JPH07180079A - Production of mold for slush molding - Google Patents

Abstract

PURPOSE:To easily impart rugged shapes to a forming surface side at the time of forming a mold for slush molding by an electroforming method. CONSTITUTION:A conductive layer E is formed on the surface of a pattern M. This pattern M is immersed into an electrolyte A which does not contain a surfactant and thereafter, an electroforming shell Ko of a prescribed thickness is formed while the adhesion of bubbles B on the pattern M is suppressed by an ultrasonic transmitter W. The operation of this ultrasonic transmitter W is thereafter stopped and the bubbles B are made to positively adhere to the surface of an electroforming shell Ko, by which an electroforming treatment is executed with the bubble adhering parts as non-electrodeposition parts. The electroforming shell K having ruggedness on the surface is thus formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a manufacturing method capable of easily providing an uneven shape on a metal deposition surface side when a slush mold is formed by electroforming.

[0002]

2. Description of the Related Art Conventionally, a resin sheet used for an instrument panel which is an interior part of an automobile, a door trim or the like has a large and complicated shape, and it is necessary to form a grain pattern or the like. Therefore, it may be formed by slush molding.

In such a slush molding method, it is necessary to heat the mold. Generally, the back side of the mold (the side opposite to the molding surface) is heated with a burner or far infrared rays, or in a heating furnace. However, in such a heating method, heating is not sufficient in a region far from the heat source, and gelation of plastisol is insufficient, which causes a defect in the skin material. In some cases, a defect countermeasure may be taken to increase heating efficiency by providing an uneven shape on the back side to increase the heating area.

For this reason, for example, when it is attempted to give unevenness to the metal deposition surface by electroforming, first, electroforming is carried out in an ordinary electrolytic bath to form an electroformed shell of a lower layer having a smooth metal deposition surface,
After that, it is necessary to perform electroforming in another electrolytic bath to form an electroformed shell of a porous upper layer so as to give an uneven shape to the metal deposition surface.

[0005]

However, in order to form the electroformed shell in two layers, two electroforming tanks are required, and the process is complicated and the manufacturing cost is high. . Further, by forming two layers, a lower layer and an upper layer, under different electroforming conditions, there is a problem of delamination due to the difference in internal stress generated in each layer during heating.

[0006]

In order to solve the above problems, the present invention forms a conductive layer on the surface of a model, immerses the model in an electrolyte solution containing no surfactant, and then uses a bubble suppressing means. The formation of an electroformed shell of a specified thickness while suppressing the adhesion of bubbles to the model, and when the specified thickness is obtained, the operation of the bubble suppression means is stopped and the bubbles are adhered to the metal deposition surface. The adhered part was electroformed as a non-electrodeposited part.

[0007]

By performing electroforming with an electrolyte solution containing no surfactant, bubbles such as hydrogen gas produced by electrolysis of water in the electrolyte solution are likely to adhere to the model. Therefore, for example, an ultrasonic wave generator, or an electroforming process is performed while suppressing the adhesion of bubbles by a bubble suppressing means such as a vibrator, and the operation of the bubble suppressing means is stopped from the time when a predetermined thickness is obtained, and the positive action is taken. When the electroforming process is continued by generating bubbles in the non-electrodeposited part with the bubble adhering part, the electroforming shell in which the lower layer is smooth and the upper layer is porous, that is, the metal deposition surface is uneven is formed by one electroforming process. I can.

[0008]

EXAMPLE An example of a method for manufacturing a slush mold according to the present invention will be described with reference to the process chart of FIG.

According to the present invention, the molding surface of the slush mold is
This is an electroforming method capable of easily imparting a concavo-convex shape for enhancing thermal efficiency. First, as shown in FIG. 1 (a), for example, the surface of a non-conductive model M such as an epoxy resin is formed. A conductive layer E is formed by applying a silver plating solution e or the like.

Next, as shown in (b), the model M is immersed in the electrolytic solution A. The electrolytic solution A is a nickel sulfamate bath in which boric acid is added to nickel sulfamate, and the nickel ion concentration is 250 to 400, for example.
The ratio of g / l and boric acid was 30 to 40 g / l, and no surfactant was added. The pH is 4.0 to 4.2,
The liquid temperature is 43 to 48 ° C.

An electroforming tank F containing the electrolytic solution A
A large number of ultrasonic wave transmitters W as a bubble suppressing means are provided around the circumference of.

Then, a nickel plate N connected to an anode is put in this electrolytic solution A, nickel electroforming is performed at a current density of 2 A / dm ² with the model M side as a cathode, and the ultrasonic wave transmitter W It emits ultrasonic waves with a frequency of 20 to 25 Hz.

That is, since the electrolytic solution A does not contain the surfactant as described above, the bubbles of hydrogen gas generated by the electrolysis of water adhere to the surface of the model M only by electroforming. By using the ultrasonic waves having the above frequencies, adhesion of bubbles to the surface of the model M is suppressed.

The bubble suppressing means may be means for stirring the electrolytic solution A in the electroforming tank F, or the model M or the electrolytic solution A may be vibrated by a vibration transmitter.

When the thickness of the electroformed shell Ko becomes about 3 mm as shown in (c) by the electroforming treatment as described above,
The operation of the ultrasonic transmitter W is stopped, and the electroforming treatment is continued in the same electrolytic solution A.

Therefore, the bubble B, which has been suppressed by ultrasonic waves, adheres to the surface of the electroformed shell Ko of the model M, and the part to which the bubble B adheres becomes a non-electrodeposition part, and the remaining part is electrodeposited. grow up. The size of the bubble B can be controlled by changing the electroforming conditions.

The lower layer having a smooth deposition surface and the upper layer having a porous deposition surface are integrally formed by such an electroforming method to form an electroformed shell K having an uneven metal deposition surface. As shown in (d), the shell K is separated from the model M and taken out.

Since this electroformed shell K is formed under the same electroforming conditions using the same electrolytic solution A, no difference in internal stress occurs even when heated, and delamination does not occur.

Further, the process is simplified and the working time can be shortened.

In the mold formed by the method of the present invention, if the backup material is laminated on the metal depositing surface side by utilizing the unevenness of the metal depositing surface, the concavo-convex shape makes it easier to bite with the backup material. Since it is possible to obtain a strong mold that is improved and does not cause peeling or the like, it can be used not only for slush molding but also for molds such as compression molding and injection molding.

[0021]

As described above, according to the method for producing a slush mold of the present invention, electroforming is performed with an electrolyte solution containing no surfactant, and at first, the adhesion of bubbles is prevented by a bubble suppressing means such as an ultrasonic transmitter. Perform electroforming while suppressing, and stop the operation of the bubble suppression means from the time when a predetermined thickness is obtained to positively adhere bubbles, and continue electroforming with the bubble adhered portion as the non-electrodeposited portion. Therefore, the electroformed shell having an uneven surface can be formed by one electroforming process using one electrolytic solution. Therefore, the manufacturing cost can be kept low, and defects such as delamination can be suppressed. The surface area is increased by the unevenness, and the heating efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a process diagram of the manufacturing method of the present invention.

[Explanation of symbols]

 B air bubble E conductive layer Ko electroformed shell of predetermined thickness K electroformed shell M model W ultrasonic wave transmitter

Claims (1)

[Claims] 1. A step of forming a conductive layer on a surface of a model,
After immersing this model in an electrolyte solution containing no surfactant, a step of forming an electroformed shell of a predetermined thickness while suppressing the adhesion of bubbles to the model by the bubble suppressing means, and a predetermined thickness can be obtained. At this point, the operation of the bubble suppression means is stopped, the bubbles are attached to the metal deposition surface, and the electroforming process is continued with the bubble-attached portion as the non-electrodeposition portion, and the step of separating the electroformed shell from the model. Slush mold manufacturing method.