Theme III: Process Planning and Validation
Theme Objective:• To develop advanced geometric computing
algorithms and novel closed-loop machining platforms to generate and validate process plans for producing quality machined parts.
Sub-Themes:IIIA. Cutter-Part Engagement Geometry DeterminationIIIB. On-line Process Re-planningIIIC. Off-line Process/Part Validation
Theme IVModular Machine Tool
Controls & Sensors
Theme IIMachine Tool Error Models
Role of Theme III in Overall Network
IIIACutter-Part Engagement Geometry Determination
IIICOff-line Process/Part
Validation
Theme VVirtual Machining
System
Process Plan
Machined Part
IIIBOn-line Process
Re-planning
Theme IMaterials &
Machining Models
Theme III Projects
• Theme Researchers: H.Y. Feng (UBC), P.H. Gu (Calgary), A.D. Spence (McMaster)
• Collaborating Network Researchers: Y. Altintas (UBC), P. Koshy (McMaster)
• Academic Collaborators: R. Fleisig (McMaster), D.Y. Xue (Calgary)
• Industrial Collaborators: F.-É. Delorme, S. Engin (Pratt & Whitney Canada), M. Desnoyer (Origin International), D. McPhail (Memex Automation)
• Four Master’s and four Ph.D. students
IIIA.1: Analytical Formulation of Cutter-Part Engagement from Z-Buffer Images
• Benefits: closed-form solutions accuracy & efficiency
• Proposed Methodology:– Identify the boundary points– Reconstruct the desired piecewise smooth analytical curve
• Current Progress: one MASc to start in September 2011
IIIA.2: Rough / Semi-Finish Machining Optimization
• The originally proposed B-rep (boundary representation) scheme – not robust enough.
• Mesh-based scheme is being explored.
IIIB.1: CNC and Inspection Hardware Integration
• To develop integrated inspection and GD&T decision making at the CNC machine tool
• GD&T processing with Origin software converted to embedded system
• Integration and feedback using Memex CNC control interface
IIIB.2: Modeling and Robust Localization of Free-Form Surfaces
• To develop new modeling techniques & localization methods for precision inspection of free-form surfaces.
• Main feature: considering both the reconstructed curve/surface and its uncertainty at different locations.
Upper tolerance boundary
Lower tolerance boundary
Manufactured curve/surface
Approximated model Variation boundaries
A A
B B B
A
IIIB.3: Measurement Compensated Finish Machining
• To use inspection data to optimize heat treated / cast part finish machining tool paths.
• Tool path generation for compressor blade fillet.
IIIB.4: Surface Comparison and Tool Path Re-planning
• To determine the geometric errors, analyze the errors and develop compensation methods for tool path re-planning.– Determine magnitude and distribution of errors.– Re-program the tool paths to compensate the errors.
IIIC.3: Comprehensive Geometric Error Evaluation of Complex-Shaped Parts
• To fully automate the geometric error evaluation task of complex-shaped machined parts such as compressor, impeller, or turbine blades.
Suction Side Camber Curve
Trailing Edge
Pressure Side
Leading Edge
Suction Side Camber Curve
Trailing Edge
Pressure Side
Leading Edge
Suction Side Camber Curve
Trailing Edge
Pressure Side
Suction Side Camber Curve
Trailing Edge
Pressure Side
Leading Edge
U
Measured Actual
–3σ +3σ
Measured point
Actual curve Feasible curves
Measurement uncertainty circle
Non-linear region
Linear region
IIIC.4: Section-Specific Geometric Error Evaluation via Surface Scanning
• To enable accurate evaluation of geometric errors at specific sections of the machined free-form parts from complete surface scans.
• Current work: scanned noise reduction