In recent decades micro-manufacturing becomes increasingly important. Complex multi-material and multi-functional products are required in industries such as bio-medicine, transport, consumer electronics etc. These products, however, cannot be made by single process. Combination of various shaping and assembling processes is required. This paper, gives a systematic overview on the topic of process changing. Clear and systematic process classification system and appropriate design and modelling strategy are presented. Special emphasis is put on planning of complex manufacturing chains. This paper shall help process engineers to make their decisions easier.