Industrial Background Research Problematic Method Overview Key Characteristics Assembly Sequence Conclusion ADCATS Conference - 14/15 June 2001 Brigham Young University - Provo UT Benoît Marguet E.A.D.S Corporate Research Center - France Tel : Method & Tools for Geometric Variation Management

Industrial Background (I) Industrial Background (I) Complex Product Extensive manufacturing organisation Structural Assembly High number of parts Various Assembly levels Aircraft Assembly Line Car Assembly Line Assembly Conversion Material 45% 30% 25% Aircraft manufacturing cost : } Importance of Assembly Cost Need to manage product’s assemblability

Design ManufacturingIntegration Section assembly System installations Aircraft assembly System tests Section architecture Design Tooling Design Definition Definition Drawings Tooling Definition Manufacturing Manufacturing of piece parts Assembly of workpackages Manufacturing of assembly toolings Airbus or Suppliers Airbus Assembly principles Industrial Background (II) Industrial Background (II) Development cycle of aircraft sections Need to manage product’s assemblability as soon as possible during the development cycle

Problematic Sub-section assembly operation How to improve product’s assemblability ? By reducing assembly failures Parts reduction Geometric variation management Where to manage product variations ? How to control effect of variations on functional requirements? Geometric Variation Management Method (GEOVAR) How to reduce assembly failures ?

Method Overview Design Principle Product Structure j1 j2 j4 j6 j5 j3 j7 j8 Key Characteristics Assembly Sequence Manufacturing Capabilities Part Specifications GEOVAR : From product’s Key Characteristics to part’s specifications

Product Key Characteristics (I) Concepts Functional requirements & related geometrical characteristics are too numerous on complex product in order to manage all of them. Need to focus attention of designers & manufacturers on what is really important for the product. Definition “Product Key Characteristics are the geometrical features of component or sub-component whose variation has the greatest influence on the product function”. Functional Requirement Identification (1) Geometrical Requirement Identification (2) Product Key Characteristics Identification (3) Identification Process KC

1 Product Key Characteristics (II) Functional Requirement Identification Inputs : Preliminary Design, Product Structure Outputs : Technical Requirements, Product Constraints Tools : FAST Diagram, MIMIO

Geometrical Requirements Identification Inputs : Technical Requirements, Product Constraints Outputs : Geometrical Requirements (nominal value and tolerance level) Tools : QFD Matrix WHAT Subjective customer preferences HOW Objective engineering specification Relation Matrix How Much Tolerance Specification Correlation Matrix QFD Matrix Seat Rail Alignment Geometrical Requirements 2 Product Key Characteristics (III)

Key Characteristics Identification Inputs : Geometrical Requirements, Assembly Process Outputs : Hierarchical requirement level, PKCs Tools : Risk Analysis PKC 3 Product Key Characteristics (IV)

Benefits of exercise Defines what is, and is not, important for the variation management. Targets areas/features that need to be measured and monitored (through SPC). Helps designers to distribute tolerances & select appropriate datums. Also Clarifies of Design intent. Promotes Concurrent Engineering. Truly links Design, performance, manufacturing. Product Key Characteristics (V)

Assembly Sequence (I) Problematic Various assembly sequences are available for a single product. All assembly sequence will have a different quality cost for the product. Question What assembly sequence will minimize impact of part’s variation on PKCs ? Assembly Sequence #1 Assembly Sequence #2

Assembly Sequence (II) Concepts Assembly Sequence analysis focus on PKCs (for variation impact). Impact of part variation on PKCs depends on assembly sequence choice. Selection of assembly sequence is made very early in the design cycle. Mate & Contact Identification (1) Propagation Chain Identification (2) Worst Case & Statistical Tolerance Analysis (3) Analysis Process Goal To analyze as soon as possible during the design cycle, all admissible assembly sequences in order to select the optimal one.

Mate & Contact Identification (I) Definition (D.E Whitney) A mate is an assembly link that establishes constraints and dimensional relationships between part. A contact is an assembly link that supports and fastens the part once it is located. Property Mate and Contact are related to the assembly sequence. Geometrical variations flow from part to part through mates only. Benefice Easy to represent on a graph Tool for variation propagation analysis. Assembly Sequence (III) Stringer Cleat Pannel M M M M M M C C C C Mate Contact M C 1

Assembly Sequence (IV) Assembly Sequence #1 Lower Floor Lower Shell Upper Shell Left Upper Shell Right Tool Door Upper Floor Mate & Contact Identification (II) Tools : Assembly Oriented Graph. Assembly surfaces Mate Contact PKC 1 KC AOG is a directed acyclic graphical representation of an assembly given a picture of the location dependencies of parts and surfaces. Each node represents assembly surface. Oriented arcs represent mates between two assembly surfaces. The arrow points on the positioned component. Oriented dotted arcs represent contacts between two assembly surfaces and dotted line represents geometrical conditions

Assembly Sequence (V) Propagation Chain Identification Inputs : Assembly Oriented Graph, Key Characteristics Outputs : Qualitative Assembly Sequence Analysis Tools : Propagation Chain Definition A propagation chain is defined by all the mates necessary in order to perform a Product Key Characteristics. Property PKCs quality will be related to the length of the propagation chain. Lower Floor Lower Shell Upper Shell Left Upper Shell Right Tool Door Upper Floor 2 Propagation Chain

Assembly Sequence (VI) Tolerance Analysis Inputs : Manufacturing Capabilities,Assembly Process, Geometric Characteristics, PKCs. Outputs : Quantitative Assembly Sequence Analysis. Tools – Available commercial software (Valisys, CeTol, 3DCS). – In house development (AnaTole). 3

Assembly Sequence (VI) AnaTole Software In house development based on TTRS, Variation Model (EADS C.C.R) and Open Cascade (EADS MatraDatavision). Benefits : – Easy to use without a deep knowledge of CAD system. – Very close to manufacturing and Design process. – Over-Constraint Detection and Analysis. – Statistical & Worst Case Tolerance Analysis. – Useable as soon as possible in the design cycle (wireframe geometry only).

Method Summary 1 To identify the major functional requirements 1 To identify the major functional requirements 2 To translate the functional requirements into geometrical requirement 2 To translate the functional requirements into geometrical requirement 3 To identify the product’s Key Characteristics 3 To identify the product’s Key Characteristics 4 To select an admissible assembly sequence 4 To select an admissible assembly sequence Yes To choose another assembly sequence To change design principle 5 To select the Mate / Contact assembly links 5 To select the Mate / Contact assembly links 6 To analyse the assembly sequence 6 To analyse the assembly sequence Are all geometrical conditions fulfill ? Are all geometrical conditions fulfill ? Is it possible to choose another assembly sequence ? Is it possible to choose another assembly sequence ? Is it possible to improve the manufacturing capabilities Is it possible to improve the manufacturing capabilities To improve Manufacturing capabilities Assembly sequence validated + tolerance specification Yes No

Conclusion & Future prospect Need to manage tolerance from the functional requirement to ISO specification based on : Product Key Characteristics Assembly processes Manufacturing Capabilities Definition & Deployment of a Variation Management Method Useful for complex product like aircraft. Used as soon as possible during the design process. Allowing to select the optimal assembly sequence. On going Works Take into account flexible parts in the method Automatic assembly sequence planning & analysis. Wide deployment of the method.