MACHINING PROCESS AND APPARATUS FOR MACHINING

• US 20140059856A1
• Filed: 08/22/2013
• Published: 03/06/2014
• Est. Priority Date: 09/03/2012
• Status: Active Grant

• Current Assignee: Rolls-Royce PLC (Rolls-Royce Holdings Plc)
• Original Assignee: Rolls-Royce PLC (Rolls-Royce Holdings Plc)
• Inventors: SIMMONS, Christopher Alan, HANCOCK, Mark David
• Granted Patent: US 9,291,058 B2
• Time in Patent Office: Days
• US Class Current: 29/889.7
• CPC Class Codes: B23P 15/04 turbine or like blades from several pieces
• CPC Class Codes: F01D 5/14 Form or construction selecting particular materials, measures against erosion or corrosion F01D5/28
• 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 19/404 characterised by control arrangements for compensation, e.g. for backlash, overshoot, tool offset, tool wear, temperature, machine construction errors, load, inertia G05B19/19, G05B19/41 take precedence
• CPC Class Codes: G05B 2219/37205 Compare measured, vision data with computer model, cad data
• CPC Class Codes: G05B 2219/45147 Machining blade, airfoil
• CPC Class Codes: G05B 2219/49025 By positioning plurality of rods, pins to form together a mold, maquette
• CPC Class Codes: Y10T 29/49336 Blade making

Abstract

A method of determining a tool path to machine a component, the method comprising the steps of: securing the component to a fixture having a zero point alignment datum, the component and the fixture having respective mobile reference points; aligning the fixture mobile reference points to target reference points on the machine tool; aligning a digitised model of the component to the component mobile reference points; determining the position of the component on the fixture from the component mobile reference points and the fixture mobile reference points; and adjusting a nominal tool path for the machine tool dependent on the position of the component.

Claims

1. A method of determining a tool path to machine a component, the method comprising the steps of:

securing the component to a fixture having a zero point alignment datum, the component and the fixture having respective mobile reference points;

aligning the fixture mobile reference points to target reference points on a machine tool;

aligning a digitised model of the component to the component mobile reference points;

determining the position of the component on the fixture from the component mobile reference points and the fixture mobile reference points; and

adjusting a nominal tool path for the machine tool dependent on the position of the component.

2. A method according to claim 1, further comprising the steps of locating the fixture on the machine tool using the zero point alignment datum and machining the component using the adjusted tool path.

3. A method according to claim 2, wherein the nominal tool path is adjusted before the fixture is located on the machine tool.

4. A method according to claim 1, wherein the mobile reference points may be detected without contact of a detector.

5. A method according to claim 4, wherein the mobile reference points emit or reflect radiation.

6. A method according to any one of claims 1, wherein the location of one or more of the mobile reference points is determined by a touch probe.

7. A method according to claim 1, wherein the component is an aerofoil having a foot, a tip, a first flank and an opposing second flank, wherein the fixture has a foot clamp for clamping the foot of an aerofoil and a tip clamp for clamping the tip of the aerofoil, and further having an array of supports between the foot clamp and the tip clamp, each support within the array being independently addressable to one of the aerofoil flanks when the aerofoil is secured to the fixture.

8. A method according to claim 7, wherein the tip of the aerofoil has a surplus of material with the tip clamp clamping the surplus material.

9. A method according to claim 7, wherein each support is functionally connected to pneumatic or hydraulic actuator.

10. A method according to claim 9, wherein each support has a locking device which locks the support against the aerofoil flank.

11. A method according to claim 7, wherein the fixture comprises at least three alignment pillars that is located beyond the array of supports and which may be detected by non contact means to provide mobile reference points.