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Adaptive machining. Peter Dickin Marketing Manager Delcam plc. Adaptive Machining. Accurate and efficient machining depends on knowing three things; Workpiece position Shape of initial stock Final shape to be achieved If any of these is not known then an adaptive solution is needed.
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Adaptive machining Peter Dickin Marketing Manager Delcam plc
Adaptive Machining Accurate and efficient machining depends on knowing three things; • Workpiece position • Shape of initial stock • Final shape to be achieved • If any of these is not known then an adaptive solution is needed.
Part shape Stock shape Stock position Datum Adaptive machining • Conventional machining sees a smooth workflow from CAD to inspected part • Adaptive machining uses in-process measurement to close the loop on some or all of the CADCAM process chain CAD CAM Post Process Machine Probing Inspection
Unknown stock position For many machining projects, the required stock location is difficult to achieve Aligning large parts is • Laborious • Error-prone • Time-consuming • Solution: Adapt the toolpaths to the stock position.
Unknown stock shape • Applications include • Machining from near-net-shape stock (castings, forgings etc.) • Repair of worn or damaged components or tooling • More precise finish machining after initial operations • Large tooling • Composite parts • Inspection of actual part allows machining to be adjusted on a case-by-case basis • Better accuracy • Less air cutting
Unknown Part Shape • When a part has changed from nominal during service, e.g. turbine blades distorted by heat, any repair has to match to actual surfaces instead of the nominal CAD model • When CAD data does not exist, repairs often need only to blend into existing surfaces without creating a complete new model • Overcomes inconsistencies with inaccurate assembly processes, e.g. welding
Composites applications • Reducing set-up times for large tools • Finish machining of flexible components, e.g. window holes in airframes • Drilling holes to a standard depth in an uneven surface
Overcoming distortion • Machining can cause distortion as fibres are cut • Inspection of part will indentify these errors • Extra machining operations can be carried out to give accurate parts, e.g. two-stage drilling
Background Foreplane manufactured by BAE Systems Samlesbury Foreplane measures - 2.2m x 1.1m approx Material - Formed titanium blank Process - Machining to remove sacrificial material and finish key features relative to aerofoil
Equipment Machine - Henri Line GICAMILL 24 LS/5 Type - 5-axis Size - 3.2m x 2.0m x 1.5m Controller - Fanuc CNC
Original Process • Mount on fixture • Adjust location by hand • Machine features • Turn part over • Locate and machine on 3 additional fixtures Time consuming and vulnerable to errors
New Process • Locate part on new vacuum fixture • Part overhangs fixture to machine underside without turning over • On-machine probing of part • Computerised best-fitting to locate part • Adjust machine datum to match part, rather than positioning part to match machine datum
Alignment Steps - 1 Locate part on new vacuum fixture Enter part identification details into software for audit trail
Alignment Steps -2 Run pre-defined 5-axis probing program to measure carefully selected key points
Alignment Steps - 3 Software reads the measurement results and computes best fit
Alignment Steps - 4 Software converts fit into Fanuc format to translate and rotate datum Operator checks movement is not excessive Datum shift executed on machine, followed by machining
Benefits Manufacturing time reduced by over 60%; each foreplane used to take 20-30 hours Manual rework virtually eliminated Manual set-up times dramatically reduced and now more consistent Operator variability significantly reduced Project won BAE Systems Chairman’s Award