JP5686695B2 - Injection molding method and apparatus - Google Patents

Description

  The present invention relates to an injection molding method and apparatus for obtaining a molded product by filling a cavity formed in a mold with a molding material.

  The present applicant fills a cavity formed in a mold with a molding material such as molten resin, and then cools and cures the molding material to perform injection molding to obtain a molded product and an injection molding method. (Refer to Patent Document 1).

  In this injection molding, the resin is melted by an injection machine, and the obtained molten resin is injected from the injection machine, and hot runners formed in a plurality of molds are distributed. The molding material is further introduced into the product part via a gate or the like formed in the mold. As a result, the molten resin injected into the cavity flows along the shape of the cavity, and further, as the heat is taken away, the molten resin is cooled and cured to become a molded product.

JP 2004-223858 A

  The present invention has been made in consideration of the above-described problems, and an object of the present invention is to provide an injection molding method and apparatus capable of reducing manufacturing cost and improving productivity.

To achieve the above object, the present invention provides an injection molding method for obtaining a molded product by filling a cavity formed in a mold with a molding material.
The first mold in which the first molding part is formed in advance in the first cavity and the second mold having the second cavity are clamped, and the first mold passage and the second mold Injecting the molding material into the second cavity through a gate to mold a second molding part;
Simultaneously injecting the molding material into the second cavity, and injecting the molding material into the sub-cavity of the first mold through the gate to form a lock portion;
The first mold and the second mold are opened, and a gate portion formed by the gate is separated from the second mold through a lock portion engaged with the first mold, and the second mold Separating the gate part joined to the molded part and taking it out of the gate;
It is characterized by having.

  According to the present invention, when the second molded part constituting the molded product is molded in the second cavity of the second mold, the molding material is filled into the subcavity of the first mold through the gate of the second mold. Thereafter, when the mold is opened between the first mold and the second mold, the gate portion is held with respect to the first mold under the engaging action of the lock portion formed in the subcavity, and integrally It can be detached from the second mold. The end of the gate part is cut off from the second molding part and taken out from the gate.

  Therefore, when the mold opening is performed, the hardened portion of the molding material does not remain in the second mold gate, and the mold opening between the first mold and the second mold is performed easily and reliably. Since it can be taken out, the man-hour for removing the gate part from the second mold can be reduced compared with the injection molding method according to the prior art in which the gate part and the like are removed in a separate process from the mold opening. it can.

  Moreover, since it is not necessary to divide the second mold into a plurality of parts in advance for the purpose of removing the gate portion from the second mold after injection molding, the capital investment required for the injection molding apparatus including the second mold is eliminated. It is possible to reduce.

  Furthermore, the second molded part may be joined to the first molded part to form a molded product.

Furthermore, the first molded part and the second molded part may be formed of different materials and / or colors .

Furthermore, the present invention provides an injection molding apparatus for obtaining a molded product by filling a cavity formed in a mold with a molding material.
A first type having a first Cavity I,
The approaching or away freely provided to the first type, a gate communicating with the second cavity facing the first cavity when the mold clamping of the first type, and said a through passage second cavity A second mold having
A subcavity formed in the first mold and communicating with the gate when the mold is clamped with the second mold;
With
The gate is formed in a tapered shape in which a passage diameter decreases from one end side connected to the passage toward the other end side connected to the second cavity.

  The gate may be formed in a circular arc shape that is curved in a direction away from the first mold.

  Further, the subcavity may be formed in a tapered shape with a diameter gradually increasing in a direction away from the second mold.

  According to the present invention, the following effects can be obtained.

  That is, when the mold opening between the first mold and the second mold is performed, the cured gate portion of the molding material does not remain in the gate of the second mold, and the mold opening is simple and easy. Since it can be reliably removed, the number of steps for removing the gate portion from the second mold can be reduced compared to the injection molding method according to the prior art in which the gate portion and the like are removed in a separate process from the mold opening. As a result, productivity can be improved. Moreover, since it is not necessary to divide the second mold into a plurality of parts in advance for the purpose of removing the gate portion from the second mold after injection molding, the capital investment required for the injection molding apparatus including the second mold is eliminated. Accordingly, the manufacturing cost can be reduced.

It is a principal part schematic longitudinal cross-sectional view of the injection molding apparatus which concerns on embodiment of this invention. It is an expanded sectional view which shows the 2nd cavity and gate vicinity in FIG. It is explanatory sectional drawing which shows the state in which the injection molding of the 2nd cavity is performed in the injection molding apparatus of FIG. FIG. 4 is an enlarged cross-sectional view illustrating the vicinity of a second cavity and a gate in FIG. 3. FIG. 5 is an enlarged cross-sectional view showing a state in which the fixed mold and the movable mold in FIG. 4 have begun to open. FIG. 6 is an enlarged cross-sectional view showing a state in which the gate forming portion of FIG. 5 is taken out from the gate. FIG. 4 is an explanatory cross-sectional view showing a state where a fixed mold and a movable mold are completely opened in the injection molding apparatus of FIG. 3 and a molded product is taken out.

  An injection molding method according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings by giving preferred embodiments in relation to an injection molding apparatus that performs the injection molding method. FIG. 1 is a schematic vertical sectional view of an essential part of an injection molding apparatus 10 according to the present embodiment.

  As shown in FIGS. 1 to 7, the injection molding apparatus 10 includes a fixed mold (first mold) 12 and a movable mold that approaches or separates from the fixed mold 12 under the action of a displacement mechanism (not shown). Second type) 14.

  The fixed mold 12 includes a runner (passage) 20 to which a molding material (for example, molten resin or molten rubber) is supplied from an injection nozzle 18 of an injection machine 16, and a first molding part (first molding part) of a molded product 22. And a first cavity (first cavity) 26 for molding 24.

  The runner 20 includes, for example, a first passage 32 extending from the opening 28 opened on the end surface of the fixed mold 12 toward the first contact surface 30 (in the direction of arrow A) that contacts the movable mold 14, and the first passage 32. A second passage 34 that branches substantially orthogonally to the first passage 32, and bends at substantially right angles from both ends of the second passage 34, and extends toward the first contact surface 30 (in the direction of arrow A). And a third passage 36. The end of the third passage 36 constituting the runner 20 is open to the first contact surface 30.

  A pair of first cavities 26 are recessed with a predetermined depth with respect to the first abutment surface 30 of the fixed mold 12, are formed in a substantially rectangular cross section, and are provided at a predetermined interval along the width direction of the fixed mold 12. It is done.

  In addition, sub-cavities 38 that are recessed with respect to the first contact surface 30 are formed between the third passage 36 of the runner 20 and the first cavity 26. The subcavity 38 is formed in a tapered shape with a diameter gradually increasing in a direction away from the first abutting surface 30 (arrow B direction), and is formed with a small volume with respect to the first cavity 26. .

  The movable die 14 is opened to a second abutment surface 40 that abuts the fixed die 12, and a pair of second cavities (a pair of second cavities formed so as to face the first cavity 26 when clamping with the fixed die 12). A second cavity) 42 and a pair of gates 44 communicating with the second cavity 42.

  The second cavity 42 is formed so as to be substantially symmetrical with the first cavity 26 with the first and second contact surfaces 30 and 40 as a boundary in a state where the fixed mold 12 and the movable mold 14 are clamped. . That is, the second cavity 42 is formed to have a substantially rectangular cross section like the first cavity 26.

  As shown in FIG. 2, the gate 44 faces the third passage 36 of the runner 20 in a state where the fixed mold 12 and the movable mold 14 are clamped, and the introduction portion 46 to which the molding material is supplied through the runner 20. And a communication portion 48 that connects the end portion of the introduction portion 46 and the second cavity 42.

  The introduction portion 46 is provided along the second contact surface 40, and one end portion thereof is a position facing the third passage 36 of the fixed mold 12, and the other end portion is a position facing the subcavity 38 of the fixed mold 12. Formed. In other words, the introduction portion 46 is formed on the second contact surface 40 so as to be spaced apart from the second cavity 42 by a predetermined distance on a substantially straight line.

  Then, the molding material supplied to the runner 20 of the fixed mold 12 is supplied to the communication portion 48 through the introduction portion 46 and simultaneously supplied to the subcavity 38 and filled.

  The communication portion 48 is connected at the other end of the introduction portion 46 so as to be separated from the second contact surface 40, and is curved in a circular arc shape so as to connect the introduction portion 46 and the second cavity 42. Formed. Specifically, the communication portion 48 is formed to be curved in a circular arc shape in a direction away from the second contact surface 40.

  The communication portion 48 is, for example, a passage formed in a circular cross section, and is formed in a tapered shape so that the passage diameter gradually decreases from the introduction portion 46 side toward the second cavity 42 side. That is, the communication portion 48 has the largest passage diameter D1 of the one end portion 48a connected to the introduction portion 46, and conversely, the passage diameter D2 of the other end portion 48b connected to the second cavity 42 becomes the smallest. It is formed (D1> D2).

  Further, the other end 48 b of the communication portion 48 is connected to the bottom surface of the second cavity 42 formed substantially parallel to the second contact surface 40.

  The injection molding apparatus 10 according to the embodiment of the present invention is basically configured as described above. Next, its operation and effects will be described. In the following description, as shown in FIGS. 1 and 2, in the injection molding apparatus 10, the molding material is injected into the first cavity 26 by the fixed mold 12 and another movable mold (not shown). A case will be described in which secondary molding is performed from a state in which the first molded portion 24 is already molded and the plate 50 is joined so as to straddle the pair of first molded portions 24.

  When injection molding is performed from the state shown in FIG. 1 in which the first molding part 24 is molded with the fixed mold 12 as described above, the movable mold 14 is moved toward the fixed mold 12 under the action of a displacement mechanism (not shown). Then, mold clamping is performed with the first contact surface 30 and the second contact surface 40 in contact with each other (see FIG. 2).

  Next, as shown in FIGS. 3 and 4, the molding material is injected from the injection nozzle 18 of the injection machine 16 inserted into the opening 28 of the fixed mold 12. The injected molding material flows from the opening 28 to the runner 20 and is supplied to the gate 44 of the movable mold 14 through the second and third passages 34 and 36 that are bifurcated. Then, the molding material flows from one end portion to the other end portion in the introduction portion 46 of the gate 44, and a part of the molding material is filled in the subcavity 38 of the fixed mold 12, and at the same time, the remaining molding material is communicated with the communication portion 48. Then, the second cavity 42 is filled.

  Then, in a state where the molding material is completely filled in the second cavity 42, the molding material is cooled and cured, whereby the second molding part (second molding part) 52 is molded in the second cavity 42. . The second molding portion 52 is joined to the first molding portion 24 that is preliminarily molded by the fixed mold 12 and integrally covers the plate 50 in the vicinity of the boundary with the first molding portion 24. Thereby, the molded product 22 in which the first molded portion 24 and the second molded portion 52 are joined with the plate 50 as the center is obtained.

  On the other hand, the molding material is cured in the runner 20 to become the runner molding portion 54 and is cured in the gate 44 to become the gate molding portion 56. The gate forming portion 56 includes a base portion 58 having a rectangular cross section hardened by the introduction portion 46, a lock portion 60 hardened by the subcavity 38, and a gate portion 62 hardened by the communication portion 48 (see FIG. 4). . The lock portion 60 and the gate portion 62 are joined to the other end portion of the base portion 58.

  Next, the movable mold 14 is moved away from the fixed mold 12 under the action of a displacement mechanism (not shown) to open the mold. At this time, the molded product 22 composed of the first and second molding parts 24 and 52 remains in the second cavity 42, and as the movable mold 14 moves away from the fixed mold 12, the gate molding part 56 Since the lock portion 60 is held while being engaged with the subcavity 38, the base portion 58 and the gate portion 62 of the gate molding portion 56 are pulled in a direction away from the movable mold 14 (arrow B direction). The

  Accordingly, as shown in FIG. 5, the base portion 58 constituting the gate forming portion 56 is detached from the introduction portion 46, and the gate portion 62 moves to the fixed mold 12 side (arrow B direction) together with the base portion 58. By being pulled, the distal end portion 62a of the gate portion 62 formed in a tapered shape and joined to the second molding portion 52 is cut by the tensile force, and then, along the communication portion 48, toward the introduction portion 46 side. Moving. At this time, since the gate portion 62 is formed of elastic resin, rubber, or the like, the gate portion 62 moves toward the introduction portion 46 while being elastically deformed inside the communication portion 48.

  Then, by further separating the fixed mold 12 and the movable mold 14, as shown in FIG. 6, the gate part 62 separated from the second molding part 52 is completely detached from the communication part 48, and the gate The molding portion 56 is detached from the movable die 14 together with the fixed die 12.

  Finally, as shown in FIG. 7, the molded product 22 is pushed out by, for example, a knockout pin (not shown) and taken out from the movable mold 14, so that both ends of the plate 50 are a pair of first and second moldings. The molded product 22 covered with the parts 24 and 52 is obtained.

  As described above, in the present embodiment, the sub-cavity 38 is provided in the fixed mold 12 constituting the injection molding apparatus 10, and the molding material supplied to the gate portion 62 and the second cavity 42 of the movable mold 14 is simultaneously added to the molding material. In addition to being supplied to the sub-cavity 38, the communication portion 48 that constitutes the gate portion 62 and is connected to the second cavity 42 is formed so as to gradually taper toward the second cavity 42 side. .

  Thus, after the second molding part 52 constituting the molded product 22 is molded in the second cavity 42, the lock part 60 molded in the subcavity 38 is opened when the stationary mold 12 and the movable mold 14 are opened. The gate forming part 56 is held with respect to the fixed mold 12 under the engaging action of the above, and at the same time the gate part 62 formed in the communication part 48 is formed in a tapered shape. The distal end portion 62a is separated from the second molding portion 52 by a tensile force and is taken out from the movable mold 14.

  As a result, the gate molding portion 56 having the cured molding material does not remain in the gate portion 62 of the movable mold 14, and the fixed mold 12 and the movable mold 14 are opened easily and reliably. Therefore, it is possible to reduce the man-hours for removing the gate forming portion 56 from the movable mold 14 as compared with the injection molding method according to the prior art in which the gate forming portion and the like are removed in a separate process from the mold opening. it can. Specifically, the step of taking out the gate forming portion 56 from the communicating portion 48 of the movable mold 14 and the post-processing for separating the end portion of the gate forming portion 56 and the second forming portion 52 can be eliminated. That is, it is possible to improve productivity when the molded product 22 is molded in the injection molding apparatus 10.

  Further, since it is not necessary to divide the movable mold into a plurality of parts in advance for the purpose of removing the gate molding portion 56 from the movable mold 14 after injection molding, the capital investment required for the injection molding apparatus 10 including the movable mold is eliminated. It is possible to reduce. As a result, it is possible to reduce the manufacturing cost in the injection molding apparatus 10.

  Furthermore, since the communication portion 48 is formed in a circular arc shape, when the gate portion 62 formed by the communication portion 48 is pulled, it can be suitably moved along the communication portion 48. The gate part 62 is not caught in the communication part 48 and can be taken out smoothly.

  Furthermore, since the lock portion 60 is formed in a tapered shape having an enlarged diameter in the direction away from the first contact surface 30 of the fixed mold 12 (arrow B direction) and is engaged with the subcavity 38, Even when a tensile force is applied to the gate forming part 56 toward the movable mold 14 (in the direction of arrow A) when the fixed mold 12 is moved away from the movable mold 14, the gate forming part 56 remains in the fixed mold 12. It can be securely held against the fixed mold 12 without being detached from the movable mold 14 and can be reliably detached from the movable mold 14.

  Further, for example, the molded product 22 can be obtained by molding the first molding part 24 and the second molding part 52 with different materials or colors.

  Note that the injection molding method and the apparatus according to the present invention are not limited to the above-described embodiments, and various configurations can be adopted without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 10 ... Injection molding apparatus 12 ... Fixed mold 14 ... Movable type 16 ... Injection machine 18 ... Injection nozzle 20 ... Runner 22 ... Molded product 24 ... 1st molding part 26 ... 1st cavity 38 ... Subcavity 42 ... 2nd cavity 44 ... Gate 46 ... Introducing section 48 ... Communication section 52 ... Second molding section 56 ... Gate molding section 58 ... Base section 60 ... Lock section 62 ... Gate section

Claims (6)

In an injection molding method for obtaining a molded product by filling a molding material into a cavity formed in a mold,
The first mold in which the first molding part is formed in advance in the first cavity and the second mold having the second cavity are clamped, and the first mold passage and the second mold Injecting the molding material into the second cavity through a gate to mold a second molding part;
Simultaneously injecting the molding material into the second cavity, and injecting the molding material into the sub-cavity of the first mold through the gate to form a lock portion;
The first mold and the second mold are opened, and a gate portion formed by the gate is separated from the second mold through a lock portion engaged with the first mold, and the second mold Separating the gate part joined to the molded part and taking it out of the gate;
An injection molding method characterized by comprising: The injection molding method according to claim 1, wherein
The injection molding method, wherein the second molding part is joined to the first molding part to form a molded product. The injection molding method according to claim 1 or 2,
Injection molding process, characterized in that pre-Symbol a first mold portion, said second mold portion are formed of different materials and / or colors. In an injection molding apparatus for obtaining a molded product by filling a cavity formed in a mold with a molding material,
A first type having a first Cavity I,
The approaching or away freely provided to the first type, a gate communicating with the second cavity facing the first cavity when the mold clamping of the first type, and said a through passage second cavity A second mold having
A subcavity formed in the first mold and communicating with the gate when the mold is clamped with the second mold;
With
The injection molding apparatus, wherein the gate is formed in a tapered shape with a passage diameter decreasing from one end side connected to the passage toward the other end side connected to the second cavity. The injection molding apparatus according to claim 4, wherein
The injection molding apparatus according to claim 1, wherein the gate is formed in a circular arc shape that is curved in a direction away from the first mold. The injection molding apparatus according to claim 4 or 5,
The injection molding apparatus according to claim 1, wherein the subcavity is formed in a tapered shape with a diameter gradually increasing in a direction away from the second mold.

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