【正文】 Rugged Table saws, sewing machines, machine tools 1525 g39。s. ? [Solution] 1. Since a product typically faces repeated impacts during shipment, you will probably wish to use multipleimpact data. typical drop height for a product of this weight may be estimated from the chart below as 24 inches. Step 3 Calculate Cushion Requirements 3. Obtain the cushioning curves for the cushioning material you wish to use. Locate curves that represent multiple impact data from a drop height of 24 inches. 4. Determining Thickness ? locate our product39。s) on the vertical axis of the figure, and draw an imaginary horizontal line across the chart at this level. This separates the chart into two sections: ? our fragility line and lower, where the packaged item will be able to survive the anticipated shock level, and ? the section above our line where the shock levels are high enough to damage the product Step 3 Calculate Cushion Requirements ? choose a thickness of 2 inches for the thinnest cushion thickness. 5. Determining Static Loading and Bearing Area ? The useable part of the curve is bounded by a static loading of psi at the low end, and psi at the high end. This tells us that, with a 2inch cushion, we can apply a static loading anywhere within this cushioning range and still protect to 50 g39。s 4060 g39。s 115 g39。s natural frequency and is enough to prevent vibrational damage from occurring during shipment. ? For severely vibrationsensitive products, it may be necessary for the package design to actually attenuate the frequencies of concern. Step 6 Consider Vibration Effects Figure Typical vibrational response of a package Step 6 Consider Vibration Effects Figure Vibrational response of a cushioning material Step 6 Consider Vibration Effects ? Material response is often given in diagrams similar to Figure , which represent performance for a given thickness of material. Note that for any frequency, one can estimate whether the package will perform in direct coupling, amplification, or attenuation mode as a function of the static loading applied to the cushion. Step 7 Monitor Performance If it works, question it ? There are many assumptions that went into your design development. ? It is a good practice to monitor the performance of your design in actual use. This will help you to determine if your design is providing more realworld performance than is actually required, or not enough. ? Monitoring of packaging performance on an ongoing basis can also help determine if further economies can be achieved without sacrificing protection.