Abstract: Micro-size effects are the characteristic phenomena in the processes of metal micro-forming, and therefore are the choke point of the farther researching on micro-forming technics and theoretics. In term of the analytical results on the numerous experiments, the micro-size effects are classified as material attributive micro-size effects and technical condition micro-size effects. The correlation and the dynamic property of the micro-size effects are analyzed on the base of the mi-cro-forming system and the causes of micro-size effects are anatomized from the viewpoint of constitutive theory; On the basis of similarity science, a new concept, similarity precision is defined as similarity metewand of micro-size effects, and the expressions of similarity precision involved correlation and dynamic property are also given. Above metewand and meth-ods of evaluating are demonstrated by adopting data of litera-ture, The results indicate that the classifying method of mi-cro-size effects is true of engineering practicality and the results from the methods of evaluating are accordant with those in literature. Of course, these systemic methods of evaluating and classifying of micro-size effects can be extended over other microsystems.

Key words: Correlation, Dynamic property, Material attributive micro-size effect, Micro-size effects, Similarity precision, Technical condition micro-size effect