US4991304A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Workpiece inspection method
Assignee: Renishaw PLC
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Filing: 1988-06-10
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Granted: 1991-02-12
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Expires: 2008-06-10
Abstract
Abstract A succession of nominally identical workpieces is measured using a probe on a coordinate measuring machine. To enable most of the workpieces to be probed at a fast speed (step 40), and compensate for the errors thereby introduced, one workpiece is also probed at a slow speed (step 32). For that workpiece, a series of error values is calculated (step 36) from the differences between the fast and slow measurements. The subsequent fast measurements on succeeding workpieces are corrected by making use of these error values (step 42).
Inventors
- 👤 David R. McMurtry
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 12:31
CPC Classifications
G; G01; G01B; G01B21/00; G01B21/02; G01B21/04; G01B21/045; G01B7/00; G01B7/004; G01B7/008
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
196 words
A method of inspecting a series of workpieces, in which a workpiece-sensing probe is moved into a position-sensing relationship with each workpiece and a position reading taken, the method comprising the following steps in any order in which (i) step (c) is performed after steps (a) and (b), and (ii) step (e) is performed after step (d): (a) moving the probe into the position-sensing relationship with one said workpiece at a relatively slow speed, and taking a position reading, (b) moving the probe into said position-sensing relationship with said one workpiece at a relatively fast speed, and taking a position reading, (c) recording a difference value representing the difference between the two readings of steps (a) and (b), (d) moving the probe into said position-sensing relationship with another said workpiece at the fast speed, and taking a position reading, and (e) using said recorded difference value to compensate the reading taken in step (d), thereby reducing any probe and dynamic errors in said reading; wherein steps (a), (b) and (c) are repeated at a plurality of points on said one workpiece, and steps (d) and (e) are performed at each corresponding point on said other workpiece.
Claim 2
Independent Claim
196 words
A method of inspecting a series of workpieces, in which a workpiece-sensing probe is moved into a position-sensing relationship with each workpiece and a position reading taken, the method comprising the following steps in any order in which (i) step (c) is performed after steps (a) and (b), and (ii) step (e) is performed after step (d): (a) moving the probe into the position-sensing relationship with one said workpiece at a relatively slow speed, and taking a position reading, (b) moving the probe into said position-sensing relationship with said one workpiece at a relatively fast speed, and taking a position reading, (c) recording a difference value representing the difference between the two readings of steps (a) and (b), (d) moving the probe into said position-sensing relationship with another said workpiece at the fast speed, and taking a position reading, and (e) using said recorded difference value to compensate the reading taken in step (d), thereby reducing any probe and dynamic errors in said reading; wherein steps (a), (b) and (c) are repeated at a plurality of points on said one workpiece, and steps (d) and (e) are performed at each corresponding point on said other workpiece.
Claim 3
Dependent Claim
20 words
A method according to claim 1, wherein steps (d) and (e) are repeated on a succession of substantially identical workpieces.
Claim 4
Dependent Claim
14 words
A method according to claim 1, in which the probe is a trigger probe.
Claim 5
Dependent Claim
32 words
A method according to claim 3, in which the probe is calibrated or datumed at the relatively slow speed, giving an offset which is used to correct the reading in step (a).
Claim 6
Dependent Claim
30 words
A method according to claim 1, in which the probe is a measurement probe, and each of steps (a), (b) and (d) is performed as part of a scanning process.
Claim 7
Independent Claim
188 words
A method of inspecting a series of identical workpieces, in which a workpiece sensing probe is moved into a position-sensing relationship with each workpiece and a position reading taken, the method comprising the following steps in any order in which (i) step (c) is performed after steps (a) and (b), and (ii) step (e) is performed after step (d): (a) moving the probe into a position-sensing relationship with at least one surface point of one workpiece at a relatively slow speed, and taking a position reading; (b) moving the probe into a position-sensing relationship with said surface point of said one workpiece at a relatively fast speed, and taking a position reading; (c) recording a difference value representing the difference between the two readings of steps (a) and (b); (d) moving the probe into said position-sensing relationship with another workpiece at a surface point corresponding to the surface point read on said one workpiece at said fast speed, and taking a position reading; and (e) using said recorded difference value to compensate the reading taken in step (d), thereby reducing any probe and dynamic errors in said reading.
Claim 8
Independent Claim
188 words
A method of inspecting a series of identical workpieces, in which a workpiece sensing probe is moved into a position-sensing relationship with each workpiece and a position reading taken, the method comprising the following steps in any order in which (i) step (c) is performed after steps (a) and (b), and (ii) step (e) is performed after step (d): (a) moving the probe into a position-sensing relationship with at least one surface point of one workpiece at a relatively slow speed, and taking a position reading; (b) moving the probe into a position-sensing relationship with said surface point of said one workpiece at a relatively fast speed, and taking a position reading; (c) recording a difference value representing the difference between the two readings of steps (a) and (b); (d) moving the probe into said position-sensing relationship with another workpiece at a surface point corresponding to the surface point read on said one workpiece at said fast speed, and taking a position reading; and (e) using said recorded difference value to compensate the reading taken in step (d), thereby reducing any probe and dynamic errors in said reading.
Claim 9
Dependent Claim
40 words
A method according to claim 6, wherein steps (a), (b) and (c) are repeated at a plurality of points on said one workpiece, and then subsequently steps (d) and (e) are performed at each corresponding point on said other workpiece.
Claim 10
Dependent Claim
20 words
A method according to claim 6, wherein steps (d) and (e) are repeated on a succession of substantially identical workpieces.
Claim 11
Dependent Claim
13 words
A method according to claim 6, wherein the probe is a trigger probe.
Claim 12
Dependent Claim
31 words
A method according to claim 9 wherein the probe is calibrated or datumed at the relatively slow speed, giving an offset which is used to correct the reading in step (a).
Claim 13
Dependent Claim
29 words
A method according to claim 6, wherein the probe is a measurement probe, and each of steps (a), (b) and (d) is performed as part of a scanning process.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-02-11 | 1994-08-13 | 1995-02-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-02-11 | 1998-08-13 | 1999-02-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-02-11 | 2002-08-13 | 2003-02-12 | $7700.00 | Window Closed / Lapsed |