JP3431879B2 - Molding method and molding die apparatus for resin molded article - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of molding a resin molded product having a punching portion such as a speaker grill having a large number of openings concentratedly and a molding die device, and a punching block corresponding to the punching portion. The present invention relates to a molding method and a molding apparatus for a resin molded body, which can reliably prevent breakage, improve moldability, and prolong the life of a mold.

[0002]

2. Description of the Related Art Generally, as shown in FIG. 12, a speaker grill 2 is provided on the lower front side of an automobile door trim 1.
Recently, when the door trim 1 is molded, a large number of openings are intensively formed at predetermined locations to integrally mold the speaker grill 2.

When the speaker grill 2 is integrally molded with the door trim 1, a molding die unit 3 shown in FIG. 13 is used. This molding die device 3 is composed of a cavity mold 4, a core mold 5, and an injection molding machine 6 connected to the core mold 5, and an injection molding machine is provided in a cavity formed by the cavity mold 4 and the core mold 5. It is possible to mold the door trim 1 into a desired curved shape along the shape of the mold after supplying the molten resin from the mold 6 and to mold the speaker grill 2 on the door trim 1 at the same time. Punching block 7, for both mold 4 and core mold 5,
8 is provided, and the speaker grill 2 is integrally formed by abutting the punching blocks 7 and 8.

That is, as shown in FIG. 14, the abutting surfaces of the punching blocks 7 and 8 provided in the mold portion corresponding to the speaker grill 2 of the door trim 1 are
While the uneven portions 7a and 8a are formed, the core-side punching block 8 is configured to be vertically movable by the cylinder 9, and the core-side punching block 8 is moved upward by driving the cylinder 9 before the molten resin is injected and filled. The punching blocks 7 and 8 are lifted, and the punching blocks 7 and 8 maintain the abutting state when the molten resin is filled.

At the time of mold press molding, the core side punching block 8 is lowered by the cylinder 9 in response to the cavity die 4 descending to the bottom dead center, and the core side punching block 8 is the die of the core die 5. Make up the surface,
Good molding is performed.

[0006]

As described above, according to the prior art, the core side punching block 8 is pushed up in advance, and the punching blocks 7 and 8 are butted against each other during the lowering operation of the cavity mold 4, so that the door trim 1 is attached to the door trim 1. Although it is possible to mold the speaker grill 2 at the same time, the cavity side punching block 7 has a hardness of 40 ~.
45 (HRC) high carbon steel is used, and the core side punching block 8 uses porous ceramics with hardness of 30 to 35 (HRC) to escape the gas at the time of molding to the outside. , 8 have different hardnesses, when the door trim 1 is mass-produced, the core side punching block 8 is damaged due to the pressing load, and the durability of the die is significantly reduced, and the core side punching is also performed. It has been pointed out that if molding is performed while the block 8 is damaged, a large number of defective products are generated and the product yield is significantly reduced.

The present invention has been made in view of the above circumstances. In a resin molded body integrally provided with a punching portion having a large number of openings, such as a speaker grill, a metal mold for the punching portion is provided. With a view to prolonging the life of the molding die by effectively preventing the damage of the molding die, and to provide a molding method of the resin molding and a molding die device which improve the yield of the molded product. There is.

[0008]

In order to achieve the above object, the invention according to claim 1 of the present application is to supply a molten resin into a cavity formed by a cavity mold and a core mold, and mold-clamp the resin. In addition to molding a molded body into a required shape, a resin molded body integrally provided with a punching portion in which a large number of openings are intensively formed at predetermined locations of the resin molded body by punching blocks provided in a cavity mold and a core mold, respectively. When the molds of the cavity mold and the core mold are opened, the upper surface of the core side punching block is located above the mold surface of the core mold, the cavity mold descends, and the cavity side punching block and core After reaching the minute clearance between the side punching block and the side of the punching block, keep the minute clearance between the punching blocks The punching block on the core side descends in tandem with the supply of molten resin into the cavity, and then the resin mold is molded into the required shape by clamping the cavity mold and core mold, and at the same time the punching block molds the punching part. It is characterized by doing so.

Therefore, according to the invention described in claim 1,
When the distance between both punching blocks reaches a minute clearance as the cavity type descends, the punching block on the core side works in synchronism with the lowering operation of the cavity type, so that both punching blocks may come into contact with each other. Absent. Therefore, even when the porous ceramic having relatively low strength is used as the material of the core side punching block, the core side punching block is not damaged.

According to the second aspect of the present invention, the minute clearance between the punching blocks is 2/100 to 3 /.
It is characterized by being 100 mm.

According to a third aspect of the present invention, there is provided a molding die device for a resin molded body integrally provided with a punching portion for forming a large number of holes in a concentrated manner. The core mold on the fixed side, an injection molding machine connected to the core mold, and a punching block provided in the cavity mold and the core mold corresponding to the punching portion, and the cavity side punching block is made of hard steel material. while, the core side punching block, a porous steel and material, is vertically movable by a driving cylinder, and the cavity mold is lowered, after the punching block each other reaches the small clearance, the core side punching block
And the cavity type are linked to each other by the linking mechanism .
One punching block maintained micro clearance
With the core side punching block
It is characterized by lowering to .

Therefore, according to the invention of claim 3,
Since a connecting mechanism is used between the cavity mold and the core side punching block, the cavity side punching block and the core side punching block do not come into contact with each other,
Damage to the punching block on the core side can be prevented as much as possible.

In the invention according to claim 4 of the present application, the connecting mechanism is fixed to the piston rod of the cylinder for driving the punching block, and is provided on the mold plate that moves up and down in the core mold and on the mold surface of the cavity mold. It is composed of a push-in pin and a contact pin protruding from the mating plate in correspondence with this push-in pin.The lowering operation of the cavity mold causes the press-in pin to press the contact pin downward, and the core side punching block is pushed through the mating plate. It is characterized in that it is linked to the cavity type.

Therefore, according to the invention of claim 4,
When the clearance between the cavity side punching block and the core side punching block reaches a minute clearance as the cavity type moves down, the push pin provided in the cavity type is applied to the matching plate installed on the core side. By pushing the pin downward, the core-side punching block descends in synchronization with the lowering operation of the cavity type via the piston rod connected to the mating plate. Therefore, the cavity side punching block and the core side punching block are clamped while maintaining a minute clearance, and both punching blocks do not come into contact with each other, so that the core side punching block is not damaged.

According to a fifth aspect of the present invention, there is provided a molding die device for a resin molded body integrally provided with a punching portion in which a large number of holes are intensively formed, and a cavity mold on the movable side, It is composed of a fixed core side, an injection molding machine connected to the core mold, and a cavity block and a punching block provided in the core mold, and the cavity side punching block is made of hard steel while the core The side punching block has a high-strength portion on the periphery of the porous portion,
A minute clearance is set between the cavity side punching block and the porous portion of the core side punching block when both punching blocks are abutted.

Therefore, according to the invention of claim 5,
The core side punching block is made of porous steel such as porous ceramic, which is relatively inferior in strength, but hard carbon steel such as high carbon steel is used on the periphery, and the portion made of porous steel is the cavity side. Since a small clearance is set between the punching block and the punching block, when the punching block is abutted, the hard steel materials on the peripheral edges of the cavity side punching block and the core side punching block abut against each other, resulting in a porous steel material with poor strength. Since is in a non-contact state, damage to the punching block can be prevented.

The invention according to claim 6 of the present application is characterized in that the minute clearance is 2/100 to 3/100 mm.

Therefore, according to the invention of claim 6,
Since the minute clearance is set to 2/100 to 3/100 mm, the molten resin does not invade in this minute clearance, so that the core side punching block can be prevented from being damaged and the formability is not hindered. .

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a method for molding a resin molded body and a molding die apparatus according to the present invention will be described in detail below with reference to the accompanying drawings.

1 and 2 are a front view and a cross-sectional view showing an automobile door trim manufactured by the method of the present invention, and FIG. 3 is a cross-sectional view showing the overall construction of a first embodiment of a molding die apparatus according to the present invention. 4 is a plan view showing a core die of the molding die apparatus, FIG. 5 is a sectional view showing a connecting mechanism in the molding die apparatus, and FIG. 6 is a time of a cavity die and a core side punching block in the molding die apparatus. FIG. 7 is a chart showing each step of an embodiment of the method of the present invention, FIG. 7 is an explanatory view showing a state before the punching block hits, and FIG. 8 shows a state when the molten resin is injected. FIG. 9 is an explanatory diagram showing a mold press molding process.

10 and 11 show a second embodiment of the molding die apparatus according to the present invention. FIG. 10 is an explanatory view showing the overall structure, and FIG. 11 is an enlarged cross-sectional view showing the main part. is there.

First, referring to FIGS. 1 and 2, an automobile door trim 10 manufactured by applying the method of the present invention is made of a resin molding molded into a desired curved shape by mold press molding. A speaker grille 20 is molded at the bottom with the door trim 10.

The door trim 10 is formed by molding press molding polypropylene resin mixed with talc, pigment, etc., into a desired curved surface shape. If desired, a laminate in which a surface material is pasted on a surface of a resin core material. In that case, it is preferable to use, as the skin material, a laminated sheet material having a good cushioning property in which the back surface of a TPO (thermoplastic olefin) sheet is lined with polyethylene foam, and the skin material is a resin. The core material is integrally attached during mold press molding.

As described above, according to the present invention, since the speaker grille 20 is integrally formed with the door trim 10, it is not necessary to attach a separate speaker grille to the door trim 10, so that the number of assembling steps can be simplified and the external appearance can be improved. The door trim 10 and the speaker grille 20 can be made to appear as one, and the appearance is also preferable.

The present invention is based on the speaker grill 20.
Door trim 1 with punching part (portion with multiple holes) like
In the case of simultaneous molding to 0, by reducing the press load in the punching part of the mold, the durability of the mold is increased,
In addition, it is characterized in that molding defects and the like due to damage to the mold are prevented in advance.

As to one embodiment of the method of the present invention, the molding method of the door trim 10 described above will be described below with reference to FIG. 3 to FIG.

As shown in FIG. 3, the molding die device 30 is
A cavity mold 40 that can move up and down, a fixed-side core mold 50 that makes a pair with the cavity mold 40, and an injection molding machine 60 that is connected to the core mold 50 and supplies a molten resin are roughly configured.

More specifically, the cavity mold 40 can be moved up and down by a predetermined stroke by the lifting cylinder 41, and has a mold surface shape conforming to the curved shape of the product surface of the door trim 10, and the core mold 50 is Injection molding machine 6
A hot runner 51 and a gate 52, which serve as passages for molten resin from 0, are provided, and have a mold surface substantially the same as the mold surface shape of the cavity mold 40.

In the present invention, the door trim 1
Cavity side punching block 42 and core side punching block 53 are formed on the cavity die 40 and the core die 50, respectively, in order to integrally form the speaker grille 20 into the speaker die 20.
Is provided and both punching blocks 42, 5 are provided.
The features of the present invention are that the punching blocks 42 and 53 are reliably prevented from being damaged when the three collaborate with each other, thereby prolonging the life of the molding die device 30 and improving the molding accuracy.

That is, the cavity-side punching block 42 is substantially the same as the outer shape of the speaker grill 20 and has an uneven portion 43 having convex portions corresponding to a plurality of opening shapes.
Are provided on the facing surface side of the core side punching block 53, and the cavity side punching block 42 is
The material is high carbon steel with high hardness.

On the other hand, the core side punching block 53 is
In order to effectively discharge the gas generated during molding to the outside,
Porous steel material, such as porous ceramics, having a relatively low strength is used, and the surface of the core side punching block 53 facing the cavity side has uneven portions that match a plurality of opening shapes of the speaker grill 20. 54 is formed, and the speaker grille 20 is shaped by the abutting action of the cavity side punching block 42 and the core side punching block 53.

The core side punching block 5
3 is attached to the tip of the piston rod 55a of the drive cylinder 55 when the molten resin is supplied, because it is necessary to maintain the punching state, and it can move up and down so that it can abut.

Further, in the present invention, in order to effectively suppress the damage of the core side punching block 53 which is inferior in strength during punching, the core side punching block 53 has the following connecting mechanism.

That is, as shown in FIGS. 4 and 5, the alignment plate 56 is attached to the piston rod 55a of the drive cylinder 55 so as to be substantially horizontal, and the alignment plate 56 located outside the product cavity C is attached. The contact pins 57 are attached upward at the four corners, and the tips 57a of the contact pins 57 are provided at the openings 50a of the core mold 50.
From the outside.

On the other hand, the cavity die 40 corresponding to the contact pin 57 is provided with a push pin 44 projecting downward on the mold surface, and the length dimensions of the contact pin 57 and the push pin 44 are as follows. When the cavity die 40 descends, the clearance between the cavity side punching block 42 and the core side punching block 53 is 2/100 to 3/100 m.
The size is adjusted so that the push pin 44 and the contact pin 57 come into contact with each other when reaching m. Then, if the cavity die 40 continues to descend, the push-in pin 44 enters the die through the opening 50a of the core die 50 and presses the contact pin 57 downward, and accordingly, the mating plate 56 descends. , The core side punching block 53 descends in synchronization with the descending stroke of the cavity mold 40 via the piston rod 55a.

Next, a method of molding the automobile door trim 10 shown in FIGS. 1 and 2 by using the molding die device 30 having the above-described structure will be described. Regarding the molding of the door trim 10, in the time chart diagram of FIG. 6, a time chart of the cavity die 40 (including the cavity side punching block 42) and a time chart of the core side punching block 53 are shown. In FIGS. Will be described.

First, when the cavity mold 40 and the core mold 50 are in the mold open state (shown in FIG. 5), in the time chart shown in FIG. 6, the cavity mold 40 is at point (a) and the core side punching block 53 is At the point (g), the core-side punching block 53 projects to the uppermost position.

Then, the lifting cylinder 41 operates,
The cavity mold 40 performs a predetermined stroke lowering operation,
As shown in FIG. 7, the cavity side punching block 4
2 and the core-side punching block 53 (see FIG. 7).
(Indicated by medium code d) reaches 2/100 to 3/100 mm, the core side punching block 53 is point (h) in the time chart of FIG.

At this time, the tips 44a of the push-in pins 44 provided on the cavity die 40 come into contact with the tips 57a of the contact pins 57 attached upward at the four corners of the mating plate 56 provided on the core die 50. .

Further, the cavity mold 40 continues the descending operation, and as shown in FIG. 8, the cavity mold 40 and the core mold 50.
When the clearance reaches 10 to 30 mm, the molten resin M is distributed and supplied from the injection molding machine 60 to the mold surface of the core mold 50 through the hot runner 51 and the gate 52.

In the time chart shown in FIG. 6 when the molten resin M is supplied, the cavity mold 40 is located from point (b) to point (c), and the core side punching block 53 is located from point (i) to point (j). Move to each.

Further, the push pin 44 pushes the contact pin 57 in synchronism with the lowering movement of the cavity mold 40 before reaching the point (b), and accordingly, the matching plate 5 is moved.
6 descends, mating plate 56 and piston rod 55
Core side punching block 5 integrated via a
3 also descends by the same stroke as the descending stroke of the cavity mold 40, so that both punching blocks 42,
53 micro clearances (2/100 to 3 / 100m
m) is kept constant.

After that, by the operation of the lifting cylinder 41,
As shown in FIG. 9, the cavity mold 40 descends to the bottom dead center, and the door trim 10 and the speaker grill 20 are simultaneously molded. In the time chart diagram shown in FIG.
The cavity mold 40 moves from the point (d) to the point (e), and the core-side punching block 53 moves from the point (k) to the point (l). Even at this time, the cavity mold 40 is moved downward by the connecting mechanism described above. The punching block 5 on the core side corresponds to the stroke of descending to the dead point (d).
3 also descends by the same stroke, and the clearance (2/100 to 3/100 mm) between the cavity side punching block 42 and the core side punching block 53 is constant at this time as well.

When the molding is completed, in the time chart shown in FIG. 6, the cavity die 40 moves up to the point (f), and the core side punching block 53 moves to the point (m) by the operation of the driving cylinder 55. Ascending, the state shown in FIG. 5 is reached, and molding is continued.

As explained above, the punching block 53 on the core side is also synchronized with the same stroke by the connecting mechanism composed of the push-in pin 44, the contact pin 57, and the mating plate 56 according to the descending motion of the cavity mold 40. Since the operations are linked, the molding is completed with the minute clearance between the cavity-side punching block 42 and the core-side punching block 53 always maintained at a constant level. Weak core side punching block 53
It is possible to effectively solve the conventional inconvenience that the molding die is broken, prolong the life of the molding die device 30, and prevent the molding failure due to the damage from occurring.

The minute clearance between the cavity side punching block 42 and the core side punching block 53 is 2/100 to 3/100 m in this embodiment.
Although the m is set to m, if the clearance exceeds 5/100 mm, the molten resin may flow in, impairing moldability, and if the clearance is less than 1/100 mm, it may strike due to variations during processing, Since there is a risk of breakage, it can be said that a clearance of 2/100 to 3/100 mm is preferable as a result of taking into account variations in assembly and variations in dimensions.

Next, FIGS. 10 and 11 show a second embodiment of the molding die apparatus 30 according to the present invention. In the second embodiment, the core side punching block 53 is provided.
The structure of the above has been devised, and like the first embodiment,
The linking mechanism linked to the operation of the cavity mold 40 can be eliminated. The same parts as those in the first embodiment are designated by the same reference numerals,
Detailed description is omitted.

According to this embodiment, as shown in FIG. 11, the shape and material of the cavity side punching block 42 are the same as those of the first embodiment, but the core side punching block 53 has a porous portion at the center. While adopting a two-divided structure of 53a and peripheral high-strength portion 53b, the high-strength portion 53b and the cavity-side punching block 42 are both high-strength materials as in the prior art, so while having an abutting structure, The porous portion 53a and the cavity-side punching block 42 are aligned with each other while maintaining a minute clearance of 2/100 to 3/100 mm.

Therefore, as shown in FIG. 10, when the cavity mold 40 and the core mold 50 are in the mold open state, the core side punching block 53 is in the protruding state by the operation of the driving cylinder 55, and then the cavity is opened. When the cavity-side punching block 42 and the core-side punching block 53 come into contact with each other due to the lowering operation of the die 40, the core-side punching block 53 has a high-strength portion 53b at the periphery thereof butts against the cavity-side punching block 42, but has a poor strength. Since the portion 53a does not abut the cavity side punching block 42, the punching block 53 can be effectively prevented from being damaged and the formability can be improved, which is the same effect as that of the first embodiment.

Further, in the embodiment shown in FIGS. 10 and 11, since the connecting mechanism such as the mating plate 56, the contact pin 57 and the pushing pin 44 can be eliminated,
There is also an advantage that the structure of the molding die 30 can be simplified.

In the embodiment described above, the speaker grill 20 is integrally formed on the door trim 10 made of a resin molded body. However, the door trim 10 has a laminated structure in which a skin material is attached to the surface of the resin core material. Alternatively, the speaker grill 20 may be replaced by a structure having an air draft hole formed in an interior component.

[0052]

As described above, according to the present invention, when simultaneously forming punching holes such as a speaker grill and an air draft hole in a resin molded body, punching is performed by avoiding butting of the punching blocks. Since the breakage of the block can be suppressed, it is possible to prolong the life of the molding die, and it is possible to prevent the defective molding due to the breakage of the punching block.

[Brief description of drawings]

FIG. 1 is a front view showing an automobile door trim manufactured by the method of the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is an overall view showing a first embodiment of a molding die device according to the present invention.

FIG. 4 is a plan view of a core mold in the molding die device shown in FIG.

5 is a sectional view taken along line VV in FIG.

FIG. 6 is a time chart diagram of a cavity mold and a core side punching block in the method of the present invention.

FIG. 7 is an explanatory diagram showing a state in which a minute clearance is reached between the punching blocks in the method of the present invention.

FIG. 8 is an explanatory view showing a state at the time of injection of molten resin in the method of the present invention.

FIG. 9 is an explanatory view showing a mold press molding step in the method of the present invention.

FIG. 10 is an overall view showing a second embodiment of the molding die device according to the present invention.

11 is an enlarged cross-sectional view of a punching block in the molding die device shown in FIG.

FIG. 12 is a front view showing a conventional automobile door trim.

FIG. 13 is an explanatory view showing a conventional mold press molding die device.

FIG. 14 is an explanatory view showing a punching block in a conventional mold press molding die device.

[Explanation of symbols]

10 Automotive door trim 20 speaker grill 30 Mold 40 cavity type 41 Lifting cylinder 42 Punching block on cavity side 43 uneven part 44 Push pin 50 core type 51 Hot Runner 52 gate 53 Core side punching block 53a Porous part 53b High strength part 54 Concavo-convex part 55 Drive cylinder 56 Laminating plate 57 contact pin 60 injection molding machine C cavity M molten resin

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP 2000-6184 (JP, A) JP 11-1141 (JP, A) JP 8-118407 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B29C 45/26-45/37 B29C 33/00-33/76 B29C 43/36-43/42

Claims (6)

(57) [Claims] 1. A cavity mold (40) and a core mold (50).
Molten resin (M) in the cavity (C) formed by
Of the punching block (4) provided in the cavity mold (40) and the core mold (50), respectively.
2, 53) is a method for molding a resin molded body, in which a punching portion (20) having a large number of openings intensively formed at a predetermined position of the resin molded body (10) is integrally provided, and the cavity mold ( 40) and the core die (50) are opened, the upper surface of the core side punching block (53) is located above the die surface of the core die (50), the cavity die (40) descends, and the cavity side After the punching block (42) and the core-side punching block (53) reach the minute clearance, the punching block (4
2, 53) while maintaining a minute clearance, the core side punching block (53) descends in association with the lowering of the cavity mold (40), and the molten resin (M) is supplied into the cavity (C). Then, the resin mold (10) is molded into a required shape by clamping the cavity mold (40) and the core mold (50), and at the same time, the punching block (42,
53) A method for molding a resin molded product, characterized in that the punching part (20) is molded according to (53). 2. The method for molding a resin molded product according to claim 1, wherein the minute clearance between the punching blocks (42, 53) is 2/100 to 3/100 mm. 3. A molding die device (30) for a resin molding (10) integrally provided with a punching portion (20) for intensively forming a large number of holes, wherein a movable cavity mold (40) is provided. ) And the fixed core type (5
0) and an injection molding machine (60) connected to the core mold (50)
And a cavity mold (4
0) and a punching block (42, 53) provided on the core die (50). The cavity side punching block (42) is made of hard steel, while the core side punching block (53) is the porous steel is a material, is vertically movable by a driving cylinder (55), a cavity mold (40) is lowered, punching block (42, 53) after each other reaches the small clearance, the core side punching and the calibration <br/> Activity type (40) and its splice mechanism for cooperative action block (53),
Both punching blocks (42, 53) are finely cleared
Core side punching block (5
3) A mold apparatus for molding a resin molded body, characterized in that the mold 3) is lowered together with the cavity mold (40) . 4. A punching block (5)
3) A mating plate (56) fixed to a piston rod (55a) of a cylinder (55) for driving the cylinder (55) and moving up and down in the core mold (50), and a push pin ( 44) and a contact pin (57) protruding from the mating plate (56) corresponding to the push-in pin (44).
0) The pushing pin (44) pushes the contact pin (57) downward by the lowering movement of the core side punching block (53) and the cavity die (40) through the mating plate (56). The molding die device for a resin molded body according to claim 3, wherein 5. A molding die device (30) for a resin molding (10) integrally provided with a punching portion (20) having a large number of holes concentrated therein, the cavity mold (40) on the movable side. ) And the fixed core side (5
0) and an injection molding machine (6) connected to the core mold (50).
0) and punching blocks (42, 53) provided in the cavity die (40) and the core die (50), and the cavity side punching block (42).
Is made of hard steel, while the core-side punching block (53) has a high-strength portion (53b) at the periphery of the porous portion (53a), and both punching blocks (4
2, 53), but a minute clearance is set between the cavity side punching block (42) and the porous portion (53a) of the core side punching block (53). Molding equipment for body. 6. The minute clearance is 2/100 to 3/1.
It is 00 mm, The molding die apparatus of the resin molded body of Claim 5 characterized by the above-mentioned.