US5030920A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of detecting wear of cutting tool by ascertaining a tool workpiece contact resistance
Assignee: Sumitomo Electric Industries Ltd
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Filing: 1989-10-13
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Granted: 1991-07-09
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Expires: 2009-10-13
Abstract
Abstract A method for detecting wear of a cutting tool for cutting a workpiece measures the contact resistance between the cutting tool and the workpiece for detecting wear of the cutting tool from a change in the contact resistance, whereby such wear of the cutting tool can be reliably and accurately measured.
Inventors
- 👤 Takashi Nakamura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 03:11
CPC Classifications
B; B23; B23Q; B23Q15/00; B23Q15/007; B23Q15/16; G; G05; G05B; G05B19/00; G05B19/02; G05B19/18; G05B19/406; G05B19/4065; B23Q17/00; B23Q17/09; G05B2219/00; G05B2219/30; G05B2219/37; G05B2219/37256
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
163 words
A method of detecting wear of a cutting tool for cutting a workpiece, comprising the following steps: (a) coating said cutting tool with a coating layer having a high tool workpiece contact resistance compared to an uncoated tool for an improved detection of wear; (b) feeding an electric current through said coated cutting tool and said workpiece; (c) measuring a potential (Em) developed across said cutting tool and said workpiece while said electric current is flowing; (d) measuring said electric current during a cutting operation; (e) interrupting said electric current flowing between said cutting tool and said workpiece; (f) measuring, while said electric current is interrupted, a thermoelectromotive force (Et) generated by contact between said cutting tool and said workpiece; (g) subtracting said thermoelectromotive force (Et) from said potential (Em) and dividing the potential difference by said current value for ascertaining said contact resistance between said cutting tool and said workpiece; and (h) determining wear of said cutting tool from said contact resistance.
Claim 2
Independent Claim
163 words
A method of detecting wear of a cutting tool for cutting a workpiece, comprising the following steps: (a) coating said cutting tool with a coating layer having a high tool workpiece contact resistance compared to an uncoated tool for an improved detection of wear; (b) feeding an electric current through said coated cutting tool and said workpiece; (c) measuring a potential (Em) developed across said cutting tool and said workpiece while said electric current is flowing; (d) measuring said electric current during a cutting operation; (e) interrupting said electric current flowing between said cutting tool and said workpiece; (f) measuring, while said electric current is interrupted, a thermoelectromotive force (Et) generated by contact between said cutting tool and said workpiece; (g) subtracting said thermoelectromotive force (Et) from said potential (Em) and dividing the potential difference by said current value for ascertaining said contact resistance between said cutting tool and said workpiece; and (h) determining wear of said cutting tool from said contact resistance.
Claim 3
Dependent Claim
38 words
The method in accordance with claim 1, wherein said coating step is performed by first applying a coating of titanium carbide to said cutting tool and then applying a coating of aluminum oxide on said titanium carbide coating.
Claim 4
Dependent Claim
16 words
The method in accordance with claim 1, wherein said cutting tool is made of cemented carbide.
Claim 5
Dependent Claim
21 words
The method in accordance with claim 1, wherein said ascertaining of said contact resistance is performed by a four terminal method.
Claim 6
Dependent Claim
20 words
The method of claim 1, wherein said coating step is performed by applying an aluminum oxide coating to said tool.
Claim 7
Dependent Claim
20 words
The method of claim 1, wherein said coating step is performed by applying a titanium carbide coating to said tool.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1994-07-08 | 1995-01-07 | 1995-07-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-07-08 | 1999-01-07 | 1999-07-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-07-08 | 2003-01-07 | 2003-07-09 | $7700.00 | Window Closed / Lapsed |