How To Use Dynamic Cushion Curves
- Each chart of cushion curves has a vertical axis (fragility - G's) and a horizontal axis (static loading - psi).
- Determine the cushioning material and the required drop height.
- Choose the fragility level to which the material must perform.
- Draw a horizontal line across the chart at the fragility level from #3.
- Each chart has five curves representing thicknesses 1 through 5.
- The horizontal line will intersect 1 or more curves on the chart.
- To achieve the desired protection with a minimum amount of cushioning material - select the thinnest material curve. This choice is the cushion thickness used to design the packaging.
- Draw 2 vertical lines at the 2 points where the horizontal fragility line intersects the curve.
- These 2 points represent the effective cushioning range for the material. Any static loading between the 2 points may be used to calculate the bearing area (amount of foam required).
- To determine the bearing area on each side use the following formula: Bearing Area = Product Weight / Static Loading.
- To use the least amount of cushioning material, select the static loading at the intersection point on the right side of the curve.
Cushioning material: Ethatfoam 200LC
Drop Height = 24 inches.
Product Weight = 36 lbs.
Fragility = 40 G's
The horizontal line at 40 G's intersects the 2" and 3" curves.
We will select 2" - and this becomes our cushion thickness.
The effective cushion range is .4 psi to 1.2 psi.
Using the bearing area formula in #10 above: 36 / 1.2 = 30 square inches on each side.
Therefore, the cushioning needed to protect the product will be 2 inches of cushion and 30 square inches of bearing area on each side.