JP3154389B2 - Injection press molding method and injection molding apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention holds a mold with a predetermined gap opened, fills a mold cavity with a molten resin, closes the gap with a mold clamping device after the filling is completed, and compresses the mold. And an injection molding apparatus.

[0002]

2. Description of the Related Art Injection press molding using an injection molding apparatus having a mold clamping mechanism for clamping with a hydraulic mold clamping cylinder, the following various methods have conventionally been employed. (1) A stopper or the like is provided in the mold clamping mechanism, and the mold is mechanically locked by the stopper at a predetermined mold opening position. The mold compression process after injection filling is performed by releasing the mechanical lock by the stopper. Alternatively, the compression step is performed by using a separately provided compression-clamping cylinder or the like. (2) A unit dedicated to compression is mounted between the movable platen and the fixed platen of the mold clamping mechanism, and the unit is provided with a die opening holding and compression process. (3) The position of the movable platen or the movable mold is detected, and in the injection filling step, the mold clamping pressure or the injection speed is controlled so that the set mold opening amount and mold opening speed are obtained. In the compression step, the mold clamping speed or the mold clamping pressure is changed so as to achieve the set compression movement amount and compression movement speed. In this way, control is simultaneously performed using the mold clamping mechanism and the injection mechanism based on the mold opening amount set value.

[0003]

However, such a conventional method has the following problems. (1) Since it is difficult to cope with a change in molding conditions such as a resin temperature during molding, the quality of a molded product varies, and a good product cannot be supplied stably. In addition, since a time lag occurs during the transition from the injection filling to the compression step, the resin flow behavior in the mold becomes discontinuous, and as a result, defects such as flow marks occur. In this case, a control method (injection / clamp interlocking control) for simultaneously operating the injection filling step and the compression step at a certain timing is necessary, but the mechanical locking means cannot be released during the injection filling step. Interlocking control is not possible and high quality molded products cannot be obtained. (2) Although the molding machine itself does not require any major remodeling, the installation of the dedicated compression unit reduces the effective dimensions in which the mold can be mounted (downsizing of the molding machine). Correspondence to molded products is limited. Further, the compression-only unit is a considerably heavy object, and when the unit is mounted, damage to the molding machine such as deformation of the molding machine, abnormal wear of the sliding portion, and an increase in the load on the drive system is large. Further, it requires connection of a drive source of the unit, connection of a control signal for obtaining operation timing with the molding machine, and the like, and operability is extremely low. (3) Since the injection / mold clamping interlocking control method simultaneously controls the injection filling operation and the mold compression operation, the above (1) and (2)
As compared with, a high quality molded product can be obtained. However, it is extremely difficult to control the timing of interlocking the mold clamping side and the injection side, and there is a possibility that the non-defective product rate is greatly reduced. As a result, both software and hardware are extremely complicated and operability is extremely difficult. Further, since it is necessary to simultaneously drive the mold clamping side and the injection side, productivity is remarkably reduced due to an unnecessary increase in the size of the molding machine accompanying an increase in the driving capability.

[0004]

Means for Solving the Problems To solve the problems described above, it is possible to avoid unnecessary productivity increase due to the enlargement of the molding machine, and to perform molding by simple control of mold opening control and injection pressure control. In order to stably supply a high-quality molded product without being affected by fluctuations in molding conditions during the process, in the present invention, in the first invention, the fixed platen, the movable platen, and the connecting plate are arranged in the axial direction of the tie bar. The half nut is mounted between the movable platen and the connecting plate, and the tie bar is provided with a screw portion or a groove to be fitted with the half nut, and the fixed platen is provided with the moving cylinder and the tie bar. A connected mold clamping cylinder is fixed, and the movable cylinder moves the movable plate toward and away from the fixed plate, and the mold clamping cylinder presses the movable plate toward the fixed plate to apply a mold clamping mechanism. Calculate the amount of shrinkage due to cooling and solidification of resin beforehand The resin amount obtained by adding the cooling solidification shrinkage amount is injected and filled into the mold cavity, and the mold is previously held at a mold opening position corresponding to the cooling solidification shrinkage amount on the mold clamping mechanism side. After the completion of the filling is detected, the mold clamping cylinder is driven to apply the mold clamping force.

[0005] In the second invention, the injection filling in the first invention is performed by one injection pressure control capable of filling from the start of the injection filling to the completion of the injection filling, and added as a cooling solidification shrinkage amount. It was decided to fill all of the amount. Further, in the third invention, in the first invention and the second invention, the movable platen is advanced in advance by the movable cylinder, and the position of the movable platen is set to the origin in a state where both dies are touched to cool and solidify the resin. The movable platen is retracted by the movable cylinder to set the mold opening position corresponding to the amount of contraction by the retracted amount of the movable platen from the origin setting position, and the half nut is fitted into the screw portion or groove portion of the tie bar. After clamping the mold with the mold clamping cylinder, and detecting that the half nut has come into contact with the movable platen, the hydraulic pressure of the mold clamping cylinder is held so as to hold the movable mold at the set retreat position. Was controlled. According to a fourth aspect, in the first to third aspects, the contact between the half nut and the movable plate is determined by detecting a position of the movable plate during the mold clamping operation and changing the set retreat position. Was decided.

Further, in the fifth invention, the first to third embodiments
In the invention, the abutment between the half nut and the movable platen is set to a point in time when the gap between the half nut and the movable platen during the mold clamping operation is detected and the gap becomes zero. Also, the sixth
The method according to the first or second aspect of the present invention is the method according to the first or second aspect, wherein the movable platen is advanced in advance with the movable cylinder, and the stroke of the movable cylinder is set to the origin in a state where both dies are touched. Is set by the retreat amount of the moving cylinder from the origin setting position, and the half nut is fitted and fixed to the screw or groove of the tie bar, and then the mold is closed by the mold clamping cylinder. After detecting that the half nut has come into contact with the movable platen by a change in the stroke of the movable cylinder, the hydraulic pressure of the mold clamping cylinder is controlled so as to hold the movable mold at the set retreat position. did.

On the other hand, in a seventh aspect based on the first aspect, the injection filling is completed when the injection driving force of the injection mechanism suddenly starts to increase, and after the injection driving force changes, mold clamping is started. I decided that. In the eighth invention, the completion of the injection filling in the first invention is defined as a point in time when the movement of the injection driving force of the injection mechanism is stopped, and the mold clamping is started after the injection driving force reaches the stop position.

The injection molding apparatus according to a ninth aspect of the present invention has a fixed platen, a movable platen and a connecting plate arranged in the axial direction of the tie bar, and has a half nut mounted between the movable platen and the connecting plate. The tie bar is provided with a screw portion or a groove for fitting with the half nut, and the fixed plate is connected to a moving cylinder for moving the movable plate in the direction of the fixed plate and a tie bar and the movable plate is fixed to the fixed plate. A mold clamping mechanism fixedly provided with a mold clamping cylinder for applying a mold clamping force by pressing the mold, the injection filling amount setting section, the injection pressure setting section, and the injection based on the set values of the two setting sections. Equipped with an injection control unit that performs filling,
A mold opening amount setting unit for setting a mold opening amount, a position detecting unit for detecting the position of the movable platen, an origin setting unit for setting the origin of the position of the movable platen in a state where both dies are touched, and the mold clamping mechanism Mold clamping reference detecting unit that detects the contact between the half nut of
A mold clamping control unit that controls mold clamping based on set values of the mold opening amount setting unit and the origin setting unit and detection signals of the position detection unit and the mold clamping reference detection unit; An injection / fill completion detector that generates an injection / fill completion signal when the force starts to rise sharply or when the movement of the injection drive unit stops; and the mold clamping based on the detection signal from the injection / fill completion detector. The configuration includes a comparison control unit that generates a mold clamping start signal to the control unit.

Further, the injection press molding apparatus of the tenth invention has a fixed platen, a movable platen and a connecting plate arranged in the axial direction of the tie bar, and has a half nut mounted between the movable platen and the connecting plate. The tie bar is provided with a screw portion or a groove to be fitted with the half nut, and the fixed plate is connected to a moving cylinder for moving the movable plate in the direction of the fixed plate and a tie bar and the movable plate is fixed to the fixed plate. A mold clamping mechanism in which a mold clamping cylinder for pressing the mold side to apply a mold clamping force is fixedly provided, a mold opening amount setting unit for setting a mold opening amount, and a stroke detecting unit for detecting a stroke of the moving cylinder. An origin setting unit that sets the stroke position of the moving cylinder when the two molds are touched, a mold clamping reference detecting unit that detects contact between the half nut of the mold clamping mechanism and the movable platen, and the mold opening amount. Setting section and origin setting section Controlling the mold clamping on the basis of the detection signal of the the value stroke detecting section and clamping the reference detecting portion
A configuration having a mold clamping control unit was adopted .

[0010]

[Function] By filling the resin amount to which the amount of cooling solidification shrinkage is added, and by holding the mold at the mold opening position corresponding to the amount of cooling solidification shrinkage, the resin is filled into the mold when the injection filling is completed. Is almost fully filled (just-packed), and therefore is not affected at all by the occurrence of defects such as flow marks due to the discontinuity of the resin flow velocity in the mold. As a result, in the compression step, the mold clamping pressure can be increased after detecting the completion of the injection filling, so that complicated and advanced timing control of the conventional pressure increase switching is not required, and the injection side is not required. The molding machine does not need to be upsized because the interlock between the mold and the mold clamping side is avoided. In addition, during the injection filling step, the filling pressure is controlled so that the resin flow resistance in the mold cavity is small at the initial stage of filling, so that high-speed filling is performed. Because of natural deceleration, an ideal natural filling flow (natural flow) that automatically has a continuous velocity gradient and does not generate pack pressure during resin filling is achieved. As a result, the operability of injection filling control is improved. It becomes very easy.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below in detail with reference to the drawings. 1 to 8 relate to the present invention, FIG. 1 is an overall configuration diagram of an injection molding device, FIG. 2 is a plan view of a mold clamping device, FIG. 3 is a sectional view of a screw engagement adjusting device, and FIG. FIG. 5 is a flowchart showing an initial condition setting procedure in mold clamping control, FIG. 6 is a flowchart showing a molding operation procedure of an injection press molding method, FIG. 7 is an explanatory view of injection filling completion detection, FIG. FIG. 7 is an overall configuration diagram of an injection molding apparatus showing another embodiment.

As shown in FIG. 1, an injection molding apparatus 100 according to the present invention comprises a mold clamping device 1, an injection device 40, and a control device 60. As shown in FIGS. 2 to 4, the mold clamping device 1 includes a moving cylinder 2, a mold clamping cylinder 3, a tie bar 7, a fixed platen 10, a screw engagement adjusting device 11, a movable platen 20,
It is composed of a nut box 21, a half nut 22, a tie bar locking device 26, a fixed mold 30a, a movable mold 30b, a connecting plate 50, and the like. The fixed mold 30a is attached to a fixed platen 10 fixed to the upper surface of one end of the machine base 1a, while the movable mold facing the fixed plate 10 is fixed to the upper surface of the other end of the machine base 1a. 30 b is attached to the movable platen 20. The opposing surfaces of the fixed mold 30a and the movable mold 30b are configured to engage with irregularities, and define a cavity 28 between the fixed mold 30a and the movable mold 30b. The distal end of the piston rod 6 of the movable cylinder 2 fixed to both sides of the fixed platen 10 is
0, the movable platen 20 can slide on the machine base 1a with respect to the fixed platen 10 to move back and forth.

The tie bar 7 penetrating the movable platen 20
A plurality of pieces having the same overall length (4 in the present invention)
One end is fixed to the internal piston 5 of the mold clamping cylinder 3, and the other end is penetrated in a direction substantially perpendicular to the connection plate 50, and then is fixed by tightening with a nut or an end plate 51. At the same time, the tie bar 7 and the connecting plate 50 are prevented from turning around by using a key or the like.

An inner piston 5 is provided in the mold clamping cylinder 3 so as to be slidable back and forth, and a packing for preventing oil leakage is provided on the outer periphery of the inner piston 5. A tie bar 7 is provided on the rod side of the inner piston 5. The ram 53 is fixed on the head side.
Is fixed on substantially the center of the internal piston 5 and is provided in a convex shape.
Further, the ram cylinder 52 engaged with the ram 53 is
3 is provided so as to be slidable back and forth, and packing is provided on a sliding portion on the outer periphery of the ram 53 so that oil from the ram chamber 5c does not flow to the piston head chamber side 5b.
Reference numeral 5a indicates the piston rod chamber side.

The outer diameter of the ram 53 is, for example, 1/2 or less of the outer diameter of the tie bar 7 or 1/1 / the outer diameter of the internal piston 5.
The length of the ram 53 is set to 3〜 or less, and the length of the ram 53 is such that the front end of the ram 53 abuts on the inner part of the ram cylinder 52 before the head end surface of the internal piston 5 abuts on the end surface of the ram cylinder 52 during mold clamping. It has such a configuration.

At the substantially middle position of the tie bar 7, when the movable mold 30b and the fixed mold 30a come into contact with each other during the mold closing operation, the movable plate 20 meshes with a half nut 22 described later to move the movable plate 20 to the tie bar 7.
A screw portion or a groove portion 8 is formed to be locked to the head. One end is fixed to the movable platen 20, and the other end is screwed with the screw portion 12 of the adjusting shaft 13 of the screw engagement adjusting device 11, which will be described later. here,
The screw engagement adjusting device 11 includes a screw portion 12, an adjustment shaft 13, a pressing member 17, a slide key 18, a sprocket 19, a holding plate 25, and the like.

Next, the tie bar locking device 26 is shown in FIGS.
This will be described with reference to FIG. The tie bar locking device 26 includes a half nut opening / closing cylinder 14, a piston 15, a piston rod 16, a half nut 22, a connecting rod 101, a stopper 10
2, 103.

The half nut 22 is provided adjacent to the movable platen 20 and has a set of half nuts 22 each of which is divided into upper and lower portions for each tie bar 7. One end of the piston rod 16 is fixed to the end face. Further, the other end of the piston rod 16 engages with the half nut opening / closing cylinder 14 and slides up and down.
5 is provided, and an adjusting plate 104 is fixed to the lower end of the half nut opening / closing cylinder 14. A connecting rod 101 connected through the half nuts 22a and 22b is disposed on the left and right sides of the piston rod 16, one end of the connecting rod 101 is fixed to the adjusting plate 104, and the other end is connected to the half nut 22b. It is fixed.

As shown in FIG. 4 (a), the half nut opening / closing cylinder 14 has a piston rod chamber side 15
By supplying the pressure oil to b, the piston 15 is pushed up and the half nut opening / closing cylinder 14 is pushed down, so that a pair of upper and lower half nuts 22 a and 22 b move while sliding on the nut box 21. And split nut 2
The meshing state between the tie bar 2 and the tie bar 7 is released, and the tie bar 7 stops when it comes into contact with the stoppers 102 and 103, respectively.

When it is desired to engage the half nut 22 with the tie bar 7, pressure oil is supplied to the piston head chamber side 15a of the half nut opening / closing cylinder 14, as shown in FIG. , The piston 15 is pushed down and the half nut opening / closing cylinder 14 is pushed upward, so that the half nuts 22a and 22b
1 is slidably moved and finally comes into contact with the tie bar 7 to be engaged.

Further, in the right and left directions of the half nut 22 described above, one end of the half nut 22 has a sprocket portion 19 fixed to the end of the adjustment shaft 13 provided with the tie bar 7 inserted therethrough. By turning, the end of the adjustment shaft 13 on the side opposite to the sprocket portion 19 always comes into contact with the half nut 22 and slides.

At the other end of the split nut 22, several insertion chambers for the pressing member 17 are provided in a part of the movable platen 20 on the side opposite to the fixed platen 10 for each set of two split nuts 22. The half nut 22 is constantly pressed in the axial direction of the tie bar 7. When the adjustment shaft 13 moves to the fixed platen 10 side, the spring of the pressing member 17 is compressed, and the anti-fixed platen 10 side is pressed. It is arranged to be stretched when moving to.

The adjustment shaft 13 has a sprocket portion 19 on the outer periphery near the end on the side opposite to the half nut 22, and is prevented from rotating with the adjustment shaft 13 by using a slide key 18. The sprocket portion 19 is connected with a chain (not shown), and the chain is connected with a sprocket integral with the output shaft of a motor (not shown). The rotation of the motor drives the chain to move the adjustment shaft 13 back and forth in the axial direction of the tie bar 7. As a result, the half nut 2
The position of the half nut 22 can be adjusted so that the nut 2 engages with the thread portion or the groove portion 8 on the tie bar 7.

As for the outer periphery of the shaft of the sprocket 19, one end is fixed to the end of the nut box 21 and the other end is fixed to the nut box 21 to prevent the sprocket 19 from falling off. The holding plate 25 is rotatably supported by the holding plate 25. Reference numeral 24 indicates an insertion hole.

In this embodiment, the above-described mold clamping device is used for the following reason. (1) The mold clamping mechanism is compact and space can be saved. (2) Since the amount of pressurized oil supplied to the small-capacity ram chamber 5c may be small, the mold opening and compression responsiveness during injection compression molding are high. (3) The tilt correction of the movable platen 20 (leveling control) can be performed by adjusting the hydraulic pressure supplied to the plurality (four) of the mold clamping cylinders 3.

Next, the injection device 40 will be described. In this embodiment, the injection device 40 includes a screw 4 in a barrel 41.
2 is provided, and the resin material in the hopper 43 is supplied to the supply zone,
It is configured to be heated and compressed in a compression zone, melt metered in a metering zone, and injected into a nozzle 44 via an injection zone.

A heater for externally heating the resin material is provided on the outer peripheral surface of the barrel 41, and the resin material is sent forward by the rotation of the screw 42.

Reference numeral 46 denotes an injection cylinder, and 47 denotes a forward / reverse rotation motor, which is directly connected to the screw 42 and rotates the screw 42 forward / reverse.

Next, the control device 60 will be described. The control device 60, as shown in FIG.
1. Injection pressure setting unit 62, injection control unit 63, hydraulic control valve 64, mold clamping control unit 66, hydraulic control valve 67, hydraulic supply source 6.
8a, 68b, injection filling completion detecting section 69, timer 70,
Time setting unit 71, comparison control unit 72, mold opening amount setting unit 73,
An origin setting unit 74, a position detection unit 75, and a mold clamping reference detection unit 76 are provided.

The injection filling amount setting section 61 and the injection pressure setting section 6
2 is connected to the injection control unit 63, and the injection control unit 63 is connected to a hydraulic control valve 64 for controlling the operation of the injection cylinder 46 and a control device (not shown) for controlling the operation of the forward / reverse rotation motor 47, respectively.

The mold clamping control section 72 is connected to a mold opening amount setting section 73, and is also connected to a comparison control section 72 and a hydraulic control valve 67. The comparison setting section 72 includes an injection control section 63, a time setting section 71, and a timer. Injection filling completion detection unit 6 via 70
9 is also connected. The injection filling completion detecting section 69 detects the oil pressure of the injection cylinder 46. 68a and 68b indicate simplified hydraulic supply sources.

On the other hand, the mold opening amount setting unit 73 is connected to the mold clamping reference detecting unit 76 and the origin setting unit 74, and receives a detection signal from a position sensor incorporated in the movable platen 20. Is also connected to the mold clamping reference detecting unit 76.

The injection molding apparatus 10 configured as described above
The operation of 0 will be described. FIG. 5 shows a procedure for setting initial conditions for mold clamping control. Initial conditions are set according to the following procedure. (1) The movable platen 20 is fixed to the fixed platen 1
Move to 0 side and advance. After the two dies 30a and 30b touch, the driving of the moving cylinder 2 is stopped,
The position detection unit 75 detects the position of the movable platen 20 and stores it as the mold touch point S ₀ in the origin setting unit 74. (2) Simultaneously, the amount of resin obtained by adding the cooling solidification shrinkage of the resin calculated in consideration of the resin physical properties to the volume of the cavity 28 defined by the fixed platen 10 and the movable platen 20 set by the injection filling amount setting unit 61. against the weighing, backward movement of the movable mold 30b of the separation of the movable mold 30b corresponding to the cooling and solidification shrinkage of the fixed mold 30a from the mold touch point S _0, i.e. mold opening amount set value S is set by the mold opening amount setting unit 73. In this way, when the injection filling is completed, the resin in the mold cavity 28 is almost fully filled (just pack), so that the flow mark or the like due to the discontinuity of the resin flow velocity in the mold cavity 28 is formed. No defect is generated.
As a result, after the completion of the injection filling is detected, it is possible to shift to the compression step by increasing the clamping pressure, so that the disadvantage of simultaneous control of the injection side and the clamping side can be eliminated. (3) The movable platen 20 is moved backward by the movable cylinder 2 based on the mold opening amount set value S, and after the position detection unit 75 confirms that the mold opening amount set value S is reached, the movable cylinder 2 is driven. Is stopped and the initial setting of the mold clamping control in the mold opening setting is completed. The above initial setting operation is performed before production molding.
It may be performed once in advance.

Next, the molding operation in the injection press molding method is sequentially performed by the following procedure as shown in FIG. (1) The mold opening set value S previously set by the mold opening setting unit 73
, The movable platen 20 is moved forward to the fixed platen 10 side by the moving cylinder. When the signal of the position detection unit 75 matches the set value S, the moving cylinder 2 is stopped. (2) By driving the half nut opening / closing cylinder 26a,
The half nut 22 and the screw or groove on the tie bar 11 are completely engaged and fixed. Here, both molds 3
From the mold thickness (die height value) of 0a and 30b and the pitch of the threaded portion or the groove portion, the half nut 22 and the tie bar 11 are determined.
The sprocket is rotated by rotating a motor connected by a chain in advance so that the upper screw portion or the groove portion is completely meshed, and the forward and backward movement amount of the adjustment shaft is adjusted. (3) The mold clamping control unit 66 controls the hydraulic control valve 67 to supply pressure oil to the mold clamping cylinder 3 to perform the mold clamping operation, and the mold clamping reference detecting unit 76 performs the half nut 22 and the movable platen 2.
Monitoring of contact detection of 0 is started. That is, the half nut 22 is engaged with the thread or groove on the tie bar 11.
At the time of fixing, the half nut 22 and the movable platen 20 are set to have a gap calculated from the die height value and the pitch of the screw portion or the groove portion so that the drive of the half nut 22 is facilitated. Therefore, the mold clamping operation in this case means that the movable platen position is mainly kept as it is, and the tie bar 11 and the half nut 22 meshed and fixed to the tie bar 11 are slid forward so as to be pulled out toward the fixed platen 10 side. I do. (4) The contact between the half nut 22 and the movable platen 20 is detected by any of the following methods. This is performed by detecting the gap between the half nut 22 and the movable platen 20. In this case, the contact between the half nut 22 and the movable platen 20 can be defined as “the gap is zero” (direct detection method). This is performed by detecting the amount of fluctuation of the movable platen 20. In this case, when the half nut 22 and the movable platen 20 come into contact with each other, the movable platen 20 can be integrally identified to indicate a forward movement for mold clamping (indirect detection method). Note that this method can be said to be the most reliable method since it is direct detection. In the other method, the sensor can be shared with the position detection unit 75 of the movable platen 20, so that the system can be simplified.

(5) After the mold clamping reference detecting section 76 detects the contact between the half nut 22 and the movable platen 20, the mold opening amount set value S set previously is held, that is, the movable platen 20 is held. The injection filling process is started at the same time as the hydraulic control of the mold clamping cylinder 3 (the mold clamping position holding control) is performed so as to hold the position. By doing so, high-precision mold opening amount control can be performed, and after the mold-opening mold-clamping operation, the injection operation can be started without delay. Since the operation can be omitted, the cycle can be shortened. (6) In the injection filling step, the measured value of the resin amount obtained by adding the cooling solidification shrinkage amount of the resin calculated according to the resin properties to the cavity volume set by the injection filling amount setting unit and the cavity set by the injection pressure setting unit The injection is performed based on the injection pressure value of one pressure (constant pressure) of the injection pressure condition with the best injection efficiency from the injection filling pressure range in which the inside can be filled and no burrs are generated. As a result, in the early stage of the injection, the flow resistance in the cavity is small, so that the filling is performed at a high speed. In the latter stage of the injection, the filling speed is naturally reduced due to the increase in the flow resistance in the cavity, and as a result, there is a continuous speed gradient. In addition, an ideal natural filling flow (natural flow) that does not generate a pack pressure can be easily obtained. Further, during the injection filling step, the injection is controlled to a so-called cut-off state without leaving a cushion amount until the screw reaches the forward limit by pressure control of the injection cylinder. As a result, it is possible to extremely easily and accurately detect the completion of the injection filling. This state will be described with reference to FIG.

(7) From the start of injection filling (point S) to the completion of injection filling (point E), the operating oil pressure in the injection cylinder is adjusted together with the screw advance operation (injection speed) so that the injection filling pressure is constant. Is controlled to be constant. When injection is completed (E
Point), that is, when the screw reaches the forward limit, the forward movement of the screw is stopped (injection speed = 0), so that the working oil pressure value in the injection cylinder 46 temporarily rises sharply. Therefore, the injection filling completion can be accurately detected by any method of detecting the operating oil pressure value in the injection cylinder 46 or detecting the forward movement (injection speed) of the screw 42 or the piston 48. (8) Based on the detection signal of the injection filling completion detection unit 69,
The comparison control unit 72 transmits a mold-clamping start signal to the mold-clamping control unit 66 to start the compression process and activates the timer 70. In this case, since the resin in the mold cavity 28 is in a just-packed state, no defect such as a flow mark is generated even if the compression step is started simultaneously with the completion of the injection filling. Also, even in the shot-off state, the nozzle 44
Since the molten resin is filled in the inside and the passage to the cavity 28 while maintaining the set pressure value, there is almost no backflow of the resin in the compression step.

(9) The following setting values are input to the time setting section 71 in advance, and the comparison control section 72 determines the time-out signal of the timer 70 and the setting value of the time setting section 71, and determines whether the Of the mold and control of the injection side. Here, the pressure-holding cooling time (compression completion time) t ₁ and the metering start time t ₂ is set as follows. That is, the holding pressure cooling time t ₁ is set by calculating the cooling solidification time of the resin based on the resin temperature, the mold cooling capacity, the shape of the molded product, and the like. Further, the weighing start time t ₂ is set based on the gate sealing time, and based on the shut-off valve closing operation completion time in a molding machine having a shut-off valve incorporated therein. (10) The comparison control unit 7 receives a time-out (t ₂ ) signal.
2 transmits a measurement start signal to the injection control unit 63 to start the measurement operation. Similarly, in response to the time-out (t ₁ ) signal, the comparison control unit 72 sends a compression completion signal to the mold clamping control unit 66, removes the product after the mold opening operation, and starts the next molding operation.

FIG. 8 shows an injection molding apparatus 100A showing another embodiment (Embodiment 2) of the present invention. Only points different from the injection molding apparatus 100 of FIG.
Instead of detecting the stroke position, the stroke position of the movable cylinder 2 is detected to perform the mold opening setting and the detection of the movable platen and the half-split nut 22, and the stroke detection unit 75A is used instead of the position detection unit 75. It is a point provided. The sixth invention in the present invention is carried out in the injection molding apparatus 100A of the second embodiment.

The initial condition of the mold clamping control in the second embodiment.
The case setting procedure is as follows. (1) The movable platen 20 is moved forward by the moving cylinder 2 and
After the touch of 30a, 30b, the moving cylinder 2 is driven.
Is stopped and moved by the stroke detection unit 75A.
Detects cylinder stroke and detects mold touch point S₀As
The origin is set by the origin setting unit 74. (2) At the same time, a mold opening equivalent to the amount of resin solidification shrinkage due to cooling
Set point S to mold touch point S ₀Of moving cylinder 2 from
Stroke amount, that is, mold opening amount as the amount of separation between both molds
The setting is performed by the setting unit 73. (3) The movable platen 20 is moved backward by the movable cylinder 2,
That the retraction stroke of the Linda 2 has reached the set value S
After the stroke is detected by the stroke detector 75A, the moving cylinder 2
Of the mold closing control in the mold opening setting.
Finish the period setting. In this way, the mold opening is directly set.
Control is performed with the detection signal of the dynamic cylinder stroke
As a result, it is possible to set the mold opening
Because the moving parts and sensors are shared, the control system
The system can be further simplified.

On the other hand, the molding operation procedure of the second embodiment is performed as follows. (1) The movable cylinder 20 is advanced by the movable cylinder 2 based on the mold opening amount setting value S set by the mold opening amount setting section 73. After the stroke detecting section 75A detects that the moving cylinder stroke has reached the set value S, the driving of the moving cylinder 2 is stopped. (2) The half-split nut opening / closing cylinder 26 is driven so that the half-split nut 22 and the thread or groove on the tie bar 7 are completely engaged and fixed. Also in this case, similarly to the first embodiment (the injection molding apparatus 100 in FIG. 1), the position where the half nut 22 and the screw portion or the groove portion on the tie bar 7 are completely meshed is adjusted in advance. (3) The mold clamping control unit 66 controls the hydraulic control valve 67 to supply pressurized oil to the mold clamping cylinder 3 to perform the mold clamping operation, and the mold clamping reference detecting unit 76 performs the half nut 22 and the movable platen 2.
0 contact detection is performed. Half nut 22 and movable platen 20
Is detected by contact between the half nut 22 and the movable platen 20 during the mold clamping operation, thereby causing the movable platen 20 to integrally move to perform a forward movement for mold clamping. Utilizing the fact that the connected moving cylinder stroke changes, the stroke detection unit 75A detects the change amount of the moving cylinder stroke. (4) After detecting the contact between the half nut 22 and the movable platen 20 by the mold clamping reference detecting unit 76, the mold clamping amount is set so that the mold opening set value S previously set, that is, the moving cylinder stroke position does not change. The position holding control is performed by controlling the hydraulic pressure of the cylinder 3 and the injection filling process is started. Thus, the mold opening amount setting control, the half-split nut 22 and the movable platen 20
In the series of mold clamping control of the contact detection of the mold (which also has two roles of the start of the mold clamping position holding control and the start of the injection filling process) and the series of mold clamping control of the mold clamping position holding control, control is performed by one detection signal of the moving cylinder stroke. By doing so, the control system can be simplified and operability can be improved.

[0041]

As described above, in the present invention, the following excellent effects can be exhibited. (1) By injecting and filling the resin amount obtained by adding the cooling solidification shrinkage amount of the resin and setting the mold opening amount corresponding to the cooling solidification shrinkage amount, the molten resin remains in a just-packed state even when the injection filling is completed. As a result, there is no occurrence of defects such as flow marks due to the discontinuity of the resin flow, and as a result, the injection / mold clamping interlocking control that overlaps the compression process with the injection filling process becomes unnecessary. In addition, the productivity is improved because the size of the molding machine for the interlocking control can be prevented from being unnecessarily large, and the productivity is improved. (2) Ideal injection filling control that has a continuous speed gradient according to the product shape by using one injection pressure that can be filled, does not generate pack pressure, and enables short-time filling. Can be automatically set very easily, so that control operability is extremely easy. (3) Injection filling control is performed by injection pressure control, and by filling without leaving a cushion amount, the injection filling completion detection can be easily and accurately detected, and the mold clamping pressure increase start control can be easily performed. The control of the compression step and the start of metering after the completion of the injection filling can be performed by simple control using a timer, and a high-quality molded product can be obtained by an extremely easy operation. (4) The mold opening / closing operation of the mold is performed by a movable cylinder, and injection press molding is performed by using a molding machine that performs high-pressure mold clamping with a mold clamping cylinder connected to a tie bar. The holding control of the mold clamping is controlled by the hydraulic control of the small-capacity, short-stroke clamping cylinder, and the response delay due to the compression of the hydraulic oil is extremely small. It is possible to stably supply extremely high quality molded products. Furthermore, by controlling a plurality of mold clamping cylinders independently, leveling control for correcting the inclination of the mold during the molding operation, and conversely, it is possible to apply a compression action while giving an arbitrary tilt, Since the mold clamping operation can be performed according to the product shape, an injection press molding machine having a wide range of application can be supplied.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an injection molding apparatus according to an embodiment (Embodiment 1) of the present invention.

FIG. 2 is a plan view of the mold clamping device according to the embodiment of the present invention.

FIG. 3 is a cross-sectional view of the screw engagement adjusting device according to the embodiment of the present invention.

FIG. 4 is an explanatory view showing an operation state of the half nut according to the embodiment of the present invention.

FIG. 5 is a flowchart showing an initial condition setting procedure in the mold clamping device according to the embodiment of the present invention.

FIG. 6 is a flowchart showing a molding operation procedure of the injection press molding method according to the embodiment of the present invention.

FIG. 7 is an explanatory diagram of injection filling completion detection according to the embodiment of the present invention.

FIG. 8 is an overall configuration diagram of an injection molding apparatus according to another embodiment (Example 2) of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Mold clamping device 1a Base 2 Moving cylinder 3 Mold clamping cylinder 4, 5 Internal piston 4a, 5a Piston rod chamber side 4b, 5b Piston head chamber side 5c Ram chamber 7 Tie bar 8 Screw portion or groove portion 10 Fixed platen 11 Screw meshing adjusting device 14 Half nut opening / closing cylinder 17 Pressing member 20 Movable platen 22 (22a, 22b) Half nut 24 Insertion hole 26 Tie bar locking device 28 Cavity 30a Fixed die 30b Movable die 40 Injection device 41 Barrel 42 Screw 44 Nozzle 46 Injection Cylinder 47 Forward / reverse rotation motor 48 Piston 50 Connecting plate 51 End plate 52 Ram cylinder 53 Ram 60 Controller 61 Injection filling amount setting unit 62 Injection pressure setting unit 63 Injection control unit 64 Hydraulic control valve 66 Mold clamping control unit 67 Hydraulic control valve 68a, 68b Hydraulic supply Supply source 69 Injection and filling completion detection unit 70 Timer 71 Time setting unit 72 Comparison control unit 73 Mold opening setting unit 74 Origin setting unit 75 Position detection unit 75A Stroke detection unit 76 Mold clamping reference detection unit 100 Injection molding device 100A Injection molding device 101 Connecting rod 102, 103 Stopper 104 Adjustment plate S Mold opening set value S ₀ Mold touch point t ₁ Holding pressure cooling time (compression completion time) t ₂ Measurement start time

Claims (10)

(57) [Claims] 1. A fixed plate, a movable plate and a connecting plate are arranged in the axial direction of a tie bar, a half nut is mounted between the movable plate and the connecting plate, and the tie bar is fitted with the half nut. The fixed plate is fixed with a moving cylinder and a mold clamping cylinder connected to the tie bar.The moving cylinder moves the movable plate toward and away from the fixed plate, and the movable plate moves with the mold clamping cylinder. Using a mold clamping mechanism that applies a mold clamping force by pressing the plate toward the fixed platen, calculate the amount of cooling, solidification, and shrinkage of the resin in advance, and inject the amount of resin that has been added to the amount of cooling, solidification, and shrinkage into the mold cavity. In addition to filling, the mold clamping mechanism previously holds the mold at a mold opening position corresponding to the cooling, solidifying and shrinking amount, and after detecting the completion of injection filling, drives the mold clamping cylinder to mold clamping force. Specially to load Injection press molding method to be. 2. The injection filling according to claim 1 is performed by one injection pressure control capable of filling from the start of the injection filling to the completion of the injection filling, and the entire amount of the resin added as the cooling solidification shrinkage is filled. The injection press molding method according to claim 1, wherein 3. The movable platen is advanced by a movable cylinder in advance, and the position of the movable platen is set to an origin in a state where both dies are touched, and the movable position of the mold opening amount corresponding to the amount of cooling, solidification and contraction of the resin is movable by the movable cylinder. By setting the movable plate from the retreat amount from the origin setting position by retracting the plate, the half nut is fitted and fixed to the screw portion or groove portion of the tie bar, and then the mold is clamped by the mold clamping cylinder. 3. The injection according to claim 1, wherein after detecting that the half nut has contacted the movable platen, the hydraulic pressure of the mold clamping cylinder is controlled so as to hold the movable mold at the set retreat position. Press molding method. 4. The abutment between the half nut and the movable platen at a point in time when the position of the movable platen is detected during the mold clamping operation and the set retreat position fluctuates. The injection press molding method according to claim 2 or 3. 5. The abutment between the half nut and the movable platen is set to a point in time when a gap between the half nut and the movable platen during a mold clamping operation is detected and the gap becomes zero. Claim 1
The injection press molding method according to claim 2 or claim 3. 6. A movable cylinder is advanced by a movable cylinder in advance, and the stroke of the movable cylinder is set to an origin in a state where both molds are touched, and a mold opening position corresponding to a cooling solidification contraction amount of the resin is set to the origin setting position. After setting by the amount of retraction of the stroke of the moving cylinder from, the half nut is fitted and fixed to the thread or groove of the tie bar,
After clamping the mold with the mold clamping cylinder and detecting that the half nut has come into contact with the movable platen by the change in the stroke of the moving cylinder, the hydraulic pressure of the mold clamping cylinder is held so as to hold the movable mold at the set retreat position. The injection press molding method according to claim 1 or 2, wherein the method is controlled. 7. The injection press according to claim 1, wherein the injection filling is completed when the injection driving force of the injection mechanism starts to rise sharply, and the mold clamping is started after the change of the injection driving force. Molding method. 8. The method according to claim 1, wherein the injection filling is completed when the movement of the injection driving force of the injection mechanism is stopped, and the mold clamping is started after the injection driving force reaches the stop position. Injection press molding method. 9. A fixed platen, a movable platen and a connecting plate are arranged in the axial direction of the tie bar, and have a half nut mounted between the movable platen and the connecting plate. The fixed platen is connected with a moving cylinder and a tie bar for moving the movable platen toward and away from the fixed platen, and the movable platen is pressed against the fixed platen to apply a mold clamping force to the fixed platen. A mold clamping mechanism having a mold clamping cylinder fixedly provided, an injection filling amount setting unit, an injection pressure setting unit, and an injection control unit for performing injection filling based on set values of the two setting units; A mold opening amount setting unit for setting the opening amount, a position detection unit for detecting the position of the movable platen, an origin setting unit for setting the origin of the position of the movable platen in a state where both dies are touched, and an origin setting unit for the mold clamping mechanism. A mold clamping reference detector that detects the contact between the half nut and the movable platen
A mold clamping control unit that controls mold clamping based on setting values of the mold opening amount setting unit and the origin setting unit and detection signals of the position detecting unit and the mold clamping reference detecting unit; An injection / fill completion detector that generates an injection / fill completion signal when the force starts to rise sharply or when the movement of the injection drive unit stops; and the mold clamping based on the detection signal from the injection / fill completion detector. An injection molding apparatus having a comparison control unit that generates a mold clamping start signal to a control unit. 10. A fixed platen, a movable platen and a connecting plate are arranged in the axial direction of the tie bar, and have a half nut mounted between the movable platen and the connecting plate. The fixed platen is connected with a moving cylinder and a tie bar for moving the movable platen toward and away from the fixed platen, and the movable platen is pressed against the fixed platen to apply a mold clamping force to the fixed platen. Equipped with a mold clamping mechanism in which a mold clamping cylinder is fixedly installed, a mold opening amount setting unit that sets the mold opening amount, a stroke detection unit that detects the stroke of the moving cylinder, and a moving cylinder with both molds touching. An origin setting unit that sets the stroke position of the origin, a mold clamping reference detecting unit that detects the contact between the half nut of the mold clamping mechanism and the movable platen, and a setting value of the mold opening amount setting unit and the origin setting unit, and Stroke detector and mold clamping standard An injection molding apparatus comprising: a mold clamping control unit that controls mold clamping based on a detection signal of a detection unit.