JP2014144480A - Injection apparatus, injection apparatus control method and molding product manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an injection apparatus in which operation based on malfunction detection is performed adequately.SOLUTION: An injection apparatus 1 includes a sleeve 3 connecting to a cavity 105, a plunger 5 which extrudes molding material (molten metal) in the sleeve 3 to a cavity 105, a drive mechanism (an injection cylinder 9, a hydraulic device 11 and a drive device 13) which can drive the plunger 5, and a control device 153 which controls the drive mechanism. The drive mechanism includes an electric motor 23. The control device 153 performs low-speed injection by driving the electric motor 23, detects a malfunction based on load of the electric motor 23 in a constant speed area (t1 to t2) of the low-speed injection (Step S11 to S13), and, when a malfunction is detected in plural cycles, performs processing of standing a stop flag (Step S16) which is not performed in a case of detecting a malfunction only in one cycle.

Description

  The present invention relates to an injection device for a molding machine, a method for controlling the injection device, and a method for manufacturing a molded product. The molding machine is, for example, a die casting machine or an injection molding machine.

  An injection device is known in which a plunger that pushes a molding material in a sleeve into a cavity is driven by a drive mechanism including an electric motor (for example, Patent Document 1). Patent Document 1 discloses an injection device (die casting machine) that detects the torque of an electric motor and determines that there is an abnormality when the detected torque exceeds a predetermined threshold value. And when this abnormality is detected, this injection device stops its operation.

JP 2012-110930 A

  However, even if the torque shows an abnormal value, after that, when the lubricant is supplied to the plunger and the next cycle is performed, the torque often returns to the normal value. Therefore, with the technique of Patent Document 1, there is a risk of unreasonably reducing the operating rate.

  Therefore, it is desirable to provide an injection apparatus, an injection apparatus control method, and a molded article manufacturing method that are suitably operated based on abnormality detection.

  An injection device according to an aspect of the present invention includes a sleeve that communicates with a cavity, a plunger that pushes the molding material in the sleeve into the cavity, a drive mechanism that can drive the plunger, and a control device that controls the drive mechanism. The drive mechanism includes an electric motor, and the control device performs low-speed injection by driving the electric motor, detects an abnormality based on a load of the electric motor in a constant speed region of low-speed injection, When an abnormality is detected in a plurality of cycles, a predetermined process when an abnormality occurs in a plurality of cycles, which is not performed when an abnormality is detected only in one cycle, is performed.

  Preferably, when the abnormality is detected in a plurality of consecutive cycles, the control device performs the processing when the abnormality occurs in the plurality of cycles, and when the abnormality is not detected in the plurality of consecutive cycles, the occurrence of the abnormality in the plurality of cycles Do not perform time processing.

  Preferably, when an abnormality is detected in each cycle, the control device performs a predetermined single cycle abnormality occurrence process that does not include a process of stopping the transition to the next cycle.

  Preferably, the single cycle abnormality occurrence process includes a process of determining whether or not there is an abnormality in at least one of a lubrication device that lubricates the plunger and a cooling device that cools the plunger.

  Preferably, the single-cycle abnormality occurrence process includes a process for notifying abnormality, and the multiple-cycle abnormality occurrence process includes a process of stopping the transition to the next cycle.

  Preferably, when all the electric motors included in the drive mechanism are driven at a rated output, the advance force of the plunger is 1/10 or more and 3/10 or less of the maximum shot output.

  Preferably, when the output of the electric motor reaches a rated output, the control device performs processing for notifying that fact.

  An injection apparatus control method according to an aspect of the present invention is a control method for an injection apparatus that injects a molding material into a cavity by a driving force of a drive mechanism including an electric motor, and performs low-speed injection by driving the electric motor. A low-speed injection process, a detection process for detecting an abnormality based on the load of the motor in a constant speed region in the low-speed injection process, and an abnormality detected only in one cycle when an abnormality is detected in multiple cycles And a multi-cycle abnormality occurrence processing step for performing a predetermined plural-cycle abnormality occurrence process, which is not performed in the case of the above.

  A method of manufacturing a molded product according to an aspect of the present invention is a method of manufacturing a molded product by injecting a molding material into a cavity by a driving force of a drive mechanism including an electric motor, and driving the electric motor at a low speed A low-speed injection process, a detection process for detecting an abnormality based on the load of the motor in a constant speed region in the low-speed injection process, and an abnormality in only one cycle when an abnormality is detected in a plurality of cycles A multi-cycle abnormality occurrence processing step for performing a predetermined plural-cycle abnormality occurrence process, which is not performed when the error is detected.

  According to the present invention, the operation based on the abnormality detection is suitably performed.

The schematic diagram which shows the structure of the principal part of the die-casting machine which concerns on embodiment of this invention. The figure explaining operation | movement of the injection device of the die-casting machine of FIG. The figure which shows a part of FIG. 2 in detail. The flowchart which shows the procedure of the process which the control apparatus of the die-casting machine of FIG. 1 performs. The flowchart which shows the procedure of the cause discrimination | determination process of FIG.4 S18.

  FIG. 1 is a cross-sectional view schematically showing a configuration of a main part of a die casting machine DC1 according to an embodiment of the present invention.

  In the following, the left side in FIG. 1 (the direction in which the plunger 5 moves when the molten metal is pushed out into the cavity 105 by the plunger 5) may be referred to as the front, and the right side in FIG.

  The die casting machine DC1 includes, for example, a mold clamping device 151 that clamps the fixed mold 101 and the movable mold 103, and a cavity 105 that includes the fixed mold 101 and the movable mold 103 that are clamped to the mold clamping device 151. An injection device 1 for injecting and filling a molten metal (a molten metal material) as a molding material, and an unillustrated extrusion device for extruding the molded die-cast product (molded product) from the fixed mold 101 or the moving mold 103; And a control device 153 for controlling these devices. Note that the control device 153 may be regarded as constituting a part of each device.

  The mold clamping device 151 is, for example, a base (not shown), a fixed die plate 155 fixed on the base and holding the fixed mold 101, and movable in the mold opening / closing direction on the base. And a movable die plate (not shown) for holding.

  An injection frame 157 is fixed to the fixed die plate 155. The injection frame 157 is originally for fixing the injection cylinder of the injection device. However, as will be described later, in the present embodiment, the injection frame 157 is used for other purposes. The injection frame 157 may be an appropriate type such as a C type or a D type.

(Configuration of injection device)
The injection device 1 includes a sleeve 3 that communicates with the cavity 105, a plunger 5 that pushes the molten metal in the sleeve 3 to the cavity 105, an intermediate rod 7 that is coupled to the plunger 5, an injection cylinder 9 that drives the intermediate rod 7, and an injection A hydraulic device 11 that supplies hydraulic fluid to the cylinder 9 and a drive device 13 that drives the intermediate rod 7 are provided.

  The configuration of the sleeve 3 and the plunger 5 may be the same as a known configuration. The sleeve 3 is provided so as to be inserted through the fixed die plate 155, for example. The sleeve 3 may be inserted through the fixed mold 101. The plunger 5 has a plunger tip 5a that slides on the sleeve 3, and a plunger rod 5b fixed to the plunger tip 5a.

  When the molten metal is supplied into the sleeve 3 from the hot water supply port 3 a formed in the sleeve 3, the plunger tip 5 a slides (moves forward) in the sleeve 3 toward the cavity 105, so that the molten metal enters the cavity 105. Injection and filling.

  The intermediate rod 7 is for enabling the plunger 5 to be driven from a position away from the rear. In other words, the drive device 13 can be disposed rearward from the sleeve 3. The intermediate rod 7 has an axial rod body 7 a and a contacted portion 7 b for connection with the drive device 13.

  The rod body 7 a is disposed coaxially with the plunger 5, and the tip thereof is connected to the rear end of the plunger 5 by a coupling 15. The rod body 7a is inserted through the injection frame 157.

  The material, the cross-sectional shape, and the cross-sectional area of the rod body 7a may be appropriately set so that the strength necessary for injection can be obtained. For example, the rod main body 7 a is made of metal like the plunger 5, has a circular cross-sectional area, and has a diameter equal to or greater than that of the plunger 5.

  The length of the rod body 7a may also be appropriately set according to the distance at which the drive device 13 is desired to be separated from the sleeve 3. For example, the rod body 7a may be shorter or longer than the plunger 5 or its stroke.

  The abutted portion 7b is provided, for example, behind the center position of the rod body 7a, and is formed in a flange shape. The abutted portion 7b may be formed integrally with the rod body 7a, or may be formed as a separate member and fixed to the rod body 7a with a screw or the like.

  For example, the coupling 15 may be the same as that used in the conventional injection device for connecting the plunger 5 and the piston rod of the injection cylinder. In this case, the configuration of the tip of the intermediate rod 7 is the same as the configuration of the tip of the piston rod of the conventional injection cylinder.

  A bush 159 is provided on the injection frame 157 to support the intermediate rod 7. The bush 159 is a cylindrical member made of metal, for example, and is fixed to the injection frame 157. The intermediate rod 7 is inserted into the bush 159 and supported by the bush 159 so as to be slidable in the axial direction.

  The injection cylinder 9 is composed of, for example, a single-acting cylinder device, and is fixed to the cylinder portion 17, a piston 19 that can slide inside the cylinder portion 17, and the piston 19, and is exposed from the cylinder portion 17. And a piston rod 21.

  The cylinder part 17 is, for example, a cylindrical body having a circular internal cross-sectional shape. The inside of the cylinder portion 17 is partitioned by a piston 19 into a rod side chamber 17r on the piston rod 21 side and a head side chamber 17h on the opposite side. By supplying the working fluid to the head side chamber 17h, the piston 19 can move forward (move toward the plunger 5).

  The injection cylinder 9 is, for example, arranged coaxially (in series) behind the intermediate rod 7. The front end of the piston rod 21 is connected to the rear end of the intermediate rod 7. The cylinder part 17 is installed so that it cannot move. Accordingly, when the piston 19 advances in the cylinder portion 17, the driving force is transmitted to the plunger 5 through the intermediate rod 7, and the plunger 5 advances in the sleeve 3.

  The intermediate rod 7 and the piston rod 21 may be connected by an appropriate method. For example, a male screw portion is formed at the rear end of the intermediate rod 7, a female screw portion is formed at the tip of the piston rod 21, and the male screw portion is screwed to the female screw portion, whereby the intermediate rod 7 is connected to the piston rod 21. ing.

  Since the intermediate rod 7 is interposed between the plunger 5 and the injection cylinder 9, the cylinder portion 17 is positioned rearward from the conventional one. That is, conventionally, the front end portion of the cylinder portion is fixed to the injection frame 157. In the present embodiment, the cylinder portion 17 is disposed away from the injection frame 157.

  Although not particularly shown, the hydraulic pressure device 11 includes, for example, a tank that stores hydraulic fluid, a pump that delivers hydraulic fluid in the tank, an electric motor that drives the pump, and an accumulator that holds accumulated hydraulic fluid. Yes. In addition, although not particularly illustrated, the hydraulic device 11 includes a plurality of valves that appropriately connect a tank, a pump, an accumulator, and an injection cylinder 9 and control the flow of hydraulic fluid therebetween.

  For example, the hydraulic device 11 can advance the piston 19 by supplying hydraulic fluid from the accumulator to the head side chamber 17h. At this time, the flow rate of hydraulic fluid flowing out from the rod side chamber 17r or the head side chamber The speed of the piston 19 can be controlled by controlling the flow rate of the hydraulic fluid flowing into 17h by the flow rate control valve.

  The driving device 13 is driven in the front-rear direction by the driving force transmitted from the electric motor 23, the transmission mechanism 25 that transmits the driving force of the electric motor 23, and can be attached to and detached from the intermediate rod 7. And an attaching / detaching portion 27.

  The electric motor 23 is, for example, a rotary electric motor. The electric motor 23 may be a direct current motor or an alternating current motor, and may be an induction motor or a synchronous motor. The electric motor 23 is preferably an electric motor with a brake. The electric motor 23 is configured as a servo motor, and constitutes a servo mechanism together with an encoder 29 that detects the rotation of the electric motor 23 and a servo amplifier 31 that supplies electric power to the electric motor 23. The electric motor 23 may be arranged with the output shaft directed in any direction. For example, the electric motor 23 is arranged with the output shaft parallel to the piston rod 21.

  As the electric motor 23, one having an appropriate output may be selected. In the present embodiment, as will be described later, since the high-speed injection and pressure increase that require a large radiant output is performed by the hydraulic device 11, an electric motor having a relatively small output can be selected as the electric motor 23. For example, as the electric motor 23, the electric motor may be selected so that the forward force of the plunger 5 when driven at the rated output is 1/10 or more and 3/10 or less of the maximum injection output of the injection device 1.

  Note that the rated output can be specified, for example, from the specifications of the electric motor 23 or the injection device 1 or from the description. The rated output may be specified by performing a test of the electric motor 23 according to a general test method. Similarly, the maximum output power can be specified from the specifications or instructions of the injection device 1.

  In addition to transmitting the driving force of the electric motor 23, the transmission mechanism 25 also converts the rotation of the electric motor 23 into a translational motion. The transmission mechanism 25 includes, for example, a first pulley 33 that is fixed to the output shaft of the electric motor 23, a belt 35 that is hung on the first pulley 33, a second pulley 37 on which the belt 35 is hung, A screw shaft 39 to which the pulley 37 is fixed and a nut 41 screwed to the screw shaft 39 are provided. Note that the screw shaft 39 and the nut 41 constitute, for example, a ball screw mechanism.

  The screw shaft 39 is disposed in parallel to the piston rod 21. Further, the screw shaft 39 is supported by a bearing (not shown) or the like, so that movement in the axial direction (front-rear direction) is restricted and rotation about the axis is allowed. On the other hand, the nut 41 is fixed to the attaching / detaching portion 27 and the like, so that rotation around the axis is restricted and movement in the front-rear direction is allowed.

  Accordingly, the rotation of the electric motor 23 is transmitted to the screw shaft 39 via the first pulley 33, the belt 35 and the second pulley 37, and when the screw shaft 39 rotates, the nut 41 moves in the front-rear direction.

  The detachable portion 27 includes a base 43, a hook 45 that is swingably supported by the base 43, and an actuator 47 that drives the hook 45.

  The base 43 is fixed to the nut 41. Accordingly, the base 43 is driven in the front-rear direction together with the nut 41 by the driving force of the electric motor 23. Further, the hook 45 and the actuator 47 supported by the base 43 are also moved in the front-rear direction by the movement of the base 43 in the front-rear direction.

  The base portion 43 has, for example, a plate-like portion having a hole portion through which the rear end of the intermediate rod 7 (rod body 7a) is inserted, and can contact the contacted portion 7b from the rear. is there. In other words, the base 43 is prevented from moving forward relative to the piston rod 21 by contact with the contacted portion 7b, and is allowed to move backward relative to the piston rod 21 from the contact position.

  Therefore, the plunger 5 can be advanced by advancing the base 43 in a state where the base 43 is in contact with the contacted portion 7b. That is, the plunger 5 can be advanced by the driving force of the electric motor 23. Further, the plunger 5 can be moved forward relative to the base 43 by supplying hydraulic fluid to the head side chamber 17h and moving the piston rod 21 at a relatively high speed.

  The base portion 43 has a buffer portion 49 made of a material having a smaller coefficient of restitution with the abutted portion 7b than the other portions of the base portion 43 as a portion that abuts against the abutted portion 7b. Is preferred.

  For example, the hook 45 is formed in an approximately L shape, and one end is rotatably supported by the base 43. The hook 45 is engaged with the contacted portion 7b in the retracting direction of the plunger 5 ("ON" position), and is disengaged ("OFF" position). Can be moved between. Note that the hook 45 can sandwich the contacted portion 7b with the base portion 43 at the ON position.

  When the hook 45 is turned off (disengaged), the plunger 5 can be moved forward relative to the attaching / detaching portion 27. Further, when the hook 45 is turned on (engaged), the plunger 5 can be retracted as the attaching / detaching portion 27 is retracted. That is, the plunger 5 can be moved backward by the driving force of the electric motor 23.

  For example, the drive device 13 is configured and arranged so that the hook 45 can be engaged with the contacted portion 7b over the entire stroke of the piston 19. For example, the stroke of the nut 41 is equal to the stroke of the injection cylinder 9, and the drive device 13 is arranged so that the nut 41 is also located in the backward limit when the piston 19 is located in the backward limit.

  The actuator 47 is constituted by an actuator that reciprocates (extends or contracts from another viewpoint), for example. The actuator 47 is, for example, a linear motor, a pneumatic cylinder, or a hydraulic cylinder. As the actuator 47 reciprocates, the hook 45 is turned on or off.

  For convenience of illustration, the driving device 13 is shown below the injection cylinder 9, but the driving device 13 is not limited to the lower side of the injection cylinder 9, but is located on the side or upper side of the injection cylinder 9. Also good. For convenience of illustration, both the screw shaft 39 and the electric motor 23 are shown below the injection cylinder 9, but the screw shaft 39 is located on the side of the injection cylinder 9 while the electric motor 23 is below the injection cylinder 9. The positional relationship of each member in the driving device 13 such as being positioned above may be set as appropriate.

  The injection device 1 further includes a plunger lubrication device 51 and a tip cooling water supply device 53.

  The plunger lubrication device 51 supplies a lubricant for reducing the sliding resistance between the plunger tip 5 a and the sleeve 3 to the plunger tip 5 a or the sleeve 3. The specific configuration may be a known appropriate one. For example, the plunger lubrication device 51 may move the nozzle from the hot water supply port 3 a into the sleeve 3 before injection to inject the lubricant into the sleeve 3, or via a dedicated supply port formed in the sleeve 3. The lubricant may be supplied to the surface of the plunger tip 5a before injection, or the lubricant may be supplied to the surface of the plunger tip 5a before or during injection through a supply path formed inside the plunger 5. Alternatively, the lubricant may be supplied to the surface of the plunger tip 5a from the rear end side of the sleeve 3 before injection.

  The plunger lubrication device 51 has a function of diagnosing whether or not an abnormality has occurred in itself. For example, the plunger lubrication device 51 has a flow sensor (not shown) that measures the flow rate of the lubricant in the flow path for sending the lubricant, and detects an abnormality based on the detected value. More specifically, for example, the plunger lubricating device 51 determines that there is an abnormality when the detected flow rate falls below a predetermined threshold. In addition, for example, the plunger lubrication device 51 has a liquid level sensor that detects the liquid level of a tank (not shown) that stores the lubricant, and detects an abnormality based on the detected value. More specifically, for example, the plunger lubrication device 51 determines that an abnormality has occurred when the detected liquid level falls below a predetermined threshold.

  The chip cooling water supply device 53 supplies cooling water for cooling the plunger chip 5a to a flow path (not shown) formed in the plunger chip 5a. Further, like the plunger lubrication device 51, the tip cooling water supply device 53 has a function of diagnosing whether or not an abnormality has occurred in itself. For example, the chip cooling water supply device 53 has a flow sensor (not shown) that measures the flow rate of the cooling water in the flow path for sending the cooling water, and detects an abnormality based on the detected value. More specifically, for example, the chip cooling water supply device 53 determines that there is an abnormality when the detected flow rate falls below a predetermined threshold.

  The control device 153 includes, for example, a CPU 161, a memory 163, an input unit 165, and an output unit 167. The control device 153 outputs a control signal for controlling each unit based on various input signals.

  A signal is input to the control device 153, for example, an input device 169 that receives an input operation of an operator (user), an encoder 29, a servo amplifier 31, a position sensor 55 for detecting the position of the plunger 5, and an appropriate position. 1 are a pressure sensor (not shown) for detecting the pressure of the hydraulic fluid, a plunger lubrication device 51, and a tip cooling water supply device 53.

  The control device 153 outputs a signal, for example, a display device 171 for displaying information to an operator, a servo amplifier 31, a hydraulic device 11, an actuator 47 (or a driver thereof), a plunger lubrication device 51, and a chip cooling water supply. Device 53.

  The position sensor 55 forms a linear encoder together with a scale unit (not shown), for example. For example, the position sensor 55 is fixedly provided near the intermediate rod 7, and the scale portion is provided on the intermediate rod 7 and extends in the axial direction thereof. Then, the position sensor 55 indirectly detects the position of the plunger 5 by detecting the position of the scale portion that moves together with the intermediate rod 7. The position sensor 55 or the control device 153 can detect the speed by differentiating the detected position.

  For example, the servo amplifier 31 outputs information on the current value of the power supplied to the electric motor 23 to the control device 153. Control device 153 can identify the torque generated by electric motor 23 based on the current value. Note that the torque generated by the electric motor 23 is equal to the sum of the acceleration torque and the load torque (including friction torque). Therefore, in the constant speed region, the specification of the torque generated by the electric motor 23 is equivalent to the specification of the load.

  As described above, the plunger lubrication device 51 and the tip cooling water supply device 53 can detect their own abnormality, and output information on the presence or absence of the abnormality to the control device 153.

(Operation of injection device)
FIG. 2 is a diagram for explaining the operation of the injection apparatus 1. In FIG. 2, the horizontal axis indicates time. A solid line Lv indicates a change in injection speed, and a solid line Lp indicates a change in injection pressure. In the graph in which the solid lines Lv and Lp are drawn, the vertical axis indicates the magnitude of the injection speed and the injection pressure. Further, below the graph, operations of the electric motor 23, the attaching / detaching portion 27, and the hydraulic device 11 are shown. In the lower part of FIG. 2, the load of the electric motor 23 is shown.

  In general, the injection device 1 performs low-speed injection (t0 to t2), high-speed injection (t2 to t4), pressure increase (t4 to t5), and pressure holding (t5 to t7) in this order. That is, in the initial stage of injection, the injection device 1 advances the plunger 5 at a relatively low speed in order to prevent entrainment of the melt air, and then fills the melt without delaying the solidification of the melt. In view of the above, the plunger 5 is advanced at a relatively high speed. Thereafter, in order to eliminate sink marks in the molded product, the injection device 1 increases the pressure of the molten metal in the cavity by the force in the direction in which the plunger 5 moves forward, and maintains the pressure until the molten metal solidifies. Specifically, it is as follows.

(Low speed injection: t0 to t2)
When a predetermined injection start condition is satisfied, for example, the fixed mold 101 and the movable mold 103 are clamped by the mold clamping device 151 and the molten metal is supplied to the sleeve 3 through the hot water supply port 3a. Be started.

  The low speed injection is performed by the driving force of the electric motor 23. Specifically, for example, the control device 153 controls the electric motor 23 so that the rotation speed of the electric motor 23 becomes a predetermined target value. In this control, for example, feedback control is performed. Further, the target value is set to a constant value within a predetermined range defined by distance or time, for example. In the example of FIG. 2, the target value is constant in the range from the retreat limit of the plunger 5 to the high-speed switching position (or the range excluding the range necessary for initial acceleration from the range).

  The driving force of the electric motor 23 is transmitted to the plunger 5 through the transmission mechanism 25, the attaching / detaching portion 27, and the intermediate rod 7 (contacted portion 7b). The plunger 5 moves forward at a constant speed (t1 to t2) after a speed rising period (t0 to t1).

  During this time, the detachable portion 27 may be ON (engaged) or OFF (engaged). FIG. 2 exemplifies a case where it is turned off. When the attaching / detaching portion 27 is ON, for example, when multistage control including deceleration is performed, it is possible to prevent the plunger 5 from moving away from the base portion 43 due to inertial force.

  Further, during the low-speed injection, the hydraulic device 11 appropriately eliminates the excess and deficiency of the hydraulic fluid in the rod side chamber 17r and the head side chamber 17h that are generated as the piston 19 advances. For example, the hydraulic device 11 returns the working fluid discharged from the rod side chamber 17r whose volume is reduced to the head side chamber 17h via a run-around circuit (not shown) or receives it in a tank (not shown). Further, the hydraulic device 11 supplies hydraulic fluid from a tank (not shown) or a pump (not shown) to the head side chamber 17h whose volume is increased, for example. The supply of the hydraulic fluid by the pump may be such that the negative pressure in the head side chamber 17h is quickly eliminated, or may be such that the driving of the plunger 5 by the electric motor 23 is assisted.

(High-speed injection: t2 to t4)
High-speed injection is performed by the driving force of the hydraulic device 11. Specifically, for example, the control device 153 controls the hydraulic device 11 so as to supply a high-pressure hydraulic fluid from an accumulator (not shown) to the head side chamber 17h. Further, the control device 153 turns off (detaches) the detachable portion 27 from the low-speed injection, or turns off the detachable portion 27 that was ON in the low-speed injection.

  As a result, the piston 19, the piston rod 21, the intermediate rod 7 and the plunger 5 move forward at a relatively high speed. At this time, since the engagement of the detachable portion 27 is released, the plunger 5 or the like moves forward leaving the detachable portion 27 and the nut 41 moving at a relatively low speed. Therefore, the drive device 13 does not become a load that prevents the plunger 5 or the like from moving forward. Then, the molten metal in the sleeve 3 is injected into the cavity 105 at a high speed (t2 to t3).

  After that, when the molten metal is filled into the cavity 105 to some extent, the plunger 5 receives the reaction force from the filled molten metal and decelerates, while the injection pressure increases rapidly (t3 to t4). . In order to alleviate the impact at the time of filling, appropriate deceleration control may be performed by reducing the amount of hydraulic fluid supplied from the hydraulic device 11 or the like.

(Intensification and holding pressure: t4 to t7)
The pressure increase and pressure holding are performed by the driving force of the hydraulic device 11 following the high speed injection. Specifically, for example, the control device 153 uses the rod side chamber 17r as a tank pressure and controls the hydraulic device 11 so that the working fluid of an accumulator (not shown) is supplied to the head side chamber 17h. As a result, the pressure in the head side chamber 17h increases until it becomes equal to the pressure in the accumulator. That is, pressure increase is performed. Further, the pressure is maintained by maintaining the state.

  Thereafter, when the molten metal solidifies, the holding pressure is finished. For example, the control device 153 controls the hydraulic device 11 so as to stop the supply of the hydraulic pressure to the head side chamber 17h (t7). Note that the control device 153 determines whether or not the molten metal has solidified as appropriate. For example, the control device determines whether or not the molten metal has solidified based on whether or not a predetermined time has passed since a predetermined time such as the time when the final pressure is obtained.

  When the pressure holding is completed, the mold is opened by the mold clamping device 151, and the die-cast product is pushed out of the mold by an unillustrated extrusion device.

(Plunger retracted: after t7)
Although not shown in FIG. 2, the plunger 5 is retracted by the driving force of the electric motor 23, for example. Specifically, first, the rotation of the electric motor 23 is continued even after the low-speed injection ends (t2 to t). The pressure increase is started and the speed of the plunger 5 is decreased, and further, the pressure holding is started and the plunger 5 is stopped, whereby the detachable portion 27 catches up with the contacted portion 7b. Thereafter, the detachable portion 27 is turned on (engaged). Then, the control device 153 rotates the electric motor 23 in a direction opposite to the rotation direction at the time of low-speed injection at an appropriate time after the pressure holding is completed, thereby retracting the plunger 5.

  During the plunger retreat, the hydraulic device 11 appropriately eliminates the excess or deficiency of the hydraulic fluid in the rod side chamber 17r and the head side chamber 17h caused by the retraction of the piston 19. For example, the hydraulic device 11 circulates the hydraulic fluid discharged from the head side chamber 17h to the rod side chamber 17r, and receives surplus hydraulic fluid in a tank (not shown).

  FIG. 3 is an enlarged view showing the injection speed and the load on the electric motor 23 around t0 to t2 in FIG.

  A solid line Ln indicates the load of the electric motor 23 at the normal time. As described above, the low speed injection is performed by the electric motor 23. In a normal case, the load temporarily increases in the rising region (t0 to t1) where acceleration torque is required, and then becomes a constant value in the constant speed region (t1 to t2). In the high-speed injection (t2 to t2), since the plunger 5 is driven by the hydraulic device 11, the load of the electric motor 23 is only the load generated in the transmission mechanism 25.

  A two-dot chain line La indicates the load of the electric motor 23 at the time of abnormality. When the plunger tip 5a is galling or the like, the load at the time of abnormality becomes higher than that at the normal time. Also, the load varies in the constant speed region.

  Therefore, by determining whether or not the load of the electric motor 23 exceeds a predetermined reference load (threshold) and / or whether or not the fluctuation amount of the load of the electric motor 23 exceeds a predetermined reference fluctuation amount (threshold). The presence or absence of abnormality can be determined.

  These threshold values may be appropriately set by the manufacturer or operator of the injection apparatus 1 based on the trial operation of the injection apparatus 1 or data of other injection apparatuses. For example, the rated output of the electric motor 23 may be used as the reference load. When calculating the load torque from the current value of the electric motor 23 as described above, the load torque is converted into an output using the rotation speed, or the rated output is converted into torque, and the load and the rated output are compared. To do.

  Even if the sliding resistance in the rising region is normal, fluctuation between cycles and / or fluctuation within the cycle is relatively large. On the other hand, when the sliding resistance in the constant speed region is normal, the fluctuation between cycles and the fluctuation within the cycle are relatively small. Therefore, the presence / absence of abnormality can be accurately determined by making the above determination based on the load of the electric motor 23 in the constant speed region.

  FIG. 4 is a flowchart illustrating a procedure of processing executed by the control device 153 including processing related to abnormality detection as described above.

  Steps S1 to S9 shown on the left side of FIG. 4 mainly show procedures related to the basic operation of the die casting machine DC1, and steps S10 to S18 shown on the right side of FIG. 4 mainly show procedure of processing related to abnormality detection. Yes. Steps S2 and S7 surrounded by a dotted line are processes related to the mold clamping apparatus 151, and other processes are processes related to the injection apparatus 1 or the entire die casting machine DC1. Specifically, it is as follows.

  In step S1, the operation of the die casting machine DC1 is started. For example, when the operator performs a predetermined operation on the input device 169, the control device 153 is instructed to start a repeated molding cycle.

  Steps S <b> 2 to S <b> 7 show an outline of the processing procedure for one cycle of molding.

  Specifically, first, the control device 153 controls the mold clamping device 151 to perform mold closing and mold clamping (step S2). Next, the control device 153 supplies molten metal melted in a furnace (not shown) using a hot water supply device (not shown) into the sleeve 3 through the hot water supply port 3a. Next, the control device 153 controls the injection device 1 to start low-speed injection (step S3). Thereafter, the control device 153 determines whether or not the plunger 5 has reached the high speed switching position based on the detection value of the position sensor 55 (step S4). If it is determined that the plunger 5 has reached, high speed injection is performed (step S5). . Thereafter, the control device 153 performs pressure increase and pressure holding (step S6), and performs mold opening when the molten metal solidifies (step S7). Then, the die-cast product is taken out.

  When the cycle ends, the control device 153 determines whether or not the stop flag is set by the process related to the abnormality detection shown on the right side of FIG. 4 (step S8). If the control device 153 determines that the stop flag is not set, the control device 153 returns to step S2 and starts the next cycle. On the other hand, when determining that the stop flag is set, the control device 153 stops the transition to the next cycle (step S9). That is, the operation of the die casting machine DC1 is stopped.

  Although not particularly illustrated, the control device 153 includes a plunger lubrication device 51 and a tip cooling water supply device 53 so that the lubricant is supplied to the plunger 5 and the cooling water is circulated in the plunger 5 at an appropriate time. To control. For example, the control device 153 may, after each cycle, after step S7 (after step S1 in the first cycle), before the molten metal is supplied into the sleeve 3, or until low-speed injection is started. The plunger lubricating device 51 is controlled to supply the lubricant to the plunger 5 at an appropriate time. Further, for example, the control device 153 controls the chip cooling water supply device 53 so that the cooling water is circulated before the first cycle is started, and then the cooling water is circulated over a plurality of cycles. .

  The processes related to abnormality detection in steps S10 to S18 are performed in parallel with the basic operation. Specifically, it is as follows.

  In step S10, the control device 153 determines whether or not the injection process has reached a constant speed region for low speed injection. If the control device 153 determines that the constant speed region has been reached, the control device 153 proceeds to step S11.

  The determination may be made based on appropriate parameters. For example, the detection speed of the plunger 5 based on the detection value of the position sensor 55 may be determined based on whether or not the predetermined low speed injection constant speed (target value) has been reached. Further, for example, the acceleration may be performed based on whether or not the acceleration based on the detection value of the position sensor 55 has converged within a predetermined range. Further, for example, the position of the plunger 5 based on the detection value of the position sensor 55 may be determined based on whether or not the position where the constant speed region should be started is reached.

  In step S11, the control device 153 starts detecting the load of the electric motor 23. Specifically, for example, the control device 153 acquires information on the current supplied to the electric motor 23 from the servo amplifier 31 at predetermined time intervals and stores the information in the memory 163.

  Thereafter, when it is determined in step S4 that the high-speed switching position has been reached, the control device 153 ends the acquisition and storage of the information (step S12). As described above, the control device 153 acquires and stores information on the load of the electric motor 23 only for the constant speed region of the low speed injection.

  In step S13, the control device 153 determines whether or not an abnormality has occurred based on the acquired information on the load of the electric motor 23 in the constant speed region of the low speed injection. That is, as described with reference to FIG. 3, it is determined whether or not the load of the electric motor 23 exceeds a predetermined reference load and / or whether or not the fluctuation amount exceeds a predetermined reference fluctuation amount. .

  If the control device 153 determines that no abnormality has occurred, the control device 153 proceeds to step S14 and drops (or does not raise) the stop flag. In this case, as already described, the next cycle is started (No in step S8).

  On the other hand, if it is determined that an abnormality has occurred, the control device 153 proceeds to step S15 and determines whether or not the determination that such an abnormality has occurred has continued over a plurality of cycles. Note that the number of cycles serving as a threshold in this determination may be appropriately set based on experience or the like by the manufacturer or operator of the injection apparatus 1. Further, when the number of cycles from the start of operation (step S1) is less than the number of cycles in this determination, it is determined that it is not continuous over a plurality of cycles.

  When the controller 153 determines that the abnormality determination is not continuous over a plurality of cycles, the control device 153 proceeds to step S14 and drops (or does not raise) the stop flag. Therefore, similarly to the case where it is determined that no abnormality has occurred, the next cycle is started (No in step S8).

  On the other hand, if the control device 153 determines that the abnormality determination is continuous over a plurality of cycles, the control device 153 proceeds to step S16 and sets a stop flag. In this case, as already described, the transition to the next cycle is not performed (Yes in step S8 and step S9).

  As described above, the control device 153 does not stop the machine even if an abnormality based on the load of the electric motor 23 is detected only in one cycle, and stops the machine only when the abnormality is detected continuously over a plurality of cycles. I do.

  Further, the control device 153 performs a process for notifying the operator that the abnormality has occurred continuously over a plurality of cycles (step S17). This notification process is, for example, a process of displaying a specific character or a specific graphic on the display device 171, a process of lighting or blinking a lamp (not shown), or a process of outputting a specific sound from a speaker or bell (not shown). It is.

  If it is determined in step S13 that an abnormality has occurred in the load of the electric motor 23, the control device 153 proceeds to step S18 and performs processing for determining the cause.

  FIG. 5 is a flowchart showing a specific procedure of step S18.

  In step S <b> 21, the control device 153 determines whether or not an abnormality has occurred in the cooling water circulation of the plunger 5. This determination is performed, for example, by acquiring the abnormality determination result by the chip cooling water supply device 53 already described. And when it determines with abnormality having arisen, the process for alert | reporting that is performed (step S22).

  In step S23 performed in parallel with step S21, the control device 153 determines whether or not an abnormality has occurred in the supply of the lubricant to the plunger 5. This determination is performed, for example, by acquiring the abnormality determination result by the plunger lubrication device 51 already described. And when it determines with abnormality having arisen, the process for alert | reporting that is performed (step S24).

  In step S25, the control device 153 determines whether or not at least one of the abnormality of the cooling water and the abnormality of the lubricant has occurred. If it is determined that no abnormality has occurred, it is determined that an abnormality in the load of the electric motor 23 has occurred due to another cause, and processing for notifying that effect is performed (step S26).

  Note that the notification in steps S22, S24, and S26 may be performed through the visual sense of the worker using the display device 171 or the like, as in step S17, or through the auditory sense of the worker using a speaker (not shown). It may be done. Further, both notifications in steps S22 and S24 may be performed for the same cycle.

  The notifications in steps S22, S24, and S26 notify the cause of the abnormality of the load on the motor, and naturally, indirectly notify that the load on the motor 23 is abnormal. Of course, in steps S22, S24, and S26, or separately from steps S22, S24, and S26 after the Yes determination in step S13, it is directly notified by text or voice that an abnormality has occurred in the load of the motor 23. May be.

  In the determination of the presence / absence of abnormality in step S13, as already described, the rated output of the electric motor 23 may be used as the reference load (threshold). In this case, the indirect or direct notification of load abnormality as described above indirectly reports that the load of the electric motor 23 has reached the rated output. Of course, it may be notified directly that the load of the electric motor 23 has reached the rated output.

  As described above, in the present embodiment, the injection device 1 includes the sleeve 3 that communicates with the cavity 105, the plunger 5 that pushes the molding material (molten metal) in the sleeve 3 into the cavity 105, and the drive mechanism (injection) that can drive the plunger 5. A cylinder 9, a hydraulic device 11 and a driving device 13), and a control device 153 for controlling the driving mechanism. The drive mechanism includes an electric motor 23. The controller 153 performs low speed injection by driving the motor 23, detects an abnormality based on the load of the motor 23 in the constant speed region (t1 to t2) of the low speed injection (steps S11 to S13), and in a plurality of cycles When an abnormality is detected, a process of setting a stop flag (step S16) is performed that is not performed when an abnormality is detected only in one cycle.

  Therefore, for example, the problem that the machine is stopped even when the next cycle is normally performed by lubricating the plunger 5 before the next cycle is solved. As a result, the operating rate is not unreasonably lowered.

  In the present embodiment, when an abnormality is detected in each cycle (Yes in Step S13), the control device 153 includes a predetermined process (Step S18: S21 to S21) that does not include a process for stopping the transition to the next cycle. S26) is performed.

  Therefore, for example, it is possible to quickly cope with the possibility of an abnormality that requires the machine to stop while suppressing an unreasonable decrease in the operating rate. As a result, for example, a balance between machine maintenance and securing of the operating rate is suitably maintained.

  Moreover, in this embodiment, the process when abnormality is detected in each cycle described above is a process of determining whether or not there is an abnormality in at least one of the plunger lubrication device 51 and the tip cooling water supply device 53 (steps S21 and S23). Including.

  Therefore, it is possible to identify the cause of the abnormality in the load of the electric motor 23. As a result, an early response to the possibility of an abnormality that requires a machine stop is appropriately and quickly performed. As a result, it is expected to improve the operation rate after ensuring machine maintenance.

  Further, in the present embodiment, the forward force of the plunger 5 when the electric motor 23 is driven at the rated output is 1/10 or more of the maximum shot output (realized by the hydraulic device 11 in the present embodiment) 3/10. It is as follows. That is, the output of the electric motor 23 is relatively small.

  Therefore, when the plunger 5 is galling or the like and its resistance is relatively large, the plunger 5 stops. As a result, the plunger 5 is forcibly driven to prevent the plunger 5 or the sleeve 3 from being deformed.

  In the above embodiment, the combination of the injection cylinder 9, the hydraulic device 11, and the drive device 13 is an example of a drive mechanism that can drive the plunger of the present invention, and a process of setting a stop flag in step S16, step S9. Each of the machine stop and the notification process in step S17 is an example of a process when an abnormality occurs in a plurality of cycles, and the cause determination process in step S18 is an example of a process when an abnormality occurs in a single cycle of the present invention.

  The present invention is not limited to the above embodiment, and may be implemented in various aspects.

  The molding machine is not limited to a die casting machine. For example, the molding machine may be another metal molding machine, an injection molding machine, or a molding machine that molds a material obtained by mixing wood powder with a thermoplastic resin or the like. . Further, the molding machine is not limited to horizontal mold clamping horizontal injection, and may be vertical mold clamping vertical injection or horizontal mold clamping vertical injection, for example. The hydraulic fluid is not limited to oil and may be water, for example.

  The drive mechanism including the electric motor is not limited to one including an electric system and a hydraulic system (such as an injection cylinder). For example, the drive mechanism may have a hydraulic system, such as a low-speed injection motor and a high-speed injection motor, and may be all-electric.

  In the case where the drive mechanism includes an electric system and a hydraulic system, the drive mechanism is not limited to one having an attaching / detaching portion. For example, the drive mechanism may have a configuration that does not have a detachable portion in the embodiment (a configuration in which a nut and a piston rod are fixed), or a configuration that moves the entire injection cylinder back and forth by an electric system. Alternatively, the electric system may push the rear end of the piston of the injection cylinder.

  In addition, when the drive mechanism includes an electric system and a hydraulic system, the division of roles may be set as appropriate. For example, in the embodiment, low-speed injection and plunger retraction are performed by the electric system, and high-speed injection and pressure increase are performed by the hydraulic system, but pressure increase is performed by the electric system, and plunger retraction is performed by the hydraulic system. May be. Moreover, you may perform the tracking of the plunger at the time of extrusion of a molded article which is not described in embodiment by an electric system or a hydraulic system.

  The injection cylinder is not limited to a single-acting type, and may be a pressure increasing type. For example, an injection cylinder has a cylinder portion having a small diameter portion and a large diameter portion, an injection piston fixed to a piston rod and sliding on the small diameter portion, and a small diameter portion and a large diameter portion sliding behind the injection piston. It may have a booster piston.

  The electric motor is not limited to a rotary type, and may be a linear motor. In the case of a linear motor, the driving force of the linear motor may be directly transmitted to the plunger without using a transmission mechanism.

  When the electric motor is a rotary type, the conversion mechanism that converts the rotation of the electric motor into translational motion is not limited to a screw mechanism, and may be a rack and pinion mechanism, for example. The screw mechanism may be used so that the screw shaft moves in the front-rear direction.

  A gear mechanism may be interposed between the rotary electric motor and a conversion mechanism (such as a screw mechanism) that converts the rotation into translational motion instead of the pulley / belt mechanism. Moreover, you may connect an electric motor and a conversion mechanism directly, such as integrating or connecting the output shaft and screw shaft of an electric motor.

  A plurality of electric motors that perform low-speed injection may be provided. For example, in the embodiment, the plurality of second pulleys 37 are fixed coaxially to the screw shaft 39, and the driving force of the plurality of electric motors 23 is transmitted to the screw shaft 39 via the plurality of first pulleys 33 and the belt 35. May be. For example, in the embodiment, a plurality of drive devices 13 may be provided in parallel.

  When a plurality of electric motors that perform low-speed injection are provided, the forward force of the plunger when all of the electric motors are driven at the rated output is 1/10 or more and 3/10 or less of the maximum injection power. May be selected as follows.

  The determination of whether or not an abnormality has been detected in a plurality of cycles is not limited to the determination made on a plurality of consecutive cycles. For example, even if not consecutive, when an abnormality is detected at a certain frequency, processing when an abnormality occurs in multiple cycles such as a machine stop may be performed. However, if an abnormality is detected in multiple consecutive cycles, the process leading to the execution of the process when the multiple cycle abnormality occurs is simplified, and the machine must be stopped, etc. It is possible to reliably perform an appropriate process in a situation with high characteristics.

  In the embodiment, the load is recorded in time series in the constant speed region of low-speed injection, and the presence or absence of abnormality is determined based on the data, but each time load information is acquired while in the constant speed region, The presence or absence of abnormality may be determined (the presence or absence of abnormality may be determined in real time). Further, the abnormality determination may be performed based on the load in the constant speed region, and the load acquisition itself or the load recording itself may be performed outside the constant speed region.

  The determination as to whether or not the output (load) of the motor has reached the rated output and the notification based on the determination result are irrelevant to the abnormality detection (step S13) related to the multi-cycle abnormality occurrence process and the single cycle abnormality occurrence process May be done. For example, an appropriate threshold different from the rated output is used in step S13, and it is determined whether the load (converted to output) of the motor exceeds the rated output in real time during steps S11 to S12. Notification based on the determination result may be made.

  Further, whether or not the output has reached the rated output may be determined in a range including other speed regions in addition to the constant speed region for low speed injection, or in regions other than the constant speed region for low speed injection. May only be done.

  The multi-cycle abnormality occurrence process may be any process that is not performed in the single-cycle abnormality occurrence process, and is not limited to a process including a machine stop. For example, the process at the time of occurrence of a multi-cycle abnormality may be only a process for displaying a character or graphic different from the character or graphic displayed in the process at the time of occurrence of a single-cycle abnormality.

  The process at the time of occurrence of a single cycle abnormality is not limited to the process including determining the cause of the abnormality of the load and notifying, as long as the process does not include the machine stop. For example, the single cycle abnormality occurrence process may be a process of increasing the lubricant or increasing the flow rate of the cooling water.

  DESCRIPTION OF SYMBOLS 1 ... Injection apparatus, 3 ... Sleeve, 5 ... Plunger, 23 ... Electric motor, 105 ... Cavity, 153 ... Control apparatus.

Claims (9)

A sleeve leading to the cavity;
A plunger for pushing the molding material in the sleeve into the cavity;
A drive mechanism capable of driving the plunger;
A control device for controlling the drive mechanism;
Have
The drive mechanism includes an electric motor,
The control device includes:
Low speed injection is performed by driving the electric motor,
Detecting an abnormality based on the load of the electric motor in a constant speed region of low-speed injection;
An injection device that performs predetermined multi-cycle abnormality occurrence processing that is not performed when an abnormality is detected in only one cycle when an abnormality is detected in a plurality of cycles. The control device performs the multi-cycle abnormality occurrence process when an abnormality is detected in a plurality of consecutive cycles, and performs the multi-cycle abnormality occurrence process when no abnormality is detected in a plurality of consecutive cycles. The injection device according to claim 1. 3. The injection device according to claim 1, wherein, when an abnormality is detected in each cycle, the control device performs a predetermined single-cycle abnormality occurrence process that does not include a process of stopping the transition to the next cycle. The injection apparatus according to claim 3, wherein the processing when the single cycle abnormality occurs includes a process of determining whether or not there is an abnormality in at least one of a lubricating device that lubricates the plunger and a cooling device that cools the plunger. The single cycle abnormality occurrence process includes a process for notifying abnormality,
The injection device according to claim 3 or 4, wherein the processing at the occurrence of an abnormality in the plurality of cycles includes processing for stopping transition to the next cycle. The forward movement force of the plunger when all the electric motors included in the drive mechanism are driven at a rated output is 1/10 or more and 3/10 or less of the maximum shot output. The injection device according to. The injection device according to claim 6, wherein when the output of the electric motor reaches a rated output, the control device performs a process of notifying that fact. A method for controlling an injection device that injects a molding material into a cavity by a driving force of a driving mechanism including an electric motor,
A low speed injection process for performing low speed injection by driving the electric motor;
A detection step of detecting an abnormality based on a load of the electric motor in a constant speed region in the low-speed injection step;
When an abnormality is detected in a plurality of cycles, a plurality of cycle abnormality occurrence processing steps for performing a predetermined multiple cycle abnormality occurrence process, which is not performed when an abnormality is detected only in one cycle,
Control method of injection device having A method of manufacturing a molded product by injecting a molding material into a cavity by a driving force of a driving mechanism including an electric motor,
A low speed injection process for performing low speed injection by driving the electric motor;
A detection step of detecting an abnormality based on a load of the electric motor in a constant speed region in the low-speed injection step;
When an abnormality is detected in a plurality of cycles, a plurality of cycle abnormality occurrence processing steps for performing a predetermined multiple cycle abnormality occurrence process, which is not performed when an abnormality is detected only in one cycle,
The manufacturing method of the molded article which has this.

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