Papers by Author: Y.J. Cai

Abstract: As one of major methods to meet information integration of numerical control machines in workshop, DNC (Direct Numerical Control or Distributed Numerical Control) oriented networked manufacturing (Web-DNC system) differs dramatically from conventional ones by having: (1) concurrently supporting networked manufacturing; (2) sharing the numerical control machines via network; (3) optimizing the configuration and reorganization of numerical control resources. This paper deals with the key technologies of Web-DNC system, including: the implementing architecture model with four layers (user layer, service layer, agent layer and facility layer) and the topology architecture. The BL2000 SCM is selected as a COM server to meet the required capabilities of DNC controller. Compared with the communication architecture with fieldbus, a simpler function model of DNC communication technology based on Ethernet technology is presented. A Web-DNC system prototype is developed and proved to be effective in information integration of numerical control machines in injecton workshop.

Abstract: Sculptured surface machining is a critical process commonly used in die and mold industries. Since there is a lack of scientific tools in practical process planning stages, feedrates of CNC machining are selected based on previous experiences. In the selection of feedrate, the feedrate is set an individual conservative constant value all along the die cavity roughing processes in order to avoid undesirable results such as chipping, cutter breakage or over-cut due to excessive cutter deflection. Usually, volumetric models or vector force models used for optimizaton of feedrates must be created to get the variable feedrates along the tool path. Considering the die cavity roughing being a 2.5D cutting, a novel cutting force surface model is created based on orthogonal cutting tests to adjust the feedrates. The model is tested by a typical die-cavity roughing, thinning down machining time and balanced cutting-load can be attained. The presented feedrate scheduling characterized by balancing the cutting-loads in die-cavity roughing will be more significative in high speed machining.