Browse Prior Art Database

Hub Centering With Liquid Adhesive

IP.com Disclosure Number: IPCOM000036908D
Original Publication Date: 1989-Nov-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 2 page(s) / 24K

Publishing Venue

IBM

Related People

Guidotti, EP: AUTHOR [+3]

Abstract

This article discusses a simple way to attach a hub to an optical disk with a minimum amount of tooling and also keeping the radial runout low.

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Hub Centering With Liquid Adhesive

This article discusses a simple way to attach a hub to an optical disk with a minimum amount of tooling and also keeping the radial runout low.

During the assembly process of the fabrication of an optical disk the cover substrate and hub are attached to the medium substrate with a thermally curable adhesive by the "free flow" method. The "free flow" method is a process whereby a pre-measured amount of adhesive is applied to the mating parts as a circumferential bead and the adhesive flows to its final position and then cures. This process also requires a minimum amount of tooling and fixturing. One of the major problems of the assembly process was trying to keep the radial runout low. The following describes a method to achieve this.

Since the metal hub expands more than the glass substrates during thermal cure and due to fabrication tolerances, the clearance between the hub and glass is too great for the hub to do a sufficient job of locating with a low radial runout. In order to reduce the radial runout and increase the yield, a bead of adhesive is placed on the outside surface of the hub, as shown, and then the hub is placed in the substrates. Because the adhesive is a viscous liquid and due to surface tension between the hub, adhesive and glass, it centers itself in the substrates. The adhesive also makes up for the clearance between the parts. This method is suitable for both single-sided and double-sided disks.

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