2.72 Group 5
Design Review 1
2/23/08Eric Correll, Josh Gafford, Andrew Marecki, Stephen Powelson, Johannes Schneider, Sam Weiss
2.72 Group 5 - Spring 2009 2
Objective
Project timeline and updates Introduce shaft design Calculations, diagrams, and results Further discussion
GANTT Chart
…wait one second…
Individual Updates
Steve – Solid Model Sam – MathCAD Eric – Machining Andy – Documentation Josh – FEA Johannes – Measurement
Measurement
Shaft Design
CalculationsSe ka kb kc kd ke kf Sut 206.87MPa
0 2 4 61 10
3
0
1 103
2 103
YX
Position (in)
She
ar (
N)
0 2 4 620
0
20
40
60
80
100
YXTotal
Position (in)
Mom
ent (
N*m
)
max M( ) 88.9N m
Typical cutting force: 500N
Part yield at ~1000N
(3/8” Al, cut 1.25” from chuck)
Tensioning force from pulley,
2 to 3kN max
0 2 4 60
0.5
1
1.5
Shaft Diameter
Safety Factor
0 2 4 60
1
2
3
4
5
Safety FactorShaft Diameter (in)Stress (Rel. to max)Safety=1Safety=1.5
Minimum safety factor given stress concentrations is n=1.3
Deflections and Angles
0 2 4 6
2 103
2 103
4 103
6 103
Y deflection (in)X deflection (in)
0 2 4 6
0.15
0.1
0.05
0.05
0.1
Y angleX angle
Deflections and Angles (cont.)
0 2 4 6
2 103
2 103
4 103
6 103
Y deflection (in)X deflection (in)
0 2 4 6
0.15
0.1
0.05
0.05
0.1
Y angleX angle
FEA confirms MathCAD analysis. Compare FEA of solid model (above) with MathCAD calculated deflection (in red, right).
Questions
Is the bearing order only for the spindle bearings?
Chuck fitting and size? Motor specs (torque-speed curve)? Motor mounting fixture? Pulley tensioning?