JP2000211001A - Method for injection press molding and injection press molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably produce a product with good transfer property by a method wherein pressure of a resin material is detected and a mold clamping force for a fixed mold and a movable mold is controlled so as to make the detected pressure value to be a target value when the resin material is fed by injection into a molding cavity. SOLUTION: When injection press molding is performed, at first, in a mold clamping device 16, a movable platen 30 is moved and brought close to a fixed platen 24 to register the fixed mold 12 and the movable mold 14. In addition, in an injection device 22, a molten resin material 20 is fed into a molding cavity 18. Thereafter, the movable platen 30 and the fixed platen 24 are clamped by a hydraulic cylinder mechanism 35 for clamping to obtain a product. During this molding, a pressure sensor 66 for detecting pressure in a dumpling part 64 existing in the neighborhood of a connecting part of a runner part is provided and mold clamping pressure of the molds 12 and 14 is controlled by controlling feeding and discharging of a hydraulic oil to the hydraulic cylinder mechanism 35 for clamping by means of a cylinder mechanism control device 70 so as to make the detected value of the pressure of the dumpling part 64 to the target value of the pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method of applying a press pressure to a fixed mold and a movable mold after injecting and supplying a resin material into a molding cavity formed by combining a fixed mold and a movable mold. TECHNICAL FIELD The present invention relates to an injection press molding method and an injection press molding machine for obtaining a product to be manufactured.

[0002]

BACKGROUND ART Conventionally, as one of resin molding methods,
Injection press molding is known in which a resin material is injected and supplied into a molding cavity formed by combining a fixed mold and a movable mold, and then a press pressure is applied to the fixed mold and the movable mold. Since the internal pressure of the resin material is made uniform and the occurrence of defects such as warpage and distortion in the product is reduced, it is employed in the production of large thin resin products, for example. That is, in such a conventional injection press molding, a resin material supplied in a dango state is partially supplied to a molding cavity formed by a fixed mold and a movable mold which are positioned while being opened by a predetermined amount. Then, the fixed mold and the movable mold are clamped by press pressure, spread and filled in the whole of the molding cavity, cooled, and solidified to obtain a desired resin product.

However, in such conventional injection press molding, it is difficult to transfer information such as the shape on the inner surface (molding surface) of the molding cavity of the mold in the obtained product in a sufficiently stable manner. And in particular,
In the dumpling portion of the resin material supplied in the dumpling state to the molding cavity before the pressing pressure is applied, there is a problem that the problem of poor transfer easily occurs.

[0004]

Here, the present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to make the internal pressure of a resin material uniform so that warpage or distortion of a product can be prevented. An improved injection press molding method and injection press molding machine capable of improving the transferability of the molding surface of a product while maintaining the technical effects of conventional injection press molding that occurrence of defects is prevented. To provide.

[0005]

Therefore, in order to solve such a problem, the present inventor first performed a number of experiments and examined and found that a transfer failure in a product was caused by injection supply to a molding cavity before a press pressure action. Technical knowledge has been obtained that the major cause is that the skin layer is formed on the dumpling portion of the resin material. Such a technical finding is based on the measured transferability data shown in the following “Table 1”. In the spread portion formed by the mold clamping after the press pressure action, the transferability is improved by increasing the press pressure. However, in the part of the dumpling formed before the press pressure action, the transferability was hardly improved by increasing the press pressure, and it was recognized that the injection speed and filling time greatly affected the transferability. Inferred.

[0006]

[0007] The present invention has been completed based on the technical knowledge thus obtained, and the following describes aspects of the present invention which have been made to solve the above-mentioned problems. I do. In addition, each aspect described below can be adopted in an appropriate combination. In addition, it should be understood that aspects and technical features of the present invention are not limited to those described below, but are recognized based on the invention described in the entire specification and the drawings. is there.

According to a first aspect of the present invention, after a resin material is injected and supplied to a molding cavity formed by combining a fixed mold and a movable mold, a pressing pressure is applied to the fixed mold and the movable mold. In addition, an injection press molding method for mold clamping,
At the time of injection supply of the resin material to the molding cavity, the pressure applied to the resin material is directly or indirectly detected, and the detected pressure value of the resin material becomes a preset target value. Preferably, the mold clamping force between the fixed mold and the movable mold is adjusted.

According to the injection press molding method of the present embodiment, even before the press pressure is applied to the dumpling portion of the resin material injected and supplied to the molding cavity, the resin material is injected from the time of injection and supply to the molding cavity. , The predetermined pressure set as the target value is maintained. By this, information such as the shape of the molding surface can be advantageously transferred to the dumpling portion before the thick skin layer is formed, and a product with good transferability can be stably manufactured. It is.

Further, in the injection press molding method of this aspect, the pressure applied to the resin material injected and supplied to the molding cavity can be appropriately adjusted by adjusting the setting of the target value. By avoiding excessive pressure action on the material, it is possible to advantageously prevent the occurrence of defects such as warpage and distortion of the product.

In this embodiment, as a method for directly or indirectly detecting the pressure applied to the resin material when the resin material is injected and supplied to the molding cavity, for example, the pressure supplied into the molding cavity is A method for directly detecting the pressure of the resin material, a method for directly detecting the pressure of the resin material injected into the molding cavity, or a method for applying an injection pressure to the resin material into the molding cavity, such as an injection screw or an injection plunger. The method of indirectly detecting the pressure applied to the resin material based on the detected value of the driving force (injection pressure) is particularly preferable because high detection accuracy can be easily obtained. Other than that, for example, by using a lot of actual measurement data and calculation data as needed, based on the detected values of the clamping force of the fixed mold and the movable mold, How to indirectly detect the pressure that is exerted on the materials can also be employed.

According to a second aspect of the present invention, in the injection press molding method according to the first aspect, the target value is kept constant over the entire time of injecting and supplying the resin material to the molding cavity. That is the feature. According to this aspect, it is possible to always apply an effective pressure to the resin material injected and supplied to the molding cavity, and it is possible to further improve the transferability.

In the injection press molding method according to the first aspect, it is of course possible to change the target value over time during the time of injecting and supplying the resin material to the molding cavity. It should be understood that this makes it possible to flexibly cope with various conditions such as, for example, the heating temperature of the mold and the type of the resin material.

Still further, according to a third aspect of the present invention, in the injection press molding method according to the first or second aspect,
It is characterized in that the maximum value of the target value is set to substantially the same value as the value exerted on the resin material when a press pressure is applied after injection of the resin material into the molding cavity. According to this aspect, since substantially the same pressure as that of the spread portion is applied to the dumpling portion that is injected and supplied to the molding cavity, the transferability of the dumpling portion can be more advantageously achieved.

Further, a fourth aspect of the present invention includes a mold clamping device for forming a molding cavity by molding a fixed mold and a movable mold, and an injection device for injecting and supplying a resin material to the molding cavity. An injection press molding machine for injecting and supplying a resin material to a molding cavity by the injection device and then applying a pressing pressure to a fixed mold and a movable mold by the mold clamping device to perform molding. Detecting means for directly or indirectly detecting the pressure of the supplied resin material; target pressure setting means for setting a target value of the pressure of the resin material injected and supplied to the molding cavity; The mold clamping force in the mold clamping device is adjusted until the press pressure is applied so that the detected pressure value becomes the target value set by the target pressure setting means. That a control means is provided, it characterized.

In the injection press molding machine having such a structure according to this embodiment, even before the pressing pressure is applied, the resin injected into the molding cavity is supplied by adjusting the clamping force of the clamping device. A pressure corresponding to the target value is effectively applied to the material, so that good transferability can be realized for the entire product including the dumpling portion. In addition, since the mold clamping force in the mold clamping device is controlled according to the target value, it is possible to prevent an excessive pressure action on the resin material and to suppress the occurrence of defects such as warpage and distortion of the product.

In this embodiment, as a detecting means for directly or indirectly detecting the pressure of the resin material injected and supplied to the molding cavity, for example, the detecting means is provided in the molding cavity and supplied to the molding cavity. A cavity pressure sensor that directly detects the pressure of the resin material, a nozzle pressure sensor that is installed in the injection nozzle of the injection device and directly detects the pressure of the resin material injected into the molding cavity, or an injection screw in the injection device Using an injection pressure sensor or the like installed in a drive system such as an injection plunger or the like to detect an injection pressure is particularly preferably employed because high detection accuracy can be easily obtained. For example, by utilizing a lot of measured data and calculation data as needed, a mold clamping system that is installed in a mold clamping device and detects the mold clamping force is used. Those utilizing Nda圧 sensor or the like can also be employed.

Further, in this embodiment, the pressure applied to the resin material injected and supplied to the molding cavity is:
The major feature is that control is possible before the pressing pressure is applied, and the control form of the pressure is appropriately adjusted according to the product shape, the mold temperature, the type of the resin material, and the like. It is subject to change and is not particularly limited.

In the present invention according to any one of the first to fourth aspects, the fixed mold and the movable mold forming the molding cavity are not always required to inject and supply the resin material into the molding cavity. It is not necessary to open by a predetermined amount, and it may be closed.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to clarify the present invention more specifically, embodiments of the present invention will be described in detail with reference to the drawings.

First, FIG. 1 schematically shows a configuration of an injection press molding machine 10 according to a first embodiment of the present invention. The injection press molding machine 10 includes a stationary mold 12
And a mold clamping device 16 that opens and closes the movable mold 14, and a molding cavity 18 formed by mold-fixing the fixed mold 12 and the movable mold 14 by the mold clamping device 16. An injection device 22 for injecting and supplying the resin material 20 is provided.

More specifically, in the mold clamping device 16,
A substantially thick rectangular plate-like fixing plate 24 is fixedly provided on a base (not shown), and the fixing die 12 is fixed to one surface (the left side surface in the figure) of the fixing plate 24. It is attached. A substantially rectangular plate-shaped support plate 26 is disposed on the fixed platen 24 on the surface on which the fixed mold 12 is mounted, and is separated by a predetermined distance, and the support plate 26 is placed on the base. It is fixed and is opposed to the fixed platen 24. Further, four tie bars 28 are stretched between the facing surfaces of the fixed board 24 and the support plate 26 so as to connect the four corners thereof, and are arranged and fixed in parallel with each other.

Further, a movable block 30 in the form of a rectangular block is disposed between the fixed board 24 and the support plate 26, and the surface of the movable board 30 facing the fixed board 24 (the right side in the figure). The movable mold 14 is fixedly attached to the (surface). In addition, tie bars 28 are penetrated at the four corners of the movable platen 30 so that the movable platen 30 is guided / guided by the four tie bars 28 while approaching / separating from the fixed platen 24. It is possible to move to.

Further, the fixed platen 24 is provided with side cylinders 32, 32 constituting a hydraulic cylinder mechanism 31 for opening and closing the mold, and piston rods 34, 34 driven by the side cylinders 32, 32, respectively. Each is fixed to the movable platen 30. Accordingly, the movable plate 30 is displaced in the approach / separate direction with respect to the fixed plate 24 by the driving force generated between the side cylinders 32, 32 and the piston rods 34, 34. The movable die 30 and the movable die 14 are opened and closed by the approach / separation displacement of the movable plate 30 with respect to the fixed plate 24. The hydraulic cylinder mechanism for opening and closing the mold is known, and details of a hydraulic circuit and the like are omitted.

The tie bars 28 of the movable platen 30 penetrate through the hydraulic cylinder mechanisms 3 for clamping.
5 is formed. Further, each of the pistons 38 driven by the main cylinder 36 is integrally formed with a hollow rod portion 40 extending to both sides in the sliding direction.
And the rod portion 40 are externally inserted into the tie bar 28 and assembled so as to be slidable in the axial direction. In addition, each rod part 4
The end portion of the fixed plate 24 on the side of the fixed plate 24 can be inserted into the fixed plate 24, and an engaging groove 42 having a concave and convex shape extending in the circumferential direction is formed on the outer peripheral surface of the front end portion. I have. Furthermore, chuck members 46, 46 having engagement projections corresponding to the engagement grooves 42 of the rod portion 40 are respectively provided in the insertion holes 44 of the fixed board 24 into which the tip portion of the rod portion 40 is inserted. Also provided are chuck cylinders 48, 48 for reciprocatingly driving the chuck members 46, 46 in directions approaching / separating from the rod portion 40 in a direction perpendicular to the axis. Then, in a state where the chuck members 46, 46 are disengaged from the engagement grooves 42 of the rod portion 40 by the chuck cylinders 48, 48, the axial displacement of the rod portion 40 on the tie bar 28 is allowed,
The distal end portion of the rod portion 40 can be inserted into / extracted from the insertion hole 44 of the fixed board 24. On the other hand, under the condition that the tip portion of the rod portion 40 is inserted into the insertion hole 44 of the fixed board 24, the chuck members 48, 48
46 is projected toward the rod portion 40, and the rod portion 4
The engagement with the engagement groove 42 of the
Is fixed to the fixed platen 24, and the axial displacement on the tie bar 28 is maintained in a state where it is prevented.

Thus, as shown in FIG.
By driving the piston rods 34 of the respective side cylinders 32 to relatively bring the fixed platen 24 and the movable platen 30 closer to each other, the fixed cylinders 12 and the movable platen 14 are closed and the main cylinders 36 are closed. After driving the piston 38 to insert the rod portion 40 into the insertion hole 44 of the movable platen 30 and engaging the chuck members 46, 46 with the rod portion 40 by the chuck cylinders 48, 48, the main cylinder 36 By driving the piston 38, the distance between the fixed platen 24 and the movable platen 30, that is, the fixed mold 1 is increased.
A mold clamping force and a pressing pressure can be exerted between the movable mold 2 and the movable mold 14.

The fixed mold 12 and the movable mold 14 are matched with each other in this manner, so that both the molds 1 are formed.
A molding cavity 18 made of a resin material is formed between the two mating surfaces. In addition, a nozzle touch portion of the injection device 22 is formed in the center portion of the fixed mold 12 through the fixed plate 24, and the fixed mold 12 is provided with the nozzle touch portion from the nozzle touch portion to the molding cavity 18. An extended runner portion is formed, and the molten resin material injected from the injection device 22 is guided to the molding cavity 18 and supplied through the runner portion. Further, the ejector pins 50 are provided in the movable mold 14.
Are arranged so as to be movable in the mold opening / closing direction, and the ejector pins 50 are caused to protrude by an ejector mechanism 52 provided on the movable platen 30 so that the molds 12 and 14 are movable when the molds 12 and 14 are opened after molding. The molded product attached to the mold 14 is protruded, released from the mold, and taken out.

On the other hand, in this embodiment, an in-line screw type injection device is employed as the injection device 22.
An injection screw 56 is rotatably accommodated in a hollow cylindrical heating cylinder 54 so as to be axially displaceable. The injection screw 56 is driven to rotate around a central axis by a drive motor 58,
The pair of injection cylinders 60 are driven in the axial direction. Then, the entirety of the injection device 22 is moved toward the mold clamping device 16 by driving means (not shown), and the tip of the nozzle 62 of the heating cylinder 54 in the injection device 22 is contacted with the nozzle of the fixed mold 12 in the mold clamping device 16. In the injection device 22, the resin material is supplied into the heating cylinder 54 and the injection screw 56 is driven to rotate by the drive motor 58 in a state where the resin material is brought into contact with the screw, thereby heating and melting the resin material. It is sent forward and stored, and then the injection screw 56 is connected to the injection cylinder 60,
A predetermined amount of the molten resin material is injected from the tip hole of the nozzle 62 by driving the mold
Can be supplied to the molding cavity 18 through a runner section provided in the mold. In addition, the structure itself of such an in-line screw type injection device is known, and details of a hydraulic circuit and the like are omitted.

When performing the injection press molding in the injection press molding machine 10 including the above-described mold clamping device 16 and injection device 22, for example, first, the injection device 22 is connected to the mold clamping device 16 After the nozzle is touched by approaching the movable platen, the hydraulic pressure is supplied to and discharged from the side cylinder 32 in the mold clamping device 16 to move the movable platen 30 to the fixed platen 24 at a high speed by the mold opening / closing hydraulic cylinder mechanism 31. Thus, the fixed mold 12 and the movable mold 14 are matched. Subsequently, the chuck members 46, 46 are engaged with the rod portion 40 by the chuck cylinders 48, 48, and the rod portion 40 is fixed to the fixing plate 24. In addition, the injection device 2
In 2, the resin material is plasticized and measured by the rotation operation of the injection screw 56 in parallel with the mold matching operation and the like by the mold clamping device 16, and stored in front of the injection screw 56. Then, in the injection device 22, the injection screw 5
The molten resin material 20 is injected by driving the 6 forward, and supplied into the molding cavity 18 formed by the mold clamping device 16. Then, in the mold clamping device 16,
By applying a press pressure between the movable platen 30 and the fixed platen 24 by the mold clamping hydraulic cylinder mechanism 35 and clamping the movable platen 30 and the fixed platen 24 with the press pressure, the fixed die 12 and the movable die 12 are fixed. Molding cavity 1 formed between 14
8 is reduced to a cavity shape corresponding to a target product, and
The supplied resin material 20 is spread and filled. After cooling for a predetermined time, the fixed platen 24 and the movable platen 30 are opened, and the molded product is moved by the ejector mechanism 52 to the movable mold 1.
The desired product can be obtained by releasing from the mold 2 and taking it out.

At the time of such molding, the resin material 20 supplied to the molding cavity 18 is generally in the vicinity of the connection portion of the runner portion before the action of the pressing pressure, as shown in FIG. It exists in the shape of a dumpling. Then, when the pressing pressure is applied, as shown in FIG.
4 is expanded so as to be crushed in the molding cavity 18, and is filled in the molding cavity 18.

In this regard, the injection press molding machine 10 of the present embodiment is provided with a mold clamping force adjusting device, and even before the press pressure is applied, the molding cavity 18 is controlled.
The pressure exerted on the dumpling portion 64 of the resin material 20 supplied to the nozzle is adjusted.

More specifically, such a mold clamping force adjusting device includes:
A pressure sensor 66 as detecting means for detecting the pressure of the dumpling portion 64, a target value setting device 68 as target pressure setting means for inputting and setting a target value for pressure setting of the dumpling portion 64,
By controlling the supply and discharge of hydraulic oil to and from the hydraulic cylinder mechanism for mold clamping 35 so that the detected pressure value of the basket portion 64 obtained by the pressure sensor 66 becomes the target pressure value set by the target value setting device 68. The apparatus includes a cylinder mechanism control device 70 as control means for adjusting the mold clamping pressure of the molds 12 and 14.

As shown in FIG. 1, the pressure sensor 66 is provided in, for example, the fixed mold 12 or the movable mold 14 and is provided with the resin material 20 supplied to the molding cavity 18.
The pressure sensor 66a which detects the pressure of the above is suitably adopted. Alternatively, provided in the heating cylinder 54 of the injection device 22,
A pressure sensor 66b for detecting the pressure of the resin material 20 injected and supplied from the nozzle 62 to the molding cavity 18 is suitably employed. Alternatively, it is provided in the injection cylinder 60 of the injection device 22 and the
A pressure sensor 66c or the like for detecting an injection pressure when injecting the resin material 20 into the resin may be employed. In FIG. 1, the three pressure sensors 66a, 66b, and 66c are provided together.
One of the pressure sensors 6 is selected by the selection switch 72.
6 is selectively used. By thus providing three types of pressure sensors 66a, b, and c together, an appropriate pressure sensor 66a, b, and c can be used in accordance with the resin material, the shape of the molded product, and the like. Although it is possible to appropriately select and employ a suitable pressure sensor, it is of course possible to provide only one pressure sensor 66. Further, as the pressure sensor, various types of known sensors capable of extracting a pressure level as an electric signal, such as a piezoelectric sensor, a semiconductor sensor, and a strain gauge sensor, can be appropriately employed. In addition, the value detected by the pressure sensor 66 can be subjected to error correction with the actual pressure value exerted on the dumpling portion 64 of the resin material 20 in accordance with the type or the like to be adopted.

The target value setter 68 operates the dumping portion 6 of the resin material 20 supplied to the molding cavity 18 by an external operation using a keyboard, a switch element or the like.
4 is configured by an external input device capable of setting and changing a pressure value to be exerted on the pressure sensor 4 and outputting an electric signal corresponding to the magnitude of the pressure value.

Further, the cylinder mechanism control unit 70 compares the measured pressure value detected by the pressure sensor 66 with the target pressure value set by the target value setting unit 68, and generates a control signal corresponding to the difference between the two values. Output comparator 74
And a pressure-controlled servo valve 76 for controlling the supply and discharge of hydraulic oil to and from the hydraulic cylinder mechanism 35 for clamping, which applies clamping force in the clamping device 16, according to the control signal obtained by the comparator 74. It is comprised including. That is, the mold-clamping hydraulic cylinder mechanism 35 is a backward-acting cylinder mechanism in which cylinder chambers are formed on both sides of the piston 38 in the main cylinder 36, and a hydraulic pump 78 and a drain are provided to each cylinder chamber by a servo valve 76. 8
The output of the hydraulic cylinder mechanism 35 for mold clamping, and consequently, the mold clamping force exerted on the molds 12 and 14 can be adjusted by switching the connection of 0 and adjusting the supply pressure of the hydraulic oil to each cylinder chamber. It has become. In the drawing, the action mechanism of the mold clamping force including the mold clamping hydraulic cylinder mechanism 35 and the like is shown only on one tie bar 28, but the same mold clamping force An action mechanism of a mold clamping force including a hydraulic cylinder mechanism is provided.
By controlling the operation of the fixed mold 12 and the movable mold 14, a mold clamping force can be exerted in cooperation.

In the step of fixing the fixed mold 12 and the movable mold 14 under the clamping force of the mold clamping hydraulic cylinder mechanism 35 and injecting and supplying the resin material 20 to the formed molding cavity 18. , Mold clamping hydraulic cylinder mechanism 35
The pressure of the hydraulic oil supplied to and discharged from the cylinder chamber of the
The servo valve 76 is controlled based on the control signal input from the controller, so that the pressure of the resin material 20 supplied to the molding cavity 18 is maintained at the target value set by the target value setting device 68. Feedback control is performed.

Further, after a predetermined amount of the resin material 20 is injected and supplied to the molding cavity 18 under the control of the mold clamping pressure, the servo valve 7 is controlled by a control system (not shown).
By the control of 6, so that a predetermined press pressure is obtained,
The supply / discharge control of the hydraulic oil to / from the mold closing hydraulic cylinder mechanism 35 is performed, and the press pressure operation as described above is performed.

Therefore, such an injection press molding machine 10
According to the injection molding, the predetermined mold clamping force set by the target value setting device 68 is effective for the resin material 20 supplied into the molding cavity 18 even in the process before the press pressure is applied. To be applied to
The pressure applied to the resin material 20 (the dumpling portion 64) can be continuously controlled from the time when the resin material 20 is supplied into the molding cavity 18.

Therefore, also in the step before the application of the pressing pressure, the molding surface can be advantageously transferred to the dumpling portion 64 before the thick skin layer is formed. It is possible to obtain excellent transferability as in the case of the spread portion formed after the action.

Further, since the pressure exerted on the resin material 20 in the step before the action of the pressing pressure can be arbitrarily set and adjusted, by setting the pressure equal to or less than the pressing pressure. As compared with the case where the mold is clamped with a fixed mold clamping force from the beginning before the injection of the resin material, the occurrence of internal stress in the resin material can be suppressed, and product defects such as warpage and distortion can be advantageously prevented. You can do it.

Although the embodiment of the present invention has been described in detail above, this is merely an example, and the present invention is not to be construed as being limited in any way by the specific description of the embodiment.

For example, in order to control the mold clamping force by the mold clamping hydraulic cylinder mechanism 35 in the cylinder mechanism control unit 70, instead of the servo valve 76, as shown in FIG. Type relief valve 82
It is also possible to adjust the pressure of the hydraulic oil supplied from the hydraulic pump 78 to the cylinder chamber of the mold clamping hydraulic cylinder mechanism 35 via the electromagnetic switching valve 84.

The detecting means for detecting the pressure of the resin material 20 (the dumpling portion 64) supplied to the molding cavity 18 is not limited to directly detecting the pressure as in the pressure sensors 66a, 66b and 66c of the above embodiment. It is also possible to employ a detecting means for detecting a value corresponding to the pressure of the resin material 20. Specifically, for example, as shown in FIG. 4, pressure sensors 86a and 86b that detect the pressure (oil pressure) of each cylinder chamber of the hydraulic cylinder mechanism 35 for mold clamping are used.
The difference between the detected values of the two pressure sensors 86a and 86b obtained by the adder 88 can be used as the actual measured pressure value (the detected pressure value). In this case, for example, the value of the difference between the detection values of the pressure sensors 86a and 86b obtained by the adder 88 and the dumpling portion 64
The relational expression with the pressure value exerted on the comparator 7 is determined in advance based on actual measurement data and the like.
In 4, it is desirable to obtain a deviation (control signal) between the value of the difference between the detection values of the pressure sensors 86a and 86b and the target value input from the target value setting device 68. Alternatively, for example, the two pressure sensors 86 when applying a pressing pressure to the resin material 20 supplied to the molding cavity 18.
Based on the difference between the detected values of a and 86b, the target value setting device 68 is used to input what percentage of the pressure is applied to the dumpling portion 64 before the press pressure is applied.
In FIG. 4, the mold is set such that a difference value corresponding to the set% inputted by the target value setting device 68 is generated between the detection values of the two pressure sensors 86a and 86b with respect to the difference value at the time of the press pressure acting as the reference. It is also possible to adjust the mold clamping force by controlling the supply and discharge of hydraulic oil to and from each cylinder chamber of the clamping hydraulic cylinder mechanism 35.

Further, the injection press molding machine 10 as described above
In the above, the press pressure value can be adjusted and set to an arbitrary value by using the pressure sensor 66, the cylinder mechanism control device 70 and the like in accordance with an input from the target value setting device 68.

In the injection press molding as described above, the stationary mold 12 and the movable mold 1 are placed in the initial stage of injection when the supply of the resin material 20 to the molding cavity 18 is started.
It is not necessary that the mold 4 is opened by a predetermined amount from the final mold clamping position, and the mold may be matched in a completely mold closed state.

Furthermore, it is desirable that the pressure applied to the resin material 20 (the dumpling portion 64) before the pressing pressure is applied is substantially the same as the pressing pressure, whereby the transferability of the dumpling portion 64 is more advantageously improved. This can be achieved, but is not limited thereto. For example, the pressure applied to the dumpling may be set to a pressure value smaller than the pressing pressure.

In addition, the present invention is advantageously applied to an injection press molding machine used for molding various products and an injection press molding method employed for molding various products. The scope of the present invention is not limited by the type of the product, the resin material, the mold, and the like.

In addition, although not enumerated one by one, the present invention
Based on the knowledge of those skilled in the art, various changes, modifications, improvements, and the like can be made, and unless such embodiments depart from the spirit of the present invention.
Both are included in the scope of the present invention,
Needless to say.

[0049]

As is clear from the above description, according to the present invention, it is possible to control the pressure exerted on the resin material filled in the molding cavity even before the pressing pressure is applied. By applying an appropriate pressure to the resin material even before the pressing pressure is applied, avoiding excessive pressure acting on the resin material and suppressing defects such as warpage and distortion of the product, the molding surface is advantageously improved. Transfer can be performed, and thereby, a non-defective product having no warp or distortion and having excellent transferability can be stably formed.

[Brief description of the drawings]

FIG. 1 is an explanatory view schematically showing a configuration of an injection press molding machine as a first embodiment of the present invention.

FIG. 2 is an explanatory view showing an operation state when a press pressure is applied in the injection press molding machine shown in FIG.

FIG. 3 is an explanatory view schematically showing a configuration of an injection press molding machine as a second embodiment of the present invention.

FIG. 4 is an explanatory view schematically showing a configuration of an injection press molding machine as a third embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 10 injection press molding machine 12 fixed mold 14 movable mold 16 mold clamping device 18 molding cavity 20 resin material 22 injection device 24 fixed plate 30 movable plate 66 pressure sensor 68 target value setting device 70 cylinder mechanism control device 74 comparator 76 servo valve

Claims (3)

[Claims] Injection press molding in which a resin material is injected and supplied into a molding cavity formed by combining a fixed mold and a movable mold, and then press molding is applied to the fixed mold and the movable mold. A method for directly or indirectly detecting a pressure applied to the resin material during injection supply of the resin material to a molding cavity, wherein a pressure detection value of the resin material is set in advance. An injection press molding method, wherein a mold clamping force between the fixed mold and the movable mold is adjusted so as to be a target value. 2. The injection press molding method according to claim 1, wherein the target value is kept constant over the entire time of injecting and supplying the resin material to a molding cavity. 3. A mold clamping device for forming a molding cavity by combining a fixed mold and a movable mold, and an injection device for injecting and supplying a resin material to the molding cavity, wherein the injection device supplies resin to the molding cavity. After injecting and supplying the material,
In an injection press molding machine for applying a press pressure to a fixed mold and a movable mold by the mold clamping device, the pressure applied to the resin material injected and supplied to the molding cavity by the injection device is directly or Detecting means for indirectly detecting; target pressure setting means for setting a target value of pressure exerted on the resin material injected and supplied to the molding cavity; and a pressure detection value obtained by the detecting means for detecting the target pressure. So that the target value set in
Control means for adjusting a mold clamping force in the mold clamping device until the press pressure is applied.