ESCO-Nestable Crate

Paul Silver Gary Hicks Chad Freitag Anwar Al-Alawi

Design Brief

The project was to design a reusable crate that would be collapsible, stackable, and/or nestable, such that it can be returned to ESCO once the product has been shipped using minimal cargo space.

Four Step Process

Product Design Specification External Search Internal Search Concept Evaluation & Decision

Each step applied to all major components of project

Outgoing, Stacked

Return, Nested

Design Concept

Sizing/Proportion Analysis

Must fit logically/spatially into 20’ cargo container

Packing density of 55-gallon drum Spacing around crates for easy

movement with forklift Crate size/proportions computed 20 crates per 20’ cargo container

Sizing/Proportion Analysis

Material Selection

Durable, lightweight, recyclable Low maintenance Exposure to harsh environment Commonly available Proven performer

Material Selection

High Density Polyethylene (HDPE) Structural foaming agent Opportunity to learn about plastics

Chest & Lid Geometry

GE Plastics - Injection Molding Guidelines

EDS IDEAS - solid modeling

Chest & Lid Geometry

Chest & Lid Geometry

Structural Analysis

EDS IDEAS CHEST Maximum Von Mises-3900 psi Maximum deflection-0.139” LID Maximum Von Mises-3750 psi Maximum deflection-0.323” COMBINED WEIGHT - 176 lb

Structural Analysis

HDPE yield strength - 4800 psi

Chest Safety Factor - 1.23

Lid Safety Factor - 1.28

Structural Analysis

Structural Analysis

Structural Analysis

Manufacturing

Manufacturing

Low Pressure Injection Molding Aluminum tooling vs. steel tooling Aluminum is less expensive and

requires less lead time Influence on design process

Economic Analysis

Crate vs. 55-gallon drum Drums - $9 Crate - $187

Based on 5-year span Drums - $302,400 Crates - $478,720

Economic Analysis

Crates cost more Difficult to place price on long term

environmental savings What are you willing to pay for

environmental preservation? Salvage value - can be used for

less strenuous tasks Storage Material movement

Rapid Prototype

PSU rapid prototype machine Verify nesting ability Verify stacking ability

Further Development

Design optimization Reduce weight Decrease stress concentration

Different loading conditions Impact Crane straps

Quotes for initial production run

Conclusion

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