Mold device

Abstract

To provide a mold device capable of molding a molded product with high precision.SOLUTION: A mold device 10 includes a cavity 11 between a fixed mold 20 and a movable mold 40 into which a molding material is filled. The mold device 10 includes: a first positioning mechanism 13 that positions the fixed mold 20 and the movable mold 40 before a filling step in which the molding material is filled; and a second positioning mechanism 14 that positions the fixed mold 20 and the movable mold 40 in a compression step in which the molding material is compressed. A ring member 51 provided on one of the fixed mold 20 and the movable mold 40 has a wall surface 516 that constitutes a part of the cavity 11, and moves relative to the movable mold in a direction parallel to a flow direction of the molding material toward a flow end of the cavity 11.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a mold apparatus. [Background technology]

[0002] Conventionally, when forming a molded product by injection molding, a compression molding method is known in which a filling step of filling a molding material and a compression step of compressing the filled molding material are carried out in this order. Specifically, before the filling step, an injection molding machine places a movable mold of a mold device in a position slightly retreated from a mold clamping position to enlarge the cavity of the mold device, and injects the molding material in the filling step. In the subsequent compression step, the injection molding machine advances the movable mold to the mold clamping position to compress the previously filled molding material, causing the molding material to flow and form a molded product.

[0003] The above compression molding method is applied, for example, when manufacturing a thin-walled molded product. However, when molding a thin-walled molded product, problems such as the pressure of the molding material not reaching the flow end of the cavity due to misalignment between the fixed mold and the movable mold tend to occur. As a result, the molding material may solidify midway, causing uneven thickness (uneven thickness) in the molded product.

[0004] Patent document 1 discloses a mold apparatus equipped with a positioning mechanism (insert ring, insert ring storage groove) that positions the fixed mold and the movable mold before the filling process in order to suppress misalignment between the fixed mold and the movable mold. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2004-174714 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, the positioning mechanism disclosed in Patent Document 1 serves to position the fixed mold and the movable mold in both the filling process and the compression process. In this case, the mold device has problems such as the insert ring being seized during positioning or low positioning accuracy.

[0007] For example, when a tapered portion is used in the positioning mechanism for the fixed and movable dies, if the positioning accuracy is guaranteed in the filling step, the distance between the dies will be further reduced in the compression step, causing galling. Conversely, if the positioning accuracy is guaranteed in the compression step, the positioning accuracy of the positioning mechanism will be reduced in the filling step, causing thickness deviation and reducing the dimensional accuracy of the molded product.

[0008] The present disclosure provides a mold apparatus capable of molding a molded product with high precision. [Means for solving the problem]

[0009] According to one aspect of the present disclosure, a mold apparatus includes a fixed mold and a movable mold that advances and retreats relatively to the fixed mold, and has a cavity between the fixed mold and the movable mold into which a molding material is filled, the mold apparatus including a first positioning mechanism that positions the fixed mold and the movable mold before a filling step in which the molding material is filled, a second positioning mechanism that is provided at a position different from the first positioning mechanism and that positions the fixed mold and the movable mold in a compression step in which the movable mold is advanced relative to the fixed mold after the filling step to compress the molding material, and a second positioning mechanism that is provided at a position different from the first positioning mechanism and that positions the fixed mold and the movable mold in a compression step in which the movable mold is advanced relative to the fixed mold after the filling step, and a second positioning mechanism that is provided at a position different from the first positioning mechanism and that positions the fixed mold and the movable mold in a compression step in which the molding material is compressed by advancing the movable mold relative to the fixed mold after the filling step, and and a movable body provided in the cavity, wherein the cavity has a flow end where the molding material injected from a gate reaches at the parting surface between the fixed mold and the movable mold, the movable body is movable relative to one of the molds or is fixed to one of the molds to allow a part of the one of the molds to move relatively, the movable body has a wall surface that constitutes a part of the cavity, and moves relative to the movable mold in a direction parallel to the flow direction of the molding material toward the flow end when the movable mold or a part of the one of the molds approaches and moves away from the fixed mold. Effect of the Invention

[0010] According to one aspect, the mold device can mold a molded product with high precision. [Brief description of the drawings]

[0011] [Figure 1] FIG. 2 is a cross-sectional view showing a die assembly according to the embodiment. [Diagram 2] Fig. 2(A) is a perspective view of a lid, which is a molded product formed by the mold device. Fig. 2(B) is a cross-sectional view taken along line IIB-IIB in Fig. 2(A). Fig. 2(C) is a partial cross-sectional view of a container, which is another example of a molded product formed by the mold device. [Diagram 3] 4 is an enlarged cross-sectional view showing a ring member of the blocking mechanism. FIG. [Figure 4] 2 is a flowchart showing a compression molding method according to an embodiment. [Diagram 5] Fig. 5(A) is a cross-sectional view showing a waiting state of the mold device, and Fig. 5(B) is a cross-sectional view showing the operation of the movable mold in a mold closing step. [Figure 6] Fig. 6(A) is a cross-sectional view showing a state of a mold device in a filling step, Fig. 6(B) is a partial cross-sectional view showing an enlarged first positioning mechanism in the filling step, and Fig. 6(C) is a partial cross-sectional view showing an enlarged second positioning mechanism in the filling step. [Figure 7] Fig. 7(A) is a partial cross-sectional view showing an enlarged portion of the filling space in the filling step, and Fig. 7(B) is a partial cross-sectional view showing an enlarged portion of the cavity in the compression step. [Figure 8] Fig. 8(A) is a cross-sectional view showing a state of the die device in the compression process, Fig. 8(B) is a partial cross-sectional view showing an enlarged view of the first positioning mechanism in the compression process, and Fig. 8(C) is a partial cross-sectional view showing an enlarged view of the second positioning mechanism in the compression process. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and duplicated descriptions may be omitted.

[0013] Fig. 1 is a cross-sectional view showing a mold apparatus 10 according to an embodiment. As shown in Fig. 1, the mold apparatus 10 according to the embodiment includes a fixed mold 20 and a movable mold 40 for molding a molded product. The mold apparatus 10 is installed in an injection molding machine 1, and molds a molded product by filling a molding material into a cavity 11 while the fixed mold 20 and the movable mold 40 are in a mold closed state. In the following explanation, directions will be explained based on the X-axis direction, the Y-axis direction, and the Z-axis direction in Fig. 1 as necessary. The X-axis direction, the Y-axis direction, and the Z-axis direction are perpendicular to each other.

[0014] The movable mold 40 of the mold device 10 moves relative to the fixed mold 20 under the control of a control device 9 provided in the injection molding machine 1. The control device 9 operates the drive source and transmission mechanism of the clamping device 2 of the injection molding machine 1 to move the movable mold 40 forward and backward. The forward and backward direction of the movable mold 40 is the Z-axis direction in FIG. 1. More specifically, the control device 9 advances the movable mold 40 in the negative Z-axis direction (direction approaching the fixed mold 20) to form a mold closed state (mold closing, mold clamping) between the movable mold 40 and the fixed mold 20. The control device 9 also retreats the movable mold 40 in the positive Z-axis direction (direction moving away from the fixed mold 20) to perform mold opening between the movable mold 40 and the fixed mold 20.

[0015] In the compression molding method, the injection molding machine 1 according to the embodiment performs a filling step of filling the molding material and a compression step of compressing the filled molding material in that order. That is, the injection molding machine 1 temporarily places the movable mold 40 at a filling position before the mold clamping position, and performs the filling step of filling the molding material with the injection device 3 in an expanded state of the cavity 11. After the filling step (or during the filling step), the injection molding machine 1 advances the movable mold 40 to perform a compression step of compressing the molding material in the cavity 11, thereby molding the final molded product.

[0016] FIG. 2(A) is a perspective view of a lid 100, which is a molded product molded by the mold device 10. FIG. 2(B) is a cross-sectional view taken along line IIB-IIB in FIG. 2(A). FIG. 2(C) is a partial cross-sectional view of a container 200, which is another example of a molded product molded by the mold device 10. An example of a molded product molded by the compression molding method is a lid 100 for a food cup container (a container for jelly, ice cream, etc.), which is a resin molded product shown in FIG. 2(A). This type of lid 100 has a thin wall and many flat parts. Specifically, the lid 100 has a flat part 101 formed in a disk shape and a cylindrical side part 102 that is bent and protrudes short from the outer edge of the flat part 101.

[0017] As shown in FIG. 2(B), the lid 100 has a space 100s inside the flat portion 101 and the side portion 102. Furthermore, the side portion 102 is slightly inclined with respect to a direction perpendicular to the flat portion 101 and is continuous with the outer edge of the flat portion 101. The molded product is not limited to the lid 100, and may be a container. The shape of the molded product is not limited to a disk shape or a cylinder shape, and may be various shapes, for example, a polygonal shape having corners.

[0018] Returning to FIG. 1, the fixed mold 20 of the mold device 10 is formed in a convex shape in a side cross-sectional view, and is capable of entering the concave movable mold 40. The fixed mold 20 according to the embodiment has a fixed-side base 21 fixed to a fixed platen (not shown) of the mold clamping device 2, and a fixed-side receiving portion 22 provided around a protruding portion of the fixed-side base 21 and in contact with the movable mold 40. The fixed-side base 21 and the fixed-side receiving portion 22 are configured as separate members. Note that the fixed platen and the fixed-side base 21 may not be directly fixed to each other, but may be fixed via a bracket (not shown) for connecting them together or a fixture for fixing them to each other.

[0019] The fixed-side base 21 includes a base end block portion 211 located in the negative direction of the Z axis, and a protruding block portion 212 protruding from the center of the base end block portion 211. The base end block portion 211 and the protruding block portion 212 are integrally molded with each other. The fixed-side base 21 also has a runner 21r extending in the Z axis direction inside the base end block portion 211 and the protruding block portion 212, and a gate 21g communicating with the runner 21r near a protruding end face 212a (the end face on the positive direction of the Z axis) of the protruding block portion 212.

[0020] A part (tip) of the protruding portion of the protruding block part 212 enters the movable mold 40 as the movable mold 40 moves. The protruding end face 212a of the protruding block part 212 is formed flat to form the flat part 101 of the lid 100 described above, and constitutes a part of the cavity 11. The protruding side face 212b connected to the outer edge of the protruding end face 212a of the protruding block part 212 constitutes a part of the cavity 11 to form the side part 102 of the lid 100 described above. However, the protruding end face 212a and the protruding side face 212b may have an appropriate shape depending on the molded product to be molded. The gate 21g is provided at the center of the protruding end face 212a, and discharges the molding material (e.g., resin material) flowing through the runner 21r into the cavity 11.

[0021] The fixed side receiving part 22 is fixed to one surface of the base end block part 211 and to the periphery of the protruding block part 212, and presents an annular body that goes around the base end block part 211. This fixed side receiving part 22 is a part that receives the mold clamping force of the movable mold 40 (including a ring member 51 described below). The fixed side receiving part 22 has a sufficient thickness, and its end surface in the positive direction of the Z axis forms a first fixed side divided surface 221 that comes into contact with the movable mold 40.

[0022] At a position where the base end block portion 211 and the fixed side receiving portion 22 overlap in the Z-axis direction, one of the first positioning mechanisms 13 for positioning the fixed mold 20 and the movable mold 40 before and during the filling process is formed. The first positioning mechanism 13 has a plurality of through holes 23 (first recesses) penetrating the base end block portion 211 and the fixed side receiving portion 22 in the thickness direction. The number of each through hole 23 is not particularly limited, but it is preferable to provide, for example, three or more, in order to suppress misalignment between the fixed mold 20 and the movable mold 40 in the X-axis and Y-axis directions. In FIG. 1, two through holes 23 are illustrated for convenience of explanation.

[0023] A bushing 24 that is smaller than the inside dimension (inner diameter) of the other parts of the through hole 23 is provided on the inner peripheral surface of the base end block portion 211 that constitutes each through hole 23. The bushing 24 is press-fitted into the base end block portion 211 from the Z-axis negative direction of each through hole 23. The bushing 24 defines the narrowest inner diameter of the through hole 23. The inner diameter of this bushing 24 is set slightly larger than the outer diameter of the positioning pin 43 of the movable mold 40, and suppresses misalignment between the fixed mold 20 and the movable mold 40 while allowing the positioning pin 43 to enter.

[0024] The fixed-side receiving portion 22 has a second fixed-side divided surface 222 recessed toward the negative Z-axis direction relative to the first fixed-side divided surface 221 at a position outside (a position farther from the center) than each through-hole 23. A fixed-side inclined surface 223 is formed between the first fixed-side divided surface 221 and the second fixed-side divided surface 222.

[0025] The fixed-side inclined surface 223 constitutes one of the second positioning mechanisms 14 that position the fixed mold 20 and the movable mold 40. The fixed-side inclined surface 223 is disposed at an outer adjacent position of each through hole 23, and is formed in an annular shape over the entire circumferential direction of the fixed-side receiving part 22. The fixed-side inclined surface 223 is inclined so as to narrow inwardly toward the positive direction of the Z axis. For example, the inclination angle θf of the fixed-side inclined surface 223 is inclined in a range of about 45° to 85° with respect to the second fixed-side divided surface 222.

[0026] On the other hand, the movable mold 40 is fixed to a movable platen (not shown) of the mold clamping unit 2. The movable platen and the movable mold 40 may also be fixed via a bracket (not shown) for connecting them or a fastener for fixing them to each other, rather than being fixed directly to each other. The surface of the movable mold 40 on the negative Z-axis direction side has a central portion 41 that is recessed with respect to side portions 42. The central portion 41 is formed flat and faces the protruding end surface 212a of the fixed mold 20.

[0027] The side portion 42 has divided surfaces (a first movable side divided surface 421 and a second movable side divided surface 422) that are positioned differently in the Z-axis direction. The second movable side divided surface 422 protrudes in the negative Z-axis direction relative to the first movable side divided surface 421. The first movable side divided surface 421 faces the first fixed side divided surface 221 and comes into surface contact with the first fixed side divided surface 221 in the clamped state. The second movable side divided surface 422 faces the second fixed side divided surface 222 and comes into surface contact with the second fixed side divided surface 222 in the clamped state.

[0028] Further, inside the movable mold 40 corresponding to the first movable side divided surface 421, a plurality of positioning pins 43 are provided so as to protrude from the first movable side divided surface 421. Each positioning pin 43 is provided at a position corresponding to each through hole 23, and constitutes the other of the first positioning mechanism 13. In other words, each positioning pin 43 is provided in the same number as the through holes 23 along the circumferential direction of the first movable side divided surface 421 which goes around in an annular shape.

[0029] The movable mold 40 has a plurality of retaining holes 45 into which the positioning pins 43 are inserted and retained, and a plurality of screw insertion holes 46 that communicate with the retaining holes 45 and penetrate toward the positive direction of the Z axis. A fixing bolt 47 for fixing the positioning pins 43 is inserted into each screw insertion hole 46.

[0030] Each positioning pin 43 has a female screw portion 43a at an end in the Z-axis positive direction, and this female screw portion 43a is screwed onto a fixing bolt 47 inside a retaining hole 45. As a result, each positioning pin 43 is firmly fixed to the movable mold 40 in a state in which it protrudes from the first movable side divided surface 421 in the Z-axis negative direction.

[0031] Each positioning pin 43 is formed in a cylindrical shape having a constant outer diameter along the Z-axis direction (the direction in which the movable mold 40 advances and retreats), and the protruding end on the negative side of the Z-axis is formed with rounded corners. Each positioning pin 43 has an outer dimension (outer diameter) slightly smaller than the inner diameter of the bush 24 of the fixed mold 20, and is inserted into each through hole 23 when the movable mold 40 advances relative to the fixed mold 20. The first positioning mechanism 13 can stably position the fixed mold 20 and the movable mold 40 by inserting each positioning pin 43 of the movable mold 40 into each through hole 23 of the fixed mold 20 when advancing before the filling step.

[0032] Furthermore, the movable mold 40 has a movable side inclined surface 423 constituting the other of the second positioning mechanism 14 on the inner peripheral surface between the first movable side divided surface 421 and the second movable side divided surface 422. The movable side inclined surface 423 is disposed at a position adjacent to the outer side of each positioning pin 43, and is formed in an annular shape over the entire circumferential direction of the side portion 42. This movable side inclined surface 423 is inclined so as to widen outwardly of the movable mold 40 in the negative direction of the Z axis.

[0033] For example, the inclination angle θm of the movable-side inclined surface 423 is formed to match the inclination angle θf (for example, in the range of about 45° to 85°) of the fixed-side inclined surface 223, thereby enabling surface contact with the fixed-side inclined surface 223. Note that the inclination angle θf of the fixed-side inclined surface 223 and the inclination angle θm of the movable-side inclined surface 423 may be different from each other, and for example, the inclination angle θm may be set to be larger than the inclination angle θf.

[0034] The movable mold 40 is provided with a blocking mechanism 50 for blocking the molding material filled in the cavity 11 at a location constituting the outermost surface (the outermost side surface of the molded product) in the cavity 11. The "outermost side surface" of the molded product refers to a portion that is located at a position farthest from the center of the molded product injection molded by the gate 21g and that constitutes a surface of a certain length at a position different from the end (end surface) formed by the thickness of the molded product. Therefore, in the case of the lid 100 shown in FIG. 2(B), the outermost side surface refers to the outer peripheral surface 102a of the side portion 102, and does not include the surface 102b of the protruding end of the side portion 102. The surface 102b of the protruding end of the side portion 102 is a portion that is molded by the flow end of the cavity 11 where the molding material finally reaches in the filling process or the compression process.

[0035] 2(C), the outermost side surface refers to the outer peripheral surface 201a of the folded portion of the flange 201, and does not include the surface 201b of the protruding end of the flange 201. The surface 201b of the protruding end of the flange 201 is the portion that is molded by the flow end of the cavity where the molding material finally reaches in the filling process or compression process.

[0036] Specifically, the blocking mechanism 50 has a ring-shaped accommodation space 48 surrounding the central portion 41, between the central portion 41 and the side portion 42. Furthermore, the blocking mechanism 50 includes, in this accommodation space 48, an annular ring member 51 (movable body) that moves relatively to the movable mold 40, and a plurality of elastic members 53 that hold this ring member 51 so that it can move relatively.

[0037] Each elastic member 53 applies a biasing force that pushes the ring member 51 in a direction away from the bottom of the accommodation space 48 (toward the negative Z-axis direction). Each elastic member 53 is arranged at intervals along the circumferential direction of the accommodation space 48, with one end connected to the bottom of the accommodation space 48 and the other end on the opposite side in contact with the ring member 51. Although a coil spring is applied to each elastic member 53 in Fig. 1, this is not particularly limited, and a thermosetting elastomer such as rubber or urethane, or a cylinder mechanism, a damper mechanism, or the like may be used.

[0038] Meanwhile, the ring member 51 is connected to each elastic member 53 in the accommodation space 48, so that it can move parallel to the advancing and retreating direction of the movable mold 40. In other words, when the movable mold 40 approaches and moves away from the fixed mold 20, the ring member 51 moves in a direction parallel to the flow direction of the molding material toward the flow end. The ring member 51 is configured to cover a part of the cavity 11, and is disposed near the flow end of the molding material flowing through the cavity 11. The configuration of the ring member 51 will be described in more detail below with reference to FIG. 3. FIG. 3 is an enlarged cross-sectional view showing the ring member 51 of the blocking mechanism 50.

[0039] The ring member 51 has a ring member side divided surface 511 facing the first fixed side divided surface 221 of the fixed mold 20. The ring member side divided surface 511 is formed parallel to and flat with the first fixed side divided surface 221 and is capable of coming into surface contact with the first fixed side divided surface 221.

[0040] The accommodation space 48 of the movable mold 40 has a step receiving surface 48a that receives a base end surface (the surface opposite to the ring member side divided surface 511) of the ring member 51 in a state in which the ring member 51 is accommodated. The ring member 51 is set to a size such that the ring member side divided surface 511 is aligned flush with the first movable side divided surface 421 in a state in which the base end surface contacts the step receiving surface 48a and retreat in the positive direction of the Z axis is restricted.

[0041] The inner peripheral surface of the ring member 51 has an inner sliding surface 512 that slidably contacts the first side surface 481 of the movable mold 40 that constitutes the accommodation space 48. Similarly, the outer peripheral surface of the ring member 51 has an outer sliding surface 513 that slidably contacts the second side surface 482 of the movable mold 40 that constitutes the accommodation space 48. The gap between the first side surface 481 and the inner sliding surface 512 is set to be sufficiently smaller (than the gap between the second side surface 482 and the outer sliding surface 513). Thereby, in the assembly process or in relation to tolerances, it may be required to have a dimensional relationship that generates a gap, and even in such a case, it is possible to prevent the molding material from entering the gap between the first side surface 481 and the inner sliding surface 512 in the filling process or compression process.

[0042] The inner sliding surface 512 is located inside a wall surface 516 of the ring member 51, which will be described later. In the relative movement between the movable mold 40 and the ring member 51, the inner sliding surface 512 of the ring member 51 is guided by the first side surface 481. In particular, the first side surface 481 and the inner sliding surface 512 extend parallel to the movement direction (Z-axis direction) of the movable mold 40. This allows the ring member 51 to smoothly advance and retreat in the Z-axis direction within the accommodation space 48, independent of the movement of the movable mold 40.

[0043] Furthermore, the inner peripheral surface of the ring member 51 has a cavity forming surface portion 514 that constitutes a part of the cavity 11, located adjacent to the inner sliding contact surface 512 on the Z-axis negative side. The cavity forming surface portion 514 forms the corners and the outermost side surface of the lid 100 (molded product). Specifically, the cavity forming surface portion 514 includes a step surface 515 that is perpendicular to the inner sliding contact surface 512, and a wall surface 516 that extends from the step surface 515 toward the ring member side divided surface 511.

[0044] The ring member 51 has a step surface 515 between the inner sliding surface 512 and the wall surface 516, since the inner sliding surface 512 is located closer to the center of the movable mold 40 than the wall surface 516. This allows the ring member 51 to use the step surface 515 as a portion that constitutes part of the cavity 11.

[0045] The step surface 515 is formed in an annular shape in a plan view, extends parallel to and a short distance from the protruding end surface 212a, and faces the outer periphery of the protruding end surface 212a of the fixed mold 20. This step surface 515 is disposed at a position in the Z-axis direction that is flush with the central portion 41 of the movable mold 40 when the ring member side divided surface 511 is in contact with the first fixed side divided surface 221 during the compression process. This allows the ring member 51 to form the outer edge of the flat portion 101 of the lid 100 with high precision.

[0046] The wall surface 516 is disposed at a position outside (away from the center of the central portion 41) the inner sliding contact surface 512. The wall surface 516 cooperates with the protruding side surface 212b of the fixed mold 20 to form the side portion 102 of the lid 100 during injection molding by the injection molding machine 1. In other words, the wall surface 516 is a portion that constitutes a part of the cavity 11 in the ring member 51. The wall surface 516 goes around the inner circumferential surface of the ring member 51 in an annular shape, thereby enabling the outer circumferential surface (the outermost side surface) of the lid 100 to be stably formed.

[0047] Moreover, the protruding side surface 212b and the wall surface 516 according to the embodiment are inclined with respect to the movement direction (Z-axis direction) of the ring member 51 in order to form a tapered side portion 102. Specifically, the protruding side surface 212b and the wall surface 516 are inclined at the same angle so as to spread outward in the negative Z-axis direction, and extend in parallel. Since the wall surface 516 is inclined with respect to the movement direction, the movable mold 40 (including the ring member 51) can be smoothly retracted with respect to the fixed mold 20.

[0048] The mold device 10 can arbitrarily design the shapes of the protruding side surface 212b and the wall surface 516 according to the shape of the lid 100 to be molded. For example, the protruding side surface 212b and the wall surface 516 may form a space whose thickness changes toward the protruding end of the side portion 102 of the lid 100.

[0049] The mold device 10 according to the present embodiment is basically configured as described above, and its operation and effect will be described below with reference to Figs. 4 to 8(C). Fig. 4 is a flow chart showing a compression molding method according to the embodiment. Fig. 5(A) is a cross-sectional view showing the waiting state of the mold device 10. Fig. 5(B) is a cross-sectional view showing the operation of the movable mold 40 in the mold closing process. Fig. 6(A) is a cross-sectional view showing the state of the mold device 10 in the filling process. Fig. 6(B) is a partial cross-sectional view showing an enlarged view of the first positioning mechanism 13 in the filling process. Fig. 6(C) is a partial cross-sectional view showing an enlarged view of the second positioning mechanism 14 in the filling process. Fig. 7(A) is a partial cross-sectional view showing an enlarged view of a part of the filling space 12 in the filling process. Fig. 7(B) is a partial cross-sectional view showing an enlarged view of a part of the cavity 11 in the compression process. Fig. 8(A) is a cross-sectional view showing the state of the mold device 10 in the compression process. Fig. 8(B) is a partial cross-sectional view showing an enlarged view of the first positioning mechanism 13 in the compression process. FIG. 8C is an enlarged partial cross-sectional view of the second positioning mechanism 14 during the compression step.

[0050] 4, in the compression molding method of the mold device 10, a mold closing step (step S1), a filling step (step S2), a compression step (step S3), and a mold opening step (step S4) are performed in this order under the control of the control device 9 of the injection molding machine 1. The compression step is not limited to being started after the filling step, and may be started during the filling step.

[0051] 5(A), before carrying out the compression molding method, the movable mold 40 is disposed in a standby position away from the fixed mold 20 (each positioning pin 43 is away from each through hole 23). After starting the mold closing process, the control device 9 of the injection molding machine 1 operates the mold clamping device 2 to move the movable mold 40 forward in the negative direction of the Z axis. In this mold closing process, the injection molding machine 1 detects the position and moving speed of the movable mold 40 by an encoder or the like, and moves the movable mold 40 based on the detection results.

[0052] As the movable mold 40 advances in the mold closing process, the positioning pins 43 are inserted into the through holes 23, thereby positioning the fixed mold 20 and the movable mold 40 in the X-axis and Y-axis directions. As a result, in the mold closing process, the movable mold 40 approaches the fixed mold 20 while being guided without being significantly misaligned in the X-axis and Y-axis directions relative to the fixed mold 20.

[0053] 6(B), the outer diameter of the positioning pin 43 is slightly smaller than the inner diameter of the bush 24. Therefore, when each positioning pin 43 is inserted into each through hole 23, a first gap 13c is formed between the inner peripheral surface of the bush 24 constituting each through hole 23 and the outer peripheral surface of each positioning pin 43. It is preferable that the first gap 13c is designed in advance to an appropriate distance D1 (and cross-sectional area) that allows each positioning pin 43 to move in the forward and backward directions relative to the fixed mold 20 while being able to position the fixed mold 20 and the movable mold 40 to some extent.

[0054] 6(C), a pre-compression second gap 14c1 is formed between the fixed-side inclined surface 223 of the fixed mold 20 and the movable-side inclined surface 423 of the movable mold 40, which constitute the second positioning mechanism 14. In the pre-compression position, the distance D2a of the pre-compression second gap 14c1 is larger than the distance D1 of the first gap 13c. This allows the mold device 10 to position the fixed mold 20 and the movable mold 40 by the first positioning mechanism 13 without using the second positioning mechanism 14 before the filling step.

[0055] Returning to Fig. 5(B), as the movable mold 40 continues to advance, the blocking mechanism 50 (ring member 51) of the movable mold 40 first comes into contact with the fixed mold 20. At this time, the ring member side divided surface 511 comes into contact with the first fixed side divided surface 221 of the fixed mold 20, and the movement of the ring member 51, which is driven by the advance of the movable mold 40, stops. Thereafter, as the movable mold 40 advances, the ring member 51 is displaced toward the back of the accommodation space 48 while contracting the elastic member 53.

[0056] Furthermore, the control device 9 continues the forward movement of the movable mold 40, and stops the forward movement when the movable mold 40 is placed at the filling position as shown in Fig. 6(A). At the filling position, the fixed mold 20 and the movable mold 40 form a filling space 12 larger than the cavity 11 for molding the molded product (see also Fig. 7(A)). Note that the injection molding machine 1 may move the movable mold 40 closer to or in contact with the fixed mold 20 than the filling position, and then perform an operation of retracting the movable mold 40 to place the movable mold 40 at the filling position.

[0057] 7(A), when the movable mold 40 is located at the filling position, the flow end of the filling space 12 is surrounded and blocked by the protruding side surface 212b and the first fixed-side divided surface 221 of the fixed mold 20, and the wall surface 516 of the ring member 51. This makes it possible to block leakage of molding material from the flow end of the filling space 12 during the filling process, thereby preventing burrs from occurring on the molded product.

[0058] In the filling step, the control device 9 moves the injection device 3 (see FIG. 1) to the fixed mold 20, and the injection device 3 fills the filling space 12 with molding material through the runner 21r and the gate 21g. At this time, the filling space 12, which has a volume larger than the cavity 11, allows the molding material to flow smoothly therein. The molding material filled in the filling space 12 is heated in the injection device 3, so that it maintains a liquid or semi-solid state during the filling step.

[0059] The molding material spreads in the X-axis and Y-axis directions and moves radially outward in the filling space 12 corresponding to the flat portion 101 of the lid 100 to be molded. In this filling process, the stepped surface 515 of the ring member 51 is positioned offset in the positive direction of the Z-axis from the adjacent central portion 41 (the surface that constitutes the cavity 11 of the movable mold 40). In other words, the central portion 41 is set back from the stepped surface 515, which allows the molding material to fill smoothly.

[0060] Then, the molding material that has reached the outer edge of the flat portion 101 moves in the negative direction of the Z axis in the filling space 12 that corresponds to the side portion 102 of the lid 100 to be molded. That is, the flow direction of the molding material in the side portion 102 coincides with the forward movement direction of the movable mold 40 and the ring member 51. In other words, the forward and backward direction of the ring member 51 is parallel to the movement direction of the molding material at the flow end of the filling space 12 (cavity 11).

[0061] As described above, the side portion 102 is inclined (see FIG. 2(B)), and the flow direction of the molding material passing between the protruding side surface 212b and the wall surface 516 is also inclined with respect to the Z-axis direction. However, the inclination of the protruding side surface 212b and the wall surface 516 is slight, and the flow direction of the molding material can be considered to move substantially in the negative direction of the Z-axis. In other words, in this description, the movement direction of the ring member 51 being parallel to the flow direction of the flow end of the molding material is a concept that includes a form in which the protruding side surface 212b and the wall surface 516 are slightly inclined (for example, inclined at about 0° to 5° with respect to the Z-axis direction).

[0062] 7(B) and 8(A), during or after the filling step, the control device 9 performs a compression step in which the movable mold 40 is further advanced in the negative direction of the Z axis to compress the filled molding material (see also FIG. 4). At this time, the movable mold 40 moves to the clamping position, and a cavity 11 for molding a molded product is formed between the fixed mold 20 and the movable mold 40. As the molding material filled in the filling space 12 moves, more and more, toward the flow end of the cavity 11 corresponding to the side portion 102 of the lid 100.

[0063] When the movable die 40 advances in the compression step, the ring member 51 is pressed more strongly in the negative direction of the Z axis by the elastic member 53. This brings the ring member-side divided surface 511 of the ring member 51 and the first fixed-side divided surface 221 of the fixed die 20 into firm contact with each other, making it possible to prevent lateral burrs on the molded product.

[0064] Furthermore, the filling step causes the central portion 41 of the movable mold 40 and the step surface 515 of the ring member 51 to be positioned flush with each other. At this time, the inner sliding surface 512 of the ring member 51 and the first side surface 481 of the movable mold 40 extend relative to each other in the Z-axis direction, so that the ring member 51 can slide smoothly while stably shielding the molding material of the cavity 11. In a clamping completed state in which the movable mold 40 is positioned at the clamping position, the mold device 10 can mold the lid 100 in which the flat portion 101 and the side portion 102 are integrated.

[0065] In molding the lid 100, the wall surface 516 of the ring member 51 forms the outermost side surface (outer peripheral surface 102a) of the lid 100 molded by the cavity 11. The wall surface 516 is approximately perpendicular to the first fixed side divided surface 221 of the fixed mold 20, and the ring member 51 is pressed against the first fixed side divided surface 221 by the elastic member 53, thereby preventing burrs from being generated on the protruding end of the side portion 102. As a result, the mold device 10 can precisely mold a molded product (lid 100) having a clean outermost side surface (flow end of the molding material).

[0066] In the compression step, the mold device 10 positions the fixed mold 20 and the movable mold 40 by the second positioning mechanism 14. Specifically, as the movable mold 40 advances relative to the fixed mold 20, the fixed-side inclined surface 223 of the fixed mold 20 and the movable-side inclined surface 423 of the movable mold 40 come into contact with each other, and the movable mold 40 advances while the fixed-side inclined surface 223 and the movable-side inclined surface 423 are in sliding contact with each other. This allows the fixed mold 20 and the movable mold 40 to be positioned with high precision in the X-axis and Y-axis directions.

[0067] At the stage where the movable mold 40 moves to the mold clamping position, as shown in Fig. 8(A) to Fig. 8(C), the fixed side inclined surface 223 and the movable side inclined surface 423 are in surface contact with each other in a tapered manner. That is, the interval D2b (and the cross-sectional area) of the second gap 14c2 after compression between the fixed side inclined surface 223 and the movable side inclined surface 423 of the second positioning mechanism 14 becomes smaller than the second gap 14c1 before compression during the filling step (specifically, becomes zero). Since the interval D2b of the second gap 14c2 after compression is smaller than the interval D1 of the first gap 13c of the first positioning mechanism 13, the mold device 10 can perform the positioning of the fixed mold 20 and the movable mold 40 in the compression step with high accuracy.

[0068] Furthermore, since the fixed side inclined surface 223 of the fixed mold 20 and the movable side inclined surface 423 of the movable mold 40 each rotate endlessly, the second positioning mechanism 14 positions the molds relative to each other over the entire circumference of the cavity 11. As a result, the second positioning mechanism 14 advances the movable mold 40 while dispersing the stress applied to positioning in the X-axis and Y-axis directions (directions perpendicular to the advancing and retreating directions) during the compression process. As a result, the core of the fixed mold 20 and the core of the movable mold 40 smoothly align with each other.

[0069] On the other hand, the first gap 13c (distance D1) of the filling process is maintained even in the compression process between the inner circumferential surface of the bush 24 of each through hole 23 and the outer circumferential surface of each positioning pin 43 constituting the first positioning mechanism 13. In other words, the influence of the first positioning mechanism 13 in terms of positioning during the compression process is smaller than the influence of the second positioning mechanism 14. The relationship between the distance D1 of the first gap 13c, the distance D2a of the pre-compression second gap 14c1, and the distance D2b of the post-compression second gap 14c2 during the operation of the above-described mold device 10 is expressed by the following formula (1).

[0070] D2a>D1>D2b …(1)

[0071] In this way, the mold apparatus 10 positions the fixed mold 20 and the movable mold 40 by the first positioning mechanism 13 before the filling step, and positions the fixed mold 20 and the movable mold 40 by the second positioning mechanism 14 in the compression step after the filling step. This allows the mold apparatus 10 to position the fixed mold 20 and the movable mold 40 with high precision while suppressing the load (e.g., galling of the positioning mechanism) that occurs when positioning between the fixed mold 20 and the movable mold 40, eliminating misalignment between the fixed mold 20 and the movable mold 40. In other words, the mold apparatus 10 prevents uneven thickness of the molded product molded in the compression step, avoids various defects associated with uneven thickness, and can satisfactorily mold thin-walled molded products.

[0072] Then, in the mold opening step after the compression step, the control device 9 operates the mold clamping device 2 to move the movable mold 40 from the clamping position in the positive Z-axis direction, thereby separating the movable mold 40 from the fixed mold 20. Thereafter, the injection molding machine 1 ejects the lid 100 from the movable mold 40 using an ejector device (not shown), thereby completing this compression molding method. Note that the compression molding method may be configured to perform a depressurization step in which the movable mold 40 is moved slightly backward from the clamping position to reduce the pressure in the cavity 11 before the mold opening step, and then perform the mold opening step.

[0073] As described above, the mold assembly 10 according to the embodiment has the wall surface 516 that constitutes a part of the cavity 11, and has the ring member 51 that moves in a direction parallel to the flow direction of the molding material toward the flow end, so that the outermost surface of the molded product can be molded well during the compression process. As a result, the mold assembly 10 can mold the molded product with high precision. In addition, since the wall surface 516 is inclined with respect to the movement direction of the ring member 51, the dimensional tolerance of the cavity 11 is guaranteed, and the ring member 51 can be smoothly separated from the fixed mold 20.

[0074] Furthermore, since the ring member 51 is formed in an annular shape and has the inner sliding surface 512 on its inner peripheral surface, the relative position of the ring member 51 with respect to the movable mold 40 can be stabilized, and the molding accuracy of the molded product can be improved. Furthermore, since the inner sliding surface 512 of the ring member 51 is located closer to the center of the movable mold 40 than the wall surface 516, the outermost surface of the molded product can be formed only by the wall surface 516, and therefore the molding accuracy can be further improved. Since the step surface 515 is aligned flush with the central portion 41 in the compression process, the mold device 10 can smoothly guide the molding material to the flow end in the compression process while facilitating the flow of the molding material in the filling process.

[0075] The mold device 10 is not limited to the above embodiment, and may take various modified forms. For example, the mold in which the moving body (ring member 51) of the blocking mechanism 50 is provided is not limited to the movable mold 40, and may be the fixed mold 20. In addition, the moving body is not limited to annular in plan view, and can be freely designed according to the shape of the molded product, and may be rectangular, arcuate, linear, etc.

[0076] Moreover, the above-mentioned mold device 10 is configured to include the second positioning mechanism 14 (the fixed-side inclined surface 223, the movable-side inclined surface 423) on the outer side of the first positioning mechanism 13 (each through hole 23, the positioning pin 43). However, the mold device 10 is not limited to this configuration, and may include the first positioning mechanism 13 on the outer side of the second positioning mechanism 14.

[0077] As a modified example, the mold device 10 may be configured such that the ring member 51 in FIG. 1, which is the moving body, is integrally molded with the movable mold 40, while the tip end portion of the central portion 41 in FIG. 1 (a part of the movable mold 40) is relatively movable. Here, the term "moving body" is not limited to one that moves by itself, but also includes one in which a part other than the moving body of one mold moves. In other words, the term "moving body" is used to mean one that moves relatively to a part other than the moving body of one mold. That is, in the compression process, the tip end portion of the central portion 41 is moved relatively to the movable mold 40 (ring member 51) to approach the protruding end surface 212a of the fixed mold 20.

[0078] In the above embodiment and modified examples, a mechanism may be provided that allows the movable body (e.g., ring member 51) and the member that moves relatively to the movable body to move relative to each other and to be positioned relatively without providing a sliding surface between them. When no sliding surface is provided, the movable body and the member that moves relatively to the movable body are configured to contact and slide over substantially the entire surface at the boundary of cavity 11, and configured so that resin does not leak from this boundary. Even in this case, the molding material pushed to the tip of central portion 41 flows to the flow end of cavity 11, and the outermost surface of the molded product can be formed with high accuracy by ring member 51 fixed to movable mold 40.

[0079] The mold apparatus 10 according to the embodiment disclosed herein is illustrative in all respects and is not restrictive. The embodiment can be modified and improved in various forms without departing from the scope and spirit of the appended claims. The matters described in the above embodiments can be configured in other ways as long as they are not inconsistent, and can be combined as long as they are not inconsistent. [Explanation of symbols]

[0080] 10. Mold Equipment 11 Cavity 13 First positioning mechanism 14 Second positioning mechanism 20 Fixed mold 21g Gate 40 Movable mold 48 Containment Space 481 1st aspect 482 Second aspect 51 Ring member 512 Inner sliding surface 513 Outside sliding surface 515 Step surface 516 Wall

Claims

1. A mold apparatus comprising a fixed mold and a movable mold that moves forward and backward relative to the fixed mold, the mold apparatus having a cavity between the fixed mold and the movable mold into which a molding material is filled, a first positioning mechanism that positions the fixed mold and the movable mold before a filling step of filling the molding material; a second positioning mechanism that is provided at a position different from that of the first positioning mechanism and that positions the fixed mold and the movable mold in a compression step in which the movable mold is advanced relative to the fixed mold after the filling step to compress the molding material; and a movable body provided on one of the fixed mold and the movable mold, the cavity has a flow end at a parting surface between the fixed mold and the movable mold, where the molding material injected from the gate reaches, the movable body is movable relative to the one of the dies, or is fixed to the one of the dies to allow a part of the one of the dies to be moved relatively; the movable body has a wall surface constituting a part of the cavity, and moves relative to the movable mold in a direction parallel to the flow direction of the molding material toward the flow end when the movable mold or a part of one of the molds approaches and moves away from the fixed mold. Mold equipment.

2. The wall surface is inclined with respect to a moving direction of the relative movement of the movable body. The mold apparatus according to claim 1 .

3. The movable body is formed in an annular shape and has the wall surface on an inner circumferential surface. The mold apparatus according to claim 1 .

4. The movable body is movable relative to the one of the dies, the fixed die and the movable die, in which the movable body is provided, has an accommodation space for accommodating the movable body; A side surface of the accommodation space and a sliding surface of the movable body facing the side surface are provided parallel to a moving direction of the movable body. The mold apparatus according to any one of claims 1 to 3.

5. The sliding surface is located closer to the center of the mold, in which the movable body is provided, than the wall surface. The mold apparatus according to claim 4.

6. the movable body has a step surface that constitutes a part of the cavity between the sliding contact surface and the wall surface, The step surface is In the filling step, the cavity is located at a position offset from a surface that constitutes the adjacent cavity, In the compression process, the adjacent cavities are aligned flush with each other. The mold apparatus according to claim 4.

7. A mold apparatus comprising a fixed mold and a movable mold that moves forward and backward relative to the fixed mold, the mold apparatus having a cavity between the fixed mold and the movable mold into which a molding material is filled, a first positioning mechanism that positions the fixed mold and the movable mold before a filling step of filling the molding material; a second positioning mechanism that is provided at a position different from that of the first positioning mechanism and that positions the fixed mold and the movable mold in a compression step in which the movable mold is advanced relative to the fixed mold after the filling step to compress the molding material; and a movable body provided on one of the fixed mold and the movable mold, the movable body is movable relative to the one of the dies, or is fixed to the one of the dies to allow a part of the one of the dies to be moved relatively; the movable body has a wall surface that forms the outermost surface of a molded product to be molded by the cavity, and moves in a direction parallel to the advancing and retreating direction of the movable mold when the movable mold or a part of one of the molds approaches the fixed mold before the filling step. Mold equipment.

8. The wall surface is inclined with respect to the moving direction of the moving body. The mold apparatus according to claim 7.

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