Compression and cushioning characteristics of moulded pulp packaging

Experiments have been carried out to determine the relationship between the geometry of a moulded pulp packaging and the resulting static and dynamic strength. The influence of the shape of the moulded pulp sample has been examined. The shapes were of rounded and squared geometry, with different draft angles, sample heights, volumetric density in order of the level of hotpressing and surface densities. Static strength was examined by compression test. The experimental results show that cylinders, cones and shapes with large roundings produce better compression strength than squared or rectangular products with small roundings. Dynamic strength was found using drop tests to obtain G curves for first impact of the test samples at different conditions. An equation to determine the maximum G value during the drop was found. The equation shows good correlation to the results achieved for small static loads (the left side of the G curves). C/e curves for the different geometries show that the minimum cushion factor attainable for the tested moulded pulp products is approximately 2.0.