Micro-milling is a precision manufacturing process with broad applications across the biomedical,electronics,aerospace,and aeronautical industries owing to its versatility,capability,economy,and efficiency in a wide range of materials.In particular,the micro-milling process is highly suitable for very precise and accurate machining of mold prototypes with high aspect ratios in the micro-domain,as well as for rapid micro-texturing and micro-patterning,which will have great importance in the near future in bio-implant manufacturing.This is particularly true for machining of typical difficult-to-machine materials commonly found in both the mold and orthopedic implant industries.However,inherent physical process constraints of machining arise as macro-milling is scaled down to the microdomain.This leads to some physical phenomena during micro-milling such as chip formation,size effect,and process instabilities.These dynamic physical process phenomena are introduced and discussed in detail.It is important to remember that these phenomena have multi-factor effects during micro-milling,which must be taken into consideration to maximize the performance of the process.The most recent research on the micro-milling process inputs is discussed in detail from a process output perspective to determine how the process as a whole can be improved.Additionally,newly developed processes that combine conventional micro-milling with other technolo-gies,which have great prospects in reducing the issues related to the physical process phenomena,are also intro-duced.Finally,the major applications of this versatile precision machining process are discussed with important insights into how the application range may be further broadened.