Injection molding machine and setting method of mold protection set value

Abstract

To easily set a set value used for mold protection when closing a mold.SOLUTION: An injection molding machine comprises: a fixed die 21 to which a fixed mold 26 is attached; a movable die 22 to which a movable mold 27 is attached and which is disposed in a direction in which the movable mold 27 faces the fixed mold 26 attached to the fixed die 21; a mold opening / closing mechanism 40 which opens and closes the movable mold 27 and the fixed mold 26 and clamps the molds; and a control device 100 which controls the mold opening / closing mechanism 40. The control device 100 calculates a mold protection set value V which is a set value for an operation of the movable die 22 to protect the mold 25 when closing the mold at a low-pressure mold clamping force that is set as a mold clamping force lower than the maximum mold clamping force by the mold opening / closing mechanism 40 based on thrust position relation data F that indicates the relation between movable die thrust T, which is force to move the movable die 22 toward a side where the fixed die 21 is located by the mold opening / closing mechanism 40, and a movable die position M, which is a position in a moving direction of the movable die 22.SELECTED DRAWING: Figure 10

Description

[Technical field]

[0001] The present invention relates to an injection molding machine and a method for setting mold protection settings. [Background technology]

[0002] An injection molding machine that performs molding by injecting molten resin in a heated barrel into a mold has a mold clamping device that applies a mold clamping force to the molds, and performs molding in the molds with the mold clamping device applying a mold clamping force to a pair of molds. The mold clamping device has a fixed die and a movable die that are arranged side by side with a gap between them. A mold is arranged on each of the fixed die and the movable die, and the mold clamping device can apply a mold clamping force to the molds arranged on each of the fixed die and the movable die by changing the distance between the fixed die and the movable die.

[0003] In an injection molding machine, molding is performed while applying a clamping force to the mold in this way, so in order to perform appropriate molding, it is important to control the movable die according to its position and manage the clamping force. For example, in a method for setting a reference value for a mold closing position described in Patent Document 1, an automatic mold thickness adjustment process is performed, and then an automatic closing position detection process is performed, and the mold closing position detected by the automatic closing position detection process is set as a reference value, thereby reliably setting a regular reference value, stably setting an accurate mold clamping force, and improving work efficiency.

[0004] Furthermore, when closing the mold, if the movable mold is brought into contact with the fixed mold at a high speed, the mold may be damaged by the impact of the contact, so in conventional injection molding machines, in order to protect the mold, a so-called low-pressure mold clamping force is controlled by bringing the movable mold into contact with the fixed mold while approaching it at a low speed. For example, in the method of controlling a mold clamping device described in Patent Document 2, the mold is closed with a low-pressure mold clamping force, and when the movable mold approaches the fixed mold, a clamping force greater than the low-pressure mold clamping force is applied to the movable mold to clamp it, and a set value for the low-pressure mold clamping force is obtained based on the correlation between the value of the low-pressure mold clamping force and the position where the movable mold stops, making it possible to easily set the low-pressure mold clamping force. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2006-15551 A [Patent Document 2] JP 2008-49674 A Summary of the Invention [Problem to be solved by the invention]

[0006] When molding a molded product using an injection molding machine, various settings are made regarding the operation of the injection molding machine. For example, the die advance limit confirmation position and the movable die thrust limit are examples of settings for protecting the mold during mold closing. The die advance limit confirmation position is a position that is set relative to the position of the movable die that performs the mold closing operation with low-pressure mold clamping force, and is set as a position for detecting abnormalities such as whether or not a foreign object is caught in the mold during mold closing. The die advance limit confirmation position is set at a position where the movable die is slightly retreated in the direction away from the fixed die from the position of the movable die when the mold is closed with the low-pressure mold clamping force at its maximum.

[0007] The moving die thrust limit is set as the upper limit of the thrust of the moving die when closing the mold with a low pressure mold clamping force. In other words, when moving the moving die during mold closing, various frictional resistances are generated against the movement, so the thrust of the moving die needs to be large enough to overcome the frictional resistance and bring the molds into contact with each other, but if the thrust of the moving die is made too large, when a foreign object is sandwiched between the molds, the foreign object may be crushed by the mold, which may result in damage to the molds. For this reason, the thrust of the moving die during mold closing needs to be large enough to reliably bring the molds into contact with each other and not to damage the molds even when a foreign object is sandwiched between the molds, and the moving die thrust limit is set as the upper limit of the thrust for the moving die to realize such an operation.

[0008] These die advance limit confirmation positions and movable die thrust limits are different for each mold, and therefore are set each time the mold is replaced. However, the die advance limit confirmation position and movable die thrust limit need to be set by closing the mold while observing the state of the mold, and therefore the time required for setting tends to be long. In addition, since the die advance limit confirmation position and movable die thrust limit are set while observing the state of the mold, they are highly dependent on the experience of the operator, and there is a risk that the set values ​​will vary depending on the person who sets them. For this reason, there is room for improvement in the setting of the set values ​​used to protect the mold when closing the mold in the injection molding machine.

[0009] The present invention has been made in consideration of the above, and aims to provide an injection molding machine and a method for setting mold protection setting values ​​that can easily set setting values ​​used for protecting the mold when closing the mold. [Means for solving the problem]

[0010] In order to solve the above-mentioned problems and achieve the object, the injection molding machine of the present invention comprises a fixed die to which the fixed die is attached, a movable die to which the movable die is attached and which is arranged in a direction in which the movable die faces the fixed die attached to the fixed die, a mold opening and closing mechanism that opens, closes, and clamps the movable die attached to the movable die and the fixed die by moving the movable die in a direction in which the distance between the movable die and the fixed die changes by a driving force generated by a clamping motor which is a power source, and a control device that controls the mold opening and closing mechanism, and the control device calculates a mold protection setting value which is a setting value for the operation of the movable die to protect the mold when the mold is closed at a low-pressure mold clamping force which is set as a mold clamping force lower than the maximum mold clamping force by the mold opening and closing mechanism, based on thrust position relationship data which indicates the relationship between a movable die thrust, which is a force that moves the movable die by the mold opening and closing mechanism to the side where the fixed die is located, and a movable die position, which is the position in the movement direction of the movable die.

[0011] In order to solve the above-mentioned problems and achieve the object, a method for setting a mold protection setting value according to the present invention includes a fixed die to which the fixed die is attached, a movable die to which the movable die is attached and which is disposed in a direction in which the movable die faces the fixed die attached to the fixed die, and a mold opening and closing device for opening and closing the movable die attached to the movable die and the fixed die and clamping the mold by moving the movable die in a direction in which the distance between the movable die and the fixed die changes by a driving force generated by a clamping motor which is a power source. A method for setting a mold protection setting value, which is a setting value for the operation of the movable die to protect the mold when closing the mold at a low-pressure mold clamping force that is set as a mold clamping force lower than the maximum mold clamping force by the mold opening and closing mechanism in an injection molding machine having a mold opening and closing mechanism, includes a step of obtaining thrust position relationship data indicating the relationship between a movable die thrust, which is a force that moves the movable die to the side where the fixed die is located by the mold opening and closing mechanism, and a movable die position, which is the position of the movable die in the movement direction, and a step of calculating the mold protection setting value based on the thrust position relationship data. Effect of the Invention

[0012] The injection molding machine and the method for setting a mold protection setting value according to the present invention have the advantage that the setting value used for protecting the mold when the mold is closed can be easily set. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a side view of an injection molding machine according to an embodiment. [Diagram 2] FIG. 2 is a side view of the mold clamping device shown in FIG. [Diagram 3] FIG. 3 is a view taken along the line AA in FIG. [Figure 4] FIG. 4 is an explanatory diagram of an injection molding cycle performed by an injection molding machine. [Diagram 5] FIG. 5 is an explanatory diagram of the operation of the mold clamping device in the mold clamping process. [Figure 6] FIG. 6 is an explanatory diagram showing the relationship between the moving die thrust and the moving die position when the mold is closed and when the mold is opened. [Figure 7] FIG. 7 is a detailed view of the portion B in FIG. 6, and is an explanatory view showing the relationship between the thrust force of the moving die and the position of the moving die during the pressing operation. [Figure 8] FIG. 8 is a detailed view of a portion C in FIG. 6, and is an explanatory view showing the relationship between the thrust force of the moving die and the position of the moving die during the depressurization operation. [Figure 9] FIG. 9 is a flow chart showing a processing procedure for setting the die advance limit confirmation position based on the depressurization operation. [Figure 10] FIG. 10 is an explanatory diagram for a case where the die advance limit confirmation position is set using thrust-position relationship data during depressurization operation. [Figure 11] FIG. 11 is a flow diagram showing a processing procedure for setting the moving die thrust limit based on the depressurization operation. [Figure 12] FIG. 12 is an explanatory diagram for setting the moving die thrust limit using thrust position relationship data during depressurization operation. [Figure 13] FIG. 13 is a flowchart showing a process for setting the die advance limit confirmation position based on the pressing operation. [Figure 14] FIG. 14 is an explanatory diagram for a case where the die advance limit confirmation position is set using thrust-position relationship data during the pressing operation. [Figure 15] FIG. 15 is a flow diagram showing a processing procedure when the moving die thrust limit is set based on the pressing operation. [Figure 16] FIG. 16 is an explanatory diagram for setting a moving die thrust limit using thrust position relationship data during a pressing operation. [Figure 17] FIG. 17 is a flow chart showing a processing procedure for setting the die advance limit confirmation position by using a pressing operation and a pressure release operation in combination. [Figure 18] FIG. 18 is a flow diagram showing a processing procedure in the case where the moving die thrust limit is set by using both the pressing operation and the depressurizing operation. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of an injection molding machine and a method for setting a mold protection setting value according to the present disclosure will be described in detail with reference to the drawings. Note that the present invention is not limited to this embodiment. In addition, the components in the following embodiments include those that are replaceable and easily conceivable by a person skilled in the art, or those that are substantially the same.

[0015] [Embodiment] 1 is a side view of an injection molding machine 1 according to an embodiment. In the following description, the up-down direction of the injection molding machine 1 in normal use is described as the up-down direction Z of the injection molding machine 1, the upper side of the injection molding machine 1 in normal use is described as the upper side of the injection molding machine 1, and the lower side of the injection molding machine 1 in normal use is described as the lower side of the injection molding machine 1. In the following description, the longitudinal direction Y of the injection molding machine 1 is also described as the longitudinal direction Y of each part having the injection molding machine 1, and the direction perpendicular to both the up-down direction Z and the longitudinal direction Y of the injection molding machine 1 is described as the width direction X of the injection molding machine 1.

[0016] <Injection molding machine 1> The injection molding machine 1 according to this embodiment includes a fixed frame 5, an injection unit 10 arranged on the frame 5, and a mold clamping unit 20 arranged on the frame 5. The injection unit 10 and the mold clamping unit 20 are arranged side by side in the longitudinal direction Y on the frame 5, and the mold clamping unit 20 is covered by a cover 6 on the frame 5.

[0017] <Injection device 10> The injection device 10 has an injection cylinder 11, a screw 13, and a hopper 14. The injection cylinder 11 is formed in a substantially cylindrical shape, and is disposed so that the axial direction is oriented along the longitudinal direction Y. A nozzle 12 for injecting the resin material molten in the injection cylinder 11 is disposed at the end on the side where the mold clamping device 20 is located in the longitudinal direction Y. More specifically, the injection cylinder 11 is provided with a heater (not shown) such as a band heater, and the temperature of the injection cylinder 11 can be increased by the heater. This allows the injection cylinder 11 to heat and melt the resin material inside the injection cylinder 11, and turn the resin material into molten resin, which is a plasticizing material. The nozzle 12 is a part that injects the molten resin material from inside the injection cylinder 11 to the outside of the injection cylinder 11.

[0018] The screw 13 is disposed inside the injection cylinder 11 and has a helical shape with its axial direction aligned with the axial direction of the injection cylinder 11, i.e., the screw 13 has a helical groove on its outer circumferential surface. In this way, the screw 13 having a helical groove is rotatable around its axial center within the injection cylinder 11. The screw 13 is disposed within the injection cylinder 11 such that the central axis of the cylinder, which is the shape of the injection cylinder 11, and the rotation axis of the screw 13 are substantially aligned, and the screw 13 is disposed so as to be movable in the axial direction of the injection cylinder 11. The screw 13 rotatably disposed within the injection cylinder 11 is capable of kneading the molten resin by rotating within the injection cylinder 11, and therefore the injection cylinder 11 is a cylinder capable of kneading the molten resin inside.

[0019] A hopper 14 is disposed near the opposite side of the injection cylinder 11 to the side where the nozzle 12 is located in the longitudinal direction Y. The hopper 14 communicates with the inside of the injection cylinder 11 and is capable of supplying pellets (not shown) which are a resin material that becomes raw resin, to the injection cylinder 11.

[0020] In the injection device 10 configured as above, the screw 13 is rotated by a metering motor (not shown), and the resin material is melted and kneaded in the injection cylinder 11 while the molten resin is accumulated in a portion of the injection cylinder 11 close to the nozzle 12, thereby performing metering. The molten resin accumulated in the injection cylinder 11 is injected from the nozzle 12 by moving the screw 13 to the side where the nozzle 12 is located by an injection motor (not shown), a ball screw, and a nut (not shown). In this way, the injection device 10 injects the resin material molten in the injection cylinder 11 into the mold 25 arranged in the mold clamping device 20, and fills the cavity of the mold 25 with the molten resin.

[0021] <Mold clamping device 20> Fig. 2 is a side view of the mold clamping device 20 shown in Fig. 1. Fig. 2 is an explanatory diagram of the mold clamping device 20 in a state in which the cover 6 is removed from the injection molding machine 1 shown in Fig. 1. In the explanation of the mold clamping device 20, when each element of the mold clamping device 20 "advances", it means that it moves in the direction in which the injection device 10 is located relative to the mold clamping device 20 in the longitudinal direction Y (to the right in Fig. 2). When each element of the mold clamping device 20 "retreats", it means that it moves in the opposite direction (to the left in Fig. 2) to the direction in which the injection device 10 is located relative to the mold clamping device 20 in the longitudinal direction Y.

[0022] The mold clamping device 20 includes, for example, a fixed die 21 fixed to a frame 5, a movable die 22 arranged opposite the fixed die 21 and capable of moving toward and away from the fixed die 21, and a link housing 30 arranged movably on the frame 5.

[0023] The fixed die 21 and the moving die 22 are fitted with a mold 25 used for molding the resin material injected from the injection device 10. The fixed die 26 of the pair of molds 25 consisting of a fixed die 26 and a moving die 27 is fitted to the fixed die 21, and the moving die 27 of the pair of molds 25 is fitted to the moving die 22. The moving die 22 to which the moving die 27 is fitted is disposed in a direction in which the moving die 27 faces the fixed die 26 attached to the fixed die 21. In detail, the moving die 22 is disposed on the opposite side of the fixed die 21 from the side where the injection device 10 is disposed in the longitudinal direction Y, and the moving die 22 and the fixed die 21 are disposed in a direction in which the moving die 27 attached to the moving die 22 and the fixed die 26 attached to the fixed die 21 face each other in the longitudinal direction Y.

[0024] The link housing 30 is disposed on the opposite side of the movable die 22 from the side on which the fixed die 21 is disposed in the longitudinal direction Y. That is, the fixed die 21, the movable die 22, and the link housing 30 are disposed in this order in the longitudinal direction Y from the side on which the injection device 10 is located.

[0025] A plurality of tie bars 70 are arranged between the fixed die 21 and the link housing 30, and for example, four tie bars 70 are arranged. The tie bar 70 is formed in a rod shape extending in the longitudinal direction Y, one end side is fixed to the fixed die 21, and the other end side is connected to the link housing 30. As a result, the fixed die 21 and the link housing 30 are connected via the tie bar 70. On the other hand, the tie bar 70 is not connected to the movable die 22 arranged between the fixed die 21 and the link housing 30, and the tie bar 70 penetrates the movable die 22 in the longitudinal direction Y. When the mold 25 is clamped to perform mold clamping, the tie bar 70 is stretched in the longitudinal direction Y by the mold opening and closing mechanism 40 described later, and a mold clamping force can be generated by the reaction force.

[0026] A tie bar sensor 75 is attached to each tie bar 70. The tie bar sensor 75 is, for example, a strain sensor, and is capable of detecting the elongation of the tie bar 70 in the extending direction, i.e., the elongation of the tie bar 70 in the longitudinal direction Y. The tie bar sensor 75 that detects the elongation of the tie bar 70 is capable of detecting the magnitude of the clamping force when the mold 25 is clamped by the mold opening and closing mechanism 40, by detecting the elongation of the tie bar 70. Note that the tie bar sensor 75 does not have to be provided on all four tie bars 70, and the tie bar sensor 75 may be provided on only one of the four tie bars 70, for example.

[0027] The mold opening and closing mechanism 40 has a toggle link 41 and a drive unit 50. The toggle link 41 is connected to the link housing 30 and the movable die 22 to change the distance between the link housing 30 and the movable die 22 in the longitudinal direction Y, and the drive unit 50 is capable of operating the toggle link 41.

[0028] The driving device 50 has a ball screw 51, a crosshead 52, a nut 53, and a clamping motor 60 (see FIG. 3) which is a power source. The ball screw 51 penetrates the link housing 30 in the longitudinal direction Y, and is disposed so as to extend in the longitudinal direction Y mainly from the link housing 30 to the side where the movable die 22 is located.

[0029] The nut 53 is attached to the crosshead 52, and the crosshead 52 is disposed together with the nut 53 between the link housing 30 and the movable die 22. The nut 53 attached to the crosshead 52 is screwed into the ball screw 51 between the link housing 30 and the movable die 22. This allows the crosshead 52 to move in the longitudinal direction Y together with the nut 53 screwed into the ball screw 51 as the ball screw 51 rotates.

[0030] 3 is a view taken along the line AA in FIG. 2. The clamping motor 60 is attached to the link housing 30, and in this embodiment, is attached to the side of the link housing 30 in the width direction X. The clamping motor 60 is, for example, a servo motor, and can drive the ball screw 51 via a first pulley 61, a timing belt 63, and a second pulley 62 in this order. In detail, the first pulley 61 is attached to the output shaft of the clamping motor 60. The second pulley 62 is attached to the end of the ball screw 51 on the opposite side to the side where the moving die 22 is located with respect to the link housing 30. The timing belt 63 is wound around the first pulley 61 and the second pulley 62, and transmits the driving force generated by the clamping motor 60 and transmitted from the first pulley 61 to the timing belt 63 to the ball screw 51 via the second pulley 62.

[0031] The ball screw 51 rotates by a driving force generated by a mold clamping motor 60 and transmitted to the ball screw 51 via a first pulley 61, a timing belt 63, and a second pulley 62. A nut 53 screwed into the ball screw 51 moves linearly in the longitudinal direction Y along the ball screw 51, and a crosshead 52 formed integrally with the nut 53 moves linearly in the longitudinal direction Y along the ball screw 51 together with the nut 53.

[0032] The link housing 30 and the movable die 22 are connected to each other by a toggle link 41 of the die opening / closing mechanism 40. The toggle link 41 has a crosshead side link 42, a link housing side link 43, and a movable die side link 44. Of these, the link housing side link 43 has an end portion located on the link housing 30 side in the longitudinal direction Y rotatably connected to the link housing 30, and an opposite end portion rotatably connected to the movable die side link 44. The movable die side link 44 has an end portion rotatably connected to the movable die 22 via a toggle link connecting portion 45, the opposite end portion to the end portion connected to the link housing side link 43 in the longitudinal direction Y.

[0033] Therefore, by rotating each connecting portion of the link housing side link 43 and the movable die side link 44, the distance in the longitudinal direction Y between the end of the link housing side link 43 connected to the link housing 30 and the end of the movable die side link 44 connected to the moving die 22 can be changed. As a result, the link housing side link 43 and the movable die side link 44 can change the distance in the longitudinal direction Y between the link housing 30 and the moving die 22.

[0034] Moreover, one end of the crosshead side link 42 is rotatably connected to the crosshead 52, and the other end is rotatably connected to the link housing side link 43. Therefore, the crosshead side link 42 can transmit the movement of the crosshead 52 moving in the longitudinal direction Y to the link housing side link 43. As a result, the crosshead side link 42 can operate the link housing side link 43 and the movable die side link 44.

[0035] The toggle links 41 thus configured are disposed on both sides in the vertical direction Z with respect to the crosshead 52. That is, the toggle links 41 are disposed on both the upper and lower sides in the vertical direction Z with respect to the crosshead 52, and the link housing 30 and the moving die 22 are connected via the upper and lower toggle links 41.

[0036] The toggle link 41 has a crosshead side link 42 connected to the crosshead 52, and the crosshead 52 is arranged to be movable in the longitudinal direction Y along the ball screw 51 by a driving force generated by the mold clamping motor 60. Therefore, the movement of the crosshead 52, which moves in the longitudinal direction Y by the driving force generated by the mold clamping motor 60, is transmitted to the crosshead side link 42, and the link housing side link 43 and the movable die side link 44, whose respective connecting portions are rotatably connected, are operated. The drive unit 50 can operate the toggle link 41 by the driving force generated by the mold clamping motor 60 in this manner.

[0037] The mold opening and closing mechanism 40 can move the moving die 22 in the longitudinal direction Y with respect to the link housing 30 by operating the toggle link 41 with the drive device 50. This allows the mold opening and closing mechanism 40 to move the moving die 27 attached to the moving die 22 in the longitudinal direction Y relative to the fixed die 26 attached to the fixed die 21, and can open and close the moving die 27 and the fixed die 26 and clamp the mold. That is, the mold opening and closing mechanism 40 opens and closes the moving die 27 and the fixed die 26 and clamps the mold by moving the moving die 22 in a direction in which the distance between the moving die 22 and the fixed die 21 changes by the driving force generated by the clamping motor 60.

[0038] When the fixed die 26 and the movable die 27 are closed or clamped by the die opening / closing mechanism 40, the crosshead 52 is advanced by the die clamping motor 60, and the die opening / closing mechanism 40 is extended. That is, by driving the die clamping motor 60, the ball screw 51 is rotated in a predetermined direction via the timing belt 63, and the nut 53 screwed into the ball screw 51 and the crosshead 52 provided integrally with the nut 53 are advanced in the direction in which the fixed die 21 is located in the longitudinal direction Y. At this time, the upper link housing side link 43 and the movable die side link 44 open upward, and the lower link housing side link 43 and the movable die side link 44 open downward, and the movement of the crosshead 52 is transmitted to the movable die 22 via the toggle link 41. As a result, the fixed die 26 and the movable die 27 are closed or clamped.

[0039] On the other hand, when the fixed die 26 and the movable die 27 are opened, the crosshead 52 is retracted by the clamping motor 60, and the link housing side link 43 and the movable die side link 44 are bent. That is, by driving the clamping motor 60, the ball screw 51 is rotated in the opposite direction to that during mold closing via the timing belt 63, and the nut 53 and the crosshead 52 are retracted in the direction in which the link housing 30 is located in the longitudinal direction Y. In this way, by retracting the nut 53 in the direction in which the link housing 30 is located, the upper link housing side link 43 and the movable die side link 44 close downward, and the lower link housing side link 43 and the movable die side link 44 close upward, and the movement of the crosshead 52 is transmitted to the movable die 22 via the toggle link 41. As a result, the fixed die 26 and the movable die 27 are opened.

[0040] In this manner, in this embodiment, when the mold closing or clamping is completed, the link housing side link 43 and the movable die side link 44 are substantially linear, and when the mold is opened, the link housing side link 43 and the movable die side link 44 bend toward the side where the axis of the ball screw 51 is located. In other words, when the mold is opened, the link housing side link 43 and the movable die side link 44 are structured to bend so as to be rolled inward in the vertical direction Z.

[0041] A first linear guide 90, which is a guide mechanism for guiding the moving die 22 in the longitudinal direction Y, is provided on the frame 5. The first linear guide 90 has a first guide rail 91 arranged on the frame 5 and extending in the longitudinal direction Y, and a first block 92 attached to the moving die 22 and movable along the first guide rail 91 while sliding relative to the first guide rail 91. The first guide rail 91 is arranged at two positions near both ends of the moving die 22 in the width direction X, and is formed extending to both sides of the moving die 22 in the longitudinal direction Y. The first block 92 is arranged at two positions near both ends of the moving die 22 in the width direction X, and the two first blocks 92 are attached to the moving die 22 with the interval in the width direction X being substantially the same as the interval of the first guide rail 91.

[0042] Further, a second linear guide 95, which is a guide mechanism for guiding the link housing 30 in the longitudinal direction Y, is provided on the frame 5. The second linear guide 95 has a second guide rail 96 arranged on the frame 5 and extending in the longitudinal direction Y, and a second block 97 attached to the link housing 30 and movable along the second guide rail 96 while sliding relative to the second guide rail 96. The second guide rail 96 is arranged at two positions near both ends of the link housing 30 in the width direction X, and is formed extending to both sides of the link housing 30 in the longitudinal direction Y. The second block 97 is arranged at two positions near both ends of the link housing 30 in the width direction X, and the two second blocks 97 are attached to the link housing 30 with the interval in the width direction X being substantially the same as the interval of the second guide rail 96.

[0043] The first guide rail 91 of the first linear guide 90 and the second guide rail 96 of the second linear guide 95 may be formed continuously to constitute the same guide rail.

[0044] The four tie bars 70 connecting the fixed die 21 and the link housing 30 are connected to the fixed die 21 and the link housing 30 at two locations near both ends in the width direction X and two locations near both ends in the up-down direction Z (see FIG. 3). That is, the four tie bars 70 are connected to the four corners of the fixed die 21 and the link housing 30 near both ends in the width direction X and near both ends in the up-down direction Z.

[0045] A threaded portion (not shown) is formed on the outer circumferential surface of the tie bar 70 near the end connected to the link housing 30. The tie bar 70 and the link housing 30 are connected by a tie bar nut 81 that screws into the threaded portion of the tie bar 70 and is disposed on the link housing 30. The tie bar nut 81 is disposed in the thickness direction of the link housing 30, i.e., on the opposite side to the side where the fixed die 21 and the movable die 22 are disposed in the longitudinal direction Y, and is attached to be rotatable relative to the link housing 30.

[0046] A through hole (not shown) into which the tie bar 70 is inserted is formed in the link housing 30. The through hole has an inner diameter approximately equal to the outer diameter of the tie bar 70, and is formed penetrating the link housing 30 in the thickness direction of the link housing 30, i.e., in the longitudinal direction Y. The tie bar 70 is connected to the link housing 30 by being inserted into the through hole thus formed in the link housing 30.

[0047] The tie bar nut 81 is disposed in a portion of a through hole formed in the link housing 30 that opens to a surface opposite to the side on which the fixed die 21 and the movable die 22 are disposed in the longitudinal direction Y, and is screwed into the threaded portion of the tie bar 70. Therefore, the tie bar nut 81 can move relative to the tie bar 70 in the longitudinal direction Y by rotating the tie bar nut 81 in the helical direction of the threaded portion of the tie bar 70.

[0048] Furthermore, the tie bar nut 81 is disposed in the link housing 30, and the link housing 30 is disposed on the frame 5 via the second linear guide 95. For this reason, when the tie bar nut 81 is rotated, the tie bar nut 81 moves relative to the tie bar 70 in the longitudinal direction Y, and the link housing 30 on which the tie bar nut 81 is disposed can also move in the longitudinal direction Y while being guided by the second linear guide 95.

[0049] In this way, the tie bar nut 81, which can move the link housing 30 in the longitudinal direction Y by rotating relative to the tie bar 70, constitutes a mold thickness adjustment mechanism 80. In addition to the tie bar nut 81, the mold thickness adjustment mechanism 80 has a mold thickness adjustment motor 84, a drive gear 85, an annular gear 86, and a tie bar nut gear 87 (see Figures 2 and 3).

[0050] Of these, the tie bar nut gears 87 are attached to four tie bar nuts 81 which are screwed onto the four tie bars 70, respectively. The ring gear 86 is arranged to mesh with the four tie bar nut gears 87. The drive gear 85 is attached to the output shaft of the mold thickness adjustment motor 84, and arranged to mesh with the ring gear 86 to drive the ring gear 86. The mold thickness adjustment motor 84 is, for example, a servo motor, and is provided as a power source for the mold thickness adjustment mechanism 80. The mold thickness adjustment motor 84 is attached to the link housing 30, and in this embodiment, is attached to a side surface of the link housing 30 in the width direction X.

[0051] In the mold thickness adjustment mechanism 80 configured as above, the drive gear 85 rotates when the mold thickness adjustment motor 84 is driven. The rotating drive gear 85 rotates the four tie bar nut gears 87 in the same direction via the annular gear 86, and rotates the four tie bar nuts 81 in the same direction. When the tie bar nut 81 rotates, the tie bar nut 81 moves together with the link housing 30 relative to the tie bar 70 in the longitudinal direction Y, so when the tie bar nut 81 rotates, the mold thickness adjustment mechanism 80 having the tie bar nut 81 moves integrally with the link housing 30 relative to the tie bar 70 in the longitudinal direction Y.

[0052] Here, the link housing 30 is connected to the movable die 22 via a toggle link 41 of the mold opening and closing mechanism 40. In addition, the movable die 22 is disposed on the frame 5 via a first linear guide 90. For this reason, when the link housing 30 is moved in the longitudinal direction Y by the mold thickness adjustment mechanism 80, the movable die 22 connected to the link housing 30 via the toggle link 41 also moves in the longitudinal direction Y together with the link housing 30 while being guided by the first linear guide 90.

[0053] Since the movable die 22 is attached with the movable mold 27, when the movable die 22 moves in the longitudinal direction Y, the distance between the movable mold 27 attached to the movable die 22 and the fixed mold 26 attached to the fixed die 21 changes. This allows the mold thickness adjustment mechanism 80 to adjust the relative positions of the movable mold 27 and the fixed mold 26. This allows, for example, when the mold 25 is replaced, to appropriately adjust the distance between the fixed mold 26 and the movable mold 27 in the longitudinal direction Y by moving the link housing 30 and the movable mold 27 in the longitudinal direction Y by the mold thickness adjustment mechanism 80 in accordance with the thickness of the mold 25 in the longitudinal direction Y.

[0054] The injection molding machine 1 also has a control device 100 that performs various controls of the injection molding machine 1. The control device 100 has a CPU (Central Processing Unit) that performs arithmetic processing, and a RAM (Random Access Memory) and a ROM (Read Only Memory) that function as memories for storing various information. All or part of the functions of the control device 100 are realized by loading an application program held in the ROM into the RAM and executing it on the CPU, thereby reading and writing data from and to the RAM and ROM.

[0055] A display unit 101 that displays various information about the injection molding machine 1 and an input unit 102 that an operator uses to perform input operations on the injection molding machine 1 are connected to the control device 100. The display unit 101 connected to the control device 100 displays information transmitted from the control device 100, and the input unit 102 transmits the input information to the control device 100.

[0056] The injection molding machine 1 is equipped with various sensors that detect various states during operation of the injection molding machine 1, and these sensors are connected to the control device 100. The control device 100 controls the operation of the injection molding machine 1 by controlling the actuators of the injection molding machine 1 based on the detection results from these sensors.

[0057] For example, a heater (not shown) disposed in the injection cylinder 11 of the injection unit 10, a mold clamping motor 60 of the mold opening and closing mechanism 40, and a mold thickness adjustment motor 84 of the mold thickness adjustment mechanism 80 are connected to the control device 100 and are operated by control signals from the control device 100. In addition, the mold clamping motor 60 of the mold opening and closing mechanism 40 and the mold thickness adjustment motor 84 of the mold thickness adjustment mechanism 80 are equipped with encoders (not shown), which are also connected to the control device 100 and can transmit detection results to the control device 100. In this way, the control device 100 can control the injection unit 10, the mold opening and closing mechanism 40 of the mold clamping unit 20, and the mold thickness adjustment mechanism 80.

[0058] <Action of injection molding machine 1> The injection molding machine 1 according to this embodiment includes the above-mentioned configuration, and its operation will be described below. Note that the control of the injection molding machine 1 described below is performed by the control device 100.

[0059] FIG. 4 is an explanatory diagram of an injection molding cycle by the injection molding machine 1. First, the flow of the entire injection molding process will be briefly described. When performing injection molding, as shown in FIG. 4, the injection molding machine 1 according to this embodiment performs an injection molding cycle S100. The injection molding machine 1 performs injection molding by controlling actuators of the injection molding machine 1 with the control device 100 while acquiring the operating state of each part of the injection molding machine 1 from the detection results of sensors. The injection molding cycle S100 when performing injection molding with the injection molding machine 1 specifically includes a mold clamping process S101, an injection process S102, a weighing and cooling process S103, a mold opening process S104, and a product removal process S105, and a large number of molded products are produced by repeating these processes in order.

[0060] Next, the action of the mold clamping device 20 in the mold clamping step S101 will be described. Fig. 5 is an explanatory diagram of the operation of the mold clamping device 20 in the mold clamping step. At the start of the mold clamping step S101, as shown in Fig. 5(a), the mold clamping device 20 is in a mold open state with the movable mold 27 separated from the fixed mold 26.

[0061] In the mold clamping step S101, the mold clamping device 20 closes and clamps the mold 25 from the mold open state. When closing the mold 25, the control device 100 drives the mold clamping motor 60 of the mold opening and closing mechanism 40 of the mold clamping device 20 to advance the crosshead 52. This causes the link housing side link 43 and the movable die side link 44 of the toggle link 41 to extend. That is, by driving the mold clamping motor 60, the ball screw 51 rotates in a predetermined direction via the timing belt 63, and the nut 53 and the crosshead 52 screwed into the ball screw 51 advance in the longitudinal direction Y toward the position of the fixed die 21.

[0062] When the crosshead 52 moves in the longitudinal direction Y, the movement of the crosshead 52 is transmitted to the link housing side link 43 via the crosshead side link 42 of the toggle link 41. As a result, the upper toggle link 41 operates in a direction in which the link housing side link 43 and the movable die side link 44 open upward in the vertical direction Z, and the lower toggle link 41 operates in a direction in which the link housing side link 43 and the movable die side link 44 open downward in the vertical direction Z.

[0063] Since the end of the movable die side link 44 opposite to the end connected to the link housing side link 43 is connected to the movable die 22, when the link housing side link 43 and the movable die side link 44 move in the opening direction, the movable die 22 advances along with the movement of the movable die side link 44. When closing the mold, the movement of the crosshead 52 in the longitudinal direction Y is transmitted to the movable die 22 via the toggle link 41 in this manner, and the movable die 22 advances in the longitudinal direction Y to the side where the fixed die 21 is located.

[0064] A movable mold 27 is attached to the surface of the movable die 22 on the side where the fixed die 21 is located. Meanwhile, a fixed mold 26 is attached to the surface of the fixed die 21 on the side where the movable die 22 is located. Therefore, when the movable die 22 advances to the side where the fixed die 21 is located in the longitudinal direction Y, the movable mold 27 attached to the movable die 22 comes into contact with the fixed mold 26 attached to the fixed die 21. In this way, the movable mold 27 attached to the movable die 22 comes into contact with the fixed mold 26 attached to the fixed die 21, whereby the fixed mold 26 and the movable mold 27 are closed (FIG. 5(b)).

[0065] When the fixed mold 26 and the movable mold 27 come into contact with each other and close, the tie bar 70 extends very slightly in the longitudinal direction Y. The extension of the tie bar 70 is detected by a tie bar sensor 75 attached to the tie bar 70 and transmitted to the control device 100. In this way, the control device 100 detects that the fixed mold 26 and the movable mold 27 have been closed.

[0066] When the fixed mold 26 and the movable mold 27 are closed, the control device 100 further drives the clamping motor 60 of the mold opening and closing mechanism 40 of the clamping device 20 to further advance the crosshead 52. As a result, the movable mold 27 is pressed against the fixed mold 26, and the fixed mold 26 and the movable mold 27 are clamped together (FIG. 5(c)).

[0067] At this time, the tie bar 70 further extends slightly in the longitudinal direction Y. In other words, when the mold clamping motor 60 is driven to extend the link housing side link 43 and the movable die side link 44 of the toggle link 41 to press the movable die 27 against the fixed die 26, the extension of the toggle link 41 increases the distance between the link housing 30 and the movable die 22, so that the link housing 30 moves slightly in the longitudinal direction Y to the side opposite to the side where the fixed die 21 is located.

[0068] Since the end of the tie bar 70 opposite the end fixed to the fixed die 21 is connected to the link housing 30 by the tie bar nut 81, when the link housing 30 moves in the longitudinal direction Y to the side opposite to the side where the fixed die 21 is located, the tie bar 70 extends slightly in the longitudinal direction Y in conjunction with the movement of the link housing 30. As the tie bar 70 extends, the link housing 30 moves in the longitudinal direction Y to the side opposite to the side where the fixed die 21 is located while being guided by the second linear guide 95.

[0069] Both ends of the tie bar 70 are connected to the fixed die 21 and the link housing 30, and therefore, when the tie bar 70 expands, a force tending to contract acts on the fixed die 21 and the link housing 30. Since the movable die 22 to which the movable die 27 is attached is connected to the link housing 30 via the toggle link 41, when a force tending to contract of the tie bar 70 acts on the fixed die 21 and the link housing 30, this force acts as a force pressing the movable die 27 attached to the movable die 22 against the fixed die 26 attached to the fixed die 21. As a result, a clamping force, which is a force pressing both the fixed die 26 and the movable die 27 in the longitudinal direction Y, is generated between them.

[0070] Meanwhile, in the mold opening step S104, the mold clamping unit 20 causes the mold opening and closing mechanism 40 to move the crosshead 52 backward in the longitudinal direction Y, and bends the link housing side link 43 and the movable die side link 44, thereby opening the fixed mold 26 and the movable mold 27. That is, the control device 100 drives the mold clamping motor 60 of the mold opening and closing mechanism 40 of the mold clamping unit 20 to rotate the ball screw 51 via the timing belt 63 in the opposite direction to the mold closing time, and moves the nut 53 screwed onto the ball screw 51 and the crosshead 52 backward in the longitudinal direction Y toward the position of the link housing 30.

[0071] When the crosshead 52 retracts, the upper toggle link 41 operates in a direction in which the link housing side link 43 and the movable die side link 44 close downward in the vertical direction Z, and the lower toggle link 41 operates in a direction in which the link housing side link 43 and the movable die side link 44 close upward in the vertical direction Z. As a result, the movable die 22 connected to the link housing 30 via the toggle link 41 retracts to the side where the link housing 30 is located in the longitudinal direction Y, and the fixed die 26 and the movable die 27 are opened.

[0072] When molding a molded product using the injection molding machine 1, in the mold clamping step S101, the fixed mold 26 and the movable mold 27 are clamped by the mold opening and closing mechanism 40 as described above, and in the injection step S102, molten resin, which is a resin material melted by the injection cylinder 11 of the injection device 10, is injected into the cavity formed by the fixed mold 26 and the movable mold 27.

[0073] Thereafter, after the weighing and cooling step S103, the fixed mold 26 and the movable mold 27 are opened as described above by the mold opening and closing mechanism 40 in the mold opening step S104, and the product molded by the mold 25 is removed in the product removal step S105. That is, the injection molding machine 1 is provided with an extrusion mechanism (not shown) having an extrusion member (not shown) that extrudes the molded product attached to the inner surface of the movable mold 27 after molding, and in the product removal step S105, the molded product is removed from the movable mold 27 by the extrusion mechanism.

[0074] Here, in the clamping step S101, the fixed mold 26 and the movable mold 27, which are separated from each other, are brought into contact with each other by bringing the movable mold 27 closer to the fixed mold 26, but if the movable mold 27 is brought into contact with the fixed mold 26 with a large clamping force from a state in which the fixed mold 26 and the movable mold 27 are separated from each other, there is a risk that the mold 25 will be damaged. In other words, if the movable mold 27 is brought into contact with the fixed mold 26 by approaching it at a high speed from a state in which the fixed mold 26 and the movable mold 27 are separated from each other, there is a risk that the mold 25 will be damaged by the impact at the time of contact.

[0075] For this reason, in the injection molding machine 1 according to this embodiment, when closing the mold 25 in the mold clamping step S101, the mold is closed with a low-pressure mold clamping force that is set as a mold clamping force lower than the maximum mold clamping force by the mold opening and closing mechanism 40. That is, when closing the mold 25, the mold opening and closing mechanism 40 reduces the speed of the movable mold 27, brings the movable mold 27 into contact with the fixed mold 26 with a low-pressure mold clamping force, and then presses the movable mold 27 against the fixed mold 26 with a mold clamping force required for molding a molded product. In this way, the injection molding machine 1 closes and clamps the mold while protecting the mold 25.

[0076] In this case, the low-pressure clamping force is preferably set to a force significantly lower than the maximum clamping force by the mold opening and closing mechanism 40, for example, within a range of 1% to 5% of the maximum clamping force. In this embodiment, the low-pressure clamping force is set to 2% of the maximum clamping force by the mold opening and closing mechanism 40.

[0077] <Mold protection setting value V> In the mold clamping step S101, the mold 25 is closed with a low-pressure mold clamping force as described above, and the control device 100 controls the mold closing by the mold opening and closing mechanism 40 based on a mold protection set value V (see Figs. 10, 12, etc.), which is a set value for the operation of the movable die 22 when the mold is closed with a low-pressure mold clamping force. The mold protection set value V is a set value for the operation of the movable die 22 for protecting the mold 25 when the mold is closed with a low-pressure mold clamping force.

[0078] In this embodiment, the mold protection setting value V includes a die forward movement limit confirmation position ML (see Figures 10 and 14) that is set for the position in the movement direction of the movable die 22, and a movable die thrust limit TL (see Figures 12 and 16) that is set for the thrust of the movable die 22 when closing the mold.

[0079] Among these, the die advance limit confirmation position ML is set as a position in the moving direction of the movable die 22, which is slightly separated from the fixed die 21 from the position where the fixed die 26 and the movable die 27 contact with each other under the low pressure mold clamping force. In this case, the position where the fixed die 26 and the movable die 27 contact with each other is a position where the fixed die 26 and the movable die 27 contact with each other under the maximum value of the low pressure mold clamping force or a mold clamping force slightly lower than the maximum value of the low pressure mold clamping force. In addition, the position where the movable die 22 is slightly separated from the fixed die 21 from the position where the fixed die 26 and the movable die 27 contact with each other under the low pressure mold clamping force is, for example, a position where the movable die 27, which contacts the fixed die 26, is moved in the direction away from the fixed die 26 within a range of 0.1 mm to 0.5 mm.

[0080] Here, when the movable die 27 is brought close to the fixed die 26 and the fixed die 26 and the movable die 27 start to come into contact, the entire contact surfaces of both dies 25 do not come into contact with each other at the same time, but rather, due to the mechanical precision of the injection molding machine 1 and the precision of the die 25, they often start to come into contact with each other only at a part of the contact surfaces, such as one-sided contact, depending on the mechanical precision of the injection molding machine 1 and the precision of the die 25. For this reason, the die advance limit confirmation position ML, which is obtained by slightly separating the movable die 22 from the fixed die 21 from the position where the fixed die 26 and the movable die 27 come into contact with each other under low pressure clamping force, is a position which also includes the case where the movable die 27 and the fixed die 26 come into partial contact with each other.

[0081] Further, the moving die thrust limit TL is an upper limit value of the thrust in the moving direction of the moving die 22 when the moving die 22 is moved in a direction approaching the fixed die 21 in order to close the fixed die 26 and the moving die 27 with a low clamping force. The thrust of the moving die 22 in this case is a value calculated from the torque of the clamping motor 60 when the moving die 22 is moved in the longitudinal direction Y by the mold opening and closing mechanism 40. That is, since the mold opening and closing mechanism 40 transmits the driving force generated by the clamping motor 60 to the moving die 22 via the toggle link 41, the thrust of the moving die 22 is a thrust taking into consideration the torque generated by the clamping motor 60 and the operation of the toggle link 41.

[0082] For this reason, the thrust of the moving die 22 has a value that is not proportional to the torque of the clamping motor 60 because the value of the thrust of the moving die 22 relative to the torque of the clamping motor 60 differs depending on the expansion / contraction state of the toggle link 41. The movable die thrust limit TL is thus an upper limit value that is set for the thrust in the moving direction of the moving die 22 calculated from the torque of the clamping motor 60 and the expansion / contraction state of the toggle link 41.

[0083] The mold protection setting value V thus set is used as a judgment value for detecting abnormalities such as whether or not a foreign object has been caught by the mold 25 when the mold is closed.

[0084] That is, when the movable mold 27 and the fixed mold 26 are opened / closed or clamped during molding of the molded product, it is assumed that a foreign object will be caught between the movable mold 27 and the fixed mold 26. For example, if the molded product cannot be properly removed when being removed in the product removal step S105 after the mold opening step S104, the molded product may remain in a misaligned state with respect to the movable mold 27. In this case, when the fixed mold 26 and the movable mold 27 are closed in the next mold clamping step S101, the molded product that could not be removed will be caught between the fixed mold 26 and the movable mold 27.

[0085] When a molded product is sandwiched between the fixed die 26 and the movable die 27, if the mold is clamped in this state, the molded product may be pressed against the die 25 by the clamping force of the die opening and closing mechanism 40, which may damage the die 25. For this reason, when the movable die 22, which is separated from the fixed die 21, is moved to the side where the fixed die 21 is located in order to close the die with a low-pressure clamping force, if the thrust of the movable die 22 moved by the die opening and closing mechanism 40 does not reach the movable die thrust limit TL and the position of the movable die 22 reaches the die advance limit confirmation position ML, the control device 100 determines that the movable die 27 has come into contact with the fixed die 26 without sandwiching a foreign object between them.

[0086] In contrast, when the movable die 22 is moved to the side where the fixed die 21 is located, if the position of the movable die 22 cannot reach the die advance limit confirmation position ML, the control device 100 determines that a foreign object is caught between the movable die 27 and the fixed die 26. In other words, if the position of the movable die 22 cannot reach the die advance limit confirmation position ML, the control device 100 determines that a foreign object is caught between the movable die 27 and the fixed die 26 and therefore the movement of the movable die 22 is being hindered by the foreign object.

[0087] In addition, when the thrust of the moving die 22 moved by the mold opening / closing mechanism 40 reaches the moving die thrust limit TL when the moving die 22 is moved to the side where the fixed die 21 is located, the control device 100 also determines that a foreign object is sandwiched between the moving die 27 and the fixed die 26. In other words, when the thrust of the moving die 22 reaches the moving die thrust limit TL, the control device 100 determines that the moving die 27 is approaching the fixed die 26 while crushing the foreign object sandwiched between the moving die 27 and the fixed die 26, and determines that a foreign object is sandwiched between the moving die 27 and the fixed die 26. When it is determined that a foreign object is sandwiched between the moving die 27 and the fixed die 26, the control device 100 notifies the operator that a foreign object is sandwiched in the die 25 by displaying on the display unit 101 that a foreign object is sandwiched or by emitting a sound from a speaker (not shown).

[0088] The control device 100 determines whether or not a foreign object is trapped in the mold 25 based on the position of the movable die 22 and the thrust of the movable die 22 when the mold is closed, but the position of the movable die 22 when the mold is closed and the thrust of the movable die 22 when the mold is closed differ depending on the mold 25.

[0089] That is, since the thickness of the die 25 in the longitudinal direction Y differs depending on the die 25, the position of the movable die 22 in the longitudinal direction Y relative to the fixed die 21 when the movable die 27 and the fixed die 26 come into contact with each other differs depending on the die 25. In addition, when the movable die 22 moves in the longitudinal direction Y, resistance such as sliding resistance occurs, and the die opening and closing mechanism 40 moves the movable die 22 against the resistance, but the resistance when moving the movable die 22 also differs depending on the die 25.

[0090] For this reason, the die advance limit confirmation position ML and the movable die thrust limit TL, which are set for the position of the movable die 22 when the mold is closed, differ depending on the mold 25 used to mold the molded product. Therefore, when molding a molded product with the injection molding machine 1, the die advance limit confirmation position ML and the movable die thrust limit TL are made to differ depending on the mold 25. In other words, the die advance limit confirmation position ML and the movable die thrust limit TL are set to values ​​suitable for the mold 25 every time the mold 25 is replaced, and are stored in the memory unit of the control device 100.

[0091] <How to set the mold protection value V> Next, a method for setting the mold protection set value V in this embodiment will be described. In the method for setting the mold protection set value V in this embodiment, the mold protection set value V is set based on data showing the relationship between the movable die thrust force T, which is the force that moves the movable die 22 to the side where the fixed die 21 is located by the mold opening and closing mechanism 40, and the movable die position M, which is the position of the movable die 22 in the movement direction.

[0092] Fig. 6 is an explanatory diagram showing the relationship between the moving die thrust force T and the moving die position M when the mold is closed and opened. Fig. 6 shows the relationship between the moving die thrust force T and the moving die position M when a test was conducted in which the mold was closed with a low-pressure clamping force and then opened. In Fig. 6, the horizontal axis is the time axis, and the vertical axis is the magnitude of the thrust for the moving die thrust force T, and the distance in the longitudinal direction Y from the position of the moving die 22 when the mold was closed with the maximum low-pressure clamping force for the moving die position M.

[0093] When the moving die 22 is moved toward the fixed die 21 while the moving die 27 is separated from the fixed die 26, the moving die thrust force T is gradually increased. As a result, the moving die 22 moves in the longitudinal direction Y in a direction approaching the fixed die 21, and the moving die position M gradually becomes smaller.

[0094] By gradually increasing the moving die thrust T to move the moving die 22 to the side where the fixed die 21 is located, the increase in the moving die thrust T is stopped when the moving die 27 reaches a position where it contacts the fixed die 26. This stops the change in the moving die position M, i.e., stops the movement of the moving die 22. When closing the mold, the moving die 22 is moved to the side where the fixed die 21 is located in this way, and the moving die 27 presses against the fixed die 26, performing a so-called pressing operation.

[0095] When it is time to open the mold, the moving die thrust T is gradually reduced, in contrast to when closing the mold. As a result, the moving die 22 moves in the longitudinal direction Y away from the fixed die 21, and the moving die position M gradually increases. As a result, the moving die 27 arranged on the moving die 22 moves away from the fixed die 26 arranged on the fixed die 21, and the mold is opened. When opening the mold, the moving die 22 is moved away from the fixed die 21 from the state in which the moving die 27 is pressed against the fixed die 26, and the pressure of the moving die 27 against the fixed die 26 is removed, a so-called depressurization operation is performed.

[0096] Fig. 7 is a detailed view of part B in Fig. 6, and is an explanatory diagram showing the relationship between the moving die thrust force T and the moving die position M during the pressing operation. Fig. 8 is a detailed view of part C in Fig. 6, and is an explanatory diagram showing the relationship between the moving die thrust force T and the moving die position M during the depressurization operation. Note that Figs. 7 and 8 are different from Fig. 6 in that the vertical axis represents the magnitude of the moving die thrust force T, and the horizontal axis represents the moving die position M, which is represented in the direction from the left side of the paper to the mold opening direction and from the right side of the paper to the mold closing direction.

[0097] Figure 7 is a graph showing the relationship between the moving die thrust force T and the moving die position M as sample data SD, which are measured when tests of the pressing operation were performed multiple times. When performing the pressing operation, as can be seen from the sample data SD in Figure 7, which is made up of actual measurements from multiple tests, the moving die position M moves in the mold closing direction as the moving die thrust force T increases.

[0098] Figure 8 is a graph showing the relationship between the moving die thrust force T and the moving die position M as sample data SD, which are measured when tests for the depressurization operation were performed multiple times. When performing the depressurization operation, as can be seen from the sample data SD in Figure 8, which is made up of actual measurements from multiple tests, the moving die position M moves in the mold opening direction as the moving die thrust force T decreases.

[0099] 7 and 8, when the mold is closed and opened, the moving die thrust force T and the moving die position M are related to each other in both the pressing operation and the depressurizing operation. The method for setting the mold protection set value V according to this embodiment focuses on this point and calculates the mold protection set value V based on thrust position relationship data F that indicates the relationship between the moving die thrust force T and the moving die position M.

[0100] <How to set the mold protection value V by depressurization> The die protection set value V is set using at least one of the thrust force positional relationship data F during the depressurization operation and the thrust force positional relationship data F during the pressing operation. Therefore, in this embodiment, in order to obtain the thrust force positional relationship data F, data is collected to obtain the relationship between the moving die thrust T and the moving die position M, and the thrust force positional relationship data F is calculated based on the obtained data, and then the die protection set value V is set based on the thrust force positional relationship data F.

[0101] The die protection set value V includes a die advance limit confirmation position ML and a moving die thrust limit TL, and in this embodiment, one of the die advance limit confirmation position ML and the moving die thrust limit TL is used to calculate the other based on the thrust position relationship data F. First, a method for setting the die advance limit confirmation position ML of the die protection set value V using the thrust position relationship data F during depressurization operation will be described.

[0102] <How to set the die advance limit confirmation position ML by depressurization> FIG. 9 is a flow diagram showing a processing procedure when the die advance limit confirmation position ML is set based on the depressurization operation. FIG. 10 is an explanatory diagram for the case of setting the die advance limit confirmation position ML using the thrust position relationship data F during the depressurization operation. When setting the die advance limit confirmation position ML based on the depressurization operation, first, the contact surfaces of the mold 25 are brought into contact with each other with the force of the low-pressure mold clamping force setting value (step ST11). The low-pressure mold clamping force setting value in this case is a value that can be substantially regarded as the maximum value of the low-pressure mold clamping force, such as the maximum value of the low-pressure mold clamping force or a value that is 99% of the maximum value of the low-pressure mold clamping force. When the contact surfaces of the mold 25 are brought into contact with each other with the force of the low-pressure mold clamping force setting value, the control device 100 controls the mold opening and closing mechanism 40, and applies to the movable die 22 a movable die thrust maximum value Tmax, which is a movable die thrust T in a direction in which the movable die 27 is pressed against the fixed die 26 with the force of the low-pressure mold clamping force setting value.

[0103] Next, the position of the moving die 22 is recorded (step ST12). That is, the control device 100 acquires the moving die position M in a state where the moving die 27 is pressed against the fixed die 26 with the low-pressure clamping force setting value, based on the rotational position of the clamping motor 60 detected by an encoder provided in the clamping motor 60 of the mold opening and closing mechanism 40.

[0104] Next, the moving die thrust force T is gradually reduced (step ST13). That is, the control device 100 controls the mold clamping motor 60 of the mold opening and closing mechanism 40 to gradually reduce the torque of the mold clamping motor 60, thereby gradually reducing the moving die thrust force T.

[0105] When the moving die thrust force T is lowered in this manner, the relationship between the moving die position M and the moving die thrust force T while the moving die thrust force T is being lowered is recorded (step ST14). That is, while gradually lowering the moving die thrust force T, the control device 100 acquires the moving die thrust force T calculated from the torque of the clamping motor 60 and the moving die position M calculated from the rotational position of the clamping motor 60 detected by an encoder provided in the clamping motor 60, and stores the calculated moving die thrust force T and the moving die position M in association with each other in the storage unit of the control device 100.

[0106] The moving die position M and the moving die thrust force T are acquired at regular time intervals that are relatively short while the moving die thrust force T is being lowered, and are associated with each other and stored in the storage unit of the control device 100. As a result, for example, sampling data SD as shown in FIG. 8 is stored in the storage unit of the control device 100.

[0107] When the movable die thrust T, which is reduced by controlling the mold opening and closing mechanism 40 by the control device 100, reaches 0 kN, the recording is stopped (step ST15). In other words, when the movable die thrust T reaches 0 kN, the control device 100 determines that mold opening is complete, and ends recording of the movable die position M and the movable die thrust T in the depressurization operation. In this way, the control device 100 acquires the movable die thrust T for each movable die position M from a state in which the fixed mold 26 and the movable mold 27 are in contact with each other at a low-pressure mold clamping force until the movable die thrust T reaches 0 kN by reducing the movable die thrust T.

[0108] After the moving die position M and the moving die thrust force T during the depressurization operation are recorded, thrust force position relationship data F is obtained from the recorded moving die position M and moving die thrust force T (step ST16). The thrust force position relationship data F is data indicating the relationship between the moving die thrust force T and the moving die position M, and the thrust force position relationship data F is obtained by the control device 100 determining a function that approximates the relationship between the moving die position M and the moving die thrust force T stored while the moving die thrust force T is being lowered.

[0109] The thrust force positional relationship data F is obtained, for example, by finding an nth order polynomial that approximates the relationship between the moving die position M and the moving die thrust T stored while the moving die thrust T is being lowered, or by taking a moving average that approximates the relationship between the moving die position M and the moving die thrust T. In other words, the thrust force positional relationship data F is obtained, for example, by finding an nth order polynomial function that approximates the sampling data SD as shown in FIG.

[0110] The die advance limit confirmation position ML is set based on the thrust positional relationship data F obtained in this manner. When setting the die advance limit confirmation position ML based on the thrust positional relationship data F, a moving die thrust limit TL is determined in advance (step ST17a). The moving die thrust limit TL is an upper limit value of the moving die thrust T that is large enough to perform mold closing against resistance such as sliding resistance during mold closing while suppressing damage to the mold 25 caused by an excessively large mold clamping force when closing the mold from a state in which the fixed mold 26 and the moving mold 27 are separated from each other.

[0111] In order to realize such mold closing, the moving die thrust limit TL uses, for example, a value recommended by the manufacturer of the injection molding machine 1. The moving die thrust limit TL is set to a predetermined value relative to the maximum moving die thrust value Tmax, and in the example shown in Fig. 10, a value of 50% of the maximum moving die thrust value Tmax is set as the moving die thrust limit TL. The predetermined moving die thrust limit TL is input by the operator via the input unit 102.

[0112] When setting the die advance limit confirmation position ML, the die advance limit confirmation position ML corresponding to the moving die thrust limit TL is calculated from the thrust position relationship data F (step ST18a). That is, the control device 100 calculates the moving die position M corresponding to the moving die thrust limit TL set in advance as the die advance limit confirmation position ML based on the thrust position relationship data F. That is, since the thrust position relationship data F is a function showing the relationship between the moving die position M and the moving die thrust T, the moving die position M corresponding to the moving die thrust limit TL is obtained from the thrust position relationship data F, and the obtained moving die position M is calculated as the die advance limit confirmation position ML. In the example shown in FIG. 10, since the moving die thrust limit TL is 50% of the moving die thrust maximum value Tmax, the moving die position M corresponding to 50% of the moving die thrust maximum value Tmax is calculated as the die advance limit confirmation position ML.

[0113] Once the die advance limit confirmation position ML is calculated, a safety margin is added to the calculated die advance limit confirmation position ML (step ST19a). The safety margin in this case is intended to absorb variations in the mechanical operation of the injection molding machine 1. In other words, the safety margin is set so that even if variations occur in the mechanical operation, the moving die position M on the mold opening side of the die advance limit confirmation position ML can be detected as the die advance limit confirmation position ML when the mold is closed with a low pressure mold clamping force. The die advance limit confirmation position ML to which the safety margin is added is used. The safety margin set in this way can be changed at any time by parameters inside the machine.

[0114] <How to set the moving die thrust limit TL by depressurization> Next, a method for setting the moving die thrust limit TL of the die protection set value V using the thrust positional relationship data F during depressurization operation will be described. FIG. 11 is a flow diagram showing a processing procedure when the moving die thrust limit TL is set based on the depressurization operation. FIG. 12 is an explanatory diagram for the case of setting the moving die thrust limit TL using the thrust positional relationship data F during the depressurization operation. When setting the moving die thrust limit TL based on the depressurization operation, steps ST11 to ST16 (see FIG. 11) up to obtaining the thrust positional relationship data F are similar to steps ST11 to ST16 (see FIG. 9) up to obtaining the thrust positional relationship data F when setting the die advance limit confirmation position ML based on the depressurization operation, and therefore description thereof will be omitted.

[0115] The movable die thrust limit TL is set based on the thrust positional relationship data F obtained in this manner. When setting the movable die thrust limit TL based on the thrust positional relationship data F, a die advance limit confirmation position ML is determined in advance (step ST17b). The die advance limit confirmation position ML is the limit position of the movable die position M in the mold closing direction when determining whether or not a foreign object is sandwiched between the fixed mold 26 and the movable mold 27 when the mold is closed from a state in which the fixed mold 26 and the movable mold 27 are separated from each other.

[0116] In order to determine the presence or absence of such foreign matter, the die advance limit confirmation position ML uses, for example, a value recommended by the manufacturer of the injection molding machine 1. The die advance limit confirmation position ML is set to a predetermined size relative to the movable die position M, and in the example shown in Fig. 12, when the movable die position M where the contact surfaces of the dies 25 come into contact with each other at the low pressure mold clamping force setting value is set to 0 mm, the movable die position M where the movable die 22 retreats by 0.3 mm is set as the die advance limit confirmation position ML. The predetermined die advance limit confirmation position ML is input by the operator via the input unit 102.

[0117] When setting the moving die thrust limit TL, the moving die thrust limit TL corresponding to the die advance limit confirmation position ML is calculated from the thrust positional relationship data F (step ST18b). That is, the control device 100 calculates the moving die thrust T corresponding to the die advance limit confirmation position ML set in advance as the moving die thrust limit TL based on the thrust positional relationship data F. That is, since the thrust positional relationship data F is a function showing the relationship between the moving die position M and the moving die thrust T, the moving die thrust T corresponding to the die advance limit confirmation position ML is obtained from the thrust positional relationship data F, and the obtained moving die thrust T is calculated as the moving die thrust limit TL. In the example shown in FIG. 12, the die advance limit confirmation position ML is the moving die position M where the moving die 22 retreats 0.3 mm from the position where the contact surfaces of the molds 25 contact each other, so the moving die thrust limit TL is calculated as the moving die thrust limit TL as the moving die thrust limit TL.

[0118] Once the moving die thrust limit TL is calculated, a safety margin is added to the calculated moving die thrust limit TL (step ST19b). The safety margin in this case is intended to absorb variations in the mechanical operation of the injection molding machine 1. In other words, the safety margin is set so that a moving die thrust T lower than the moving die thrust limit TL can be detected as the moving die thrust limit TL when the mold is closed with a low pressure mold clamping force, even if variations occur in the mechanical operation. The moving die thrust limit TL to which the safety margin is added is used. The safety margin set in this manner can be changed at any time by parameters inside the machine.

[0119] <How to set the die advance limit confirmation position ML by pressing> Next, a method for setting the die advance limit confirmation position ML of the die protection set value V using the thrust position relationship data F during the pressing operation will be described. Fig. 13 is a flow diagram showing a processing procedure for setting the die advance limit confirmation position ML based on the pressing operation. Fig. 14 is an explanatory diagram for setting the die advance limit confirmation position ML using the thrust position relationship data F during the pressing operation. When setting the die advance limit confirmation position ML based on the pressing operation, first, the movable die 22 is advanced to bring the contact surfaces of the die 25 into contact with each other with the force of the low pressure mold clamping force set value (step ST21).

[0120] In this manner, the relationship between the moving die position M and the moving die thrust force T is recorded while the moving die 22 is advanced to bring the contact surfaces of the dies 25 into contact with each other (step ST22). That is, while gradually increasing the moving die thrust force T, the control device 100 acquires the moving die thrust force T calculated from the torque of the clamping motor 60 and the moving die position M calculated from the rotational position of the clamping motor 60 detected by an encoder provided in the clamping motor 60, and stores the calculated moving die thrust force T and moving die position M in association with each other in a storage unit of the control device 100.

[0121] The moving die position M and the moving die thrust force T are acquired at regular time intervals that are relatively short while the moving die thrust force T is being increased, and are associated with each other and stored in the storage unit of the control device 100. As a result, for example, sampling data SD as shown in FIG. 7 is stored in the storage unit of the control device 100.

[0122] By advancing the moving die 22, the recording is stopped when the contact surfaces of the mold 25 are pressed against each other with the force of the low-pressure mold clamping force setting value (step ST23). In other words, when the moving die thrust T when the moving die 22 advances reaches the maximum moving die thrust value Tmax and the mold opening and closing mechanism 40 presses the moving die 27 against the fixed mold 26 with the force of the low-pressure mold clamping force setting value, the control device 100 judges that mold closing is completed and ends recording of the moving die position M and the moving die thrust T in the pressing operation. In this way, the control device 100 acquires the moving die thrust T for each moving die position M from a state in which the fixed mold 26 and the moving die 27 are separated from each other to a state in which the moving die thrust T is increased and the fixed mold 26 and the moving die 27 are brought into contact with each other with the low-pressure mold clamping force.

[0123] After the moving die position M and the moving die thrust T during the pressing operation are recorded, thrust position relationship data F is obtained from the recorded moving die position M and moving die thrust T (step ST24). The thrust position relationship data F is data indicating the relationship between the moving die thrust T and the moving die position M, and the thrust position relationship data F is obtained by the control device 100 determining a function that approximates the relationship between the moving die position M and the moving die thrust T stored while the moving die thrust T is being increased.

[0124] The thrust force positional relationship data F is obtained, for example, by finding an nth order polynomial that approximates the relationship between the moving die position M and the moving die thrust T stored while the moving die thrust T is being increased, or by taking a moving average that approximates the relationship between the moving die position M and the moving die thrust T. In other words, the thrust force positional relationship data F is obtained, for example, by finding an nth order polynomial function that approximates the sampling data SD as shown in FIG.

[0125] The die advance limit confirmation position ML is set based on the thrust positional relationship data F obtained in this manner. When setting the die advance limit confirmation position ML based on the thrust positional relationship data F, a moving die thrust limit TL is determined in advance (step ST25a). For example, a value recommended by the manufacturer of the injection molding machine 1 is used as the moving die thrust limit TL. The moving die thrust limit TL is set to a predetermined magnitude relative to the maximum moving die thrust value Tmax, and in the example shown in FIG. 14, a value of 50% of the maximum moving die thrust value Tmax is set as the moving die thrust limit TL. The predetermined moving die thrust limit TL is input by the operator via the input unit 102.

[0126] When setting the die advance limit confirmation position ML, the die advance limit confirmation position ML corresponding to the moving die thrust limit TL is calculated from the thrust position relationship data F (step ST26a). That is, since the thrust position relationship data F is a function showing the relationship between the moving die position M and the moving die thrust T, the control device 100 calculates the moving die position M corresponding to the moving die thrust limit TL from the thrust position relationship data F, and calculates the obtained moving die position M as the die advance limit confirmation position ML. In the example shown in FIG. 14, since the moving die thrust limit TL is 50% of the moving die thrust maximum value Tmax, the moving die position M corresponding to 50% of the moving die thrust maximum value Tmax is calculated as the die advance limit confirmation position ML.

[0127] After the die advance limit confirmation position ML is calculated, a safety margin is added to the calculated die advance limit confirmation position ML (step ST27a). The die advance limit confirmation position ML to which the safety margin is added is used.

[0128] <How to set the moving die thrust limit TL by pressing> Next, a method for setting the moving die thrust limit TL of the die protection set value V using the thrust positional relationship data F during the pressing operation will be described. FIG. 15 is a flow diagram showing a processing procedure when the moving die thrust limit TL is set based on the pressing operation. FIG. 16 is an explanatory diagram for the case of setting the moving die thrust limit TL using the thrust positional relationship data F during the pressing operation. When setting the moving die thrust limit TL based on the pressing operation, steps ST21 to ST24 (see FIG. 15) up to obtaining the thrust positional relationship data F are similar to steps ST21 to ST24 (see FIG. 13) up to obtaining the thrust positional relationship data F when setting the die advance limit confirmation position ML based on the pressing operation, and therefore description thereof will be omitted.

[0129] The movable die thrust limit TL is set based on the thrust positional relationship data F obtained in this way. When setting the movable die thrust limit TL based on the thrust positional relationship data F, a die advance limit confirmation position ML is determined in advance (step ST25b). For example, the die advance limit confirmation position ML is set to a value recommended by the manufacturer of the injection molding machine 1. The die advance limit confirmation position ML is set to a predetermined size with respect to the movable die position M. In the example shown in FIG. 16, when the movable die position M where the contact surfaces of the molds 25 contact each other at the low pressure mold clamping force setting value is set to 0 mm, the movable die position M where the movable die 22 retreats by 0.3 mm is set as the die advance limit confirmation position ML. The predetermined die advance limit confirmation position ML is input by the operator through the input unit 102.

[0130] When setting the moving die thrust limit TL, the moving die thrust limit TL corresponding to the die advance limit confirmation position ML is calculated from the thrust positional relationship data F (step ST26b). That is, since the thrust positional relationship data F is a function showing the relationship between the moving die position M and the moving die thrust T, the control device 100 calculates the moving die thrust T corresponding to the die advance limit confirmation position ML from the thrust positional relationship data F, and calculates the obtained moving die thrust T as the moving die thrust limit TL. In the example shown in FIG. 16, since the die advance limit confirmation position ML is the moving die position M where the moving die 22 retreats by 0.3 mm from the position where the contact surfaces of the molds 25 contact each other, the moving die thrust limit TL is calculated as the moving die thrust limit TL to be the moving die thrust T corresponding to the moving die position M of 0.3 mm.

[0131] After the moving die thrust limit TL is calculated, a safety margin is added to the calculated moving die thrust limit TL (step ST27b). The moving die thrust limit TL to which the safety margin is added is used in this manner.

[0132] <How to set the die advance limit confirmation position ML using both pressing and depressurization> When setting the die protection set value V using the thrust positional relationship data F, the thrust positional relationship data F during the pressing operation and the thrust positional relationship data F during the depressurizing operation may be used in combination to set the die protection set value V. Next, a method for setting the die advance limit confirmation position ML of the die protection set value V using the thrust positional relationship data F during the pressing operation and the thrust positional relationship data F during the depressurizing operation in combination will be described.

[0133] 17 is a flow chart showing a processing procedure when the die forward movement limit confirmation position ML is set by using the pressing operation and the depressurization operation in combination. When the moving die thrust limit TL is set by using the thrust position relationship data F during the pressing operation and the thrust position relationship data F during the depressurization operation in combination, first, the moving die 22 is advanced to bring the contact surfaces of the mold 25 into contact with each other with the force of the low pressure mold clamping force setting value (step ST31). In this way, in step ST31 where the contact surfaces of the mold 25 are brought into contact with each other, the control device 100 controls the mold opening and closing mechanism 40 from a state where the fixed mold 26 and the moving mold 27 are separated from each other, thereby increasing the moving die thrust T, and the moving die thrust T for each moving die position M until the fixed mold 26 and the moving mold 27 are brought into contact with each other with the low pressure mold clamping force is acquired.

[0134] Next, the moving die thrust force T is gradually reduced from the state in which the contact surfaces of the dies 25 are in contact with each other (step ST32). In step ST32 in which the moving die thrust force T is gradually reduced in this manner, the control device 100 controls the die opening and closing mechanism 40 from the state in which the fixed die 26 and the moving die 27 are in contact with each other with a low-pressure mold clamping force, thereby reducing the moving die thrust force T and acquiring the moving die thrust force T for each moving die position M until the moving die thrust force T becomes 0 kN.

[0135] Next, thrust positional relationship data F for both the "pressing operation" and the "depressurizing operation" is obtained (step ST33). That is, in step ST31, thrust positional relationship data F obtained from the moving die position M and the moving die thrust T obtained while increasing the moving die thrust T from a state in which the fixed die 26 and the moving die 27 are separated is obtained as first thrust positional relationship data, which is thrust positional relationship data F due to the pressing operation. Also, in step ST32, thrust positional relationship data F obtained from the moving die position M and the moving die thrust T obtained while decreasing the moving die thrust T from a state in which the fixed die 26 and the moving die 27 are in contact with each other with a low-pressure mold clamping force is obtained as second thrust positional relationship data, which is thrust positional relationship data F due to the depressurizing operation.

[0136] The die advance limit confirmation position ML is set based on the thrust positional relationship data F due to the pressing operation and the thrust positional relationship data F due to the depressurization operation obtained in this manner. When setting the die advance limit confirmation position ML based on the thrust positional relationship data F, a moving die thrust limit TL is determined in advance (step ST34a). For the moving die thrust limit TL, for example, a value recommended by the manufacturer of the injection molding machine 1 is used. The predetermined moving die thrust limit TL is input by the operator via the input unit 102.

[0137] When setting the die advance limit confirmation position ML, the control device 100 calculates the die advance limit confirmation position ML corresponding to the moving die thrust limit TL from the thrust position relationship data F of the pressing operation and the thrust position relationship data F of the depressurization operation (step ST35a). That is, the control device 100 calculates the moving die position M corresponding to the moving die thrust limit TL from the thrust position relationship data F of the pressing operation, and calculates the obtained moving die position M as the die advance limit confirmation position ML of the pressing operation. Also, the control device 100 calculates the moving die position M corresponding to the moving die thrust limit TL from the thrust position relationship data F of the depressurization operation, and calculates the obtained moving die position M as the die advance limit confirmation position ML of the depressurization operation.

[0138] Next, the average of the die advance limit confirmation position ML of the pressing operation and the die advance limit confirmation position ML of the depressurizing operation is calculated (step ST36a). This calculates the die advance limit confirmation position ML based on the thrust position relationship data F of the pressing operation and the thrust position relationship data F of the depressurizing operation.

[0139] After calculating the average of the die advance limit confirmation position ML, a safety margin is added to the calculated average value of the die advance limit confirmation position ML (step ST37a). The die advance limit confirmation position ML to which the safety margin is added is used.

[0140] <How to set the moving die thrust limit TL using both pressing and depressurizing> Next, a method for setting the moving die thrust limit TL of the die protection setting value V using the thrust position relationship data F during the pressing operation and the thrust position relationship data F during the depressurization operation will be described.

[0141] Fig. 18 is a flow diagram showing a processing procedure when the moving die thrust limit TL is set by using the pressing operation and the depressurizing operation in combination. When the moving die thrust limit TL is set by using the pressing operation and the depressurizing operation in combination, steps ST31 to ST33 (see Fig. 18) up to obtaining thrust positional relationship data F are similar to steps ST31 to ST33 (see Fig. 17) up to obtaining thrust positional relationship data F in setting the die advance limit confirmation position ML by using the pressing operation and the depressurizing operation in combination, and therefore description thereof will be omitted.

[0142] The movable die thrust limit TL is set based on the thrust positional relationship data F due to the pressing operation and the thrust positional relationship data F due to the depressurization operation obtained in this manner. When setting the movable die thrust limit TL based on the thrust positional relationship data F, the die advance limit confirmation position ML is determined in advance (step ST34b). For example, the die advance limit confirmation position ML is a value recommended by the manufacturer of the injection molding machine 1. The predetermined die advance limit confirmation position ML is input by the operator via the input unit 102.

[0143] When setting the moving die thrust limit TL, the moving die thrust limit TL corresponding to the die forward limit confirmation position ML is calculated from the thrust position relationship data F of the pressing operation and the thrust position relationship data F of the depressurizing operation (step ST35b). That is, the control device 100 calculates the moving die thrust T corresponding to the die forward limit confirmation position ML from the thrust position relationship data F of the pressing operation, and calculates the obtained moving die thrust T as the moving die thrust limit TL of the pressing operation. Also, the control device 100 calculates the moving die thrust T corresponding to the die forward limit confirmation position ML from the thrust position relationship data F of the depressurizing operation, and calculates the obtained moving die thrust T as the moving die thrust limit TL of the depressurizing operation.

[0144] Next, the average of the moving die thrust limit TL for the pressing operation and the moving die thrust limit TL for the depressurizing operation is calculated (step ST36b). This allows the moving die thrust limit TL to be calculated based on the thrust positional relationship data F for the pressing operation and the thrust positional relationship data F for the depressurizing operation.

[0145] After the average of the moving die thrust limit TL is calculated, a safety margin is added to the calculated average value of the moving die thrust limit TL (step ST37b). The moving die thrust limit TL to which the safety margin is added is used in this manner.

[0146] The mold protection setting value V is set by calculating at least one of the thrust force positional relationship data F during the depressurization operation and the thrust force positional relationship data F during the pressing operation as described above, and using at least one of the thrust force positional relationship data F.

[0147] The mold protection set value V is set every time the mold 25 of the injection molding machine 1 is replaced. When setting the mold protection set value V, the operator inputs an input instruction to the input unit 102 to cause the injection molding machine 1 to set the mold protection set value V after replacing the mold 25. At that time, the operator also inputs which of the above-mentioned methods is used to set the mold protection set value V. As a result, the injection molding machine 1 sets the mold protection set value V by the input method. That is, the control device 100 of the injection molding machine 1 calculates the die advance limit confirmation position ML or the moving die thrust limit TL by the input method. When molding a molded product with the injection molding machine 1, the control device 100 uses the calculated mold protection set value V to control mold closing, thereby determining whether or not a foreign object is caught between the molds 25 when the molds are closed, and protecting the molds 25 when the molds are closed.

[0148] <Effects of the embodiment> The injection molding machine 1 and the method for setting the mold protection set value V according to the above embodiment obtain thrust positional relationship data F indicating the relationship between the moving die thrust T and the moving die position M, and calculate the mold protection set value V at the time of closing the mold with a low pressure mold clamping force based on the thrust positional relationship data F, so that the mold protection set value V can be set without relying on the experience of the operator who operates the injection molding machine 1. In addition, since the mold protection set value V is calculated based on the thrust positional relationship data F, when setting the mold protection set value V, it is not necessary to repeatedly close and open the mold while observing the state of the mold 25, so that the time required for setting the mold protection set value V can be shortened. In addition, since the mold protection set value V is calculated by the control device 100 based on the thrust positional relationship data F, it is possible to reduce the number of items that the operator sets when performing molding using the injection molding machine 1, and human error can be suppressed. As a result of these, the set value used for protecting the mold 25 at the time of closing the mold can be easily set.

[0149] Moreover, the die protection set value V is the die advance limit confirmation position ML and the moving die thrust limit TL, and since one of the die advance limit confirmation position ML and the moving die thrust limit TL is used to calculate the other based on the thrust positional relationship data F, it is possible to easily set both the die advance limit confirmation position ML and the moving die thrust limit TL. As a result, it is possible to easily set the set value used to protect the die 25 when the die is closed.

[0150] Furthermore, since the moving die position M corresponding to the preset moving die thrust limit TL is calculated as the die advance limit confirmation position ML based on the thrust position relationship data F, it is possible to easily calculate the moving die position M used to determine whether or not a foreign object is caught by the die 25 when the die is closed. As a result, it is possible to easily set the setting value used to protect the die 25 when the die is closed, and it is possible to more reliably protect the die 25 when the die is closed.

[0151] Furthermore, since the moving die thrust T corresponding to a preset die advance limit confirmation position ML is calculated as the moving die thrust limit TL based on the thrust positional relationship data F, it is possible to easily calculate the moving die thrust T capable of suppressing damage to the die 25 caused by the die 25 coming into contact with each other due to a large clamping force when the die is closed. As a result, it is possible to easily set a setting value used for protecting the die 25 when the die is closed, and it is possible to more reliably protect the die 25 when the die is closed.

[0152] In addition, when obtaining the thrust positional relationship data F, the moving die thrust T for each moving die position M is obtained from the state in which the contact surfaces of the mold 25 are in contact with each other until the moving die thrust T becomes 0 kN by reducing the moving die thrust T, and the thrust positional relationship data F can be obtained from the obtained moving die position M and moving die thrust T. As a result, the moving die thrust T for each moving die position M is obtained while reducing the moving die thrust T from the state in which the mold is clamped with a low pressure mold clamping force, so that the moving die thrust T for each moving die position M can be obtained in a short time. Therefore, when obtaining the thrust positional relationship data F according to the replaced mold 25 after replacing the mold 25, the thrust positional relationship data F can be obtained in a short time, so that the mold protection setting value V can be calculated in a short time based on the thrust positional relationship data F. As a result, the setting value used for protecting the mold 25 at the time of mold closing can be easily set in a short time.

[0153] In addition, when obtaining the thrust positional relationship data F, the movable die thrust T for each movable die position M from the state where the fixed die 26 and the movable die 27 are separated to the state where the contact surfaces of the die 25 are brought into contact with each other by increasing the movable die thrust T can be obtained, and the thrust positional relationship data F can be obtained from the obtained movable die position M and movable die thrust T. As a result, the thrust positional relationship data F can be obtained based on the movable die thrust T for each movable die position M from the state where the fixed die 26 and the movable die 27 are separated to the state where the die is closed with a low pressure mold clamping force, so that the thrust positional relationship data F can be obtained based on the movable die position M and the movable die thrust T that correspond to the operation during actual molding. Therefore, when obtaining the thrust positional relationship data F according to the replaced die 25 after replacing the die 25, the thrust positional relationship data F with high accuracy that corresponds to the operation during actual molding can be obtained, so that the die protection setting value V can be calculated with high accuracy based on the thrust positional relationship data F. As a result, the setting value used for protecting the die 25 during die closing can be easily set with high accuracy.

[0154] Moreover, the die protection set value V can be calculated based on first thrust positional relationship data obtained from the moving die position M and the moving die thrust T obtained while increasing the moving die thrust T, and second thrust positional relationship data obtained from the moving die position M and the moving die thrust T obtained while decreasing the moving die thrust T. This allows the die protection set value V to be calculated based on more thrust positional relationship data F, so that the die protection set value V can be calculated with high accuracy. As a result, the set value used for protecting the die 25 when the die is closed can be easily set with high accuracy.

[0155] [Variations] In the above-described embodiment, an example of determining the die advance limit confirmation position ML as the mold protection setting value V and an example of determining the movable die thrust limit TL have been described, but the injection molding machine 1 may be capable of determining both of these, or may be capable of determining only one of them.

[0156] In addition, in the above-described embodiment, the methods of obtaining the thrust position relationship data F have been described as follows: a method of obtaining the thrust position relationship data F by a depressurizing operation, a method of obtaining the thrust position relationship data F by a pressing operation, and a method of obtaining the thrust position relationship data F by combining the pressing operation and the depressurizing operation. However, the injection molding machine 1 may be capable of using any of these methods, or may be capable of using some of them.

[0157] In addition, in the above-described embodiment, the calculation of the thrust positional relationship data F has been described as one of the steps in the method for setting the mold protection setting value V, but the calculation of the thrust positional relationship data F may be performed within another function of the injection molding machine 1, and the thrust positional relationship data F calculated by the other function may be used to set the mold protection setting value V. [Explanation of symbols]

[0158] 1...injection molding machine, 5...frame, 6...cover, 10...injection unit, 11...injection cylinder, 12...nozzle, 13...screw, 14...hopper, 20...mold clamping unit, 21...fixed die, 22...movable die, 25...mold, 26...fixed die, 27...movable die, 30...link housing, 40...mold opening / closing mechanism, 41...toggle link, 42...crosshead side link, 43...link housing side link, 44...movable die side link, 45...toggle link connection portion, 50...drive unit, 51...ball screw, 52...crosshead head, 53...nut, 60...mold clamping motor, 61...first pulley, 62...second pulley, 63...timing belt, 70...tie bar, 75...tie bar sensor, 80...mold thickness adjustment mechanism, 81...tie bar nut, 84...mold thickness adjustment motor, 85...driving gear, 86...annular gear, 87...tie bar nut gear, 90...first linear guide, 91...first guide rail, 92...first block, 95...second linear guide, 96...second guide rail, 97...second block, 100...control device, 101...display unit, 102...input unit

Claims

1. a fixed die to which the fixed die is attached, the fixed die being one of a pair of dies consisting of a fixed die and a movable die; a movable die to which the movable mold is attached and which is disposed in a direction facing the fixed mold attached to the fixed die; a mold opening and closing mechanism that opens and closes the movable metal mold and the fixed metal mold attached to the movable die and clamps the molds by moving the movable die in a direction in which the distance between the movable die and the fixed die changes using a driving force generated by a mold clamping motor that is a power source; A control device for controlling the mold opening and closing mechanism; Equipped with The control device includes: Based on thrust position relationship data indicating a relationship between a movable die thrust, which is a force for moving the movable die to a side where the fixed die is located by the mold opening and closing mechanism, and a movable die position, which is a position in a moving direction of the movable die, An injection molding machine characterized by calculating a mold protection setting value, which is a setting value for the operation of the movable die to protect the mold when the mold is closed at a low-pressure mold clamping force that is set as a clamping force lower than the maximum mold clamping force by the mold opening and closing mechanism.

2. The mold protection setting value is a die advance limit confirmation position that is set as the movable die position where the movable die is slightly separated from the position where the fixed die and the movable die are in contact with each other by the low pressure mold clamping force, with respect to the fixed die; a movable die thrust limit that is set as an upper limit value of the movable die thrust when the mold is closed with the low-pressure mold clamping force; 2. The injection molding machine according to claim 1, wherein the control device uses one of the die advance limit confirmation position and the movable die thrust limit to calculate the other based on the thrust position relationship data.

3. 3. The injection molding machine according to claim 2, wherein the control device calculates, based on the thrust-position relationship data, the moving die position corresponding to the preset moving die thrust limit as the die advance limit confirmation position.

4. 3. The injection molding machine according to claim 2, wherein the control device calculates, as the moving die thrust limit, the moving die thrust corresponding to a preset die advance limit confirmation position based on the thrust position relationship data.

5. a fixed die to which the fixed die is attached, the fixed die being one of a pair of dies consisting of a fixed die and a movable die; a movable die to which the movable mold is attached and which is disposed in a direction facing the fixed mold attached to the fixed die; a mold opening and closing mechanism that opens and closes the movable metal mold and the fixed metal mold attached to the movable die and clamps the molds by moving the movable die in a direction in which the distance between the movable die and the fixed die changes using a driving force generated by a mold clamping motor that is a power source; A method for setting a mold protection setting value, which is a setting value for an operation of the movable die for protecting the mold when closing the mold with a low-pressure mold clamping force that is set as a mold clamping force lower than a maximum mold clamping force by the mold opening and closing mechanism in an injection molding machine comprising: a step of obtaining thrust position relationship data indicating a relationship between a movable die thrust, which is a force for moving the movable die to a side where the fixed die is located by the mold opening and closing mechanism, and a movable die position, which is a position in a moving direction of the movable die; calculating the die protection setting value based on the thrust position relationship data; 11. A method for setting a mold protection setting value, comprising:

6. The mold protection setting value is a die advance limit confirmation position that is set as the movable die position where the movable die is slightly separated from the position where the fixed die and the movable die are in contact with each other by the low pressure mold clamping force, with respect to the fixed die; a movable die thrust limit that is set as an upper limit value of the movable die thrust when the mold is closed with the low-pressure mold clamping force; A method for setting a mold protection setting value as described in claim 5, wherein in the step of calculating the mold protection setting value, one of the die advance limit confirmation position and the moving die thrust limit is used to calculate the other based on the thrust position relationship data.

7. The procedure for obtaining the thrust-position relationship data includes: a step of acquiring the moving die thrust for each moving die position from a state in which the fixed die and the moving die are in contact with each other under the low-pressure clamping force until the moving die thrust becomes 0 kN; A step of obtaining the thrust position relationship data from the acquired moving die position and the acquired moving die thrust; 7. The method for setting a mold protection setting value according to claim 5 or 6, comprising:

8. The procedure for obtaining the thrust-position relationship data includes: a step of acquiring the moving die thrust for each moving die position from a state in which the fixed die and the moving die are separated to a state in which the fixed die and the moving die are brought into contact with each other by the low-pressure clamping force; A step of obtaining the thrust position relationship data from the acquired moving die position and the acquired moving die thrust; 7. The method for setting a mold protection setting value according to claim 5 or 6, comprising:

9. The procedure for obtaining the thrust-position relationship data includes: a step of acquiring the moving die thrust for each moving die position from a state in which the fixed die and the moving die are separated to a state in which the fixed die and the moving die are brought into contact with each other by the low-pressure clamping force; a step of acquiring the moving die thrust for each moving die position from a state in which the fixed die and the moving die are in contact with each other under the low-pressure clamping force until the moving die thrust becomes 0 kN; a step of obtaining first thrust positional relationship data, which is thrust positional relationship data obtained from the movable die position and the movable die thrust obtained while increasing the movable die thrust from a state in which the fixed die and the movable die are separated from each other; a step of obtaining second thrust positional relationship data, which is thrust positional relationship data obtained from the movable die position and the movable die thrust obtained while reducing the movable die thrust from a state in which the fixed die and the movable die are in contact with each other under the low-pressure mold clamping force; Including, The method for setting a mold protection setting value according to claim 5 or 6, wherein in the step of calculating the mold protection setting value, the mold protection setting value is calculated based on the first thrust position relationship data and the second thrust position relationship data.

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