Abstract: The similarity algorithm of injection mold case based on the nearest-neighbor method is studied, and the progress of mold designing and processing means caused by the technical development level in different historical periods is fully considered, then the method of filtering mechanism is proposed to reduce the complexity of matching time caused by enormous case base. Firstly, a certain searching range is limited, and similarity computation matching is carried out only for the cases in this range, thereby maximally improve the computation and matching efficiency of the system. A concise method of adjustment of feature weight is given, so as to correct the inaccuracy produced by the traditional nearest-neighbor method. According to the mold cases retrieved, adjustments are carried out in two aspects, i.e. parts information and assembly structure. The one is offline parts edit based on the standard parts library, and the other is structural adjustment by taking “match relation register” as middleware. Finally, a new method of obtaining and reusing case data during design is proposed, i.e. the design process is written and recorded online and reused whenever needed, which opens a new way for automatic mold design based on cases.

Key words: Based on case-based reasoning, Case adjustment, Case filtering, Design process reuse, Injection mold, Nearest-neighbor method