Measurement method and apparatus

Patent metadata

Field	Value
Publication number	US-11163288-B2
Application number	US-201615562833-A
Country	US
Kind code	B2
Filing date	Mar 30, 2016
Priority date	Apr 9, 2015
Publication date	Nov 2, 2021
Grant date	Nov 2, 2021

Abstract

A method is described for analysing probe data collected by a scanning probe carried by a machine tool. The probe data is collected as the machine tool moves or scans the scanning probe along a scan path relative to a workpiece. The method includes a step of identifying a property of the scan path used by the machine tool from a characteristic of the collected probe data. In this manner, the scan path can be identified from the probe data alone without having to receive any position data from the machine tool.

First claim

The invention claimed is:

1. A method for analysing probe data collected by a scanning probe carried by a machine tool, the probe data being collected as the machine tool moves the scanning probe along a scan path relative to a workpiece, the method comprising:
a step of identifying a property of the scan path traversed by the scanning probe, from a characteristic of the collected probe data alone, without using any information from the machine tool including any positional data indicating relative positions of the scanning probe moving along the scan path as controlled by the machine tool.

2. The method according to claim 1 , wherein the step of identifying a property of the scan path traversed by the scanning probe comprises identifying a type of scan path from a plurality of different types of scan path.

3. The method according to claim 1 , wherein the step of identifying a property of the scan path traversed by the scanning probe comprises identifying a scan path from a plurality of different scan paths.

4. The method according to claim 1 , where the characteristic of the collected probe data comprises an inherent characteristic of the probe data that is associated with a measurement of a feature of the workpiece.

5. The method according to claim 4 , wherein the scanning probe comprises a contact scanning probe having a deflectable stylus and the inherent characteristic comprises a variation in a direction of stylus deflection and/or a magnitude of stylus deflection.

6. The method according to claim 1 , wherein the characteristic of the collected probe data comprises a variation in probe data provided by one or more variations introduced into the scan path to allow the scan path to be identified.

7. The method according to claim 6 , wherein the scan path traversed by the scanning probe comprises at least one signaling segment that produces probe data having an identifiable characteristic.

8. The method according to claim 1 , wherein the collected probe data comprises a discrete set of data points collected between the machine tool issuing instructions to the scanning probe to start collecting probe data and to stop collecting probe data.

9. The method according to claim 8 , wherein the characteristic of the collected probe data comprises a number of data points within the discrete set of data points.

10. The method according to claim 1 , wherein probe data is collected as the machine tool moves the scanning probe along a plurality of scan paths relative to the workpiece, wherein a property of each of the plurality of scan paths is identified from a characteristic of the probe data collected from each scan path without using any information from the machine tool including any positional data indicating relative positions of the scanning probe moving each scan path as controlled by the machine tool.

11. The method according to claim 1 , comprising a further step of analysing the probe data to extract measurement information, wherein a type of analysis performed on the probe data is determined from the identified property of the scan path.

12. The method according to claim 1 , wherein the step of identifying a property of the scan path traversed by the scanning probe is performed on a processor that is external to the machine tool.

13. The method according to claim 1 , wherein the scanning probe comprises a contact scanning probe having a deflectable stylus and at least one transducer for measuring an amount of deflection of the stylus.

14. A non-transitory computer readable medium storing a program comprising instructions which, when executed on a suitable computer, implement the method according to claim 1 .

15. The method according to claim 1 , wherein:
when the scanning probe traverses a circular scan path, the identified property of the scan path indicates whether the circular scan path is a circular scan of a boss or a bore of the workpiece, and
when the scanning probe traverses a linear scan path, the identified property of the scan path indicates a length of the linear scan path.

16. An apparatus for analysing probe data collected by a scanning probe carried by a machine tool, the probe data being collected as the machine tool moves the scanning probe along a scan path relative to a workpiece, the apparatus comprising:
a processor that identifies a property of the scan path traversed by the scanning probe, from a characteristic of the collected probe data alone, without using any information from the machine tool including any positional data indicating relative positions of the scanning probe moving along the scan path as controlled by the machine tool.

17. A method for analysing probe data collected by a scanning probe carried by a machine tool, the probe data being collected as the machine tool moves the scanning probe along a scan path relative to a workpiece, the method comprising:
a step of using the collected probe data alone to identify a property of the scan path traversed by the scanning probe, without using any information from the machine tool including any positional data indicating relative positions of the scanning probe moving along the scan path as controlled by the machine tool.

18. A machine tool setup method for determining one or more work offset corrections for a workpiece mounted within a machine tool, the method comprising steps of:
a) using the machine tool to drive a scanning probe along a predefined scan path relative to a workpiece, the workpiece having been placed in a nominal position within the machine tool;
b) collecting probe data from the scanning probe that is indicative of a position of surface of the workpiece relative to the scanning probe whilst the scanning probe is being driven along the scan path; and
c) comparing the acquired probe data to probe data that would be expected if an object was placed in a nominal location and orientation to generate one or more work offset corrections for feeding to the machine tool,
wherein step (c) comprises a step of identifying a property of the scan path traversed by the scanning probe, from a characteristic of the acquired probe data alone without using any information from the machine tool including any positional data indicating relative positions of the scanning probe moving along the scan path as controlled by the machine tool.

Assignees

• Renishaw Plc

Inventors

• Marshall Derek
• Ould John Charles

Classifications

• G01B21/047 Primary

  Accessories, e.g. for positioning, for tool-setting, for measuring probes · CPC title

• G05B19/4083

  Adapting program, configuration · CPC title

• G05B19/401 Primary

  characterised by control arrangements for measuring, e.g. calibration and initialisation, measuring workpiece for machining purposes (G05B19/19 takes precedence) · CPC title

• B23Q17/00 Primary

  Arrangements for {observing,} indicating or measuring on machine tools (for automatic control or regulation of feed movement, cutting velocity or position of tool or work B23Q15/00) · CPC title

• G01B21/042

  Calibration or calibration artifacts (G01B3/30, G01B9/02072 take precedence) · CPC title