PARAMETRIC STUDY OF THE SHOCK CHARACTERISTICS OF EXPANDABLE POLYSTYRENE FOAM PROTECTIVE PACKAGING

The design of expandable polystyrene foam buffers, used as protective packaging for a range of goods, is by and large steeped in heuristics because the design procedures have not been formalized. This paper dis cusses the application of Taguchi's Method of Parameter Design to the determination of the key design parameters of expandable polystyrene f oam end cap buffers. An L-18 orthogonal array was adopted for the plan ned experiments. The eight design parameters considered critical in th e design of the cushioning buffers were product centroid-to-buffer cen troid distance, cushioning area, buffer thickness, wall thickness, mat erial density, rib configuration, rib width, and rib spacing; of these , only buffer thickness, wall thickness and buffer density were found to be significant at a 99% confidence interval. The height of the ribs , being the difference between the buffer and wall thicknesses, is the single most important factor. The buffer cushioning area was found to be not as important as its distribution over the entire load-bearing area and the buffer configuration. The buffers were designed in Unigra phics II, and the post-processing of the NC part program for machining on the Hamai vertical machining center. The impact shock testing of t he end cap buffers was conducted on the Lansmont Model 65/81 Shock Tes t System.