Group 2 – Progress Report

2/23/09

Purpose (Justin)

• Talk about progress the past week• Fabrication of shaft• Shaft exercise• Lessons learned• Getting ahead of schedule

Gantt Chart (Justin)

• (Switch to Excel)

Stiffness Calculation (Corey)

I d4

64

I area moment of inertia of a circle (m4 )

d diameter (m)

K 3EI

L3

K lateral bending stiffness (N/m)

E Young' s Modulus (Pa)

I Area Moment of Inertia

LLength

Keq 1

K1

1

K2

1

K3

1

K4

1

Keq equilibrim stiffness for springs in parallel

K1-4 stiffness of individual sections

Spindle Shaft Dimensions (Corey)

Stiffness Calculation (Corey)

Length (in) Length (m) Diameter (in) Diameter (m)Area Moment

of InertiaK's

1 0.0254 0.5 0.0127 1.27698E-09 4.68E+07

4 0.1016 1.05 0.02667 2.48349E-08 1.42E+07

0.87 0.022098 0.89 0.022606 1.28193E-08 7.13E+08

0.63 0.016002 0.591 0.0150114 2.49261E-09 3.65E+08

           

YoungsModulus (Pa)

  Keq (N/m)

 

Keq(N/mE-6)  

2.00E+11   10426059.6   10.4260596  

Keq=10.426 N/μm

Pre-process Plan (Yi Fei)

• Face-off right most face• Drill live center • Rough cut section A, B, C, and then D• Finish cut section A, B, C, and then D• Cut part to length, take part out

D C B A

Process Plan (Yi Fei)

• Face-off right most face• Drill live center• Turn down whole length to 1.07” diameter• Rough cut and finish cut section C, B, and then

A• Take part out, cut to length, turn part around• Rough cut and finish cut section D

D C B A

Manufacturing (Mark)

• Details

Manufacturing (Mark)

Manufacturing (Mark)

Test Cut Results (Corey)Cantilevered Cuts Diameter (mm)

Mean (mm)1 27.732 27.88

27.913 27.714 27.74    5 27.76    6 28.03

Std Dev7 28.068 28.06

0.169 28.1410 27.99    

       Free End Cuts Diameter (mm)

Mean (mm)1 27.732 27.56

27.6853 27.744 27.71

Std Dev      

0.08Exposed Length (mm) 138.11

•The measured diameters were greater than the target diameter

•The largest diameters were measured from the cantilevered cuts

•~.003 error in touching off tool

•Free end cuts were performed last

Initial Diamter (mm) 28.575Target Diameter (mm) 27.305

Fabricated Shaft (Corey)

(Non) Systematic Errors (John)

CTE=12.2 µm/m-°C

∆L~1 µm

From Manufacturing Engineering and Technology - Kilpakjian

Nonsystematic Errors - Thermal

Non-Systematic Errors: Vibration

• Rotating machinery may excite natural frequencies of lathe, tool, or shaft.

→ Be sure work-piece is centered→ Hold shaft with both chuck and live-center→ Hold shaft as close to cutting zone as possible

Systematic Errors: Tool slip or work-piece slip

• Cutting forces may cause the tool or work-piece to shift because both are held with friction forces only.

• Cause a shift in mean results

→Use moderate feed-rates and depths of cut (accuracy more important than time for this operation)

http://www.sabanciuniv.edu/mdbf/mechatronics/eng/Arastirmalar/Projeler/images/clip_image008.jpg

Cutting forces on order of 250N-1000N

Systematic Errors: Tool Wear

• Any tool wear will result in oversized dimensions• Not enough cutting done to be a large factor of error

→Check tool-zeroing often

Taylor-Tool Life Expectancy Eqation: V_c*T^n = C

Concerns

• Will the current shaft work?• Making sure the second shaft gets

manufactured ‘properly’