An increase in competition in the automotive industry makes Thai auto part manufacturers to regulary modify the part designs and their production processes. In order to increase the competitiveness of automotive part making, it is necessary for the part manufacturer to develop knowledge in designing and producing parts by themselves.

The most popular material used in the manufacture of automotive load-bearing parts is steel. Many efforts have been used to develop various features continuously to make the steel thinner or lighter while maintaining comparable strength properties to the original. This aspect always contributes to the energy savings.

However, with the existence of alternative materials e.g. engineering or advanced plastics, many automotive parts could be made even more lighter and at lower cost than steel. To make automotive parts from plastics, modification in the part design and material selection based on considerations in the functions, strength, service temperature range and working conditions of the part must be considered.

In addition to this, manufacturing process needs to be consistent with the part design. Generally, forming of plastic parts comprises fewer steps than steel forming for example injection molding of plastic is a one step process with which the manufacturing cost is greatly reduced compared to manufacturing of steel parts.

Modern tools such as computer-aided engineering and process simulation are increasingly playing a role in nowadays material replacement works. In summary, knowledge of the design, material and manufacturing process are required factors in developing of a metal replacement plastic part having satisfied overall quality and cost.