JP2011212880A - Method and device of molding synthetic resin product by split mold - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a device of molding a resin molded product which can stably open/close a mold even at high opening/closing speed of the mold, and obtain higher molding speed and uniform quality of the molded articles.SOLUTION: A fixed side mold body is provided with a cavity plate, a movable side mold body is provided with slide plates mounted with split molds, and mold clamping cams and mold opening cams which open/close the slide plates. Projection of the ejectors and the opening/closing operation of the slide plates are linked, and a separating step of the cavity plate and an opening step of the slide plates fixing the split molds, are separately carried out in opening the mold.

Description

  The present invention relates to a molding method and apparatus for splitting resin products such as synthetic resin caps, and more particularly to a molding method and apparatus for resin products that require a split mold in a molding die.

  Conventionally, synthetic resin caps are molded by injection molding or compression molding, but molding of resin products that have an undercut part and can be damaged without force is generally performed with a split mold. Yes. The mold opening in the molding using the split mold is usually performed by linking the rising of the cavity plate and the opening of the slide plate by the operation of the mold opening cam. That is, the cavity plate to which the upper mold is attached and the slide plate to which the split mold is attached are linked to open and close the mold. Since literature information describing in detail the mold opening technique of the mold apparatus could not be found, a mold opening method and apparatus particularly in a molding apparatus using a split mold which has been conventionally performed in the field of synthetic resin cap molding technology is shown in FIG. Referring to FIG. 6 to 8 show a mold structure of a synthetic resin cap injection molding apparatus as shown in FIG. A synthetic resin cap 70 shown in FIG. 9 is provided via a ceiling wall 71, a skirt wall 72 depending from the outer peripheral edge of the ceiling wall 71, and a circumferential weakening 73 that can be broken at the lower end of the skirt wall. It consists of a tamper evident band 75 having a flap 74 formed on the surface, and the outer peripheral surface of the lower part from the circumferential weakened part 73 is formed using a split mold.

  6 to 8 show a main part of a conventional molding apparatus having a split mold for molding a synthetic resin cap as shown in FIG. 9, FIG. 6 is a plan view seen from the cavity plate surface, and FIG. 6 is a cross-sectional view taken along the line AA in FIG. 6, and FIG. 8 is a cross-sectional view taken along the line BB. 7 (a)-(d) and FIGS. 8 (a)-(d) show cross sections in corresponding states. In a conventional molding apparatus having a split mold, as shown in FIG. 7, a mold opening cam 52 and a locking block 53 (FIG. 8) are fixed to a cavity plate 51 fixed to a stationary mold body 50. A slide plate 57 to which a split mold is fixed is slidably disposed on the stripper plate 56 of the movable mold body 55. Therefore, when the mold is opened, the movable mold body 55 moves downward relative to the fixed mold body 50 from the state (mold closed state) in which the molding shown in FIGS. As shown in (b), the opening of the cavity plate 51 and the opening of the slide plate 57 by the mold opening cam 52 are simultaneously performed by linking, and the mold opening completion state shown in (c) is obtained. Next, as shown in FIG. 8D, when the ejector 58 protrudes, the stripper plate 56 rises, and the molded product is punched (taken out).

  As described above, in a molding apparatus having a conventional split mold, mold opening links the lowering of the movable mold body and the opening of the slide plate 57 by the operation of the mold opening cam 52 provided in the fixed mold body 50. Let's go at the same time. Therefore, in the conventional molding method and apparatus having a split mold, if the mold opening / closing speed is further increased, the slide plate will return as the mold opening / closing speed increases, and the cavity plate rises and the slide plate opens. Does not follow, and the operation becomes unstable, resulting in the problem of hindering the homogenization of the product. On the other hand, in the case of small-sized and mass-produced products such as synthetic resin caps, higher production speed and higher quality are demanded in order to improve productivity. However, in the conventional molding method and apparatus, the problem is that the operation becomes unstable as described above due to the increase in the mold opening / closing speed, and thus the speed is limited and the improvement in productivity is hindered. There is a point.

  Information on prior art documents related to the present invention could not be found.

  Therefore, the present invention is to solve the above-mentioned problem of mold opening when molding a resin molded product that requires a conventional split mold, and the mold opening and closing is stable even when the mold opening and closing speed is increased. It is an object of the present invention to provide a method and apparatus for molding a resin molded product that can increase the molding speed and homogenize the molded product.

The molding method of the resin molded product of the present invention that solves the above problems is a molding method of a resin molded product that requires a split mold, and the mold opening after molding is divided into a fixed mold body and a movable mold body The process and the opening process of the slide plate to which the split mold is fixed are performed separately.
Since the separation process of the fixed mold body and the movable mold body and the opening process of the slide plate to which the split mold is fixed have been separated, the opening and closing of the slide plate can be divided into the fixed mold body and the movable mold body. It can be driven independently, and even when the speed is increased, the slide plate can be opened and closed, that is, the split mold can be opened and closed stably.

  The opening process of the slide plate is performed by a dedicated mold opening cam, and can be stably performed by linking the ejector protrusion and the opening / closing operation of the slide plate. The molding method and apparatus of the present invention is provided with a top wall, a skirt wall depending from the outer peripheral edge of the top wall, and a circumferentially weakened portion that can be broken at the lower end of the skirt wall, and a flap is formed on the inner peripheral surface. The present invention can be suitably applied to molding a synthetic resin cap comprising the tamper evident band.

  A molding apparatus for a resin molded product of the present invention that solves the above problems is a molding apparatus for a resin molded product that requires a split mold, and has a cavity plate in a stationary mold body and a split mold in a movable mold body. A slide plate to which a mold is attached, a mold closing cam for opening and closing the slide plate, and a mold opening cam are provided, and the ejector protrusion and the opening and closing operation of the slide plate are linked.

  The slide plate is slidably provided on the stripper plate, and has a mold opening side inclined surface and a mold closing side inclined surface which are cam follower surfaces that come into contact with the mold closing cam and the mold opening cam. The split mold is configured to be opened and closed by abutment with the cam surfaces of the mold closing cam and the mold opening cam. The molding apparatus for the resin molded product is suitable for a molding apparatus for a synthetic resin cap, and is configured so that a plurality of synthetic resin caps can be molded simultaneously.

  The present invention performs the opening and closing operation of the slide plate to which the split mold is attached with each dedicated cam, and by linking the ejection of the ejector and the opening and closing operation of the slide plate, when the ejector is ejected, the slide plate opens and returns the ejector Since the slide plate is closed, the opening of the cavity plate and the opening of the slide plate can be separated when the mold is opened. Therefore, the mold opening operation of the cavity plate and the opening / closing operation of the split mold are performed in different systems, and the opening / closing operation of the slide plate can be stably performed even when the mold opening / closing speed is increased, and the conventional split mold is provided. The mold can be opened at a higher speed than the mold apparatus, and productivity can be improved.

It is the top view seen from the cavity plate surface of the shaping | molding apparatus which concerns on embodiment of this invention. (A)-(d) is AA sectional drawing of FIG. 1 in order of advancing of a mold opening process. (A)-(d) is BB sectional drawing of FIG. 1 in the advancing order of a mold opening process. It is a principal part enlarged view of FIG. It is the longitudinal cross-sectional schematic of the shaping | molding apparatus which concerns on embodiment of this invention, Each cross section of the opening / closing control part of a cavity part and a slide plate is shown in the right half, and the connection of each plate of a stationary-side metal mold body is shown in the left half The state is shown schematically. It is the top view seen from the cavity plate surface of the shaping | molding apparatus which concerns on a prior art example. (A)-(d) is AA sectional drawing of FIG. 6 in the advancing order of a mold opening process. (A)-(d) is BB sectional drawing of FIG. 6 in the advancing order of a mold opening process. It is sectional drawing of the synthetic resin cap shape | molded by the shaping | molding apparatus which concerns on the said embodiment, and the shaping | molding apparatus of a prior art example.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a method for molding a synthetic resin product using a split mold according to the present invention and an apparatus therefor will be described in detail below with reference to the drawings. The illustrated embodiment shows a molding apparatus in the case of injection molding a synthetic resin cap as shown in FIG.
1 is a plan view of a movable mold body, FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1, FIG. 3 is a cross-sectional view taken along the line BB, FIG. FIG. In the cross-sectional view of FIG. 5, for the sake of clarity, the right half shows cross sections of the cavity portion 7 and the slide plate opening / closing control portion 8, and the left half shows the connection state of the plates of the movable mold body. This is shown schematically. As will be described in detail below, the molding apparatus 1 having the split mold according to the present embodiment is configured such that the cavity plate and the slide plate are interlocked and the mold is opened at the same time. It is characterized by the point where

As shown in FIG. 5, the molding apparatus 1 according to the present embodiment includes a fixed-side mold main body 2 and a movable-side mold main body 3 provided to be movable up and down with respect to the fixed-side mold main body. The movable mold body 3 is driven up and down by a mold drive source (not shown).
In FIG. 5, reference numeral 10 denotes a cavity plate, which is fixed to the fixed-side mold main body 2. A cavity mold 11 is arranged on the cavity plate 10 so as to correspond to the cavity portion 7 shown in FIG. 1, and a nozzle 13 is arranged on each cavity mold 11 through a gate. The cavity plate 10 is integrally fixed with a locking block 15 that engages with a slide plate (to be described later) and fixes its opening when the mold is clamped. In the illustrated embodiment, 24 cavity molds are arranged on the cavity plate so as to mold 4 × 6 caps at a time, but is not limited thereto.

  In the movable mold body 3, a slide plate 17 to which a pair of split molds 16 (see FIGS. 3 and 4) is attached is opened and closed (slided) with respect to the lateral center line L of each cavity in FIG. A stripper plate 18 that is supported in a vertically movable manner is provided by an ejector 19. As the stripper plate 18 moves up and down, the slide plate 17 also moves up and down, and the mold opening cam 20 and the mold closing cam 21 that are engaged with the slide plate 17 and controlled to open and close are fixed to the fixed cam fixing plate 22. ing. As shown in FIG. 2, the slide plate 17 is provided with a pair of cam follower sections with the mold opening cam 20 interposed therebetween, and the inner inclined surfaces 25 that engage with the cam surface of the mold opening cam 20 face each other. The cam surfaces of the slide plate are formed so as to be inclined outward. Further, on the side opposite to the inner inclined surface, an outer inclined surface 26 that engages with the cam surface of the mold closing cam 21 is similarly provided to be inclined outward.

  As shown in FIG. 2, the mold opening cam 20 has a base fixed to a cam fixing plate 22 and has a mold opening cam surface 27 on the upper side thereof. The mold opening cam surface 27 is inclined at the same angle as the inner inclined surface 25 of each pair of slide plates, contacts the inner inclined surface, and the stripper plate 18 is pushed up by an ejector as will be described later, whereby the slide plate 17 2 is moved along the mold opening cam surface, thereby receiving an action of opening left and right in FIG. Similarly to the mold opening cam 20, the mold closing cam 21 has a base fixed to the cam fixing plate 22 and a mold closing cam surface 28 on the upper side thereof. As shown in FIG. 2, the mold closing cam 21 is disposed between adjacent slide plates 17 and outside the outermost slide plate 17, and one mold closing cam 21 disposed between the slide plates 17 is provided on both sides. Mold closing cam surfaces 28 are formed on both sides so as to operate the slide plate 17 adjacent thereto in the mold closing direction. The mold closing cam surface 28 is inclined at the same angle as the outer inclined surface 26 of the slide plate 17 and comes into contact with the outer inclined surface. As will be described later, the slide plate 17 is lowered by the ejector, whereby the outer inclined surface 26 is moved. By moving along the mold closing cam surface 28, it is pressed and closed.

  The shaping | molding apparatus 1 which has a split type | mold which concerns on this embodiment is comprised as mentioned above, and demonstrates a mold opening process based on FIG.2 and FIG.3. 2A to 2D are process diagrams in the AA cross section in FIG. 1, and FIGS. 3A to 3D are cross sections taken along the line BB corresponding to FIGS. 2A to 2D. FIG. (A) in each shows the state just before a product is injection-molded with each metal mold | die in a mold-closed state, and a mold opening is performed. In this state, the movable mold body 3 is in the uppermost position, the cavity plate is pressed against the split mold, the cavity mold, split mold, and core mold form a cavity, and the locking block is fixed to the cavity mold. 15 is pressed against the outer tapered surface of the slide plate 17 to prevent the slide plate from opening. From this state, as shown in (b), when the movable mold body 3 is lowered, the fixed side and the movable side are divided, and the cavity plate 10 is completely separated from the molded product and the mold is opened. In this state, the slide plate 17 is released from the restraint by the locking block 15 but is still kept closed.

  Next, the ejector 19 ascends from the state of (b) and protrudes the stripper plate 18 so that the slide plate 17 rises and the inner inclined surface 25 of the slide plate rises while being pressed along the mold opening cam surface. As a result, the slide plate opens to the left and right, and the split mold opens. (C) is an intermediate view, and (d) shows a state in which the ejection of the ejector is finished, the split mold is completely opened, and the product has been taken out. Since the removal of the molded product is performed by a mechanism similar to that of the conventional mold apparatus, a detailed description thereof is omitted. For example, the knockout rod 29 at the center of the core mold protrudes upward so that the molded product is removed from the core mold. Then, the die is removed by pushing upward, and then the upper surface of each molded product is adsorbed by a sucker or the like (not shown) and discharged to the take-out position.

  On the other hand, the mold closing is performed in the reverse order of the above mold opening. From the state of FIG. 2 and FIG. 3D, when the ejector descends and the stripper plate 18 descends, the stripper plate When the outer inclined surface 26 of the slide plate 17 provided so as to be slidable comes into pressure contact with the mold closing cam surface 28 of the mold closing cam, it slides in the closing direction and the split mold 16 fixed to the slide plate is closed. . In this state, the movable die body is raised so that the cavity plate 10 is pressed against the split mold, and the locking block 15 fixed to the cavity plate 10 is pressed against and fixed to the slide plate to complete the mold closing. To do.

  As described above, in the present invention, the slide plate is opened and closed with dedicated cams, and the ejector protrusion and the slide plate opening and closing operation are linked so that when the ejector is ejected, the slide plate opens, and when the ejector is returned, the slide By adopting a structure in which the plate is closed, it is possible to separate the opening of the cavity plate and the opening of the slide plate during mold opening. Therefore, even if the mold opening / closing speed is increased, the opening / closing operation of the slide plate can be stably performed, and the mold opening can be performed at a higher speed than the conventional mold apparatus having a split mold, thereby improving the productivity. .

  The method and apparatus for molding a synthetic resin product using a split mold according to the present invention can be widely applied not only to a synthetic resin cap but also as a mold apparatus for a resin molded product that requires a split mold, particularly for small articles that require high-speed production. It can be suitably applied to molding.

DESCRIPTION OF SYMBOLS 1 Molding apparatus of resin molded product 2 Fixed side mold main body part 3 Movable side mold main body part 7 Cavity part 8 Opening / closing control part 10 Cavity plate 11 Cavity mold 13 Nozzle 15 Locking block 16 Split mold 17 Slide plate 18 Stripper plate 19 Ejector 20 Mold opening cam 21 Mold closing cam 22 Cam fixing plate 25 Inner inclined surface 26 Outer inclined surface 27 Mold opening cam surface 28 Mold closing cam surface 29 Knockout rod 70 Synthetic resin cap

Claims (6)

  In the molding method for resin molded products that require split molds, mold opening after molding is divided into the split process of the fixed mold body and the movable mold body and the opening process of the slide plate that fixes the split mold. A method for molding a resin molded product, which is performed.   2. The method for molding a resin molded product according to claim 1, wherein the opening step of the slide plate is performed by a dedicated mold opening cam, and the ejector projection and the opening / closing operation of the slide plate are linked.   The resin molded product includes a top wall, a skirt wall depending from the outer peripheral edge of the top wall, a tamper-evident band provided at a lower end of the skirt wall through a circumferential weakened portion, and the tamper-evity. The method for molding a resin molded product according to claim 1 or 2, wherein the molded resin cap is a synthetic resin cap made of a flap formed on the inner peripheral surface of the dento band.   In a molding apparatus for resin molded products that require a split mold, the stationary mold body has a cavity plate, the movable mold body has a slide plate with a split mold, and the mold closing that opens and closes the slide plate. An apparatus for molding a resin molded product, characterized in that a cam and a mold opening cam are provided, and the ejector projection and the opening / closing operation of the slide plate are linked.   The slide plate is slidably provided on the stripper plate, and is formed with a mold opening side inclined surface and a mold closing side inclined surface as a cam follower surface that comes into contact with the mold closing cam and the mold opening cam. The apparatus for molding a resin molded product according to claim 4, wherein the mold closing cam and the mold opening cam are brought into contact with a cam surface of the mold closing cam to open and close the split mold.   The molding device for a resin molded product according to claim 4 or 5, wherein the molding device for the resin molded product is a molding device for a synthetic resin cap, and a plurality of synthetic resin caps can be molded simultaneously.

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