Injection molding apparatus

Abstract

An injection molding apparatus (70) performs injection molding in a state where a mold is clamped by a magnetic clamping device (1). The injection molding apparatus (70) comprises: a molding operation device (65); and a molding controller (90). The molding operation device (65) can register, in advance and in accordance with the mold, a plurality of clamping forces by the magnetic clamping device (1) and / or abnormality determination threshold values regarding the clamping forces. The molding controller (90) controls an injection molding operation. When the mold is clamped by the magnetic clamping device (1), the molding controller (90) performs abnormality determination of the clamping force before the injection molding operation on the basis of the registered clamping forces or abnormality determination threshold values and a clamping force measured at the time of clamping.

Description

injection molding equipment

[0001] The present invention relates to an injection molding apparatus that uses magnetism to hold a mold on an attraction surface and performs injection molding.

[0002] Patent Document 1 discloses an injection molding machine that clamps mold parts using a magnetic clamping device. The magnetic clamping device in Patent Document 1 includes a plurality of magnetic adsorption units that fix the mold. The magnetic flux applied in the magnetic adsorption units at least substantially determines the gripping force applied to the mold parts.

[0003] The magnetic clamping device includes a detection means for detecting the operating state of the magnetic clamping device. The detection means includes a coil for outputting a detection signal in response to an applied magnetic flux. The magnetic flux is continuously monitored, and the gripping force is continuously calculated based on the monitored magnetic flux. If the magnetic flux or gripping force level does not achieve a threshold, an alarm condition is triggered.

[0004] Special Publication No. 2005-515080

[0005] Many injection molding machines equipped with magnetic clamping devices are designed to accommodate interchangeable molds of various shapes. The magnetic flux that must be generated by the magnetic clamping device to obtain sufficient clamping force varies depending on the size of the mold, etc.

[0006] In this regard, Patent Document 1 does not describe changing the threshold value when the mold is replaced.

[0007] The present invention has been made in consideration of the above circumstances, and its purpose is to properly detect abnormalities in holding of a mold even when the mold is replaced in an injection molding device that uses magnetism to hold the mold on an attraction surface to perform injection molding. Means to solve the problem and effects

[0008] The problem to be solved by the present invention is as described above. Next, the means for solving this problem and the effects thereof will be explained.

[0009] According to an aspect of the present invention, there is provided an injection molding apparatus having the following configuration. That is, this injection molding apparatus performs injection molding with a mold clamped by a magnetic clamping device. The injection molding apparatus includes a molding operation device and a controller. The molding operation device is capable of registering in advance multiple clamping forces by the magnetic clamping device and / or abnormality determination thresholds related to the clamping force, depending on the mold. The controller controls the injection molding operation. The controller includes a clamping state determination unit. When the mold is clamped by the magnetic clamping device, the clamping state determination unit determines an abnormality in the clamping force before the injection molding operation, based on the registered clamping force or the abnormality determination threshold and the clamping force measured during clamping.

[0010] This allows abnormalities in the clamping force that could lead to the mold falling off to be detected before the start of injection molding. Since multiple clamping forces or abnormality judgment thresholds can be registered depending on the mold, the criteria for judging abnormalities in the clamping force can be easily changed when the mold is replaced.

[0011] The injection molding apparatus preferably has the following configuration: That is, the molding operation device can register at least one of the clamping force and the abnormality judgment threshold together with mold information in advance. The molding operation device can select the mold to be clamped from the pre-registered molds before clamping the mold. The clamping state judgment unit judges whether the clamping force is abnormal based on the clamping force or the abnormality judgment threshold stored in correspondence with the selected mold.

[0012] This allows the standard for determining whether the clamping force is abnormal to be automatically set by selecting the mold, thereby preventing setting errors.

[0013] The injection molding apparatus preferably has the following configuration: the controller includes a clamping force display unit that, when registering at least one of the clamping force and the abnormality determination threshold, causes the magnetic clamp device to clamp the mold and displays the measured clamping force.

[0014] This allows the operator to refer to the actually measured clamping force and set the clamping force or abnormality judgment threshold for clamping the mold in the injection molding machine, thereby making it possible to appropriately determine the criteria for abnormality judgment of the clamping force.

[0015] The injection molding apparatus is preferably configured as follows: That is, the molding operation device can register in advance at least one of the clamping force and the abnormality determination threshold, and molding conditions, together with mold information, including at least one of the resin temperature, mold temperature, and filling pressure.

[0016] This allows molding conditions, including the criteria for determining whether the clamping force is abnormal, to be registered in an organized manner, and the injection molding device to be operated in accordance with these conditions.

[0017] In the injection molding apparatus, the controller preferably includes an alarm unit that issues an alarm when the clamping state determination unit determines that there is an abnormality in the clamping force.

[0018] This allows the operator to quickly become aware of any abnormalities in the clamping force.

[0019] The injection molding apparatus preferably has the following configuration: the magnetic clamping device clamps the mold on both the fixed side and the movable side; the clamping force abnormality determination unit determines whether there is an abnormality in the clamping force on both the fixed side and the movable side; if the clamping force determination unit determines that there is an abnormality in the clamping force on only one of the fixed side and the movable side, the alarm issued by the alarm unit includes information indicating whether there is an abnormality in the clamping force on the fixed side or the movable side.

[0020] This allows the operator to easily understand whether an abnormality in the clamping force has occurred on the fixed side or the movable side.

[0021] FIG. 1 is a front view showing the overall configuration of an injection molding apparatus according to an embodiment of the present invention. FIG. 2 is a schematic diagram showing a first magnetic plate in a released state. FIG. 3 is a schematic diagram showing a first magnetic plate in a locked state. FIG. 4 is a block diagram showing the electrical configuration of a magnetic clamping device. FIG. 5 is a diagram showing an example of a screen displayed on a molding operation device for setting a clamping force. FIG. 6 is a diagram showing an example of a screen for selecting a mold to be mounted on the injection molding apparatus from a plurality of molds registered in advance. FIG. 7 is a diagram showing an example of a warning message displayed on a screen. FIG. 8 is a diagram showing an example of a clamping force measured when a clamping operation is performed in the magnetic clamping device.

[0022] Next, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a front view showing the overall configuration of an injection molding apparatus 70 according to an embodiment of the present invention. Fig. 2 is a side view showing the configuration of a first magnetic plate 6.

[0023] 1 includes a fixed platen 71, a movable platen 72, a mold clamping device 73, a hopper 74, a heating barrel 75, and an ejector device 76. The injection molding device 70 also includes a magnetic clamping device 1. The magnetic clamping device 1 is used to detachably fix a first mold 81 to the fixed platen 71 and a second mold 82 to the movable platen 72, respectively.

[0024] The injection molding device 70 includes a main frame 80 that is elongated in the horizontal direction. A fixed platen 71 and a mold clamping device 73 are fixed to the main frame 80. A movable platen 72 is supported via guide rods 78 so as to be slidable along the longitudinal direction of the main frame 80. The fixed platen 71 and the movable platen 72 are arranged to face each other in the longitudinal direction of the main frame 80.

[0025] The mold clamping device 73 includes an actuator (not shown). The configuration of the actuator is arbitrary, but it can be, for example, a motor or a hydraulic cylinder. The mold clamping device 73 transmits the driving force of the actuator to the movable platen 72, thereby moving the movable platen 72 in a direction toward and away from the fixed platen 71. Hereinafter, the direction in which the movable platen 72 approaches the fixed platen 71 may be referred to as the mold clamping direction D1, and the direction in which the movable platen 72 moves away from the fixed platen 71 may be referred to as the mold opening direction D2.

[0026] The hopper 74 and the heating barrel 75 are attached to the main frame 80. The hopper 74 can store granular synthetic resin material, which is the raw material for the molded product. The lower end of the hopper 74 is connected to the heating barrel 75. The heating barrel 75 is hollow. A screw (not shown) is arranged inside the heating barrel 75.

[0027] An actuator (not shown) is connected to the heating barrel 75. The actuator can move the heating barrel 75 between an advanced position where it protrudes from the fixed platen 71 toward the movable platen 72, and a retracted position. When the heating barrel 75 protrudes from the fixed platen 71, the internal space of the heating barrel 75 is connected to a cavity (not shown) that is formed inside the first mold 81 and the second mold 82 when they are closed. The synthetic resin material supplied to the heating barrel 75 is melted by heating and supplied into the cavity by being extruded by the screw. In this way, the heating barrel 75 functions as a nozzle that ejects the molten material.

[0028] After the injection molding is completed, the ejector device 76 removes the molded product from the first mold 81 and the second mold 82 in the open state.

[0029] The magnetic clamp device 1 includes a first magnetic plate 6 , a second magnetic plate 7 , a clamp controller 40 , and a clamp operating device 60 .

[0030] A first magnetic plate 6 is fixed to the fixed platen 71. Similarly, a second magnetic plate 7 is fixed to the movable platen 72. The first magnetic plate 6 and the second magnetic plate 7 are arranged to face each other in the movement direction of the movable platen 72.

[0031] Each of the first magnetic plate 6 and the second magnetic plate 7 has a flat attraction surface 25. The first mold 81 and the second mold 82, which are the targets of the clamping operation performed by the magnetic clamping device 1, are made of a magnetic material, for example, iron.

[0032] The first magnetic plate 6 can be switched between a locked state and a released state. In the locked state, a magnetic flux is generated on the attraction surface 25 of the first magnetic plate 6, and the first mold 81 is attracted to the attraction surface 25 by magnetic force. In the released state, the generation of the magnetic flux on the attraction surface 25 is stopped, and the attraction of the first mold 81 is released. The second magnetic plate 7 can also be switched between a locked state and a released state.

[0033] Since the first magnetic plate 6 and the second magnetic plate 7 have substantially the same configuration, the configuration of the first magnetic plate 6 will be described below as a representative.

[0034] The first magnetic plate 6 is formed in a plate shape. One surface in the thickness direction of the first magnetic plate 6 is fixed to a fixed plate 71, and a flat attraction surface 25 is formed on the opposite surface.

[0035] The first magnetic plate 6 includes a plurality of magnetic pole elements 10 and a plurality of proximity sensors 30. The plurality of magnetic pole elements 10 are arranged in a grid pattern.

[0036] The first magnetic plate 6 is provided with two types of magnetic pole elements 10, namely, N-pole type and S-pole type. The N-pole type means that the pole facing the attracting surface 25 of the first magnet 11 described below is the N-pole, and the S-pole type means that the pole is the S-pole. The magnetic pole elements 10 are provided on the first magnetic plate 6 so that two adjacent magnetic pole elements 10 in the vertical or horizontal direction have opposite pole types.

[0037] The N-pole type magnetic pole element 10N will be described in detail. As shown in Fig. 2, the N-pole type magnetic pole element 10N includes a first magnet 11, a second magnet 12, an electromagnetic coil 13, a detection coil 14, and a fixing member 15. The first magnet 11, the second magnet 12, the electromagnetic coil 13, the detection coil 14, and the fixing member 15 are all housed in a recess 26 formed in the first magnetic plate 6.

[0038] The first magnet 11 is a permanent magnet, such as an alnico magnet. The first magnet 11 is formed in a disk shape, and its magnetization direction coincides with the thickness direction. In the N-pole type magnetic pole element 10N, the first magnet 11 is arranged so that its N pole faces the attracting surface 25 and its S pole faces away from the attracting surface 25.

[0039] The second magnet 12 is a permanent magnet, such as a neodymium magnet. The second magnet 12 is cylindrical, and its magnetization direction is aligned with the radial direction. In the N-pole type magnetic pole element 10N, the second magnet 12 is arranged with its N pole facing outward in the radial direction and its S pole facing inward in the radial direction.

[0040] The electromagnetic coil 13 is formed by winding a thin conductor into a cylindrical shape. The electromagnetic coil 13 is disposed on the outer periphery of the disk-shaped first magnet 11. The electromagnetic coil 13 is disposed alongside the second magnet 12 in the axial direction of the magnetic pole element 10. The electromagnetic coil 13 is electrically connected to the clamp controller 40 via a cable (not shown). By passing a current through the electromagnetic coil 13 and applying a magnetic field of sufficient strength opposite to the magnetization direction of the first magnet 11, the magnetic pole of the first magnet 11 can be reversed.

[0041] The detection coil 14 is formed by winding a thin, elongated conductor in a circular shape. In this embodiment, the detection coil 14 is disposed on the outer periphery of the electromagnetic coil 13, but the position of the detection coil 14 is not limited to the above. The detection coil 14 detects magnetic flux passing through it. The number of turns of the detection coil 14 can be, for example, one turn, but may be two or more turns. Furthermore, the number of turns of the detection coil 14 does not need to be determined to be an integer multiple of one turn, and may be, for example, 1 / 2 turn, 5 / 4 turn, etc.

[0042] The fixed member 15 is formed in a generally cylindrical shape. The fixed member 15 closes the opening of the recess formed in the first magnetic plate 6. The fixed member 15 is disposed adjacent to the first magnet 11 in the axial direction of the magnetic pole element 10.

[0043] The proximity sensors 30 are non-contact sensors and can be configured as, for example, known semiconductor switches. Each proximity sensor 30 is disposed so as to be embedded in a recess 27 formed in the first magnetic plate 6. The proximity sensor 30 turns ON when the first mold 81, which is the detection target, approaches the proximity sensor 30 so close that it comes into contact with the attraction surface 25, and turns OFF otherwise.

[0044] In the S-pole type magnetic pole element 10S, the magnetization directions of the first magnet 11 and the second magnet 12 are all opposite to those of the N-pole type magnetic pole element 10N. Except for this, the configuration of the S-pole type magnetic pole element 10S is the same as that of the N-pole type magnetic pole element 10N.

[0045] Next, a description will be given of the released state and locked state of the first magnetic plate 6. The released state can be rephrased as an unclamped state, and the locked state can be rephrased as a clamped state.

[0046] In the released state, the magnetic circuit in the first magnetic plate 6 is formed as shown in FIG. 2 . Specifically, in the released state, no current flows through the electromagnetic coil 13. Therefore, when focusing on a certain N-pole type magnetic pole element 10N, the magnetic flux emitted from the N pole of the first magnet 11 passes through the second magnet 12, then passes through the adjacent S-pole type magnetic pole element 10S, in that order, through the second magnet 12 and the first magnet 11, and enters the S pole of the first magnet 11 of the original magnetic pole element 10N. In this way, in the released state, the magnetic circuit is formed in a loop inside the first magnetic plate 6, so no magnetic flux is generated on the attraction surface 25. Therefore, attraction to the first mold 81 does not occur.

[0047] When current flows through the electromagnetic coil 13 from the state shown in Figure 2, the first magnetic plate 6 switches to the locked state shown in Figure 3. Specifically, in all magnetic pole elements 10 provided on the first magnetic plate 6, the polarity of the first magnet 11 is reversed by passing a direct current through the electromagnetic coil 13. Therefore, the magnetic pole of the surface of the first magnet 11 facing the attraction surface 25 becomes the same as the magnetic pole of the inner peripheral surface of the second magnet 12. As a result, when focusing on a certain N-pole type magnetic pole element 10N, the magnetic flux starting from the N-pole of the second magnet 12 passes through the second magnet 12 of the adjacent S-pole type magnetic pole element 10S, then passes through the first mold 81, and enters the S-pole of the second magnet 12, which was the starting point. Furthermore, in the same magnetic pole element 10N, the magnetic flux emitted from the north pole of the first magnet 11 in the magnetic pole reversal state passes through the first magnet 11 of the adjacent south-pole type magnetic pole element 10S, then passes through the first mold 81 and enters the south pole of the first magnet 11 of the original magnetic pole element 10N. In this state, both the magnetic flux based on the first magnet 11 of the magnetic pole element 10N and the magnetic flux based on the second magnet 12 appear on the attraction surface 25. As a result, the first mold 81 is attracted to the attraction surface 25 by magnetic force. This magnetic force corresponds to the attraction force and clamping force described below.

[0048] Once the first mold 81 is attracted to the attraction surface 25, the locked state is stably maintained by the magnetic field lines, even if the current to the electromagnetic coils 13 is stopped. This allows energy conservation to be achieved. To return the first magnetic plate 6 from the locked state to the released state, a direct current in the opposite direction to the above is simply passed through all of the electromagnetic coils 13 provided on the first magnetic plate 6.

[0049] The second magnetic plate 7 attracts and holds the second mold 82 on the attraction surface 25 using the same principle as the first magnetic plate 6. The second magnetic plate 7 is configured substantially the same as the first magnetic plate 6, so a description thereof will be omitted.

[0050] Next, the clamp controller 40 and the clamp operating device 60 will be described.

[0051] The clamp controller 40 is configured as a known computer and includes a CPU, ROM, RAM, etc. The clamp controller 40 is electrically connected to the clamp operating device 60 and a molding controller (controller) 90. The molding controller 90 is a computer that controls each part of the injection molding device 70, and will be described in detail later.

[0052] The clamp controller 40 includes a current control unit 41 , a current acquisition unit 42 , a proximity sensor state acquisition unit 43 , a clamp state monitoring unit 44 , an abnormality output unit 45 , and an interlock control unit 46 .

[0053] The current control unit 41 controls the current flowing through the electromagnetic coils 13 provided in each of the first magnetic plate 6 and the second magnetic plate 7 .

[0054] The current acquisition unit 42 acquires the current flowing through the detection coil 14 for each of the first magnetic plate 6 and the second magnetic plate 7. An induced current is generated in the detection coil 14 in a direction that prevents changes in the magnetic flux passing through it. The magnitude of the current acquired by the current acquisition unit 42 is sampled at an appropriate frequency and an integral calculation is performed. As a result, the amount of change in the magnetic flux passing through the detection coil 14 can be obtained.

[0055] The proximity sensor state acquisition unit 43 acquires the state of the proximity sensors 30 provided on the first magnetic plate 6 and the second magnetic plate 7 .

[0056] The clamping state monitoring unit 44 monitors the clamping state of the first magnetic plate 6 and the second magnetic plate 7 based on the current flowing through the detection coil 14 and the state of the proximity sensor 30 .

[0057] When the clamp state monitoring unit 44 detects an abnormality in the first magnetic plate 6 and the second magnetic plate 7 , the abnormality output unit 45 outputs an abnormality detection signal to the forming controller 90 .

[0058] The interlock control unit 46 performs interlock control in the magnetic clamping device 1 by exchanging signals between the clamping controller 40 and the forming controller 90, for example.

[0059] For example, the interlock control unit 46 prohibits the clamping and unclamping operations of the first magnetic plate 6 and the second magnetic plate 7 unless a state indicating that the injection molding device 70 is in a clamped state is input from the molding controller 90.

[0060] For example, the interlock control unit 46 prohibits the clamping operation of the magnetic clamping device 1 unless the proximity sensor 30 is turned ON after detecting the first mold 81 or the second mold 82. This makes it possible to prevent the clamping operation from being performed when there is a gap between the suction surface 25 and the first mold 81 or the second mold 82.

[0061] The clamping force acquisition unit 47 acquires the attractive forces acting on the first magnetic plate 6 and the second magnetic plate 7 based on the change in magnetic flux detected by the detection coil 14. The attractive forces can be rephrased as the clamping force of the clamping device.

[0062] The principle of measuring the clamping force is substantially disclosed in the above-mentioned Patent Document 1, so it will be briefly explained below. When the magnetic flux φ passing through one detection coil 14 changes, an output voltage ε expressed as ε = -N(dφ / dt) is generated in the detection coil 14 according to the equation for induced electromotive force, where N is the number of turns of the detection coil 14. By integrating this output voltage ε and dividing by the number of turns N, the change in the magnetic flux φ can be estimated. Based on this change in magnetic flux and the area of ​​the coil surface of the detection coil 14, the clamping force can be estimated using a known calculation formula.

[0063] The multiple detection coils 14 of the multiple magnetic pole elements 10 are connected in series to an integrator (not shown). Before switching from the released state to the locked state, the output of the integrator is set to zero. When transitioning from the released state to the locked state, the integrator outputs a value proportional to the cumulative magnetic flux change occurring in the detection coils 14. The clamping force acquisition unit 47 obtains the clamping force based on the output value of the integrator. When obtaining the clamping force, a theoretical conversion formula or a conversion table based on experimental values ​​may be used.

[0064] The clamping force output unit 48 outputs the clamping force obtained by the clamping force obtaining unit 47 to the forming controller 90 .

[0065] The clamp operating device 60 includes a display unit 61 and an operating unit 62 .

[0066] The display unit 61 is configured by, for example, a lamp, a 7-segment LED, etc. The display unit 61 can display various information related to the magnetic clamp device 1.

[0067] The operation unit 62 is configured by, for example, hardware keys, switches, etc. The operation unit 62 can issue various instructions to the magnetic clamping device 1.

[0068] Next, the molding controller 90 and the molding operation device 65 will be described.

[0069] The molding controller 90 includes a condition storage unit 91 , a condition selection unit 93 , a clamping state determination unit 94 , an alarm unit 95 , and a clamping force display unit 96 .

[0070] The condition storage unit 91 stores, in association with one another, a mold ID that can uniquely identify a combination of a first mold 81 and a second mold 82 that can be attached to the injection molding device 70, a name registered by the user for that mold, and molding conditions that are applied when injection molding is performed using that mold. The mold name is an example of mold information. The mold name can be arbitrarily determined by the operator as long as it is a string of characters that can identify the mold; for example, the mold product number or the like may be registered. Instead of the mold name, the name of the product molded by the mold may be registered.

[0071] There are various possible molding conditions, but examples of such conditions include resin temperature, mold temperature, filling pressure, injection speed, pressure holding, injection time, cooling time, metering position, speed-pressure holding switch position, screw forward position, screw rotation speed, screw back pressure, mold opening / closing speed, mold clamping force, ejector ejection speed, ejector ejection force, and number of ejector ejections.

[0072] In the injection molding apparatus 70 of this embodiment, the molding conditions stored in the condition storage unit 91 include the clamping force of the magnetic clamp device 1. In other words, the condition storage unit 91 includes a clamping force storage unit 92 for storing the clamping force in association with the mold ID. The clamping force is registered for each of the first magnetic plate 6 side and the second magnetic plate 7 side (in other words, the first mold 81 and the second mold 82).

[0073] In this embodiment, the molding controller 90 calculates an abnormality determination threshold based on the set clamping force, and if the measured clamping force falls below this abnormality determination threshold, it is determined that there is an abnormality in the clamping force. Therefore, the clamping force value set for the injection molding device 70 essentially functions as a reference value for determining whether a clamping abnormality exists.

[0074] When attaching a new mold to the injection molding device 70, the operator of the injection molding device 70 operates the molding operation device 65 to register the mold in advance. At this time, the operator inputs the name of the mold, resin temperature, mold temperature, filling pressure, clamping force, etc. An example of the registration screen is shown in FIG. 5. As shown in FIG. 5, the registration screen includes a confirm button 101, a reset button 102, and a cancel button 103. The confirm button 101 is a button that instructs the operator to confirm the input content. The reset button 102 is a button that instructs the operator to redo the input. The cancel button 103 is a button that instructs the operator to cancel the new registration.

[0075] When the input is completed and the operator taps the confirm button 101, the molding controller 90 associates the input information with the newly issued mold ID and stores it in the condition storage unit 91. In this embodiment, the mold name input by the operator is stored in the condition storage unit 91. Alternatively, the mold name may be stored in a separate storage unit.

[0076] When multiple molds are replaced and attached to the injection molding device 70 for use, the operator can register in advance the name of each mold and the molding conditions (including the clamping force) for each mold in the molding controller 90. Figure 6 shows a state in which three molds, named "Mold A," "Mold B," and "Mold C," are registered in the injection molding device 70.

[0077] The list screen in Figure 6 displays a select button 111, a change button 112, and a delete button 113 for each of the three molds that have been registered so far. The select button 111 is a button for specifying the mold to be installed. The change button 112 is a button for instructing changes to the name, resin temperature, clamping force, etc. registered for the mold. The delete button 113 is a button for instructing deletion of the mold registration.

[0078] This list screen displays a new registration button 114 for registering a new mold. By tapping the new registration button 114, the new mold can be registered as described in FIG. 5.

[0079] The condition selection unit 93 accepts the operator's selection of one molding condition from among the multiple molding conditions registered in the condition storage unit 91. The operator operates the molding operation device 65 to select one mold to be mounted on the injection molding device 70 from the molds registered in advance. The operator taps the selection button 111 on the row of the relevant mold (e.g., mold B) from the list of molds displayed on the screen of Fig. 6. This allows the molding controller 90 to read the molding conditions of the relevant mold before clamping the first mold 81 and the second mold 82.

[0080] The clamping state determination unit 94 determines whether the first mold 81 and the second mold 82 are clamped with sufficient clamping force when they are attached to the injection molding device 70. This determination is made based on the clamping force measured by the magnetic clamping device 1 when the first mold 81 and the second mold 82 are attached and the clamping force included in the molding conditions selected by the condition selection unit 93.

[0081] The clamping state determination unit 94 determines that the clamping force is insufficient, for example, when the actually measured clamping force is insufficient even when an appropriate margin is taken into account for the clamping force determined as a molding condition. The margin can be determined as appropriate, and may be, for example, 20% of the determined clamping force.

[0082] The alarm unit 95 issues an alarm when the clamping state determination unit 94 determines that the clamping force of the magnetic clamping device 1 is insufficient. The alarm may take various forms, but a typical form is to display a warning message on the display unit 66 provided in the molding operation device 65.

[0083] An example of a warning message is shown in Fig. 7. Fig. 7 shows an example of a screen displayed on the display unit 66 when the first mold 81 and the second mold 82 are clamped by the magnetic clamping device 1. When the clamping force on only one of the fixed side and the movable side is below the abnormality determination threshold, the warning message 120 includes information specifying whether the insufficient clamping force is occurring on the fixed side or the movable side, as shown in Fig. 7. When the clamping force on both the fixed side and the movable side is below the abnormality determination threshold, the warning message 120 indicates this.

[0084] 7 includes an injection molding start button 121 and a cancel button 122. The injection molding start button 121 is a button for instructing the start of injection molding. The cancel button 122 is a button for instructing the cancellation of injection molding.

[0085] The timing for the determination by the clamp state determination unit 94 is after the magnetic clamp device 1 is switched from the released state to the locked state to attract the first mold 81 and the second mold 82, and before the start of injection molding. Therefore, if the attraction of the first mold 81 and the second mold 82 is insufficient for some reason, the operator can notice the insufficient clamping force, cancel injection molding, and check the clamp state before instructing the injection molding device 70 to start the molding operation. As a result, the first mold 81 and the second mold 82 can be prevented from falling during the molding operation.

[0086] When the operator registers the clamping force, the clamping force display unit 96 can display the measured value of the clamping force when the mold is clamped by the magnetic clamping device 1 in accordance with the operator's instructions on the display unit 66 as reference information.

[0087] The molding operation device 65 includes a display unit 66 and an operation unit 67 .

[0088] In this embodiment, the display unit 66 is configured as a known display device.

[0089] The operation unit 67 includes hardware keys and a touch panel that is integrated with the display device. The configuration of the operation unit 67 is not limited to the above, and the operation unit 67 may include, for example, an appropriate pointing device.

[0090] Next, a method for setting the clamping force in the injection molding device 70 will be described.

[0091] The clamping force included in the molding conditions can be set, for example, by an operator operating the operation unit 67 of the molding operation device 65 to directly input a numerical value on the screen shown in Fig. 5. At this time, the injection molding device 70 actually clamps the first mold 81 and the second mold 82 with the magnetic clamping device 1, and the value of the clamping force detected during this trial clamping can be displayed on the display unit 66 of the molding operation device 65. To realize this function, the molding controller 90 is provided with a clamping force display unit 96.

[0092] When setting the clamping force, the operator positions the first mold 81 and the second mold 82 adjacent to the first magnetic plate 6 and the second magnetic plate 7, and then taps the clamping force measurement button 104 in FIG. 5 to instruct clamping force measurement. The injection molding apparatus 70 is previously set in a mold clamping state. In response to this operation, the molding controller 90 outputs a clamping command to the clamp controller 40, causing the magnetic clamping device 1 to actually perform clamping. Instead of being automatically performed as described above, the clamping operation may be performed by the operator manually operating the operation unit 62 of the clamp operating device 60. After the magnetic clamping device 1 is switched from the release state to the lock state, the clamp controller 40 outputs the measured clamping force to the molding controller 90. The magnetic clamping device is switched to the release state immediately after being switched to the lock state or at an appropriate timing thereafter.

[0093] The clamping force display unit 96 provided in the molding controller 90 displays the acquired clamping force on the display unit 66 of the molding operation device 65. An example of this is shown in Fig. 8. After visually checking whether there are any abnormalities in the clamping state of the first mold 81 and the second mold 82, the operator inputs a set value for the clamping force while referring to the displayed measured value of the clamping force.

[0094] In this case, the operator can register an appropriate set value for the clamping force in the injection molding device 70 while referring to the actual measured value of the clamping force.

[0095] When the mold has a complex shape, it is difficult to accurately estimate the clamping force from its outer shape. According to this embodiment, the clamping force can be set while referring to the clamping value actually measured, thereby reliably reducing setting errors.

[0096] A copy measurement value button may be provided on the screen of Fig. 8. When the operator taps the copy measurement value button, the measured clamping force is copied to the input field for the clamping force setting value. At the same time as the clamping force is measured, the measured clamping force may be automatically copied to the input field for the clamping force setting value.

[0097] As described above, the injection molding apparatus 70 of this embodiment performs injection molding with the mold clamped by the magnetic clamping device 1. The injection molding apparatus 70 includes a molding operation device 65 and a molding controller 90. The molding operation device 65 can register in advance multiple values ​​of at least one of the clamping force by the magnetic clamping device 1 and the abnormality determination threshold value related to the clamping force, depending on the mold (i.e., the combination of the first mold 81 and the second mold 82). The molding controller 90 controls the injection molding operation. The molding controller 90 includes a clamping state determination unit 94. When the mold is clamped by the magnetic clamping device 1, the clamping state determination unit 94 determines whether the clamping force is abnormal before the injection molding operation, based on the registered clamping force and the clamping force measured during clamping.

[0098] This allows abnormalities in the clamping force that could lead to the mold falling off to be detected before the start of injection molding. Since multiple clamping forces or abnormality judgment thresholds can be registered depending on the mold, the criteria for judging abnormalities in the clamping force can be easily changed when the mold is replaced.

[0099] In the injection molding apparatus 70 of this embodiment, the molding operation device 65 can register at least one of the clamping force and the abnormality judgment threshold value together with mold information in advance. Before clamping a mold, the molding operation device 65 can select a mold to be clamped from the pre-registered molds. The clamping state determination unit 94 determines whether the clamping force is abnormal based on the clamping force or the abnormality judgment threshold value stored in association with the selected mold.

[0100] This allows the standard for determining whether the clamping force is abnormal to be automatically set by selecting the mold, thereby preventing setting errors.

[0101] In the injection molding apparatus 70 of this embodiment, the molding controller 90 includes a clamping force display unit 96. When registering a clamping force, the clamping force display unit 96 causes the magnetic clamping device 1 to clamp the mold and displays the measured clamping force.

[0102] This allows the operator to refer to the actually measured clamping force and set the clamping force when clamping the mold or the abnormality determination threshold value in the injection molding apparatus 70. Therefore, the criteria for determining abnormality in the clamping force can be appropriately determined.

[0103] In the injection molding apparatus 70 of this embodiment, the molding operation device 65 can register in advance the clamping force and molding conditions together with mold information. The molding conditions include at least the resin temperature.

[0104] This allows molding conditions, including the criteria for determining whether the clamping force is abnormal, to be registered in an organized manner, and allows the injection molding device 70 to operate in accordance with these conditions.

[0105] In the injection molding apparatus 70 of this embodiment, the molding controller 90 includes an alarm unit 95 that issues an alarm when the clamp state determination unit 94 determines that there is an abnormality in the clamp force.

[0106] This allows the operator to quickly become aware of any abnormalities in the clamping force.

[0107] In the injection molding apparatus 70 of this embodiment, the magnetic clamping device 1 clamps the mold on both the fixed side and the movable side. The clamping force abnormality determination unit 94 determines whether there is an abnormality in the clamping force on both the fixed side and the movable side. If the clamping force abnormality determination unit 94 determines that there is an abnormality in the clamping force on only one of the fixed side and the movable side, the warning message 120 displayed by the warning unit 95 includes information indicating whether the abnormality in the clamping force is on the fixed side or the movable side.

[0108] This allows the operator to easily understand whether an abnormality in the clamping force has occurred on the fixed side or the movable side.

[0109] The preferred embodiment of the present invention has been described above, but the above configuration can be modified, for example, as follows. Each modification may be made alone, or multiple modifications may be made in any combination.

[0110] 5 and 8, an operator may set an abnormality determination threshold for the clamping force instead of the clamping force. In this case, the clamp state determination unit 94 determines whether or not there is an abnormality in the clamping force by comparing the clamping force measured by the magnetic clamp device 1 with the set abnormality determination threshold.

[0111] After the clamping force is registered, the forming controller 90 commands the magnetic clamping device 1 to actually perform clamping, and the clamping state determination unit 94 determines whether the measured clamping force is sufficient compared to the registered clamping force, and the determination result may be displayed on the display unit 66 of the forming operation device 65. In this case, if there is an error in setting the clamping force, the operator can notice it at an early stage.

[0112] The alarm unit 95 may issue an alarm by sounding a buzzer (not shown) provided in the injection molding device 70, for example.

[0113] The clamping state determination unit 94 may determine whether the clamping force is excessive, instead of or in addition to determining whether the clamping force is insufficient, and if so, the alarm unit 95 may issue an alarm. This configuration increases the chances that the operator will notice a discrepancy between the mold selected by the operator on the screen of Figure 6 and the mold actually attached to the injection molding device 70.

[0114] As long as multiple clamping forces can be registered in advance, they may be registered without mold information or without other molding conditions such as resin temperature. The same applies to the configuration in which an abnormality determination threshold value for the clamping force is registered.

[0115] The function of measuring and displaying the clamping force when registering the clamping force or the abnormality determination threshold value may be omitted.

[0116] The injection molding device 70 may be configured so that, after the trial clamping described above, injection molding can be started while the locked state of the magnetic clamping device 1 is maintained.

[0117] The molding controller 90 may be provided with an interlock control unit. This interlock control unit performs control to prevent the injection molding operation of the injection molding device 70 when the clamp state determination unit 94 determines that there is an abnormality in the clamping force measured by the magnetic clamp device 1 when the mold is attached. The interlock control can be realized, for example, by disabling the injection molding start button 121 in FIG. 7.

[0118] The molding controller 90 may have a function for determining whether the registered clamping force or the measured clamping force is appropriate by referring to other molding conditions. For example, if the mold opening force setting among the molding conditions exceeds the clamping force setting, there is a high possibility that the first mold 81 or the second mold 82 will fall during mold opening. Furthermore, if the ejector ejection force setting among the molding conditions exceeds the movable clamping force setting, there is a high possibility that the second mold 82 will fall during operation of the ejector device 76. The molding controller 90 checks for such improperly set conditions in advance, and if necessary, the alarm unit 95 issues an alarm or performs interlock control to prevent the injection molding operation. This prevents the mold from falling.

[0119] DESCRIPTION OF SYMBOLS 1 Magnetic clamp device 65 Molding operation device 70 Injection molding device 90 Molding controller (controller) 81, 82 Mold

Claims

1. An injection molding apparatus which performs injection molding with a mold clamped by a magnetic clamp device, comprising: a molding operation device which can register in advance multiple values ​​for at least one of the clamping force by the magnetic clamp device and an abnormality judgment threshold related to the clamping force in accordance with the mold; and a controller which controls the injection molding operation, wherein the controller has a clamp state judgment unit which, when the mold is clamped by the magnetic clamp device, judges an abnormality in the clamping force before the injection molding operation based on the registered clamping force or the abnormality judgment threshold and the clamping force measured during clamping.

2. An injection molding apparatus as described in claim 1, characterized in that the molding operation device is capable of registering in advance at least one of the clamping force and the abnormality judgment threshold together with information about the mold, the molding operation device is capable of selecting a mold to be clamped from the pre-registered molds before clamping the mold, and the clamping state judgment unit judges abnormalities in the clamping force based on the clamping force or the abnormality judgment threshold stored in correspondence with the selected mold.

3. An injection molding apparatus as described in claim 2, wherein the controller is provided with a clamping force display unit, and the clamping force display unit, when registering at least one of the clamping force and the abnormality judgment threshold, causes the magnetic clamp device to clamp the mold and displays the measured value of the clamping force measured at this time.

4. An injection molding apparatus as described in claim 2, characterized in that the molding operation device is capable of registering in advance at least one of the clamping force and the abnormality judgment threshold value, and molding conditions together with mold information, and the molding conditions include at least one of the resin temperature, mold temperature, and filling pressure.

5. An injection molding apparatus according to claim 1, wherein the controller is provided with an alarm section which issues an alarm when the clamping state determination section determines that there is an abnormality in the clamping force.

6. An injection molding apparatus as defined in claim 5, wherein the magnetic clamp device clamps the mold on both the fixed side and the movable side, the clamping force abnormality determination unit determines whether there is an abnormality in the clamping force on both the fixed side and the movable side, and when the clamping force abnormality determination unit determines that there is an abnormality in the clamping force on only one of the fixed side and the movable side, the alarm generated by the alarm unit includes information indicating whether there is an abnormality in the clamping force on the fixed side or the movable side.

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