Tolerance Synthesis Relationship between Geometrical Tolerancing and Product Function

1
Tolerance Synthesis Relationship between
Geometrical Tolerancing and Product Function

• Irfan A Manarvi
• Prof. Neal P Juster

DMEM, CAD Centre University of Strathclyde
2
Contents

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

3
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

4
Tolerance Synthesis Model
Mechanical drawing or CAD File with Nominal
dimensions
Tolerance Designer
Design Development
Methods Techniques

• Management priorities
• Customer specification
• Design
• Manufacturing
• Assembly
• Material
• Quality
• Cost
• Dimensioning standards
• Experience
• Tolerance Vs. Function

• Representation
• Optimization
• Design
• Manufacturing
• Assembly
• Quality
• Cost
• Function
• Statistics and Probability
• Simulation methods

Tolerance Synthesis Process
Allocate Tolerances
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Management
Cost
Critical criteria
Cost
Function
Critical Tolerance
Function
Specifications
Design Analysis,
Useful life
Reliability
Experience
Market trends
Designer
Customer
Manufacturer
Quality
Tolerance Designer
Cost
Accuracy
Machines

• Experience
• Specific type of tolerance
• Mathematical
• theories
• Standards
• Literature
• Information

Time
Assembly
Materials
Sequence
Cost
Cost
Properties
Critical dimension
Critical properties
Interchangeability
Established variation
Function
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Software development for Tolerance synthesis
Customer
Tool Box
Management
Actions
Verify Parameters

• Experience
• Specific type of tolerance
• Mathematical theories
• Standards
• Literature
• Information

Designer

• Classify product
• Evaluate Tolerance
• Allocate Tolerance

• Function
• Cost
• Manufacturing
• Assembly
• Quality
• Management

Tolerance Designer
Manufacturer
Materials
Assembly
Quality
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Software Menu Structure
Information Databases
Manufacturer
Manufacturing process

• Determine machine. tooling, tools accuracy

Quality
Quality critera

• Inspection machine. tooling, tools accuracy
• Tolerance

Materials

• Material property which may influence tolerance

Assembly

• Best asssembly path
• Assemly tooling tolerance

8
Industrial collaboration possibilities
Applications
BR 710
Fuel Metering
BR 715
Air valves
Speciality valves
EJ 200
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Industry Market share (1)
Engine Types
Aircraft Types
Products
User Companies
Hydromechanical Engine control
06
23
49
Pumps
02
09
04
Servo valves
15 and more
No Information
Not Applicable
02
Actuators
03
05 and more
Air valves
03
02
06 or more
06
Propeller Governers
25 or more
17 or more
176 or more
32
94 or more
Total
Users of Aircraft
Unlimited
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Aerospace Market share (2)
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Research Application Example Governors for Gas
Engines
PG-PL

• PSG

• Oil Pressure control
• Speed stability
• Fuel Flow Control

• Speed Control
• Signal pressure
• Frequency selection

Evaluate influence of Variation of individual
components features on Function
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Methodology
Phase I 16 Weeks
Review
Investigate Features
Identify Application
Function relation
Mathematical Framework
2
4
2
4
4
Total time 64 Weeks
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Contributions From Company and Researcher

• Researcher
• Review Tolerancing Practices, Identify research
  applications and Formulate Mathematical and
  Analytical Framework
• Data collection and compilation
• Data Analysis and Formulate standard relations of
  Function Vs tolerances

• Company
• Designate Local Supervisor
• Providing access to design drawings, Measurement
  data, Testing data or any other technical support
• Coordination of Research
• Administrative support

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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

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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