JP2008100403A - Injection molding machine and injection molding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an injection molding machine for a molding having a recess opening to the side of a core and having an installation depth of 200-1,000 mm which can release a molding from the core without breaking the recess, is excellent in productivity, and can be made at low cost. <P>SOLUTION: As regards the injection molding machine 100, a cavity is formed between a movable mold 1 and a fixed mold 2 by mold clamping, a molding material is injected/packed into the cavity, the molding material is solidified and made a molding P, and after mold opening, the molding P adherent to the movable mold 1 is ejected to the fixed mold 2 side by an ejection mechanism 3. The ejection mechanism 3 is composed of a first ejection part 4 ejecting the movable mold 1 side end part Pa of the molding P and a second ejection part 5 ejecting the movable mold 1 side end part Pe of the recess Pd of the molding P. The ejection mechanism 3 is controlled to make the first and second ejection parts 4 and 5 start ejecting the molding P simultaneously. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an injection molding apparatus and an injection molding method.

  As this type of technology, Patent Document 1 discloses an injection molding apparatus having a cavity formed by a fixed mold and a movable mold. The injection molding apparatus is provided with mold opening preventing means for preventing the mating surface of the fixed mold and the movable mold from opening during injection molding.

JP 2004-255645 A (refer to claim 1, FIG. 1)

  By the way, generally, the molding material injected into the cavity through the nozzle of the injection molding apparatus is cooled, solidified and contracted, and the core (male) is clamped and held by the stress generated during contraction. Various protruding mechanisms have been devised as devices in the mold for protruding the molded product from the core and releasing it.

  For example, (a) a projecting mechanism for projecting a molded product with ejector pins of φ6 to 15 is known. However, with this mechanism, it is difficult to cope with a so-called deep mono-shaped molded product that requires a protruding stroke of, for example, 300 to 400 [mm]. Because, firstly, in order to ensure a large protruding stroke, the ejector pin has to be long, and such an ejector pin cannot be manufactured at a low cost, and secondly, it has a deep mono shape. Therefore, the mold release resistance is also larger than that, so that if the molded product is forced to be ejected using the ejector pin, an appearance defect such as a dent will occur.

  On the other hand, for example, (b) a mechanism (so-called stripper plate protruding type) that projects the entire periphery of the core side end of the molded product is known. According to this mechanism, it is possible to avoid appearance defects such as dents when protruding.

  In addition, for example, there is an idea to reduce the above-mentioned mold release resistance by, for example, (c) performing a plating process on the mold, or (d) appropriately controlling the temperature of the mold using a temperature controller. Proposed.

  However, if the idea of (c) above is adopted, enormous plating costs will be incurred, while if the idea of (d) above is adopted, the time required for curing the injected molded product will be extended. Productivity decreases.

  The idea (b) also has the following problems depending on the shape of the molded product. Here, refer to FIG. 1 showing an example of a resin molded product.

  That is, when trying to release a molded product having a recess, which opens to the core side and has a recess depth of 200 to 1000 [mm], from the core by the above-described stripper plate protrusion type protrusion mechanism (in this figure) The image of “protruding” is indicated by a white arrow.) Due to the mold release resistance between the core and the recess, the recess remains in the core depending on the cooling time of the molded product, and the molded product is damaged. There is a risk that.

  The present invention has been made in view of such various points, and its main object is injection molding for a molded product having a recess that opens to the core side and has a recessed depth of 200 to 1000 [mm]. The present invention provides an injection molding apparatus that can release a molded product from a core without damaging the concave portion, and is excellent in productivity and inexpensive.

Means and effects for solving the problems

  The problems to be solved by the present invention are as described above. Next, means for solving the problems and the effects thereof will be described.

  According to a first aspect of the present invention, an injection molding apparatus configured as follows is provided. That is, the injection molding apparatus forms a cavity between the first mold and the second mold by mold clamping, injects and fills the molding material into the cavity, and solidifies the molding material to form a molded product. An injection molding apparatus that, after opening the mold, projects a molded product attached to the first mold to project toward the second mold by a mechanism, opens to the first mold, and is recessed. It is an injection molding apparatus for a molded product having a recess having a depth of 200 to 1000 [mm]. The protruding mechanism includes a first protruding portion that protrudes from the first mold side end portion of the molded product, and a second protruding portion that protrudes from the first mold side end portion of the concave portion of the molded product. Is done. The protruding mechanism is controlled so that the first protruding portion and the second protruding portion start to protrude the molded product simultaneously.

  According to this configuration, the molded product can be released from the first mold without damaging the recess, and an inexpensive injection molding apparatus can be obtained, and the productivity can be improved.

  In the above injection molding apparatus, the protruding stroke of the second protruding portion is set shorter than the protruding stroke of the first protruding portion. According to this configuration, it is possible to reliably avoid the recess from being damaged by the mold release resistance of the first mold with respect to the inner wall surface of the recess, which occurs immediately after the start of mold release, and the second protruding portion. The structure can be made compact.

  In the injection molding apparatus, the first protruding portion is configured as a stripper plate protruding type that protrudes the entire periphery of the first mold side end portion of the molded product. According to this configuration, it is possible to avoid appearance defects such as dents at the first mold side end of the molded product.

  According to the second aspect of the present invention, the injection molding is performed by the following method. That is, a cavity is formed between the first mold and the second mold by mold clamping, the molding material is injected and filled in the cavity, and the molding material is solidified to form a molded product. The molded product adhering to the first mold is projected to the second mold side. A molded product having a recess having an opening toward the first mold and having a recess depth of 200 to 1000 [mm] is injection molded. The first mold side end portion of the molded product and the first mold side end portion of the concave portion of the molded product begin to protrude at the same time. According to this, the molded product can be released from the first mold without damaging the recess.

  Embodiments of the present invention will be described below.

<Examples of molded products>
First, FIG. 1 shows an example of a molded product that is injection-molded by an injection molding apparatus according to an embodiment of the present invention. In FIG. 1, a front view of the molded product is displayed on the right side, and a cross-sectional view taken along the line AA is displayed on the left side. As shown in the figure, in the present embodiment, the injection molding apparatus is intended for injection molding of a molded product having a recess that opens to the core side and has a recessed depth of 200 to 1000 [mm].

<Structure of injection molding device>
Next, the structure of the injection molding apparatus according to this embodiment will be described. FIG. 2 is a side sectional view of the injection molding apparatus according to the present embodiment, and shows a state in which a molding material is injected and filled in a cavity formed in the injection molding apparatus.

  As shown in the figure, in the present embodiment, the injection molding apparatus 100 is mainly capable of approaching or separating in the direction indicated by the white arrow with respect to the fixed side mold (second mold) 2 and the fixed side mold 2. A movable side mold (first mold, core) 1 and a protruding mechanism 3 that, after opening the mold, projects the molded product P attached to the movable side mold 1 to the fixed side mold 2 side. Yes. The protruding mechanism 3 further includes a first protruding portion 4 that projects the movable-side mold 1 side end Pa of the molded product P to the fixed-side mold 2 side, and the movable side of the recessed portion Pd of the molded product P. A second projecting portion 5 projecting the mold 1 side end Pe toward the fixed-side mold 2 side, and a schematic illustration for controlling the first projecting portion 4 and the second projecting portion 5 A hydraulic control device 50 is provided.

  Further, the injection molding apparatus 100 includes a receiving plate 6 on the opposite side with the fixed-side mold 2 and the movable-side die 1 in between, and an attachment plate on the opposite side with the movable-side mold 1 and the receiving plate 6 in between. 7 is provided.

  A cavity having a predetermined shape is formed between the movable mold 1 and the fixed mold 2 at the time of mold clamping shown in FIG. A molding material is injected and filled in the cavity, and is formed into a molded product P through solidification. Therefore, the description of the shape of the cavity formed by the movable mold 1 and the fixed mold 2 will be replaced with the description of the shape of the molded product P. In the present specification, the direction from the movable side mold 1 to the fixed side mold 2 side is hereinafter referred to as a tip direction (tip side), and similarly, from the fixed side mold 2 to the movable side mold. The direction in which 1 is desired is referred to as the base end direction (base end side).

  Hereinafter, the shape of the molded product P will be described in detail with reference to FIG. Please refer to FIG. 1 as appropriate.

  As described above, in the present embodiment, the molded product P has a recess Pd that opens to the movable mold 1 side and has a recess depth of 200 to 1000 [mm].

  The molded product P has a bottomed rectangular tube shape (a U-shaped cross section) having a peripheral wall Pb and a bottom portion Pc, and a substantially central portion of the bottom portion Pc is perforated into a rectangular shape, and a rectangular hole formed by the perforation is formed. The shape extends along the contour in the proximal direction by a predetermined distance and also extends in the distal direction by a predetermined distance. The rectangular tube Pf formed by these extensions is closed by the closing wall Pg on the tip side. The concave portion Pd is composed of a square tube Pf and a blocking wall Pg, and has a U-shaped cross section through the bottom portion Pc of the molded product P.

  As shown in FIG. 1, the “recessed depth” means a distance from the end surface of the movable-side mold 1 side end Pe of the recess Pd to the inner wall surface of the closing wall Pg.

  Next, the first protruding portion 4 will be described with reference to FIG. The first protruding portion 4 protrudes the entire periphery of the movable mold 1 side end portion Pa of the molded product P toward the fixed mold 2 side (so-called stripper plate protruding type). It is formed in an annular shape so as to be fitted on the outer peripheral surface of the mold 1 in a substantially coherent manner. The first protruding portion 4 is configured to be driven by a hydraulic cylinder 8 including a hydraulic pressure supply device 8a. The movable stroke 8b of the hydraulic cylinder 8 (the protruding stroke of the first protruding portion 4) is 300 [ mm]. In the present embodiment, the hydraulic cylinder 8 is a so-called single acting single rod cylinder with a hydraulic spring.

  The second projecting portion 5 projects the movable mold 1 side end Pe of the recessed portion Pd of the molded product P to the fixed mold 2 side, and is formed in the receiving plate 6. A second hydraulic cylinder 9 and a through hole 1a fixed at one end to the second hydraulic cylinder 9 and linearly penetrating from the backing plate 6 toward the fixed mold 2 inside the movable mold 1 -It is comprised from the ejector pins 10 and 10 accommodated slidably in 1a. In this embodiment, four ejector pins 10 and 10 are provided (only two of them are shown), and the tip thereof is in the cavity in the state shown in FIG. 2 (ie, the state before mold opening). The molded product P to be formed extends in the through holes 1a and 1a so as to come into contact with the movable mold 1 side end Pe of the concave portion Pd. On the other hand, the second hydraulic cylinder 9 is provided with a hydraulic supply device 9a for supplying hydraulic oil to the second hydraulic cylinder 9 and a spring shown schematically, so that a so-called single-acting single rod cylinder with a hydraulic spring is provided. In this embodiment, the movable stroke 9b (the protruding stroke of the second protruding portion 5) is set to 50 [mm] (the set value of the movable stroke 9b is the same as that shown in the drawing). From the point of view of ease, this figure is slightly exaggerated.)

  Each of the hydraulic pressure supply device 8a and the second hydraulic pressure supply device 9a is connected to a hydraulic control device 50, which is schematically shown, so that the hydraulic control device 50 protrudes and can freely control the mechanism 3.

<Operation of injection molding device>
Next, the operation of the injection molding apparatus 100 according to the present embodiment will be described starting from the state shown in FIG. 2 (that is, the state where the molding material is injected and filled in the cavity formed in the injection molding apparatus 100). To do.

<First step: Fig. 2>
This step is a step of solidifying the molding material injected and filled in the cavity. That is, when the molded product P is made of a thermoplastic resin, the molding material is cooled and solidified by cooling the injection molding apparatus 100 using a known cooling means. Alternatively, when the molded product P is made of a thermosetting resin, the molding material is heated and cured by heating the injection molding apparatus 100 using a known heating means.

<Second step: FIG. 3>
Reference is now made to FIG. This process is a so-called mold opening process in which the movable-side mold 1 is moved in the proximal direction (indicated by a white arrow in the figure) and separated from the fixed-side mold 2. At this time, the molded product P protrudes and remains attached to the mechanism 3 side (movable side mold 1 side). Further, in the state of FIG. 3, the first protruding portion 4 and the second protruding portion 5 (tips of the ejector pins 10 and 10) are both in contact with the molded product P.

<Third step: FIG. 4>
Reference is now made to FIG. This step is a step in which the molded product P is released from the movable mold 1 in the distal direction by the movable stroke 9b of the second hydraulic cylinder 9.

  That is, the hydraulic control device 50 controls the protruding mechanism 3 so that the first protruding portion 4 and the second protruding portion 5 start to protrude the molded product P at the same time. Specifically, in the state shown in FIG. 3, the hydraulic cylinder 8 and the second hydraulic cylinder 9 start to operate simultaneously (with the steps aligned and interlocked), and each is the second hydraulic cylinder. The hydraulic pressure control device 50 controls the hydraulic pressure supply device 8a and the second hydraulic pressure supply device 9a so as to operate for nine movable strokes 9b.

<Fourth process: FIG. 5>
Reference is now made to FIG. This step is a step in which the molded product P is released from the movable mold 1 in the distal direction by the movable stroke 8b of the hydraulic cylinder 8 (corresponding to the protruding stroke of the first protruding portion 4). Since the molded product P has already been released from the movable side mold 1 in the distal direction by the movable stroke 9b of the second hydraulic cylinder 9 in the third step, in this step, the movable stroke 9b and the movable stroke 8b Further, the molded product P is released from the movable mold 1 toward the distal end by the difference.

  That is, in this step, the hydraulic control device 50 controls the second hydraulic pressure supply device 9a so as to maintain the state of the second hydraulic cylinder 9 shown in FIG. 4, and the hydraulic cylinder 8 is compared with the state of FIG. Then, the hydraulic pressure supply device 8a is controlled so as to be extended by the movable stroke 8b cumulatively. As a result, a gap G is formed between the tip of the ejector pins 10 and 10 and the movable die 1 side end Pe of the recess Pd.

<Fifth process>
This step is a step of collecting the molded product P from the injection molding apparatus 100. In other words, the mold release resistance of the movable mold 1 with respect to the molded product P is almost completely eliminated (disappeared) by the above first to fourth steps, and is known in the state shown in FIG. The molded product P is recovered by the recovery means. Then, the collected molded product P is shipped through a predetermined process such as a deburring process.

<Sixth step>
Then, the movable mold 1 is brought close to the fixed mold 2 and clamped, and the first protruding portion 4 and the second protruding portion 5 are returned to the state shown in FIG. 2, and the molding material is injected again. A cavity formed in the molding apparatus 100 is injected and filled.

  As described above, in the present embodiment, the injection molding apparatus 100 is configured as follows. That is, the injection molding apparatus 100 forms a cavity between the movable side mold 1 (first mold) and the fixed side mold 2 (second mold) by clamping, and the molding material is placed in the cavity. Injecting and filling, solidifying this molding material to form a molded product P, and after opening the mold, the molded product P adhering to the movable side mold 1 protrudes and protrudes to the fixed side mold 2 side by the mechanism 3 An injection molding apparatus 100 for a molded product P having a recess Pd that opens to the movable mold 1 side and has a recess depth of 200 to 1000 [mm]. The protruding mechanism 3 includes a first protruding portion 4 protruding from the movable-side mold 1 side end Pa of the molded product P, and a movable-side mold 1 side end Pe of the concave portion Pd of the molded product P. And a second protruding portion 5 that protrudes. The protruding mechanism 3 is controlled such that the first protruding portion 4 and the second protruding portion 5 start to protrude the molded product P at the same time.

  According to this configuration, the molded product P can be released from the movable mold 1 without damaging the concave portion Pd, and the inexpensive injection molding apparatus 100 can be obtained, and the productivity can be improved.

  In the injection molding apparatus 100, the protruding stroke of the second protruding portion 5 (movable stroke 9b of the second hydraulic cylinder 9) is larger than the protruding stroke of the first protruding portion 4 (movable stroke 8b of the hydraulic cylinder 8). It is set short. According to this configuration, it is ensured that the concave portion Pd is damaged by the mold release resistance of the movable mold 1 with respect to the inner wall surface of the concave portion Pd that occurs immediately after the start of mold release (that is, at the initial stage of release). While avoiding, the structure of the said 2nd protrusion part 5 can be made compact.

  In the injection molding apparatus 100, the first protruding portion 4 is configured as a stripper plate protruding type that protrudes the entire periphery of the movable side mold 1 side end portion Pa of the molded product P. According to this configuration, it is possible to avoid appearance defects such as dents at the end portion Pa on the movable mold 1 side of the molded product P.

  According to the second aspect of the present invention, the injection molding is performed by the following method. That is, a cavity is formed between the movable side mold 1 and the fixed side mold 2 by clamping, the molding material is injected and filled in the cavity, and the molding material is solidified to form a molded product P. After opening the mold, the molded product P adhering to the movable mold 1 is protruded to the fixed mold 2 side. A molded product P having an indented portion Pd that is open to the movable mold 1 side and has a recessed depth of 200 to 1000 [mm] is injection-molded. The movable mold 1 side end portion Pa of the molded product P and the movable side mold 1 side end Pe of the concave portion Pd of the molded product P begin to protrude at the same time. According to this, the molded product P can be released from the movable mold 1 without damaging the concave portion Pd.

  Although the preferred embodiments of the present invention have been described above, the above embodiments can be implemented with the following modifications.

In the above embodiment, the first mold is the movable mold 1 and the second mold is the fixed mold 2. However, the present invention is not limited to this. For example, the second mold is the movable mold 1 and the first mold. The mold may be the fixed mold 2.

The molded product P that is injection molded by the injection molding apparatus 100 may be made of a thermoplastic resin or a thermosetting resin.

In addition, although both the hydraulic cylinder 8 and the second hydraulic cylinder 9 are so-called single acting single rod cylinders with a hydraulic spring, the invention is not limited thereto, and may be, for example, a pneumatic return single rod cylinder. Of course, the first protrusion 4 and the second protrusion 5 may be configured to be driven by an electric actuator.

In addition, the movable mold 1 and the fixed mold 2 are integrally formed, but instead of this, a configuration including one or a plurality of nestings may be adopted.

Also, a known return pin may be employed as means for returning the first protruding portion 4 and the second protruding portion 5 from the state shown in FIG. 5 to the state shown in FIG.

In addition, the protruding stroke of the first protruding portion 4 is 300 [mm] in the above embodiment, but is not limited to this, for example, within a range of 150 to 300 [mm] (250 [mm], etc. ) May be appropriately selected. When the extending length of the peripheral wall Pb of the molded product P is set to 800 [mm], it is reasonable that the protruding stroke is about 300 to 400 [mm].

In addition, the protruding stroke of the second protruding portion 5 is 50 [mm] in the above embodiment, but is not limited thereto, and can be appropriately selected, for example, within a range of 20 to 50 [mm]. It is only necessary to secure a protruding stroke that can eliminate the mold release resistance of the movable mold 1 with respect to the recess Pd of the product P.

The present invention also exhibits extremely beneficial effects as in the above embodiment when applied to an injection molding apparatus for injection molding a molded product P as shown in FIGS.

  The molded product P1 shown in FIG. 6 differs from the molded product P according to the above embodiment in the following points. That is, in the molded product P according to the above embodiment, the concave portion Pd is formed so as to penetrate the bottom portion Pc, whereas in the molded product P1 shown in this figure, the concave portion Pd has a square tube extending from the bottom portion Pc to the core side. It is formed by existing.

  The molded product P2 shown in FIG. 7 differs from the molded product P according to the above-described embodiment in the following points. That is, in the molded product P2 shown in this drawing, the recess Pd is formed by extending the square tube only from the bottom Pc to the side opposite to the core side.

  The molded product P3 shown in FIG. 8 is different from the molded product P according to the above embodiment in the following points. That is, the molded product P3 shown in the figure is formed in a bottomed cylindrical shape, and similarly, the concave portion Pd is formed by extending the cylinder from the bottom portion Pc.

The figure which shows an example of the molded article injection-molded by the injection molding apparatus which concerns on one Embodiment of this invention Side surface sectional drawing of the injection molding apparatus which concerns on one Embodiment of this invention. It is a figure similar to FIG. 2, Comprising: The figure showing the 2nd process of injection molding It is a figure similar to FIG. 2, Comprising: The figure showing the 3rd process of injection molding It is a figure similar to FIG. 2, Comprising: The figure showing the 4th process of injection molding The figure which shows an example of the molded article injection-molded by the injection molding apparatus which concerns on other embodiment of this invention. The figure which shows an example of the molded article injection-molded by the injection molding apparatus which concerns on other embodiment of this invention. The figure which shows an example of the molded article injection-molded by the injection molding apparatus which concerns on other embodiment of this invention.

Explanation of symbols

1 Movable mold
2 Fixed mold
3 Protruding mechanism
4 First overhang
5 Second overhang
100 injection molding equipment
P Molded product
Pa (molded product P) movable side mold 1 side end
Pb wall
Pc bottom
Pd recess
Pe (indented Pd) Movable mold 1 side end
Pf square tube
Pg blockage wall

Claims (4)

A cavity is formed between the first mold and the second mold by mold clamping, and a molding material is injected and filled in the cavity, and the molding material is solidified to form a molded product. An injection molding apparatus in which a molded product adhered to a first mold is projected to the second mold side by a protruding mechanism, and is opened to the first mold side, and a recessed depth is 200 to 1000 [ mm], in an injection molding apparatus for a molded article having a recess,
The protruding mechanism is
A first protrusion protruding from the first mold side end of the molded product;
A second projecting portion that projects the first mold side end of the concave portion of the molded article;
Consists of
The injection mechanism is controlled so that the first protruding portion and the second protruding portion start to protrude the molded product at the same time. The protruding stroke of the second protruding portion is set shorter than the protruding stroke of the first protruding portion.
The injection molding apparatus according to claim 1. The first protruding portion is configured as a stripper plate protruding type that protrudes the entire periphery of the first mold side end portion of the molded product.
The injection molding apparatus according to claim 1 or 2, A cavity is formed between the first mold and the second mold by mold clamping, and a molding material is injected and filled in the cavity, and the molding material is solidified to form a molded product. An injection molding method for projecting a molded product attached to a first mold to the second mold side, the recess being open to the first mold side and having a recessed depth of 200 to 1000 [mm] In an injection molding method for injection molding a molded article having
The first mold side end of the molded article;
The first mold side end of the recess of the molded article;
Injection molding method characterized by starting to protrude at the same time

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