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12/15/2015
1
• Build parameter adjustment
• Build orientation
• Powder characteristics
• Post processing
Published research Why has AM surface been measured?
• Build parameter adjustment
• Build orientation
• Powder characteristics
• Post processing
Function?
Published research Why has AM surface been measured?
12/15/2015
2
Focus variation [11%]
Confocal microscopy [11%]
SEM [11%]
Coherence scanning interferometry [8%]
Optical microscopy [7%]
Chromatic confocal [4%]
Conoscopic holography [4%]
(AFM [4%])
XCT [4%]
Raman spectrometer [4%]
(Review of 100+ publications)
Contact areal [4%] [1] Non-contact areal Contact stylus [40%]
Published research Measurement method
Microgeometry capture using an elastomeric sensor
Johnson, Micah K, Cole, Forrester, Raj, Alvin and Adelson, Edward H 2011 1.
Profile measurement (ISO 4287:1998)
• Ra (Arithmetic mean deviation of the assessed profile) [41%]
• Rq (Root mean square deviation of the assessed profile [std. dev.]) [18%]
• Rz (Maximum height of profile [within sampling length]) [12%]
• Rt (Total height of profile [within evaluation length]) [6%]
• Rsk (Skewness of the assessed profile) [6%]
• Rku (Kurtosis of the assessed profile) [6%]
• Material ratio curve of the profile (Abbott Firestone curve) [6%]
Published research Surface texture parameters
12/15/2015
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Same Ra value
Pit or scratch? [1]
Published research Surface texture parameters
Why use areal surface texture measurement?
DMAC Meeting, University of Huddersfield. L. Blunt. 2006 1.
Areal measurements (ISO 25178-2:2012)
• Sa (Arithmetic mean height of the scale-limited surface) [12%]
• Sq (Root mean square height of the scale-limited surface) [6%]
• Sal (Autocorrelation length) [6%]
• Str (Texture aspect ratio) [6%]
• Std (Texture direction of the scale-limited surface) [6%]
• Sdr (Developed interfacial area ratio of the scale-limited surface) [6%]
• Sk (Core height) [6%]
• Spk(Reduced peak height) [6%]
• Svk (Reduced dale height) [6%]
• Smr2 (Areal material ratio [dales]) [6%]
• Vmp (Peak material volume of the scale-limited surface) [6%]
• Vmc (Core material volume of the scale-limited surface) [6%]
• Vvv (Core void volume of the scale-limited surface) [6%]
Published research Surface texture parameters
12/15/2015
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Areal measurements (ISO 25178-2:2012)
• Sa (Arithmetic mean height of the scale-limited surface) [12%]
• Sq (Root mean square height of the scale-limited surface) [6%]
• Sal (Autocorrelation length) [6%]
• Str (Texture aspect ratio) [6%]
• Std (Texture direction of the scale-limited surface) [6%]
• Sdr (Developed interfacial area ratio of the scale-limited surface) [6%]
• Sk (Core height) [6%]
• Spk(Reduced peak height) [6%]
• Svk (Reduced dale height) [6%]
• Smr2 (Areal material ratio [dales]) [6%]
• Vmp (Peak material volume of the scale-limited surface) [6%]
• Vmc (Core material volume of the scale-limited surface) [6%]
• Vvv (Core void volume of the scale-limited surface) [6%]
Published research Surface texture parameters
Scale of interest?
12/15/2015
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Scale of interest?
Dune buggy suspension?
Cut-off 500 m
Arithmetic mean height 10 m?
Scale of interest?
Dune buggy suspension?
Cut-off 500 m
Arithmetic mean height 10 m?
Wind-ripple generation?
Cut-off 0.2 m
Arithmetic mean height 2 cm?
12/15/2015
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Scale of interest?
Dune buggy suspension?
Cut-off 500 m
Arithmetic mean height 10 m?
Wind-ripple generation?
Cut-off 0.2 m
Arithmetic mean height 2 cm?
Abrasiveness?
Cut-off 0.2 cm
Arithmetic mean height 0.1 mm?
Scale of interest?
Dune buggy suspension?
Cut-off 500 m
Arithmetic mean height 10 m?
Wind-ripple generation?
Cut-off 0.2 m
Arithmetic mean height 2 cm?
Abrasiveness?
Cut-off 0.2 cm
Arithmetic mean height 0.1 mm?
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Scale of interest?
DEFECT?
Scale of interest?
12/15/2015
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Scale of interest?
µm
Scale of interest?
km
12/15/2015
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New Horizons mission
NASA/JHUAPL/SwRI SEM image Ti6Al4V
Scale of interest?
SEM image AlSi10Mg
Scale of interest?
12/15/2015
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SEM image AlSi10Mg
Scale of interest?
SEM image AlSi10Mg
Scale of interest?
12/15/2015
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SEM image AlSi10Mg
Scale of interest?
Importance of AM surface topography
Defining a “good” surface based on functionality
12/15/2015
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Importance of AM surface topography
Defining a “good” surface based on functionality
Linking a “good” surface to suitable surface inspection parameters
Importance of AM surface topography
Defining a “good” surface based on functionality
Linking a “good” surface to suitable surface inspection parameters
Linking surface inspection parameters to AM build variables
12/15/2015
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Importance of AM surface topography
Defining a “good” surface based on functionality
Linking a “good” surface to suitable surface inspection parameters
Linking surface inspection parameters to AM build variables
Defining and standardising AM surface inspection parameters
SEM image AlSi10Mg
Metal powder bed fusion AM surface
12/15/2015
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• Cube 10 mm per side • 100 µm powder thickness
• 100 µm line spacing
Approximate percentage of total surface area produced during the manufacturing process remaining as outside surface on
completion:
3%
Importance of AM surface topography
Embedded surface example (powder bed fusion)
Surface <-> porosity?
Reconstruction from xCT showing porosity analysis
12/15/2015
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Which surface? Feature analysis -motif analysis and segmentation
AlSi10Mg sample, Renishaw AM250, Alicona Infinite Focus G4
• Extract “outcrops / peaks”
• Analyse underlying surface
• Analyse “outcrops / peaks”
• Process control?
Re-entrant features?
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