JP2004130676A - Method for controlling vertical injection molding machine and vertical injection molding machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the following problem: in a vertical injection molding machine in which a movable platen is moved vertically in relation to a lower mold by a hydraulic cylinder, when the movable platen is elevated toward an ascending target position and stopped, when the falling of the movable platen by its own weight is detected, the operation of the molding machine is stopped, and a time loss occurs until the molding machine is operated again. <P>SOLUTION: In the control of the vertical injection molding machine 1 in which the upper movable platen 7 is moved vertically in relation to a lower platen by the hydraulic cylinder 8, when the platen 7 is elevated toward the ascending target position LS-O by the hydraulic cylinder 8 and stopped, when the falling of the platen 7 from the target position LS-O is detected, the platen 7 is again elevated toward a re-ascending target position LS-OP which is set to be by a prescribed distance A higher than the position LS-O by the hydraulic cylinder 8. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a control method of a vertical injection molding machine in which an upper movable plate is moved up and down by a hydraulic cylinder with respect to a lower die, and a vertical injection molding machine.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, as a vertical injection molding machine in which an upper movable plate is raised and lowered by a hydraulic cylinder with respect to a lower die, one described in Japanese Patent Application Laid-Open No. 8-197572 (Patent Document 1) is known. According to Patent Document 1, a rotary table is rotated while a movable mold is placed on a fixed mold fixed to the rotary table, and the mold is moved to a mold clamping and injection station below the movable plate. To move. Then, the movable platen is lowered with respect to the mold to perform mold clamping, and injection filling is performed. When the injection filling is completed, only the movable platen is raised at the mold clamping and injection station. On the other hand, the mold is moved to the mold opening / closing station by the rotation of the rotary table. In the mold opening / closing station, only the movable mold is held and lifted by the mold opening / closing device, and a molded product is taken out of the fixed mold and the next insert is set.
[0003]
According to Japanese Patent Application Laid-Open No. 11-931 (Patent Document 2), one upper die is fixed to a movable plate, and a pair of lower dies is fixed to a rotatable rotary table. Then, the movable platen and the upper mold are lowered toward the lower mold, mold clamping is performed, and injection filling is performed. When the injection filling is completed, the movable platen and the upper mold are raised at the mold clamping position. On the other hand, the lower mold and the molded product left in the lower mold are rotated by 180 ° by the rotation of the rotary table. In Patent Literature 2, the mold clamping device for moving the movable plate up and down and clamping the mold is composed of a hydraulic cylinder, and is provided below the fixed plate.
[0004]
Further, according to JP-A-10-646 (Patent Document 3), a plurality of upper dies are fixed to a rotary table rotatably provided on a movable plate, and a plurality of lower dies are also fixed to a fixed plate. . Then, the movable platen and the plurality of upper dies fixed to the rotary table of the movable platen are lowered toward the plurality of lower dies, mold clamping is performed, and injection filling is performed. When the injection filling is completed, the movable platen and the plurality of upper dies fixed to the rotary table of the movable platen are raised. Thereafter, the rotary table is rotated, and the movable platen and the plurality of upper dies are lowered again with respect to the lower dies different from the last time, and the next mold clamping and injection filling are performed.
[0005]
In all of the vertical injection molding machines described in these publications, a movable platen is raised and lowered by a hydraulic cylinder. It is not desirable to raise the movable plate by the hydraulic cylinder in the molding machine to a position higher than necessary from the viewpoint of miniaturization of the mold clamping device, shortening of the molding cycle, and energy saving, and within an allowable range. It is desirable to stop at a low position. However, in the molding machine, while the movable platen is being lifted and stopped, the movable platen may slightly descend due to its own weight. This lowering of the movable plate is particularly likely to occur when oil leakage from the hydraulic circuit including the hydraulic cylinder is likely to occur due to the use of the molding machine over time. Therefore, conventionally, when the movable plate is lowered, the operation of the molding machine is stopped for the purpose of preventing the lower die being rotated and the upper die which has been lowered from colliding with each other. Therefore, the molding time until the next start of the molding machine is lost, and troubles such as labor for restarting the molding machine by an operator and deterioration of the molten resin measured and retained in the heating cylinder occur. Was.
[0006]
[Patent Document 1]
JP-A-8-197572 ((0010), (0011), (FIG. 1))
[Patent Document 2]
JP-A-11-931 ((0013), (0014), (0015), (FIG. 1))
[Patent Document 3]
JP-A-10-646 ((0010), (0011), (0012), (FIG. 1))
[0007]
[Problems to be solved by the invention]
The present invention has been made in view of the above problems, and in a vertical injection molding machine in which a movable platen is lifted and lowered by a hydraulic cylinder with respect to a lower die, a movable platen and the like are raised toward a target lift position. It is an object of the present invention to solve the problem that the operation of the molding machine is stopped when the molding machine is lowered due to its own weight during stoppage, and the time until the next operation of the molding machine is lost.
[0008]
[Means for Solving the Problems]
A control method of a vertical injection molding machine according to claim 1 is a control method of a vertical injection molding machine that raises and lowers an upper movable plate with respect to a lower plate by using a hydraulic cylinder. When the upper movable platen is moved downward from the target elevation position to the lower side while being lifted slightly above the target elevation position and stopped, the upper movable platen is raised again by a predetermined distance above the target elevation position. The hydraulic cylinder is raised again to the target position by the hydraulic cylinder.
[0009]
According to a second aspect of the present invention, in the control method of the first aspect, the operation stop position is set at a predetermined distance below the ascending target position, and the hydraulic pressure of the upper movable plate is higher than the operation stop position. When the upper movable platen is located at a position between the stroke limit of the cylinder and the upper movable platen, the upper movable platen is recognized to be in a rising completed state, and the operation is continued.
[0010]
The control method of a vertical injection molding machine according to claim 3, wherein the lower plate is provided with a plurality of lower dies fixed thereto and rotatably provided around a rotating shaft, and the upper movable plate has one upper die. When the upper movable platen is at a position between the stroke limit of the hydraulic cylinder on the ascending side of the operation stop position and the upper movable platen, the upper movable platen is recognized as being in the ascending completion state, and the rotation operation of the lower platen is started. It is characterized by being executed.
[0011]
According to a fourth aspect of the present invention, there is provided a control method for a vertical injection molding machine according to any one of the first to third aspects, wherein when the ascent target position is set and inputted from the setting section, the ascending target position and the operation stop are performed. The position is set based on a predetermined value or a predetermined relational expression.
[0012]
A vertical injection molding machine according to claim 5, wherein the vertical movable injection molding machine moves up and down the upper movable plate with respect to the lower plate by a hydraulic cylinder; A setting section for setting and inputting a target elevation of the panel, and a hydraulic cylinder is operated to move the upper movable panel to the elevation target position when the upper movable panel is lowered while being stopped at the elevation target position or slightly above the elevation target position. And a control unit for re-elevating toward a re-elevation target position set a predetermined distance above.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a side view schematically showing a vertical injection molding machine of the present invention. FIG. 2 is an explanatory diagram showing a positional relationship of set positions used for control when the upper movable platen is lifted in the vertical injection molding machine of the present invention. FIG. 3 is a flowchart showing a control method of the vertical injection molding machine of the present invention.
[0014]
The vertical injection molding machine 1 shown in FIG. 1 is for continuously molding a resin molded product, and is roughly composed of an injection device 2 and a mold clamping device 3. In the mold clamping device 3, two tie bars 5, 5 are erected outside the machine base 4, and one tie bar 5 a is erected substantially at the center of the machine base 4. An upper panel 6 is fixed above the tie bar 5a. The upper platen 6 is fixed with a hydraulic cylinder 8 serving as both a lifting means and a mold clamping means for an upper movable platen 7, and a ram 9 provided to be able to move up and down from the hydraulic cylinder 8 downward. The movable platen 7 is fixed.
[0015]
The hydraulic cylinder 8 in this embodiment is of a type generally called a booster type. Although not shown, a first cylinder for moving the upper movable platen 7 up and down at a high speed and a second cylinder for clamping the mold are provided. And are decorated. The ram 9 of the hydraulic cylinder 8 is moved up and down by controlling a solenoid valve and the like of a hydraulic circuit 11 by a control signal from a control unit 10. In this embodiment, a servo valve is not used as an electromagnetic valve, but a servo valve may be used to further improve the accuracy. The vicinity of the end of the upper movable platen 7 is inserted into the two tie bars 5, 5 and the one tie bar 5a, respectively. One upper die 12 is fixed to the lower surface of the upper movable plate 7. Therefore, the upper movable platen 7 is provided so as to be able to move up and down while maintaining a state parallel to the lower surface of the upper platen 6 as the ram 9 moves up and down. On one side of the upper movable plate 7, a rotary encoder 13 as a position detection unit for detecting a position at which the upper movable plate 7 is moved up and down is arranged. The rotary encoder 13 is connected to the control unit 10 so that a detection signal can be transmitted to the control unit 10. Although the detailed description of the hardware configuration of the control unit 10 is omitted, the control unit 10 includes a CPU, a RAM, a ROM, and a bus circuit that connects them.
[0016]
On the other hand, on the upper surface of the machine base 4, a turntable 14 serving as a lower plate is rotatably disposed around the tie bar 5a as a central axis. In this embodiment, two lower dies 15, 15 are fixed to the upper surface of the turntable 14 on both sides with the tie bar 5a as the center. The rotary table 14 is provided so as to be intermittently rotatable between a mold clamping position 16 and a molded product take-out position 17 by a motor (not shown) provided in the machine base 4. A setting unit 18 including input keys and a set value display screen is provided on the side of the machine base 4. The setting unit 18 is connected to the control unit 10, and the data set and input in the setting unit 18 is provided to be transmittable to the control unit 10.
[0017]
The structure of the vertical injection molding machine to which the control method of the present invention can be applied is not limited to the above, and may be a vertical injection molding machine as shown in Patent Documents 1 to 3. In addition, instead of a so-called rotary type in which one of the boards rotates, a vertical injection molding machine in which the same lower mold and upper mold are always clamped may be used. Further, as for the hydraulic cylinder 8, as long as the upper movable platen 7 is raised and lowered by the hydraulic cylinder 8, the mold clamping means may be performed by an operating means such as an electric motor or an electromagnet. The hydraulic cylinders 8 for raising and lowering and the mold clamping may be provided separately. Only the hydraulic cylinder 8 for raising and lowering is provided on the lower platen or the machine base 4 side, and the upper movable platen 7 is directly moved by a rod. May be raised to raise the upper movable platen 7. Alternatively, a toggle link mechanism driven by a hydraulic cylinder may be used for the mold opening / closing and mold clamping mechanisms.
[0018]
Further, the position detecting section is not limited to the rotary encoder 13 described above, and other detecting means such as a linear scale and a potentiometer may be used. Further, a detecting means such as a limit switch may be attached to each detection position. In that case, it is desirable that the position of the limit switch or the like be variably provided.
[0019]
Next, in the vertical injection molding machine 1 of the present invention, the set position used for the sequence control when the upper movable platen 7 is lifted after the mold clamping is completed will be described with reference to FIG. The vertical injection molding machine 1 according to the present invention includes, as the set positions, an ascending target position LS-O, a re-ascending target position LS-OP set a predetermined distance A above the ascending target position LS-O, and an ascending target. An operation stop position LS-OM set a predetermined distance B below the position LS-O is set. Among them, the ascending target position LS-O is a setting position set and input from an input key of the setting unit 18, and in the sequence control, the upper movable platen 7 is raised by the hydraulic cylinder 8 and stopped after the mold clamping is completed in the sequence control. This is the control target position at the time of the control. The ascending target position LS-O also has a role of detecting that the upper movable platen 7 has descended after the upper movable platen 7 has stopped at the ascending target position LS-O or slightly above the ascending target position LS-O. Have. However, in this embodiment, the actual upper movable platen 7 stops at a position slightly above the ascending target position LS-O due to inertial force. When the upper movable platen 7 is almost completely stopped at the target elevation position LS-O by using the servo valve, the upper movable platen 7 has a predetermined width of hysteresis at the target elevation position LS-O so that the upper movable plate 7 has a predetermined width. The descent may be detected when the descent has deviated from the ascending target position LS-O. The hysteresis, the distance from the re-elevation target position LS-OP to the elevation target position LS-O, and the distance from the elevation target position LS-O to the operation stop position LS-OM are determined by the size of the vertical injection molding machine 1. It is determined by the weight of the upper movable platen 7 and the like.
[0020]
The re-elevation target position LS-OP is a set position that is set based on a predetermined value or a system parameter based on a predetermined relational expression when the target elevation position LS-O is input. In this embodiment, the re-elevation target position LS-OP is set at a position 3 mm above the ascent target position LS-O. The re-elevation target position LS-OP is used when the upper movable platen 7 is re-elevated by the operation of the hydraulic cylinder 8 when it is detected that the upper movable platen 7 has descended from the ascent target position LS-O due to its own weight. Is the control target position. The re-elevation target position LS-OP is set in consideration of a margin within a range up to a stroke limit SL in the ascending direction of the upper movable platen of the hydraulic cylinder 8.
[0021]
The operation stop position LS-OM is also a set position set based on a predetermined value or a system parameter based on a predetermined relational expression when the ascending target position LS-O is input. In this embodiment, the operation stop position LS-OM is set at a position 1 mm below the ascending target position LS-O. The operation stop position LS-OM is changed to the position of the operation stop position LS-OM due to abnormal oil supply to the hydraulic cylinder 8 or abnormal detection of the position of the upper movable plate 7 by the rotary encoder 13. Alternatively, when it is detected that the rotating table 14 is lowered, the setting position is intended to stop the rotation operation or the like of the rotary table 14 serving as the lower plate. In the vertical injection molding machine 1 of the present invention, when the upper movable platen 7 is located at a position between the stroke limit SL of the hydraulic cylinder 8 on the rising side from the operation stop position LS-OM, the upper movable platen 7 is raised. The rotation operation of the turntable 14 and the like are set to be executable assuming that it is in the completed state.
[0022]
Next, a method of sequence control when the upper movable platen 7 of the vertical injection molding machine 1 according to the present invention is raised will be described with reference to the flowchart of FIG. In this embodiment, molding is performed semi-automatically. Therefore, the rotation of the rotary table is rotated by pressing the switch button when the operator finishes the insert on the side of the molded product removal position. First, before starting the molding, the set target 18 is used to input a target lift position LS-O of the upper movable platen 7. Then, as described above, in the control unit 10, the set positions of the target re-elevation position LS-OP and the operation stop position LS-OM are set by the system parameters.
[0023]
Next, molding is started. When the injection filling of the molten resin from the injection device 2 into the cavity formed between the lower mold 15 and the upper mold 12 is completed and a predetermined time has elapsed, the mold clamping by the hydraulic cylinder 8 is completed (step 1). . Next, the upper movable platen 7 is raised by the hydraulic cylinder 8 (step 2). At this time, the position of the upper movable platen 7 is continuously detected by the rotary encoder 13 which is a position detection unit, and the detected value is sent to the control unit 10 as a signal. Then, the position data of the upward target position LS-O stored in the control unit 10 is compared with the detection value detected by the rotary encoder 13 (step 3), and the upward target position LS-O is detected by the rotary encoder 13. If not (N), the upper movable platen 7 continues to rise. Further, when the ascending target position LS-O is detected by the rotary encoder 13 (Y), it is determined that the upper movable platen 7 has reached the predetermined ascending target position LS-O that is set and inputted, and the upper movable platen 7 is moved by the hydraulic cylinder 8. The ascent is stopped (step 4). However, in this embodiment, the actual upper movable platen 7 stops at a position slightly above the ascending target position LS-O due to inertial force.
[0024]
Then, in this state, it is confirmed whether or not the rotation operation button of the turntable 14 has been pressed by the operator, and whether or not a turntable rotation command has been issued (step 5). When there is no turntable rotation command (N), the position of the upper movable platen 7 is continuously detected by the rotary encoder 13 and compared with the ascending target position LS-O in the control unit 10 (step 6). When it is detected that the upper movable platen 7 has been lowered from the position of the ascending target position LS-O (Y), the hydraulic cylinder 8 is operated to raise the upper movable platen 7 again (step 7). At this time, the target position at which the upper movable platen is re-elevated is the re-elevation target position LS-OP set a predetermined distance A above the elevation target position LS-O. In this embodiment, the re-elevation target position LS-OP is higher than a position slightly higher than the elevation target position LS-O, which is the position where the upper movable platen 7 originally stopped. Then, it is detected by the rotary encoder 13 whether the upper movable platen 7 has risen to the re-elevation target position LS-OP (step 8). When the re-elevation target position LS-OP is not detected (N), the upper movable platen 7 Continue the climb. When the re-elevation target position LS-OP is detected (Y), the ascent of the upper movable platen 7 is stopped (step 9). As a result, the upper movable platen 7 is stopped at the same position as the re-elevation target position LS-OP or slightly above it.
[0025]
Then, both when the upper movable platen 7 is re-raised to the re-elevation target position LS-OP and when it is not detected that the upper movable platen 7 has descended from the ascending target position LS-O (N), Returning again to step 5, it is confirmed whether or not a turntable rotation command has been issued. When there is a rotation table rotation command (Y), the rotation of the rotation table 14 is executed (step 10). Then, it is confirmed whether or not the position of the upper movable platen 7 is higher than the operation stop position LS-OM (step 11). When the position of the upper movable platen 7 is higher than the operation stop position LS-OM (Y), the rotation of the turntable 14 is continued. Then, it is checked whether the rotation table 14 has reached the rotation end position (step 12). If the rotation table 14 has not reached the rotation end position (N), the process returns to step 10 and the rotation of the rotation table 14 is continued. It is checked whether the upper movable platen 7 is on the rising side from the operation stop position LS-OM. When the rotary table 14 reaches the rotation end position (Y), the upper movable platen 7 is lowered to close the mold (step 13), and when the end of the mold closing is confirmed, mold clamping is started (step 14). Further, in Step 11, when the position of the upper movable platen 7 detects the operation stop position LS-OM, or detects below the operation stop position LS-OM (N), the operation of the molding machine is stopped (Step 15). ).
[0026]
Therefore, in this embodiment, after the rotation of the rotary table 14 is started, even if it is detected that the upper movable platen 7 has descended from the target elevation position LS-O, the upper movable platen 7 remains in the operation stop position. As long as it is on the ascending side from LS-OM, it is recognized that the ascending is in the completed state, and the rotating operation of the turntable 14 is continued. At this time, even if the upper movable platen 7 is descending from the target elevation position LS-O, the hydraulic cylinder 8 does not perform the control for re-elevating the upper movable platen 7 to the target elevation position LS-OP. The reason is that, because the predetermined distance B is set between the target elevation position LS-O and the operation stop position LS-OM, for example, the upper movable platen 7 is lowered by about 0.1 mm per minute. This is because the upper movable platen 7 does not fall below the operation stop position LS-OM within the rotation speed of the turntable 14 (about 5 seconds). In addition, even when it is detected that the upper movable platen 7 has descended from the ascending target position LS-O while the turntable 14 is rotating, the upper movable platen 7 is moved toward the re-ascending target position LS-OP by the hydraulic cylinder 8. Control may be performed to raise the pressure again.
[0027]
The present invention can also be applied to the case where full automatic molding is performed by the vertical injection molding machine 1. In this case, the rotary table 14 may be rotated almost at the same time when the upper movable platen 7 is raised. By using the timer function 10, the rotary table 14 may be rotated after a lapse of a predetermined time from the rising of the upper movable platen 7.
[0028]
【The invention's effect】
In the control of the vertical injection molding machine that raises and lowers the upper movable plate with respect to the lower plate by a hydraulic cylinder, the upper movable plate is raised from a target position by lifting the upper movable plate to a target position for lifting by a hydraulic cylinder. When the lowering is detected, the upper movable platen is re-raised by the hydraulic cylinder to a re-elevating target position which is set a predetermined distance above the ascending target position. When the molding machine is lowered due to its own weight while stopped, the operation of the molding machine is stopped, and the problem that the molding time is lost until the next operation of the molding machine does not occur. In addition to the above, problems such as labor for the operator to restart the molding machine and deterioration of the measured molten resin are not caused.
[0029]
In addition, in the vertical rotary injection molding machine, during rotation of the rotary table, when the upper movable plate or the like is stopped at the ascending target position due to its own weight or the like, the operation such as rotation of the rotary table is stopped, The problem described above has occurred. However, in the present invention, the operation stop position is provided below the ascending target position, and when the upper movable platen is located between the stroke limit of the hydraulic cylinder on the ascending side from the operation stop position, the upper movable platen is in the lift-completed state. Since it is recognized that there is, it is possible to prevent the collision of the upper mold and the lower mold due to the rotation of the rotary table and to stop the operation such as the rotation of the rotary table. As a result, the above-described problems such as a loss of molding time do not occur.
[Brief description of the drawings]
FIG. 1 is a side view schematically showing a vertical injection molding machine of the present invention.
FIG. 2 is a diagram showing a positional relationship of a set position used for control when the upper movable platen is lifted in the vertical injection molding machine of the present invention.
FIG. 3 is a flowchart illustrating a control method of the vertical injection molding machine according to the present invention.
[Explanation of symbols]
1 Vertical injection molding machine 2 Injection device 3 Mold clamping device 4 Machine base 5, 5a Tie bar 6 Upper plate 7 Upper movable plate 8 … Hydraulic cylinder 9… Ram 10… Control part 11… Hydraulic circuit 12… Upper die 13… Rotary encoder 14… Rotary table 15… Lower die 16… Mold clamping position 17… Molded product removal Position 18 Setting part LS-O Ascent target position LS-OP Re-elevation target position LS-OM Operation stop position SL Stroke limit

Claims (5)

In a control method of a vertical injection molding machine that raises and lowers an upper movable plate with respect to a lower plate by a hydraulic cylinder,
The upper movable plate is raised by the hydraulic cylinder toward a lifting target position,
When it is detected that the upper movable platen is on the lower side from the ascending target position while stopped slightly above the ascending target position or the ascending target position,
A method for controlling a vertical injection molding machine, wherein the hydraulic cylinder is re-elevated to a re-elevation target position set a predetermined distance above an elevation target position. An operation stop position is set a predetermined distance below the ascending target position,
When the upper movable platen is located at a position between a stroke limit in the hydraulic cylinder on the ascending side from the operation stop position, the upper movable platen is recognized as being in a rising completed state,
The control method for a vertical injection molding machine according to claim 1, wherein the operation is continued. The lower plate is provided with a plurality of lower dies fixed to be rotatable about a rotation axis, and one upper die is fixed to the upper movable plate,
When the upper movable platen is at a position between the stroke limit of the hydraulic cylinder on the rising side from the operation stop position, the upper movable platen is recognized to be in a rising completed state, and the lower platen is rotated. The method for controlling a vertical injection molding machine according to claim 2, wherein the control is performed. When the climb target position is set and input from the setting unit,
The vertical injection molding machine according to any one of claims 1 to 3, wherein the re-elevation target position and the operation stop position are set based on a predetermined value or a predetermined relational expression. Control method. In a vertical injection molding machine in which the upper movable plate is raised and lowered by a hydraulic cylinder with respect to the lower plate,
A position detection unit that detects a position of the upper movable plate,
A setting unit for setting and inputting a rising target position of the upper movable plate;
When the upper movable platen is stopped at a target elevation position or slightly above the target elevation position, and the detection position of the upper movable plate detected by the position detecting means is lower than the target elevation position, the hydraulic pressure is reduced. A vertical injection molding machine, comprising: a control unit that operates a cylinder to re-raise the upper movable platen to a re-elevation target position that is set a predetermined distance above the elevation target position.

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