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?