JPH07100851A - Manufacture of synthetic resin component - Google Patents

Abstract

PURPOSE:To preferably plate by forming an opening in the rear surface of a handle for press injecting a gas into a cavity, enclosing the opening by thermal fusion-bond sealing, and then plating a molded form. CONSTITUTION:Each time a sufficient amount of synthetic resin is press injected into a cavity 14, gas pressure is applied to the resin in the cavity 14 from the rear surface to be pressed to the inner surface of molds, and a molded form becomes hollow. Accordingly, an opening 33 for feeding gas remains on the rear surface of the form. A trowel 40 having a spherical recess formed at an end is brought into contact with the lip 31 of the opening 33, and the lip 31 is melted and brought into close contact. Accordingly, the opening 33 is completely closed to prevent cleaning water, plating solution from being penetrated. Therefore, the form can be preferably plated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a synthetic resin part, and more particularly to a method for producing a hollow synthetic resin part which can be plated.

[0002]

2. Description of the Related Art For example, a vehicle outdoor handle has a handle body and a pair of arm portions projecting from the handle body. In order to pivotally attach the outdoor handle to the escutcheon, a hole for mounting the axle is provided at the end of the arm portion. When the outdoor handle is made of a synthetic resin, a “sink” is formed on the surface of the handle body at the connecting portion between the handle body and the arm portion. In the past, such "sink" was prevented by reducing the wall thickness. Further, as disclosed in Japanese Utility Model Publication No. 2-19485, a method has been proposed in which a lightening hole is provided in a connecting portion between an outside handle and an arm portion.

Further, for example, as shown in JP-A-5-118170 and JP-A-5-177680, a hollow resin molded product applied to a synthetic resin door handle as an automobile synthetic resin component is manufactured. The method of doing is proposed. Therefore, a conventional manufacturing method will be described with reference to FIGS. As shown in FIG. 5, the molding die 10 has a fixed die 11 that forms a cavity 14 and a movable die 12. The fixed mold 11 is supplied with fluidized synthetic resin. The gate 1 is formed between the nozzle 13 and the cavity 14.
5 are provided. The movable mold 12 can move along a guide 16 between a mold closing position and a mold releasing position,
FIG. 5 shows the movable mold 12 in the mold clamping position. The movable die 12 is formed with a gas injection passage 17 communicating with the cavity 14.

By using the mold 10, the door handle 20 shown in FIG. 6 can be formed. The door handle 20 has a front surface 21 exposed to the outside of the vehicle from a door (not shown), a rear surface 22 arranged toward the inside of the door, and a pair of arm portions 23 and 24 extending rearward from the rear surface 22. A hole 25 for inserting a shaft for attaching the door handle 20 to a handle escutcheon or a bracket and a hole 26 for connecting a rod connecting to a lock device are formed at an end of the arm portion 23. Further, the arm portion 24 is formed with a hole 27 through which a shaft attached to an escutcheon or a bracket is inserted.

In the above structure, first, FIG. 5 and FIG.
As shown in FIG. 9, the synthetic resin 30 fluidized into the cavity 14 of the molding die 10 from a portion corresponding to the rear surface 22 of the door handle 20 is, for example, 60 MPa (600 kgf / 600 kgf /
Press in at a first level pressure (square centimeters).
For example, as shown in FIG. 8, the synthetic resin 30 may be press-fitted from the end of the arm 23 or 24. After a sufficient amount of fluidized synthetic resin 30 has been pressed into the cavity 14,
As shown in FIG. 7, from a portion corresponding to the rear surface 22 of the door handle 20 to a pressure lower than the first level pressure, for example, 2
A gas pressure of nitrogen, carbon dioxide, air, or other inert gas is applied to the synthetic resin 30 in the cavity 14 at a second level pressure of 0 MPa (200 kgf / square centimeter). As a result, the synthetic resin 30 in the cavity 14 is pressed against the inner surface of the molding die 10 at the portion corresponding to the front surface 21 of the door handle 20. Next, the synthetic resin molded product is taken out from the cavity 14. In the method of manufacturing the door handle 20, when the gas pressure is applied, for example, the arm portion 23 and / or
Alternatively, hollow portions 23a, 24a having an L-shape, a mouth-shaped cross section or a U-shaped cross section can be formed in an appropriate portion such as 24. Although this hollow portion is formed when the gas is pressurized, it contributes to the weight reduction of the door handle 20.

By applying pressure to the synthetic resin 30 in the cavity 14 with the second level pressure, the door handle 2
The synthetic resin 30 in the cavity 14 is pressed against the inner surface of the molding die 10 at a portion corresponding to the front surface 21 of 0. As a result, the surface of the cavity 14 of the molding die 10 can be faithfully transferred, and a molded product having no sink mark and no warp can be formed. In addition, as shown in FIGS. 10 and 11,
When a gas pressure is applied, a hollow part 23 is formed in a part of the synthetic resin part.
By forming a and 24a, it is possible to reduce the weight of the molded product. Further, since it is not necessary to form a lightening hole in the connecting portion such as the arm or the rib, sufficient mechanical strength can be secured.

[0007]

By the way, in the above-mentioned conventional method, since the gas is pressed into the cavity, the opening 33 is formed on the back surface of the door handle 20, as shown in FIG. The opening 33 remains in the door handle 20 as it is after the gas is pressed. Therefore, when the door handle 20 is subsequently plated, the etching solution and the plating solution enter the door handle 20 through the opening 33, resulting in defective plating and insufficient chromium plating being formed on the surface of the resin. There is.

Therefore, an object of the present invention is to provide a method of manufacturing a hollow synthetic resin part which can be plated well.

[0009]

A method of manufacturing a synthetic resin part according to the present invention comprises a step of pressurizing a fluidized synthetic resin into a cavity of a mold from a portion corresponding to a rear surface of the synthetic resin part, and After a certain amount of fluidized synthetic resin has been pressed into the cavity, the gas pressure is applied to the synthetic resin in the cavity from the portion corresponding to the rear surface of the synthetic resin component to the portion corresponding to the front surface of the synthetic resin component. In the above step, a step of pressing the synthetic resin in the cavity against the inner surface of the molding die, a step of taking out the hollow synthetic resin molded article from the cavity, and a step of closing the opening of the hollow synthetic resin molded article. The step of closing the opening includes the step of performing a heat-welding seal by pressing a heated trowel against the lip of the opening. This method of manufacturing a synthetic resin part may include a step of subjecting the heat-sealed and sealed synthetic resin molded product to a plating treatment.

[0010]

[Function] Since the opening is closed by the heat welding seal,
The hollow synthetic resin molded product can be satisfactorily plated without water, the etching liquid, and the plating liquid penetrating into the synthetic resin molded product.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a heat-sealing seal in a method of manufacturing a synthetic resin part according to the present invention applied to a synthetic resin door handle for an automobile will be described below with reference to FIGS.

As shown in FIGS. 1 and 2, after the door handle 20 having the opening 33 is obtained, the door handle 2
In a state in which 0 is fixed, a trowel 40 heated to about 260 degrees is attached to the cylindrical lip portion 31 formed around the opening 33.
Press for seconds. The door handle 20 is made of a mixture of polycarbonate and ABS resin, ABS resin or ABS.
The resin is molded with a mixed resin of PPO (polyethylene oxide or polypropylene oxide) and PBT (polybutylene terephthalate). A spherical depression 41 is formed at the tip of the trowel 40, and the lip portion 31 is melted and brought into close contact. Therefore, the opening 33 is completely closed as shown in FIG. Therefore, the product with the opening 33 closed can prevent moisture such as rain or wash water from entering. Further, even if the door handle 20 is plated thereafter, the opening 33 is closed, so that the etching solution and the plating solution do not enter. Therefore, the resin molded product used in the present invention is a thermoplastic resin.

FIG. 4 is a sectional view showing another embodiment. In this embodiment, the step portion 32 may be formed inside the lip portion 31.

The embodiment of the present invention is not limited to the above-mentioned embodiment, but can be modified. For example, although an example in which it is used for manufacturing a door handle as a synthetic resin part for automobiles is shown, the present invention can be applied to other synthetic resin parts such as handles other than the door handle and knobs.

[0015]

According to the present invention, since the hollow resin molded product can be favorably plated, the manufacturing yield can be improved.

[Brief description of drawings]

[Figure 1] Side view of resin molded product

2 is a front view of FIG.

FIG. 3 is a side view of the present invention in which an opening is heat-sealed.

FIG. 4 is a sectional view showing another embodiment of the present invention.

5 is a cross-sectional view of a molding die used in the method of manufacturing a synthetic resin part for automobiles, taken along the line C-C in FIG. 7.

FIG. 6 is a perspective view of a door handle manufactured by a method for manufacturing a synthetic resin part for automobiles.

7 is a sectional view taken along the line AA of FIG.

FIG. 8 is a sectional view taken along line BB of FIG.

FIG. 9 is a schematic view showing a position where resin is press-fitted.

FIG. 10 is a perspective view of a door handle manufactured by a method for manufacturing a synthetic resin part for an automobile.

11 is a cross-sectional view taken along the line DD of FIG.

[Explanation of symbols]

10 ・ ・ Molding die, 11 ・ ・ Fixed die, 12 ・ ・ Movable die, 1
3 ... Nozzle, 14 ... Cavity, 15 ... Gate,
16 ... Guide, 17 ... Gas injection path, 20 ... Door handle, 21 ... Front, 22 ... Rear, 23, 24 ...
Arm part, 30 ... Synthetic resin, 31 .. Lip part, 33
..Openings, 40 ... Irons, 41 ...

Claims (3)

[Claims] 1. A step of pressurizing fluidized synthetic resin into a cavity of a molding die from a portion corresponding to a rear surface of a synthetic resin part, and a step of pressuring a sufficient amount of fluidized synthetic resin into the cavity. , A step of pressing the synthetic resin in the cavity against the inner surface of the molding die in the portion corresponding to the front surface of the synthetic resin component by applying gas pressure to the synthetic resin in the cavity from a portion corresponding to the rear surface of the synthetic resin component, A method for producing a synthetic resin part, which comprises the steps of: taking out a hollow synthetic resin molded product from the cavity; and closing the opening of the hollow synthetic resin molded product. 2. The method for manufacturing a synthetic resin part according to claim 1, wherein the step of closing the opening includes a step of performing heat-welding sealing by pressing a heated trowel against a lip of the opening. . 3. The method for producing a synthetic resin part according to claim 1, further comprising the step of subjecting the heat-sealed synthetic resin molded article to a plating treatment.