Method of determining tool breakage

• US 6,161,055 A
• Filed: 12/01/1995
• Issued: 12/12/2000
• Est. Priority Date: 05/17/1993
• Status: Expired due to Term

• Current Assignee: LMI Technologies Inc.
• Original Assignee: Laser Measurement International Inc.
• Inventors: Pryor, Timothy R.
• Primary Examiner(s): Grant, William
• Assistant Examiner(s): Garland, Steven R.
• Application Number:
  US08/566,449
• Time in Patent Office: 1,838 Days
• Field of Search: 364/474.16, 364/474.17, 382/152, 382/204, 408/6, 408/16, 408/8, 702/34, 700/174, 700/175, 700/177
• US Class Current: 700/175
• CPC Class Codes: B23Q 17/0957 Detection of tool breakage detecting failure of drills B23B49/001
• CPC Class Codes: G05B 19/4065 Monitoring tool breakage, life or condition
• CPC Class Codes: G05B 2219/37227 Probing tool for its geometry
• CPC Class Codes: G05B 2219/37233 Breakage, wear of rotating tool with multident saw, mill, drill
• CPC Class Codes: G05B 2219/37234 Monitor tool before, after and during machining
• CPC Class Codes: G05B 2219/37246 Compare estimated torques of different axis with reference for breakage
• CPC Class Codes: G05B 2219/37575 Pre-process, measure workpiece before machining

Abstract

A method of determining the breakage of a tool in a machine tool is disclosed. The method automatically senses a physical characteristic of the operation of the machine during a cutting operation. Then, if the sensed value indicates a potential break in the cutting edge of the tool, an electro-optical sensor used to examine the shape of the tool and to automatically determine whether the tool shape is also indicative of tool breakage.

Claims

1. A method for determining tool breakage in a machine tool comprising the steps of:

providing an electro-optical sensor in said machine tool capable of automatically determining a shape of the cutting edge of said tool,

automatically sensing a physical characteristic of an operation of said machine tool during cutting with said cutting edge,

automatically determining that the sensed value of the operation of the machine tool has provided information indicative of a potential break of the cutting edge of said tool,

automatically examining the shape of said tool with said electro-optical sensor when information indicative of a potential break has been sensed, and

automatically determining if said shape is also indicative of tool breakage.

2. A method according to claim 1, further comprising the steps of:

illuminating the edge of said tool,

imaging said tool edge onto a two dimensional image scanning device,

scanning said tool edge image by computer from the data obtained from the positions on said device,

determining the two dimensional contour of the tool edge with the computer.

3. A method according to claim 2 wherein a display of said contour of the tool edge is made.

4. A method according to claim 2 wherein a display is further able to display a previous or expected tool contour.

5. A method according to claim 1 and further including the step of:

interrupting of said cut when information indicative of a potential break has been determined immediately to perform the automatic electro-optical examination of said tool shape.

6. A method according to claim 1 wherein the physical characteristic sensed is force.

7. A method according to claim 1 wherein a two dimensional shape of the cutting edge is determined and examined with the electro-optical sensor.

8. A method according to claim 1 wherein said examining step examines a shape of an edge of the tool.

9. A method according to claim 8 wherein said determining step determines if an edge of the tool is broken.