mask projection micro stereolithography
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Mask Projection Micro StereolithographyHessel Maalderink
Precisiebeurs, woensdag 30 November 2011
Stereolithography
Courtesy CustomPartNet
Micro Stereo Lithography
Voxel size
Scal
e
Laser (2 photon)
Laser
Mask projection
nm μm mmCourtesy Laser Zentrum Hannover
Micro Stereo Lithography
Applications:PrototypingMasterRapid Manufacturing
Fields of operation:Medical DevicesElectronics / TelecomSensorsMicro fluidic systemsMechanical componentsMould makingJewelry
Courtesy RapidShape
DLP machine principle Spindle
Load cell
Platform
Reservoir
Mirror
Steppermotor
Projector
Shutter
Micro Stereo Lithography
3D Cad file STL file BitmapsTo project
Work flow
μSLA part
Introduction to micro stereolithography
Glass
Light curable resinCured Resin
Z-stage
DLP Projector
Micro stereolithography
Glass
Light curable resinCured Resin
Z-stage
DLP Projector
Micro stereolithography
Glass
Light curable resinCured Resin
Z-stage
DLP Projector
Micro stereolithography
Glass
Light curable resinCured Resin
Z-stage
DLP Projector
Micro stereolithography
Glass
Light curable resinCured Resin
Z-stage
DLP Projector
Micro stereolithography
Glass
Light curable resinCured Resin
Z-stage
DLP Projector
Force feedback mechanism
Micro Stereo Lithography
The Lepus® System
Closed LoopForce feedback
Layertime reduced to 3 seconds
Projecion: DLP, blueMotion Control: Force Feedback loopResolution: 1920 x 1080 pixelsPixel size 50 – 80 μmLayer thickness: 25 – 100 μmBuild envelope: 96x54x120 mm .. 154x87x120 mmBuild speed: 50 μm : up to 45 mm per hour
100 μm : up to 90 mm per hour
Process prototyping
Process prototypingProjecion: DLP, UVMotion Control: Force Feedback loopResolution: 1024 x 768 pixelsPixel size 4 μmLayer thickness: 5 – 25 μmBuild envelope: 40x30mm (4x3 mm)Stepping: Yes
µ SLADevelopment of custom additive manufacturing
systems, in a B2B consortium with industrial partners
Dental
Hearing aid
Jewelry
Courtesy RapidShape
Hessel Maalderink Confidential
16
Geometric part quality influences
Pressure build-up
Support
LayersOptimizations: pixel size, layer thickness, design
1. LMT inherent limitations
2. Equipment quality
3. Material behavior
Hessel Maalderink Confidential
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Geometric part quality influences
Optimizations: equipment design, optical corrections
Z stagealignmentZ accuracyXY accuracy
Light engineAlignmentStabilityPicture quality
1. LMT inherent limitations
2. Equipment quality
3. Material behavior
GeometricSize & Aspect ratioTrapezoid & Cushion
Non geometricFocusLense flare, reflectionsIntensity variations (local)
Hessel Maalderink Confidential
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Geometric part quality influences
Optimizations: filled matrerials, smart illumination
1. LMT inherent limitations
2. Equipment quality
3. Material behavior
Through-cure (Z-bonus)Shrinkage
Curing shrinkageThermal shrinkage
Results in: - XY error- interlayer tension =>curl
Hessel Maalderink Confidential
19
Smart correctionsOptical correction in slicerBoundary offset
Smart iIllumination strategyGrey pixels
Boundary improvementTension reduction (difference in contour and inner illumination)
Hessel Maalderink Confidential
20
Geometric part quality influences
Geometric part quality is influenced by many factors.Special test geometries are needed to isolate them.
Benchmark Part
Angle’sHoles,Small featuresAccuracyInternal channelsZ-bonus…
Micro Stereo Lithography
Benchmark Part
Small features
Micro stereolithography - examples
Hearing aids
Courtesy of Widex
Layer thickness: 0.01 mm
© TNO © TNO
Total Height: 2,7 mm
Micro stereolithography - examples
• Digital Light Processing – Research.• Stepping to build larger parts with High Resolution.
© TNO © TNO
Micro stereolithography - examples
Micro fluidic structure
Courtesy D-Mec
Micro stereolithography - examples
Ongoing research: Processing highly filled material
Viscosity modification through dispersing agents
1,0E+02
1,0E+03
1,0E+04
1,0E+05
1,0E+06
1 10 100
Shear rate (1/s)
Visc
osity
(mPa
.s)
75wt% no disp
74 wt %
80 wt %
87 wt %
89 wt %
90 wt %
Optical characteristicsLight scattering due to ceramic particles influences spatial resolution of the uSLA process
Important parametersParticle size distributionRefractive index of ceramic particleRefractive index of photopolymerAbsorption coefficient of ceramic particle
First results
Al2O3 SiC
High Filled µSLADevelopment of additive manufacturing systems for high
filled materials, with partners in industry and research.
Next Step
Magnetic
Metals
Piëzo
Biomaterial
Ceramics
Organic
ZrO2
AlN
Al2O3
Ceramics
SiO2
SiC
31
Micro Stereo Lithography
Questions
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