JP2011031589A - Injection mold and injection molding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an undercut processing for manufacturing a molding annularly equipped with an undercut of an inward groove shape. <P>SOLUTION: A center core, and a plurality of first slide cores and second slide cores, alternately arranged along an outer side of the center core to surround the outer side thereof, are provided. The center core is moved back with an action of opening springs in the first half stage of a mold opening, the first slide cores are moved inside by an inside slide core system in the second half stage of the mold opening, and the second slide cores are moved with an action of an injection rod by an oblique slide system after the mold opening. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an injection mold and an injection molding method for producing a molded product in which an inward groove-like undercut is annularly provided.

  Some molded articles have an annular undercut. For example, a case such as a portable device or a notebook personal computer having a curved shape cannot be fixed by screws or the like because of product design. Therefore, in order to employ a fixing method for fitting the product body into the housing, an inward groove-shaped undercut is formed over the entire circumference of the housing. When taking out a molded product having such an undercut from a mold, there is a conventional technique in which a slide is moved inside the undercut with an angular pin (Patent Document 1).

  More specifically, as a mold for producing a molded product having an undercut over the outer periphery of a flat plate having a square shape in plan view, the movable mold has a core insert facing the cavity, and a periphery of the core insert. Some have a corner moving block and a side moving block. The corner moving block and the side moving block are supported by the core plate, while the core insert is supported by the core back plate. Then, after the mold is opened, the following steps (1) and (2) are performed in order to process the undercut.

  (1) First, the cylinder is driven. Then, the core plate rises with respect to the core back plate, and as a result, the corner moving block and the side moving block rise relative to the core insert, and the corner moving block and the side moving block A space for moving these moving blocks is created inside. In addition, when these moving blocks are raised relative to the core insert, the corner moving blocks are moved inward by finger pins (angular pins) toward the moving space.

  (2) Next, push up the ejector plate with the push-up rod. Then, the side portion moving block moves inward toward the movement space. As a result, all of these moving blocks have moved to the inside of the undercut of the molded product, and the molded product can be taken out.

JP 2000-94479 A

  However, in the technique described above, two steps are required after mold opening in order to process the undercut. Therefore, if there are fewer steps, the molding cycle can be shortened.

  In addition, if undercut processing can be performed without using a cylinder as much as possible, the cost of the mold can be kept low.

  The present invention has been created in view of the above circumstances, and its solution is to reduce the number of steps required for undercut processing after mold opening.

  In order to manufacture a molded product in which an inward groove-like undercut is provided in an annular shape, the movable mold includes a movable side mounting plate and a spacer block fixed to the mating surface side of the movable side mounting plate. A support plate fixed to the mating surface side of the spacer block, a center core fixed to the center portion of the mating surface side of the receiving plate, and a movable supported to be able to move forward and backward on the outer peripheral portion of the mating surface side of the receiving plate A side mold plate, and a plurality of first slide cores and second slide cores arranged alternately along the outside to surround the outside of the center core, the first slide core and the second slide core The slide core is fitted in the accommodating space between the center core and the movable side mold plate, and is fitted in a portion corresponding to the inner side of the undercut, so as to widen the gap between the movable side mounting plate and the receiving plate. Opening that gives opening force Provided with a step, and provided with a stop bolt for restricting the space between the movable side mold plate and the receiving plate, and after the molded product is cured, the center core is relatively retracted by an opening means, and then the first slide core, Assume an injection mold in which the two slide cores are sequentially moved inward.

  The opening means applies an opening force to the first half of the mold opening, and in order to move the first slide core by the inner slide core method in the second half of the mold opening, It has an engaging portion that protrudes outward from the undercut, and an angular pin is provided in one of the fixed mold and the engaging portion of the first slide core, and a fitting hole through which the angular pin enters and exits is provided in the other. It is characterized by providing.

  The opening means may use a cylinder, but in this case, the cylinder must be controlled so that the space between the receiving plate and the movable side plate is widened in the first half of the mold opening. In order to avoid such control and keep the cost of the mold low, it is desirable to do the following. That is, as in the invention of claim 2, the opening means is an opening spring.

  In addition, the method of moving the second slide core may use a cylinder. However, as in the case described above, in order to avoid the control and keep the cost of the mold low, the following should be performed. Is desirable. That is, as in the third aspect of the invention, the second slide core is moved by an inclined slide method.

  The invention of claim 4 is an injection molding method using the injection mold according to claim 1, 2 or 3, wherein the distance between the movable side mold plate and the receiving plate is widened in the first half of the mold opening. The center core retreats relative to the first slide core and the second slide core to form a gap for movement. In the latter half of the mold opening, the angular pin is a fitting hole of the first slide core. The first side core is moved inward while being removed from the mold, and the second slide core is moved inward of the undercut after the mold is opened.

  According to the present invention, when the opening means applies an opening force, the center core moves backward relative to the first and second slide cores in the first half of the mold opening, and the first slide core A moving space for moving the inside is formed. In the latter half of the mold opening, the first slide core is moved inward by the inner slide core method. Therefore, only the second slide core needs to be moved after the mold opening. Therefore, the process required for the undercut process after the mold opening is only one process for moving the second slide core, and the molding cycle can be shortened.

  If the opening means is an open spring, the center core moves backward in the first half just by opening the mold, so it is not necessary to control the cylinder, and the cost of the mold is kept low. be able to.

  If the second slide core is moved by the inclined slide method, the cylinder is not used, and it is not necessary to control the cylinder, and the cost of the mold can be kept low.

FIGS. 3A and 3B are cross-sectional views taken along the line A-A in FIG. FIG. 4 is a cross-sectional view taken along the line AA in FIG. It is the front view which looked at the injection mold from the fixed mold side. FIGS. 3A and 3B are cross-sectional views taken along the line B-B in FIG. FIGS. 3A and 3B are cross-sectional views taken along the line B-B in FIG. 3 and show an injection mold in the latter half of the mold opening stage and an ejecting process by an ejector. FIG. 4 is a cross-sectional view taken along line B-B in FIG. 3 and shows an injection mold when a molded product is taken out. (A) to (f) are flowcharts showing an outline of undercut processing. (A), (B), and (C) are a front view, a right side view, and a plan view showing a lock unit that regulates that the widened gap between the receiving plate and the movable side mold plate is narrowed.

  The molded product 9 manufactured by the injection mold is not only a resin but a molded product made of a metal such as magnesium. As shown in FIG. 6 or FIGS. 7 (a) and 7 (b), the structure protrudes on one side of the main body 91, which is a square plate in plan view, and the entire outer edge of the outer periphery of the main body 91. And a ring-shaped protrusion 93 that protrudes inwardly from the entire periphery of the lower end of the side section 92. An inward groove-like undercut 94 is formed in an annular shape by the outer peripheral edge of the main body 91, the side 92, and the protrusion 93. A hollow portion 95 is formed inside the main body portion 91 and the undercut 94.

  The injection mold is composed of a fixed mold 1 and a movable mold 2 as shown in FIG. Hereinafter, in order, for convenience, the cavity formed by the fixed mold 1 and the movable mold 2 may be referred to as a mating surface side, and the opposite side may be referred to as a counter mating surface side. FIG. 3 shows the positional relationship of the molded product 9 when the injection mold is viewed from the fixed mold side.

  As shown in FIG. 1, the fixed mold 1 includes a fixed side mounting plate 11 that is fixed to a fixed plate of the molding machine with bolts, and a fixed side mold plate 12 that is fixed to a mating surface of the fixed side mounting plate 11. ing. The fixed-side template 12 is formed with a receiving hole 12a for receiving the head of the locking block 36 outside the cavity. The locking block 36 is fixed to the stationary template 12 with a bolt (not shown) while the head is accommodated in the accommodation hole 12a. At this time, the tip of the locking block 36 protrudes toward the movable mold 2 from the mating surface. Although not shown, the fixed mold 1 includes a gate, a runner, a sprue, and the like that continue to the cavity.

  The movable mold 2 includes a movable side mounting plate 21 that is fixed to a movable platen of the molding machine with bolts, spacer blocks 22 that are fixed at a plurality of locations around the mating surface side of the movable side mounting plate 21, and these spacer blocks 22. The receiving plate 23 is fixed to the mating surface side. The receiving plate 23 faces the movable side mounting plate 21 with a gap. Further, a guide pin 24 fixed at a plurality of positions around the mating surface side of the receiving plate 23 and a movable side mold plate 25 movable along the guide pin 24 (movable forward and backward) are also provided. In the mold clamping state, the tip portion of the guide pin 24 protrudes into the fixed side mold plate 12, and therefore, the guide hole 12 b that guides the guide pin 24 to the fixed side mold plate 12 and the movable side mold plate 25. 25a are formed. Accordingly, the movable side mold plate 25 is supported on the outer peripheral portion of the receiving plate 23 on the mating surface side so as to be able to advance and retreat.

  The movable mold 2 also includes a center core 26 and a plurality of first slide cores 27 and second slide cores 28 surrounding the center core 26. In order to surround and position the first slide core 27 and the second slide core 28 from the outer peripheral side, the outer peripheral portion of the movable side template 25 protrudes toward the mating surface. In the outer peripheral portion, the portion corresponding to the first slide core 27 protrudes to the outside of the undercut 94, more specifically, to the outside of the locking block 36. On the other hand, as shown in FIG. 4, the portion corresponding to the second slide core 28 in the outer peripheral portion protrudes until reaching the outer surface of the side portion 92 and the bottom surface of the protruding portion 93 of the molded product 9. An accommodation space 25b is formed between the outer peripheral portion and the center core 26, and the first slide core 27 and the second slide core 28 are alternately fitted in the accommodation space 25b along the circumferential direction in the clamping state. Is positioned.

  As shown in FIG. 7, the mating surface side of the center core 26 corresponds to the central portion of the hollow portion 95 of the molded product 9, so to speak, is a shape with four corners chamfered. And an octagonal shape formed by chamfered four sides with short corners.

  The mating surface side of the first slide core 27 corresponds to a side portion of the outer peripheral portion of the hollow portion 95 of the molded product 9, so to speak, is a trapezoidal shape whose width increases toward the inside. It touches one of the four sides. In FIG. 7, only the portion corresponding to the inside of the molded product 9 is shown on the mating surface side of the first slide core 27, but as shown in FIG. 1, the portion corresponding to the outside of the molded product 9. There is also.

  The second slide core 28 corresponds to the corner portion of the outer peripheral portion of the hollow portion 95 of the molded product 9, and the inclined sides on both sides of the two adjacent first slide cores 27 and the corner angle of the center core 26. It touches the side. As shown in FIG. 3, the second slide core 28 is only a portion corresponding to the inside of the molded product 9.

  First, an outline of the undercut process will be described. FIG. 7 (a) shows a state immediately after the molded product 9 is formed. FIG. 7 (b) shows that the first slide core 27 and the second slide core 28 surround the center core 26 at this time. A state in which the first slide core 27 and the second slide core 28 are fitted in the inward groove of the undercut 94 is shown. FIG. 2C shows that a movement gap is formed by retracting the center core 26 first. FIG. 2B shows that a gap for moving the second slide core 28 is formed by moving the first slide core 27 inward. FIG. 5E shows that the undercut process is completed by moving the second slide core 28 inward. FIG. 6F shows that the molded product 9 is finally removed.

  As shown in FIG. 1, the center core 26 is fitted into a concave portion 23 a formed at the center portion on the mating surface side of the receiving plate 23, fixed with a bolt or the like, and protrudes toward the mating surface side. This protruding portion passes through the through-hole 25 c in the central portion of the movable side mold plate 25 and fits into a portion corresponding to the central portion in the hollow portion 95 of the molded product 9.

  The first slide core 27 is fitted into the side portion of the hollow portion 95 of the molded product 9 and the front portion of the locking block 36. For this reason, on the mating surface side of the first slide core 27, a first convex portion 27a that fits inside the side portion of the undercut 94 and an accommodation hole 27c that fits at the tip of the locking block 36 are formed. Yes.

  As shown in FIG. 4, the second slide core 28 is fitted into a portion corresponding to a corner portion in the hollow portion 95 of the molded product 9. For this reason, on the mating surface side of the second slide core 28, the second convex portion 28 a that fits in the corner portion of the undercut 94 projects outward.

  In order to make the center core 26 retractable from the mating surface side, the outer peripheral surface of the center core 26 and the inner peripheral surfaces of the first slide core 27 and the second slide core 28 are in contact with each other at an inclined surface. . More specifically, as shown in FIG. 1 or FIG. 4, an inclined surface having a divergent shape is provided on the outer peripheral surface of the front portion of the center core 26 when viewed from the side, and the first slide core 27 and the first An inclined surface corresponding to the second slide core 28 is also provided.

  In order to retract the center core 26 in the first half of the mold opening, the movable mold 2 includes an open spring 29 (compression coil spring) between the receiving plate 23 and the movable mold plate 25. The release spring 29 is accommodated in a contracted state in the mold clamping state, and serves as an opening means that widens the interval between the receiving plate 23 and the movable side mold plate 25 during mold opening, that is, provides an opening force. . An accommodation hole 29 a for an open spring is formed on each facing surface of the receiving plate 23 and the movable side mold plate 25.

  The movable mold 2 includes two ejector plates 31 and 32 integrated with bolts on the mating surface side of the movable mounting plate 21, and between the ejector plate 31 and the receiving plate 23 on the mating surface side. A return spring 33 is provided. An accommodation hole 33a for the return spring is formed on each opposing surface of the ejector plate 31 and the receiving plate 23. When the opening spring 29 for retreating the center core 26 widens the distance between the receiving plate 23 and the movable side mold plate 25 by the restoring force, the return spring 33 contracts and moves these ejector plates 31 and 32 to the mating surface side. Let

  The movable mold 2 includes a stop bolt 34 that protrudes from the receiving plate 23 toward the movable side mold plate 25. The stop bolt 34 regulates the interval between the receiving plate 23 and the movable side mold plate 25 by the opening spring 29. A receiving hole 34 a for a stop bolt is formed on each facing surface of the receiving plate 23 and the movable side mold plate 25. One side (the receiving plate side in the figure) of the stop hole 34a for the stop bolt is a female screw hole, and the tip of the shaft portion of the stop bolt 34 is screwed. The opposite side (movable side mold plate side in the figure) of the stop hole 34a for the stop bolt is a through hole, the diameter of the through hole is larger than the shaft portion of the stop bolt 34, and the mating surface side of the through hole Is a counterbore that the head of the stop bolt 34 can move. The distance from the head of the stop bolt 34 to the bottom of the counterbore in the mold-clamping state is the interval between the receiving plate 23 and the movable side mold plate 25. The stop bolt receiving hole 34a is concentrically provided so as to pass through the open spring receiving hole 29a.

  Further, in order to enable the first slide core 27 to move inward with the center core 26 retracted, the first slide core 27 and the second slide core 28 are also inclined with respect to each other as shown in FIG. It touches. More specifically, when viewed from the mating surface side, the first slide core 27 is provided with inclined surfaces having a shape that widens inward on both sides in the width direction, and an inclined surface corresponding to the inclined surface is provided. The second slide core 28 is provided.

  Further, in order to move the first slide core 27 inward in the latter half of the mold opening, an inner slide core system is adopted. That is, the angular pin 35 protrudes from the stationary side template 12 and the angular pin 35 is fitted to the first slide core 27. As described above, the mating surface side of the first slide core 27 is fitted into the side portion of the undercut 94, but the inner side of the undercut 94 is a portion related to the tip of the center core 26, and the undercut is made. The outer side portion than 94 is an engaging portion 27 b related to the angular pin 35. A fitting hole 35a into which the angular pin 35 is fitted is formed on the mating surface side of the engaging portion 27b. On the other hand, the angular pin 35 has its head side accommodated in a counterbore hole of the locking block 36, and its shaft portion side protrudes from the locking block 36. The angular pin 35 is inclined inward toward the tip, and the fitting hole 35a into which the angular pin 35 is fitted is also the same. Due to these inclinations, the first slide core 27 moves inward as the angular pin 35 comes out of the fitting hole 35a. The locking block 36 and the receiving hole 27c into which the tip of the locking block 36 fits are also provided with the same inclination in order to avoid interference during mold clamping and mold opening.

  After opening the mold, as shown in FIG. 5 (B), an inclined slide system is adopted to move the second slide core 28 inward by the pushing-up action of the protruding rod R. That is, the second slide core 28 is an inclined slide. A slide unit 37 is provided on the ejector plate 31 on the mating surface side. The slide unit 37 is a well-known T-shaped piece that can move inward and outward, and a thrust plate that serves as a rail when the piece moves in parallel. A piece is accommodated in an empty portion provided in the ejector plate 31 so as to be movable inward and outward, and two thrust plates are fixed in parallel to each other on the mating surface side of the ejector plate 31. Then, the piece of the slide unit 37 and the second slide core 28 are connected by the slide rod 38 using the distance between the two thrust plates. The slide rod 38 is inclined in the direction toward the outside as it is away from the mating surface. A guide hole 38a is formed in the movable side mold plate 25, and the guide hole 38a guides the slide rod 38 so as to be movable along the inclination direction. On the other hand, a hole 38 b through which the slide rod 38 is inserted is formed in the receiving plate 23. The diameter of the hole 38b is formed large so as not to interfere with the slide rod 38 when the distance between the movable side mold plate 25 and the receiving plate 23 is widened. When the projecting rod R is pushed up and the second slide core 28 is moved inward, the undercut process is completed.

  In addition, the fixed mold 1 and the movable mold 2 are provided with a lock unit 4 that restricts the interval between the receiving plate 23 and the movable mold plate 25 from being narrowed. When the lock unit 4 is clamped, the first slide core 27 and the second slide core 28 move to the outside of the accommodation space 25b until the space for the center core 26 is formed inside thereof. This makes it impossible for the center core 26 to move forward.

  As shown in FIGS. 1 and 8, the lock unit 4 is swingable on a shaft 42 between a U-shaped bracket 41 fixed to the side surface of the receiving plate 23 and two support pieces of the bracket 41. A lock arm 43 to be supported is provided. The lock arm 43 projects a claw 43a on the inner side of the swing side end, and the claw 43a enters and exits between the receiving plate 23 and the movable side mold plate 25 according to the state of mold clamping and mold opening. Further, a support shaft (bolt) 44 that protrudes outward from the receiving plate 23 and passes through the middle portion in the longitudinal direction of the lock arm 43, a pressing member (compression coil spring) 45 that passes outside the shaft portion of the support shaft 44, and a pressing member And a washer 46 for holding the outer surface side of 45 on the head side of the support shaft 44. The pressing member 45 presses the lock arm 43 toward the movable side mold plate 25 in the mold clamping state.

  Further, the lock unit 4 includes a lock pin 47 that is fixed in parallel with the shaft 42 at the swing end of the lock arm 43, and a rod-like key 48 that can press the lock pin 47. The key 48 is fixed to the side surface of the fixed-side mold plate 12 and extends toward the lock arm 43, and moves forward and backward with mold clamping and mold opening. The tip portion of the key 48 has a tapered shape whose outer surface is an inclined surface, and this inclined surface hits the lock pin 47 when the mold is clamped and opened as shown in FIG. Smooth rocking motion.

  As shown in FIG. 2, the key 48 is separated from the lock pin 47 in the mold open state, and the rocking end of the lock arm 43 is pushed toward the movable side mold plate 25 by the restoring force of the pressing member 45. . Then, the claw 43 a of the lock arm 43 enters the space between the spread receiving plate 23 and the movable mold plate 25. Thus, the interval between the receiving plate 23 and the movable side mold plate 25 is restricted from being narrowed until the angular pin 35 is fitted into the fitting hole 35a. At this time, a slight gap is formed between the claw 43a and the counter mating surface side of the movable side template 25.

  The injection molding method using the above-described injection mold is performed as follows. For convenience of the drawings, description will be made from a state where the mold is clamped. (1) First, the dissolved material is injected into the cavity. At this time, as shown in FIGS. 1 (a) and 4 (a), the space between the receiving plate 23 and the movable side mold plate 25 is closed, and the periphery of the center core 26 is surrounded by the first slide core 27 and the second slide core 27. The slide core 28 is surrounded. Then, the release spring 29 contracts and the angular pin 35 is fitted in the fitting hole 35a. Further, the slide rod 38 is located inside the punched hole 38 b of the receiving plate 23, and the piece of the slide unit 37 is located outside the ejector plates 31 and 32. (2) When the material cools and hardens, the mold is opened.

(3.1) In the first half of the mold opening, as shown in FIG. 1 (b), the receiving plate 23 is moved away from the movable side mold plate 25 by the restoring force that the movable side mounting plate 21 is retracted and the release spring 29 is extended. Leave. At this time, the movable side mold plate 25 and the fixed side mold plate 12 remain abutted against each other. Then, the center core 26 fixed to the movable side mold plate 25 moves backward from the mating surface side. By this retreat, a gap for movement is formed inside the first slide core 27 and the second slide core 28. Further, the head of the stop bolt 34 hits the bottom of the counterbore of the accommodation hole 34a, and the interval between the receiving plate 23 and the movable side mold plate 25 is restricted.

(3.2) When the receiving plate 23 is separated from the movable side mold plate 25, the key 48 moves backward relative to the lock arm 43. Since the restoring force of the pressing member 45 is always applied to the lock arm 43, as the key 48 moves backward, the lock pin 47 moves from the outer surface of the intermediate portion of the length of the key 48 to the inclined surface of the front portion and 43 swings inward, and the claw 43a enters the widened space between the receiving plate 23 and the movable side mold plate 25, and the claw 43a restricts the movable side mold plate 25 from moving toward the receiving plate 23 side.

(3.3) When the receiving plate 23 moves away from the movable side mold plate 25, the second slide core 28 is accommodated in the accommodating space 25b of the movable side mold plate 25 as shown in FIG. Therefore, the receiving plate 23 comes close to the two ejector plates 31 and 32 integrated with the second slide core 28. Therefore, when the release spring 29 is extended, the return spring 33 contracts. Further, the slide rod 38 moves to the outside of the hole 38b of the receiving plate 23.

(4) In the latter half of the mold opening, as shown in FIG. 2, the movable side mounting plate 21 is further retracted, and the angular pins 35 fixed to the fixed side mold plate 12 are fitted into the fitting holes 35 a of the first slide core 27. The first slide core 27 is moved inwardly in the accommodation space 25b while getting out of the storage space 25b. At this time, as shown in FIG. 5A, the second slide core 28 remains fitted in the accommodation space 25b.

  (5) After opening the mold, as shown in FIG. 5B, the ejector rod R projects from the movable mounting plate 21 and the ejector plates 31 and 32 are pushed in. Then, the second slide core 28 moves in the direction of the fixed side template 12 while moving inward. At this time, the return spring 33 further contracts, and the piece of the slide unit 37 moves to the inside of the ejector plates 31 and 32. This completes the undercut process. (6) Then, as shown in FIG. 6, the molded product 9 is taken out.

  (7) Next, mold clamping is performed. (7.1) When the projecting rod R is retracted for that purpose, the second slide core 28 is moved outward by the restoring force of the return spring 33, and is fitted into the corner of the accommodating space 25b of the movable side mold plate 25. . (8) Thereafter, the movable mold 2 is advanced. While the angular pin 35 enters the fitting hole 35 a of the first slide core 27, the first slide core 27 is fitted into the side portion of the accommodation space 25 b of the movable side template 25. At this time, the fixed side template 12 and the movable side template 25 are brought into contact with each other.

  (9) The movable mold 2 is further advanced. By utilizing the gap between the claw 43a of the lock arm 43 and the movable side mold plate 25, the key 48 is also reduced while the interval between the receiving plate 23 and the movable side mold plate 25 is narrowed against the restoring force of the release spring 29. The lock pin 47 is pushed in along the inclined surface of the tip of the key 48 and moves outward. Then, the lock arm 43 to which the lock pin 47 is fixed swings outward, and the claw 43 a of the lock arm 43 comes out from between the receiving plate 23 and the movable side mold plate 25. When the claw 43a comes out, there is no obstacle when narrowing the space between the receiving plate 23 and the movable side mold plate 25. (10) The movable mold 2 is further advanced. Then, the movable side mold plate 25 and the receiving plate 23 overlap with each other, and the center core 26 is fitted into the space surrounded by the first slide core 27 and the second slide core 28. At this time, the ejector plates 31 and 32 are moved toward the movable mounting plate 21 by the action of the return spring 33.

  The present invention is not limited to the above embodiment. For example, the shape of the undercut 94 is not particularly limited as long as it is annular, and may be other polygonal shapes or circular shapes. Moreover, even if it says that it is cyclic | annular, it may not be completely continuous but may have a discontinuous part. Furthermore, although the 1st slide core 27 and the 2nd slide core 28 have attached the inclined surface so that it may come out in order of the side part of the molded article 9, and a corner part, it is not restricted to this. That is, the method of attaching the inclined surface is reversed so that the corner 9 and the side of the molded product 9 are removed in this order, and in this case, the one corresponding to the corner corresponds to the first slide core 27 and the side. The second slide core 28 may be used.

  In the above embodiment, the cavity is formed only by the fixed mold 1 and the movable mold 2, that is, a standard injection molding method that does not use an insert, but the cavity is formed by the fixed mold 1 and the movable mold. 2 and an insert may be used, that is, an insert may be used. When using an insert, the melted material is injected into the cavity after the insert is fixed to the fixed mold side or the movable mold side. Various materials such as plastic, metal, and ceramic can be considered as the material of the insert.

1 fixed mold
11 fixed side mounting plate 12 fixed side mold plate 12a receiving hole 12b guide hole 2 movable mold 21 movable side mounting plate 22 spacer block 23 receiving plate 23a recess 24 guide pin
25 movable side template 25a guide hole 25b accommodating space 25c through hole 26 center core
27 1st slide core 27a 1st convex part 27b engaging part 27c accommodation hole 28 2nd slide core 28a 2nd convex part 29 release spring (opening means) 29a accommodation hole 31 ejector plate 32 ejector plate 33 return spring 33a receiving hole 34 stop bolt 34a receiving hole 35 angular pin 35a fitting hole 36 locking block 37 slide unit 38 slide rod 38a guide hole 38b extraction hole 4 lock unit
41 bracket 42 shaft 43 lock arm 43a claw 44 support shaft 45 pressing member 46 washer 47 lock pin 48 key R protruding rod 9 molded product 91 main body portion 92 side portion 93 protrusion portion 94 undercut 95 cavity portion

Claims (4)

In order to produce a molded product (9) in which an inward groove-like undercut (94) is provided in an annular shape
The movable mold (2) is fixed to the movable side mounting plate (21), the spacer block (22) fixed to the mating surface side of the movable side mounting plate (21), and the mating surface side of the spacer block (22). The support plate (23), the center core (26) fixed to the center of the mating surface of the support plate (23), and the outer periphery of the mating surface of the support plate (23) are supported so as to be able to advance and retreat. A plurality of first slide cores (27) and second slide cores (28) alternately arranged along the outer side of the movable side mold plate (25) and the center core (26) to surround the outer side And the first slide core (27) and the second slide core (28) are fitted into the accommodating space (25b) between the center core (26) and the movable side mold plate (25) and are under. Fits into the part corresponding to the inside of the cut (94)
An opening means (29) is provided between the movable side mounting plate (21) and the receiving plate (23) to provide an opening force for widening the distance between them, and the movable side mold plate (25) and the receiving plate (23). And a stop bolt (34) that regulates the distance between the center core (26) and the center core (26) is relatively retracted by the opening means (29) after the molded product (9) is cured, and then the first slide core ( 27) An injection mold for moving the second slide core (28) inward in order,
The opening means (29) gives an opening force to the first half of the mold opening,
In order to move the first slide core (27) by the inner slide core method in the latter half of the mold opening, the first slide core (27) has an engaging portion protruding outward from the undercut (94). (27b), an angular pin (35) on one of the fixed mold (1) and the engaging portion (27b) of the first slide core (27), and an angular pin (35) on the other. An injection mold having a fitting hole (35a) for entering and exiting.   2. The injection mold according to claim 1, wherein the opening means (29) is an open spring.   The injection mold according to claim 2, wherein the second slide core (28) is moved by an inclined slide method. An injection molding method using the injection mold according to claim 1, 2 or 3,
In the first half of the mold opening, the distance between the movable side mold plate (25) and the receiving plate (23) is increased so that the center core is relatively located with respect to the first slide core (27) and the second slide core (28). (26) retreats to form a gap for movement;
In the second half of the mold opening, the first slide core (27) is moved inward while the angular pin (35) comes out of the fitting hole (35a) of the first slide core (27),
An injection molding method, wherein the second slide core (28) is moved inward of the undercut (94) after the mold is opened.

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