Tolerance Synthesis “ Relationship between Geometrical Tolerancing and Product Function ” Irfan A Manarvi Prof. Neal P Juster DMEM, CAD Centre University of Strathclyde

Contents Contents u Introduction to research project u Tolerance Synthesis Model u Software development for tolerance synthesis u Software Menu Structure u Industrial collaboration possibilities u Industry Market share u Research application example u Methodology u Contributions from Industrial Company and researcher u Deliverables to a Company u Conclusions

Introduction to Research Project Aim : To establish Relationship between product function and geometric variation Nature : Theoretical & Experimental :- Collaborating with Industry or Designing a Test Rig for specific application Using Computational Fluid Dynamics (CFD) for modelling and simulation product and function

Mechanical drawing or CAD File with Nominal dimensions Tolerance Designer  Management priorities  Customer specification  Design  Manufacturing  Assembly  Material  Quality  Cost  Dimensioning standards  Experience  Tolerance Vs. Function Design & Development Methods & Techniques  Representation  Optimization Design Manufacturing Assembly Quality Cost Function  Statistics and Probability  Simulation methods Tolerance Synthesis Process Allocate Tolerances Tolerance Synthesis Model

Management Designer Quality Customer Specifications Reliability Market trends Cost Accuracy Machines Time Assembly Sequence Critical dimension Interchangeability Materials Properties Critical properties Established variation Manufacturer Process Tooling No of parts Machines Skill level Critical criteria Design Analysis, Critical Tolerance Experience Useful life Cost Function Experience Specific type of tolerance Mathematical theories Standards Literature Information Cost Tolerance Designer

Customer Management Designer Manufacturer Materials Quality Assembly Tolerance Designer Experience Specific type of tolerance Mathematical theories Standards Literature Information Function Cost Manufacturing Assembly Quality Management Classify product Evaluate Tolerance Allocate Tolerance Tool Box Actions Verify Parameters Software development for Tolerance synthesis

Manufacturing process Determine machine. tooling, tools accuracy Quality critera Inspection machine. tooling, tools accuracy Tolerance Material property which may influence tolerance Quality Best asssembly path Assemly tooling tolerance Establish relationship of customer Parameter to critical di mensions Quantify change in customer Parameter w.r.t change in critical dimension Acceptable variation in Parameter. Evaluate limit of useful life, reliability maintenance and any other specific factor on dimensional tolerance Critical Parameter Function/cost/ any other Customer Assembly Materials Manufacturer Information Databases Establish nominal dimensions and Identify all features Allocate variable designators Indicate misssing dimension Specify suitable datums Identify critical and non critical feature Mark critical /non critical feature Mark non critical feature whose tolerance influence critical features tolerance Designer Types of tolerances Tolerancing criteria MMC/LMC/RFS Bonus tolerancing Applicable tolerances Study and analyse drawing Software Menu Structure

Fuel Metering Speciality valves Air valves BR 715 BR 710 EJ 200 Applications Industrial collaboration possibilities

Industry Market share (1) Products User Companies Aircraft Types Engine Types Fuel Metering units Hydromechanical Engine control Fuel Nozzles Pumps Speciality Valves Servo valves No Information Not Applicable 15 and more Actuators and more Propeller Governers or more Air valves or more 17 or more Total 3294 or more 176 or more Users of Aircraft Unlimited

Aerospace Market share (2)

Research Application Example: Governors for Gas Engines PSG PG-PL  Speed Control  Signal pressure  Frequency selection  Oil Pressure control  Speed stability  Fuel Flow Control Evaluate influence of Variation of individual components features on Function

Phase II 22 Weeks Identify Features 6 Testing 2 Measurements 6 Analysis 2 Compile 6 Total time = 64 Weeks Phase I 16 Weeks Review 2 4 Investigate Features 24 4 Identify Application Function relation Mathematical Framework Phase III 26 Weeks Data Review 6 Comparing performance 4 Application of Analytical tools VerifyStandardise Methodology

Contributions From Company and Researcher Company u Designate Local Supervisor u Providing access to design drawings, Measurement data, Testing data or any other technical support u Coordination of Research u Administrative support Researcher u Review Tolerancing Practices, Identify research applications and Formulate Mathematical and Analytical Framework u Data collection and compilation u Data Analysis and Formulate standard relations of Function Vs tolerances

Deliverables to A Company Research analysis data covering standard relationships of one or more function vs dimensional tolerances. Database of Knowledge for all customers Research publications for International Journals drafted by researcher and reviewed by Academic and company supervisor A standard tolerance synthesis process customised to the needs of a company

Conclusions Limited literature is held on the research area The nature of research is applied and is expected to be of a lot of Commercial value for Industry. Its findings are expected to be a source of reference for other researchers