EP0201587A1 - Curseur avec bossage antiadherence - Google Patents

Curseur avec bossage antiadherence

Info

Publication number
EP0201587A1
EP0201587A1 EP19850905986 EP85905986A EP0201587A1 EP 0201587 A1 EP0201587 A1 EP 0201587A1 EP 19850905986 EP19850905986 EP 19850905986 EP 85905986 A EP85905986 A EP 85905986A EP 0201587 A1 EP0201587 A1 EP 0201587A1
Authority
EP
European Patent Office
Prior art keywords
slider
recited
boss
combination
piezo
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP19850905986
Other languages
German (de)
English (en)
Inventor
Raju S. Ananth
Michael Verdone
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Memorex Corp
Original Assignee
Memorex Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Memorex Corp filed Critical Memorex Corp
Publication of EP0201587A1 publication Critical patent/EP0201587A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/48—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed
    • G11B5/58—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed with provision for moving the head for the purpose of maintaining alignment of the head relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
    • G11B5/60—Fluid-dynamic spacing of heads from record-carriers
    • G11B5/6005—Specially adapted for spacing from a rotating disc using a fluid cushion
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/48—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed
    • G11B5/54—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed with provision for moving the head into or out of its operative position or across tracks

Definitions

  • This invention relates to high capacity magnetic recording discs and more particularly to improved magnetic head sliders therefor.
  • Stiction forces can be undesirably large and counter-productive. especially under the "sudden start" conditions usually desired — e.g., overloading the disc-rotating motor — [they can lead to damage to the slider and/or to the disc surface] .
  • Stiction can commonly induce a transfer of disc-material onto the slider rails; at times causing a flying slider to crash into the disc and render it useless.
  • lube is believed necessary — e.g., to prevent a slider from prematurely “gouging” or otherwise marring or digging-into the disc surface, and soon "crashing".
  • Conventional sliders e.g., 3680 Memorex DD
  • 50 A° film of lube are expected to have a useful life of about 10,000 stop-start cycles (cf. a contact start-stop test is widely accepted as a measure of media integrity) .
  • "Low-lube" conditions reduce this to the order of a mere 1,000 cycles; (unacceptable in the industry) .
  • FIG. 1 is a schematic elevation of a representative slider embodiment provided with a boss means as shown parked on a magnetic recording disc, while FIG. 2 is a plan view, FIG. 3 a side view, and FIG. 4 an end-view of this slider;
  • FIGS. 1A, IB are respective plan and side views of a related embodiment;
  • FIG. 5 is a plan view of a related 3-boss embodiment;
  • FIG. 6 is a plan view of a related 2-rail embodiment
  • FIGS. 7 and 8 are respective plan and side views of a related "medially-mounted" boss embodiment
  • FIGS. 9-11 are respective end, plan, and side views of a related piezo-boss embodiment
  • FIG. 12 is a plan view of an embodiment like that of FIG. 6 where the bosses are deformed by lapping or cold-worked;
  • FIGS. 13, 14, 16 and 16 represent plots, for certain embodiments, of "particle count” vs. "stop-start test time”. DESCRIPTION OF PREFERRED EMBODIMENTS
  • FIGS. 1-4 schematically illustrate a magnetic recording slider SL constructed and improved to include boss means according to principles of this invention.
  • the slider, and related means discussed herein, will generally be understood as constructed and operating as presently known in the art, except where otherwise specified; the materials, methods, and devices and apparatus being implemented by known expedients according to present good practice.
  • FIG. 1 depicts a conventional slider SL-I resting on an associated magnetic recording disc with a protruding "boss means", or metal slug B, raising the forward end of the slider off the disc surface.
  • slider SL-I will be understood as a relatively conventional three-rail
  • Winchester slider e.g., of the type used with a high speed disc drive, such as the Memorex 3650.
  • the slider is understood to carry thin film transducers tf (FIG. 4) , mounted at, or adjacent, its trailing edge TE as known in the art.
  • the three slider rails A., A ⁇ , A_ may be the order of 0.145 inch wide and include conventional ramp sections r, , r 2 , r.., respectively, disposed forward of their leading edge portions.
  • the disc-confronting faces of the rails define a prescribed "flight-plane" f f (see FIG. 4) .
  • Boss B will be understood as a tiny protrusion (e.g., relatively cylindrical or rectangular) projecting about 6 micro-inches below this "flight-plane” — cf. below the leading portion of the middle rail A_ (see FIG. 4) , preferably just aft of the associated ramp portion r 2 « Workers will recognize that so attaching a boss means “protuberance” relatively centrally off the forward portion of the slider will provide a “bias pitch” when the slider is at rest [on the stationary disc] — and of course will drastically reduce the contact area between slider and disc.
  • the slider faces are very, very smooth and flat — as is the disk surface and lube film thereon — and it is this interfacial contact of smooth flat surfaces that gives rise to "stiction”] . So providing a protuberance will, in turn, reduce (and can all but eliminate) the potential "stiction" force due to extreme flat conditions of the interface (note that slider SL-I now rests only on the boss and its trailing edge TE, rather than on the entire lengths of its slider rail faces) .
  • the boss B will preferably protrude only-barely beyond the slider level (e.g., a few micro-inches — preferably about 6u" — below flight plane f f in
  • FIG. 4 For instance, just enough to induce a fast efficient lift-off when the disc is suddenly rotated, yet not enough to interfere with air flow along the slider rails while they fly just above the disc.
  • a 6 micro-inch protrusion distance was settled-upon as a compromise between optimum head flying attitude (cf "bias”) and a stable rest configuration.
  • alumina (A1 2 0,) is a relatively non-preferred boss material since it is found relatively too soft when deposited in the amorphous state [e.g., surviving for only 4-5K cycles in a stop- start test] . And, while it is presumably quite a bit harder in the crystalline state, the heating necessary to induce crystallinity (in situ) is believed potentially harmful to the- transducer on the slider ' .
  • a “stop-start test” involves placing a slider in operating relation with a magnetic recording disc and stopping and starting the disc repeatedly- to cause the slider to "take off” and “land” under conditions simulating actual use.
  • the "survivability" of a slider-disc combination is adjudged according to the number of such stop-start cycles that can be run before significant degradation occurs, especially a "crash” or other catastrophic failure.
  • This stop-start test (summarized in FIG. 13) is instructive. Note that during the first six to twelve hours a relatively high particle count [using a commercial grade particle counter — of 0.3 - 0.5 micron] was experienced — (cf. FIG. 13, e.g., peak at about 4 hours) . This is rather normal and is believed to result from a "burnishing" of the peaks and asperities on the disc by the slider as it skids over the disc » surface during take off and landing.
  • This early lift-off will also be desirable to more quickly bring the slider into a smooth, laminar-flow flight mode, reducing turbulence and noise during lift-off and generally affording better air bearing performance [allowing one to shorten the take off zones and thus increase available bit space on the disc and increase disc life] .
  • workers will highly value a slider allowing earlier lift-off (at lower disc rpm) .
  • This embodiment was also surprisingly superior under "low lube" (“thin lube”) conditions, e.g., surviving 10,000 start-stops on a "depleted” lube thickness [about 20 A° applied] , while generating relatively less than the normal number of "particles" ( “macro-particles" about a certain size; see FIG. 15 discussed below) .
  • "thin lube” "thin lube”
  • FIGS. 1A, IB, 14, 15 are LTERNATE EMBODIMENTs.
  • FIGS. 1A, IB show a slider SL-II, replicating the slider of FIGS. 1-4 [e.g., with the same or like slider] with a similar boss B' deposited along the middle slider rail A' 2 just aft of its associated ramp r ⁇ ' , except that, after completion, the middle rail A.,' is etched-away somewhat (as indicated along plane R-g in FIG. IB) to essentially remove it as an air bearing surface.
  • slider performance e.g., aerodynamics, etc.
  • slider performance during stop-start testing is superior (like that of the embodiment of FIGS. 1-4).
  • One such is summarized in the plot of FIG. 14 [conditions and presumptions the same as those mentioned for FIG. 13 above, etc.] with the so-improved slider being run over a normally lubricated [55 A° average depth] disc of the type used in Memorex 3680 disc drives.
  • FIG. 5 j f Slider SL-III in FIG. 5 represents another embodiment; essentially the same as SL-I in FIGS. 1-4, except that three bosses, rather than one, are applied [each on a respective rail, just aft of a respective slider ramp, as with boss B SL-I] all being identical in size and construction of course.
  • This embodiment will perform essentially like SL-I except that, with the added boss means at the front, a "higher pitch" slider results — something that is desired in certain instances.
  • FIG. 6 FOURTH EMBODIMENT
  • FIG. 5 The embodiment of FIG. 5 (SL-III) is essentially replicated for a two-rail slider SL-IV as seen in FIG. 6, with each (identical) boss protruding about 6 micro-inches (beyond "flight-plane") and being deposited on a respective rail (each rail about 0.0167 inch wide), just aft of its respective ramp as before.
  • FIGS. 7, 8 the results were essentially as in the first embodiment SL-I. —FIFTH EMBODIMENT, FIGS. 7, 8:
  • a single elongate boss means, or slug B-V is here deposited midway between the rails and just aft of the ramp zone. This slug B-V is thus deposited on the medial ("throat") surface B between the rails, preferably being deposited in the fashion of those in the foregoing embodiments.
  • the two-rail embodiment of FIG. 6 is replicated in FIG. 12 as modified slider SL-VI, except that, here, instead of the (2) bosses being deposited, they are "cold worked", or shaped during lapping, into an appropriate "boss site” portion of the slider rails, as workers in the art will understand.
  • well-known techniques are feasible here — e.g., as a “roughening process”, understood as raising "bumps” ( micro-roughening) on the order of about 6 micro-inches above the normal slider surface.
  • a “roughening process” understood as raising "bumps” ( micro-roughening) on the order of about 6 micro-inches above the normal slider surface.
  • one may readily gouge-up protrusions on the order of 50 A° above such a (slider) surface, as workers know.
  • Such protrusions can be surprisingly effective as "multiple boss means", and appear to present no adverse side-effects (even during the brief contact with the disc during landing) .
  • FIGS. 9-11 In FIGS. 9-11, another alternate embodiment
  • SL-VII is produced by essentially replicating embodiment 'SL-V of FIGS. 7 and 8, but replacing slug B-V with a "piezo-slug" PRON of relatively foreshortened height, i.e., Pionat is just tall enough, or almost so, to intercept the "flight-plane" A A of the slider rail faces (air bearing surfaces ABS — like plane f f of FIG. 4) , yet not quite enough to project therebeyond — being about
  • element P __ will "self-elongate” enough to intercept and cross the flight-plane A A (e.g., extend
  • boss P __j will be selectively thrust out to protrude like the preceding boss means, and to yield the same "protruding boss" effects during a selected “boss mode" (as with the prior embodiments, but doing so only selectively, and only when energized, as known by those skilled in the art — i.e., functioning as a "selectively-protruded boss means") .
  • this technique will entail embedding a small piezo-element Pz at the center of the slider, between the two co-planar air bearing surfaces [rail faces ABS] and providing selective energizing piezo-power therefor.
  • this protruding piezo-boss may be expected to radically reduce slider- disc contact as to alleviate, if not entirely eliminate, problematic stiction forces acting between the ABS surfaces and the disc lubricant.
  • energizing power to the piezo element P l.i may be turned-off, contracting the piezo-element to its non-protruding length.
  • a "bias pitch" of various selectible degrees can be provided when the disc is stationary merely by appropriately energizing the piezo-boss ("piezo-slug") to induce a desired associated elongation. And, the element may be energized before the disc comes to rest (that is, during landing) so that there will be sliding contact only between P and the slider's trailing edge. Then, if the piezo P concentrate is elongated before the disc stops, it can help reduce excess contact force (evidently increased hydrodynamic pressure under the piezo-boss "cushions" of the slider) .
  • piezo-boss Such incorporation of a “piezo-boss” element, appropriately energized and located, is a simple technique to implement.
  • the piezo element being a tiny capacitance device, will consume negligible power (e.g., the voltage necessary for such operation should be in the range of 20-35 volts for an elongation of the order of a few micro-inches) .
  • negligible power e.g., the voltage necessary for such operation should be in the range of 20-35 volts for an elongation of the order of a few micro-inches
  • This embodiment in principle, yields results like the embodiment of FIG. 7, with the added advantage that debris-generation is much less likely.
  • boss like B in SL-I or the like and provide heating means to heat the boss enough to elongate it as required [as with the piezo-boss] from a condition of coincidence with the slider plane to about 5-10 micro-inches therebeyond [e.g., one can do this with an embedded coil and selectively applying current] .
  • Workers may also contemplate alternative ways of depositing such a boss such as by plating, or vapor depositing and etching - back, or vacuum deposition, flame coating, ion-gun deposition (local) oxidation, etc., as known in the art.
  • a plastic boss would be preferable, e.g., a teflon (tetrafluoroethylene) boss that has a relatively low coefficient of friction. Surprisingly, this doesn't appear to be necessary or important — although one might deposit a plastic (like teflon) by providing a suitable "adhesion-site" [e.g., epoxy bond a teflon substrate in place of the above bosses and thereafter cold working, or deposing a super-layer of teflon thereon — e.g., by vacuum evaporating teflon stock so it deposits preferentially onto this "teflon substrate"] .
  • a suitable "adhesion-site” e.g., epoxy bond a teflon substrate in place of the above bosses and thereafter cold working, or deposing a super-layer of teflon thereon — e.g., by vacuum evaporating
  • the present invention is applicable for providing "anti-stiction" boss means (or boss-bias means) to reduce related forces between any such smooth surfaces, especially to reduce relative friction therebetween, whether the surfaces are lubricated or not.
  • "anti-stiction" boss means or boss-bias means

Landscapes

  • Adjustment Of The Magnetic Head Position Track Following On Tapes (AREA)

Abstract

Les modes de réalisation les plus caractéristiques comprennent un curseur (SL) d'enregistrement magnétique dont la face servant à l'enregistrement est caractérisée par deux ou trois guides (A) dont les forces d'adhérence sont neutralisées par des bossages (B) sur un ou plusieurs guides (A), ou entre ceux-ci; l'invention concerne aussi le procédé de fabrication d'un tel curseur.
EP19850905986 1984-11-13 1985-11-12 Curseur avec bossage antiadherence Withdrawn EP0201587A1 (fr)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
US67045184A 1984-11-13 1984-11-13
US67046884A 1984-11-13 1984-11-13
US67026584A 1984-11-13 1984-11-13
US670265 1984-11-13
US670451 1984-11-13
US670468 1984-11-13

Publications (1)

Publication Number Publication Date
EP0201587A1 true EP0201587A1 (fr) 1986-11-20

Family

ID=27418207

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19850905986 Withdrawn EP0201587A1 (fr) 1984-11-13 1985-11-12 Curseur avec bossage antiadherence

Country Status (4)

Country Link
EP (1) EP0201587A1 (fr)
AU (1) AU5095185A (fr)
CA (1) CA1265867A (fr)
WO (1) WO1986003048A1 (fr)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4833556A (en) * 1987-12-22 1989-05-23 Eastman Kodak Company Low drag stabilizer device for stabilizing the interface between a transducer and a moving medium
US5285337A (en) * 1992-04-30 1994-02-08 International Business Machines Corporation Liquid-bearing data recording disk file with transducer carrier having support struts
US5418667A (en) * 1993-08-03 1995-05-23 International Business Machines Corporation Slider with transverse ridge sections supporting air-bearing pads and disk drive incorporating the slider
US6330131B1 (en) * 1993-09-17 2001-12-11 Read-Rite Corporation Reduced stiction air bearing slider
US6587308B2 (en) 1999-01-29 2003-07-01 Seagate Technology, Llc Disc head slider having profiled convergent channel features
US6504682B1 (en) * 1999-12-02 2003-01-07 Seagate Technology Llc Disc head slider having recessed, channeled rails for reduced stiction
US6989965B2 (en) 2002-11-07 2006-01-24 Seagate Technology Llc Head slider having tilted protrusions for ramp load-unload applications

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3573768A (en) * 1967-10-20 1971-04-06 Singer Co Stepped magnetic head with offset biasing
JPS51128511A (en) * 1975-04-30 1976-11-09 Canon Inc Magnetic sheet unit
JPS56107363A (en) * 1980-01-31 1981-08-26 Nec Corp Floating type magnetic head
JPS57210479A (en) * 1981-06-22 1982-12-24 Hitachi Ltd Floating type magnetic head
EP0090055B1 (fr) * 1982-03-25 1985-11-21 Ibm Deutschland Gmbh Patin pour tête magnétique en matériau céramique

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO8603048A1 *

Also Published As

Publication number Publication date
WO1986003048A1 (fr) 1986-05-22
CA1265867A (fr) 1990-02-13
AU5095185A (en) 1986-06-03

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