JPH11179754A - Injection weld molding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an injection weld molding method capable of uniformly applying the pressure of a bonding resin to the whole of the bonding parts of primary molded products to obtain sufficient weld strength and preventing the damage of the primary molded products. SOLUTION: When the bonding parts 1a, 2a of primary molded products 1, 2 are mutually abutted in molds 3, 4 and a bonding resin R is injected into the weld grooves M formed to the peripheral edges of the bonding parts 1a, 2a to mutually weld the primary molded products 1, 2, the resin R is injected in such a state that the molds 3, 4 are slightly opened and the molds are clamped after filling to press the resin R charged in the weld groove M.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a previously molded 1
The present invention relates to an injection welding molding method for molding a hollow resin product such as a gasoline tank by abutting and welding the joints of the next molded product.

[0002]

2. Description of the Related Art Conventionally, as a method for molding such a hollow resin product, for example, as shown in FIG.
The joining parts 51a, 52a located at the opening-side ends of the primary molded articles 51, 52 each having a bottomed box shape and divided into three parts (may be divided into three or more parts) are formed by molding metal (not shown). In the mold, as shown in FIG. 6 (b), they are butted and welded into the welding groove M formed between the welding flanges 51b, 52b previously formed around the joints 51a, 52a.
By injecting the joining resin R from the injection molding machine and filling the welding groove M with the resin R, the joining portions 51a and 52 are formed.
There is a method of obtaining a hollow resin product by welding "a" and joining the primary molded products 51 and 52.

At this time, the joining resin R injected from the nozzle of the injection molding machine flows into the welding groove M from gates G1 and G2 provided at several places around the welding groove M as shown in FIG. The metal flows into the welding groove M through the flow path formed between the metal mold and the molding die.

[0004] As such an injection welding molding method, a method of continuously molding a primary molded article by sliding a mold and welding the primary molded articles to each other by secondary injection, and The structure of a mold used in such a method is disclosed in Japanese Patent Publication No. 2-38377.

[0005]

However, in the conventional injection welding molding as described above, a sufficient cross-sectional area for the flow of the joining resin R in the welding groove M is required. In order to secure an area, the projecting space of the welding flanges 51b and 52b must be increased, and the resin pressure increases immediately below the gates G1 and G2, but the flow ends of the joining resin flow. That is, since the pressure of the resin R decreases at an intermediate position between the gates G1 and G2, when the injection pressure is increased to obtain the welding strength at the intermediate position,
In the portion directly below the gates G1 and G2, the primary molded product 51,
There is a risk that the bonding resin R leaks into the inside due to breakage of the sealing member 52. If the injection pressure is reduced to avoid this, a defective welding portion occurs at an intermediate position, and sufficient welding strength is obtained. There is a problem that it may not be possible.

[0008] As shown in FIG.
When the abutting surfaces are cut obliquely to reduce the contact area in order to weld the entire surfaces of the abutting surfaces 1, 52, the amount of resin Re protruding toward the inner surface varies depending on the distance from the gates G1 and G2. There is a problem that
Solving these problems has been a problem in conventional injection welding molding.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems in the conventional injection welding molding, and it is possible to set the injection pressure of the joining resin low and to set the pressure of the joining resin to a gate. It is an object of the present invention to provide an injection welding molding method which can be sufficiently added to a position distant from the main body, can prevent breakage of a primary molded product, and can obtain sufficient welding strength.

[0008]

According to a first aspect of the present invention, there is provided an injection-welding molding method, wherein two or a joint portion of a primary molded product divided into two or more parts is abutted in a mold.
In the injection welding molding in which the joining resin is injected into the welding groove formed on the periphery of the joining portion and the primary molded products are welded to each other via the resin filled in the welding groove, the joining resin is injected into the welding groove. It is characterized in that, after injection, the resin filled in the welding groove is pressurized, and such a configuration in the injection welding molding method is a means for solving the above-mentioned conventional problems.

According to another aspect of the injection welding molding method of the present invention, when the joining resin is filled in the welding groove, the resin is injected with the mold opened, and the filling is performed. After the completion, the resin in the welding groove is configured to be pressurized by pressing the resin, and in the injection welding molding method according to the third embodiment, the bonding resin is injected into the welding groove and then provided in the mold in advance. The inserted pressing member is inserted into the welding groove to press the resin filled in the welding groove, and as a further embodiment, in the injection welding molding method according to claim 4, the joining member of the primary molded article is formed. In addition, a resin pool into which the resin extruded by pressurization flows is formed.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION An injection welding molding method according to the present invention is characterized in that a joining resin filled in a welding groove is pressurized in order to weld and join primary molded articles to each other at the time of injection. In order to compensate for the local pressure shortage and to eliminate the local strength shortage, the primary molded product is molded in advance by various molding methods such as injection molding. The next molded product can be set and joined to a welding die. Further, the die slide injection method as described in the above-mentioned Japanese Patent Publication No. 2-38377, that is, by sliding the mold, the primary molded articles are formed and then removed from the same mold without being taken out of the mold. You may make it join continuously by injecting a joining resin in a type | mold.

Further, as a specific method of pressing the filled resin, a method of injecting the resin with the mold slightly opened and closing the mold after the filling is completed, as described in claim 2, As described in claim 3, a method of pressing a piston-shaped pressing member provided on a mold into a welding groove filled with resin can be adopted.

The pressing member can be provided only at a position where pressure is required, such as a portion far from the gate, or can be provided over the entire length of the welding groove. Further, if necessary, it is possible to use both pressurization by mold clamping and pressurization by this pressing member.

[0013]

In the injection welding molding method according to the first aspect of the present invention, the joining resin injected to weld the primary molded products is pressurized in the welding groove. By setting the resin pressure at the time low, it is possible to prevent the primary molded product from being damaged immediately below the gate, and to apply necessary pressure to the portion remote from the gate after filling. An extremely excellent effect that no welding occurs and sufficient welding strength can be obtained is brought about.

According to a second aspect of the present invention, there is provided an injection molding method, in which the resin is injected with the mold opened while filling the welding groove with the joining resin. Since the resin filled in the welding groove is pressurized by closing the mold later, the resin pressure can be evenly applied to the entire joint of the primary molded product without requiring a special mechanism. Even when the entire surface of the butted surfaces is welded, the amount of resin protruding to the inner surface side can be made uniform, and the sectional area of the welding groove in the final product can be made small. In the injection welding molding method according to No. 3, the resin filled in the welding groove is pressed by inserting a pressing member provided in the mold in advance into the welding groove. , In particular and the distance portion far from the gate, it is possible to perform an effective pressing against butt persists shaped like portion forms an acute angle with respect to the mold clamping direction.

Further, in the injection welding molding method according to the fourth aspect of the present invention, a resin pool is formed at a joint portion of the primary molded product so that the resin extruded by pressure flows thereinto. It is possible to ensure the smoothness of the inner surface of the welded portion, and furthermore, it is possible to reliably melt the path until the resin for joining flows into the resin reservoir, thereby further improving the welding strength. Is brought.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings.

Embodiment 1 FIGS. 1 (a) and 1 (b) are process diagrams showing the procedure of an injection welding molding method according to an embodiment of the present invention.

First, as shown in FIG. 1A, primary moldings 1 and 2 are placed in molding dies 3 and 4, and joints 1a and 2a of these primary moldings 1 and 2 are opposed to each other. Set to state.

Steps are formed at the joints 1a and 2a so that they can fit into each other in a butt state in the form of a solder joint.
welding flanges 1b and 2a
b is provided, and a welding groove M is formed between the welding flanges 1b and 2b when the joints 1a and 2a abut against each other.

Next, one mold 3 is moved together with the primary molded product 1 with respect to the other mold 4, and the mold is clamped to a position where a compression margin G is left as shown in FIG. Thereafter, in this state, the joining resin R is injected from the nozzle N of the injection molding machine, and the welding groove M formed between the welding flanges 1b and 2b is formed.
Fill.

After the resin R is filled in the welding groove M, the mold is completely clamped while the resin R maintains fluidity, whereby the resin R in the welding groove M is pressurized.
As shown in (c), the primary molded products 1 and 2 are welded to each other.

According to this injection welding molding method, the resin R is pressurized by mold clamping after the filling is completed. Therefore, it is not necessary to set the injection pressure high, and the resin R filled in the welding groove M is not required. Is pressed at a uniform pressure irrespective of the distance from the gate, it is possible to prevent the primary molded products 1 and 2 from being damaged near the gate and to prevent the resin from leaking and the occurrence of poor welding.

Further, there is no need to provide a special mechanism or device for pressurizing the resin R, and the resin R flows with the dies 3 and 4 slightly opened as shown in FIG. Since only the cross-sectional area of the welding groove M is required, the cross-sectional dimension of the welded portion as the final product after the welding is completed can be reduced, and a compact product can be obtained.

In this embodiment, the example in which the hollow parts are formed by welding the primary molded products 1 and 2 has been described. However, the injection welding molding method of the present invention is limited to only the molding of the hollow parts. However, it goes without saying that the present invention can be widely applied to joining between resin products.

Embodiment 2 FIGS. 2 (a) and 2 (b) show another example of the butted shape at the joints 1a and 2a of the primary molded products 1 and 2 used in the injection welding molding method according to the present invention. Things.

In this embodiment, the joints 1a and 2a of the two primary molded articles are provided with concave and convex shapes which are fitted to each other in a butt state, and the projecting length of the convex formed on the joint 1a side is reduced. Since the depth is slightly shorter than the depth of the concave portion formed on the side of the joining portion 2a, the resin reservoir 5 is formed therebetween.

As in the case of the first embodiment, when the molds 3 and 4 are slightly opened, the joining resin R is injected as shown in FIG.
Is completely clamped.

As shown in FIG. 2B, the excess resin Re leaked from the welding groove M due to the pressurization based on the mold clamping enters the resin reservoir 5 from the gap between the fitting portions in the joining portions 1a and 2a. Because of the inflow, the inner surfaces of the primary molded products 1 and 2 do not overflow and the smoothness of the inner surfaces can be ensured. In addition, the resin R flows through the gap between the fitting portions, so that the passing portion is welded, so that bonding with higher strength can be performed.

Embodiment 3 FIGS. 3 (a) and 3 (b) show another example of the butt shape of the primary molded products 1 and 2, and in this embodiment, the joints 1a and 2a The joint surfaces 1a and 2a are designed to be welded by cutting the butted surfaces obliquely.

As in the above embodiment, when the molds 3 and 4 are slightly opened and the tips of the diagonally cut joints 1a and 2a are in contact with each other, as shown in FIG. R is injected into the welding groove M, and when the filling is completed, the molds 3 and 4 are completely clamped.

The joining portion 1 cut obliquely by the mold clamping
3a and 2a are deformed while melting and the entire surface is completely welded, and as shown in FIG. 3B, one extra resin Re leaked out by mold clamping is removed.
Although the resin R filled in the welding groove M is pressed by the uniform pressure over the entire length of the joints 1a and 2a, the resin R filled in the welding groove M overflows to the inner surface side. The amount of the resin Re can be constant regardless of the site.

Embodiment 4 FIGS. 4A and 4B show still another example of the butted shapes of the primary molded products 1 and 2 used in the present invention.

In this embodiment, the joints 1a and 2a of the primary molded products 1 and 2 are formed with butt portions cut obliquely as in FIG. Grooves 1c and 2c are formed on the sides, respectively, and function as a resin pool 5. The inner wall 2d on the joint portion 2a side forming the groove 2c is formed higher than the butted butted portion to block the resin Re overflowing to the inner surface side.

As in the third embodiment, when the molds 3 and 4 are slightly opened and the butted butted portions of the joining portions 1a and 2a are in contact with each other, as shown in FIG. When R is injected and filling is completed, mold 3
When the molds 4 and 4 are completely clamped, the obliquely cut butt ends are deformed and welded. At this time, FIG.
As shown in (b), the excess resin Re leaked out by pressurization by the mold clamping is retained in the groove 2c, that is, in the resin reservoir 5, so that the inner surfaces of the primary molded products 1 and 2 of the third embodiment. And the unwelded portion does not become a sharp notch as in the first and second embodiments, and the welding strength and durability are not impaired.

Embodiment 5 FIGS. 5 (a) and 5 (b) illustrate a procedure for pressurizing the resin R by inserting a pressing member as another embodiment of the injection welding molding method according to the present invention. The mold 3 used in this embodiment has, for example,
A pin 6 as a pressing member is attached to the welding flange 1 of the primary molded product 1 at a portion where poor welding due to insufficient pressure is expected to occur.
b, and is inserted into the welding groove M by a cylinder or cam provided outside the dies 3 and 4.

In this case, as shown in FIG. 5A, the joining resin R is injected into the welding groove M with the molds 3 and 4 clamped, and the inside of the welding groove M is filled with the resin R. After being done,
The pin 6 is inserted into the welding groove M to press the resin R in the welding groove M, thereby preventing the occurrence of welding failure and eliminating the insufficient welding strength. In this example,
Depending on the butted shape of the primary molded products 1 and 2 and the distance from the gate, it is possible to appropriately apply pressure to a portion where welding failure is likely to occur.

[Brief description of the drawings]

FIGS. 1 (a) to 1 (c) are process diagrams showing a procedure of an injection welding molding method according to a first embodiment of the present invention.

FIG. 2A is a cross-sectional view showing a butt shape at a joint of a primary molded product used in an injection welding molding method according to a second embodiment of the present invention. (B) It is sectional drawing which shows the joining state of the primary molded article shown to Fig.2 (a).

FIG. 3A is a cross-sectional view illustrating a butt shape at a joint of a primary molded product used in an injection welding molding method according to a third embodiment of the present invention. (B) It is sectional drawing which shows the joining state of the primary molded article shown to Fig.3 (a).

FIG. 4 (a) is a cross-sectional view showing a butt shape at a joint of a primary molded product used in an injection welding molding method according to a fourth embodiment of the present invention. (B) It is sectional drawing which shows the joining state of the primary molded article shown to Fig.4 (a).

FIGS. 5A and 5B are cross-sectional views showing shapes of a mold and a primary molded product used in an injection welding molding method according to a fifth embodiment of the present invention, and a joining procedure.

6 (a) and 6 (b) are perspective views showing a shape of a primary molded product in a conventional injection welding molding method.

FIG. 7 is a conceptual diagram showing an injection state of a joining resin in a conventional injection welding molding method.

FIG. 8 is a cross-sectional view showing another example of the shape of a primary molded product in a conventional injection welding molding method.

[Explanation of symbols]

 1, 1 Primary molded product 1a, 2a Joining part 3, 4 Mold (mold) 5 Resin pool 6 Pin (pressing member) M Welding groove R Joining resin

Claims (4)

[Claims] 1. One or two divided parts
The joining portions of the next molded products are abutted in a mold, the joining resin is injected into the welding groove formed on the peripheral edge of the joining portion, and the primary molded products are welded to each other via the resin filled in the welding groove. In the welding molding, an injection resin is injected into a welding groove, and then the resin filled in the welding groove is pressurized. 2. The method according to claim 1, wherein when filling the welding groove with the joining resin, the resin is injected while the mold is opened, and after the filling is completed, the resin is clamped to pressurize the resin in the welding groove. 2. The injection welding molding method according to 1. 3. After injecting the joining resin into the welding groove,
2. The injection welding molding method according to claim 1, wherein a pressing member provided in the mold in advance is inserted into the welding groove to press the resin filled in the welding groove. 4. The injection according to claim 1, wherein a resin pool into which the resin extruded by pressurization flows is formed at a joint of the primary molded product. Welding molding method.