Injection blow molding machine and injection molding system

Abstract

To provide a mold device capable of molding a container-shaped molded product having a protrusion formed on an outer surface of an opening end portion.SOLUTION: There is provided a mold device 101, comprising: an injection molding mold 111 having an injection side concave mold portion 112; a blow molding mold 121 having a blowing-side concave mold portion 122; and an intermediate mold 131 having a convex mold portion 132 that is disposed in the injection side concave mold portion 112 or the blowing side concave mold portion 122 in a mold clamped state. In the clamped state, an injection molding cavity 141 defined between the injection side concave mold portion 112 and the convex mold portion 132 has a shape corresponding to a container-shaped preform 201 having an opening end portion 203, and a blow molding cavity 151 defined between the blowing side concave mold portion 122 and the convex mold portion 132 has a shape corresponding to a container-shaped molded product 211 having an opening end portion 213 with a protrusion 215 formed on the outer surface.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a mold apparatus and an injection molding system used in injection blow molding. [Background technology]

[0002] Injection blow molding is sometimes performed by attaching a predetermined mold device to an injection blow molding machine. The mold device may include an injection mold having an injection-side concave portion, a blow mold having a blow-side concave portion, and an intermediate mold having a convex portion that is placed in the injection-side concave portion or the blow-side concave portion in a clamped state.

[0003] In injection blow molding using an injection blow molding machine, an injection molding cavity is defined between the injection side concave mold part and the convex mold part in a clamped state, and molding material is injected into this injection molding cavity to mold a preform. After that, a blow molding cavity is defined between the blow side concave mold part and the convex mold part in a clamped state, and the preform placed in the blow molding cavity is expanded by supplying a fluid such as air to mold a molded product.

[0004] A related technique is described in, for example, Patent Document 1. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2018-167579 A Summary of the Invention [Problem to be solved by the invention]

[0006] In the above-mentioned injection blow molding, there is a need to be able to mold a container-shaped molded product having a protruding portion, such as a threaded portion, on the outer surface of the open end.

[0007] The present invention is directed to solving these problems, and its object is to provide a mold apparatus and an injection molding system capable of molding a container-shaped molded product having a protrusion formed on the outer surface of the opening end. [Means for solving the problem]

[0008] One mold apparatus capable of solving the above-mentioned problems comprises an injection molding mold having an injection side concave mold portion, a blow molding mold having a blow side concave mold portion, and an intermediate mold having a convex mold portion that is placed in the injection side concave mold portion or the blow side concave mold portion in a mold clamping state, wherein in the mold clamping state, the injection molding cavity defined between the injection side concave mold portion and the convex mold portion has a shape corresponding to a container-shaped preform having an open end, and the blow molding cavity defined between the blow side concave mold portion and the convex mold portion has a shape corresponding to a container-shaped molded product having an open end with a protrusion formed on its outer surface. One injection molding system includes the above-mentioned mold apparatus and an injection blow molding machine to which the mold apparatus is attached. Effect of the Invention

[0009] The above-described mold device makes it possible to mold a container-shaped molded product having a protrusion formed on the outer surface of the open end. [Brief description of the drawings]

[0010] [Figure 1] 1 is a cross-sectional view showing an example of an injection blow molding machine to which a mold device according to an embodiment of the present invention can be attached, together with the mold device. [Diagram 2] 2 is a side view showing a mold open state of the mold device of FIG. 1, and a cross-sectional view taken along line II-II thereof. [Diagram 3] 2 is a side view showing a mold clamping state of the mold device of FIG. 1 and a cross-sectional view taken along line II-II thereof. [Figure 4]1 is a side view showing a molded product and a preform molded by a mold apparatus of one embodiment, with a radial half thereof separated by a central axis cut away. FIG. [Diagram 5] A cross-sectional view along the mold width direction showing the injection side concave portion of an injection molding mold, the blow side concave portion of a blow molding mold, and the convex portion of an intermediate mold provided in a mold apparatus of one embodiment. [Figure 6] 6 is a cross-sectional view taken along the width direction of the mold, showing the injection-side concave mold portion, the blowing-side concave mold portion, and the convex mold portion of the mold device of FIG. 5 in a clamped state and an open state, respectively. [Figure 7] A cross-sectional view along the mold width direction showing the injection side concave portion of an injection molding mold, the blow side concave portion of a blow molding mold, and the convex portion of an intermediate mold provided in a mold apparatus of another embodiment. [Figure 8] 8 is a side view showing a molded product and a preform molded by the mold device of FIG. 7, with a radial half portion separated by a central axis being cut away. [Figure 9] 8 is a cross-sectional view taken along the die width direction, showing a convex portion of an intermediate die provided in the die device of FIG. 7. [Figure 10] 8 is an enlarged cross-sectional view of a main portion of a blow-side concave mold portion of a blow molding mold and a convex mold portion of an intermediate mold provided in the mold apparatus of FIG. 7. [Figure 11] 10 is a cross-sectional view taken along the width direction of the mold, showing a modified example of a convex portion of an intermediate mold of a mold device or a concave portion of an injection side of an injection molding mold. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. The injection blow molding machine 1 illustrated in FIG. 1 is equipped with a mold apparatus 101 according to an embodiment of the present invention, and generally comprises an injection device 21 that melts molding material and injects it into the mold apparatus 101, a moving device 26 that moves the injection device 21 forward and backward relative to the mold apparatus 101, and a mold clamping device 31 that has a fixed platen 32a, a movable platen 32b, and an intermediate mold support frame 32c, and opens and closes the mold apparatus 101 between a mold clamping state and a mold open state.

[0012] The injection blow molding machine 1 is used for injection blow molding. In injection blow molding, a molding material is injected into the injection molding cavity of a mold device 101 to mold a preform, and then a gas such as air or other fluid is supplied to the preform in the blow molding cavity of the mold device 101 to expand the preform and produce a molded product.

[0013] (Molding equipment) The mold apparatus 101 includes an injection molding mold 111 attached to the fixed platen 32a side, a blow molding mold 121 attached to the movable platen 32b side, and an intermediate mold 131 supported by an intermediate mold support frame 32c between the injection molding mold 111 and the blow molding mold 121 and rotated by a rotation shaft portion 41 of the intermediate mold support frame 32c, as shown in Figures 2 and 3.

[0014] When the mold device 101 is attached to the injection blow molding machine 1 in this manner, the injection mold 111 has an injection side concave portion 112 on the surface side facing the intermediate mold 131, as shown in Fig. 2(b). The blow mold 121 has a blow side concave portion 122 on the surface side facing the intermediate mold 131, as shown in Fig. 3(b). The intermediate mold 131 has a convex portion 132 that is disposed in the injection side concave portion 112 or the blow side concave portion 122 in a clamped state, on both sides of the surface facing the injection mold 111 and the surface facing the blow mold 121.

[0015] In the mold clamping state shown in Fig. 3, an injection molding cavity is defined between the injection side concave mold portion 112 and the convex mold portion 132, where a molding material is injected to mold the preform 201. After the preform 201 is molded in the injection molding cavity, the mold device 101 enters a mold open state as shown in Fig. 2, and the convex mold portion 132, while holding the preform 201, is inverted with the rotation of the intermediate mold 131 by the rotary shaft portion 41, and faces the blow molding mold 121. Then, when the mold device 101 enters a mold clamping state again as shown in Fig. 3, a blow molding cavity is defined between the injection side concave mold portion 122 and the convex mold portion 132 holding the preform 201. In the blow molding cavity, the preform 201 is expanded by blowing a fluid from inside thereof, and becomes a molded product 211. When the mold device 101 is in a clamped state, such injection molding and blow molding are performed simultaneously in the injection molding cavity and blow molding cavity defined by the injection side concave mold portion 112 or the blow side concave mold portion 122 and the convex mold portions 132 provided on both sides of the injection molding mold 111 side and the blow molding mold 121 side.

[0016] In the illustrated example, the injection side concave portion 112 of the injection molding die 111, the convex portion 132 of the intermediate die 131, and the blow side concave portion 122 of the blow molding die 121 are each arranged two in the die width direction and six in the height direction (the up and down direction in Figures 2(a) and 3(a)), totaling twelve, but the numbers can be changed as appropriate.

[0017] According to the mold device 101 of this embodiment, it is possible to mold a molded product 211 having a cylindrical container shape with a bottom as shown in Fig. 4(a). This molded product 211 is obtained through a preform 201 having a cylindrical container shape with a bottom as shown in Fig. 4(b).

[0018] More specifically, the molded product 211 shown in Fig. 4(a) has a cylindrical main body 212 such as a cylinder, an open end 213 located at one end side in the axial direction (left and right direction in Fig. 4) of the cylindrical main body 212 and open, and a sealed end 214 located at the other end side in the axial direction of the cylindrical main body 212 and sealed by a bottom 214a. A protruding part 215 having a shape such as a spiral that protrudes from the outer surface and extends in the axial direction while rotating in the circumferential direction on the outer surface is formed on the outer surface of the open end 213. When the protruding part 215 is formed in a spiral shape, it becomes possible to attach and detach a cap (not shown) having a corresponding spiral groove on the inner surface by screwing the cap onto the open end 213.

[0019] In this molded product 211, the cylindrical main body 212 includes a cylindrical trunk 212a such as a cylinder having a constant inner and outer diameter continuing from the closed end 214, and a tapered portion 212b whose inner and outer diameters gradually decrease toward the open end 213 and connects the trunk 212a to the open end 213. A ring-shaped flange 216 such as a ring included in the above-mentioned protruding portion 215 is formed in a portion of the open end 213 closer to the tapered portion 212b. Note that the outermost end on the axial direction outside the open end 213 is a build-up portion 217 that is slightly thicker than the open end 213 and slightly protrudes toward the outer periphery, but this build-up portion 217 is not considered to be the protruding portion 215. Here, the region from the flange portion 216 to just before the outermost end on one end side in the axial direction is the open end 213. As long as the protruding portion 215 is formed on the outer surface of the open end 213, the molded product 211 may have any other shape.

[0020] As shown in Fig. 4(b), the preform 201 used in the blow molding to obtain the molded product 211 has a cylindrical main body 202 whose inner and outer diameters gradually increase toward one axial end, an open end 203 located at one axial end of the cylindrical main body 202 and opening, and a closed end 204 located at the other axial end of the cylindrical main body 202 and closed by a bottom 204a. In this preform 201, too, a cladding portion 207 is present at the outermost end of the open end 203, which is the outermost end in the axial direction, but the cladding portions 217 and 207 of the molded product 211 and the preform 201 may be omitted. The outer surface of the open end 203 of this preform 201, which does not include the cladding portion 207, is formed smoothly.

[0021] More specifically, the mold device 101 capable of molding the preform 201 and molded product 211 as described above has an injection mold 111, a blow mold 121, and an intermediate mold 131, each having a structure shown in FIG. 5. In the mold device shown in FIG. 5, when the mold is clamped, as shown in the same figure and FIG. 6(a), the convex mold part 132 on one surface side of the intermediate mold 131 is inserted and arranged in the injection side concave mold part 112 of the injection mold 111, and an injection molding cavity 141 is defined between them. At this time, the convex mold part 132 on the other surface side of the intermediate mold 131 is inserted and arranged in the blow side concave mold part 122 of the blow molding mold 121, and a blow molding cavity 151 is defined there. Note that the preform 201 and the molded product 211 are not shown here.

[0022] The injection molding cavity 141 is a space having a shape corresponding to the shape of the container-shaped preform 201 having the open end 203 described above. The blow molding cavity 151 is a space having a shape corresponding to the shape of the container-shaped molded product 211 having the open end 213 with the protruding portion 215 formed on the outer surface, also as described above.

[0023] 5 and 6, a recess 123 corresponding to the protrusion 215 is formed on the inner peripheral surface of the blow-side concave portion 122 which corresponds to the outer surface of the molded article 211 in the blow molding cavity 151, at a location corresponding to the outer surface of the opening end 213 of the molded article 211. As a result, when the preform 201 held around the convex portion 132 in the blow molding cavity 151 expands due to the supply of fluid and is pressed against the inner peripheral surface of the blow-side concave portion 122, the recess 123 forms a protrusion 215 having a shape corresponding to the shape of the recess 123 on the outer surface of the opening end 213 of the molded article 211. In this example, in order to form a spiral protrusion portion 215 on the outer surface of the opening end 213 of the molded product 211, a spiral recess portion 123 extending on the inner surface of the blowing side concave portion 122 is provided on the inner surface of the blowing side concave portion 122 to correspond to the protrusion portion 215.

[0024] The structure and shape of each mold of the mold device 101 can be changed as appropriate, but in the illustrated example, the injection molding mold 111 has a mold body 113 and a concave partition member 114 inserted and attached to the surface side of the mold body 113 facing the intermediate mold 131, as shown in FIG. 5. The concave partition member 114 has a bottomed cylindrical shape with a larger inner and outer diameter at the part exposed from the mold body 113 than the part inserted into the mold body 113. The injection side concave portion 112 is provided inside this concave partition member 114. The surface area of ​​the inner peripheral surface of the injection side concave portion 112 corresponding to the outer surface of the opening end 203 of the preform 201 is formed smoothly. The concave partition member 114 provided with the injection side concave portion 112 does not have a split mold. The injection side concave mold portion 112 is connected to the nozzle 22b of the cylinder 22 of the injection device 21 through a gate 115 provided at the deepest part of the injection side concave mold portion 112 in the concave mold partitioning member 114. As a result, during injection molding, molten molding material is supplied from the cylinder 22 to an injection molding cavity 141 defined in the injection side concave mold portion 112.

[0025] The intermediate mold 131 has a core seat 131a, such as a plate-like one, attached to the rotating shaft portion 41, an annular base portion 134 provided on the core seat 131a, and a protruding portion 135, which is inserted into and attached to the base portion 134, protrudes from the base portion 134, and has an outer diameter that gradually decreases toward the tip. The protruding portion 135 has a curved tip surface. The base portion 134 and the protruding portion 135 form the convex portion 132. 5, in the mold clamped state, step portion 114a on the inner periphery of the portion of concave partitioning member 114 exposed from mold body 113 is aligned with step portion 134a on the outer periphery of base 134 of intermediate mold 131. Also, here, a space that forms build-up portion 207 of preform 201 is defined between annular groove portion 136 provided on the surface of base 134 facing injection mold 111 and step portion 114a of concave partitioning member 114.

[0026] In this embodiment, the blow molding die 121 has a split die 124 that can be opened and closed in the die width direction. This allows the molded product 211, which has a larger bottom 214a in the axial direction, to be easily removed from the blow-side concave portion 122. A split die opening / closing mechanism 62, which will be described later, defines a blow-side concave portion 122 having a shape corresponding to the outer shape of the molded product 211 inside the closed split die 124 as shown in Figures 5 and 6. A step portion 124a that matches the step portion 134a of the base 134 is provided at a portion of the split die 124 that comes into contact with the base 134 of the intermediate die 131 in the clamped state.

[0027] In the above-described mold device 101, during blow molding, the opening end 203 of the preform 201 is pressed against a recessed portion 123 provided on the inner peripheral surface of the blow-side concave mold portion 122 by supplying a fluid to the inside of the opening end 203, as shown in Fig. 5, to form a protruding portion 215 of the opening end 213 of the molded product 211. At this time, a part of the molding material of the opening end 203 of the preform 201 fills the recessed portion 123, which may cause a sink mark that is a recess from the inner surface of the opening end 213 of the molded product 211. Such a molded product 211 may have insufficient strength at the opening end 213 where a cap or the like may be attached, resulting in poor quality.

[0028] In order to suppress this, as in the embodiment shown in Fig. 7, it is preferable to provide a thickening space 342 in the injection molding cavity 341, which is a space that is partially wider at least in a part corresponding to the opening end 403 of the preform 401 shown in Fig. 8(b). Due to the thickening space 342, the preform 401 molded in the injection molding cavity 341 has a thickened part 408 that is partially thicker at at least a part of the opening end 403 than other parts such as the cylindrical main body part 402. When blow molding is performed using this preform 401, in the blow molding cavity 351, a part of the molding material of the opening end 403 of the preform 401 is filled into the recessed part 323 of the blow-side concave part 322, but since the extra thick part 408 is formed at the opening end 403, the occurrence of sink marks on the inner surface of the opening end 413 is suppressed in the molded product 411 obtained thereafter. As a result, insufficient strength and quality defects at the opening end 413 of the molded product 411 can be effectively prevented.

[0029] In the embodiment shown in Fig. 7, in order to provide the thick-walled space 342 as described above, a concave portion 337 recessed from the outer circumferential surface is formed at a portion of the outer circumferential surface of the convex portion 332 (more specifically, the protruding portion 335) of the intermediate mold 331 corresponding to the opening end 403 of the preform 401, as shown in an enlarged view in Fig. 9. Providing the thick-walled space 342 by forming the concave portion 337 on the convex portion 332 side in this manner is preferable in that there is no risk of undercutting the preform 401 held by the convex portion 332 on the intermediate mold 331 side when the injection mold 311 moves from a clamped state to a mold open state in which the intermediate mold 331 is separated from the intermediate mold 331. In this preform 401, a thick-walled portion 408 including a protruding portion 409 protruding from its inner surface is formed at the opening end 403.

[0030] Although it depends on the shape of the protruding portion 415 provided on the outer surface of the opening end 413 of the molded product 411, it is preferable that the concave portion 337 is formed over the entire circumference on the outer circumferential surface of the convex portion 332. This makes it possible to effectively prevent the occurrence of sink marks on the inner surface of the opening end 413 of the molded product 411 over the entire circumference.

[0031] Here, a spiral concave portion 337 that extends in the axial direction while rotating in the circumferential direction on the outer surface is formed on the outer peripheral surface of the convex mold portion 332 of the intermediate mold 331 in correspondence with a protrusion portion 415 such as a spiral screw portion provided on the outer surface of the opening end 413 of the molded product 411. In this case, a spiral protrusion 409 is formed on the inner surface of the thick portion 408 of the opening end 403 of the preform 401. The thick portion 408 including such a spiral protrusion 409 provides good filling of the molding material into the spiral recessed portion 323 of the blow-side concave mold portion 322 during blow molding in the blow molding cavity 351, and functions to more effectively suppress the occurrence of sink marks on the inner surface of the opening end 413 of the molded product 411. In this example, in addition to the spiral concave portion 337 described above, the outer peripheral surface of the convex portion 332 also has a tubular flange portion 416 provided on the outer surface of the opening end 413 of the molded product 411, and a corresponding annular concave portion corresponding to the annular recess portion of the blowing side concave portion 322.

[0032] Regarding the position of the concave portion 337 when the concave portion 337 is provided on the outer peripheral surface of the convex mold portion 332, it is preferable that the formation region Rp of the concave portion 337 on the outer peripheral surface of the convex mold portion 332 and the formation region Rd of the recessed portion 323 on the inner peripheral surface of the blow-side concave mold portion 322 overlap at least partially in the axial direction (left and right direction in FIG. 10) in the blow molding cavity 351 as shown in an enlarged view in FIG. 10. This is because the recessed portion 323 of the blow-side concave mold portion 322 can be effectively filled with the molding material by the raised portion 409 formed on the outer surface of the opening end 403 of the preform 401 by the recessed portion 337 of the convex mold portion 332. More preferably, in the axial direction of the blow molding cavity 351, a concave portion 337 is provided on the outer circumferential surface of the convex mold portion 332 in a forming area Rp equal to or larger than the forming area Rd of the recessed portion 323 of the blow-side concave mold portion 322 so as to cover the entirety of the forming area Rd. Other dimensions such as the depth of the recessed portion 337 of the convex mold portion 332 can be appropriately determined depending on the protrusion 415 provided on the opening end 413 of the molded product 411, the dimensions of the recessed portion 323 of the blow-side concave mold portion 322, etc.

[0033] 7 has a spiral concave portion 337 on the outer circumferential surface of the convex portion 332, but the shape of the concave portion 337 is not limited to this. For example, in the convex portion 532 shown in FIG. 11(a), a ring-shaped concave portion 537 is provided on the outer circumferential surface of the convex portion 532, which is recessed over a certain area in the axial direction and goes around in the circumferential direction at a location corresponding to the inner surface of the open end of the preform. Such a concave portion 537 may provide a wall thickness forming space 542. Although not shown in the figures, it is possible to provide various protrusions, not just spiral ones, on the outer peripheral surface of the opening end of the molded product, and the shape of the recessed portion formed in the blowing side concave mold portion can be changed accordingly.

[0034] Also, instead of or in addition to forming a concave portion on the outer circumferential surface of the convex mold portion, as shown in Fig. 11(b), a concave portion 637 of any shape can be formed on the inner circumferential surface of the injection side concave mold portion 612 of the injection molding die 611. This also results in the injection molding cavity having a thick-wall forming space 642, making it possible to form a thick-walled portion in the preform.

[0035] The above-described mold apparatus 101 can be attached to the injection blow molding machine 1 and replaced as appropriate depending on the shape of the molded product to be manufactured, etc. For this reason, the mold apparatus 101 is not included in the injection blow molding machine 1 and is considered to be a separate device from the injection blow molding machine 1. A system including the injection blow molding machine 1 and the mold apparatus 101 attached to the injection blow molding machine 1 is referred to as an injection molding system here.

[0036] (mold clamping device) The mold apparatus 101 as described above is attached to the mold clamping device 31 of the injection blow molding machine 1. The mold clamping device 31 has a mold holding mechanism 32 having a fixed platen 32a, a movable platen 32b, and an intermediate mold support frame 32c, an intermediate mold moving mechanism 61 which moves the intermediate mold support frame 32c relative to the fixed platen 32a, a platen moving mechanism 33 which moves the movable platen 32b relative to the fixed platen 32a, and a split mold opening / closing mechanism 62 which opens and closes the split mold 124 of the blow molding mold 121. The intermediate mold moving mechanism 61 and the split mold opening / closing mechanism 62 will be described later with reference to FIGS. 2 and 3.

[0037] The mold holding mechanism 32 includes a fixed platen 32a located between the injection unit 21 and the mold unit 101, a movable platen 32b located between the fixed platen 32a across the mold unit 101 and capable of moving toward and away from the fixed platen 32a, and an intermediate mold support frame 32c located between the fixed platen 32a and the movable platen 32b and capable of moving toward and away from the fixed platen 32a. The mold clamping unit 31 is also provided with one or more tie bars 32d extending from the fixed platen 32a toward a rear platen 34 (described later) and connecting the fixed platen 32a and the rear platen 34. In this example, the movable platen 32b and the intermediate mold support frame 32c are guided by the tie bars 32d in their moving toward and away from the fixed platen 32a, but there are also cases where they are not guided by the tie bars 32d.

[0038] Of the mold holding mechanism 32, the fixed platen 32a is fixedly attached to the base frame 2. On the other hand, the movable platen 32b and the intermediate mold support frame 32c are each disposed on a guide member 32e laid on the base frame 2, and can slide independently of each other in a direction away from and toward the fixed platen 32a.

[0039] At a position where the movable platen 32b and the intermediate mold support frame 32c are separated from the fixed platen 32a, the blow molding die 121 and the intermediate mold 131 of the mold device 101 are in a mold open state in which they are open from the injection molding die 111. By moving the movable platen 32b and the intermediate mold support frame 32c toward the fixed platen 32a from this separated position, the blow molding die 121 and the intermediate mold 131 are in a mold closed state in which they are closed against the injection molding die 111, and by further moving the movable platen 32b and the intermediate mold support frame 32c toward the fixed platen 32a, the blow molding die 121 and the intermediate mold 131 are in a mold clamped state in which they are pressed against the injection molding die 111. Here, the direction approaching the fixed platen 32a to which the injection molding die 111 of the mold device 101 is attached is the front side, and the direction moving away from the fixed platen 32a is the rear side. For most parts of the mold clamping unit 31 except for the fixed platen 32a, the right side in FIG. 1, approaching the fixed platen 32a, is the front side, and the left side, away from the fixed platen 32a, is the rear side.

[0040] The illustrated intermediate mold support frame 32c has a frame shape such as a rectangle when viewed from the front, and is provided with a rotating shaft portion 41 that is rotatably mounted and extends in the mold width direction (vertical direction in Figs. 2(b) and 3(b)) perpendicular to the front-rear direction in a plane parallel to the horizontal plane. The intermediate mold 131 is attached to the rotating shaft portion 41 and supports it. In this example, the axial direction of the rotating shaft portion 41 is parallel to the horizontal direction, but the axial direction of the rotating shaft portion is not limited to this, and can be, for example, parallel to the vertical direction. A vertical injection blow molding machine may also be used.

[0041] Further, the intermediate mold support frame 32c is provided with an intermediate mold rotation mechanism that rotates the rotation shaft portion 41 and rotates the intermediate mold 131 therewith. Although not shown, this intermediate mold rotation mechanism can be a motor or the like provided on the intermediate mold support frame 32c. Note that a cylindrical member 42 is provided around the rotation shaft portion 41 between the intermediate mold 131 and the intermediate mold support frame 32c.

[0042] The intermediate mold moving mechanism 61 that moves the intermediate mold support frame 32c relative to the fixed platen 32a can be configured with hydraulic cylinders 61a and piston rods 61b that are attached to the fixed platen 32a and the intermediate mold support frame 32c, respectively, and operated by a hydraulic pump driven by a motor, as shown in Figures 2 and 3. In this example, two pairs of hydraulic cylinders and piston rods are provided that are located outside the injection molding die 111 and the intermediate mold 131 in the die width direction, but one pair or three or more pairs may be provided. Although not shown, the intermediate mold moving mechanism may move the intermediate mold support frame forward and backward relative to the movable platen by attaching hydraulic cylinders or the like to the movable platen instead of the fixed platen.

[0043] As shown in FIG. 1, the platen movement mechanism 33 of the mold clamping device 31 includes a rear platen 34 arranged on the base frame 2, a mold clamping motor 35 provided on the rear platen 34, a motion conversion mechanism 36 that converts the rotational motion of the mold clamping motor 35 into linear motion in the displacement direction of the movable platen 32b, and a toggle mechanism 37 that amplifies the force transmitted to the motion conversion mechanism 36 and transmits it to the movable platen 32b.

[0044] Among these, the motion conversion mechanism 36 can be various mechanisms capable of converting rotary motion into linear motion, but in this example, it is configured to include a screw shaft 36a rotated by the mold clamping motor 35 and a nut 36b screwed onto the screw shaft 36a. The motion conversion mechanism 36 can also be a ball screw. The toggle mechanism 37 for increasing the transmission force from the motion conversion mechanism 36 is formed by connecting a plurality of links 37a to 37c connecting the nut 36b of the motion conversion mechanism 36 and the movable platen 32b with joints so as to be swingable. The number and shapes of the links and joints can be appropriately changed, but as shown in FIG. 1, a pair of link groups consisting of the links 37a to 37c located above and below the crosshead 37d are swingably connected to a crosshead 37d connected to the nut 36b and extending in the vertical direction.

[0045] In addition to the above-mentioned mold clamping motor 35, a mold thickness adjustment motor 38 can also be provided on the rear platen 34. This mold thickness adjustment motor 38 functions to adjust the interval between the fixed platen 32a and the rear platen 34 movably mounted on the base frame 2 by applying a rotational driving force to a screw shaft and a nut connected to an extension portion of each tie bar 32d of the above-mentioned mold holding mechanism 32. This makes it possible to adjust the mold thickness so that a desired mold clamping force can be applied to the mold device 101 even when the mold device 101 is replaced or the thickness of the mold device 101 is changed due to a temperature change. Although not shown in the figure, the mold thickness can be adjusted even if the fixed platen side is made movable on the base frame 2 and the rear platen side is fixed.

[0046] 2 and 3, the mold clamping device 31 is equipped with a split mold opening / closing mechanism 62 which has a piston rod 62a, a hydraulic cylinder 62b, etc., and which drives a split mold 124 of the blow molding mold 121 to advance and retreat in the mold width direction to open and close it. The split molds 103b of the blow molding mold 121 which are moved in the same direction in the mold width direction by the split mold opening / closing mechanism 62 can be connected to each other by split mold connecting members 63a, 63b.

[0047] The illustrated mold clamping unit 31 is of a horizontal type in which the moving direction of the movable platen 32b is parallel to the horizontal direction, but it may also be of a vertical type in which the moving direction is vertical.

[0048] (injection device) The injection device 21 mainly includes a cylinder 22 having a cylindrical shape or the like extending toward the mold device 101, a screw 23 arranged inside the cylinder 22 with its central axis parallel to the cylinder 22 and with flights spirally provided around it, a heater 24 having a band shape or the like arranged around the outer periphery of the cylinder 22, and a motor box 25 arranged behind the cylinder 22 and the screw 23. Although not shown in the figure, the motor box 25 includes a metering motor that rotates the screw 23 around the central axis to accumulate a predetermined amount of molding material at the tip of the cylinder 22, an injection motor that moves the screw 23 forward and backward in each direction, toward and away from the mold device 101, and a pressure detection sensor that detects the pressure that the screw 23 receives from the molding material, and the like.

[0049] In this case, the direction approaching the fixed platen 32a of the mold clamping unit 31 to which the injection molding die 111 of the mold apparatus 101 is attached is defined as the front side, and the direction moving away from the fixed platen 32a is defined as the rear side. Therefore, in the case of the injection unit 21 located to the right of the fixed platen 32a in FIG. 1, the left direction approaching the fixed platen 32a is the front side, and the right direction moving away from the fixed platen 32a is the rear side.

[0050] The cylinder 22 is provided with a supply port 22a, to which a hopper for feeding molding material into the cylinder 22 can be attached, in front of the motor box 25 on the rear side. A nozzle 22b, the cross-sectional area of ​​which decreases on the front side, is provided at the tip of the cylinder 22 close to the mold device 101. A water-cooled cylinder 22c for cooling with water or the like can be provided near the supply port 22a.

[0051] The heater 24 disposed around the cylinder 22 including the nozzle 22b may be divided into a plurality of parts in the cylinder axial direction as shown in the figure, so that the inside of the cylinder 22 inside each heater part can be heated at different temperatures. Each heater part may be provided with a temperature detector.

[0052] A backflow prevention ring (not shown) may be disposed around a constricted portion formed by partially reducing the outer diameter of the tip of the screw 23 to prevent the molding material, which has been sent forward and backward together with the screw 23, from flowing backward toward the rear. This backflow prevention ring displaces back and forth relative to the screw 23 in response to the pressure it receives from molding material located forward or backward from it, thereby allowing only the flow of molding material from the rear to the front.

[0053] According to the injection device 21 having such a configuration, the molding material fed into the inside of the cylinder 22 from the supply port 22a is heated by the heater 24 on the outer periphery of the cylinder 22 and melted by the rotation of the screw 23 driven by the metering motor, while being sent forward inside the cylinder 22 and accumulated at the tip of the cylinder 22. At this time, the screw 23 is displaced backward by the injection motor to form a space at the tip of the cylinder 22 in which the molding material is accumulated.

[0054] Thereafter, by displacing the screw 23 forward, the molding material at the tip of the cylinder 22 is injected toward the mold device 101 through the nozzle 22b. Further thereafter, pressure is applied to the molding material filled in the cavity of the mold device 101 through the molding material remaining at the tip of the cylinder 22, thereby performing pressure dwell. At this time, it is possible to replenish the molding material that has become insufficient in the injection molding cavity of the mold device 101 due to cooling contraction of the molding material.

[0055] Although this injection blow molding machine 1 is an in-line screw type, it can also be a pre-plasticization type injection molding machine in which the plasticizing cylinder and plasticizing screw are structurally and functionally separated from the injection cylinder and injection plunger.

[0056] (Mobile device) The moving device 26 is provided, for example, below the motor box 25 of the injection device 21, and is an advance / retract drive mechanism for moving the injection device 21 forward and backward relative to the fixed platen 32a. Various mechanisms can be adopted as the forward and backward drive mechanism that constitutes the moving device 26, but the moving device 26 shown in the figure is configured to include a hydraulic pressure pump 27 or the like, a pump operation motor 28, which is electric or the like, that operates the hydraulic pump 27, and a double-acting hydraulic cylinder 29 that is supplied with hydraulic fluid from the hydraulic pump 27 and causes a piston rod, the tip of which is fixed to a fixed platen 32a, to perform an extrusion and retraction motion.

[0057] The moving device 26 further includes a slide base 26a to which the above-mentioned hydraulic pump 27, pump actuation motor 28, and hydraulic cylinder 29 are attached, and a guide 26b that is laid on the base frame 2 to guide the linear motion of the slide base 26a. This realizes forward and backward displacement of the injection device 21 placed on the upper part of the slide base 26a.

[0058] The moving device 26 makes it possible to move the injection device 21 away from the mold device 101, or to move the injection device 21 closer to the mold device 101 and press the nozzle 22b of the cylinder 22 of the injection device 21 against the mold device 101 with a predetermined pressure, thereby performing a so-called nozzle touch.

[0059] (Operation of injection molding machine) The injection blow molding machine 1 described above operates to carry out the following steps. With the mold device 101 in the mold open state shown in Figure 2, a mold closing process is performed in which the platen moving mechanism 33 moves the movable platen 32b toward the fixed platen 32a, and the intermediate mold moving mechanism 61 moves the intermediate mold support frame 32c toward the fixed platen 32a.

[0060] Next, with a predetermined amount of molding material already stored and arranged inside injection unit 21 by measuring during the previous molding, which will be described later, a clamping process is performed in which mold unit 101 is clamped using clamping unit 31, as shown in Fig. 3. In the clamping process, injection molding cavity 141 is defined between injection molding die 111 and intermediate die 131, and blow molding cavity 151 is defined between blow molding die 121 and intermediate die 131.

[0061] Then, the screw 23 advances to inject the molding material toward the injection molding cavity 141 of the mold device 101, and an injection process is performed in which the molding material is filled into the injection molding cavity 141. In the injection process, after the molding material is filled into the injection molding cavity 141, the screw 23 advances further to hold the molding material inside the tip of the injection device 21 at a predetermined pressure. Thereafter, the molding material filled into the injection molding cavity 141 is cooled and solidified. As a result, the preform 201 is molded in the injection molding cavity 141. At this time, the molding material separately charged into the injection device 21 is melted while being sent toward the tip of the injection device 21 by the rotation of the screw 23 under heating by the heater 24, and a predetermined amount of the molding material is measured and placed at the tip.

[0062] In parallel with the above-mentioned injection process, a blowing process is carried out in the blow molding cavity 151. A preform 201 that has already been molded in the injection molding cavity 141 before the intermediate mold 131 is inverted is placed in the blow molding cavity 151. In the blowing process, a fluid such as air or other gas is supplied to the preform 201, causing the preform 201 to expand in the blow molding cavity 151, thereby molding a molded product 211.

[0063] Thereafter, the platen moving mechanism 33 and the intermediate mold moving mechanism 61 of the mold clamping device 31 are operated to move the movable platen 32b and the intermediate mold support frame 32c away from the fixed platen 32a, and the mold opening process is performed to open the mold device 101.

[0064] After the mold opening step, the split mold opening / closing mechanism 62 is used to open the split mold 124 of the blow molding die 121 to remove the molded product 211, and then the split mold opening / closing step is performed to close the split mold 124 of the blow molding die 121. Also, here, an intermediate mold rotating step is performed in which the intermediate mold 131 is inverted by the intermediate mold rotating mechanism. As a result, the convex mold portion 132 of the core mold of the intermediate mold 131 on the side from which the molded product 211 was collected in the split mold opening and closing step faces the injection side concave mold portion 112 of the injection molding die 111. On the other hand, the convex mold portion 132 of the core mold of the intermediate mold 131 on the side from which the preform 201 was molded in the injection step faces the blow side concave mold portion 122 of the blow molding die 121 while holding the preform 201. The intermediate mold rotating step can be performed at approximately the same time as the split mold opening and closing step, or before or after the split mold opening and closing step.

[0065] In injection molding using the injection blow molding machine 1, the above-mentioned mold closing process, mold clamping process, injection process, blowing process, mold opening process, split mold opening / closing process, and intermediate mold rotating process are repeatedly performed. [Explanation of symbols]

[0066] 1 Injection blow molding machine 2 Base frame 21 Injection device 22 cylinders 22a Supply port 22b Nozzle 22c water-cooled cylinder 23 Screw 24 Heater 25 Motor box 26 Mobile Devices 26a Slide Base 26b Guide 27 Hydraulic Pump 28 Pump operating motor 29 Hydraulic Cylinder 31 Mold clamping device 32 Die holding mechanism 32a Fixed Platen 32b Movable platen 32c Intermediate mold support frame 32d tie bar 32e Guide member 33 Platen movement mechanism 34 Rear platen 35 Clamping motor 36 Motion conversion mechanism 36a Screw shaft 36b Nut 37 Toggle Mechanism 37a~37c Link 37d Crosshead 38 Die thickness adjustment motor 41 Rotating shaft 42 Cylindrical member 61 Intermediate mold moving mechanism 61a Hydraulic cylinder 61b Piston rod 62 Split mold opening and closing mechanism 62a Piston rod 62b Hydraulic cylinder 63a, 63b Split type connecting member 101 Mold equipment 103b split mold 111, 311, 611 Injection mold 112, 312, 612 Concave part on injection side 113, 313 type main body 114, 314 Concave partition member 114a Step Gates 115 and 315 121, 321 Blow mold 122, 322 Concave part on blowing side 123, 323 recessed part 124, 324 split type 124a Step 131, 413 Intermediate mold 131a, 331a Core 132, 332, 532 Convex part 134, 334 base 134a Step 135, 335 protrusion 136 Annular groove 337, 537, 637 concave part 141, 341 Injection molding cavity 342, 542, 642 Wall thickness forming space 151, 351 Blow Molding Cavity 201, 401 Preform 202, 402 Cylindrical main body 203, 403 Open end 204, 404 Sealed end 204a, 404a bottom 207, 217 Overlay part 211, 411 Molded products 212, 412 Cylindrical body 212a Torso 212b Tapered section 213, 413 Open end 214, 414 Sealed end 214a, 414a bottom 215, 415 protrusion part 216, 416 flange section Rd: The area where the recessed portion is formed on the injection side Rp Concave part formation area in the convex part

Claims

1. an injection molding die having an injection side concave portion; A blow molding die having a blow-side concave portion; an intermediate mold having a convex mold portion that is arranged in the injection side concave mold portion or the blowing side concave mold portion in a mold clamping state; A die assembly comprising: In a mold clamping state, the injection molding cavity defined between the injection side concave mold portion and the convex mold portion has a shape corresponding to a container-shaped preform having an open end, and the blow molding cavity defined between the blow side concave mold portion and the convex mold portion has a shape corresponding to a container-shaped molded product having an open end with a protrusion formed on its outer surface.

2. 2. The mold apparatus according to claim 1, wherein the inner peripheral surface of the blowing-side concave mold portion has a recessed portion corresponding to the protruding portion at a location corresponding to the outer surface of the opening end of the molded product.

3. 3. The mold apparatus according to claim 1, wherein the injection molding cavity has a wall-thickening space for partially increasing the thickness of the open end of the preform at least in a portion thereof.

4. 4. A mold apparatus according to claim 3, wherein the outer peripheral surface of the convex mold portion has a concave portion recessed from the outer peripheral surface at a location corresponding to the inner surface of the open end of the preform.

5. The mold apparatus according to claim 4, wherein the concave portion is formed over the entire outer periphery of the convex portion.

6. 6. A mold apparatus according to claim 4, wherein the recessed portion is spirally extending on the inner peripheral surface of the blowing-side concave mold portion, and the concave portion is spirally extending on the outer peripheral surface of the convex mold portion.

7. A mold apparatus described in any one of claims 4 to 6, wherein in the blow molding cavity, the formation area of ​​the concave portion on the outer peripheral surface of the convex mold portion and the formation area of ​​the recessed portion on the inner peripheral surface of the blow-in side concave mold portion overlap in at least a portion of the axial direction.

8. 8. A mold apparatus according to claim 4, wherein the surface area of ​​the inner circumferential surface of the injection side concave mold portion, which corresponds to the outer surface of the open end of the preform, is smooth.

9. 9. The mold apparatus according to claim 1, wherein, among the injection mold, the blow mold and the intermediate mold, only the blow mold has a split mold.

10. An injection molding system comprising: the mold apparatus according to any one of claims 1 to 9; and an injection blow molding machine to which the mold apparatus is attached.

Images