Magnetic Peripherals Inc.

Seagate Technology Incorporated

Alan G Kracke

Douglas J Hennenfent

Allan L Holmstrand

Gregory S Mowry

Beat G Keel

Tuan P Tran

Phillip E Gorka

Brian D Strayer

A system for lapping a magnetoresistive (MR) sensor on a slider to a proper height is disclosed. The system comprises simultaneously lapping the MR lap monitor and the MR sensor positioned on the slider until a resistance of a variable resistor located within the MR lap monitor is approximately equal to a resistance of a target resistor located within the MR lap monitor. During the lapping process, a reference resistor located within the lap monitor is compared to both the variable and target resistors to prevent a lapping failure. In one preferred embodiment, the reference, target, and variable resistors are formed from a ferromagnetic metal alloy. The MR lap monitor and the MR sensor are lapped until a height of the ferromagnetic metal alloy forming the variable resistor is approximately equal to a height of the ferromagnetic metal alloy forming the target resistor.

MR head lap monitor resistors

Method of lapping MR. sensors

A method and article of manufacture allows great accuracy in machining the edge of a face on a prism to a predetermined position respective a feature carried on the face and formed by deposition of insulating material. The preferred application for this invention is in accurately machining the transducing surface of a disk memory transducer assembly so that the throat height of the thin-film head carried on an end face of the assembly has a precise value.

Machining sensor

A method of calibrating an analog machining sensor of the varying resistance type which has been deposited on a surface involves depositing adjacent it with great positional accuracy relative to a feature on the surface, discrete machining sensors. As machining takes place, the discrete sensor's continuities are successively broken as the analog sensor's height is reduced and its resistance increased. Measuring the resistance of the analog sensor at the time each discrete sensor breaks yields values from which the position of the analog sensor's machined edge can be very accurately related to the position of the feature on the surface.

Method for calibrating a machining sensor

Apparatus for precisely machining the surface of a workpiece comprises a rotating plate with a flat, horizontal abrasive-laden surface against which the workpiece surface is forced by gravity. The workpiece is carried on the free end of an arm pivotably supported remote from the end of the arm carrying the workpiece. Loading of the workpiece work surface can be varied by shifting weights along the length of the arm or transverse to the length of the arm. The workpiece itself can comprise a bar on which several magnetic transducing heads have been deposited. Machining the workpiece surface to a preferred position accurately defines a dimension of choice, such as the throat height of these transducers.

Precision lapping system

A workpiece carrier includes a flat support surface to which a workpiece is attached by bonding. The carrier includes means for bending the carrier support surface so that it becomes concave. When dealing with a relatively flexible workpiece, one can cause the workpiece's surface to be machined to attain a convex shape by bending the support surface of the carrier concavely, and then bonding the workpiece attachment surface to the carrier while the carrier support surface is concavely bent. Allowing the carrier's support surface to assume a less concave shape then imparts a convex shape to the surface of the workpiece to be machined.

Method for attaching a workpiece to a workpiece carrier

A method for use with an article of manufacture allows great accuracy in machining the edge of a face on a prism to a predetermined position respective a feature carried on the face and formed by deposition of insulating material. The preferred application for this invention is in accurately machining the transducing surface of a disk memory transducer assembly so that the throat height of the thin-film head carried on an end face of the assembly has a precise value.

Method for using a machining sensor

A workpiece carrier has a support bar centrally supported at one end of a stem portion. The stem is carried at its opposite end on a base. Columns are interposed between the ends of the support bar and the base. Heat is applied to the columns, preferably by resistive heating elements, to heat them and cause their thermal expansion, causing the support bar ends to be bent away from the base. A relatively flexible workpiece which has been bonded to the support arms on a surface facing away from the base will undergo the same bend.

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Minnetonka, MN, United States of America

Alan G Kracke