Shipping Testing

Transportation or Distribution Testing Overview

  • Focus on testing methods for the distribution of packages.

  • Types of tests include environmental, quality, and specifically transportation or distribution tests (also known as shipping and abuse tests).

Types of Testing

1. Actual Testing

  • Involves real-life conditions for packages.

    • Methods:

    • Loading packages into trucks (18-wheelers) and driving distances between specified locations (e.g., from X to Y).

    • Transporting packages by sea on ocean liners from one port to another.

    • Air transport, loading packages onto airplanes flying between points.

2. Simulated Testing

  • Replicates real-life transport conditions without physical transport.

    • Methods:

    • Loading products in secondary, tertiary, or quaternary packaging units.

    • Using various testing equipment:

      • Vibration tables:

      • Mimics the shaking experienced during transport over different modes (truck, rail, air, sea).

      • Drop tables:

      • Simulates impacts from drops during handling.

      • Compression tables:

      • Tests how packages endure compressive forces.

      • Tests for climatic conditions (high and low temperatures and humidity).

Advantages of Simulated Testing

  • Provides uniformity in testing procedures.

  • Significantly shorter testing time.

    • Example: Simulated tests could replicate the effects of a three-day truck trip within eight hours.

  • Ensures consistent test conditions (e.g., humidity levels affecting package performance).

Drop Testing

  • Graphical representation: Y-axis shows percentage of packages, X-axis shows drop height in inches.

  • Key Findings:

    • 90-100% of next-day air parcels are dropped from heights of 30 inches or more.

    • Relevant to average waist height when carrying packages.

    • Lighter packages tend to be dropped from greater heights, corresponding to handling behavior by delivery personnel.

Shock Testing

  • Analyzes how packages respond to changes in speed and acceleration (impact).

    • Average impact speed: 5 miles per hour.

    • Cushioning in packages can mitigate shock applied during handling and transport.

    • Key Concepts:

    • G-force: Peak acceleration; depicted on the Y-axis against static loading pressure on the X-axis.

    • Fragility factor classes are defined by the g factors associated with items:

      • Extremely fragile: 15-30 g's (e.g., precision instruments).

      • Less fragile items: can withstand up to 150 g's (e.g., mobile phones).

Impact of Cushioning

  • Cushion design aids in distributing shock over time.

  • Visual Graphs:

    • Black solid line depicts immediate acceleration impulse; dotted line shows how cushioning spreads that impact over a longer duration.

Vibration Testing

  • Sources of vibrations encountered include:

    • Structural vibrations from the truck bed.

    • Vibrations from wheels against pavements.

    • Suspension vibrations during transport.

  • Testing ensures how much vibration packages can endure to prevent failures from dynamic environments.

  • Vibrational frequency range: 2 to 50 Hz.

Dynamic vs. Static Compression

  • Bottom boxes in stacks experience greater forces than just the weight above due to vibration and dynamic acceleration experiences.

  • Stacking dynamics impact the strength of boxes — significant compression forces might exist if items on top ‘jump’ during vibration.

Compression Testing

  • Over time, compressive strength of boxes deteriorates.

    • Empirical data shows diminished strength over minutes, hours, and days of stacking.

  • Factors Affecting Compression Strength:

    • Overhang can reduce stacking strength by up to 46%.

    • Design and placement of products within boxes affect the structural integrity and strength.

    • Bulging sides reduce strength further and can lead to failures when under load.

Multi-Component Systems

  • Best strength comes from designs that effectively utilize multi-component systems (e.g., partitions within boxes).

    • Failures in multi-component systems can lead to dramatic shifts in package integrity, impacting all items involved.

Packaging Design Considerations

  • Design packages accounting for additional factors such as:

    • Stacking factors: Combination of static weight and dynamic forces.

    • Specific examples outline how to calculate required package strength:

    • If a package is rated for 50 pounds, and four are stacked above, the vertical stacking factor multiplied by the weight determines the necessary strength for the shipping container to maintain structural integrity throughout transport.

    • Example calculation based on specific scenarios:

      • Bottom box has 200 pounds stacked; multiplied by established stacking factors (5.5 for specific conditions) results in a design loading of 1,100 pounds for the shipping container.

Conclusion

  • The overview of shipping and abuse testing emphasizes the importance of both simulated and actual testing methods, considerations of package design, and the overarching need for consistency and safety in logistics practice. This ensures that products maintain integrity throughout transport and distribution processes.