JP2007098809A - Method for molding resin molded article and molding mold - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for molding a resin molded article and a molding mold which prevent gloss unevenness and the like by avoiding the interference between an ejection mechanism part for a general use and an ejection mechanism part for a fine hole, and simplify the adjusting work of an ejector pin. <P>SOLUTION: The molding mold 40 comprises upper and lower molds 50, 60 capable of clamping and opening, and the ejection mechanism part 70 for the general use and the ejection mechanism part 80 for the fine hole provided in the lower mold 60. In the ejection mechanism part 80 for the fine hole, spring pressure of a spring 83 can be set low by driving an ejector plate 81 using both the spring 83 and a urethane bushing 84 which is to be pulled up to an ejector plate 71 of the ejection mechanism part 70 for the general use, so that the adjusting work of the eject pin 73 is simplified and a molding defect such as the gloss unevenness is prevented by avoiding the interference between the ejection mechanism part 70 for the general use and the ejection mechanism part 80 for the fine hole. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a molding method and a molding die for a resin molded product having a plurality of fine holes, and in particular, by improving the structure of the protruding mechanism portion of the molding die, the projecting step after molding the resin molded product. The present invention relates to a method for molding a resin molded product and a molding die that can be smoothly advanced.

  FIG. 8 is a front view showing a two-tone type automobile door trim 1 attached to the interior side of the door trim of the automobile. The two-tone type door trim 1 is composed of a door trim upper 2 and a door trim lower 3 divided into upper and lower parts. It is configured. And as shown in FIG. 9, the door trim upper 2 is comprised by sticking the skin 2b on the surface of the resin core material 2a, and the door trim lower 3 is comprised from the synthetic resin single-piece | unit. The door trim 1 is manufactured by forming the door trim upper 2 and the door trim lower 3 with separate molding dies and then assembling them. At this time, in order to form the speaker grille 3a integrally with the door trim lower 3, for example, a molding die 4 shown in FIG. 10 has been conventionally used.

  The molding die 4 includes a molding upper die 5 that can move up and down by a predetermined stroke, and a molding upper die 5 and a molding lower die 6 that are clamped. The molding upper die 5 is driven by a lift cylinder 5a for a predetermined stroke. While performing the up-and-down operation, the molding lower mold 6 is provided with a manifold 6a and a gate 6b that become resin passages, and molten resin is supplied into the cavity from an injection machine (not shown) through these resin passages. In particular, a punching block 6c is fitted into the molded lower mold 6 in order to form a fine hole like the speaker grill 3a. Furthermore, in order to remove the door trim lower 3 from the molded lower mold 6 after the door trim lower 3 is molded by clamping the molded upper and lower molds 5, 6, a two-stage protruding process has been conventionally employed. That is, in order to carry out the two-stage projecting process, a general projecting mechanism 7 for projecting a general portion and a microhole projecting mechanism 8 for projecting a microhole, such as the speaker grill 3a, are required. It is. Specifically, in the general projecting mechanism portion 7, the ejector plate 7a moves up and down by a predetermined stroke, usually about 120 mm, by the drive cylinder 7b. A projecting pin 7c and an angular pin 7d are connected to the ejector plate 7a, and after the door trim lower 3 is formed, the door trim lower 3 is pushed upward. Further, as for the protrusion of the minute hole such as the speaker grille 3a, the protrusion mechanism portion 8 for the minute hole is supported by the ejector plate 8a with a small diameter pin 8b, and the small diameter pin 8b projects about 30 mm. The ejector plate 8a is always urged upward by the spring 8c. For example, Patent Document 1 describes in detail a molding method and a molding die for a door trim including a speaker grill.

Japanese Patent Laid-Open No. 11-268046

  Thus, conventionally, in order to form the speaker grille 3a composed of micro holes, the micro hole projecting mechanism portion 8 configured to urge the plate 8a upward by a plurality of springs 8c is used as a general projecting mechanism portion 7. However, since the spring pressure of the spring 8c is strong, the ejector plates 7a and 8a in both the mechanism portions 7 and 8 interfere with each other, and the general ejector plate 7a is in the upper position as shown in FIG. It has been pointed out that the general protruding pin 7c protrudes upward, which adversely affects fine adjustments such as the balance and return of the protruding pin 7c.

  As described above, the protrusion of the protruding pin 7c and the adjustment man-hours associated therewith are required, and the management is troublesome. If the protruding pin 7c protrudes even slightly, the unevenness of gloss on the product surface of the door trim lower 3 It is urgent to avoid interference between the general protruding mechanism portion 7 and the fine hole protruding mechanism portion 8.

  The present invention has been made in view of such circumstances, and is a method of molding a resin molded product having a plurality of fine holes, such as the speaker grill 3a in the door trim lower 3, and includes a general part of the resin molded product and Adopting the method of projecting the micro hole part separately in two stages, and the interference between the general projecting mechanism part and the micro hole projecting mechanism part can be surely avoided, so that the projecting of the general projecting pin and the accompanying It is an object of the present invention to provide a molding method and a molding die for a resin molded product that can reduce the adjustment step, improve the balance between the protruding and returning of the protruding pin, and prevent molding defects.

  In order to solve the above-mentioned problems, the present invention is a method for molding a resin molded product having a plurality of fine holes, wherein after molding the upper and lower molds are clamped, a molten resin is injected and filled into the cavity, and a plurality of fine After molding the resin molded product with holes into the required shape, for the fine holes, a protruding process with a small diameter pin is adopted, and for the general part, a protruding process with a general protruding pin is adopted, and each of the small diameter pin and the protruding pin In the molding method of a resin molded product that performs ejection with different projecting strokes, the ejector plate in the projecting process of the small-diameter pin is generally transmitted through the spring pressure of the spring and a urethane bush attached to the ejector plate. The spring pressure of the spring is adjusted to a small level by the lifting operation with the tensile force from the ejector plate. Because it is a general use projecting mechanism, characterized in that as interference with the fine holes for projecting mechanism is avoided.

  Further, the molding die used in the present invention is a molding die of a resin molded product used for molding a resin molded product having a plurality of fine holes, and the molding die is clamped and opened. Providing a moldable upper / lower mold, a general protruding mechanism for protruding a general part of a resin molded product upward, and a fine hole protruding mechanism for locally protruding a fine hole in a resin molded product The part is moved up and down by the ejector plate, and the small-diameter pin pushes the fine hole in the resin molded product upward by a short stroke, and the ejector plate is spring-biased upward by a spring with a low spring pressure. And a urethane bush for raising the ejector plate in conjunction with the raising operation of the ejector plate of the general projecting mechanism. .

  Here, in the resin molded product having a plurality of fine holes, the fine holes can be applied to a speaker grille, and the resin molded products can be applied to an automobile door trim, a rear parcel shelf, and the like. In addition, the molding upper mold in the molding die can be moved up and down by a predetermined stroke by driving the lifting cylinder, and when the molding upper mold descends to the bottom dead center, the mold is clamped between the molding lower mold and desired A cavity having a shape can be formed, and a resin molded product can be formed into a required shape. On the other hand, the molding lower mold is provided with a manifold and a gate serving as a resin passage for a molten resin supplied from an injection machine, and is supplied to a predetermined portion of the molding surface of the molding lower mold through the resin passage.

  Accordingly, the supply timing of the molten resin may be performed after the upper and lower molds are clamped or may be performed before the mold clamping. The molded lower mold is supported between the spacer blocks on the base plate, and a protruding mechanism portion for a resin molded product is housed in a space formed by the spacer blocks. There are two types of projecting mechanism parts for resin molded products: general projecting mechanism parts that push up the entire length of the resin molded product with a long stroke, and microscopic hole projecting mechanism parts that push up micro holes such as speaker grills with a short stroke. The projecting mechanism part is supported by ejector plates that can move up and down by a predetermined stroke by a cylinder, and a pin, an angular pin, or the like is supported. Usually, the resin molded product can be projected upward by an upward operation of about 120 mm. .

  On the other hand, since the protruding mechanism for fine holes is a small diameter pin of about φ20 as the protruding pin, in order to avoid breakage, it is a protruding operation of only a short stroke of about 30 mm. The ejector plate in the mechanism part is provided with a spring and a urethane bush with a small spring pressure. The urethane bush fits into the ejector plate in the general projecting mechanism part and is pulled by the ejector plate in the general part. It is done. Therefore, since the tensile force from the ejector plate of the general part can be expected, the spring pressure of the spring can be set low.

  Then, according to the method of the present invention and the molding die according to the present invention, the ejector plate is connected to a general ejector plate in the projecting mechanism for projecting the microhole after molding a microhole such as a speaker grill. Since the urethane bush to be pulled is provided, it is pulled following the ascending operation of a general ejector plate, so that the spring pressure of the ejector plate in the microhole projecting mechanism can be set low. Therefore, the general ejector plate is not pushed up by the spring, so that the general protruding pin does not protrude from the mold surface into the cavity, and the molding failure such as gloss unevenness of the resin molded product accompanying with it does not occur. In addition, there is an effect that the protrusion of the protruding pin and the balance of the return can be adjusted well.

  As described above, the molding method and molding die of the resin molded product according to the present invention are such that after molding the resin molded product having fine holes into a required shape, the resin molded product is moved upward by the operation of the general protruding mechanism. This is done in two stages: the whole projecting process to project and the local projecting process to project only the fine holes such as the speaker grill. Especially for the microhole projecting mechanism, the urethane bushing is raised when the ejector plate of the general projecting mechanism is raised. Since the ejector plate in the microhole projecting mechanism can be raised synchronously via a connecting member such as a microhole, the spring pressure of the spring of the microhole projecting mechanism can be set small. Interference with the microhole protrusion mechanism can be effectively avoided, and molding defects such as gloss unevenness do not occur in the resin molded product, and the appearance looks It is possible to keep good, it is possible to reduce the protrusion and accompanying adjustment steps to the ejector pin has the effect of simplifying the adjustment work of the OTC projecting mechanism.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of a method for molding a resin molded product and a mold according to the present invention will be described in detail with reference to the accompanying drawings. Note that the gist of the present invention is as described in the scope of claims, and the contents of the embodiments described below are merely examples of the present invention.

  1 to 7 show an embodiment of the present invention. FIG. 1 is a front view showing a two-tone type door trim having a door trim lower formed by the method of the present invention, and FIG. 2 shows the structure of the two-tone type door trim. FIG. 3 is a schematic view showing the overall configuration of a molding die used in the method of the present invention, FIG. 4 is a plan view of an ejector plate in a microhole projecting mechanism in the molding die shown in FIG. FIG. 7 to FIG. 7 are explanatory views respectively showing the time when the fine hole protruding mechanism is accommodated, the initial protruding time, and the protruding end time in the method of the present invention.

  1 and 2, the structure of the door trim manufactured by the method of the present invention will be briefly described. The two-tone type automobile door trim 10 is composed of an upper and lower divided body of a door trim upper 20 and a door trim lower 30. More specifically, the door trim upper 20 is provided with an inside handle unit 11 for releasing the door lock, and an armrest 12 swelled indoors is provided at the boundary with the door trim lower 30. A switch group 13 such as a power window switch unit and a pull handle 14 are attached to the upper surface of the armrest 12. On the other hand, the door trim lower 30 is provided with a door pocket 15 that can accommodate equipment below the armrest 12, and a speaker grill 16 is provided integrally with the door trim lower 30 on the front side of the door pocket 15.

  Then, the structure of the door trim upper 20 and the door trim lower 30 will be described. As shown in FIG. 2, the door trim upper 20 is composed of a laminated structure in which a skin 22 is pasted on the surface of a resin core 21, and resin As the core material 21, polyethylene resin, polypropylene resin, polystyrene resin, polyethylene terephthalate resin, polyvinyl alcohol resin, vinyl chloride resin, polyamide resin, polyacetal resin, polycarbonate resin, ionomer resin, acrylonitrile. / Uses a thermoplastic resin such as butadiene / styrene (ABS) resin, or a composite resin material in which a filler such as talc is appropriately blended with these thermoplastic resins, and a desired curved surface shape by mold press molding or injection molding. Molded into , Skin 22 is integrally attached during molding of the resin core member 21. The skin 22 may be appropriately selected from a synthetic resin sheet, a cloth sheet such as a cloth or a non-woven fabric, and a back surface of the synthetic resin sheet or the fabric sheet is backed with a cushion layer such as polyurethane foam, polyethylene foam or polypropylene foam. The laminated sheet material can also be used. As for the joint portion between the door trim upper 20 and the door trim lower 30, a mounting boss 31 is formed on the rear surface of the joint portion of the door trim lower 30 so as to protrude toward the rear surface side. After inserting 31, the door trim upper 20 and the door trim lower 30 can be firmly joined and integrated by fixing the tip of the mounting boss 31 by ultrasonic welding caulking, heat welding caulking, or the like. The speaker grill 16 is formed by opening the micro holes 32 integrally when the door trim lower 30 is formed.

  Next, the configuration of the molding die 40 used when molding the door trim lower 30 will be described with reference to FIGS. The molding die 40 is roughly constituted by a molding upper mold 50 that can move up and down by a predetermined stroke and a molding lower mold 60 positioned below the molding upper mold 50. More specifically, the molding upper die 50 moves up and down by a predetermined stroke by driving the elevating cylinder 51, and the molding lower die 60 is supported on a spacer block 62 disposed on the base plate 61, and an injection machine (not shown). The molten resin material supplied from is supplied onto the mold surface of the molding lower mold 60 through the manifold 63 and the gate 64. Then, molten resin is injected and filled along the cavity shape formed between the upper and lower molds 50 and 60 by clamping the upper and lower molds 50 and 60 from the mold open state of the upper and lower molds 50 and 60 shown in FIG. Thus, the door trim lower 30 is formed into a required shape. With respect to the fine holes 32, the punching block 65 is fitted into the molding lower mold 60, and the fine holes 32 are formed by the punching block 65. A general projecting mechanism 70 and a microhole projecting mechanism 80 for the speaker grill 16 are set in the space between the molded lower mold 60 and the base plate 61.

  In the general projecting mechanism 70, the ejector plate 71 can be moved up and down by a predetermined stroke (around 120 mm) by driving the cylinder 72. The ejector plate 71 projects onto the upper surface of the ejector plate 71, and the angular pin 74 is supported. A slide core 75 corresponding to the shape of the undercut portion is provided at the tip of the pin 74. The protruding pin 73 and the angular pin 74 are formed by the vertical movement of the ejector plate 71, and then the door trim lower 30 is formed, and then the door trim. The lower 30 is protruded upward. Further, the door trim lower 30 is formed with a fine hole 32 like the speaker grille 16, and in particular, the portion where the fine hole 32 is formed is to prevent sticking between the molded lower mold 60 and the door trim lower 30. In addition, a large number of small-diameter pins 82 of about φ20 are set.

  In other words, as shown in FIGS. 3 and 4, as the fine hole protruding mechanism portion 80, a plurality of small-diameter pins 82 are attached to an ejector plate 81. The ejector plate 81 is formed in a disk shape and has an upper surface. A plurality of small-diameter pins 82 are erected and supported at the center of the ejector plate 81, and springs 83 are interposed on the back surface of the ejector plate 81 between the base plate 61 and the ejector plate 81. The spring is always biased in the protruding direction. Further, urethane bushes 84 are attached to the four orientations of the upper surface of the ejector plate 81, and the urethane bushes 84 are fitted into the recesses 71a of the ejector plate 71 of the general projecting mechanism unit 70. The ejector plate 81 of the fine hole projecting mechanism 80 is raised following the rise of the ejector plate 71 of the general projecting mechanism 70. Further, a guide pin 85 also serving as a stopper is attached to the base plate 61, and the ejector plate 81 of the microhole projecting mechanism portion 80 can smoothly perform a vertical stroke up and down operation of about 30 mm by the guide pin 85 serving as a stopper. become.

  FIG. 5 shows a state before both the protruding mechanism portions 70 and 80 are protruded. In this state, the urethane bush 84 of the ejector plate 81 in the protruding mechanism portion 80 for fine holes is the ejector of the general protruding mechanism portion 70. The plate 71 is accommodated in the recess 71a. In order to synchronize the ejector plate 81 with the general ejector plate 71 by the urethane bush 84, the spring pressure of the spring 83 is set to about 100 kgf, which is low. This spring 83 prevents excessive stress from being applied to the general ejector plate 71, so that there is no problem such as the protrusion of the protruding pin 73 in the general protruding mechanism portion 70, and adjustment work such as protrusion and return of the protruding pin 73 Can be simplified.

  Then, after the molding, if a projecting process for projecting the door trim lower 30 is started, as shown in FIG. 6, the general ejector plate 71 is raised by driving the cylinder 72, and the projecting pins 73, angular pins 74, etc. As a result of the rise, the entire door trim lower 30 protrudes upward. At this time, since the urethane bush 84 fitted in the recess 71a of the ejector plate 71 is lifted upward, the ejector plate 81 of the microhole projecting mechanism 80 is lifted, combined with the spring pressure of the spring 83, The fine hole 32 of the door trim lower 30 is protruded upward. As shown in FIG. 7, when the ejector plate 81 of the microhole projecting mechanism 80 rises by about 30 mm, the upper end flange 85a of the guide pin 85 having a stopper function functions as a stopper, and the ejector plate 81 and the small-diameter pin The ascent of 82 stops at that time, and only the general ejector plate 71 rises, and the general portion is protruded further upward.

  As described above, since the spring 83 and the urethane bush 84 are used in combination as the structure of the fine hole protruding mechanism portion 80 such as the speaker grill 16, the interference between the general protruding mechanism portion 70 and the fine hole protruding mechanism portion 80 is prevented. In addition to avoiding molding defects, adjustment work such as protrusion and return of the protruding pin 73 can be simplified.

  Although the present invention has been applied to the door trim lower 30 provided with the speaker grill 16, it can also be applied to a speaker grill of an integrated door trim, and can also be applied to a rear parcel shelf with an integrated speaker grill. Further, the fine holes of the resin molded product can be applied to an extractor grill.

It is a front view which shows the door trim manufactured using the method of this invention. It is the II-II sectional view taken on the line in FIG. It is a schematic diagram which shows the whole structure of the shaping die used for this invention method. It is a top view which shows the ejector plate in the protrusion mechanism part for fine holes in the shaping die shown in FIG. It is explanatory drawing which shows the state before protrusion of the protrusion mechanism part for fine holes in the shaping die shown in FIG. It is explanatory drawing which shows the state at the time of the protrusion start of the protrusion mechanism part for fine holes in the shaping die shown in FIG. It is explanatory drawing which shows the state at the time of the completion of protrusion of the protrusion mechanism part for fine holes in the shaping die shown in FIG. It is a front view which shows the structure of the door trim which has the conventional speaker grille. It is the IX-IX sectional view taken on the line in FIG. It is explanatory drawing which shows the conventional molding die. It is explanatory drawing which shows the malfunction point in the conventional molding die.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Door trim 16 Speaker grill 20 Door trim upper 30 Door trim lower 32 Micro hole 40 Molding die 50 Molding upper mold 51 Lifting cylinder 60 Molding lower mold 61 Base plate 62 Spacer block 63 Manifold 64 Gate 65 Punching block 70 General protrusion mechanism part 71 Ejector plate 72 Cylinder 73 Projection pin 74 Angular pin 75 Slide core 80 Projection mechanism for fine hole 81 Ejector plate 82 Small diameter pin 83 Spring 84 Urethane bush 85 Guide pin

Claims (2)

A method of molding a resin molded product (30) having a plurality of fine holes (32), wherein after molding upper and lower molds (50, 60) are clamped, molten resin is injected and filled into a cavity (C). After forming the resin molded product (30) having the fine holes (32) into a required shape, the fine holes (32) are protruded by a small diameter pin (82), and the general portion is a general protruding pin ( 73) In the molding method of the resin molded product (30), which employs the projecting step according to 73) and performs the projecting by different projecting strokes of the small diameter pin (82) and the projecting pin (73).
The ejector plate (81) in the projecting process of the small-diameter pin (82) is a general ejector plate that is transmitted through the spring pressure of the spring (83) and the urethane bush (84) attached to the ejector plate (81). Since the spring pressure of the spring (83) is adjusted to be small by being raised with the tensile force from (71), the general protruding mechanism (70) and the fine hole protruding mechanism (80) A method for molding a resin molded product, characterized in that interference with the resin is avoided. In the molding die (40) of the resin molded product (30) used for molding the resin molded product (30) having a plurality of fine holes (32),
The molding die (40) includes a molding upper and lower mold (50, 60) that can be mutually clamped and opened, and a general protruding mechanism (70) that projects a general part of the resin molded product (30) upward. And a fine hole protruding mechanism part (80) for locally protruding the fine hole (32) in the resin molded product (30), and the fine hole protruding mechanism part (80) moves up and down the ejector plate (81). Accordingly, the small-diameter pin (82) pushes up the fine hole (32) in the resin molded product (30) upward by a short stroke, and the ejector plate (81) is moved upward by the spring (83) set with a low spring pressure. A urethane bush that is biased by a spring and moves up the ejector plate (81) in conjunction with the lifting operation of the ejector plate (71) of the general projecting mechanism (70). 84) a molding die of a resin molded article comprising the.

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