JPH07186186A - Resin molding and method and apparatus for molding resin - Google Patents

Abstract

PURPOSE:To preclude unnecessary wall thickness parts from being molded even in the case where two color molding is performed by separating the inner part of a cavity in the rear side of an undercut part. CONSTITUTION:In a resin molding method in which one movable mold 20 is successively combined to a first and second fixed mold 11, 12 and a first and second molding are conducted in turn in each fixed mold. In the first molding, resin molding is effected in the form of a movable separator 24 provided on the movable mold 20 projecting into the inner part of a cavity 21a in the rear side of the undercut part, and in the second molding, molding is effected by retreating the movable separator 24 from aforesaid cavity 21a. In this manner, there is no need to mold any grooves for inserting the fixed separator 14 into the undercut part, so that the formation of unnecessary wall thickness parts caused by such grooves can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin molded product integrally molded with different resins, and more particularly to a resin molded product having an improved molding shape at the boundary between two color resins of a resin molded product having an undercut portion. , A resin molding method and a resin molding apparatus thereof.

[0002]

2. Description of the Related Art Generally, in the two-color molding method, after molding a resin of one color in a first mold, the molded product is set in a second mold, and a different color is used. This is a method of obtaining a molded product in which resins of respective colors are integrated by molding with a resin (which may be a resin of the same color in some cases). As a molding apparatus for performing this two-color molding method, for example, FIG.
As shown in the conceptual diagram,
Two-color molding including a fixed die 10 in which 1 and a post-forming die 12 are arranged in parallel, and two movable dies 20 of the same structure mounted on a rotary table 2 which is rotated about the axis thereof. There is a device.

In this molding apparatus, one movable mold 20 is opposed to the pre-driving mold 11 to form a first mold (cavity), where the first color resin is molded. afterwards,
The movable die 20 together with the molded product is released from the pre-driving die 11 by the rotary table 2, and the rotary table 2 is further rotated and moved to the post-punching die 12.
And the movable mold 20 constitute a second mold (cavity),
By performing resin molding of the second color here, it becomes possible to obtain a resin molded product in which the resins of the first and second colors are integrated. Since the two movable molds 20 mounted on the rotary table 2 have the same structure, the above-mentioned molding operation is performed by using the respective movable molds.
It is possible to continuously mold the lens by simultaneously performing the molding and the post-forming die 12 at the same time.

A lens RCL of a combination lamp for automobiles is one that is molded by such a two-color molding method. 5 (a) and 5 (b) are a perspective view and a cross-sectional view of an example thereof, and a tail lamp lens (hereinafter, tail lens) TLL molded with a red resin and a turn signal lamp lens (molded with an amber resin ( Hereinafter, the turn lens) TSL is integrally resin-molded. A seal leg portion S used when attaching the lens RCL to the lamp body is projected in the rear surface direction around the entire periphery of the rear surface of the lens. Also,
Tail lens TLL and turn lens TS on the back of the lens
A rib RB having a uniform height is formed at the boundary with L. This rib RB is shown in FIG. 5 (c) as CC of FIG. 5 (a).
As shown in the sectional structure along the line, when the lens RCL is viewed from the outer surface side, the contour of each lens is formed,
In addition, the ribs RB can be seen with uniform brightness over the entire length, which is effective in improving the appearance of the lens. Also,
In this lens, one side portion of the lens RCL is curved with a large curvature due to the design requirement, and therefore the curved portion and the seal leg portion S formed along this portion are formed in the die removing direction. It is configured as an undercut portion SS which is overhanged and which makes it difficult to remove the mold.

A method for molding the lamp lens RCL having the undercut portion SS by a two-color molding method will be described. FIG. 6 shows a pre-driving die 1 as the fixed die 10.
FIG. 3 is a perspective view showing the unfolded mold 1, the post-molding mold 12, and the movable mold 20. Movable die 20, leading die 11 and trailing die 1
2, cavities 21, 13 and 15 for forming lenses by cooperation of the two are formed. Then, a fixed separator 14A for partitioning the turn lens area 13b and the tail lens area 13a is formed on the pre-casting die 11 using only a part of the formed cavity 13, and this partitioning is performed. Amber resin can be injected into the cavity of the turn lens region 13a.

The post-molding die 12 is not provided with a fixed separator and is constructed so that a red resin for molding the tail lens can be injected. A so-called slider 22 is provided on the movable mold 20 to mold the undercut portion SS provided on the lamp lens RCL, and the molded lens is released from the movable mold 20. When the slide 22 is moved, this portion is removed from the undercut portion of the lens to enable release. As will be described later, the slider 22 is provided with a groove 27 into which a part of the fixed separator 14 is inserted so as to partition the turn lens region 13b and the tail lens region 13a in the undercut portion.

Therefore, in this two-color molding method, the movable die 20 is opposed to the die for preforming to form the first die, and the amber resin is injected into the cavity defined here. Then, the amber turn lens TSL can be molded by the cavity of the turn lens region 13b partitioned by the fixed separator 14. Then
By forming the second mold by making the movable mold 20 face the post-molding mold 12 together with the molded product, and by injecting the red resin into the cavity of the tail lens region 13a defined therein, first, The red tail lens TLL is molded integrally with the formed turn lens TSL.

[0008]

In such a two-color molding method, the fixed separator 14 for partitioning the turn lens and the tail lens has the undercut portion of the seal leg S provided on the back side of the slider 22. It is necessary to extend to a cavity portion (hereinafter referred to as an under cavity portion) 21a for molding the SS. However, in such an undercut portion, the slider 22
Is formed in an overhang state along the undercut shape with respect to the die removing direction. Therefore, in order to separate the undercavity portion 21a, the slider 22
It is necessary to form a groove 27 in the direction of die removal in the mold and to allow a part 14a of the fixed separator 14 to advance to the under cavity portion 21a through this groove 27.

For this reason, when the resin is molded with the post-driving die 12 in which the fixed separator 14 does not exist after the molding with the pre-driving die 11, the groove provided in the movable die 20 is used. Since the groove 27 is not filled with the fixed separator, the groove 27 is configured as a part of the cavity 21, and the groove 27 is filled with the red resin. As a result, in the molded lens, as shown in FIG. 7, a thick portion X having the same shape as the groove 27 is formed on the inner surface of the boundary portion between the turn lens TSL and the tail lens TLL. Become. This thick part X
Is originally unnecessary, and when the lens RCL is viewed from the outside, the thick portion X becomes different in transmitted color and reflected color from the rib RB portion, and the appearance of the lamp looks good. Is causing the decrease.

Therefore, in order to improve the appearance, it is necessary to remove the thick portion X after molding, and if such a cutting process is required in addition to the two-color molding process, it will be used for a lamp. This complicates the manufacturing process of the lens and causes an increase in cost. In addition, the appearance of the cut surface may be deteriorated unless the cut surface is processed with high quality.
An object of the present invention is to provide a resin molding method and a resin molding apparatus that prevent unnecessary thick portions from being molded in the undercut portion even when the undercavity portion is separated and two-color molding is performed. It is in.

[0011]

Means for Solving the Problems The resin molded product of the present invention is
An undercut portion formed in a resin molded product in which different resins are integrally formed adjacent to each other does not have a thick wall portion at a boundary portion of each resin. In this case, ribs having a uniform height are provided along the boundary of each resin, and both resins are integrated on the opposing surfaces of these ribs. In the resin molding method of the present invention, one movable mold is sequentially combined with the first and second fixed molds, and the first molding and the second molding are performed in each fixed mold.
When performing molding sequentially, resin molding is performed with the movable separator provided on the movable mold protruding into the cavity on the back side of the undercut portion of the movable mold in the first molding, and the movable separator in the second molding. Is retracted from the cavity and molding is performed. Further, in the resin molding apparatus of the present invention, one movable mold is sequentially combined with the first and second fixed molds,
In a resin molding apparatus that sequentially performs the first molding and the second molding in each fixed mold, the movable mold is allowed to advance and retreat into a cavity formed between the movable mold and the fixed mold, and to advance. It has a movable separator that divides the inside of the cavity into a first molding region and a second molding region when being pressed.

[0012]

Since there is no thick portion at the boundary between different resins in the undercut portion, the appearance of the molded product is improved. Performing the first molding with the movable separator protruding to define the cavity on the back side of the undercut portion, and then retracting the movable separator and performing the second molding to reach the cavity on the back side of the undercut portion. It is not necessary to provide a fixed separator that reaches the fixed mold, and thus, a groove for inserting the fixed separator in the undercut portion is not necessary, and unnecessary thick-walled portions due to the groove are prevented from being formed.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. In this embodiment, an example in which the lamp lens shown in the above figure is molded by two colors is shown. FIG. 1 shows a fixed mold 10,
That is, each fixed die of the first die 11 and the second die 12,
It is a conceptual perspective view showing a pair of movable molds 20 having the same structure. Here, the movable mold 20 and the fixed mold 10 are arranged in parallel with each other, such as the two-color molding device shown in FIG. Two movable molds with the same structure are mounted on a rotary table that rotates in the same direction.

Then, the movable die 20 on one side is replaced with the die 1 for pre-strike.
1 to form a first mold, where amber-color resin molding is performed, and thereafter, the movable mold 20 is moved upward to separate from the pre-driving mold 11 together with the molded product, and the rotary table is set. It is rotated and moved to the post-forming die 12, and this time the post-forming die 12 and the movable die 20 compose a second mold, and the red resin molding is performed here, whereby the first and the second die are formed. It is assumed that the lamp lens RCL as shown in FIG. 5 in which the resins of the two colors are integrated can be obtained.

Further, the pre-casting die 11 is provided with a fixed separator 14 which divides the inside of the cavity 13 into a tail lens area 13a and a turn lens area 13b. This fixed separator 14 is an under cavity portion (under) of the lens. It is configured such that it is not provided so as to extend up to the cavity portion for molding the seal leg portion on the back side of the cut portion). The post-forming die 12 has a cavity 15 similar to that shown in FIG.

On the other hand, in FIG. 2, the movable die 20 is replaced with the fixed die 10 (1
1 and 12) in a state of being combined with each other, and the movable mold 20 has a tail lens TL similar to that shown in FIG.
A cavity 21 capable of integrally molding L and the turn lens TSL including the rib RB is formed, and a portion corresponding to an undercut portion of the lens is also configured as a slider 22 as in the conventional case, and is internally provided in a mold body. The slide is moved in the direction of arrow A in the figure by the plunger 23. In addition, in the cavity portion that is wrapped around the lower side of the slider 22, that is, in the mold body along the under cavity portion 21a, a movable separator 24 that isolates both the tail lens and the turn lens is provided at the boundary portion between the tail lens and the turn lens. It is provided.

That is, the movable separator 24 is provided in a state of being embedded in the mold body, and is moved in the direction of arrow B in the figure by the plunger 25 provided in the mold body. In this case, when the movable separator 24 is most protruded, the tip of the movable separator 24 abuts against the lower surface of the slider 22 to separate the under cavity portion 21a into two regions, that is, the tail lens and the turn lens. Is located on the bottom surface of the under cavity portion 21a so that this portion communicates with two regions. 26
Is a guide of the slider 22. Therefore, in the movable die 20, the under cavity portion 21 a can be isolated by the movable separator 24, so that the fixed separator 14 provided in the fixed die 10 is separated from the under cavity portion 21.
It is not necessary to extend to a, and thus it is not necessary to provide the movable slider 22 with the groove 27 as shown in FIG. 6 for guiding the fixed separator 14 to the under cavity portion 21a.

Next, a process of performing two-color molding using such a movable mold and a fixed mold will be described. First, one movable mold 2
0 is combined with the pre-driving die 11 of the fixed die 10 to form the first die. At this time, the inside of the cavity is separated by the tail lens and the turn lens by the fixed separator 14 provided in the pre-casting die 11, and at the same time, as shown in FIG.
As shown in (a), the movable separator 24 of the movable die 20 is in a position where it is projected by the plunger 25, and the movable cavity 24 separates the under cavity portion 21a into the tail lens and the turn lens. Then, by injecting amber resin into the cavities, the resin is filled only in the turn lens region 13b isolated by the fixed and movable separators 14 and 24 among all the cavities of the first mold, As a result, the amber turn lens TSL is resin-molded. Then, by moving the movable die 20 upward, the molded turn lens TSL is released from the pre-driving die 11 integrally with the movable die 20.

Thereafter, similarly to the molding apparatus shown in FIG.
The rotating table is rotated to move the movable mold 20 and the turn lens T.
The SL is moved to the post-die 12 and this post-die 11 and the movable die 20 form a second die. At this time, as shown in FIG. 3B, the movable separator 24 is retracted from the under cavity portion 21a by the plunger 25. As a result, the turn lens TSL that has already been molded is housed inside the cavity formed in the second mold, and by utilizing one side surface of the turn lens TSL, the tail lens TLL is provided inside the cavity 15. The cavity is defined.

Therefore, the tail lens TLL can be molded by injecting the red resin into the cavity in the region other than the area where the turn lens TSL is occupied in the second mold, and the tail lens TLL is integrated with the turn lens TSL. And the two-color lens RCL for the lamp is molded. At this time, since the groove is not formed in the slider 22 of the movable die 20, the groove does not exist as a part of the cavity 21, and thus the thick portion X as shown in FIG. 7 is formed. There is no such thing.

After that, as shown in FIG.
By moving the two-color lens RCL integrally with the post-casting die 12, and thereafter the slider 22 is moved obliquely downward by the plunger 23 to move the slider 22 from the undercut portion 21a. The overhung part of is saved and the mold release is possible. The two movable dies 2 mounted on the rotary table 2 shown in FIG.
Since 0 has the same configuration, the molding operation of the lens RCL is continuously performed by simultaneously performing the above-described molding operation using the movable die and the pre-die 11 and the post-die 12, respectively. It goes without saying that is possible.

[0022]

As described above, in the resin molded product of the present invention, since there is no unnecessary thick portion at the boundary between different resins, the appearance of this portion is not deteriorated. In particular, a rib having a uniform height is provided at the boundary, and both resins are integrated by this rib, so that the appearance of the boundary can be further enhanced. Further, in the resin molding method of the present invention, in the first molding of the two-color resin molding, the resin molding is performed in a state where the movable separator provided in the movable mold is projected into the cavity on the back side of the undercut portion of the movable mold, In the second molding, since the movable separator is retracted from the cavity to perform molding, it is not necessary to provide the fixed mold with a fixed separator reaching the cavity on the back side of the undercut portion, and thus the fixed separator is inserted into the undercut portion. A groove for causing the groove is not necessary, and unnecessary rib formation due to the groove is prevented. Further, the resin molding apparatus of the present invention is capable of advancing and retreating into the cavity formed between the fixed mold and the back side of the undercut portion, and when it is advanced, the cavity is formed with the first molding region and the second molding region. A movable separator that is divided into a molding region is provided in the movable mold, and the first and second moldings are performed by changing the movable position of the movable separator, so that an unnecessary thick portion is not molded. Molding of resin molded products can be realized.

[Brief description of drawings]

FIG. 1 is a perspective view showing a schematic configuration of a fixed die and a movable die of a resin molding apparatus of the present invention.

FIG. 2 is a cross-sectional view of a state where a mold is composed of a movable mold and a pre-driving mold of the present invention.

FIG. 3 is a process cross-sectional view for explaining the resin molding method of the present invention.

FIG. 4 is a conceptual perspective view of a two-color molding apparatus to which the present invention is applied.

FIG. 5 is a perspective view and a cross-sectional view of a two-color molded lamp lens.

FIG. 6 is a perspective view showing a schematic configuration of a fixed mold and a movable mold of a conventional resin molding device.

FIG. 7 is a partially enlarged perspective view for explaining unnecessary ribs generated in a lamp lens molded by a conventional molding method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Fixed mold 11 Pre-driving mold 12 Post-driving mold 13,15 Cavity 14 Fixed separator 21 Cavity 21a Undercut part 22 Slider 24 Movable separator

Claims (4)

[Claims] 1. A resin molded product formed by integrally forming different resins adjacent to each other, wherein a thick wall portion is not provided at a boundary portion of each resin in an undercut portion generated in the molded product. Molded resin products. 2. The resin-molded article according to claim 1, wherein each resin has ribs of uniform height along the boundary of each resin, and the two resins are integrated on the opposing surfaces of the ribs. 3. One movable mold is sequentially combined with a first and a second fixed mold, and the first molding and the second molding are performed in each fixed mold.
In the resin molding method of sequentially performing molding, in the first molding, resin molding is performed with the movable separator provided in the movable mold protruding into the cavity on the back side of the undercut portion of the movable mold, and the second molding is performed. Then, the resin molding method is characterized in that the movable separator is retracted from the cavity for molding. 4. One movable die is sequentially combined with a first and a second fixed die, and in each fixed die, the first molding and the second molding are performed.
In a resin molding apparatus that sequentially performs molding, the movable die is configured to be capable of advancing and retracting into a cavity formed between the movable die and a fixed die on the back side of the undercut portion, and when the advancing is performed, the movable die is moved into A resin molding device having a movable separator which is divided into a first molding region and a second molding region.