Mold equipment and injection molding machines

Abstract

To provide a technique capable of accurately positioning a stationary mold and a movable mold in compression molding.SOLUTION: A mold device has a stationary mold and a movable mold that relatively advances to / retracts from the stationary mold. The mold device comprises a first positioning mechanism provided on the stationary mold and the movable mold to position the stationary mold and the movable mold before a filling step of filling a mold material. Alternately, the mold device comprises a second positioning mechanism provided at a position different from the first positioning mechanism to position the stationary mold and the movable mold in a compression step of advancing the movable mold with respect to the stationary mold after the filling step, to compress the mold material.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a mold apparatus and an injection molding machine. [Background technology]

[0002] In order to obtain a molded product of a desired thickness (e.g., a thin-walled molded product) in 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 sequence. For example, a mold assembly is configured such that a movable mold is positioned at a position retreated from a clamping position based on the operation of an injection molding machine, thereby expanding the cavity space, and the molding material is filled in this state. During or after filling, the mold assembly advances the movable mold to the clamping position, thereby compressing the molding material and forming a molded product.

[0003] This type of mold device has the problem that when producing thin-walled molded products, the molding material solidifies before it reaches the end of the cavity, making it difficult for the pressure of the molding material to reach the end, which can result in uneven thickness (uneven thickness) in the molded product.One of the causes of solidification of the molding material is misalignment of the space due to misalignment between the fixed mold and the movable mold.

[0004] Patent document 1 discloses a mold device 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] Japanese Patent Application Laid-Open No. 2004-174714 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 galling of the insert ring during positioning or low positioning accuracy.

[0007] Specifically, if a tapered portion is used in the positioning mechanism for the fixed mold and the movable mold, the distance between the molds will be further reduced in the compression process in order to ensure positioning accuracy in the filling process, which will result in galling. Furthermore, in order to ensure positioning accuracy in the compression process, the positioning mechanism's positioning accuracy will be reduced in the filling process before compression, which will result in uneven thickness and reduced dimensional accuracy of the molded product.

[0008] The present invention provides a technique that enables highly accurate positioning of a fixed mold and a movable mold in compression molding. [Means for solving the problem]

[0009] According to one aspect of the present invention, there is provided a mold device having a fixed mold and a movable mold that moves forward and backward relative to the fixed mold, the mold device comprising: a first positioning mechanism that is provided on the fixed mold and the movable mold and positions the fixed mold and the movable mold before a filling process in which a molding material is filled; and a second positioning mechanism that is provided at a position different from the first positioning mechanism and positions the fixed mold and the movable mold in a compression process in which the movable mold is advanced relative to the fixed mold after the filling process to compress the molding material. [Effects of the Invention]

[0010] A mold device and an injection molding machine according to one aspect can perform highly accurate positioning of a fixed mold and a movable mold during compression molding. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a cross-sectional view showing a schematic configuration of a part of a mold device and a part of an injection molding machine; [Figure 2] FIG. 2 is a perspective view showing a cup container for food, which is a molded product of the mold device. [Figure 3] 1 is a flowchart showing the steps of a compression molding method. [Figure 4] Figure 4(A) is a cross-sectional view showing a schematic diagram of the mold device before the filling process, Figure 4(B) is an enlarged cross-sectional view of the first positioning mechanism, and Figure 4(C) is an enlarged cross-sectional view of the second positioning mechanism. [Figure 5] Figure 5(A) is a cross-sectional view showing a schematic diagram of the mold device after the compression process, Figure 5(B) is an enlarged cross-sectional view of the first positioning mechanism, and Figure 5(C) is an enlarged cross-sectional view of the second positioning mechanism. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments 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 redundant explanations may be omitted.

[0013] As shown in Fig. 1, a mold apparatus 1 according to one embodiment is installed in an injection molding machine and includes a fixed mold 10 and a movable mold 30 for molding a molded product by filling molding material from the injection molding machine. Fig. 1 is a schematic diagram illustrating the configuration of a portion of the mold apparatus 1. In the following explanation, directions will be described based on the X-axis, Y-axis, and Z-axis directions in Fig. 1 as necessary. The X-axis, Y-axis, and Z-axis directions are perpendicular to each other.

[0014] The movable mold 30 of the mold device 1 is configured to move forward and backward relative to the fixed mold 10 under the operation of a mold clamping device provided in the injection molding machine. A control device 55 of the injection molding machine controls an operating unit 52 (drive source, transmission mechanism, etc.) of the mold clamping device to move the movable mold 30 forward in the positive direction of the Z axis, thereby performing mold closing and mold clamping between the movable mold 30 and the fixed mold 10. The control device 55 also controls the operating unit 52 to move the movable mold 30 backward in the negative direction of the Z axis, thereby performing mold opening from the fixed mold 10.

[0015] The mold assembly 1 and injection molding machine according to this embodiment perform the compression molding method as described above. That is, the injection molding machine performs a filling step in which the injection device 53 fills the molding material in the cavity space 2 with the movable mold 30 positioned ahead of the mold clamping position to enlarge the cavity space 2. During or after filling, the injection molding machine performs a compression step in which the movable mold 30 moves forward to compress the molding material in the cavity space 2, thereby forming a molded product.

[0016] Molded products formed by compression molding are not particularly limited, but examples include a food cup container 100 (a container for jelly, ice cream, etc.) or a lid for covering a container, as shown in FIG. 2. In particular, for molded products with thin walls and many flat surfaces, compression molding allows for stable molding of high-precision products. The food cup container 100 in FIG. 2 has a container bottom 101, a cylindrical container side 102 connected to the container bottom, and a container flange 103 that protrudes slightly outward from the end of the container side 102. While FIG. 2 illustrates a substantially cylindrical food cup container 100, it goes without saying that the molded product formed by the mold device 1 may also be a rectangular container with corners.

[0017] When clamped, the fixed mold 10 and the movable mold 30 of the mold device 1 form a cavity space 2 (see FIG. 5(A)) on their opposing surfaces. The cavity space 2 according to this embodiment has the shape of a cup container 100 for food.

[0018] The fixed mold 10 has a fixed-side base 11 that is formed in a concave shape in a side cross-sectional view and is fixed to a fixed platen (not shown) of a mold clamping device via another member, and a flange 12 that protrudes outward in the X-axis direction from the fixed-side base 11. The fixed-side base 11 and the flange 12 are integrally molded with each other. Of course, the fixed mold 10 has various components (not shown) in addition to the fixed-side base 11 and the flange 12.

[0019] The flange portion 12 is provided at approximately the middle of the fixed base portion 11 in the Z-axis direction, and is formed in a ring shape that surrounds the fixed base portion 11. This flange portion 12 has a sufficient thickness, and forms part of the first positioning mechanism 3 that cooperates with the movable mold 30 to position the fixed mold 10 and the movable mold 30 before the filling step.

[0020] Specifically, the flange portion 12 has a plurality of through holes 13 (first recesses) spaced apart along the circumferential direction of the flange portion 12. Each through hole 13 penetrates the flange portion 12 in the thickness direction (Z-axis direction). The number of through holes 13 is not particularly limited, but it is preferable to provide, for example, three or more through holes 13 in order to suppress misalignment between the fixed mold 10 and the movable mold 30 in the X-axis and Y-axis directions. For ease of explanation, two through holes 13 are shown in FIG. 1.

[0021] A bushing 14 that is smaller than the inner dimension (inner diameter) of the through hole 13 is provided on the inner peripheral surface of the flange portion 12 that defines each through hole 13. The bushing 14 is press-fitted into the flange portion 12 from the negative Z-axis direction of each through hole 13, and is positioned opposite the protrusion 12a provided in the open portion on the positive Z-axis direction side. The bushing 14 defines the narrowest inner diameter of the through hole 13. The inner diameter of this bushing 14 is set slightly larger than the outer diameter of the pin 34 (first protrusion) of the movable mold 30, and prevents misalignment between the fixed mold 10 and the movable mold 30 while allowing the pin 34 to enter.

[0022] The fixed base 11 has a molding recess 15 that forms the cavity space 2 (see FIG. 5), and this molding recess 15 is open on the positive side of the Z axis. The molding recess 15 may be formed into an appropriate shape depending on the molded product to be molded. A gate 16a is provided in the center of the bottom 16 side of the fixed base 11, through which molten molding material (e.g., resin material) injected from the injection device 53 passes.

[0023] The side portion 17 of the fixed side base portion 11 is formed in a thick-walled cylindrical shape to increase the strength of the fixed mold 10, and protrudes from the bottom portion 16 in the positive direction of the Z axis. The molding recess 15 is formed in the area surrounded by the bottom portion 16 and the side portion 17. The side portion 17 protrudes in the positive direction of the Z axis further than the flange portion 12, and forms a fixed side protrusion 18 (second protrusion) that enters the movable mold 30 when the movable mold 30 moves. The inner surface of the fixed side protrusion 18 is tapered and continues from the side portion 17 on the bottom portion 16 side to form the molding recess 15.

[0024] On the positive side of the side portion 17 in the Z-axis direction is provided a material shielding mechanism 5 which cooperates with the movable mold 30 to form the outer periphery of the cavity space 2 (the flow end of the molding material) and blocks the molding material filled in the cavity space 2. The material shielding mechanism 5 in the fixed mold 10 has a shield 19, an elastic member 20 that elastically supports the shield 19, and an accommodation portion 21 that accommodates the shield 19 and the elastic member 20.

[0025] The shield 19 is formed in a ring shape that surrounds the side portion 17 of the fixed base portion 11. The upper surface of the shield 19 is a flat surface that is parallel to the X-axis and Y-axis directions. The lower surface of the shield 19 (the surface on the negative Z-axis side) is formed with a seat that houses and fixes one end of the elastic member 20. The radially inner side surface of the shield 19 is formed into a shielding surface 19a that is parallel to the Z-axis direction. The shielding surface 19a faces the cavity space 2 inside the shield 19.

[0026] The elastic member 20 may be, for example, a coil spring, and multiple elastic members may be arranged along the circumferential direction of the side portion 17 to elastically support the shield 19 along the Z-axis direction. Note that the elastic member 20 is not limited to a coil spring, and may be made of rubber, urethane, or the like, as long as sufficient elastic force (sealing properties of the shield 19) is ensured.

[0027] The accommodation portion 21 fixes the other end of the elastic member 20 and supports the shield 19 via the elastic member 20. The side peripheral surface 21a of the fixed-side protrusion 18, which constitutes the accommodation portion 21 and faces the blocking surface 19a of the shield 19, is formed parallel to the Z-axis direction and is in contact with the blocking surface 19a of the shield 19 with an appropriate frictional force. The blocking surface 19a and the side peripheral surface 21a of the shield 19 allow the shield 19 to slide in the Z-axis direction, and block the molding material filled in the cavity space 2 by narrowing the clearance.

[0028] The fixed side convex portion 18 (side portion 17) forms part of the second positioning mechanism 4 that cooperates with the movable mold 30 to position the fixed mold 10 and the movable mold 30 during the compression process. Specifically, the outer peripheral surface of the fixed side convex portion 18 is a tapered outer peripheral surface 22 (convex side tapered surface) that can contact the movable mold 30 and guide the movable mold 30 during the compression process.

[0029] The tapered outer peripheral surface 22 is formed in the range from the end face of the fixed side protrusion 18 on the Z-axis positive side to the flange portion 12, and over the entire circumferential direction of the fixed side protrusion 18. Therefore, the tapered outer peripheral surface 22 is disposed in a position adjacent to the inside of each through hole 13 of the flange portion 12. The tapered outer peripheral surface 22 is inclined in the Z-axis positive direction so as to narrow toward the center of the fixed mold 10. The inclination angle θ of the tapered outer peripheral surface 22 with respect to the Z-axis direction is O It is advisable to set it in the range of about 1° to 30°, for example.

[0030] On the other hand, the movable mold 30 includes, in a side cross-sectional view, a block-shaped movable base 31 provided on the positive side of the Z axis, a molding protrusion 32 protruding in the negative direction of the Z axis from the center of the movable base 31, and an outer protrusion 33 protruding in the negative direction of the Z axis from the outer periphery of the movable base 31. The molding protrusion 32, the movable base 31, and the outer protrusion 33 are molded integrally with one another.

[0031] The movable base 31 is fixed to a movable platen (not shown) of a mold clamping device directly or via another member. The movable base 31 extends in the X-axis and Y-axis directions and is formed in a block shape having an appropriate thickness in the Z-axis direction.

[0032] The outer protrusion 33 is formed in a cylindrical shape that surrounds the side of the molding convex portion 32, and holds therein pins 34 (first convex portions) that constitute part of the first positioning mechanism 3. The movable mold 30 has the same number of pins 34 arranged at intervals along the circumferential direction of the outer protrusion 33 in correspondence with the multiple (for example, four) through holes 13 of the fixed mold 10.

[0033] The outer protrusion 33 has a plurality of retaining holes 35 into which the pins 34 are inserted and retained. Each retaining hole 35 is formed at an appropriate depth from the end face of the outer protrusion 33 in the negative Z-axis direction. The movable mold 30 also has a plurality of screw insertion holes 36 that communicate with each retaining hole 35 and pass through the movable-side base 31 and the outer protrusion 33. A fixing bolt 37 for fixing the pin 34 is inserted into each screw insertion hole 36. The tip of each fixing bolt 37 is screwed into the pin 34, thereby firmly fixing the pin 34 to the movable mold 30.

[0034] Each pin 34 has a female screw portion 34a at its end facing the positive Z-axis direction, and this female screw portion 34a is threaded onto a fixing bolt 37 inside a retaining hole 35. As a result, each pin 34 is held by the movable mold 30 and protrudes in the negative Z-axis direction from the end face of the outer protrusion 33 facing the negative Z-axis direction. Each pin 34 is formed in a cylindrical shape with a constant outer diameter along the Z-axis direction (the direction in which the movable mold 30 advances and retreats), and the protruding end on the negative Z-axis direction side is formed with rounded corners.

[0035] The pins 34 have an outer dimension (outer diameter) slightly smaller than the inner diameter of the bushings 14 of the fixed mold 10, and are inserted into the through holes 13 when the movable mold 30 advances relative to the fixed mold 10. The first positioning mechanism 3 can stably position the fixed mold 10 and the movable mold 30 by inserting each pin 34 of the movable mold 30 into each through hole 13 of the fixed mold 10 when advancing before the filling step.

[0036] Furthermore, the movable mold 30 has a movable-side recess 38 (second recess) that constitutes part of the second positioning mechanism 4, formed by the movable-side base 31, the outer peripheral surface of the molding convex portion 32, and the inner peripheral surface of the outer protrusion 33. The movable-side recess 38 is the portion into which the fixed-side convex portion 18 of the fixed mold 10 enters when the movable mold 30 is clamped. The movable-side recess 38 runs around the outside of the molding convex portion 32 in the circumferential direction.

[0037] Furthermore, the movable mold 30 has a receiving portion 39 at the back of the movable-side recess 38 in the positive direction of the Z axis (toward the movable-side base portion 31), which constitutes part of the material shielding mechanism 5 and receives the elastic force of the shield 19 of the fixed mold 10. The receiving portion 39 has a predetermined thickness along the Z axis direction and is formed in a ring shape extending along the circumferential direction of the movable-side recess 38. The surface of the receiving portion 39 on the negative side of the Z axis is formed into a flat surface parallel to the X-axis and Y-axis directions in order to come into surface contact with the shield 19. Note that the mold device 1 may be configured without the receiving portion 39.

[0038] In the clamped state after the compression step, as the movable mold 30 advances relative to the fixed mold 10, the molding convex portion 32 forms a cavity space 2 between itself and the molding concave portion 15 of the fixed base 11. In this embodiment, in order to form the food cup container 100, the molding convex portion 32 has an end face facing the bottom 16 of the molding concave portion 15, and also has a tapered outer peripheral surface inclined at a predetermined angle relative to this end face.

[0039] The movable mold 30 is provided with a part of the second positioning mechanism 4 in the movable-side recess 38 into which the fixed-side protrusion 18 of the fixed mold 10 enters. Specifically, the inner peripheral surface that constitutes the movable-side recess 38 at the outer protrusion 33 of the movable mold 30 is provided with a tapered inner peripheral surface 40 (recess-side tapered surface) that can come into contact with the tapered outer peripheral surface 22 of the fixed-side protrusion 18. This allows the mold device 1 to accurately position the fixed mold 10 and the movable mold 30 using the second positioning mechanism 4 during the compression process.

[0040] The tapered inner peripheral surface 40 is formed in the range from the end face of the receiving portion 39 on the negative Z-axis direction side to the outer protruding portion 33, and over the entire circumferential direction of the outer protruding portion 33. Therefore, the tapered inner peripheral surface 40 is disposed in a position adjacent to the inside of each pin 34 of the outer protruding portion 33. The tapered inner peripheral surface 40 is inclined so as to widen outward from the movable mold 30 in the negative Z-axis direction. The inclination angle θ of the tapered inner peripheral surface 40 with respect to the Z-axis direction is set so that the tapered inner peripheral surface 40 and the tapered outer peripheral surface 22 come into surface contact with each other. I is the inclination angle θ of the tapered outer peripheral surface 22 O It is preferable that the inclination angle θ of the tapered inner peripheral surface 40 is equal to I and the inclination angle θ of the tapered outer peripheral surface 22 O may be different from each other, for example, the inclination angle θ I is the inclination angle θ O It may be set to be larger than

[0041] The mold apparatus 1 according to this embodiment is basically configured as described above, and its operation and effects will be described below. As shown in Fig. 3, in the compression molding method using the mold apparatus 1, a mold closing step (step S1), a filling step (step S2), a compression step (step S3), and a mold opening step (step S4) are carried out in this order by the operation of an injection molding machine. Note that the compression step does not necessarily have to be started after the filling step, but may be started during the filling step.

[0042] In the mold closing process, the movable mold 30 is advanced in the negative direction of the Z axis based on the operation of the operating unit 52, and moved to the filling position, thereby bringing the movable mold 30 into contact with the fixed mold 10. At this time, the injection molding machine detects the position and moving speed of the movable mold 30 using an encoder or the like, and accurately moves the movable mold 30 based on the detection results. As a result, as shown in FIG. 4(A), a filling space 6 that is larger than the cavity space 2 for molding the molded product is formed between the fixed mold 10 and the movable mold 30. Note that the injection molding machine may advance the movable mold 30 to the rear side of the fixed mold 10 beyond the filling position, and then perform an operation to retract the movable mold 30, thereby placing the movable mold 30 at the filling position.

[0043] As the movable mold 30 advances, the material shielding mechanism 5 causes the shield 19, which protrudes in the positive direction of the Z axis from the accommodation portion 21 of the fixed mold 10, to come into contact with the receiving portion 39 of the movable mold 30. The shield 19 is pressed in the negative direction of the Z axis by the receiving portion 39 of the movable mold 30, causing the elastic member 20 to contract and displacing toward the back of the accommodation portion 21. When the movable mold 30 is in the pre-compression position at the filling position, the space at the flow end (the outer periphery on the radially outer side) of the filling space 6 is surrounded by the fixed-side protrusion 18, the shield 19, and the receiving portion 39, and the outer end on the radial direction is blocked by the blocking surface 19a. This prevents the molding material from leaking from the outer periphery of the filling space 6 during the filling process, making it possible to prevent flash from occurring on the molded product.

[0044] Furthermore, in the mold closing process, the fixed mold 10 and the movable mold 30 are positioned by the first positioning mechanism 3 of the mold apparatus 1. Specifically, as the movable mold 30 advances relative to the fixed mold 10, the pins 34 protruding from the outer protrusion 33 of the movable mold 30 are inserted into the through holes 13 in the flange portion 12 of the fixed mold 10. This allows the mold apparatus 1 to position the fixed mold 10 and the movable mold 30 in the X-axis and Y-axis directions before the molding material is filled.

[0045] As described above, the outer diameter of the pin 34 is slightly smaller than the inner diameter of the bushing 14. Therefore, as shown in Fig. 4(B), when each pin 34 is inserted into each through hole 13, a first gap 3c is formed between the inner peripheral surface of the bushing 14 that defines each through hole 13 and the outer peripheral surface of each pin 34. The first gap 3c should be designed in advance to have an appropriate distance D1 (and cross-sectional area) that allows movement of each pin 34 in the Z-axis direction relative to the flange portion 12, while enabling the fixed mold 10 and the movable mold 30 to be positioned to some extent.

[0046] 4(C), a pre-compression second gap 4c1 is formed between the tapered outer peripheral surface 22 of the fixed-side convex portion 18 of the fixed mold 10, which constitutes the second positioning mechanism 4, and the tapered inner peripheral surface 40 of the outer protrusion 33 of the movable mold 30. In the pre-compression position, the distance D2a of the pre-compression second gap 4c1 is larger than the distance D1 of the first gap 3c. As a result, the mold apparatus 1 can position the fixed mold 10 and the movable mold 30 by the first positioning mechanism 3 without using the second positioning mechanism 4 before the filling step.

[0047] In the filling step, the injection device 53 (see FIG. 1) has moved to the bottom 16 of the fixed mold 10, and the molding material is filled into the filling space 6 through the gate 16a. At this time, the filling space 6, which has a larger volume than the cavity space 2, can smoothly guide the molding material into the interior. The molding material filled into the filling space 6 is heated inside the injection device 53, so that it remains in a liquid or semi-solid state during the filling step.

[0048] 5(A), the compression molding method performs a compression step in which the movable mold 30 is further advanced in the negative direction of the Z axis during or after the filling step, compressing the filled molding material. At this time, the movable mold 30 moves to the clamping position, forming a cavity space 2 for molding a molded product between the fixed mold 10 and the movable mold 30. As the molding material filled in the filling space 6 is compressed, it moves to the flow end where the material shielding mechanism 5 is provided.

[0049] As the movable mold 30 advances, the shield 19 of the material shielding mechanism 5 is pressed by the receiving portion 39 in the negative Z-axis direction and pushed toward the back of the storage portion 21. At this time, the shielding surface 19a of the shield 19 and the side peripheral surface of the storage portion 21 extend relative to each other in the Z-axis direction, allowing the shield 19 to slide smoothly and stably shield the molding material that has moved to the end of the flow. In particular, the clearance between the shielding surface 19a of the shield 19 and the side peripheral surface 21a of the storage portion 21, which extend in the Z-axis direction, can be minimized, making it possible to prevent vertical flash on the molded product. When the movable mold 30 is positioned at the mold clamping position and in a clamping-completed state, the mold apparatus 1 can mold a food cup container 100 having an integrated container bottom 101, container side 102, and container flange 103.

[0050] Then, in the compression step, the mold device 1 positions the fixed mold 10 and the movable mold 30 using the second positioning mechanism 4. Specifically, as the movable mold 30 advances relative to the fixed mold 10, the fixed-side convex portion 18 of the fixed mold 10 is inserted into the movable-side concave portion 38 of the movable mold 30. During this insertion, the tapered inner peripheral surface 40 of the outer protrusion 33 comes into contact with the tapered outer peripheral surface 22 of the fixed mold 10, and the movable mold 30 advances while the tapered outer peripheral surface 22 and the tapered outer peripheral surface 22 are in sliding contact with each other. This allows the fixed mold 10 and the movable mold 30 to be positioned with high precision in the X-axis and Y-axis directions.

[0051] 5(C), when the movable mold 30 has moved to the mold clamping position, the tapered outer peripheral surface 22 and the tapered inner peripheral surface 40 are in tapered surface contact with each other. That is, the distance D2b (and cross-sectional area) of the post-compression second gap 4c2 between the tapered outer peripheral surface 22 of the second positioning mechanism 4 and the tapered inner peripheral surface 40 is smaller than the pre-compression second gap 4c1 during the filling step, specifically, becomes zero. Because the distance D2b of the post-compression second gap 4c2 is smaller than the distance D1 of the first gap 3c of the first positioning mechanism 3, the mold apparatus 1 can accurately position the fixed mold 10 and the movable mold 30 during the compression step.

[0052] Furthermore, since the tapered outer peripheral surface 22 of the fixed mold 10 and the tapered inner peripheral surface 40 of the movable mold 30 each rotate endlessly, the second positioning mechanism 4 positions the molds relative to each other over the entire circumferential direction of the cavity space 2. This enables the second positioning mechanism 4 to advance the movable mold 30 while dispersing the stress applied to positioning in the X-axis and Y-axis directions (directions perpendicular to the advance / retract direction) during the compression process, and allows the core of the fixed mold 10 and the core of the movable mold 30 to smoothly align.

[0053] 5(B), the first gap 3c is maintained between the inner peripheral surface of the bushing 14 of each through hole 13 constituting the first positioning mechanism 3 and the outer peripheral surface of each pin 34 in the pre-compression position and in the filling process. In other words, the first positioning mechanism 3 continuously maintains the gap D1 between each through hole 13 that is sufficient to allow each pin 34 to pass through, so that the influence of the first positioning mechanism 3 as a positioning mechanism in the compression process is smaller than the influence of the second positioning mechanism 4.

[0054] During the operation of the die device 1, the relationship between the distance D1 of the first gap 3c, the distance D2a of the pre-compression second gap 4c1, and the distance D2b of the post-compression second gap 4c2 is expressed by the following formula (1).

[0055] D2a>D1>D2b …(1)

[0056] In this way, the mold apparatus 1 positions the fixed mold 10 and the movable mold 30 using the first positioning mechanism 3 before the filling step, and positions the fixed mold 10 and the movable mold 30 using the second positioning mechanism 4 during the compression step after the filling step. This allows the mold apparatus 1 to position the fixed mold 10 and the movable mold 30 with high precision while suppressing the load (for example, galling of the positioning mechanism) that occurs when positioning the fixed mold 10 and the movable mold 30, eliminating misalignment between the fixed mold 10 and the movable mold 30. As a result, the mold apparatus 1 prevents uneven thickness in the molded product molded in the compression step, avoiding various defects associated with uneven thickness, and enabling the mold apparatus 1 to successfully mold thin-walled molded products.

[0057] Then, in the mold opening process after the compression process, the injection molding machine operates the operating unit 52 to move the movable mold 30 from the clamping position in the positive Z-axis direction, thereby separating the movable mold 30 from the fixed mold 10. Thereafter, the injection molding machine completes the compression molding method by ejecting the molded product from the movable mold 30 using an ejector device (not shown). Note that the compression molding method may also be configured to perform a depressurization process, in which the movable mold 30 is slightly moved back from the clamping position to reduce the pressure in the cavity space 2, before the mold opening process, and then perform the mold opening process.

[0058] It should be noted that the mold apparatus 1 according to this embodiment is not limited to the above configuration, and various modifications are possible. For example, in the above embodiment, the first positioning mechanism 3 is configured so that the fixed mold 10 has a through hole 13 (first recess) and the movable mold 30 has a pin 34 (first convex portion), but this configuration may be reversed. Similarly, the second positioning mechanism 4 is configured so that the fixed mold 10 has a fixed-side convex portion 18 (second convex portion) and the movable mold 30 has a movable-side concave portion 38 (second concave portion), but this configuration may be reversed. In short, the relationship between the shapes of the fixed mold 10 and the movable mold 30 may be reversed.

[0059] The mold apparatus 1 according to the embodiment disclosed herein is illustrative in all respects and is not limiting. The embodiment can be modified and improved in various ways without departing from the spirit and scope of the appended claims. The matters described in the above-mentioned 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]

[0060] 1. Mold equipment 3 First positioning mechanism 4 Second positioning mechanism 10 Fixed mold (part of fixed mold) 30 Movable mold (part of the movable mold)

Claims

1. A mold device having a fixed mold and a movable mold that moves forward and backward relative to the fixed mold, a first positioning mechanism provided on the fixed mold and the movable mold, which positions the fixed mold and the movable mold before a filling step of filling a molding material; 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, the first positioning mechanism includes a first recess provided in one of the fixed mold and the movable mold, and a first protrusion provided in the other of the fixed mold and the movable mold, the second positioning mechanism includes a second recess provided in one of the fixed mold and the movable mold, and a second protrusion provided in the other of the fixed mold and the movable mold, a gap between the second recess and the second protrusion after the compression step is smaller than a gap between the first recess and the first protrusion; Mold equipment.

2. a gap between the second recess and the second protrusion before the filling step is larger than a gap between the first recess and the first protrusion; The mold apparatus according to claim 1 .

3. The first protrusion has a constant outer dimension along the advancing and retreating direction of the movable mold, The first recess has an inner dimension larger than an outer diameter of the first protrusion. The mold apparatus according to claim 1 or 2.

4. the second recess has a recess-side tapered surface, the second protrusion has a protrusion-side tapered surface that is in surface contact with the recess-side tapered surface; The mold apparatus according to any one of claims 1 to 3.

5. the recess-side tapered surface and the protrusion-side tapered surface are inclined with respect to the advancing / retracting direction of the movable mold and are formed over the entire circumference in a circumferential direction perpendicular to the advancing / retracting direction. The mold apparatus according to claim 4.

6. a material shielding mechanism that is provided closer to the center of the fixed mold and the movable mold than the first positioning mechanism and the second positioning mechanism, that constitutes an outer periphery of a cavity space formed by the fixed mold and the movable mold, and that blocks the molding material filled in the cavity space; The mold apparatus according to any one of claims 1 to 5.

7. the material shielding mechanism includes: a shield provided on one of the fixed mold and the movable mold so as to be able to advance and retreat; a housing portion for housing the shield; and a receiving portion provided on the other of the fixed mold and the movable mold, with which the shield comes into contact as the movable mold advances; a blocking surface of the blocking body and a side peripheral surface of the accommodation portion facing the blocking surface are formed parallel to the advancing and retreating direction of the movable mold; The mold apparatus according to claim 6.

8. A mold device having a fixed mold and a movable mold that moves forward and backward relative to the fixed mold, a first positioning mechanism provided on the fixed mold and the movable mold, which positions the fixed mold and the movable mold before a filling step of filling a molding material; 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, a material shielding mechanism that is provided closer to the center of the fixed mold and the movable mold than the first positioning mechanism and the second positioning mechanism, that constitutes an outer periphery of a cavity space formed by the fixed mold and the movable mold, and that blocks the molding material filled in the cavity space; the material shielding mechanism includes: a shield provided on one of the fixed mold and the movable mold so as to be able to advance and retreat; a housing portion for housing the shield; and a receiving portion provided on the other of the fixed mold and the movable mold, with which the shield comes into contact as the movable mold advances; a blocking surface of the blocking body and a side peripheral surface of the accommodation portion facing the blocking surface are formed parallel to the advancing and retreating direction of the movable mold; Mold equipment.

9. A molding apparatus comprising: the mold apparatus according to any one of claims 1 to 8; and an injection apparatus that fills the molding material into the mold apparatus. Injection molding machine.

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