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Novel Material and Mechanical Design for Shipping Pallets
Justin Gallagher, Taylor Hopkins, Craig Leslie, Niko McMurray, Kevin Rebellino Advisor: Dr. Daehn Partner: Alcoa Foundation
Background • Global packaging market – Over $459 billion* • Wooden pallets ▫ Cost $20 each** ▫ Weigh 50 lbs.** ▫ Not environmentally resistant ▫ Non-recyclable ▫ Potential for invasive species
*:"Pallet Trends." Solutions For Wood. FP Innovations. Web. 1 Dec. 2011. <http://www.solutionsforwood.ca/_docs/reports/PalletTrends09.pdf>. **: Pallet Sizes and Dimensions. http://www.palletsunlimited.com/pallets_size.html. ***: "Aluminum pallets." Aluminum pallets. N.p., n.d. Web. 4 Dec. 2011. <http://www.aluminum-pallets.com/>.
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Background • Wooden pallets ▫ Occupy 4% solid waste in
landfills* ▫ Deforest up 100 million
acres of forest each year* ▫ Short life span- generally
single use*
*: Loadek - the First 100% Corrugated Pallet. Web. 01 Dec. 2011. <http://www.loadek.com/index.htm>. **: "Aluminum pallets." Aluminum pallets. N.p., n.d. Web. 4 Dec. 2011. <http://www.aluminum-pallets.com/>.
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Background
• Plastic pallets ▫ Cost $60-100 each* ▫ Weighs between 30-50 lbs.* ▫ Lack rigidity ▫ Low creep resistance at high loads ▫ Recyclable
*: Premier Pallets FAQ. http://www.premier-pallets.com/faqs.asp. **:"Aluminum pallets." Aluminum pallets. N.p., n.d. Web. 4 Dec. 2011. <http://www.aluminum-pallets.com/>.
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Background • Aluminum pallet ▫ Cost at least $200 each* ▫ Weigh ~35 lbs.* ▫ Longer life span ▫ More visual appealing
*: National Wooden Pallet and Container Association. http://www.palletcentral.com/. 2010. **:"Aluminum pallets." Aluminum pallets. N.p., n.d. Web. 4 Dec. 2011. <http://www.aluminum-pallets.com/>.
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Background • Aluminum pallet ▫ Recyclable/ .97 cents per lb.* ▫ Environmentally resistant ▫ Do not carry insects/bacteria
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*: National Wooden Pallet and Container Association. http://www.palletcentral.com/. 2010. **:"Aluminum pallets." Aluminum pallets. N.p., n.d. Web. 4 Dec. 2011. <http://www.aluminum-pallets.com/>.
Motivation of Project
• Design an sustainable shipping pallet to fulfill a market need
• Produce at a lower lifetime cost than currently available options
• Use manufacturing processes that can be highly automated, and therefore, cost will be close to that of raw material at high volume.
Design Criteria
• Aluminum pallet ▫ Dimensions*: 48”x42”x6” ▫ Minimize weight/increase strength ▫ Decrease cost (under $100) ▫ Possess a load bearing capacity of 2000 lbs
(Dynamic) & 6000 lbs (Static)** ▫ May be transported by standard forklifts* ▫ 100% recyclable
*: ISO 6780, Flat pallets for intercontinental materials handling-Principal dimensions and tolerances **: ISO 8611-2, Pallets for materials handling-Flat pallets-Part 2: Performance requirements and selection of tests
Technical Approach
• Widely available material – Al alloy 6061-T6 • Each group member contribute designs • Use various manufacturing methods – maximize
automation • Determine at least two viable designs • CAD – meet weight and design standards • FEM – meet ISO standards • Prototype – viability of manufacturing
Industrial Origami
• Rapid, simple manufacturing process • Perforations made along fold lines • Shapes folded in sequence
*: Industrial Origami. Design and Technology Overview. Middleburg Heights, Ohio. 2012. http://www.industrialorigami.com/technology/science.cfm.
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Joining Methods-Welding • Welding Aluminum ▫ Heat input ages
material rapidly ▫ Leads to
overcoarsening of precipitates, massive grains* ▫ IWSL process uses
water cooled electrode Focuses current at
weld site
*Mathers, Gene. The Welding of aluminum and its Alloys. Woodhead Publishing. 2002. London.
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Joining Methods-Adhesive
• High strength adhesives for structural applications ▫ Example: Lotus Elise/
Exige chassis ▫ Important properties Peel and shear strength,
corrosion resistance
*Lotus Exige, body and bare chassis. http://www.europeancarweb.com/firstlook/0603_ec_2006_lotus_exige/photo_04.html
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Industrial Origami Stress Analysis • Basic finite element
analysis • High stress regions
where top is bonded to middle sections
Industrial Origami Fabrication
• Shapes formed with hydraulic shear, manual bend press
• Pieces were bonded using Loctite E-120HP • Substituted U-channels for expansion formed
channels
U-Channel Design
• 6061-T6, 48”x42”x5”, 21.9 lbs • Requires only two distinct pieces • 0.065” channel thickness • 0.010” tube thickness
U-Channel FEM
• Modeled in Solid Works
• 0.14 cm deflection at max. loading
• 107 MPa VonMises stress at max. loading
• 6061-T6 yields at 276 Mpa at room temp.*
* http://www.matweb.com/search/DataSheet.aspx?MatGUID=1b8c06d0ca7c456694c7777d9e10be5b&ckck=1
U-Channel Fabrication
• Water Jet holes in sheets
• Bend cut out patterns • Use electromagnetic
expansive forming
Interference Fit Extrusions Background
• This design relies on two types of pieces • Very similar to U-Channel design produced • Number of required parts reduced for decreased
costs
Interference Fit Extrusions Design • 6061-T6, 48”x42”x5”,
23.4 lbs • Holes cut in T-beams
to reduce weight • Varied wall thickness
to reduce weight
Interference Fit Extrusions FEM • Stress concentrations
are a limiting factor • VonMises stress of
196 MPa at max. loading
• Max. displacement 0.15 cm in dynamic loading
Design Comparison
• U-channel is the lightest and cheapest design • The origami design allows 4-way entry • T-Beam has deflects more than U-channel ▫ Equivalent FEM was not run for both, however
loads are roughly comparable
Design Weight Material Cost Entry Deflection
Industrial Origami 28.8 lbs $57.6 4-Way 0.061”
(6000lb Static Load)
T-Beam 23.4 lbs $46.8 2-Way 0.055” (2000lb Dynamic Load)
U-Channel 21.9 lbs $43.8 2-Way 0.057” (2000lb Dynamic Load)
Testing
• ISO Standard 8611-2 ▫ Static and Dynamic Load ▫ Deflection
• A large test frame must be found or designed to allow the maximum load to be determined both statically and dynamically ▫ Nominal load is defined as the load at which the
maximum deflection is less than 20mm, or 0.787”
Results
• 3 viable options ▫ All weigh < 30lb ▫ Estimated cost < $75
• 3 different manufacturing methods ▫ All manufacturing methods commercially viable
• FEM analysis – Passed Requirements ▫ 2000lb Dynamic and 6000lb Static Loads
Design Conclusions
• U-Channel is lightest at 21.9 lbs • All components are easily manufactured ▫ Can be available in larger quantities
• Simple Construction ▫ Expansive forming must be optimized for large
scale production ▫ Spot welding is also an option
Future Recommendations
• Testing ▫ Based on ISO standards
• Develop a process for fabrication ▫ Automatable, as much so as possible
• Address other design aspects ▫ Aesthetics, Stackability, Design optimization
Acknowledgements • Advisor: ▫ Dr. Glenn Daehn
• Department of Mechanical Engineering Advisors: ▫ Dr. Tony Luscher and Dr. Leo Rusli
• Industrial Partners ▫ Bill Shepard from Die Matic, ▫ Dr. Dr. Anthony Ananthanarayanana from Innovative
Welding Solutions Ltd. • The Aluminum Company of America (ALCOA) • Dr. Daehn’s Lab: ▫ Geoffrey Tabor and Ryan Brune
• Dept. of Mechanical Engineering machine shop: ▫ Chad Bivens and Matt Little