JP5394802B2 - Injection molding method and injection molding apparatus - Google Patents

Description

  The present invention relates to a mold, a mold clamping device for clamping a mold plate to which the mold is attached, and an injection device for injecting a molten injection material into a cavity formed in the mold. The present invention relates to an injection molding method and an injection molding apparatus using an apparatus comprising:

  Both electric injection molding machines, hydraulic injection molding machines, and molding machines that inject a molten injection material from a plunger are well known, and generally consist of an injection device and a mold clamping device. . Hereinafter, a conventional example of an electric injection molding machine will be described. As shown in FIG. 3A, the electric injection molding machine includes a conventionally known injection device S and a known toggle type mold clamping device T. The injection device S is composed of an injection cylinder 50, a screw or the like provided in the cylinder 50 so as to be driven in the rotational direction and the axial direction, and a hopper is provided behind the injection cylinder 50. A pellet-shaped solid resin material is supplied from the hopper to the injection cylinder 50 for a predetermined amount. Although the drive unit for driving the screw is not shown in FIG. 3, the motor includes a plasticizing motor, an injection motor, etc. as known in the art, and the output shaft of these motors is a speed reducer such as a gear, spline. It is coupled to the screw shaft through a mechanism or the like. Therefore, the screw can be driven both in the plasticizing direction and in the injection direction, and can also be driven or moved in the axial direction during plasticization.

  The toggle type mold clamping device T is also well known in the art and will not be described in detail. However, a fixed platen 60 fixedly provided on the bed and a mold clamping housing provided axially movable on the bed. 62, four tie bars 63, 63,... Provided between the fixed plate 60 and the mold clamping housing 62, and a movable plate 64 that is inserted through these tie bars 63, 63,. A toggle mechanism 70 or the like provided between the mold clamping housing 62 and the movable plate 64 is used. The toggle mechanism 70 includes a pair of short links, a pair of long links 74 and 74, one cross head 71, a pair of cross links, and the like. One end of the pair of long links 74, 74 is pivotally attached to brackets 64 ′, 64 ′ attached to the movable plate 64. These brackets 64 ′ and 64 ′ are provided at the center in the horizontal direction of the movable plate 64 and at both the upper and lower ends. In other words, these brackets 64 ′ and 64 ′ are located outside the movable mold 66.

  The cross head 71 is attached to the tip of a ball screw 72 in a conventionally known manner, and the ball screw 72 is inserted into a through hole formed in a substantially central portion of the mold clamping housing 62. A ball nut 73 into which the ball screw 72 is screwed is rotatably provided in the mold clamping housing 62. Since this ball nut 73 is provided in the mold clamping housing 62 in a state where the movement in the axial direction is restricted, when the ball nut 73 is driven to rotate, the ball screw 72 is driven in the axial direction and the crosshead 71 is closed. It is driven in the direction or mold opening direction.

  A fixed mold 65 is attached to the fixed platen 60 configured as described above, and a movable mold 66 is attached to the movable platen 64. As is well known, a cavity for obtaining a molded product is formed on the parting line surfaces of the fixed side mold 65 and the movable side mold 66, that is, the mold mating surfaces.

  Therefore, the screw is rotationally driven by the plasticizing electric servo motor of the screw driving unit to measure the injection material into the accumulation chamber in front of the injection cylinder, and the cross head 71 of the toggle mechanism 70 is driven to move the movable side mold. 66 is clamped to the fixed side mold 65, and the screw is driven in the axial direction to inject and fill the cavity, and after waiting for cooling and solidification, the movable side mold 66 is opened to obtain a molded product. Can do.

  When the cross head 71 of the toggle mechanism 70 is driven during molding as described above, the tie bars 63, 63,... Are elastically deformed and stretched, and the mold is clamped by the restoring force. That is, the movable platen 64 receives a force in the direction indicated by the arrow F in FIG. 3A by the toggle mechanism 70 and receives a reverse force from the movable mold 66. That is, the movable platen 64 receives a force in the direction of arrow F at the brackets 64 ′ and 64 ′ located outside the movable side mold 66 and receives a force in the opposite direction at the central portion. A bending moment M ′ acts. Similarly, the fixed platen 60 receives a force in the direction indicated by the arrow F ′ from the tie bars 63, 63, and receives a reverse force from the fixed mold 65 attached to the center of the fixed platen 60. receive. Accordingly, the bending moment M ′ also acts on the fixed platen 60. Due to the bending moments M ′ and M ′, the fixed platen 60 and the movable platen 64 are deformed and curved. The curved state is indicated by a broken line in FIG. As a result, the fixed-side mold 65 and the movable-side mold 66 are also curved, and a minute gap s is generated in the vicinity of the center portion of the mold matching surface. If gaps occur, it will interfere with precision molding. Or a burr | flash comes to arise in a molded article. Patent documents 1 to 3 propose a mold platen or a mold clamping device which attempts to solve such a problem of the gap s.

JP-A-9-38984 JP 2005-205819 A Special republication WO2006 / 115141

  Patent Document 1 discloses a fixed platen 80 as shown in FIG. That is, it comprises a first plate-like member 82 having a mold surface 81 to which a fixed mold is attached, and a second plate-like member 85 having an end surface 84 to which end portions of tie bars 83, 83,. A stationary platen 80 is shown. The first plate-like member 82 and the second plate-like member 85 are integrated by an intermediate support member 86 having a substantially bowl shape on the side surface. Since the intermediate support member 86 has a substantially bowl shape, the force F acting on the mold surface 81 is dispersed by the intermediate support member 86 like F1 and F1 and transmitted to the second plate member 85. become.

  Patent Document 2 discloses a stationary-side pattern board 90 as shown in FIG. The mold platen 90 includes a mold platen body 91 and a mold fixing member 95 shown in FIG. 5A. The fixed mold 96 is attached to the mold platen body 91 via the mold fixing member 95. It can be attached. A protrusion 93 is formed on the surface of the mold body 91 on the side where the mold is attached. The protrusion 93 and the mold body 91 are integrated by a plurality of tapered ribs 94, 94. Yes. The movable side platen 91 'is similarly configured. FIG. 5A shows a state in which the molds 96 and 96 ′ are attached to the mold plates 91 and 91 ′ configured as described above through the mold fixing members 95 and 95 ′, and the molds are clamped. ing.

  Patent Document 3 discloses a mold clamping device including a side pressure that suppresses deformation and deformation of a mold sidewall end portion outward. The side pressure is provided on the pair of supports, a pair of supports that are slidably supported with respect to the tie bar, a movement positioning unit that positions the supports at a predetermined position, and the fixed mold. Or it is comprised from the horizontal fastening means which presses the side part of a movable metal mold | die.

  In the fixed platen 80 described in Patent Document 1, since the intermediate support member 86 has a substantially bowl shape and the force is dispersed, the deformation amount of the mold parting surface is small, and the generation of burrs is suppressed. I can. However, the fixed platen 80 includes a first plate-like member 82 to which a fixed-side mold is attached, and a second plate-like member 85 to which ends of the tie bars 83, 83,. The plate-like member 82 and the second plate-like member 85 have a structure in which the side surface shape is integrated by an intermediate support member 86 having a substantially bowl shape, so that the structure is complicated and the manufacturing cost is high. Further, since the intermediate support member 86 has a bowl shape, the cost for the curved surface processing increases. Furthermore, there is also a problem that it cannot be applied to existing molds. The mold platen 90 described in Patent Document 2 has high rigidity because the projecting portion 93 and the platen plate body 91 are coupled by a plurality of tapered ribs 94, 94. Therefore, although it seems that the template 90 hardly deform | transforms, a problem is also recognized. That is, the molds 96 and 96 ′ are attached to the protruding portion 93 via predetermined mold fixing members 95 and 95 ′. However, the deformation of the mold fixing members 95 and 95 ′ is particularly considered. Not. Further, the size of the protrusion 93 is a fixed size regardless of the size of the dies 96, 96 'to which the protrusions 93 are attached. Therefore, when the large molds 96 and 96 ′ are attached as compared with the size of the protruding portion 93, the mold fixing members 95 and 95 ′ and the molds 96 and 96 ′ are deformed, and from the center. Deformation becomes particularly large at a distant position, and a gap occurs in the parting surface, resulting in a molding defect. Furthermore, since the platen 90 described in Patent Document 2 has a complicated rib structure, the structure is complicated and expensive, and there is a problem that it must be manufactured specially. According to the invention described in Patent Document 3, the side pressure of the fixed mold or the movable mold that is clamped can be directly clamped by the side pressure, so that the deformation due to the outward bending of the mold side wall tip portion. Can be suppressed. There is also an advantage that it can be applied to existing mold clamping devices. However, the side pressure is composed of a pair of supports, moving positioning means, and lateral fastening means, and the structure is complicated and expensive. Further, the positioning means and the lateral fastening means require an operation different from the normal molding operation, and the entire molding operation is complicated.

  The present invention has been made in view of the above-described problems, and is an injection molding method capable of precision molding by the same operation as a conventional normal molding operation and obtaining a high-quality molded product without burrs or the like. The purpose is to provide. Another object of the present invention is to provide an injection molding apparatus that has a very simple structure and can be manufactured at low cost despite the fact that burrs and the like are not generated and precision molding is possible. It is another object of the present invention to provide an injection molding apparatus that can easily cope with the size of a mold and can be easily applied to an existing injection molding apparatus.

In order to achieve the above object, the present invention provides a mold plate of a mold clamping device comprising a mold plate, a mold attached to the mold plate, and a plurality of tie bars for clamping the mold plate. A correction board having a substantially plate shape is interposed between the mold and the mold. The end of the correction panel has a portion that protrudes outward from the mold by a predetermined amount. A thin portion is formed in the vicinity of the protruding portion. This thin portion serves as a relief portion that allows or allows deformation that occurs in the mold platen due to the clamping force. The correction board includes a correction board body and an attachment that is detachably fitted to or attached to the correction board body. As the attachment, a plurality of attachments having different sizes of portions contacting the mold plate or the mold are prepared. At this time, attachments having different thicknesses can be prepared. Then, one of the plurality of attachments is selected and fitted into the correction panel main body.

Thus, in order to achieve the above object, the invention described in claim 1 is an injection apparatus for injecting a molten injection material, and a mold clamping apparatus in which the injection material injected from the injection apparatus is injected and filled. The mold clamping device comprises a mold plate, a mold that is attached to the mold plate and has a cavity on its parting surface, and a plurality of tie bars that clamp the mold plate, Between the mold platen and the mold, a correction plate which is substantially plate-shaped and has a relief portion cut off by a predetermined amount in the thickness direction in the vicinity of the end protruding outward from the mold by a predetermined amount There the molding apparatus adapted to be interposed, the correction plate is a combination of a correction plate body that is common, and a plurality of attachment which is mounted for selectively detachable to the body, wherein Attachment is before The size of the mounting portion which fits into the recess for fitting the correction board main body consists of a relief forming portion constituting the relief portion in contact with the mold platen protruding from said mounting portion, the size of the relief portion forming portion Each has a different length, thereby forming a plurality of attachments .

As described above, according to the present invention, the mold plate is clamped between the mold platen and the mold with a correction plate having a substantially plate shape and its end portion protruding outward from the mold by a predetermined amount. The deformation that occurs in the mold platen due to the force is formed so as to be released at the thin portion near the protruding end of the correction platen, or because the relief plate is formed on the correction platen, the mold clamping The curved deformation of the mold platen caused by the force is allowed by the thin portion, or is released by the relief portion, and is concentrated in the vicinity of the end portion of the mold platen. Thereby, no deformation occurs in the middle part of the mold platen, that is, the part to which the mold is attached. That is, there is no gap in the mold matching surface of the mold. Therefore, according to the present invention, an effect peculiar to the present invention that precision molding can be performed without causing burrs can be obtained. Further, the correction board according to the present invention has a substantially plate shape and has a simple structure having only a thin part or a relief part in the vicinity of the end part thereof, so that it can be provided at a very low cost. Furthermore, the correction plate is only interposed between the mold plate and the mold, or the die is only attached to the plate via the correction plate, and no special means is required. The molding can be performed by the same operation as a conventionally known molding operation. That is, the molding cost does not increase. Further, since the correction plate is interposed between the mold plate and the mold, it can be easily applied to an existing injection molding apparatus. In particular, according to the present invention, the correction panel includes a correction panel main body and an attachment fitted or attached to the correction panel main body, and the attached attachment is detachably attachable to the correction panel main body. since in the attachment that will be selected from among a plurality of different attachment sizes, the strength of the mold platen, the mold size, can be formed by selecting an optimal attachment due to differences such as the mold clamping force.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows embodiment of this invention, The (a) is a side view which shows the whole by making a cross section partially, The (a), (d) is the 1st, 2nd embodiment of the principal part, respectively. The side view which expands and shows that, (c) is a side view explaining the effect | action of 1st Embodiment. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows embodiment of the principal part of this invention, (a), (b) is a side view which expands and shows each of 3rd, 4th embodiment of a principal part. It is a figure which shows the conventional injection molding machine, The (a) is a side view which shows the whole, The (a) is a side view which expands and shows the action state of the principal part. It is a side view which shows the conventional platen. It is a figure which shows another conventional type | mold platen, The (a) is a perspective view of a fixed platen, The (a) is a side view which shows a movable platen and a fixed platen in a mold clamping state.

  In the present invention, a metal material having a low melting point can be applied to the injection material, and a hydraulic direct pressure clamping device can be applied to the mold clamping machine. Further, the molten injection material is directed from the plunger toward the mold cavity. Although applicable to injection / filling molding, an example in which the embodiment of the present invention is molded with resin by a toggle type electric injection molding machine will be described below with reference to FIGS. The injection molding machine according to the present embodiment generally includes an injection device 1 and a mold clamping device 10. The injection device 1 includes a cylinder barrel 2, a screw provided in the cylinder barrel 2 so as to be driven in the rotational direction and the axial direction, a drive unit for driving the screw in the rotational direction and the axial direction, and the like. Yes. A hopper 3 for temporarily storing a resin material is provided behind the cylinder barrel 2. The drive unit includes a plasticizing electric servo motor, an injection electric servo motor, and the like, and a gear device, a spline mechanism, and the like are interposed between the output shaft and the screw shaft of these servo motors. Accordingly, the screw can be rotated to be plasticized, axially driven to be ejected, and further moved in the axial direction when driven in the rotational direction. The injection device 1 configured as described above is provided so as to be movable in a direction in which it abuts against the mold clamping device 10 and a direction in which it is separated.

  The toggle mechanism 20 of the mold clamping device 10 is configured in substantially the same manner as the conventional one. That is, the fixed platen 11 fixed on the bed B, the mold clamping housing 13 provided on the bed B so as to be movable in the axial direction at an interval from the fixed platen 11, the fixed platen 11 and the mold clamping housing 13 , Four tie bars 14, 14 provided between the movable platen 12 and the movable platen 12 guided and moved in the axial direction by the tie bars 14, 14,... The toggle mechanism 20 includes a mold clamping servo motor that drives the toggle mechanism 20.

  One end of each of the tie bars 14, 14,... Is passed through the four corners of the fixed platen 11 and fixed to the fixed platen 11. The other ends of the tie bars 14, 14,... Penetrate through the four corners of the mold clamping housing 13 and extend to the outside. Further, on the outside of the mold clamping housing 13, mold thickness adjusting nuts 15, 15,.

  Since the toggle mechanism 20 is configured as conventionally known, it will not be described in detail. However, the pair of relatively long first links 21 and 21, the pair of relatively short second links 22 and 22, and the pair of third links. The crosshead 23 and the like. One end of the first links 21, 21 is pin-coupled to brackets 21 ′, 21 ′ fixed to the movable platen 12, and the other end is the same as one end of the second links 22, 22. It is pin-coupled to. The brackets 21 ′ and 21 ′ are provided in the vicinity of the upper and lower ends of the movable platen 12 in the lateral center. In other words, the brackets 21 'and 21' are located outside the movable mold K2. The other ends of the second links 22 and 22 are similarly pin-coupled to the mold clamping housing 13 and the ends of the third link are similarly pin-coupled to the second links 22 and 22 and the crosshead 23, respectively.

  A through hole is formed in a substantially central portion of the mold clamping housing 13, and a ball nut 25 is rotatably provided outside the mold clamping housing 13 in such a manner that axial movement is restricted in alignment with the through hole. Yes. A ball screw 26 is screwed onto the ball nut 25. One end of the ball screw 26 is attached to the crosshead 23 in a conventionally known manner. The ball nut 25 is rotationally driven in a predetermined direction by a servo motor (not shown) via a belt 27. Therefore, when the ball screw 26 is rotationally driven by the servo motor in a predetermined direction, the cross head 23 is driven in a predetermined axial direction, and the movable platen 12 is driven in the mold closing direction or the mold opening direction.

  A fixed die K1 is directly attached to the fixed platen 11 as is well known in the art. On the other hand, according to the present embodiment, the movable platen 12 is attached to the movable platen 12 via the correction plate 30. On the parting surface side of these molds K1 and K2, a cavity for imparting a shape to the molded product is formed as is conventionally known.

  The first embodiment of the correction board 30 is shown in an enlarged manner in FIG. The correction board 30a according to the first embodiment has a plane shape substantially the same as that of the movable board 12, and four corners thereof are inserted into the four tie bars 14, 14,. The correction board 30a has a flat contact surface 31a in contact with the movable board 12, and a similarly flat mounting surface 32a to which the movable mold K2 is attached. Since the existing movable platen 12 is provided with means for attaching the movable side mold, the contact surface 31a of the correction plate 30a is also provided with attachment means as provided in the existing die. Alternatively, new attachment means are provided. The mounting surface 32a is also provided with a mold mounting means having a well-known form.

  The upper and lower ends of the contact surface 31a of the correction panel 30a thus configured, that is, the portions corresponding to the brackets 21 ′ and 21 ′ have a predetermined length as shown in FIG. Over the course, it is scraped off to a predetermined thickness. Thereby, in this Embodiment, the escape part 33a of the predetermined width w selected, for example as 0.5 mm is formed. Since the escape portion 33a is formed, the contact surface 31a is smaller than the projection surface of the movable mold K2 onto the movable platen 12. In addition, the upper and lower ends of the correction board 30a are apparently thin. Therefore, when the movable platen 12 bends during mold clamping, the correction plate 30 is slightly deformed by the relief portion 33a, and the curve of the movable platen 12 is alleviated, so that the movable mold K2 is not deformed.

  Next, the operation of the above embodiment will be described. A stationary mold K1 is attached to the stationary platen 11 as is conventionally known. The movable side mold K2 is attached to the movable platen 12 through the correction plate 30a by the attaching means as described above. The state of attachment in this way is shown in FIG. A screw is rotationally driven by a plasticizing servo motor of the drive unit, and a resin material is measured by a predetermined amount in a storage chamber in front of the cylinder barrel 2. The ball screw 26 of the toggle mechanism 20 is rotationally driven to drive the crosshead 23. As a result, the movable mold K2 is clamped with respect to the fixed mold K1 to form a cavity. The screw is driven in the axial direction by an injection servo motor to inject and fill the cavity, and after waiting for cooling and solidification, the movable mold K2 is opened. Then, the molded product is ejected.

  When the mold is clamped as described above, a bending moment M acts on the movable platen 12 and the movable platen 12 is deformed so as to be curved, as shown in FIG. The deformable movable platen 12 'is shown by a broken line in FIG. At this time, since the correction board 30a is also deformed, the contact surface 31a 'is also curved at the center. By the way, since the relief portion 33 a is formed in the correction plate 30 a, the upper and lower end portions are slightly curved in the direction of the movable plate 12. Due to the deformation due to the curvature, the curvature at the contact surface 31a 'is relaxed. The deformed correction board 30a 'is indicated by a broken line in FIG. Therefore, the movable mold K2 attached to the auxiliary plate 30a is not deformed. There is no gap between the mold-matching surfaces of the fixed mold K1 and the movable mold K2.

  Since the lower end portion of the fixed platen 11 is fixed to the bed B, and the fixed platen 11 does not move, there is little problem even if the weight is somewhat increased, and it can be constructed from a structure having high rigidity. Therefore, in the embodiment shown in FIG. 1, no correction plate is provided on the fixed platen 11 side. However, it is also possible to provide a correction board having the shape as described above. Even if it is provided on the fixed platen 11 side, the correction plate according to the present embodiment has a simple structure and is inexpensive, so that the production cost of the injection molding machine does not increase. In the embodiment described above, the tie bars 14, 14,... Are inserted into the four corners of the correction panel 30a. However, the tie bars 14, 14,. Furthermore, in the case of a direct pressure type mold clamping device in which hydraulic cylinders are attached to four tie bars, a similar relief portion is also formed on the side portion of the correction panel. These modifications are also applicable to the embodiments described below.

  FIG. 1D shows a second embodiment of the correction board 30b. The same reference numerals are assigned to the same members as those in the above-described embodiment, and the description thereof will not be repeated. However, according to the second embodiment, the upper and lower ends of the correction board 30b are scraped off in a tapered shape. ing. As a result, a relief portion 33b is formed, and the contact surface 31b is smaller than the projection surface of the movable mold K2 with respect to the movable platen 12. Therefore, the same effect can be obtained by the second embodiment.

  FIG. 2 shows an embodiment comprising a correction board main body with a common correction board and an attachment that is selectively detachably attached to the main body. The same reference numerals are given to the same members as those of the above-described embodiment, and the description will not be repeated. However, according to the third embodiment, the correction panel main body 35e is shown in FIG. As shown, a recess 36e for insertion having a predetermined diameter and a predetermined depth is formed on the contact surface 31e side. The attachment 37e attached to the recessed portion 36e for fitting is attached to the mounting portion 38e having a size that fits into the recessed portion 36e for fitting of the correction panel main body 35e, and protrudes from the mounting portion 38e so as to contact the movable platen 12 and "relief". It is formed integrally with the relief portion forming portion 39e constituting the “portion”. The thickness w of the escape portion forming portion 39e is, for example, 0.5 mm. Therefore, when the attachment 37e is attached to the correction board main body 35e and attached to the movable board 12, the shape or size as shown in FIG. The same effect as the first embodiment can be obtained.

  FIG. 2A shows a fourth embodiment in which another attachment 37f having a different size is attached to the correction panel main body 35e. According to the present embodiment, the size of the escape portion forming portion 39f of the attachment 37f is the same as that of the escape portion forming portion 39e of the third embodiment, but the others are the same size. Plural attachments with different sizes and thicknesses of relief parts are prepared, and the most suitable attachment is selected according to the strength of the movable platen, the size of the mold, the size of the clamping force, etc. ing.

DESCRIPTION OF SYMBOLS 1 Injection device 2 Cylinder barrel 10 Clamping device 11 Fixed platen
12 Movable platen 13 Clamping housing
14 Tie bar 20 Toggle mechanism
30a-30f Correction board
33a to 33f Relief part 35e Correction panel body 37e, 37f Attachment

Claims (1)

An injection device for injecting an injection material in a molten state, and a mold clamping device in which the injection material injected from the injection device is injected and filled,
The mold clamping device includes a mold plate, a mold that is attached to the mold plate and has a cavity on a parting surface thereof, and a plurality of tie bars that clamp the mold plate. The mold plate and the mold Between the mold, a correction board is provided which has a substantially plate shape and is formed with a relief portion cut out by a predetermined amount in the thickness direction in the vicinity of an end protruding a predetermined amount from the mold. in it are molding apparatus adapted that,
The correction board comprises a combination of a common correction board main body (35e) and a plurality of attachments (37e, 37f) selectively detachably attached to the main body.
The attachment includes a mounting portion (38e) having a size that fits into the fitting recess (36e) of the correction plate main body (35e), and protrudes from the mounting portion (38e) to come into contact with the mold plate to release a relief portion. An injection molding apparatus comprising: a relief portion forming portion that is configured, wherein each of the relief portion forming portions has a different size, thereby constituting a plurality of attachments .

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