Recently, there has been an increasing interest in lightweighting design and production technologies in automotive industry owing to energy efficient vehicle requirements. Microcellular physicial foaming using supercritical fluid inert gases, known as Mucell, is an important approach to lightweighting technology for a wide range of scientific and industrial applications. Synergistic effect of design and foam structures enable ultimate weight reduction ratios. Therefore understanding of relationship between design and foaming processes is important for optimization lightweight design and production of the plastic parts. Studies over the past two decades have provided significant information on microcellular foaming through batch process. In this study, the relationship between design, process parameters and foam morphology was investigated through continuous process on industrial scale. The influence of key microcellular foaming parameters such as supercritical fluid gas amount, temperature of polymer melt, injection speed on variable design structures used in automotive applications such as rib, boss was evaluated. The weight reduction ratio and dimensional accuracy of microcellular molded samples were determined. The flexural and impact behavior of the microcellular molded samples were measured and microscopic investigation of microcellular foams was analyzed.