sabafazeliportfolio2015
TRANSCRIPT
ME203: DESIGN AND MANUFACTURING — FALL 2014
YANG LAB: ORTHOPAEDIC SURGERY — SUMMER 2014 ME 101: VISUAL THINKING — WINTER 2014
CHRYSLER: DRIVER INDEPENDENCE — FALL 2014
FRAME BUILDING: BICYCLE — FALL 2012
d.school: SUMMER MAKER — SUMMER 2011
CONTENTS
V8 COFFEE TABLE
SKETCHING AND PROTOTYPE
ASSEMBLY
FINISHED AND TESTED PRODUCT
MECHANICAL PROPERTIES OF 3D-PRINTED FUNCTIONALLY GRADED SCAFFOLDS FOR TREATMENT OF LARGE SEGMENTAL BONE DEFECTS
Saba Fazeli, Yaser Shanjani, Yunzhi Peter YangDepartment of Orthopaedic Surgery, Stanford University School of Medicine
INTRODUCTION
METHODS
RESULTS
PCL / TCP COMPOSITE PREPARATION• PCL with average molecular weight (Mn) of 80,000 and density of 1.145 g/cm3
Mixed with β-TCP of particle mesh size 60 and specific surface area of 17 m2/g• Maintain an approximate ratio of 0.16g/mL of PCL/Acetone throughout.• Heat Acetone to between 53-55˚C• Melt PCL into Acetone• Mix TCP into Acetone (also 53-55˚C) in separate container• Stir TCP mixture into PCL until distributed evenly• Leave in extraction hood to evaporate Acetone• Cut material into small pieces for filament generation
RESULTS (CONT’D)RHEOLOGY
Pure PCL shear-thickens whenextruded through agiven diameter hole.For example, thefilament extruder wouldyield a 2.2mm thickfilament from a1.76mm hole. Thiseffect is reduced withβ-TCP addition.
MECHANICAL TESTING
• Uniaxial testing system
• 2 KN load cell• 5mm x 5mm x
10mm samples
CONCLUSIONS
REFERENCES
ACKNOWLEDGEMENTS
SCANNING ELECTRON MICROSCOPY
To the left, is ascanning electronmicroscope (SEM)image of thefunctionally gradedscaffold. The struts areclear, and thestructure’s porosity isevident. Note the 90˚fill pattern angle.
WATER UPTAKEAll sample types become hydrophilic after treatment with NaOH,but minute variations between different concentrations of TCPand relatively large standard deviations suggest that there aremore significant factors impacting the water uptake capacity.
The authors would like to thank the Stanford BioengineeringDepartment’s Research Experience for Undergraduates Summerprogram for providing funding for this project.
FUTURE PRODUCTPOTENTIAL
Pictured to the leftis a 5mm x 20mmcylindrical sampleprinted from 80:20PCL:TCP materialfor futuresegmental boneanimal studies.
SCAFFOLD FABRICATION• Fused Deposition Modeling• Extruder temperature at 140˚C• Extruding 1.5mm/s• 350μm strut size• 300μm layer thickness • 90˚ fill pattern• 60% porosity• Surface treated in
5M NaOH overnight
3D-printing is a versatile technology able to precisely create difficult to manufactureand near-net-shape structures with high repeatability [1]. With the freedom to adjustparameters such as material composition, external geometry and internalarchitecture (like porosity and fill pattern), 3D-printing enables the fabrication ofeffective load-bearing, biologically compatible functionally-graded scaffolds (FGS)for orthopaedic applications [2,3,4].
In this study, porous scaffolds are 3D-printed using biodegradable poly(ε-caprolactone) (PCL) and β-tricalcium phosphate (β-TCP) composite material to beutilized as load-bearing osteoconductive bone graft substitutes for treatment oflarge segmental bone defects. To predict the load bearing potential of FGSstructures with varying PCL:TCP ratio, the effect of β-TCP content on themechanical and structural properties of the scaffolds is characterized and explored.
This study explored the load-bearing potential and applicability of3D-printed biocompatible lattice structures to treating segmentalbone defects. Scaffolds include interconnected pores in bothvertical and horizontal directions as well as rough strut surfaceproviding suitable conditions for bone ingrowth and mechanicalinterlock with host bone upon implantation. Mechanicalcompression and bending tests indicated that there is a materiallimit to the strength benefits of additive β-TCP to PCL: as the β-TCP content increases, from 20% to 30% the composite materialand scaffold structure become softer and spongier.
FILAMENTOUT
RAW MATERIAL IN
HEATING BAND(PID
CONTROLLED)
EXTRUDER MOTOR
CONTROL ELECTRO-
NICS
0.0
20.0
40.0
60.0
80.0
100.0
120.0
PCL PCL-TCP 80:20 PCL-TCP 70:30
Ap
par
ent
Mo
du
lus
(MPa
)
FLEXURAL TEST
0.0
10.0
20.0
30.0
40.0
50.0
60.0
PCL PCL-TCP 80:20 PCL-TCP 70:30
Ap
par
ent
Co
mp
ress
ive
Mo
du
lus
(MPa
)
COMPRESSION TEST
0
10
20
30
40
50
60
70
80
90
100
PCL PCL-TCP 80:20 PCL-TCP 70:30
Wat
er U
pta
ke (
By
% M
ass)
WATER UPTAKE PERCENTAGE
FILAMENT PRODUCTION• Filament Extruder nozzle at 110˚C, with an extrusion rate of ~1mm/s• Pushes material with a chrome-plated auger bit• Two nozzle sizes (1.76mm for pure PCL, 2.0mm for TCP sample) due to
rheological effects of melted PCL (shear thickening)
0
5
10
15
20
25
30
PCL PCL-TCP80:20
PCL-TCP70:30
PCL-TCP60:40
Perc
enta
ge D
iam
eter
Incr
ease
RHEOLOGICAL EFFECTS(SHEAR THICKENING)
1. Su B. et al., Journal of the European Ceramic Society, 28(11), 2008: 2109-2115.
2. Bose S. et al., Materials Today, 16(12), 2013: 496-504.3. Hollister S.J., Nat Mater, 4(7), 2005: 518-524.4. Bose S. et al., Trends in Biotechnology, 30(10), 2012:546–554.
• 3 point bending test• 100 N load cell• 3.5mm x 4.4mm x
70mm samples• 56mm span
http
://w
ww.
scul
pteo
.com
YANG LAB: PRESENTATION OF RESEARCH
ME101: TOWER
OUR CHALLENGE: BUILD THE TALLEST TOWER USING: -12 SQ. FT OF FOAM CORE -RUBBER BANDS, PENCILS, GLUE -HAS TO BE INSIDE 13’X13’ CONSTRUCTION ZONE -NO PIECE OF THE TOWER CAN BE > 1.5 FT3
OUR POV: -CREATE A SELF-DEPLOYING TOWER. -NO STACKING NECESSARY. -AS TALL AS POSSIBLE (16.5’ !)
ME101: DOGGIE FETCH
OUR CHALLENGE: CREATE TWO MACHINES THAT: - MOVE 1M AWAY FROM ONE ANOTHER - PAUSE AT LEAST 3 SECONDS - THROW AND CATCH PING PONG BALL - THE RECEIVER CELEBRATES - THE RECEIVER ROLLS BACK
ALL WITH THE PULL OF A STRING.
ME101: DOGGIE FETCH SELECTED LOGBOOK PAGES
ME101: DOGGIE FETCH SELECTED LOGBOOK PAGES
ME101:
DESIGNING FINANCE
OUR CHALLENGE: USE d.THINK TO IDENTIFY, EMPATHIZE, DEFINE, IDEATE, AND PROTOTYPE THE FUTURE OF PERSONAL FINANCE.
IT’S OVERWHELMING. We have so many different
ways of paying for things—from
credit/debit cards, to Venmo, to
PayPal, to cold hard cash.
Keeping track of where our
money goes gets tough quickly.
…because wallets are so 2010. Schwal (v) : to pay somebody, using Schwallet.
March 11, 2014
CARD COVERFLOW When prompted by a compatible Schwallet receiver, pick
which card you’d like to use, and check up on your
balance (and potential warnings associated), all before
you press pay.
Sometimes options are nice. But when you’re stuffing your pockets with cash and cards, how do you keep track of your
finances?
HOW MIGHT WE consolidate our transaction
processes into one, easy to
use interface?
I HATE MY BANK ACCOUNT. Our collective emotional
connection / relationship with
our bank accounts are a source
of stress and anxiety.
HOW MIGHT WE make it fun to be on top of
our finances?
CASH? NO. If wallets are so 2010, cash
is like, so 1776.
HOW MIGHT WE create a platform where
interacting with money is as
satisfying as slapping a wad
of Benjamins on a table?
Schwallet (n) :
SchwaLtastic features
PICK YOUR WEAPON. YOU HAVE THE FREEDOM.
Saba Fazeli
May the balance be with you Sick of having to log into your bank’s terribly laid
out account management system? Every time you
even try to look at your payment methods, you
have to see how much money you have left, and
how much of your budget you’ve burned through.
If you don’t have much, we’ll tell you. Bye-bye
overdraft fees.
A Truly worldwide connection Bluetooth-enabled communication between your
phone, Schwallet enabled magnetic card readers,
and other Schwallet users. Make it rain, everywhere.
I.D. Linking Once you’ve decided how you’re going to pay for
your goods, show the cashier a picture of your face.
If it’s you, you should be good to go. If not, there may
be bigger issues at hand.
$452.36!
DRIVER INDEPENDENCE FOR OLDER ADULTS A JOINT PROJECT BETWEEN DESIGN FOR AMERICA AND CHRYSLER
WORKED IN A TEAM TO IDENTIFY, DEFINE, IDEATE, PROTOTYPE, AND PRESENT A CONCEPT TO CHRYSLER HEADQUARTERS IN DECEMBER 2013. CONCEPT VIDEO ON YOUTUBE.
INDEPENDENT STUDY: HAND CRAFTING A BICYCLE FRAME
d.school: SUMMER MAKER WHAT: PLANNED AND EXECUTED A THREE DAY DESIGN THINKING BOOTCAMP FOR 100+ TEACHERS FROM AROUND THE WORLD. HERE ARE THE MATERIALS I HELPED CREATE.
TO THE LEFT: A DESIGN CHALLENGE FABRICATION GUIDE, AIMED FOR TEACHERS.
BELOW : THE TWO CHALLENGES WE RAN THROUGH DURING THE TEACHERS’ STAY. THESE ARE THE COVERS FOR EACH BOOKLET, WHICH HAD SPACE FOR THE TEACHERS TO RECORD THEIR PROCESS.