JP4748891B2 - Injection molding machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vertical injection molding machine, and more particularly to an injection molding machine suitable for use in molding a molded product that requires extremely high plate thickness accuracy, such as a next-generation optical disk.
[0002]
[Prior art]
In the current CD-ROM, the plate thickness accuracy (difference between the maximum plate thickness and the minimum plate thickness) is required to be about 20 μm. However, the current CD-R requires a plate thickness accuracy of about 15 μm, the DVD-9 requires a plate thickness accuracy of about 10 μm, and the DVD-RAM and DVD-R require a plate thickness accuracy of about 5 μm. Has been. As described above, the demand for the plate thickness accuracy of the optical disc is gradually becoming strict, and the plate thickness accuracy is required to be about 1 to 2 μm in the next-generation optical disc aiming for a large capacity.
[0003]
FIG. 8 is a view showing a conventional horizontal type (a type in which a movable die plate moves left and right). In the figure, 51 is a fixed die plate to which a fixed mold 52 is attached, 53 is a support plate on which a servo motor 54 as a drive source for opening and closing the mold is mounted, and 55 is between the fixed die plate 51 and the support plate 53. Four tie bars laid on the tie bar, 56 is a movable die plate that is inserted into the tie bar 55 and can be moved to the left and right in the figure, 57 is a movable mold attached to the movable die plate 56, and 58 is a servo motor 54 rotating. A ball screw mechanism 59 for converting to linear motion, 59 is a toggle link mechanism for transmitting the linear motion of the ball screw mechanism 58 to the movable die plate 56.
[0004]
In the configuration shown in FIG. 8, when the servo motor 54 rotates in a predetermined direction when the fixed die plate 54 is at the mold closing start position, the rotation of the servo motor 54 is converted into a linear motion by the ball screw mechanism 58. The force is transmitted to the movable die plate 56 through the toggle link mechanism 59, and the movable die plate 56 is driven forward in the rightward direction in the figure. Further, when the fixed die plate 54 is at the mold opening start position and the servo motor 54 rotates in the opposite direction, the movable die plate 56 is driven backward in the leftward direction in the figure by the same transmission mechanism.
[0005]
By the way, in the injection molding machine shown in FIG. 8, in order to ensure good plate thickness accuracy, it is necessary to make the parallelism between the fixed side mold 52 and the movable side mold 57 as good as possible. Even if the machining accuracy and assembly accuracy of the mechanism are increased as much as possible, the parallelism is limited to about 1/100. In this way, if the parallelism is about 1/100 even if the maximum effort is made, the plate thickness accuracy can only be about a few tens of μm. It will be difficult.
[0006]
Therefore, conventionally, the axial force of each tie bar 55 is finely adjusted individually by repeating trial shots and retry adjustments, and the parallelism between the fixed mold 52 and the movable mold 57 is obtained. . This adjustment is achieved by providing a known die height adjusting mechanism (not shown) independently for each tie bar 55 and finely adjusting the rotational position of the tightening nut 60 of the tie bar 55.
[0007]
However, even if the method of adjusting the axial force of each tie bar 55 as described above is used, it is difficult to cope with an optical disc that requires a plate thickness accuracy of about 1 to 2 μm, as in a next-generation optical disc. In any case, in the horizontal injection molding machine, the deformation amount of the fixed die plate 51 due to the axial force (tightening force) of the tie bar 55 is such that the lower part on the fixed side and the upper part not on the fixed side as shown in FIG. The amount of deformation of the movable die plate 56 is slightly different between the lower part and the upper part, and the amount of deformation of the two die plates 51 and 56 is influenced by the weight of the mold. This is because the parallelism between the fixed side mold 52 and the movable side mold 57 is naturally limited due to a slight difference between the lower part and the upper part. Furthermore, in a horizontal injection molding machine, there is also an influence on the plate thickness accuracy due to the molten resin being affected by gravity.
[0008]
On the other hand, in the vertical mold clamping apparatus disclosed in Japanese Patent Laid-Open No. 5-269748, there are four sets of servo motors and ball screw mechanisms, and each ball screw mechanism is driven by an individual servo motor. Therefore, even if the resin reaction force acts unbalanced on the mold due to the difference in resin pressure that occurs in the case of a left-right asymmetric molded product, the servo motors are opened and closed. By performing adaptive control individually, the mold release surface is prevented from opening.
[0009]
[Problems to be solved by the invention]
As described above, in the conventional horizontal injection molding machine, even if the parallelism is corrected by adjusting the axial force of the tie bar, due to the structural problem of the horizontal mechanism, the correction of the parallelism is necessary. In the vertical mold clamping apparatus described in Japanese Patent Laid-Open No. 5-269748, it is difficult to cope with an optical disk that has a certain limit and requires a plate thickness accuracy of about 1 to 2 μm. In addition, the problems arising from the horizontal mechanism (horizontal injection molding machine) can be cleared, and the axial force can be adjusted individually. However, in the technique of this publication, like a general injection molding machine, the fixed side mold and the movable side mold are in close contact with each other in the mold clamping state (the horizontal surface (release surface) of the fixed side mold and the movable side mold are movable). The horizontal mold (release surface) of the side mold is in close contact. For this reason, after all, the parallelism between the fixed side mold and the movable side mold in the mold clamping state depends on the planar accuracy of the mold release surface and the assembly accuracy of the mechanism. It is impossible to cope with an optical disk that requires a plate thickness accuracy of about 1 to 2 μm.
[0010]
The present invention has been made in view of the above points, and its object is to correct the parallelism between the movable side mold and the fixed side mold as much as possible, and thus, An object of the present invention is to provide an injection molding machine capable of good quality molding of next-generation optical discs that require a plate thickness accuracy of about 1 to 2 μm.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, the present invention has three or more ball screw mechanisms and a plurality of servo motors that independently drive the ball screw mechanisms, and the linear motion of each ball screw mechanism is controlled by a movable die. In the vertical injection molding machine that opens and closes the mold by moving the movable mold attached to the movable die plate up and down relative to the fixed mold attached to the fixed die plate by transmitting to each plate, Of the movable side mold and the fixed side mold, one mold has a recess formed in a horizontal plane facing the other mold, and the other mold faces the one mold. The pair of molds form a cavity between the bottom surface of the concave portion and the top surface of the convex portion inserted into the concave portion, and the mold opening is completed. Before state In the injection filling standby state in which a cavity is formed by the movable side mold and the fixed side mold, the horizontal surface of the movable side mold and the horizontal surface of the fixed side mold are separated from each other. In each of the above, the respective ball screw mechanisms are controlled so as to correct the parallelism between the movable mold and the fixed mold, and the compression is performed by driving the movable mold after injection filling. Also, the horizontal plane of the movable mold and the horizontal plane of the fixed mold are controlled so as to be separated from each other.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0013]
1 to 5 relate to an injection molding machine according to a first embodiment of the present invention, FIG. 1 is a front view of a main part of the injection molding machine in a mold open state, and FIG. 2 is a view of the injection molding machine from the bottom side. FIG. 3 is a block diagram of a mold opening / closing control system in an injection molding machine, FIG. 4 is a front view of an essential part of an injection molding machine in an injection filling standby state, and FIG. 5 is an essential part of the injection molding machine in a compression completed state. It is a front view.
[0014]
1, 2, 4, and 5, 1 is a fixed die plate fixed on an appropriate base material (not shown), and 2 is a ball screw mechanism provided at the four corners of the lower plate portion 1 a of the fixed die plate 1. Reference numeral 3 denotes a nut portion that is rotatably held through bearings 5 in through holes formed in four corners of the lower plate portion 1a, and 4 is screwed into each nut portion 3 to rotate the nut portion 3. A screw part that moves linearly up and down, 6 is a pulley fixed to each nut part 3, 7 (7A to 7D) is provided for each ball screw mechanism 2, and an appropriate holding member (not shown) is provided on the lower plate part 1a. Servo motors (servo motors “A” to “D”) attached through the shafts 8, 8 are small pulleys fixed to the output shaft of each servo motor 6, and 9 connects the corresponding small pulley 7 and pulley 5. Timing belt (see Fig. 2), 10 is the lower part A load cell sandwiched between the rate portion 1a and the bearing 5.
[0015]
Further, 11 is a shaft member fixed to the upper end of each screw portion 5, and 12 is a spline shaft coupling (relative sliding in the axial direction) provided at the four corners of the upper plate portion 1b of the fixed die plate 1. A shaft holding member which can be moved but cannot be rotated), 13 is a movable die plate in which each shaft member 11 is fixed at its four corners, and 14 is a movable side attached to the lower surface side of the movable die plate 13. A mold 15 is a fixed mold attached to the upper surface of the upper plate portion 1 b of the fixed die plate 1.
[0016]
Here, the parallelism between the movable mold 14 and the fixed mold 15 can be reduced by increasing the machining accuracy and assembly accuracy of the mechanism even in a state where adjustment by an axial force described later is not performed. It is comprised so that it may be about 100 or less.
[0017]
In the above-described configuration, the rotation of each servo motor 7 (7A to 7B) is transmitted to the nut portion 3 of the ball screw mechanism 2 via the small pulley 8, the timing belt 9, and the pulley 6, and the screw portion 4 by the ball screw mechanism 2 is transmitted. Is converted into a linear motion. The linear motion of each screw portion 4 is transmitted to the movable die plate 13 via the shaft member 11, whereby the movable die plate 13 is lowered or raised.
[0018]
FIG. 3 is a diagram showing only the configuration of the mold opening / closing control system for the sake of simplification, and the mold opening / closing control unit 20 shown in FIG. 3 is responsible for controlling the mold opening / closing operation and the compression operation. A control operation is performed based on a command from an upper molding sequence control unit (not shown). The mold opening / closing control unit 20 can provide position / speed target values and torque target values to the servo driver units 21A to 21D that feedback control the servo motors “A” to “D” 7A to 7D. ing. And each servo driver part 21A-21D is the position actual value obtained from the target value from the mold opening / closing control part 20, and the encoder (not shown) provided in each servo motor "A"-"D" 7A-7D. 22A to 22D and the actual measured torque values 23A to 23D obtained from the load cells 10 described above, the servo motors “A” to “D” 7A to 7D are controlled by position / speed feedback control or torque (pressure). Feedback control is provided.
[0019]
In the present embodiment, the servo motors “A” to “A” from the mold opening completion position (that is, the mold closing start position) to the injection filling standby position where the movable mold 14 and the stationary mold 15 form a cavity. "D" 7A to 7D are synchronized, position / speed feedback control along the stroke axis (position axis) is performed, and the movable die plate 13 is driven downward.
[0020]
In the present embodiment, the horizontal plane of the movable mold 14 and the horizontal plane of the fixed mold 15 are separated from each other even at the compression completion position where the movable die plate 13 is further lowered by a small amount from the injection filling standby position. (The conventional movable side mold and the fixed side mold are separated from each other in a surface corresponding to a mold release surface in the close contact type), and when the movable die plate 13 reaches the injection filling standby position, Servo motors “A” to “D” 7A to 7D are individually subjected to position / velocity feedback control, whereby the parallelism is corrected by finely adjusting each axis. That is, before the resin (molten resin) is injected and filled into the cavity, the parallelism is corrected so that the parallelism between the movable mold 14 and the fixed mold 15 is as close to 0 (zero) as possible. It is like that. The control command values for the servo motors “A” to “D” 7A to 7D for obtaining the parallelism have machine differences for each machine. To get.
[0021]
In the present embodiment, the resin is compressed by driving the movable mold 14 (movable die plate 13) from an appropriate timing after the injection and filling of the resin into the cavity is started. In the stroke, the servo motors “A” to “D” 7A to 7D are individually individually subjected to torque (pressure) feedback control along the time axis.
[0022]
The control command values (control set values) to the servo motors “A” to “D” 7A to 7D as described above are the motor A control set value storage unit 20a and the motor B control setting of the mold opening / closing control unit 20, respectively. The values are stored in the value storage unit 20b, the motor C control set value storage unit 20c, and the motor D control set value storage unit 20d, respectively.
[0023]
Next, the operation of this embodiment will be described. First, in the mold opening state (mold opening completion state) shown in FIG. 1, when the mold closing operation start timing is reached, the servo motors “A” to “D” 7A to 7D are synchronously driven by position / speed feedback control. The movable die plate 13 is driven downward by the driving force transmission mechanism described above, whereby the movable die plate 13 is transferred to the injection filling standby position shown in FIG.
[0024]
In the state where the movable die plate 13 reaches the injection filling standby position, a cavity is formed by the movable side mold 14 and the fixed side mold 15, but the horizontal plane of the movable side mold 14 and the horizontal plane of the fixed side mold 15 The servo motors “A” to “D” 7A to 7D are individually subjected to position / speed feedback control so that the movable mold 14 and the fixed mold 15 are parallel to each other. The degree is corrected. Since the injection molding machine of the present invention is a vertical type, there is no problem as in the case of the horizontal type injection molding machine described above. Therefore, the parallelism correction can be performed with extremely high accuracy, and the resin is injected into the cavity. Before filling, the parallelism can be as close to 0 (zero) as possible.
[0025]
When the parallelism correction by the individual axis adjustment described above is completed, injection filling of the resin (molten resin) 16 into the cavity is started by an injection mechanism (not shown). When the resin 16 starts to be clogged in the cavity, the movable side mold 14 receives a reaction force due to the resin. In order to apply a compressive stress to the resin against the resin reaction force, each servo motor “A” to “D” The compression stroke is started by individually controlling torque (pressure) feedback along the time axis for 7A to 7D. In the compression stroke, the torque (that is, the axial force) is controlled so that the actually measured torque value by the load cell follows the torque command value, whereby the resin is uniformly compressed by the downward pressure by the movable mold 14, Control is performed so that the parallelism between the movable mold 14 and the fixed mold 15 is maintained.
[0026]
FIG. 5 shows the compression completed state, and even in this compression completed state, as described above, the horizontal surface of the movable mold 14 and the horizontal plane of the fixed mold 15 are separated from each other. Until the compression is completed, the parallelism between the movable mold 14 and the fixed mold 15 is kept good.
[0027]
When the compression stroke is completed, each servo motor “A” to “D” 7A to 7D is stopped, and after a predetermined cooling period, each servo motor “A” to “D” 7A to 7D is moved to the position / speed. The movable die plate 13 is driven synchronously by feedback control, and the movable die plate 13 is driven up by the above-described driving force transmission mechanism, so that the movable die plate 13 is transferred to the mold opening completion position shown in FIG. Is done. Thereafter, the molded product (optical disk disc and sprue portion) is taken out by appropriate means. In the mold opening completion position, the servo motors “A” to “D” 7A to 7D each take an origin rotation angle position (or a predetermined rotation angle position therefrom).
[0028]
In the present embodiment that employs such a configuration and control method, the parallelism between the movable mold 14 and the fixed mold 15 can be corrected to the best possible one, and the plate thickness accuracy is 1 to 2 μm. It is possible to achieve non-defective molding of next-generation optical discs that require a degree.
[0029]
Further, since the intermediate portion of the shaft member 11 integrated with the screw portion 4 is connected to the shaft holding member 12 fixed to the fixed die plate 1 by the spline shaft, the movable die plate 13 can be stably moved up and down. It becomes. Further, as compared with the above-described mold clamping device disclosed in Japanese Patent Laid-Open No. 5-269748, the movable die can be compared with a configuration in which the long screw portion of the ball screw mechanism is rotatably held with respect to the movable die plate. Since there is no rotating element on the plate 13 side, safety can be improved.
[0030]
Next, a second embodiment of the present invention will be described. FIG. 6 is a front view of an essential part of an injection molding machine according to the second embodiment of the present invention, in which the same reference numerals are assigned to the same components as those in the first embodiment of FIGS. However, the explanation is omitted to avoid duplication.
[0031]
The present embodiment is different from the first embodiment in that, in the first embodiment, the injection filling of the resin into the mold is performed from above or from the side of the movable mold 14. In the embodiment, the resin is injected from the lower side of the fixed mold 15.
[0032]
In FIG. 6, reference numeral 30 denotes a hot runner member embedded in the intermediate plate portion 1 b of the fixed die plate 1, which has a vertical hole 30 a serving as a resin passage and a horizontal hole 30 b continuous therewith. The opening of the nozzle portion 30 c is pressed against a resin injection port provided on the bottom surface of the fixed mold 15. The hot runner member 30 is heated by a heater (not shown). Reference numeral 31 denotes an inline screw type injection unit, which is a heating cylinder 32, a nozzle 33 attached to the tip of the heating cylinder 32, and a screw 34 disposed so as to be able to rotate and move forward and backward in the heating cylinder 32. The opening of the nozzle 33 is pressed against the resin injection port of the horizontal hole 30b of the hot runner member 30.
[0033]
In the present embodiment, when the injection start timing is reached, the screw 34 that has been retracted to the measurement completion position is driven forward, whereby the molten resin stored on the tip side of the screw 34 is transferred to the nozzle 33 and the hot runner member. Through 30 horizontal holes 30 b and vertical holes 30 a, injection filling is performed from the lower side of the fixed mold 15 into a cavity formed by the movable mold 14 and the fixed mold 15.
[0034]
As described above, in this embodiment, since the resin is injected and filled from the lower side of the fixed mold 15, in the state before the injection into the mold, the sprue portion in the vicinity of the resin injection port of the mold is formed. The amount of resin that leaks becomes a small amount of resin due to the action of gravity and becomes uniform, which greatly contributes to good product molding. On the other hand, when the resin is injected and filled from above or from the side of the mold, the amount of resin leaking to the sprue portion in the vicinity of the mold resin injection port in the state before injection into the mold is It becomes comparatively large by the action, and its variation also increases.
[0035]
In FIG. 6, reference numeral 37 denotes a metal plate, 38 denotes a heat insulating material plate, and 39 denotes a metal plate. The movable die 14 is attached to the movable die plate 13 through the three stacked plates 37, 38, 39. It is attached. The heat insulating material plate 38 raises the mold temperature in order to improve transferability when forming a thin disk, so that the high temperature of the mold is transmitted to the movable die plate 13 and the heat efficiency is not lost. 13 is provided in order to prevent the parallelism from being damaged by the temperature rise of 13. The metal plate 39 on the movable side mold 14 side is formed of the same material as the movable side mold 14, and after measuring the parallelism accurately during assembly adjustment of the machine, the metal plate 39 is once removed and the metal plate 39 The mold mounting surface side is re-polished based on the measurement result. By doing so, the parallelism is obtained as accurately as possible by machining and adjusting the mechanism. In FIG. 6, the structure on the fixed mold 15 side is omitted for convenience of illustration, but the fixed mold 15 is also attached to the fixed die plate 1 through a similar three-layer plate. It has become.
[0036]
Regarding the above three-layer plate structure, the same structure is adopted in the first embodiment and the third embodiment described later.
[0037]
Next, a third embodiment of the present invention will be described. FIG. 7 is a front view of an essential part of an injection molding machine according to the third embodiment of the present invention, in which FIG. 7 is equivalent to the first embodiment of FIGS. 1 to 5 and the second embodiment of FIG. Constituent elements are denoted by the same reference numerals, and descriptions thereof are omitted to avoid duplication.
[0038]
Similarly to the second embodiment, this embodiment also performs resin injection from the lower side of the fixed mold 15, and this embodiment differs from the second embodiment in terms of the injection mechanism. The screw prep plastic type is used.
[0039]
In FIG. 7, reference numeral 40 denotes a hot runner member embedded in the intermediate plate portion 1b of the fixed die plate 1, and includes a vertical hole 40a serving as a resin passage (resin reservoir portion) and a plunger passage, and a horizontal hole 40b continuous therewith. The opening of the nozzle portion 40 c at the tip is pressed against a resin injection port provided on the bottom surface of the fixed mold 15. The hot runner member 40 is heated by a heater (not shown). Reference numeral 41 denotes a plasticizing unit for kneading and plasticizing and sending out the resin. The heating cylinder 42, the nozzle 43 attached to the tip of the heating cylinder 42, and the screw 44 arranged to rotate in the heating cylinder 42. The opening of the nozzle 43 is pressed against the resin inlet of the horizontal hole 40b of the hot runner member 40. Reference numeral 45 denotes an injection plunger disposed so as to be able to move forward and backward in the vertical hole 40 a of the hot runner member 40.
[0040]
In the present embodiment, when the injection start timing is reached, the plunger 45 that has been retracted to the injection start position is driven forward, whereby the screw 44 passes through the nozzle 43 and the horizontal hole 40b of the hot runner member 40 to form the hot runner member. The molten resin stored in the 40 vertical holes 40a is injected and filled from the lower side of the fixed mold 15 into the cavity formed by the movable mold 14 and the fixed mold 15 by the plunger 45. In this embodiment having such a configuration, the same effects as those of the second embodiment can be obtained. Moreover, since the screw pre-plastic type is used for the injection mechanism, the weighing is stable and the screw diameter can be reduced.
[0041]
In each of the above-described embodiments, four ball screw mechanisms 2 and four shaft members 11 are provided. However, the ball screw mechanism 2 and the shaft member 11 are arranged so that parallelism correction (surface correction) is possible. The present invention is applicable as long as three or more are provided.
[0042]
【The invention's effect】
As described above, according to the present invention, the parallelism between the movable side mold and the fixed side mold can be corrected as good as possible, so that a thickness accuracy of about 1 to 2 μm is required. It is possible to provide an injection molding machine capable of forming a good product of the next generation optical disc.
[Brief description of the drawings]
FIG. 1 is a front view of an essential part of an injection molding machine according to a first embodiment of the present invention in a mold open state.
FIG. 2 is a simplified view seen from the bottom side of the injection molding machine according to the first embodiment of the present invention.
FIG. 3 is a block diagram of a mold opening / closing control system of the injection molding machine according to the first embodiment of the present invention.
FIG. 4 is a front view of an essential part of the injection molding machine according to the first embodiment of the present invention in an injection filling standby state.
FIG. 5 is a fragmentary front view of a compression completed state of the injection molding machine according to the first embodiment of the present invention.
FIG. 6 is a fragmentary front view of an injection molding machine according to a second embodiment of the present invention.
FIG. 7 is a fragmentary front view of an injection molding machine according to a third embodiment of the present invention.
FIG. 8 is a simplified diagram showing a configuration of a conventional horizontal injection molding machine.
FIG. 9 is an explanatory view showing a problem of a conventional horizontal injection molding machine.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Fixed die plate 1a Lower plate part 1b Upper plate part 2 Ball screw mechanism 3 Nut part 4 Screw part 6 Pulley 7 (7A-7D) Servo motor (servo motor "A"-"D")
8 Small pulley 9 Timing belt 10 Load cell 11 Shaft member 12 Shaft holding member 13 Movable die plate 14 Movable die 15 Fixed die 20 Mold opening / closing control unit 20a Motor A control set value storage unit 20b Motor B control set value Storage unit 20c Motor C control set value storage unit 20d Motor D control set value storage units 21A to 21D Servo driver unit 30 Hot runner member 30a Vertical hole 30b Horizontal hole 30c Nozzle unit 31 Injection unit 32 Heating cylinder 33 Nozzle 34 Screw 37 Metal plate 38 Heat insulating material plate 39 Metal plate 40 Hot runner member 40a Vertical hole 40b Horizontal hole 40c Nozzle part 41 Plasticizing unit 42 Heating cylinder 43 Nozzle 44 Screw 45 Plunger

Claims (4)

It has three or more ball screw mechanisms and a plurality of servo motors that drive each ball screw mechanism independently, and each linear motion of each ball screw mechanism is transmitted to the movable die plate to attach to the movable die plate. In a vertical injection molding machine that opens and closes the mold by moving the movable mold up and down with respect to the fixed mold attached to the fixed die plate,
Of the movable side mold and the fixed side mold, one mold has a recess formed in a horizontal plane facing the other mold, and the other mold has the one mold and the other mold. Having a convex portion formed on the opposing horizontal plane, these pair of molds form a cavity between the bottom surface of the concave portion and the top surface of the convex portion inserted into the concave portion,
In the injection filling standby state in which the movable side mold and the fixed side mold form a cavity from the mold opening completion state, the horizontal plane of the movable side mold and the horizontal plane of the fixed side mold are separated from each other. In this injection filling standby state, each ball screw mechanism is controlled so as to correct the parallelism between the movable side mold and the fixed side mold ,
The injection is performed by driving the movable mold after the injection filling, and the horizontal plane of the movable mold is controlled to be separated from the horizontal plane of the fixed mold even in the compression completion state. Molding machine. In claim 1,
An injection molding machine that controls each of the ball screw mechanisms so that the resin pressing force by the movable mold is uniform in the compression process . In claim 1 ,
The fixed die plate rotatably holds the nut portion of each ball screw mechanism, and the shaft member integrated with the vertically movable screw portion screwed into the nut portion is fixed to the movable die plate, respectively. An injection molding machine characterized in that an intermediate portion of each shaft member is splined to a shaft holding member fixed to the fixed die plate . In claim 1,
An injection molding machine for performing injection filling of resin from the lower side of the fixed side mold.

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