daimler chrysler car transport upgrade team #3 john barr aladrian crowder hilary goldman matt reber
Post on 20-Dec-2015
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Background Information Daimler-Chrysler Newark
Assembly Plant Assembly Process: 3
phases of production Paint Shop: workings and
history Transport System:
difference from plant norm
Phosphate and E-coat Process
Accumulation Lines: unique conveyor system
Accumulation Lines Skids go into
holding pattern when production is down
5 accumulation lines, each 200 feet long
Motor driven chain with high rollers
Problem Definition Destructive nature of
friction and wear from accumulation chains has caused severe damage to skids used in paint shop. Worn skids must be replaced and system must be modified to decrease effects of friction and wear.
Other Effects to System Cast iron rollers
showing same wear pattern as skids.
Worn skids fall off rollers – leads to down time and lost money
Life of System Components
A new fleet of approximately 80 skids are going to replace the current model, after 6 years of use.
Drive motors for accumulation chains are being over-worked.
All 826 cast iron rollers and bearings are being replaced.
Mission Statement
To develop a concept and working design that will significantly decrease the wear experienced by the skids.
Wear Model Primary material property affecting
wear rate is hardness. Wear rate is inversely related to
material hardness by Archard’s Equation:
V=volume, K=wear rate, F=force, L=sliding distance, H=hardness
H
FLKV
Concept Development Initial Brainstorming
Increase wear resistance Eliminate wear
Increase Wear Resistance Alter hardness of current material Add sacrificial wear material
Eliminate wear Break contact between skid and chain
Increase Wear Resistance Alter Hardness of Current Material
Flame or Induction Hardening Suitable for 1045 steel Other properties of material do not change Wear-resistant coating
Bottom of skid directly hardened
Increase Wear Resistance Addition of Sacrificial Wear Material
Plastics Good wear characteristics Easily machined
Metals Attach to skids quickly Used in similar applications in industry
Wear pad
Skid
Eliminate Wear
Break Contact Between Skid and Chain Mechanically lift skid off accumulation
chain Reduces power drawn by motor to
drive chain Change to system is localized
Concept Comparison Wear pads
Plastic Pad Fails due to PV limit Cost far greater than other concepts
Metal Pad Industrial norm Inverse effect on other components of system
Hardening Effects only a minimal depth Similar effects of metal wear pad
Lifter One time application requiring periodic maintenance More complicated solution
Support for Skid Lifter
Eliminates wear on skids Increases life of accumulation
chain Saves energy Reduces drive motor work-load Has no effect on other system
components
Geometry Design of lifter
limited by space Must remain
contained in existing accumulation line area
Goal – minimize volume of lifter
Pneumatic Power Used extensively in paint shop Clean Low maintenance and reliable
Last for 1,000 miles of rod travel Seals need replaced once every two years Valves good for 1,000,000 cycles
Structural(mechanical?) Design Simple machines implemented to
provide lift Inclined plane and wheel Greater distance needed, but less energy
Down PositionUp Position
Space
To keep the accumulation area structurally sound, and the design of the lifter small, it was decided to be contained within area shown.
Skid Lifter Design Pneumatic cylinder will provide force Simple machines implemented to
provide lift Inclined plane and wheel
TestingFrequency of Clearance Height
0
2
4
6
8
10
12
14
16
0.931 0.9519 0.9728 0.9937 1.0146 More
Clearance Height (in)
Scab Plate Strength Test
0
1000
2000
3000
4000
5000
6000
7000
0 5 10 15 20 25
Time (s)
Te
ns
ile
Lo
ad
(L
bf)
Wear Rate Vs Hardness
3. 96E+00
1. 88E+00
2. 38E+00
1. 34E+00
0
0. 5
1
1. 5
2
2. 5
3
3. 5
4
4. 5
180 380 300 533
Current Condtions Flame Hardening I nduction Hardening Sure Alloy Wear Bars
Har n dess C on dit ion
Handoff Plan
Complete design specifications Individual component design Sub-assembly design Assembly instructions
Controls and Safety Logic Company procedure
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