JPH05311451A - Dust proofing treatment for light alloy casting - Google Patents

Abstract

PURPOSE:To reduce dust in a magnetic disk device by preventing dedusting from a light alloy casting surface treated with an electroless nickel plating or the like. CONSTITUTION:In the magnetic disk device or the like which forms structural members by applying surface treated film such as the electroless nickel plating on the surface of the light alloy casting, the generation of dust from the surface of the light alloy casting is prevented by previously removing metallic fine pieces or fiber flocks by executing barrel working before applying the surface treated coating and in this state, applying the surface treated coating. A water jet cleaning can be used jointly with the barrel working.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a treatment method for preventing dust from the surface of a light alloy casting in an apparatus using a disk such as a magnetic disk as a recording medium.

[0002]

2. Description of the Related Art In a magnetic disk device used for data storage in an electronic computer system, it is necessary to reduce the flying height of a magnetic head with respect to a magnetic disk in order to increase the storage density as the storage capacity increases. On the other hand, reducing the flying height of the magnetic head makes it extremely easy to cause sliding when dust enters the magnetic disk. For this reason, recent magnetic disk devices have a structure in which a magnetic disk, a magnetic head, an electronic circuit, and a mechanical portion are housed in a container having a closed structure to prevent the intrusion of external dust. And as the material of the mechanism in this seal, weight reduction, economy,
From the viewpoint of performance, light alloy castings such as aluminum and magnesium are often used. These light alloy castings are subjected to electroless nickel plating coating after being machined to a predetermined size to prevent rust and galling on the casting surface.
It is incorporated into a magnetic disk device. As means for preventing dust generation from these castings, Japanese Patent Publication No. 2-167070 describes an electroless nickel plating coating after machining and a method for removing cutting oil from a casting cavity by immersion in a chromic acid solution. .
This is because electroless nickel plating removes metal particles and mold release agent on the casting surface in the etching process or prevents dust generation by coating, and further the cutting fluid that has penetrated into the casting cavity is immersed in a chromic acid solution for carbonization. At the same time, it is dissolved in the solution and removed to prevent dust generation.

[0003]

According to the above method,
For the removal of cast metal particles from the casting surface, which is a component of dust generated from the surface of cast alloys such as aluminum and magnesium, small ones are removed by etching process by electroless nickel plating, and large ones are removed. Is to be coated and prevented by plating.

However, when observing in detail the aluminum casting that has been actually plated, as shown in FIG. 5, the cast metal particles 1 that have fallen from the casting are connected to the casting surface 3 by the plating layer 2 or are half raised. A part where the plating layer 2 covers the semi-peeled fine piece 4 is found. When the casting having such a portion was impacted with a hammer or the like and the residual dust after cleaning was analyzed, aluminum cast metal particles 1 whose surface was covered with electroless nickel plating were detected. From this, in the case of a casting whose surface is simply covered with electroless nickel plating, the casting metal fine particles 1 fall off due to impact during the transportation of parts and the assembly process, resulting in dust and a magnetic head and a magnetic disk. There was a problem that caused sliding.

Further, the fiber scraps 5 attached to the casting surface 3 by the work gloves in the manufacturing process of the light alloy casting are not removed by the etching in the pre-plating step because the gloves are made of cotton, and are mechanically removed. However, since there is only a means for removing it by burning, the conventional method has a problem that it remains after the plating and becomes dust.

The present invention solves the problems of the prior art as described above, removes the cast metal particles 1, the lifted semi-debonded particles 4 and the fiber scraps 5 from the casting surface 3, and electroless nickel plating. It is an object of the present invention to provide a dustproof treatment method for light alloy castings, which can prevent the subsequent metal fine pieces 1 and 4 and fiber waste 5 from falling off.

[0007]

In order to achieve the above-mentioned object, the present invention relates to a magnetic disk or the like in which a surface treatment coating such as electroless nickel plating is applied to the surface of a light alloy casting to form a mechanical member. In an apparatus that uses a disk as a recording medium, barrel processing is performed before applying the surface treatment coating to remove metal particles and the like on the surface of the light alloy casting, and by applying the surface treatment coating in that state. The feature is that it is designed to prevent dust generation from the surface of the light alloy casting.

[0008]

According to the present invention, as described above, the metal fine particles 1 and the semi-exfoliated fine particles 4 and the fibers produced at the time of finishing the casting by performing the barrel processing before applying the surface treatment coating such as the electroless nickel plating. Since the scraps 5 and the like are removed in advance and a surface treatment coating such as electroless nickel plating is applied in that state, dust removal after the surface treatment coating such as plating can be reliably prevented.

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a process diagram showing a first embodiment of the dustproof treatment method according to the present invention.

As shown in FIG. 1, in this embodiment, a casting step (1), a barrel finishing step (2), a precision machining step (3), and an electroless nickel plating (surface treatment step).
(4) and. More specifically, it is as follows.

(1) Casting process: Casting is performed by a sand mold, a metal casting method, a die casting method, or the like, and the casting is subjected to necessary heat treatment, and finishes such as feeders, mold dividing surfaces, and degassing pin marks are made by a belt sander. Finally, finish the casting surface with a stainless steel yacht, zinc sailboat, aluminum sailboat, etc.

(2) Barrel finishing process: The light alloy casting is barrel finished before machining to prevent deformation. A wet vibration barrel was used for this barrel, and alumina media was used for 30 to 60 minutes.

Table 1 shows barrel conditions.

[0014]

[Table 1]

(3) Precision machining step: The light alloy casting, the surface of which is smoothed by the above (2), is machined to a predetermined size. As long as cleanliness is required and the shape does not change the size, deburring during machining is also used, and the same effect can be obtained by performing barrel finishing after (2) after machining. it can.

(4) Surface treatment step: The above light alloy casting is coated with electroless nickel plating. The thickness of the plating film is preferably about 10 μm in view of the strength of the coating film and the dimensional accuracy of the machined surface.

FIG. 6 shows the results of measuring the amount of dust generated from the surface of a light alloy casting, which was subjected to the dustproofing method of the present invention, on a casting shot with zinc shot by a dust monitor. Assuming that the case of processing and plating by the conventional method is 100, the product of the present invention has a value of 30 which is ⅓ or less, which is a significant dust reduction effect.

FIG. 2 shows (4) in order to remove dust adhering to the polishing powder and the light alloy casting in the barreling process.
This is a second embodiment in which (5) cleaning by water jet is added after electroless nickel plating.
As the condition for cleaning with water jet, if the water pressure is too strong, it may peel off, so the pressure is 90 kgf.
The processing time is about 5 minutes / cm ² , and the cleaning solution is preferably pure water warm water to prevent spots.

FIG. 3 is a process diagram showing a third embodiment using electrodeposition coating as the surface treatment process. Since the film thickness accuracy of electro-deposition coating is not good, the casting is (2) barrel processed
(3) Perform electrodeposition coating, and then (4) perform precision machining to cut only the required surface.

FIG. 4 is a process diagram showing a fourth embodiment using electrodeposition coating, and for the same reason as explained in FIG. 2,
An example in which (3) a water jet cleaning step is added after (2) barrel finishing and (4) electrodeposition coating is applied is shown.

Although the above embodiment has been described as applied to a magnetic disk device, the dustproof processing method of the present invention is not limited to a magnetic disk, but may be applied to an optical disk device or the like which also needs dustproofing. Can also be applied.

[0022]

As described above, according to the present invention, metal fine particles and semi-exfoliation which are produced at the time of finishing a casting by barreling before applying a surface treatment coating such as electroless nickel plating. Since the fine particles are removed in advance and the surface treatment coating is applied in that state, it is possible to prevent dust removal after the surface treatment coating such as plating and reduce the dust in the disk device.

[Brief description of drawings]

FIG. 1 is a process drawing showing a first embodiment of the present invention.

FIG. 2 is a process drawing showing a second embodiment of the present invention.

FIG. 3 is a process drawing showing a third embodiment of the present invention.

FIG. 4 is a process drawing showing a fourth embodiment of the present invention.

FIG. 5 is a schematic sectional view of a plating surface in a conventional method.

FIG. 6 is a comparison diagram of the number of generated dust between the conventional method and the method of the present invention.

[Explanation of symbols]

1 ... Light alloy cast particles, 2 ... Electroless nickel plating layer, 3
… Light alloy castings, 4… Casting semi-peeling particles, 5… Fiber scraps.

Front Page Continuation (72) Inventor Minoru Hasegawa 2880 Kozu, Odawara City, Kanagawa Stock Company Hitachi Ltd. Odawara Plant

Claims (1)

[Claims] 1. An apparatus using a disk, such as a magnetic disk, for forming a mechanism member by applying a surface treatment coating such as electroless nickel plating on the surface of a light alloy casting, before applying the surface treatment coating. By removing the metal particles on the surface of the light alloy casting by barrel processing, and applying the surface treatment coating in that state, it is possible to prevent dust emission from the surface of the light alloy casting. Dustproof treatment method for light alloy castings.