the measured pulse value represents the damped vibration region before the rotation is stopped. When the predetermined vibration width range set in advance is entered, it is considered that the rotation has ended, and the operation of the next process such as the ejection process is immediately started.

  FIG. 7 is a diagram showing the predetermined vibration width range A and the measurement pulse value 101 described above. In FIG. 7, the transition state of the measurement pulse value 101 along the time axis is schematically shown. In a configuration in which the rotary table is intermittently driven by 180 °, if the rotary table rotates to nearly 180 °, the rotary table is heavy because of the weight of itself and the mounted mold, and has a large inertia. The table oscillates before the rotation completely stops, and as shown in FIG. 7, the measurement pulse value 101 indicates the transition of the damped oscillation. As described above, conventionally, the rotary table rotates to approximately 180 °, and the measurement pulse value 101 is within a predetermined vibration width range A set in advance indicating a damped vibration region before the rotation is stopped. When entering, it is considered that the rotation of the rotary table is completed at the time t2, and the operation of the next process such as the ejection process is started immediately.

  FIG. 8 is a view showing the angle range A ′ of the turntable 102 corresponding to the vibration width range A. In FIG. 8, the angle range A ′ is exaggerated.

  As described above, in the injection molding machine using the conventional rotary table 102, when the measurement pulse value 101 falls within a predetermined predetermined vibration width range A indicating the damped vibration region before the rotation is stopped, At t2, it is considered that the rotation of the turntable 102 is completed, and the operation of the next process such as the ejection process is started immediately. Since it takes time to wait until the damped vibration of the rotary table 102 is completely finished, the next process is started from the point when it can be considered that the rotation of the rotary table 102 is completed. This is to shorten the cycle.

  However, as shown in FIG. 7, the measurement pulse value 101 fluctuates after the time point t2 when the measurement pulse value 101 enters the vibration width range A, and the measurement pulse value 101 remains within the vibration width range after the time point t2. A is protruded, and the rotary table 102 vibrates correspondingly. In particular, when a large-sized mold with a marginal capacity is mounted on the rotary table 102, the rotational inertia is large, and a phenomenon in which the measurement pulse value 101 protrudes greatly from the vibration width range A after time t2 is observed. For this reason, if the ejection operation is performed while the rotary table 102 is not settled, the ejection pin and the insertion hole through which the ejection pin passes will cause galling, which may damage the ejection pin and shorten the life of the ejection pin. In some cases, the eject pin collides with the periphery of the insertion hole and damages the eject pin.

  The present invention has been made in view of the above points, and in an injection molding machine using a rotary table, it is possible to reliably detect a static approximate state that can be almost regarded as the completion of rotation of the rotary table, so that the rotation is completed. Even if the operation of the next process such as the ejection process is started immediately after the determination, the next process can be executed without any trouble.

In order to achieve the above-described object, the present invention provides an injection molding machine in which a plurality of molds are mounted on a rotary table at predetermined angular intervals, and the rotary table is intermittently rotated by a predetermined angle.
An encoder for detecting the amount of rotation of a motor that rotationally drives the rotary table, and a controller that controls the operation of the injection molding machine,
The controller monitors the measurement pulse value based on the encoder output, so that the measurement pulse value enters the predetermined vibration width range indicating the damped vibration region before completion of the table rotation, and then the predetermined pulse width If the value within the predetermined rotation limit determination width range that is set smaller than the vibration width range is continuously maintained for a predetermined time, it is determined that the rotation of the rotary table is stopped, and the operation of the next step is started. Let

  In the present invention, the measurement pulse value by the encoder output is monitored, and after the measurement pulse value falls within the predetermined vibration width range that indicates the damped vibration area before the table rotation is completed, the measurement pulse value is determined from the predetermined vibration width range. If the value within the predetermined rotation limit determination width range set to a small width is continuously maintained for a predetermined time, it is determined that the rotation of the rotary table is stopped. A predetermined rotation limit determination width range is set to determine that the rotation table is small and that the rotation table is surely transitioning toward the static state, and the measured pulse value falls within this rotation limit determination width range. After that, if the value of the rotation limit determination width range is continuously maintained for a predetermined time, it is determined that the rotation of the rotary table is stopped. Therefore, the ejection operation is started immediately after the rotation is determined to be stopped. Even if, since the turntable is in the true stop position to outline targets, possibly causing galling and eject pin and insertion hole is eliminated. In other words, since the static approximate state that can be almost regarded as the completion of the rotation of the rotary table can be detected with high reliability, even if the operation of the next process such as the ejection process is started immediately after it is determined that the rotation has been completed, the next process will be hindered. It becomes possible to execute without. Further, the molding cycle can be shortened as compared with the case where the next process is started after the damping vibration of the rotary table is completely finished.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 to 7 relate to an injection molding machine according to an embodiment of the present invention (hereinafter referred to as the present embodiment). The injection molding machine of the present embodiment has two molds on a rotary table at intervals of 180 °. It is a machine that is mounted and configured to intermittently rotate the turntable 180 degrees alternately in forward and reverse directions.

  FIG. 1 is a side view of an essential part showing a movable die plate, a rotary table, and the like in the injection molding machine of the present embodiment. In FIG. 1, 1 is a movable die plate that can move back and forth between a tail stock (not shown) (holding member on which a mold opening / closing drive source and the like is mounted) and a fixed die plate (not shown), and 2 is fixed to the tail stock. A tie bar that spans between and guides the movable die plate 1, 3 is a table holding plate fixed to the movable die plate 1, and 4 is rotatably held by the table holding plate 3. The rotary table 5 is two movable molds attached (mounted) to the rotary table 4 at intervals of 180 °, 6 is a servo motor for rotating the table mounted on the movable die plate 1, and 7 is A small-diameter driving pulley (toothed pulley = timing pulley) fixed to the output shaft of the servo motor 6, 8 is a diagram in which the rotation of the driving pulley 7 is fixed to the rotary table 4. Timing belt for transmitting the large-diameter driven pulley, not (toothed pulley = timing pulley) (toothed belt), 9 is rotatable support roller that serves as an auxiliary member for supporting the weight of the rotary table 4.

  The rotary table 4 is intermittently rotated in the forward and reverse directions by 180 ° alternately by a rotational driving force of the servo motor 6 through a deceleration rotation transmission system using a timing pulley and a timing belt. In the injection molding machine of the present embodiment, two fixed molds (not shown) are attached (mounted) at 180 ° intervals to a fixed die plate (not shown), and the movable mold 5 There are two injection units corresponding to each of the pair of fixed molds. Each time the rotary table 4 is rotated by 180 °, the combination of the movable side mold 5 and the fixed side mold is alternately changed and the injection is performed simultaneously by the two injection units (respectively different resins in the two injection units). The injection molding machine of this embodiment is a machine capable of performing two-color molding.

  FIG. 2 is a block diagram showing a configuration of the rotation control system of the rotary table 4 and a configuration for performing a rotation stop determination process of the rotary table 4. In FIG. 2, reference numeral 11 denotes a system controller that controls the entire injection molding machine. The system controller cooperates with hardware resources such as arithmetic functional elements and memories and software resources such as various application software stored in advance. By the operation, various processing such as various arithmetic processing, data writing / calling processing, display control processing, command output processing and the like are executed. In FIG. 2, only functional blocks directly related to the present invention are drawn in the system controller 11. Details of these functional blocks will be described later, but each functional block includes the above hardware resource, software resource, and the like. The functional block in the system controller 11 may have a function in which one functional block also functions as another functional block.

  In FIG. 2, reference numeral 12 denotes a servo driver that drives and controls the servo motor 6 according to a command signal from the system controller 11, and 13 is attached to the servo motor 6 to detect and measure the rotation amount of the servo motor 6. An encoder that outputs a pulse value (here, an absolute encoder that outputs an absolute value of the rotation angle), 14 is a decelerated rotation transmission system (deceleration) using the timing pulley and timing belt that transmit the rotation of the servo motor 6 to the rotary table 4. Rotation transmission mechanism).

  In the system controller 11, 21 is an overall control unit that controls each part in the system controller 11, and 22 stores control conditions for table rotation control during molding operation under the control of the overall control unit 21. A table rotation control unit 23 that outputs a drive command signal to the servo driver 12 based on control target data in a table rotation control condition storage unit (not shown), a measurement pulse value output from the encoder 13, etc. Under the control, a display control unit 24 for displaying various screens on a display device (not shown) monitors the measurement pulse value output from the encoder 13, and the measurement pulse value is a damped vibration region before the table rotation is completed. The vibration range determination unit 25 that determines whether or not the vehicle has entered the predetermined vibration range A set, and outputs the determination result to the overall control unit 21, The measurement pulse value output from the encoder 13 is monitored, and the measurement pulse value is set to be smaller than the vibration width range A (the vibration width of the damped vibration of the rotary table 4 is reduced, and the rotary table 4 is reduced). , A rotation limit determination width range determination unit 26 for determining whether or not the vehicle has entered a predetermined rotation limit determination width range B (which is set to determine that the transition to the steady state is surely made) This is a stable time measuring timer that is set or reset by a set / reset signal from the rotation limit determination width range determination unit 25 and outputs a time-up signal to the overall control unit 21 when a predetermined time has been counted after being set. .

  Next, the determination process of the rotation stop of the turntable 4 of this embodiment is demonstrated using FIG. FIG. 3 is a flowchart showing the flow of the table rotation stop determination process in the present embodiment.

  When the rotation start timing of the rotary table 4 is reached, a rotation start command is output from the overall control unit 21 to the table rotation control unit 22, and the servo motor 6 is moved in a predetermined direction via the servo driver 12 by the table rotation control unit 22. The rotary table 4 is rotationally driven, and thereby the rotary table 4 is rotationally driven in a predetermined direction via the deceleration rotation transmission system 14. Then, the measurement pulse value from the encoder 13 that detects the rotation amount of the servo motor 6 is acquired by the vibration width range determination unit 24 and the rotation limit determination width range determination unit 25, and the vibration width range determination unit 24 and the rotation limit determination width are obtained. The range determination unit 25 monitors each measured pulse value (step S1). In step S2 following step S1, it is determined in the vibration width range determination unit 24 whether or not the measurement pulse value has entered a vibration width range A indicating a damped vibration region before completion of table rotation, and the measurement pulse value is determined to be within the vibration width range. If A is entered (YES in step S2), the process proceeds to step S3. If not, the process in step S2 is repeated. In step S3, the overall control unit 21 gives a command to the display control unit 23 to display a numerical value indicating completion of rotation in the display state of the operation status monitoring screen of the rotary table (for example, a numerical value display of a measured pulse value). Is fixedly displayed as a numerical value obtained by rotating the rotary table by just 180 °).

  In step S4 following step S3, in the rotation limit determination width range determination unit 25, the measurement pulse value is reduced so that the vibration width of the damped vibration of the rotary table 4 becomes small, and the rotary table 4 is reliably shifted toward the static state. It is determined whether or not it has entered the rotation limit determination range B for determining that it is present, and if the measured pulse value enters the rotation limit determination range B (if YES is determined in step S4), the process proceeds to step S5. If not, the process of step S4 is repeated. In step S5, it is determined whether or not the stable time measurement timer 26 is in an unset state. If it is in an unset state (reset state) (YES in step S5), the process proceeds to step S6. After setting the stable time measurement timer 26, the process proceeds to step S7, and when it is not in the unset state (when NO is determined in step S5), the process proceeds to step S7.

  In step S7, the rotation limit determination width range determination unit 25 determines whether or not the measurement pulse value is out of the rotation limit determination width range B. If the measurement pulse value is not out of the rotation limit determination width range B, If NO is determined in step S7, the process proceeds to step S9, and if the measured pulse value is outside the rotation limit determination range B (YES determination is made in step S7), the process proceeds to step S8 to measure the stable time. After resetting the timer 26, the process returns to step S4.

  In step S9, it is determined whether or not the stable time measurement timer 26 has timed up. If the time has not expired (NO in step S9), the process returns to step S7. If YES is determined in step S9), the overall control unit 21 regards that the table rotation is completed, and immediately instructs the ejection control unit (not shown) to start the ejection operation to start the ejection operation.

  FIG. 4 is a diagram illustrating the vibration width range A, the rotation limit determination width range B, and the measurement pulse value 31. FIG. 4 schematically illustrates the transition of the measurement pulse value 31 along the time axis. Has been. 5 shows an angle range A ′ of the turntable 4 corresponding to the vibration width range A and an angle range B ′ of the turntable 4 corresponding to the rotation limit determination width range B. In FIG. The angle range A ′ and the angle range B ′ are exaggerated.

  When the turntable 4 rotates to approximately 180 °, the turntable 4 has a large inertia due to the weight of the mold and the mounted mold, and the turntable 4 is attenuated before it completely stops rotating. As shown in FIG. 4, the measurement pulse value 31 indicates a transition of damped vibration. In the present embodiment, the fact that the rotary table is rotated to approximately 180 ° and the measured pulse value 31 is within a predetermined predetermined vibration width range A indicating the damped vibration region before the rotation is stopped The width range determination unit 24 recognizes it. Further, the measurement pulse value 31 has entered the rotation limit determination width range B for determining that the vibration width of the damped vibration of the rotary table 4 is reduced and the rotary table 4 is surely making a transition toward the steady state. The rotation limit determination width range determination unit 25 recognizes this, and after the measurement pulse value 31 enters the rotation limit determination width range B, the measurement pulse value 31 continuously follows the value within the rotation limit determination width range B. Whether or not the predetermined time Ts has been maintained is recognized by the output of the stable time measurement timer 26. Then, at the time t1 when the stable time measurement timer 26 has timed up, the overall control unit 21 regards the rotation of the turntable 4 as being stopped, and immediately starts the operation of the next step, the ejection step.

  Here, in the present embodiment, the pulse value (number of pulses) necessary for the rotation table 4 to rotate just 180 ° is 40374 pulses, the vibration range A is set to 88 pulses, and the rotation limit The judgment width range B is set to 35 pulses. Since one pulse corresponds to 0.004458 °, 88 pulses are 0.3923 ° and 35 pulses are 0.1560 °, so that the angle range A ′ = 0.3923 ° and the angle range B ′ = 0. It will be 1560 °. The predetermined time Ts is set to Ts = 0.2 seconds.

  Further, in this embodiment, the pin diameter of the eject pin that is driven to be ejected in the ejecting process is determined to be 25 mm by design value, and the hole diameter of the insertion hole through which the eject pin passes is determined to be 27 mm by design value. Then, there is a margin of 2 mm between the eject pin and the insertion hole. In the injection molding machine of the present embodiment, when the angle at the location where the eject pin is arranged is converted to mm, 0.01 ° corresponds to 0.03615 mm, and 35 pulses (rotation limit determination range B) is 0.1560 °. Therefore, 0.1560 ° corresponds to 0.56 mm at the position of the eject pin (by the way, 88 pulses (vibration width range A) corresponds to 0.3923 °, so 0.3923 ° corresponds to 0.38 ° of the eject pin). Corresponding to 1.418 mm in position). Therefore, in the present embodiment, the rotation limit determination width range B corresponds to 0.56 mm with respect to the gap of 2 mm according to the design value between the eject pin and the insertion hole. It is as a specification that saw. The reason for this is that even if there is an error that is unavoidable in manufacturing due to the dimensions of the eject pin and the insertion hole, or the assembly is performed with rough accuracy, the ejector operation can be performed without any problem. This is to make it possible.

  FIG. 6 shows an example of an environment setting screen displayed on a display device (not shown) of the injection molding machine according to the present embodiment. By calling this environment setting screen, the user of the injection molding machine can change the vibration width range. The vibration width range A and the rotation limit determination width range B can be confirmed by the numerical value displayed on the pulse number display section 41 of A and the numerical value displayed on the pulse number display section 42 of the rotation limit determination width range B. it can. In addition, by calling the environment setting screen of FIG. 6, the user of the injection molding machine confirms the time Ts by the numerical value displayed on the display unit 43 of the time Ts required for the stable time measurement timer 26 to time up. be able to.

  As described above, in the present embodiment, the measurement pulse value by the encoder 13 is monitored, and after the measurement pulse value falls within the set predetermined vibration width range A indicating the damped vibration region before the table rotation is completed, If the value within the predetermined rotation limit determination width range B that is set smaller than the predetermined vibration width range A is continuously maintained for a predetermined time, it is determined that the rotation of the turntable 4 is stopped. That is, a predetermined rotation limit determination width range B is set to determine that the vibration width of the damped vibration of the rotary table 4 is reduced and that the rotary table 4 is surely transitioning toward the static state. When the value of the rotation limit determination width range B is continuously maintained for a predetermined time after the measurement pulse value enters the rotation limit determination width range B, it is determined that the rotation of the turntable 4 is stopped. So this time Even immediately to start the eject operation after determining that stopped, the rotation table 4 is the true stop position to outline targets, possibly causing galling and eject pin and insertion hole is eliminated. That is, since a statically approximated state that can be almost regarded as the completion of the rotation of the turntable 4 can be detected with high reliability, even if the operation of the next process such as the ejection process is started immediately after it is determined that the rotation is completed, the next process is performed. It becomes possible to execute without trouble. Further, the molding cycle can be shortened as compared with the case where the next step is started after the damping vibration of the turntable 4 is completely finished.

It is a principal part side view which shows a movable die plate, a rotary table, etc. in the injection molding machine which concerns on one Embodiment of this invention. It is a block diagram which shows the structure etc. which perform the determination process of the rotation control system of a rotary table, the rotation stop of a rotary table, etc. in the injection molding machine which concerns on one Embodiment of this invention. It is a flowchart which shows the flow of the determination process of a table rotation stop in the injection molding machine which concerns on one Embodiment of this invention. It is explanatory drawing which shows the vibration width range, rotation limit determination width range, and measurement pulse value for demonstrating the determination method of the rotation stop of a turntable in the injection molding machine which concerns on one Embodiment of this invention. It is explanatory drawing which shows the angle range corresponding to the vibration width range and rotation limit determination width range of FIG. It is explanatory drawing which shows the example of an environment setting screen in the injection molding machine which concerns on one Embodiment of this invention. It is explanatory drawing which shows the vibration range and the measurement pulse value for demonstrating the determination method of the rotation stop of a rotary table in a prior art. It is explanatory drawing which shows the angle range corresponding to the vibration width range of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Movable die plate 2 Tie bar 3 Table holding plate 4 Rotary table 5 Movable side mold 6 Servo motor for table rotation drive 7 Drive pulley 8 Timing belt 9 Support roller 11 System controller 12 Servo driver 13 Encoder 14 Deceleration rotation transmission system 21 Supervision Control section 22 Table rotation control section 23 Display control section 24 Vibration width range determination section 25 Rotation limit determination width range determination section 26 Stabilization time measurement timer A Vibration width range B Rotation limit determination width range

Claims (3)

In an injection molding machine in which a plurality of molds are mounted on a rotary table at predetermined angular intervals and the rotary table is intermittently rotated by a predetermined angle,
An encoder for detecting the amount of rotation of a motor that rotationally drives the rotary table, and a controller that controls the operation of the injection molding machine,
The controller monitors the measurement pulse value based on the encoder output, and when the measurement pulse value continuously maintains a value within a predetermined rotation limit determination range for a predetermined time, the rotation of the rotary table is stopped. An injection molding machine characterized by determining and starting the operation of the next step. In an injection molding machine in which a plurality of molds are mounted on a rotary table at predetermined angular intervals and the rotary table is intermittently rotated by a predetermined angle,
An encoder for detecting the amount of rotation of a motor that rotationally drives the rotary table, and a controller that controls the operation of the injection molding machine,
The controller monitors the measurement pulse value based on the encoder output, so that the measurement pulse value enters the predetermined vibration width range indicating the damped vibration region before completion of the table rotation, and then the predetermined pulse width If the value within the predetermined rotation limit determination width range that is set smaller than the vibration width range is continuously maintained for a predetermined time, it is determined that the rotation of the rotary table is stopped, and the operation of the next step is started. An injection molding machine characterized in that The injection molding machine according to claim 2,
The controller monitors the measurement pulse value based on the encoder output, and after the measurement pulse value falls within a predetermined vibration width range that indicates a damped vibration region before completion of table rotation, the controller rotates. An injection molding machine characterized in that a display indicating the completion of rotation is performed in the display state of the operating state monitoring screen of the table.

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