Adaptive machining of components

• US 9,817,393 B2
• Filed: 03/05/2014
• Issued: 11/14/2017
• Est. Priority Date: 03/08/2013
• Status: Active Grant

• Current Assignee: Rolls-Royce Corporation (Rolls-Royce Holdings Plc)
• Original Assignee: Rolls-Royce Corporation (Rolls-Royce Holdings Plc)
• Inventors: Junod, Larry Allen, Rhodes, Jeffrey F.
• Primary Examiner(s): Coyer, Ryan
• Application Number:
  US14/198,103
• Publication Number:
  US 20140257551A1
• Time in Patent Office: 1,350 Days
• Field of Search: 700 97
• CPC Class Codes: G05B 19/4097 characterised by using design data to control NC machines, e.g. CAD/CAM G05B19/4093 takes precedence
• CPC Class Codes: G05B 19/4207 in which a model is traced or scanned and corresponding data recorded
• CPC Class Codes: G05B 2219/35128 Propeller blade
• CPC Class Codes: G05B 2219/45147 Machining blade, airfoil

Abstract

In some examples, an adaptive machining system may include a model comparison unit, a compromise shape determination unit, and a program modification unit. The model comparison unit can be configured to compare electronic measured dimensional surface data of a component with an electronic surface model of the component. The compromise shape determination unit can be configured to determine a compromise shape for the component based on the comparison. The program modification unit can be configured to modify a machine tool program code based on the compromise shape.

Claims

1. An adaptive machining system comprising:

a numerical control (NC) machine configured to machine a component based on a machine tool program code;

a model comparison unit configured to compare electronic measured dimensional surface data of the component with an electronic surface model of the component;

a compromise shape determination unit configured to determine a compromise shape for the component based on the comparison, wherein the compromise shape determination unit comprises a model transformation determination unit configured to modify the electronic surface model based on the comparison, wherein the compromise shape determination unit comprises an offset distribution determination unit that is configured to determine a compromise offset distribution between the modified electronic surface model and the electronic measured dimensional surface data, wherein the offset distribution determination unit is configured to apply the compromise offset distribution to the modified electronic surface model to have a rate of contour deviation within a predetermined tolerance of 0.005 inch/inch; and

a program modification unit configured to modify the machine tool program code based on the compromise shape by modifying at least one line of the machine tool program code.

2. The adaptive machining system of claim 1, wherein the compromise shape determination unit is configured to determine the shape for the component based on component functionality and subsequent manufacturing steps.

3. The adaptive machining system of claim 1, wherein the electronic surface model comprises a surface model defined by CAD (Computer-Aided Design) spline knots.

4. The adaptive machining system of claim 1, wherein the model transformation determination unit is configured to modify the electronic surface model using a weighted nonlinear least squares minimization problem.

5. The adaptive machining system of claim 1, wherein the electronic surface model comprises a design intent surface of the component, and wherein the model transformation determination unit is configured to rotate and translate the design intent surface to best-fit the electronic measured dimensional surface data of the component.

6. The adaptive machining system of claim 1, wherein the compromise shape determination unit is configured to adjust the degree of compromise offset distribution based on a number of CAD (Computer-Aided Design) spline knots that define the compromise offset distribution.

7. The adaptive machining system of claim 1, wherein the offset distribution determination unit is configured to specify a tolerance on the magnitude and slope of the compromise offset distribution.

8. The adaptive machining system of claim 1, wherein the program modification unit is configured to modify the machine tool program code based on the compromise offset distribution.

9. The adaptive machining system of claim 1, wherein the program modification unit is configured to modify the machine tool program code based on the modified electronic surface model and the compromise offset distribution.

10. A method for machining a component comprising:

measuring geometric surface data of the component to produce electronic measured geometric surface data;

comparing the electronic measured geometric surface data with an electronic geometric model of the surface of the component;

changing the electronic geometric model based on the comparison to generate a changed electronic geometric model;

determining a compromise offset distribution between the changed electronic geometric model and the electronic measured geometric surface data;

applying the compromise offset distribution to the changed electronic geometric model to have a rate of contour deviation within a predetermined tolerance of 0.005 inch/inch;

editing program instructions for a machine tool path by modifying at least one line of the program instructions based on the comparison to produce edited program instructions; and

machining the component based on the edited program instructions.

11. The method of claim 10, wherein the electronic geometric model is defined by CAD (Computer-Aided Design) spline knots, and wherein comparing the electronic measured geometric surface data with the electronic geometric model of the surface of the component comprises comparing a set of the electronic measured geometric surface data to a location of the electronic geometric model of the surface of the component that is interpolated from the CAD spline knots.

12. The method of claim 10, further comprising:

morphing the changed electronic geometric model between the changed electronic geometric model and the electronic measured geometric surface data, wherein editing program instructions for a machine tool path based on the comparison to produce edited program instructions comprises editing the program instructions for the machine tool path based on the morphed model.

13. The method of claim 12, wherein changing the electronic geometric model based on the comparison comprises rotating and translating the electronic geometric model to best-fit the electronic measured geometric surface data.

14. A method for manufacturing an airfoil comprising:

measuring coordinate surface data of an airfoil spar surface to produce electronic measured coordinate surface data;

mathematically comparing the electronic measured coordinate surface data with an electronic curve function model of the airfoil spar surface;

changing the electronic curve function model based on the comparison to generate a changed electronic curve function model;

determining a compromise offset distribution between the changed electronic curve function model and the electronic measured coordinate surface data;

applying the compromise offset distribution to the changed electronic curve function model to have a rate of contour deviation within a predetermined tolerance of 0.005 inch/inch;

modifying numerical control machine instructions by modifying at least one line of the numerical control machine instructions for machining the airfoil spar surface based on the comparison to produce modified numerical control machine instructions; and

machining the airfoil spar surface based on the modified numerical control machine instructions.

15. The method of claim 14 further comprising

smoothing the electronic curve function model based on the comparison, wherein modifying numerical control machine instructions for machining the airfoil spar surface comprises modifying numerical control machine instructions based on the smoothed electronic curve function model.

16. The method of claim 14 further comprising

casting an airfoil spar including a plurality of pedestals in which the distal ends of the pedestals define the airfoil spar surface;

and

covering the distal ends of the pedestals with one or more coversheets.

17. The method of claim 16 in which the machining comprises machining about 0.001 to 0.002 inch from the airfoil spar surface.