Apparatus for directly measuring machine tool wear

• US 4,176,396 A
• Filed: 09/23/1977
• Issued: 11/27/1979
• Est. Priority Date: 09/23/1977
• Status: Expired due to Term

• Current Assignee: Charles Stark Draper Laboratory Incorporated
• Original Assignee: Charles Stark Draper Laboratory Incorporated
• Inventors: Howatt, John R.
• Primary Examiner(s): Wise, Edward J.
• Application Number:
  US05/836,220
• Time in Patent Office: 795 Days
• Field of Search: 364/474, 364/551, 364/111, 73/618, 73/104, 73/619
• US Class Current: 702/34
• CPC Class Codes: G01N 2203/021 Treatment of the signal; Calibration
• CPC Class Codes: G01N 3/58 Investigating machinability by cutting tools; Investigating the cutting ability of tools

Abstract

A system for determining cutting-tool wear which utilizes a sensor for producing an output signal representing the cutting profile of the tool and a data processing system using microprocessor control which is responsive to the sensor for storing information concerning such cutting profile when the tool is initially installed and for comparing updated cutting profile information with the stored initial cutting profile information to provide output information concerning the wear characteristics of the tool. The wear information can be displayed, either visually or audibly, or can be supplied to an external data processor, such as the overall machine tool processor, for use therein. The system includes means for correcting errors which arise because of sensor and tool bit characteristics.

Claims

1. A system for determining the wear characteristics of at least one cutting tool comprising

at least one sensing means for producing an output signal representing the cutting profile characteristics of said at least one cutting tool as said tool passes adjacent thereto;

data processing means responsive to said at least one sensing means output signal for storing information concerning said cutting profile characteristics when said cutting tool is initially installed for use and for obtaining up-dated information concerning said cutting profile characteristics during subsequent use of said cutting tool;

means for comparing said initial stored profile characteristics information with said up-dated profile characteristics information to provide output information concerning the wear characteristics of said at least one cutting tool.

2. A system in accordance with claim 1 and further including display means responsive to said output information for providing said information in a sense-responsive form for an operator of said system.

3. A system in accordance with claim 2 wherein said display means comprises a visual display means.

4. A system in accordance with claim 2 wherein said display means comprises an audible display means.

5. A system in accordance with claim 4 wherein said audible display means produces an audible alarm signal when said output information indicates that the wear characteristics of said at least one cutting tool exceeds preselected limits.

6. A system in accordance with claim 1 wherein said sensing means provides an analog output signal and said data processing means is a digital processing means and includes means for converting said analog output signal to a digital output signal for processing by said digital processing means.

7. A system in accordance with claim 6 wherein said digital data processing means includes

a memory unit capable of storing said initial profile characteristics information and said updated profile characteristics information,

a microprocessor unit for controlling the storage of said initial and said updated profile characteristics information in said memory unit and the access to said stored information, for controlling the comparison of said initial and said updated profile characteristics information and for controlling the supplying of said output information concerning said wear characteristics.

8. A system in accordance with claim 7 wherein said memory unit comprises a random-access-memory for storing said profile characteristics information initially obtained and subsequently offered during use and a read-only-memory for storing program information for use by said microprocessor unit.

9. A system in accordance with claim 1 and further including means for interrupting the operation of said data processing means when information concerning a cutting tool profile is produced from said sensing means and for permitting said data processing means to resume its operation when said cutting tool profile information has been stored.

10. A system in accordance with claim 1 and further including interface means for providing an interconnection of said system with one or more systems external thereto.

11. A system in accordance with claim 10 wherein said interface means includes means for interrupting the operation of said data processing means in response to an external data processor means to provide for communication between said data processing means and said external data processor means.

12. A system in accordance with claim 1 and further including means for correcting errors which arise because of sensor and tool bit characteristics.

13. A system in accordance with claim 12 wherein said error correcting means includes

means for storing error information in accordance with a predetermined error equation associated with a selected cutting tool type;

and

means for comparing said error information with said updated cutting tool profile information to produce corrected cutting tool profile information.

14. A system in accordance with claim 12 wherein said error correcting means includes

means for comparing the initial cutting tool profiles of each of said at least one cutting tool with a predetermined ideal cutting tool profile;

and

means for storing information representing differences therebetween, said difference information being available for use in correcting said updated cutting tool profile information.

15. A system in accordance with claim 12 wherein said error correcting means includes

means for storing predetermined error information concerning said at least one cutting tool profile, said predetermined error information being available for use in correcting said updated cutting tool profile information received from said sensing means.