Method of determining a radius of a cutting end of a tool for a turning machine

• US 9,618,927 B2
• Filed: 04/15/2014
• Issued: 04/11/2017
• Est. Priority Date: 04/15/2014
• Status: Expired due to Fees

• Current Assignee: Pratt & Whitney Canada Corporation (Rtx Corporation)
• Original Assignee: Pratt & Whitney Canada Corporation (Rtx Corporation)
• Inventors: Gagnon, Lafleche, Guiassa, Rachid, St-Jacques, Philippe
• Primary Examiner(s): Wu, Qing
• Application Number:
  US14/252,910
• Publication Number:
  US 20150292854A1
• Time in Patent Office: 1,092 Days
• Field of Search: None
• CPC Class Codes: G01B 5/08 for measuring diameters G01B5/0035 takes precedence; measuring radius of curvature G01B5/213
• CPC Class Codes: G01B 5/213 for measuring radius of curvature
• CPC Class Codes: G05B 19/19 characterised by positioning or contouring control systems, e.g. to control position from one programmed point to another or to control movement along a programmed continuous path
• CPC Class Codes: G05B 19/401 characterised by control arrangements for measuring, e.g. calibration and initialisation, measuring workpiece for machining purposes G05B19/19 takes precedence
• CPC Class Codes: G05B 2219/37404 Orientation of workpiece or tool, surface sensor
• CPC Class Codes: G05B 2219/37405 Contact detection between workpiece and tool, probe, feeler
• CPC Class Codes: G05B 2219/37406 Detect position of detector contact point relative to reference on tool slide
• CPC Class Codes: G05B 2219/37407 Detect position of detector contact point relative to reference on tool

Abstract

A method of determining a radius of a cutting end of a tool for a turning machine using a touch probe is provided. One of the cutting end and the touch probe is movable relative to a reference frame having a first axis and a second axis and having a reference point trackable in the reference frame. The method comprises establishing a first contact point and recording a first coordinate of the reference point on the first axis; establishing a second contact point and recording a second coordinate of the reference point on the second axis; establishing a third contact point and recording a third coordinate of the reference point on the first axis and a fourth coordinate of the reference point on the second axis upon contact; and determining a radius of the cutting end based on the first, second, third and fourth coordinates.

Claims

1. A method of determining with at least one electronic control unit a radius of a cutting end of a tool for a turning machine using a touch probe, one of the cutting end and the touch probe being movable as controlled by the at least one electronic control unit relative to a reference frame having a first axis and a second axis and having a reference point trackable in the reference frame of the at least one electronic control unit, the method comprising:

a) establishing, using the at least one electronic control unit, a first contact point between the touch probe and the cutting end and recording, using the at least one electronic control unit, a first coordinate of the reference point on the first axis, the first contact point having a known coordinate on the first axis; and

b) establishing, using the at least one electronic control unit, a second contact point between the touch probe and the cutting end and recording, using the at least one electronic control unit, a second coordinate of the reference point on the second axis, the second contact point having a known coordinate on the second axis; and

c) establishing, using the at least one electronic control unit, a third contact point between the touch probe and the cutting end by moving an end point of the one of the cutting end and the touch probe along a predetermined direction at an angle with the first and second axes as controlled by the at least one electronic control unit and recording, using the at least one electronic control unit, a third coordinate of the reference point on the first axis and a fourth coordinate of the reference point on the second axis upon contact, the pre-determined direction being dependent on the coordinate of the first contact point on the first axis and the coordinate of the second contact point on the second axis, the end point being offset from the reference point by an amount deduced from the first coordinate and the second coordinate recorded at steps a) and b); and

d) determining, using the at least one electronic control unit, a radius of the cutting end based on the first, second, third and fourth coordinates.

2. The method as defined in claim 1, wherein steps a), b) and c) are performed within the turning machine.

3. The method as defined in claim 1, wherein steps a) and b) are performed in any order.

4. The method as defined in claim 1, wherein at least one of steps a), b) and c) is performed using a different touch probe.

5. The method as defined in claim 1, wherein the probe is fixed relative to the reference frame and the cutting end is movable relative to the reference frame.

6. The method as defined in claim 1, wherein determining the radius R of the tool comprises determining a radius R smaller than 0.1 inch.

7. The method as defined in claim 1, wherein determining the radius R of the tool comprises determining a radius R between 0.01 and 0.1 inch.

8. The method as defined in claim 1, wherein the predetermined direction is at 45degrees from the first and second axes.

9. The method as defined in claim 1, wherein the first axis is an X-axis and the second axis is a Z-axis;

the predetermined direction is at an angle a from the X-axis and the Z-axis;

the reference point is P₀;

the known position of the first point of the one of the cutting edge and the touch probe on the X-axis is X₂₄;

step a) is performed at time t =t1;

the first coordinate is P₀^t=t1(X);

the known position of the second point of the one of the cutting edge and the touch probe on the Z-axis is Z₂₆;

step b) is performed at time t=t2;

the second coordinate is P₀^t=t2(Z);

the known position of the third point of the one of the cutting edge and the touch probe on the X-axis is Z₃₂;

step c) is performed at time t=t3;

the third coordinate is P₀^t=t3(X);

the known position of the third point of the one of the cutting edge and the touch probe on the Z-axis is Z₃₂;

the fourth coordinate is P₀^t=t3(Z); and

the radius R is

10. The method as defined in claim 1, wherein establishing the first contact point comprises contacting the touch probe on a first flat side, the first flat side being parallel to the second axis;

establishing the second contact point comprises contacting the touch probe on a second flat side, the second flat side being parallel to the first axis; and

establishing the third contact point comprises contacting the touch probe on one of a rounded corner and an angled corner joining the first flat side and the second flat side.

11. A method of determining with at least one electronic control unit a radius of a cutting end of a tool for a turning machine using a touch probe, one of the cutting end and the touch probe being movable as controlled by the at least one electronic control unit relative to a reference frame having a first axis and a second axis and having a reference point trackable in the reference frame of the at least one electronic control unit, the method comprising:

a) recording, using the at least one electronic control unit, a first coordinate of the reference point on the first axis upon contacting the touch probe and the cutting end at a first contact point having a known coordinate on the first axis;

b) calculating, using the at least one electronic control unit, a first offset of an end point of the one of the cutting end and the touch probe relative to the reference point on the first axis based on the first coordinate;

c) recording, using the at least one electronic control unit, a second coordinate of the reference point on the second axis upon contacting the touch probe and the cutting end at a second contact point having a known coordinate on the second axis; and

d) calculating, using the at least one electronic control unit, a second offset of the end point relative to the reference point on the second axis based on the second coordinate;

e) recording, using the at least one electronic control unit, a third coordinate of the reference point on the first axis and a fourth coordinate of the reference point on the second axis upon moving an end point of the one of the cutting end and the touch probe along a predetermined direction as controlled by the at least one electronic control unit and contacting the touch probe and the cutting end at a third contact point along the predetermined direction, the third contact point having known coordinates on the first and second axes, the predetermined direction being at an angle with the first and second axes and being determined from the coordinate of the first contact point on the first axis and the coordinate of the second contact point on the second axis, the end point calculated using the first and second offsets; and

f) determining, using the at least one electronic control unit, a radius of the cutting end based on the first, second, third and fourth coordinates.

12. The method as defined in claim 11, wherein step b) is performed at any time between steps a) and e).

13. A turning machine comprising:

a tool having a cutting end;

a touch probe having two flat faces and one of a rounded and angled corner joining the two flat faces; and

an electronic control unit (ECU) controlling at least one of the tool and the probe to move in a reference frame to establish separate contacts between the probe and the tool at a first point on one of the two flat faces, at a second point on the other one of the two flat faces and at a third point on the one of the rounded and angled corner, the ECU being configured to record coordinates of a reference point of the tool or the probe during the separate contacts so as to calculate a radius of the cutting end.

14. The turning machine as defined in claim 13, wherein the touch probe is fixed and the ECU controls the tool to move in the reference frame.