US4982065A
Expired / Lapsed
US
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Method of producing a core for magnetic head
Assignee: NGK Insulators Ltd
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Filing: 1989-08-29
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Granted: 1991-01-01
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Expires: 2009-08-29
Abstract
Abstract A core for magnetic head, which has a groove depth of at least 10 μm with a dimensional accuracy not lower than ±2 μm in the groove for defining the track of the core, can be obtained by subjecting a gapped bar made of ferrite and/or Sendust to a laser-induced etching wherein a laser beam having a focused beam diameter of not larger than 50 μm, preferably not larger than 20 μm, and a laser power P in a specified range is irradiated at a scanning speed V that is within a range between 2 μm/sec and 200 μm/sec and delimited by the laser power P, in a phosphoric acid or alkali metal hydroxide aqueous solution.
Inventors
- 👤 Hideto Sandaiji
- 👤 Fuminori Takeya
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 00:59
CPC Classifications
H; H01; H01F; H01F41/00; H01F41/02; H01F41/0206; B; B23; B23K; B23K26/00; B23K26/0093; B23K26/12; B23K26/1224; B23K26/36; B23K26/362; B23K26/364; C; C23; C23F; C23F1/00; C23F1/02; G; G11; G11B; G11B5/00; G11B5/127; G11B5/187; G11B5/1871
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
93 words
In a method of producing a core for magnetic head, wherein a track width of the core for magnetic head is defined by a laser machining, the improvement comprising machining by a laser-induced etching wherein a laser beam having a focused beam diameter of not larger than 50 μm and a power (P) of 50˜1,900 mW is irradiated, in a 10˜90 weight % phosphoric acid aqueous solution, at a scanning speed (V) in the range between 2 μm/sec and 200 μm/sec which scanning speed satisfies simultaneously both the following conditions: V≦0.31P+34 and V≦-0.14P+271.
Claim 2
Dependent Claim
93 words
In a method of producing a core for magnetic head, wherein a track width of the core for magnetic head is defined by a laser machining, the improvement comprising machining by a laser-induced etching wherein a laser beam having a focused beam diameter of not larger than 50 μm and a power (P) of 50˜1,900 mW is irradiated, in a 10˜90 weight % phosphoric acid aqueous solution, at a scanning speed (V) in the range between 2 μm/sec and 200 μm/sec which scanning speed satisfies simultaneously both the following conditions: V≦0.31P+34 and V≦-0.14P+271.
Claim 3
Dependent Claim
97 words
In a method of producing a core for magnetic head made of ferrite, wherein a track width of the core for magnetic head is defined by a laser machining, the improvement comprising machining by a laser-induced etching wherein a laser beam having a focused beam diameter of not larger than 20 μm and a power (P) of 50˜1,300 mW is irradiated, in a 5˜55 weight % alkali metal hydroxide aqueous solution, at a scanning speed (V) in the range between 2 μm/sec and 150 μm/sec which scanning speed satisfies simultaneously both the following conditions: V≦0.34P+13 and V≦-0.17P+217.
Claim 4
Dependent Claim
97 words
In a method of producing a core for magnetic head made of ferrite, wherein a track width of the core for magnetic head is defined by a laser machining, the improvement comprising machining by a laser-induced etching wherein a laser beam having a focused beam diameter of not larger than 20 μm and a power (P) of 50˜1,300 mW is irradiated, in a 5˜55 weight % alkali metal hydroxide aqueous solution, at a scanning speed (V) in the range between 2 μm/sec and 150 μm/sec which scanning speed satisfies simultaneously both the following conditions: V≦0.34P+13 and V≦-0.17P+217.
Claim 5
Dependent Claim
97 words
In a method of producing a core for magnetic head made of Sendust, wherein a track width of the core for magnetic head is defined by a laser machining, the improvement comprising machining by a laser-induced etching wherein a laser beam having a focused beam diameter of not larger than 20 μm and a power (P) of 50˜1,000 mW is irradiated, in a 5˜55 weight % alkali metal hydroxide aqueous solution, at a scanning speed (V) in the range between 2 μm/sec and 70 μm/sec which scanning speed satisfies simultaneously both the following conditions: V≦0.1P+10 and V≦-0.18P+180.
Claim 6
Dependent Claim
97 words
In a method of producing a core for magnetic head made of Sendust, wherein a track width of the core for magnetic head is defined by a laser machining, the improvement comprising machining by a laser-induced etching wherein a laser beam having a focused beam diameter of not larger than 20 μm and a power (P) of 50˜1,000 mW is irradiated, in a 5˜55 weight % alkali metal hydroxide aqueous solution, at a scanning speed (V) in the range between 2 μm/sec and 70 μm/sec which scanning speed satisfies simultaneously both the following conditions: V≦0.1P+10 and V≦-0.18P+180.
Claim 7
Dependent Claim
100 words
In a method of producing a composite core for magnetic head composed of ferrite and Sendust, wherein a track width of the core for magnetic head is defined by a laser machining, the improvement comprising machining by a laser-induced etching wherein a laser beam having a focused beam diameter of not larger than 20 μm and a power (P) of 50˜1,000 mW is irradiated, in a 5˜55 weight % alkali metal hydroxide aqueous solution, at a scanning speed (V) in the range between 2 μm/sec and 130 μm/sec which scanning speed satisfies simultaneously both the following conditions: V≦0.34P+13 and V≦-0.19P+190.
Claim 8
Dependent Claim
100 words
In a method of producing a composite core for magnetic head composed of ferrite and Sendust, wherein a track width of the core for magnetic head is defined by a laser machining, the improvement comprising machining by a laser-induced etching wherein a laser beam having a focused beam diameter of not larger than 20 μm and a power (P) of 50˜1,000 mW is irradiated, in a 5˜55 weight % alkali metal hydroxide aqueous solution, at a scanning speed (V) in the range between 2 μm/sec and 130 μm/sec which scanning speed satisfies simultaneously both the following conditions: V≦0.34P+13 and V≦-0.19P+190.
References Cited (Backward Citations)
JPS5129118A
Cited
JPS55117726A
Cited
US4379022A
Cited
JPS57212617A
Cited
US4439294A
Cited
JPS6060995A
Cited
JPS61260408A
Cited
JPS6227394A
Cited
JPS6283483A
Cited
US4751779A
Cited
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