Method and control system for generating machine tool control data

• US 20030171841A1
• Filed: 04/02/2003
• Published: 09/11/2003
• Est. Priority Date: 09/14/2000
• Status: Active Grant

• Current Assignee: Airbus Operations Limited (Airbus SE)
• Original Assignee: Airbus Operations Limited (Airbus SE)
• Inventors: Wilson, Christopher N.R., Banks, Stephen A, Williams, Ian P, Lloyd, Robert J, Porter, Stephen P
• Granted Patent: US 8,005,567 B2
• Time in Patent Office: Days
• US Class Current: 700/179
• 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 2219/32128 Gui graphical user interface
• CPC Class Codes: G05B 2219/35053 IGES initial graphics exchange specification
• CPC Class Codes: G05B 2219/35082 Product, feature based modeling, geometric and engineering info
• CPC Class Codes: G05B 2219/35095 Features library
• CPC Class Codes: G05B 2219/36001 File format, initital graphics exchange specification, iges standard
• CPC Class Codes: Y02P 90/02 Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]

Abstract

A control system (41) comprises a control program (42) which accesses a stored database (43) holding a predefined set of rules for performing predetermined machine tool operations, from which rules computer instructions can be derived for controlling an NC machine tool. A solid model (44) of a component to be manufactured is input to the control program (42). The solid model (44) is in the form of a computer model programmed using the International Geometry Export Standard (IGES). In operation, the control program (42) performs a feature recognition operation on the IGES data to identify geometric features present in the solid model (44). Having identified the geometric features present, the control program (42) uses the set of rules in the database (43) to generate control data in the form of a composite set of computer instructions for working the features of the component represented in the solid model (44).

Claims

1. A method of generating control data for a numerically-controlled (NC) machine tool, the method comprising:

providing a predefined set of rules for performing predetermined machine tool operations, from which rules computer instructions can be derived for controlling the NC machine tool;

providing a computer model representing a component to be worked by the machine tool, the computer model including information relating to geometric features of the component;

automatically identifying, from the computer model, geometric features of the component, and automatically identifying one or more of the predetermined machine tool operations suitable for working the identified features of the component; and

using the set of rules associated with the identified machine tool operations to generate control data in the form of a composite set of computer instructions for working the component represented in the computer model.

2. A method according to claim 1, wherein, in the step of providing the computer model, a three-dimensional solid model specifying geometric features of the component is provided.

3. A method according to claim 2, wherein, in the step of providing the computer model, a three-dimensional component description is acquired from a computer-aided design (CAD) application.

4. A method according to any preceding claim, wherein the step of providing the set of rules comprises:

providing a database of geometric features, each feature being assigned to one or more machine tool operations capable of working that respective feature; and

providing a set of selection criteria for performing each machine tool operation, the step of generating a composite set of computer instructions comprising;

matching each feature identified from the computer model with those specified in the database; and

selecting a suitable machine tool operation for the or each feature based on analysis of the selection criteria.

5. A method according to claim 4, wherein the step of providing the set of selection criteria comprises:

assigning sub-rules to one or more of the machine tool operations, the sub-rules specifying conditions for selecting the or each machine tool operation depending on the geometric feature identified in the computer model.

6. A method according to claim 5, wherein the step of providing the set of selection criteria further comprises:

assigning sub-rules to one or more of the machine tool operations, the sub-rules specifying further conditions for selecting the or each machine tool operation depending on the relative positions of a plurality of geometric features identified in the computer model.

7. A method according to any of claims 4 to 6, wherein, in the step of generating a composite set of computer instructions, the instructions specify a suitable toolpath for the or each selected machine tool operation, the step of generating a composite set of computer instructions further comprising devising a suitable machine tool operation and toolpath strategy for working the whole component.

8. A method according to any preceding claim, wherein the computer model represents a first component for assembly to one or more further components, the computer model including information relating to the geometric position of one or more assembly points of the first component.

9. A method according to claim 8, wherein the computer model represents a first component for riveting to a second component, the computer model including information relating to the geometric position of one or more riveting points in the first component, the generated set of computer instructions being NC instructions for performing a riveting operation at the riveting points specified in the computer model.

10. A method according to claim 8 or claim 9, wherein the computer model is representative of an aircraft wing stringer.

11. A method according to any of claims 8 to 10, wherein, in the step of providing the computer model, the geometric features included in the model relate to the distance between assembly points on the first component.

12. A method according to any of claims 1 to 7, wherein a computer model representing a component to be produced from a blank is provided, the computer model specifying the desired shape or configuration of the component, the generated set of computer instructions being NC instructions for forming the component from the blank.

13. A method according to claim 11 when appended to any of claims 5 to 7, wherein the step of providing the set of selection criteria further comprises assigning sub-rules to one or more of the machine tool operations for determining an appropriate rate or speed of machine tool operation depending on the material of the blank.

14. A method according to claim 12 or claim 13, wherein, in the step of providing the computer model, the geometric features included in the model relate to one of more of a recess, hole or protrusion.

15. A method according to any preceding claim, wherein the rules relate to one or more of drilling, milling, cutting, turning or riveting operations.

16. A method according to any preceding claim, wherein the computer model is representative of an aircraft component.

17. A method according to claim 16, wherein the computer model is representative of a wing stiffener.

18. A computer program stored on a computer usable medium, the computer program comprising computer-readable instructions for causing the computer to execute the steps of a method according to any preceding claim.

20. A method of manufacturing a component using a numerically-controlled machine tool, including generating control data for a machine tool in a manner according to any of claims 1 to 17.

19. A control system for a numerically-controlled (NC) machine tool, the control system comprising:

a memory storing a predefined set of rules for performing predetermined machine tool operations, from which rules computer instructions can be derived for controlling the NC machine tool; and

an application program for analysing an inputted computer model representing a component to be worked by the machine tool, the application program being configured (i) automatically to analyse and identify geometric features of the component in the computer model, (ii) to identify one or more of the predetermined machine tool operations suitable for working the identified features of the component; and

(iii) to generate a composite set of computer instructions on the basis of the rules associated with the identified machine tool operations, the composite set of computer instructions being suitable for working the component represented in the computer model.

21. A method of generating control data for a numerically-controlled (NC) machine tool, substantially as hereinbefore described with reference to the accompanying drawings.

22. A control system for a numerically-controlled (NC) machine tool, substantially as hereinbefore shown and described with reference to the accompanying drawings.