GB2306906A

GB2306906A - Fixing method

Info

Publication number: GB2306906A
Application number: GB9701105A
Authority: GB
Inventors: Masashi Shiraishi; Masaharu Ishizuka; Noboru Shinohara
Original assignee: TDK Corp
Current assignee: TDK Corp
Priority date: 1995-01-24
Filing date: 1996-01-19
Publication date: 1997-05-14
Anticipated expiration: 2016-01-19
Also published as: GB9707058D0; GB2309925B; GB9701105D0; GB2306906B; GB2309925A

Abstract

A method for fixing members (71,73) together includes a step of forming a resister pattern (74) on one of the members adjacent the adhesive (72), inserting a thermosetting adhesive (72) between the members to be bonded with each other, and a step of flowing a current through the resister (74) so that the adhesive is cured due to Joule effect caused by the current flowing through the resister (74).

Description

FIXING METHOD AND POSITIONING TOOL The present invention relates to a method for fixing members. to a method for fixing a floating magnetic head slider used for example in a hard disk device with a slider support member. and to a positioning tool for fixing a magnetic head slider with a slider support member.

There are several known methods for fixing a floating magnetic head slider to its support member such as a suspension. These are for example (1) a method for bonding the slicer to the suspension by means of a thermosetting adhesive, (2) a method for bonding the slider to the suspension by means of an Ultra Violet (UV) curing adhesive, (3) a method for bonding the slider to the suspension by means of both a thermosetting adhesive and a UV curing adhesive, and (4) a method for bonding the slider to the suspension by reflow soldering or welding.

(1) A bonding method using a thermally cured adhesive is method is described for example in Japanese Patent Unexamined Publication No.6(1994)-60346. As shown in Fig. 1, a magnetic head slider 11 and a suspension 13 on which a thermosetting adhesive 12 is supplied are mounted on a positioning tool for bonding 10. Then, the slider 11 and the suspension 13 together with the tool 10 are heated in an oven to cure the supplied thermosetting adhesive 12 and thus to bond the slider 11 with the suspension 13.In Fig. 1, furthermore, a reference numeral 14 denotes a guide of the slider 11, 15 denotes a press member for pressing the suspension 13 to the slider 11, 16 denotes its press spring, 17 denotes a press member for pressing the suspension 13, 18 denotes its press spring, 19a denotes an alignment pin inserted into a reference hole of the suspension 13, and 19b denotes an alignment pin inserted into an attachment hole of the suspension 13.

Bonding of the slider 11 to the suspension 13 by means of the thermally cured adhesive 12 will result a sufficient bonding strength even if the adhesive area is small. However, according to the above-mentioned prior art, since the positioning tools are heated in the oven together with the sliders and the suspensions during curing process of the adhesive, a large number of the positioning tools are necessary depending upon the number of the magnetic heads to be manufactured. Therefore, it is difficult to keep the alignment precision of all the positioning tools in a desired level because of the dispersion of the many positioning tools.

Furthermore, as the positioning tools are affected to heating in the oven, their alignment precision will be thermally deteriorated. Accordingly, it has been quite difficult to manage the alignment precision of the positioning tools to keep in a high level. In addition, since not only the slider and the suspension but also the positioning tool are heated, their heat capacity will be increased causing their heating time to lengthen and their heating conditions are limited to the minimum heat-resisting characteristics of the positioning tool.

(2) A bonding method using UV curing adhesive According to this method described for example in Japanese Patent Unexamined Publication No.5(1993)-325460, a magnetic head slider on which a UV curing adhesive is supplied is superposed at a predetermined position on a suspension using a positioning tool, and then a UV light is radiated thereto so as to cure the supplied UV curing adhesive.

Bonding of the slider to the suspension by means of the UV curing adhesive can prevent alignment precision of the positioning tool from being deviated due to thermal stress because the tool itself is not heated in an oven. However, according to this method, since a part of the adhesive particularly the adhesive between the slider and a flexure of the suspension receives no radiation of the UV light and thus never cure, a sufficient bonding strength cannot be obtained only by the radiation of the UV. Furthermore, in case of small bonding area, it is difficult to expect a desired bonding strength by using only the UV curing adhesive.

In Japanese Patent Unexamined Publication No.5(1993)40927, it is described that the flexure is constituted by a UV transparent resin in order to reduce non-radiated area of the UV light. However, according to this method, it is necessary to use a flexure made of a specific material and also it is difficult to expect a sufficient bonding strength by using only the UV curing adhesive in case of small bonding area.

(3) A bonding method using both a thermosetting adhesive and a UV curing adhesive According to the method described for example in Japanese Patent Unexamined Publication No.6(1994)-60346, both of a thermosetting adhesive and a UV curing adhesive are simultaneously used for bonding a magnetic head slider with a suspension depending upon the respective curing conditions.

Namely, the thermosetting adhesive is used for bonding a part which is difficult to be radiated by the UV light, and the UV curing adhesive is used for the remaining bonding part.

However, using of two kinds of adhesive will result a low production efficiency. Furthermore, since the UV curing adhesive has inherent property of interrupting the cure of the thermosetting adhesive such as epoxy resin, these adhesives must be treated not to be mixed with each other causing the assembling process to be complicated.

(4) A bonding method by reflow soldering or welding In accordance with this method described for example in Japanese Patent Unexamined Publication No. 59(1984)-63058, a magnetic head slider is secured on a suspension by reflow soldering or by welding.

However, according to this method, all of the slider, the suspension and the positioning tool must have heatresisting characteristics against soldering or welding.

Furthermore, it is necessary to form electrodes for soldering or welding on adhering surfaces of the slider and the suspension.

British Patent Application No. 9601055.8 (Publication Number 2297284), from which this is divided, describes a method for fixing members which includes a step of inserting a conductive thermosetting adhesive between the members to be bonded with each other, and a step of flowing a current directly through the conductive thermosetting adhesive so that the adhesive is cured itself due to Joule effect caused by the current flowed through the adhesive, wherein said conductive thermosetting adhesive is made of an epoxy resin adhesive with a conductive filler.

According to the present invention, a method for fixing members includes a step of previously forming a resister pattern on at least one of the members to be bonded with each other, a step of inserting a thermosetting adhesive between the members, and a step of flowing a current through the resister pattern so that the thermosetting adhesive is cured due to Joule effect caused by the current flowed through the resister pattern.

Also, according to the present invention, a method for fixing a magnetic head slider with a slider support member includes a step of previously forming a resister pattern on at least one of the magnetic head slider and the slider support member to be bonded with each other, a step of inserting a thermosetting adhesive between the magnetic head slider and the slider support member, and a step of flowing a current through the resister pattern so that the thermosetting adhesive is cured due to Joule effect caused by the current flowed through the resister pattern.

Since the thermosetting adhesive is heated due to Joule effect by flowing a current through the resister pattern located on the bonding surface, only a local area existing the adhesive to be cured is heated, therefore, extremely effective curing of the epoxy resin can be expected. Thus, the curing process can be easily performed in a short time.

In assembling the magnetic head slider with its support member, it is preferred that the method further includes a step of mounting the magnetic head slider and the slider support member at a predetermined alignment position on a positioning tool for bonding, a step of temporally bonding the magnetic head slider with the slider support member by the above-mentioned current flowing step, a step of removing the temporally bonded magnetic head slider support member from the positioning tool, and a step of fully bonding the magnetic head slider with the slider support member by further curing the adhesive.

It is not necessary that the positioning tools are heated in the oven together with the sliders and the suspensions during curing process of the adhesive. Thus, a large number of the positioning tools are not necessary depending upon the number of the magnetic heads to be manufactured. Therefore, alignment precision of all the positioning tools can be kept in a desired level and can be prevented from being thermally deteriorated. Furthermore, since the thermosetting adhesive is used, a sufficient bonding strength can be expected at all bonding area.

Also, using only one kind of adhesive will result high production efficiency.

Preferably, the thermosetting adhesive is made of an epoxy resin adhesive.

An example of the present invention will now be described with reference to the accompanying drawing, in which Figure 1 schematically shows a constitution of a fixing method in accordance with the present invention.

In the embodiments of Figs. 2, 5 and 6 in our copending British Patent Application No. 9601055.8 (Publication Number 2297284), from which this is divided, the DC current for heating flows directly through the conductive adhesive. However, in this invention, as shown in Fig. 1, a non-conductive thermosetting adhesive 72 such as an epoxy resin adhesive is heated to cure by flowing a DC current through a resister pattern 74 formed previously on a bonding surface of a suspension 73.

As shown in the figure, the non-conductive thermosetting adhesive 72 is supplied on a bonding surface which is the opposite surface of the ABS (Air Baring Surface) of a magnetic head slider 71. The slider support member such as the suspension 73 with the resister pattern 74 on its bonding surface is superposed at a predetermined position on the slider 71. In a modification, the resister pattern may be formed on the bonding surface of the slider 71.

A DC power supply 79 for providing a continuous DC current is electrically connected between both ends 74a and 74b of the resister pattern 74. The DC power supply 79 is constituted by a power source with a regulator, which performs a constant voltage control when its load resistance is high and is switched into a constant current control when the load resistance lowers. Instead of the DC power supply, a pulse power supply for providing an intermittent pulse current may be used. In this case, a duty ratio will be for example 50%, a voltage to be applied will be 5 V and the pulse current will be limited to 2 A or less.

Since the epoxy resin adhesive 72 is locally heated and cured due to Joule effect by flowing current through the resister pattern 74 formed in contact with the adhesive, extremely effective curing of the epoxy resin can be expected. Thus, a short temporal bonding time can be attained.

Claims

1. A method for fixing members comprising the steps of: previously forming a resister pattern on at least one of the members to be bonded with each other; inserting a thermosetting adhesive between said members; and flowing a current through said resister pattern so that said thermosetting adhesive is cured due to Joule effect caused by the current flowed through the resister pattern.

2. The method as claimed in claim 1, wherein said method further comprising a step of detecting real temperature of said thermosetting adhesive, and wherein said flowing step includes a step of adjusting the current flowing through the thermosetting adhesive depending upon the detected real temperature.

3. The method as claimed in claim 1, wherein said thermosetting adhesive is made of an epoxy resin adhesive.

4. A method for fixing a magnetic head slider with a slider support member, said method comprising the steps of: previously forming a resister pattern on at least one of said magnetic head slider and said slider support member to be bonded with each other; inserting a thermosetting adhesive between the magnetic head slider and the slider support member; and flowing a current through said resister pattern so that said thermosetting adhesive is cured due to Joule effect caused by the current flowed through the resister pattern.

5 The method as claimed in claim 4, wherein said method further comprising a step of detecting real temperature of said thermosetting adhesive, and wherein said flowing step includes a step of adjusting the current flowing through the thermosetting adhesive depending upon the detected real temperature.

6. The method as claimed in claim 4, wherein said method further comprises the steps of: mounting the magnetic head slider and the slider support member at a predetermined alignment position on a positioning tool for bonding; temporally bonding the magnetic head slider with the slider support member by said current flowing step; removing the temporally bonded magnetic head slider and slider support member from the positioning tool; and fully bonding the magnetic head slider with the slider support member by further curing the adhesive.

7. The method as claimed in claim 4, wherein said thermosetting adhesive is made of an epoxy resin adhesive.

8. A method substantially as described with reference to Figure 1.

9. A positioning tool substantially as described with reference to Figure 1.