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A HOLISTIC APPROACH TO QUALITY MANAGEMENT FOR COMPOSITE FORMING PROCESSES
June 2016
Dr. Farbod Nezami
28.09.2017 | 2Fuhr | Nezami | Schierle
Composite Forming: Reliable, fast, effective, but…
Sour
ce: A
irbus
, Boe
ing,
ETZ
, Dai
mle
r
• High lot size• Cost sensible
• Complex shaped geometries• Small sectioned parts• Packaging- & design demands
Geometry Process
Fast formingprocesses
What to do aboutquality?
How can we improve the quality of preforms with an holistic quality approach?
1. Parts free of wrinkles and reduction of fiber distortions (“waviness”)2. Influencing of fiber orientation and shear angles3. Assess the resulting mechanics4. Validate our approach?
28.09.2017 | 3Fuhr | Nezami | Schierle
The Complexity of Composite Forming
• Textiles show specific forming modes and characteristics.
• Complex Geometries consisting of radii, curvature, edges.
• Formability can be influenced by Process factors too.
• These interactions define the resulting Mechanics of the structure.
Every development has to be regarded as a holistic system of all aspects
Textiles
GeometryProcess
Mechanics
28.09.2017 | 4Fuhr | Nezami | Schierle
An Holistic Quality Approach to Preforming
„Planning quality“
„Realizing quality“
„Ensuring quality“
„Analysing quality“
MethodsProcess SelectionMaterial SelectionProcess FeasibilityDraping simulation
MethodsActive manipulationAutomationTool design
MethodsOptical analysisNon-destructive testingQuality criteria
MethodsComposite FEASensitivity studiesProcess factors
Textiles & Geometry
Process
Validation
Mechanics
Definition of local quality criteria
Process optimization
Draping effects
28.09.2017 | 5Fuhr | Nezami | Schierle
Material characterization with process induced factors:Shear-Tension Coupling
BA
Membrane tensionNo wrinkles at 55°
Tension freeWrinkles at 55°
28.09.2017 | 6Fuhr | Nezami | Schierle
Material characterization with process induced factors:Fiber waviness due to interactions
Forming Limit Diagram
Fiber waviness
In-plane damage
28.09.2017 | 7Fuhr | Nezami | Schierle
Definition of a Forming Limit Diagram for Interaction Defects
Textiles
GeometryProcess
28.09.2017 | 8Fuhr | Nezami | Schierle
Recent developments in prediction of fiber waviness
• The first chapter of the quality approach showed us that:– There is an interlink between tension (process) and wrinkling (textile)– There is an interaction of layers towards each other which can cause fiber waviness
• Draping simulation can be used to investigate the risk of wrinkles and fiber waviness
28.09.2017 | 9Fuhr | Nezami | Schierle
An Holistic Quality Approach to Preforming
„Planning quality“
„Realizing quality“
„Ensuring quality“
„Analysing quality“
MethodsProcess SelectionMaterial SelectionProcess Feasibility
MethodsActive manipulationAutomationTool design
MethodsOptical analysisNon-destructive testingQuality criteria
MethodsComposite FEASensitivity studiesProcess factors
Textiles & Geometry
Process
Validation
Mechanics
Definition of local quality criteria
Process optimization
Draping effects
28.09.2017 | 10Fuhr | Nezami | Schierle
Integration of forming defects of composite forming to FEA analysis
Nezami, Fuhr, Schierle, Cherif, Middendorf: Holistic development of high quality composite parts based on automated preforming in JEC magazine no. 103, March 2016, Special JEC World
3D Plot of fiber orientationdue to forming FEA modelling Analysis of forming effects
Draping simulation
28.09.2017 | 11Fuhr | Nezami | Schierle
An Holistic Quality Approach to Preforming
„Planning quality“
„Realizing quality“
„Ensuring quality“
„Analysing quality“
MethodsProcess SelectionMaterial SelectionProcess Feasibility
MethodsActive manipulationAutomationTool design
MethodsOptical analysisNon-destructive testingQuality criteria
MethodsComposite FEASensitivity studiesProcess factors
Textiles & Geometry
Process
Validation
Mechanics
Definition of local quality criteria
Process optimization
Draping effects
28.09.2017 | 12Fuhr | Nezami | Schierle
Integration of previous steps into process development
Reduction of interaction force and fiber waviness by oscillations
Mechanical actuatorsReduction of wrinkling due to local application
of tensile forces
28.09.2017 | 13Fuhr | Nezami | Schierle
Application: Mercedes-Benz AMG Backlid
Cut-out optimization and ply clamping
Transfer to active interlayers
Multilayer draping with activeinterlayers
Orientation 0°
Orientation 45°
Clamping
Cut / Dart
Clamping
Different material draw-in and
clampingnecessary!
0/90° top layer
Homogenous Blank Holder Force
Ply-specific clamping
Piezo actuatorsfor oscillations
• Reduction of the size ofwrinkles by 81,5%
• Complete suppressionof interaction baseddefects
28.09.2017 | 14Fuhr | Nezami | Schierle
An Holistic Quality Approach to Preforming
„Planning quality“
„Realizing quality“
„Ensuring quality“
„Analysing quality“
MethodsProcess SelectionMaterial SelectionProcess Feasibility
MethodsActive manipulationAutomationTool design
MethodsOptical analysisNon-destructive testingQuality criteria
MethodsComposite FEASensitivity studiesProcess factors
Textiles & Geometry
Process
Validation
Mechanics
Definition of local quality criteria
Process optimization
Draping effects
28.09.2017 | 15Fuhr | Nezami | Schierle
Validation and Assessment of Measures by Optical Fiber Measurement System
1Local AnalysisDefinition of critical spots
2Definition of robot coordinates
Analysis of- Fiber orientations- Gaps- Validation of draping simulation
4
VALIDATION &ASSESSMENT
3 Capturing
28.09.2017 | 16Fuhr | Nezami | Schierle
Conclusions
• To increase quality of parts being produced by composite forming an holistic approach is necessaryas interlinks of domains drive overall quality
• Early stage material characterization can help to identify dominant quality drivers• In preforming it was found that wrinkles can be suppressed by local tensioning, but risk of
interaction defects like fiber waviness can increase hereby. Therefore reduction of normal contactforces is necessary.
• This was realized by the utilization of active interlayers which can actively control tensioning andreduce interlayer friction by oscillations
• Optical fiber measurement systems were applied to validate the results of draping simulations andassess the quality improvement due to process improvements
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