JP2002120253A - Method and apparatus for injection molding, and mold for injection molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simply mold a strong undercut product to mold a hollow product by a die sliding method. SOLUTION: A method for injection molding comprises the steps of molding product halves 5 and 6 on mating surfaces of first to third molds 1, 2 and 3 by matching the molds in series, then retarding the central second mold 2, thereafter butting the first and third molds 1 and 3, secondarily matching the molds 1 and 3, and secondarily injecting to adhere the butted halves 5 and 6 to manufacture the product 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding method for molding a molding such as a turn signal, a side blinker, a headlamp, a door mirror, and the like when various moldings and parts to be mounted on a vehicle are taken as examples. It belongs to the technical field of molding equipment.

[0002]

2. Description of the Related Art At present, when injection molding this type of molded article, there is a method in which a pair of product halves are molded, and these product halves are butt-fixed to form a finished product. In order to mold such a material, a die slide type injection molding apparatus is generally known. Examples of such a device include, for example, JP-A-62-87315, JP-A-7-144334, and JP-A-11-16.
Japanese Patent No. 2210 is known, each of which includes a fixed mold and a movable mold, and after these molds are matched, the first half of the product is subjected to a first injection process. After molding, and then moving the movable mold to abut each of the molded product halves, the abutted halves are fixed in the second injection step.

[0003]

However, today, even in such a molded product, there is a strong demand for design in addition to diversification of products. Strong cuts (strong undercuts) have drawbacks in terms of die cutting, so simple die-to-die mold matching alone cannot keep up with demands for more complex shapes. As these molds themselves become more and more complicated, not only the molding equipment becomes larger, but also problems such as impairment of the stability of the molding are left. There are issues. Furthermore, when using the die slide method described above to form a large number of small products at once or to mold a large product, the space for the slide is required, and the mold becomes larger, There is also a problem that the device itself becomes large.

[0004]

SUMMARY OF THE INVENTION The present invention has been made for the purpose of solving these problems in view of the circumstances as described above, and the first invention is a series of three adjacent objects. A primary molding step of molding each adjacent mold, a primary injection step of injection-molding a half of a product into each of the molded dies, and A mold leaving step in which the parts are separated while remaining in the molds on both sides, and the middle mold is removed from the mold-matching area, and the remaining molds on both sides are molded to match the molded product halves. An injection molding method characterized by comprising a secondary mold matching step for joining and a secondary injection step for injecting a resin material to assemble the butted product halves. The second invention comprises a three-part mold adjacent in a series, a primary mold-matching means for molding each of the adjacent molds, and a product obtained by injecting a resin material into the mold-matched product. Primary injection means for molding the halves, mold withdrawal means for separating these molds with the product halves remaining in the molds on both sides, and withdrawing the middle mold from the mold-matching area; Secondary mold matching means for matching the remaining two-sided molds so as to match the finished product halves, and secondary injection for injecting a resin material to assemble the butted product halves. And an injection molding apparatus. Further, the third invention is a series of three adjacent dies, wherein the adjacent dies are primarily injected with a resin material in a state where they are matched with each other to form a half of a product. On the other hand, among these molds, the middle mold is a retreat mold which is withdrawn after the primary injection molding, and the outer molds on both sides are middle molds. Is a secondary injection mold that is subjected to secondary injection in order to assemble the product halves against each other in a state where they have been withdrawn. In this case, even a strongly undercut product can be efficiently molded without any problem.

[0005]

Next, embodiments of the present invention will be described. In the drawing, this is provided with first to third dies 1, 2, and 3 arranged in a series on the left and right, of which a first dies 1 is a base of a molding machine. (Guide post) The mold and the second mold 2 that move left and right with respect to G are attached to the telescopic cylinder 4 that is provided so as to move left and right with respect to the base G. The moving mold, and the third mold 3 is the base G
The mold is fixed without moving. As for the specific means of such lateral movement and vertical movement of the mold, a conventionally known technique can be employed as it is, and therefore, detailed description thereof will be omitted.
Incidentally, although the molding machine of the present embodiment has the dies arranged in a series in the left-right direction (front-rear direction), it is needless to say that the dies are arranged in a series in the up-down direction. However, the direction in which the molds are adjacent to each other is not special.

In this embodiment, a plurality of (three in this embodiment) female dies are provided on the left and right sides of the first and third dies 1 and 3, respectively, so as to face each other. 1
a and 3a are formed. On the other hand, the second mold 2 sandwiched between the left and right dies 1 and 3 includes the female dies 1a and 3a.
(FIG. 1 (A)). Then, the first and second molds 1 and 2 are moved to the left and right to perform primary mold matching, and in this state, primary injection is performed. As a result, as shown in FIG. 5 and 6 are formed. By the way, male and female types are
It is described for convenience of description, and it goes without saying that various types are formed depending on the shape and type of the product, such as a combination of a male type and a female type, a male type only, a female type only, etc. . Next, the combined molds 1 and 2 are moved in the left and right opposite directions to separate the molds 1, 2 and 3 (FIG. 1C), and then the telescopic cylinder 4 is contracted. After removing the central second mold 2 from the mold matching area (FIG. 1D), the remaining left and right molds 1 and 3 are removed.
The primary mold 1 is used for secondary mold matching (FIG. 1 (E)).
To the left and right. Thereafter, the product halves 5 and 6 are fixed by secondary injection, and the plurality of completed molded products 7 are released from the mold (FIG. 1 (F)). In addition, the retreat of the second mold from the mold matching area may be performed by relative movement with respect to the first and third molds. In addition to movement, for example,
It can also be carried out by moving the third mold.

Next, one embodiment of the mold for enabling the above-mentioned molding will be described in detail with reference to FIGS.
4, a plurality of product halves 5 (5a, 5b, 5c), 6 (6a, 6) are formed.
In the present embodiment, b and 6c) have a bottomed semi-cylindrical shape, are formed by injection from each of the injection nozzles 8 and 9, and are formed with an adhesive in a secondary injection process described later. The secondary injection material is buried in the product so that it is not exposed to the outside. To this end, each product half 5a, 5b,
5c and 6a, 6b, 6c need to communicate with each other, and a communication path for communication is required. In the present embodiment, the second mold 2 of the first and third molds 1, 3 is used. Communication grooves 1b and 3b are formed on the mold-matching surface of the above, but the filling chamber S for the secondary injection material for secondary injection and the communication path T for communicating these are also combined. Molded. That is, in this case, the male mold 2 for forming the filling chamber S is provided on the opposing surfaces of the first and third molds 1 and 3 of the second mold 2.
c and 2d are formed, and the first mold 1 of the second mold 2 is formed.
A male die 2e for forming a communication passage T that communicates with each of the filling chambers S is formed on the opposite surface of the second mold. Therefore, in the present embodiment, the communication path 1b on the first mold 1 side is formed in a deeper groove shape than the communication path 3b of the third mold 3, and the male mold 2e formed on the second mold 2 is here. The communication passages 1b are set so as to be fitted to an intermediate portion that does not reach the groove bottom, and the communication passages 1b and 3b are secured when the primary mold is matched. Then, the communication passages 1b, 3b are communicated with sprues 1c, 3c formed in the first and third molds 1, 3, and the resin material is injected from the injection nozzles 8, 9 for primary injection. The valve gate pin 10 of the injection nozzle 8 on the first mold 1 side is controlled so as to protrude to a position where it comes into contact with the male mold 2e of the second mold 2 after injecting the primary injection material (FIG. 2). . Incidentally, it is needless to say that a gate position can be provided in each cavity, and a known runner such as a hot runner or a cold runner can be appropriately employed as necessary.

Next, the molds 1, 2, and 3 are separated from each other, and the second mold 2 is moved out of the mold matching area as described above.
The remaining first and third molds 1 and 3 are matched, and the product halves 5 and 6 are compared with each other. In this butted state, as shown in FIG. 3, the above-mentioned male mold 2e becomes hollow and forms a communication path T, while male molds 2c and 2d are formed.
When the secondary injection material is injected with the valve gate pin 10 pulled into the nozzle in this state, the secondary injection material 11 is filled in each of the charging chambers S. As a result, the product halves 5, 6 are bonded and fixed to each other, and the finished product 7 is formed.

In the embodiment of the present invention configured as described above, a plurality of product halves 5, 6 are formed in the primary injection step, and then the second mold 2 is removed from the mold matching area. Thereafter, the remaining first and third molds 1 and 3 are matched to each other, and the corresponding product halves 5 and 6 are butted against each other. The secondary injection material 11 is subjected to secondary injection to form a plurality of molded products 7. As a result, even though the resin halves of the product halves 5 and 6 are different (including not only the materials themselves but also different colors and densities),
The molding can be easily performed, so that even a complicated shape or combination including a strong undercut, which is difficult to mold by the conventional die slide method, can be easily molded.

The present invention is not limited to the above-described embodiment, but can easily manufacture a strongly undercut product as in the second embodiment shown in FIGS. In the drawing, an injection nozzle, a resin passage, and a filling chamber for bonding the product halves are omitted because they are the same as in the first embodiment. In this case, the first and third molds 11 and 13 have female dies 11a and 13a and male dies 11b and 13b.
On the other hand, the female molds 11a, 1
Male molds 12a and 12b and female molds 12c and 12d are formed to correspond to 3a and male molds 11b and 13b, respectively. In the present embodiment, as shown in FIG. 5, the first, second, and third molds 11, 12, and 13 are abutted to perform a primary mold matching, and a primary injection is performed in this mold matching state to perform each primary injection. After the product halves 14 and 15 have been formed, the second mold 12 is withdrawn, and then, as shown in FIG.
The secondary products are butt-matched to each other to perform secondary injection, thereby bonding the butt portions of the product halves 14 and 15 to each other, and removing the mold to form a hollow product. Thus, the embodiment can be implemented in this manner. By employing a mold as in the second embodiment, a strong undercut product can be easily formed. 6, there is a concern that there is a lot of space on the mating surface, and there is a concern that the mold matching of the molds 11 and 13 will be unstable if this is done. As a countermeasure, for example, the mold shown in FIG. This can be solved by using a butting mode. In FIG. 7A, the second mold 12 is used for the first and third molds 1.
In the stage of the second mold butting, in which the primary mold is butted as a structure to be fitted in the first and the first mold 13, the stoppers 16, 17 which do not come into contact with each other in the first mold matching are removed. It is a thing to match,
By doing so, the first and third molds 11 and 13 can be stably butted. In this case, the stopper 16,
Reference numeral 17 may be not only a long rib shape or a frame shape but also a dotted shape. Further, as shown in FIG. 7 (B), it is a matter of course that the contact portion 18 that contacts the stoppers 16 and 17 may be formed in the second mold 12 in the primary mold matching step.

Further, as in the third embodiment shown in FIG. 8, it is possible to easily mold a boss, a groove, and a member having a convex portion 19 and a concave portion 20 such as a hole. In this case, the projections 19 and the like can be formed even if they are interrupted on the way as shown in the figure. Further, as in the fourth embodiment shown in FIG. 9, the primary injection molding is performed, the insert 21 is inserted at the stage where the second mold is removed, and then the secondary mold is processed. You can also. Furthermore, FIG.
As shown in the fifth embodiment, the insert 22 is assembled in the mold before performing the primary mold matching, and thus the primary injection, the retreat of the second mold, and the second injection are performed. Molding can also be performed by the following mold matching and secondary injection.

The injection nozzles for performing the primary injection and the secondary injection may be the same as in the first embodiment, or may be dedicated nozzles. As another example, for example, as in the sixth embodiment shown in FIG. 11, a side gate type in which an injection nozzle 23 for secondary injection is arranged on the side of the product can be used. Furthermore, as in the seventh embodiment shown in FIG. 12, the gate pin 24a of the injection nozzle 24 for secondary injection is projected to the injection path at the time of primary injection to form a flow path for secondary injection, At the time of the secondary injection, the gate pin 24a may be immersed in the primary injection flow path to perform the secondary injection. Further, in the case of performing the primary injection, the primary injection resin material may be supplied from the first mold side to the third mold side via the flow path formed in the second mold.

Furthermore, the significance of the three adjacent molds of the present invention is that if the middle mold is retracted and the molds on both sides abut each other in the secondary injection step. Well, for example, as in the eighth embodiment shown in FIG. 13, five dies 1, 2, 3, 4, and 5, counting from one end, are arranged in series, and in the primary injection step, In the secondary injection process, the second and fourth molds are simultaneously withdrawn, and the first, third, and fifth molds are abutted to form the finished product in two rows. May be formed by molding, and the unit of the mold group in this case is
The first, second, and third mold groups and the third, fourth, and fifth mold groups correspond to three adjacent molds, respectively.
Further, as this development, with respect to the molded product formed in the secondary injection step, the third mold may be further withdrawn, and the first and fifth molds may be butted to perform the third injection. This includes the case of performing such tertiary injection. Further, as in the ninth embodiment shown in FIG. 14, four dies 1, 2, 3, and 4 are arranged in a series, and in the primary injection step, the products are formed by adjacent dies. A half part is formed, and in the second injection step, the second mold is retreated, and the first and third molds are joined to each other to perform injection molding of the semi-finished products (third and fourth molds). The molded product half is set in the fourth mold and does not participate in the secondary injection molding), and in the next tertiary injection step,
The third mold may be withdrawn and the first and fourth molds may be abutted and injection molded. And in this case, not only the molding in the first, second and third mold groups,
This includes the first and fourth dies that have been butted together.

The significance of the butting of the second mold is not limited to the case where the outer circumferences are butted against each other, but a part of the butting is performed as in the tenth embodiment shown in FIG. As shown in FIG. 16, at least one of the first and third molds is aligned with each other (including butting of the ends). (Including butting), and such a thing is also included.

[Brief description of the drawings]

FIGS. 1A to 1F are schematic explanatory views showing states of an injection molding process according to a first embodiment.

FIG. 2 is an enlarged sectional view of a main part showing a mold state when primary injection is performed.

FIG. 3 is an enlarged sectional view of a main part showing a state in which a secondary mold is matched.

FIG. 4 is an enlarged sectional view of a main part showing a mold state when secondary injection is performed.

FIG. 5 is a schematic explanatory view showing a state of a primary injection molding process of the second embodiment.

FIG. 6 is a schematic explanatory view showing a state of a secondary injection molding process according to the second embodiment.

FIGS. 7 (A) and 7 (B) are schematic explanatory views showing a butting state of a mold when primary and secondary molds are respectively matched.

FIG. 8 is a schematic explanatory view showing a state of an injection molding process according to a third embodiment.

FIG. 9 is a schematic explanatory diagram showing a state of an injection molding process according to a fourth embodiment.

FIG. 10 is a schematic explanatory view showing a state of an injection molding process according to a fifth embodiment.

FIG. 11 is a schematic explanatory view showing a state of an injection molding process according to a sixth embodiment.

FIG. 12 is a schematic explanatory view showing a state of an injection molding process according to a seventh embodiment.

FIG. 13 is a schematic explanatory view showing a state of an injection molding process according to the eighth embodiment.

FIG. 14 is a schematic explanatory diagram showing a state of an injection molding process according to a ninth embodiment.

FIG. 15 is a schematic explanatory view showing a state of an injection molding process according to a tenth embodiment.

FIG. 16 is a schematic explanatory view showing a state of an injection molding process according to the eleventh embodiment.

[Explanation of symbols]

 1,11 First mold 2,12 Second mold 3,13 Third mold 5,6 Product half

Continued on the front page. (72) Inventor Shisei Ishizawa 135-10 Nishishinmachi, Ota City, Gunma Prefecture Oshima Electric Works, Ltd. (72) Inventor Masayuki Higuchi 135-10 Nishishinmachi, Ota City, Gunma Prefecture Oshima Electric Works, Ltd. F term (reference) 4F202 AH17 CA11 CB01 CB11 CC01 CK06 CK52 CK90 4F206 AH17 JA07 JB11 JC01 JQ81

Claims (3)

[Claims] 1. A primary molding process in which three adjacent dies are arranged in a series and each adjacent dies are matched, and a half part of a product is injection-molded into each of the dies. A primary injection step, a mold leaving step in which these molds are separated so that the product half remains in the molds on both sides, and a middle mold is removed from the mold matching area; And a secondary injection step of injecting a resin material to assemble the butted product halves. An injection molding method characterized by the above-mentioned. 2. A primary molding means comprising three dies which are adjacent in a series, and each of the adjacent dies is molded, and a resin material is injected into the molded products to form a product half. Primary injection means for forming a part, mold separation means for separating each of these molds with the product half remaining in the molds on both sides, and withdrawing the middle mold from the mold-matching area; Secondary mold matching means for matching the remaining two-sided molds so as to match the product halves, and a secondary injection step for injecting a resin material to assemble the butted product halves. An injection molding apparatus characterized by comprising: 3. A mold comprising three adjacent dies in a series,
Each of the adjacent molds is a primary molding mold in which a resin material is primarily injected in a state where the molds are matched to each other to form a half of a product, and a middle mold among these molds is used. Is a retreat mold that is withdrawn after the primary injection molding, and the outer two-side mold is a secondary injection mold for assembling the product halves against each other with the middle mold withdrawn. Injection molding mold, characterized in that it is a secondary injection mold to be used.