JP3552593B2 - Metal integrated resin molding method - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to a metal-integrated resin molding method and apparatus for integrally molding a resin with metal.
[0002]
[Prior art]
2. Description of the Related Art The technique of integrally molding a metal component and a resin by injection molding or the like is widely used in addition to insulation of a metal component such as a mechanical component such as a rotary bearing or a cable connecting portion in an optical submarine repeater. In these mechanical parts, electric parts, and the like, peeling at the interface between the metal part and the resin part due to shrinkage of the resin, shrinkage of the resin part, generation of internal distortion, and generation of voids become problems.
[0003]
FIG. 5 is a view schematically showing a molding machine described in JP-A-59-24620, which discloses a thick resin molding method for suppressing internal distortion and shrinkage. In FIG. 5, reference numerals 1 and 2 denote vertically divided dies, which are integrally held by a mold clamping force P during the molding process. 3 is a cavity, 19 is an injection cylinder, 20 is a gate, 21 is a movable core, and 22 is a piston.
[0004]
In the molding method using the molding machine shown in FIG. 5, the molds 1 and 2 are integrally held by a mold clamping force P, the temperature is raised to an injection temperature, resin is poured from an injection cylinder 19, and a piston 21 is pushed up to raise a gate. The resin is melted by closing the mold 20 and raising the temperature of the molds 1 and 2 and then rapidly cooled to around the glass transition temperature, then gradually cooled near the glass transition temperature, and simultaneously the movable core 21 is pushed up by the piston 22. It solidifies while applying pressure to the cavity 3.
[0005]
[Problems to be solved by the invention]
In the case of using the movable core as in the conventional resin molding method described above, the mold structure becomes complicated, the mold becomes large, and furthermore, it is necessary to close the gate in order to apply pressure by the movable core. Therefore, when the resin becomes insufficient due to the contraction of the resin, the resin cannot be supplied.
[0006]
In addition, when the present invention is applied to resin molding integrated with a metal component, separation at the interface between the metal component and the molding resin becomes a problem.
[0007]
Further, it can be applied to resin molding of a simple shape, but is not suitable for resin molding of a complicated shape.
[0008]
In addition, there is a problem that a large pressing force is required when the area of the molded product is large.
[0009]
The present invention solves the above-described problems, does not require a movable core, suppresses shrinkage due to resin shrinkage, reduces internal distortion, and can prevent separation at the interface between the resin and the metal component. it is intended to provide a metal-integral resin formed form process.
[0010]
[Means for Solving the Problems]
According to the first aspect of the present invention, a metal component is installed in a cavity formed by the upper and lower molds, and the mold and the metal component are set to a temperature 30 to 30 ° C. below the melting point or the glass transition temperature of the resin material to be resin-molded at normal pressure. A first step of heating the molten resin material to a first temperature higher by 100 ° C. and injecting the molten resin material into the cavity at a predetermined first pressure, and immediately after completion of the first step, 50 to 1000 kg / cm ² A second step of applying pressure at a second pressure and holding the mold and metal parts until they are stabilized at the first temperature; and holding the second pressure while holding the mold and metal parts. A third step of cooling to a second temperature 10 to 30 ° C. higher than the melting point or the glass transition temperature and maintaining the mold and metal parts until the temperatures of the mold and the metal parts are stabilized at the second temperature; Hold mold pressure and mold temperature A fourth step of cooling the metal component to a third temperature lower than the melting point or glass transition temperature while maintaining the second temperature, and maintaining the entire mold at the second pressure, or A fifth step of increasing the pressure to a pressure higher than the second pressure and cooling to the third temperature .
[0012]
The invention according to claim 2 is the metal-integral resin molding method according to the first aspect, in which oxide film is formed by chemical conversion treatment to the metal parts of the surface to be installed.
[0013]
The invention according to claim 3 are those which are surface roughened by the in claim 1 metal-integral resin molding method according, metal parts of the surface to be installed chemical treatment or mechanical means.
[0014]
The invention according to claim 4 is intended to apply in metal integrally resin molding method according to the first aspect, the thermosetting to the metal parts of the surface to install the adhesive.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to FIGS . 1 to 4 , but the present invention is not limited to these embodiments.
Embodiment 1 FIG.
FIG. 1 is a cross-sectional view schematically showing a metal-integrated resin molding apparatus according to Embodiment 1 of the present invention. In the figures, 1 and 2 are upper and lower molds, 3 is a cavity, 4 is a runner, 5 is a sprue (resin supply path), 6 is a heater provided in the molds 1 and 2, and 7 is molds 1 and 2. The dies 1 and 2 are heated by dies heating means such as the heater 6 and cooled by dies cooling means such as passing water through the water holes 7. Numeral 8 denotes a metal part molded integrally with the resin, and shows a state in which the molds 1 and 2 are installed in the cavity 3 formed by clamping the mold. In this case, the metal part 8 passes through the inside 9 of the cylindrical metal part 8. A metal component cooling means (not shown in the figure) for cooling the metal component 8 by watering is provided. Measuring units for measuring the temperatures of the dies 1 and 2 and the metal component 8 are provided, respectively, and the temperature control unit 10 controls the temperatures of the dies 1 and 2 and the metal component 8 independently. This temperature control is performed by heating by the heater 6 and cooling by passing water. Reference numeral 11 denotes an injection cylinder, a heater 12 for melting the resin material supplied from the resin material supply port 16 into the cylinder 14, a hydraulic cylinder 17 having a pressure control unit, and a hydraulic cylinder 17 for stirring the molten resin 13 and And a screw 15 that injects the molten resin 13 in conjunction with the screw 17.
[0016]
The process of the resin molding with a metal integrally resin molding apparatus shown in FIG. 1, the time of 3 - temperature change, time 4 - pressure changes, based on the cross-sectional view schematically showing the state of melting and solidification of FIG explain.
[0017]
First, in the first step, the metal component 8 is set in the cavity 3, the upper and lower molds 1 and 2 are clamped, and the heater 6 uses the temperatures of the molds 1 and 2 and the metal component 8 for resin molding. The resin material is heated to a first temperature T1 that is 30 to 100 ° C. higher than the melting point or the glass transition temperature of the resin material at normal pressure, and is pressed from the injection cylinder 10 by the hydraulic cylinder 16 at the first pressure P1, and the molten resin 13 is sprue 5, It is injected into the cavity 3 via the runner 4 (t0-t1). The first pressure P1, the comparison molten resin 12 to flow into the cavity 3 of the mold 1 may be a size that contact with the metal parts 8 in a molten state, usually 10 to 200 / cm ² Inject at very low pressure.
[0018]
Next, in the second step, immediately after the completion of the injection, pressure is applied at a second pressure P2 of 50 to 1000 kg / cm ² (t1−t2), and the metal component 8 and the molds 1 and 2 are heated at the first temperature T1. By holding until stable, the molten resin 13 in the molds 1 and 2 is made uniform.
[0019]
Next, in the third step, while maintaining the second pressure P2, the metal component 8 and the molds 1 and 2 are heated to a second temperature 10 to 30 ° C. higher than the melting point or glass transition temperature of the resin material at normal pressure. The temperature is cooled down to the temperature T2, and is maintained until the temperatures of the metal component 8 and the molds 1 and 2 are stabilized at the second temperature T2 (t2-t3). The cooling in this case is performed by the metal component cooling means that allows the water to flow through the water hole 7 and the inside of the metal component 8. When the metal component 8 is solid, a metal component cooling means such as bringing a cooling member into contact with the metal component 8 is possible. With the cooling in the third step, contraction of the molten resin 13 occurs, but by maintaining the molten resin 13 at the second pressure P2, the molten resin insufficient due to the contraction is supplied.
[0020]
Next, in the fourth step, the metal component 8 is cooled by the metal component cooling means at a temperature lower than the melting point or the glass transition temperature of the resin material at normal pressure while maintaining the second pressure P2 and the temperature T2 of the molds 1 and 2. Cool to the third temperature T3 (t3-t4). By this fourth step, as shown in FIG. 2 , the molten resin 13 is solidified from the metal component 8 side to form a layer in intimate contact with the metal component 8, and a mold including the sprue 5 and the runner 4 is formed. Since the side is in a molten state or a semi-molten state, replenishment of the insufficient molten resin due to contraction due to solidification of the molten resin 13 is performed by the second pressure P2.
[0021]
Next, in a fifth step, the entire molds 1 and 2 are cooled to a third temperature T3 (t4 to t5), and the pressing force is increased to a third pressure P3 = 500 to 1500 kg / in conjunction with this cooling. Increase the pressure to cm ² . In the fifth step, as shown in FIG. 2 , the resin is solidified also from the mold side, but the resin in the runner 4 portion is replenished due to shrinkage during melting or semi-melting due to shrinkage. Thereafter, by cooling to room temperature, the metal-integrated resin molding is completed. Note that the pressure in the fifth step does not necessarily need to be increased to P3, and may be kept at the second pressure P2 when the viscosity of the molten resin 13 is low.
[0022]
The resin material used for the metal-integral resin molding of the present invention is a thermoplastic material such as a low-density polyethylene resin (melting point: about 110 ° C.), polypropylene (melting point: about 170 ° C.), polystyrene (glass transition temperature: about 100 ° C.). Any resin can be used, and the first, second and third temperatures (T1, T2 and T3) are determined by their melting points or glass transition temperatures.
[0023]
Various metals such as copper, copper alloy, iron, and iron alloy can be used as the metal to be formed integrally with the resin, and the metal is not limited.
[0024]
Embodiment 2 FIG.
In the second embodiment, the resin molding process is the same as in the first embodiment. The difference from the first embodiment is that a chemical conversion treatment is applied to the surface of the metal component in contact with the resin before the resin molding.
[0025]
A mixed solution prepared by mixing 100 g of sodium hypochlorite, 100 g of caustic soda and 1 liter of water is prepared. The temperature of the mixed solution is raised to 85 ° C., and a metal part made of copper or a copper alloy material such as brass, beryllium copper, phosphor bronze is immersed in the heated solution for 1 to 2 hours. An oxide film is formed on the component surface. The metal part having the oxide film formed thereon is integrally formed with the resin as in the first embodiment.
By this chemical conversion treatment, the adhesion between the metal component and the resin can be improved.
[0026]
Embodiment 3 FIG.
In the second embodiment, the adhesion to the resin is improved by forming an oxide film on the surface of the metal component, but the same effect can be obtained even if the surface of the metal component is roughened.
[0027]
A metal part made of copper or a copper alloy material such as brass, beryllium copper, phosphor bronze or the like is immersed in a mixed acid of concentrated nitric acid and concentrated hydrochloric acid 1: 3 for 5 seconds and etched to roughen the surface of the metal part.
[0028]
Further, a mechanical method such as blasting may be used. The blasting is performed, for example, by spraying SiC having a particle size of about 10 μm onto the surface of the metal component at an air pressure of 5 kg / cm ² .
A metal part having a roughened surface is integrally molded with a resin as in the first embodiment.
[0029]
In the second and third embodiments, the surface of the metal component is subjected to a chemical conversion treatment or a blasting process. However, a thermosetting adhesive such as an epoxy resin is applied to the metal component to be installed in the cavity in advance. The same effect can be obtained.
[0030]
【The invention's effect】
According to the first aspect of the present invention, immediately after resin injection, pressure is applied at a pressure of 50 to 1000 kg / cm ² , the temperature is maintained until the temperatures of the mold and metal parts are stabilized , and the pressure of 50 to 1000 kg / cm ² is maintained. The mold and metal parts are cooled to a temperature that is 10 to 30 ° C. higher than the melting point or glass transition temperature of the resin at normal pressure, and are further held until the temperatures of the mold and metal parts are stabilized, thereby causing shrinkage by cooling. Insufficient resin can be replenished, the pressure of 50 to 1000 kg / cm ² is maintained, and the temperature of the mold is maintained at 10 to 30 ° C. higher than the melting point or glass transition temperature of the resin at normal pressure. By cooling only the part to a temperature lower than the above melting point or glass transition temperature, it solidifies from the metal part side to bring the resin and metal part into close contact with each other, Since that supplementation leaving the resin to insufficient I, together with the improved adhesion raw metal part and the resin to suppress shrinkage, thereby reducing the internal stresses.
[0032]
According to the second, third and fourth aspects of the invention, the adhesion between the metal and the resin can be further improved.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view schematically illustrating the configuration of a metal-resin integrated resin molding apparatus according to the present invention.
FIG. 2 is a diagram showing a temperature change in a resin molding step of the present invention.
FIG. 3 is a diagram showing a temperature change in a resin molding step of the present invention.
FIG. 4 is a diagram illustrating the state of solidification of the resin in the resin molding step of the present invention.
FIG. 5 is a cross-sectional view schematically showing a conventional resin molding apparatus.
[Explanation of symbols]
1, 2 molds, 3 cavities, 4 runners, 5 sprues (resin supply path), 6 heaters, 7 water holes, 8 metal parts, 9 inside metal parts, 10 temperature control unit, 11 injection cylinder, 12 heaters, 13 molten resin, 14 cylinder, 15 screw, 16 resin material supply port, 17 hydraulic cylinder, 18 pressure control unit, 19 injection cylinder, 20 gate, 21 movable core, 22 piston

Claims (4)

A metal part is placed in a cavity formed by the upper and lower molds, and the mold and the metal part are heated at a first temperature 30 to 100 ° C. higher than the melting point or glass transition temperature of the resin material used for resin molding at normal pressure. A first step of injecting the molten resin material into the cavity at a predetermined first pressure, and applying a second pressure of 50 to 1000 kg / cm ² immediately after the completion of the first step. A second step of pressing and holding the mold and the metal part at the first temperature until the mold and the metal part are stabilized at the first temperature, and holding the mold and the metal part at the melting point or the glass transition temperature while maintaining the second pressure. A third step of cooling to a second temperature higher by 10 to 30 ° C. and maintaining the temperature of the mold and metal parts until the temperature of the mold and the metal parts is stabilized at the second temperature; and a mold maintaining the second pressure and maintaining the second pressure. Temperature at the second temperature. A fourth step of cooling the metal part to a third temperature lower than the melting point or the glass transition temperature while maintaining the second pressure, or maintaining the second mold under the second pressure or higher than the second pressure. A step of increasing the pressure to a pressure and cooling to the third temperature. 2. The method according to claim 1 , wherein an oxide film is formed on the surface of the metal component to be installed by a chemical conversion treatment. 2. The method according to claim 1 , wherein the surface of the metal component to be installed is roughened by chemical conversion treatment or mechanical means. 2. The method according to claim 1 , wherein a thermosetting adhesive is applied to the surface of the metal component to be installed.

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