Browse Prior Art Database

Throat Height Measurement in Inductive Heads

IP.com Disclosure Number: IPCOM000045775D
Original Publication Date: 1983-Apr-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 46K

Publishing Venue

IBM

Related People

Hurd, CD: AUTHOR [+2]

Abstract

A generally sawtooth pattern of different color, nonmagnetic material is placed in the head gap of an inductive head. During grinding, the ever-changing dimension of these different colors allows one to monitor grinding. Subsequently, after extended use of the head, this same color difference can be used to determine if the head should be replaced.

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Throat Height Measurement in Inductive Heads

A generally sawtooth pattern of different color, nonmagnetic material is placed in the head gap of an inductive head. During grinding, the ever-changing dimension of these different colors allows one to monitor grinding. Subsequently, after extended use of the head, this same color difference can be used to determine if the head should be replaced.

In Fig. 1, a head' s generally C-shaped magnetic core is made up of a pair of pole pieces 10 and 11 which are spaced to define a transducing gap 12. This gap is filled by a nonmagnetic filler material, as is conventional. Pole piece 11 is shown as carrying this filler material in the form of a sawtooth-like pattern whose portions 13 are of a different color than portion 14. A dotted line 15 shows the finished dimension of the head. That is, all of the material above dotted line 15 is removed during head manufacture, leaving a throat height 16.

Fig. 2 shows pattern 13, 14 in greater detail. During lapping of the head, dimensions "a" and "b" are optically monitored. When the two dimensions are equal, as shown, plane 15 has been reached and lapping stops.

Later on, during use of the head, its dimension "a" decreases as dimension "b" increases. One can observe these changing-color dimensions and determine when the head should be replaced.

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