Apparatus and method for detecting damage to tool in machine

• US 9,760,083 B2
• Filed: 11/01/2011
• Issued: 09/12/2017
• Est. Priority Date: 12/09/2010
• Status: Active Grant

• Current Assignee: DN Solutions Company Limited (DN AUTOMOTIVE Corp.)
• Original Assignee: Doosan Machine Tools Co., Ltd
• Inventors: Chung, Dae Hyuk, Sung, Dae Jung
• Primary Examiner(s): Everett, Christopher E
• Assistant Examiner(s): Huntley, Michael J
• Application Number:
  US13/992,417
• Publication Number:
  US 20130253670A1
• Time in Patent Office: 2,142 Days
• Field of Search: 700 79, 700175
• CPC Class Codes: B23Q 17/0961 by measuring power, current or torque of a motor
• CPC Class Codes: G05B 19/4065 Monitoring tool breakage, life or condition

Abstract

The apparatus for detecting damage to the tool in the machine and the method of detecting damage to the tool according to the present disclosure are applied to a machine, such as a CNC, to detect and control damage to a tool and possibility of damage in advance, thereby efficiently managing processing work by the machine while achieving safety of the machine.

Claims

1. An apparatus for detecting damage to a tool in a machine capable of continuously performing processing work by maintaining numerical accuracy and preventing damage to the tool, comprising:

a detector configured to receive a signal according to torque from a servo and a spindle of a machine;

a simulator configured to calculate a prior processing condition by using information inputted from a numerical controller of the machine,

wherein the information inputted from the numerical controller includes a three-dimensional prediction based on the torque obtained from the signal received by the detector, prior corresponding coordinates based on an interpolation, and a predicted range of torque based on past corresponding torque information,

wherein the prior processing condition includes at least one of a depth of cut, a feed, and a material of a workpiece;

a critical torque calculator configured to calculate the predicted range of torque by using an interpolation of the prior processing condition calculated by the simulator, wherein an addition of the prior processing condition is performed in a direction of widening an area in which the interpolation is available;

a critical torque data storing unit configured to store an upper limit value and a lower limit value of the predicted range of torque calculated by the critical torque calculator;

a comparator configured to compare the torque indicated by the signal received by the detector and the predicted range of torque calculated by the critical torque calculator; and

a machine processing operation controller configured to control a processing operation of the machine according to a result of the comparison by the comparator,

wherein the machine processing operation controller comprises;

a tool damage prevention unit configured to adjust rotation speed or a feed of a workpiece of the machine so as to limit abrasion of the workpiece, according to the result of the comparison by the comparator; and

a tool damage prediction unit configured to communicate a warning signal to an operator of the machine through an alarm means according to the result of the comparison by the comparator.

2. The apparatus of claim 1, wherein the machine processing operation controller further comprises:

a tool damage detection unit configured to stop the processing operation of the machine by controlling the numerical controller according to the result of the comparison by the comparator.

3. The apparatus of claim 1, further comprising a tool database configured to set port information of a tool magazine and a material of the workpiece as a pair of elements of reference information, and torque information detected by the detector.

4. The apparatus of claim 1, wherein the area in which the interpolation is available includes a convex area associated with known processing conditions, the convex area having a convex shape having a minimum size and including the prior processing condition, and the convex area being formed by positioning the prior processing condition at a corner or a boundary surface of the convex area.

5. The apparatus of claim 4, wherein the critical torque calculator is configured such that:

when a new processing condition is positioned outside of the convex area, the critical torque calculator expands the convex area by the interpolation of the predicted range of torque.

6. The apparatus of claim 5, wherein the critical torque calculator is configured such that when an existing processing condition is included in a newly expanded convex area, the critical torque calculator deletes the existing processing condition.

7. A method of detecting damage to a tool in a machine capable of continuously performing processing work by maintaining numerical accuracy and preventing damage to the tool, comprising the steps of:

(A) receiving a signal according to torque from a servo and a spindle of a machine;

(B) calculating a prior processing condition by using information inputted from a numerical controller of the machine,

wherein the information inputted from the numerical controller includes a three-dimensional prediction based on the torque obtained from the received signal, prior corresponding coordinates based on an interpolation, and a predicted range of torque based on past corresponding torque information, and

wherein the prior processing condition includes at least one of a depth of cut, a feed, and a material of a workpiece;

(C) adding a new tool to be used in processing and setting tool information;

(D) calculating a range and a threshold value of torque predicted to be generated during processing work by using the information stored in step (C) and the prior corresponding coordinates based on the interpolation from step (B), and storing the range and the threshold value of the torque, wherein an addition of the prior processing condition is performed in a direction of widening an area in which the interpolation is available;

(E) comparing the torque indicated in the signal received in step (A) with the range and the threshold value calculated in step (D); and

(F) controlling a processing operation of the machine according to a result of the comparison in step (E),

wherein in step (F), a mode for controlling the processing operation includes a tool damage detection mode, a tool damage prevention mode, and a tool damage prediction mode, and

in the tool damage prevention mode, when it is determined that the torque indicated in the signal received in step (A) approaches the threshold value calculated in step (D) within a first reference value, an operation of the machine is controlled so that a processing condition of the processing operation is changed so as to limit damage to the tool;

in the tool damage prediction mode, when it is determined that the torque indicated in the signal received in step (A) approaches the threshold value calculated in step (D) within a second reference value smaller than the first reference value, communicating a warning signal to an operator of the machine through an alarm means according to the comparison in step (E); and

in the tool damage detection mode, when the torque indicated in the signal received in step (A) exceeds the threshold value calculated in step (D), the process operation of the machine is stopped so as to limit damage to the machine.

8. The method of claim 7, wherein the area in which the interpolation is available includes a convex area associated with known processing conditions, the convex area having a convex shape having a minimum size and including the prior processing condition, and the convex area being formed by positioning the prior processing condition at a corner or a boundary surface of the convex area.

9. The method of claim 8, wherein when a new processing condition is positioned outside of the convex area, the convex area is expanded by the interpolation of the predicted range of torque.

10. The method of claim 9, further comprising wherein when an existing processing condition is included in a newly expanded convex area, the existing processing condition is deleted.