2.72 Design Lab Meeting02/23/09

Group 4

Purpose

To give progress on the project

To give details of work to date, and future plans

To ask questions regarding other parts

Meeting Outline

ScheduleUpdate on Shaft Fatigue AnalysisDesign & Modeling, HTM, FEA

ShaftHousingEnd CapCrossfeed FlexureLead Screw Flexure

Measurement: Spindle ErrorFinancial UpdatesQuestions

Gantt Chart by 04/06

Fabrication

- Spindle Shaft- Spindle Housing- Housing end caps- Cross-feed flexure - Lead-Screw flexure

Error Models

- Spindle Error- Flexure Error- Drive Error

To-Do

CMM for crossfeed flexure, lead screw flexure

Design and manufacture lead screw drive

Motor Mount, drive system (gear vs. belt drive)

Documentation

Process plans with 2D Cad drawing and 3D rendering

- Spindle Shaft- Spindle Housing- Housing end caps- Cross-feed flexure - Lead-Screw flexure

Shaft Fatigue Analysis

Endurance Limit: Se = 188MPa*

Fatigue Strength: Sf = 269 MPa (70,000 cycles)

Expected Life: N = 5 billion cycles

Safety Factor: n = 4.5

(*: see MathCad file for various factors and calculations)

Design & ModelingSpindle: Shaft

Design & ModelingHousing

Design & ModelingEnd Cap

Design & ModelingSpindle Assembly

Design & Modeling INSERT PICTURE

Crossfeed Flexure

FEA: Crossfeed Flexure

Static analysis- Dimension flexure with 30% stress factor of safety

Dynamic analysis- Check first 3 modal frequencies, ensure not too low

Static Analysis

Dynamic Analysis - First Vibration Mode

Dynamic Analysis - Second Vibration Mode

FEA Results

Design & ModelingINSERT PICTURE

Lead Screw Flexure

MORE FEA STUFF FROM EVAN

Measurement

Measured spindle error using Donaldson Ball Reversal Method

Error Measurement Results

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Ranges from -15.1 to -40.1 microns (∆= 25 microns)

Comments: Nut loosened. Double nuts?

Financial: Orders & Budget

Bearing Number:  LM12749                             LM12710$6.77 EachTimken Tapered Roller BearingsShaft diameter 55/64”Outside Diameter 1-25/32”

Part Number:  9712K92 $14.38 per Pack of 12Belleville Disk SpringsGrade 1074 High-Carbon SteelMinimum Inside Diameter:     0.880"Maximum Outside Diameter:  1.750"Thickness:  0.085"

Financial: Orders & BudgetPart Number: 89535K31 $28.33 EachRail Length 6'Diameter 5/8"Multipurpose Stainless Steel 304/304L

Part Number:  6391K247 $0.98 EachBusing Length: 3/4"OD: 3/4"ID: 5/8"SAE 841 Bronze

-Ordered: 12 tapered roller bearings, 1 pack of 12 disc springs, 1 six foot steel rail,3 bushings = $126.89-Needed: 1 six foot steel rail, 15 busings, Between 6-12 shaft nuts (estimated $1Each) = $55

Budget: $200Used: $127Needed: $55Extra: $18