Direct extrusion is the mostly adopted production method in China. It produces aluminum profiles with better surface, with less equipment involved. Therefore, the investment needed is less than indirect extrusion. Basically, over 90% of China's manufacturers use direct extruders.
Direct extrusion also requires less time to shift moulds (dies) and wider choice of aluminum billets for production. In this term, the production cost is lower than indirect extrusion.
However, direct extrusion needs more time for the extrusion process and higher temperature of the billets, so as to avoid distortion of and to obtain even structure of the products.
Indirect extrusion is normally used to produce seamless aluminum tubes and other machinery parts because its product structure is very even and the chance of distortion is much less than direct extrusion.