JP3702747B2 - Injection molding method and injection mold - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a method for molding an injection-molded article whose surface is covered with a molded article and an injection mold thereof.
[0002]
[Prior art]
As a method of obtaining an injection molded product colored in a color different from that of the molding material, a method of integrally molding a pre-colored coating film and an injection molded product is known. In this method, the coated film is set in an injection mold, and after the mold is clamped, the film is fixed or welded to the product surface by filling a mold resin with a molten resin as a molding material. The injection molded product and the film are integrally formed.
[0003]
When molding a large product using this method, it is difficult to fill the resin from one gate to the end of the product, so it is generally performed using a multi-point gate. It is known to employ a direct gate as a method. FIG. 11 shows the position of the large gate product and the direct gate that are molded by a multi-point direct gate. In this case, the molten resin coming out of the direct gate 12 hits the back surface of the coating film (not shown), but since the molten resin flows at a high temperature and high pressure, the previously colored coating film is stretched and has a color compared to other parts. There may be a problem in quality of thinning. As a method for solving this problem, it is conceivable to perform filling from a plurality of parts using the side gate 4 as shown in FIG.
[0004]
[Problems to be solved by the invention]
When the side gate is used, as shown in FIG. 12, the end surface of the covering film 6 is applied to the runner 5, and when the mold is closed, the covering film 6 is sandwiched between the molds, and the covering film 6 is stretched and loosened. . The process in which the covering film 6 is stretched will be specifically described with reference to FIGS. 13 and 14. FIG. 13 is a cross-sectional view taken along the line gg of FIG. 12, and FIG. 14 is a coating in the process from mold opening (FIG. 14 (a)) to mold clamping (FIG. 14 (c)) of the runner forming portion of the mold shown in FIG. The state of a film is shown. In the mold open state shown in FIG. 14A, the covering film 6 is set in the mold, and there is no space between the film and the mold. However, when the mold is tightened, the covering film 6 is sandwiched and crushed by the upper and lower mold dividing surfaces of the runner 5 shown in FIG. 14C, so that the crushed covering film 6 is extruded in the Z direction. The extruded coating film 6 is in a relaxed state in the runner 5, and a space K is formed in the mold 2 and the coating film 6. In this case, the molten resin that has flowed through the runner 5 flows into the space K, and the molten resin flows into both surfaces of the covering film 6, so that the covering film is not integrally formed on the surface of the product.
[0005]
Here, it is conceivable that the covering film 6 covers all of the runner 5 as well as the product portion and the side gate portion. However, a large amount of the covering film is used in a portion not used as a product, and the cost increases. Occurs. Therefore, there is a demand for molding a product using the minimum necessary film without causing the above-mentioned problems.
[0006]
[Means for Solving the Problems]
Since also the present invention has been devised in order to effectively solve the above problems, according to claim 1 invention, the film will cover the one surface of the product on the molding completion stage , Set on the mold surface of one mold forming the product space, and at the time of subsequent clamping, covered with the film up to the gate and part of the runner formed on the other mold so as to be continuous therewith above, a injection molding method for integral molding of the film and products by filling the molding material into the product portion space through the gate from the runner, the film and one of the type the film is to be set A concave shape is formed in advance in a part of the mold surface opposite to the runner, and when the film is set on the mold surface of the one mold, the mold is clamped after the film is set. The groove width of the runner consecutive bets is matched the recess shape to each other so as to extend over the film, and characterized in that by clamping in this state to integrally form a film and product only is brought into close contact with the concave shape to each other To do.
The invention according to claim 2 is characterized in that the edge length of the cross section constituting the concave shape formed in the film is shorter than the edge length of the cross section constituting the concave shape formed on the mold surface of one mold. to.
Serial mounting of the invention in claim 3 is characterized in that the recess shape formed on the mold surface of one mold is provided with a deeper level difference than the thickness of the film.
[0007]
Serial mounting of the invention in claim 4, the film will cover the one surface of the product on the molding completion stage set in one die mold surface of which forms a product portion space, gates and the subsequent clamping time A film and a product are formed by filling the molding material into the product space from the runner through a gate after covering the portion facing the part of the runner formed in the other mold so as to be continuous with the film. the a injection molding method for integral molding, the film while preformed recess shape on the end portion facing the runner of the mold surface of one of the mold that is to be set, the other type When a film fixing pin is provided in a portion of the mold surface facing the concave shape, and the film is clamped after setting the film on the mold surface of the one mold, the groove width of the runner continuous with the gate is set. Beam is brought into close contact against the film at the runner opposite to the recess shape with respect to the film fixing pin while crossing, characterized by integrally molding the film and the product in that state.
[0009]
Serial mounting of the invention in claim 5, the film will cover the one surface of the product on the molding completion stage set in one die mold surface of which forms a product portion space, gates and the subsequent clamping time A film and a product are formed by filling the molding material into the product space from the runner through a gate after covering the portion facing the part of the runner formed in the other mold so as to be continuous with the film. And forming a concave shape at the end of the part facing the runner out of the mold surface of one mold on which the film is to be set,
A film fixing pin is provided in a part of the mold surface of the other mold that faces the concave shape, and the film is pressed and adhered to the concave shape facing the runner at the time of mold clamping. It is characterized by that.
[0010]
【The invention's effect】
The present invention has the following effects for each claim.
[0011]
According to the serial mounting of the invention in claim 1, since it becomes the film at the die matching surface of the mold runner near the time of mold clamping is that it stretched collapsed film has a concave shape, the type of It coincides with the concave shape and extends in the direction along it. Therefore, there is no space between the film and the mold or the space is reduced. Thereby, the resin does not wrap around between the film and the mold, and the film can be integrally formed on the surface of the molded product, and an injection molded product coated with a film having a good appearance can be obtained.
[0012]
According to the serial mounting of the invention in claim 2, than shorter than the cross section of the edge length of the edge length of the section constituting the concave shape provided in the film constitutes a concave shape provided in the mold, after the mold clamping Luke space is not between the film and the mold, also properly is further reduced. Therefore, the film can be surely integrally formed on the surface of the molded product, and an injection molded product coated with a film having a good appearance can be obtained.
[0013]
According to invention of Claim 3, since the level | step difference is provided in the recessed shape formed in the type | mold surface of one type | mold which sets a film, when a molding material contacts with a film, a film is flown by resin which flowed in It will be pressed against the mold. Therefore, it does not wrap around between the film and the mold, and the film can be surely integrally formed on the surface of the molded product.
[0014]
According to the serial mounting of the invention in claim 4, 5, since the film extending collapsed by die matching surface when the mold clamping is pressed against the mold by the film fixing pins, space is eliminated between the film and the mold. Therefore, the resin does not wrap around between the film and the mold, and the film can be reliably integrally formed on the front side of the molded product, and an injection molded product coated with a film having a good appearance can be obtained.
[0015]
【Example】
Example 1
1 to 6 show a first embodiment of the present invention.
[0016]
FIG. 6 shows the mold with the film set. 1 is a side gate portion of the injection molding die of the present invention and is an enlarged view of a portion d in FIG. 6. FIG. 2 is a cross-sectional view taken along the line aa in FIG. FIG. 3 is a cross-sectional view taken along the line bb in FIG. 1 and shows the state of the film before clamping, and FIG. 4 is a cross-sectional view taken along the line bb in FIG. 1 and shows the state of the film after mold clamping. ing.
[0017]
Near the support Idogeto 4 of the mold surface of the mold 2 in this embodiment is provided with a bicycloalkenyl over de shape 8 as concave shape at a position facing the runner 5 of the mold 1 as shown in FIGS. The size of the bead shape 8 is larger than that of the runner 5 as shown in FIG. 3, but may be smaller .
[0018]
Also, the site where the coating film 6 of the mold surface of the mold 2 is set providing a deep level difference D than the coating off Irumu 6 as shown in FIG. As shown in FIG. 1, the bead shape 8 is formed with a width slightly larger than the width of the covering film 6.
[0019]
Further, as shown in FIG. 3, the coating film 6 is provided with a substantially semicircular concave shape 9 as a concave shape at a portion corresponding to the runner 5. The radius of curvature of the concave shape 9 is set to be larger than the radius of curvature of the bead shape 8 of the mold 2. The term an arc length of claims 2 "cross section edge length" indicates to the recess shape in FIG. 3 is a described 9 and bead shape 8.
[0020]
While the type 1 and type 2 before molding is opened, set in the form of placing the cover off Irumu 6 to the mold surface of the mold 2. In that case, it sets so that the substantially semicircular recessed shape 9 of the coating film 6 may correspond to the position corresponding to the bead shape 8 provided in the mold 2. In this state, in the runner 5, the bead shape 8 and the concave shape 9 have different radii of curvature, so that a space K exists between the mold 2 and the covering film 6. Since the type 1 and type 2 Closing coating film 6 as shown in FIG. 4 are crushed are sandwiched by the mold split surfaces of the upper and lower runner 5, the coating film 6 is stretched by sagging occurs have you to run Na 5 To do. At that time, the greater is the radius of curvature of the concave shape 9 for a radius of curvature of the bead shape 8, the recess shape 9 of the covering film 6 is set along the bead shape 8. Thereafter, the molten resin M is injected, when it reaches the end face of the cover film 6 while filling the runner 5, the cover film 6 in the step D by the pressure in the Y direction in FIG. 2 of the molten resin M pressed against the mold 2 The molten resin M does not flow between the coating film 6 and the mold 2. Thus, it prevents the molten resin flows on both sides of the coating film 6, will face the coating fill arm 6 that can integrally molded.
[0021]
Example 2
7 to 10 show a second embodiment of the present invention. FIG. 7 is an enlarged view of a portion d in FIG. 6 and shows the side gate portion in the injection mold of the present invention. FIG. 8 is a cross-sectional view taken along the line ee in FIG. FIG. 9 is a sectional view taken along line ff in FIG. 7 and shows the state of the film before clamping, and FIG. 10 is a sectional view taken along line ff in FIG. 7 and shows the state where the film is fixed after clamping. Show.
[0022]
Near the support Idogeto 4 of the mold surface of the mold 2 in the present embodiment, forming the groove 11 of the V-shape as shown in FIGS. 9 and 10 as a concave shape to the end portion of the filling direction of the resin La runner 5 To do. The portion facing the groove 11 of the front Symbol V-shape of the mold surface of the mold 1 provided with film fixing pin 10 as shown in FIGS. 9 and 10. The film fixing pin 10 presses the coating film 6 against the mold 2 and fixes it at the time of mold clamping.
[0023]
In situations that type 1 and type 2 before molding is opened, set in the form of placing the covering film 6 on the mold surface of the mold 2. In the state before the mold is closed, a space K exists between the mold 2 and the covering film 6 in the runner 5. When the mold 1 and the mold 2 are closed, as shown in FIG. 10, the covering film 6 is sandwiched and crushed by the upper and lower mold dividing surfaces of the runner 5, so that the covering film 6 is stretched and slack occurs in the runner 5. In this case, at the end of the molten resin filling direction X of the runner 5 film fixing pin 10 space K is collapsed by pressing the coating off Irumu 6 in the mold 2. Therefore, if the molten resin M is reached is injected into the end face of the covering film 6, which is more fixed in the coating film 6 is a film fixing pin 10 as shown in FIG. 8, and the V-type 1 Since the coating film 6 is present on the bottom surface of the groove 11 having the shape, the coating film 6 is pressed in the direction of the mold 2 by the pressure in the Y direction of the molten resin M in FIG. 8, and the molten resin M flows between the coating film 6 and the mold 2. There is nothing. Therefore, the coating film planned surface of the injection molded article in this Togana Ino molten resin turns to the back surface of the coating film 6 is that it is integrally molded.
[0025]
In addition, as for the form of the set for the film mold, the positional relationship between the film and the mold is not limited to the case of the vertical mold opening and the positional relationship between the film and the mold is up and down as in the embodiment. In this case, since the effects of the present invention can be obtained, the scope of the claims of the present application is included.
[Brief description of the drawings]
1 is a side gate portion of a first embodiment of the present invention. FIG. 2 is a sectional view taken along the line aa in FIG. 1 showing a resin filling state. FIG. 3 is a sectional view taken along the line bb in FIG. FIG. 4 is a cross-sectional view taken along the line bb in FIG. 1 and is a state of the film after clamping. FIG. 5 is a cross-sectional view taken along the line cc in FIG. 1. FIG. FIG. 7 is a side gate portion of Example 2 of the present invention. FIG. 8 is a sectional view taken along line ee of FIG. 7 showing a state of resin filling. FIG. 9 is a sectional view taken along line ff of FIG. Fig. 10 is a sectional view taken along line ff of Fig. 7 and shows the state of the film after clamping. Fig. 11 shows an example of a direct gate for a large product. Fig. 12 shows a conventional film. FIG. 13 is a sectional view taken along the line gg of FIG. 12. FIG. 14 is an enlarged view of the runner portion of FIG. 13, and the film is crushed by clamping. Figure Description of the sign] indicating the
1, 2 ... Mold 3 ... Product 4 ... Gate 5 ... Runner 6 ... Covering film 7 ... Sprue 8 ... Bead shape (recessed shape)
9 ... Recessed shape 10 ... Film fixing pin 11 ... Groove (recessed shape)
12 ... Direct gate

Claims (5)

Set the film that will cover one side of the product at the completion of molding on the mold surface of one mold that forms the product space, and then form the gate and the other mold so that it is continuous when clamping An injection molding method in which a film and a product are integrally formed by covering the part of the runner facing a part of the runner with the film and filling a molding material from the runner to the product space through a gate. ,
Each of the mold and one of the mold surfaces on which the film is to be set is previously formed with a concave shape in a portion facing the runner,
When setting the film on the mold surface of the one mold, in the mold clamping state after film setting, match the recess shapes with each other so that the film spans the groove width of the runner continuous to the gate,
An injection molding method characterized in that the film and the product are integrally formed after the mold is clamped in this state to bring the concave shapes into close contact with each other.   2. The injection according to claim 1, wherein an edge length of a cross section constituting the concave shape formed in the film is shorter than an edge length of a cross section constituting the concave shape formed on the mold surface of one mold. Molding method.   The injection molding method according to claim 1 or 2, wherein a step difference deeper than the thickness of the film is provided in the concave shape formed on the mold surface of one of the molds. Set the film that will cover one side of the product at the completion of molding on the mold surface of one mold that forms the product space, and then form the gate and the other mold so that it is continuous when clamping An injection molding method in which a film and a product are integrally formed by covering the part of the runner facing a part of the runner with the film and filling a molding material from the runner to the product space through a gate. ,
While forming the concave shape in advance at the end of the part facing the runner out of the mold surface of one mold where the film is to be set,
A film fixing pin is provided in a portion facing the concave shape in the mold surface of the other mold,
When the mold is clamped after setting the film on the mold surface of the one mold, the film is pressed with the film fixing pin against the recess shape facing the runner while the film spans the groove width of the runner continuous to the gate. Close contact
An injection molding method comprising integrally molding a film and a product in that state. The film that will cover one side of the product at the completion of molding is set on the mold surface of one mold that forms the product space, and when it is clamped, it is formed on the other mold so that it is continuous with the gate. An injection mold in which the film and the product are integrally formed by covering the part of the runner facing the part with the film and filling the molding material from the runner to the product space through the gate. Because
While forming a concave shape at the end of the part facing the runner out of the mold surface of one mold where the film is to be set,
A film fixing pin is provided on a portion of the mold surface of the other mold facing the concave shape,
An injection mold characterized in that, at the time of clamping, a film is pressed against a recess shape facing the runner with a film fixing pin to be brought into close contact therewith.

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