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Computer-aided process planning (CAPP) is becoming increasingly crucial to today's computer-integrated manufacturing (CIM) and rapid production. To automate the process planning, feature-based operation planning systems have been suggested and studied extensively. In such a system, given a machining feature, the operator requires practical machining operation data for the feature. In this research, a system of reverse engineering is proposed to extract machining features and their associated machining operation data. Furthermore, a machining know-how database containing the extracted data is created for future operation planning. Since successful NC programs contain the machining know-how of skilled workers, the system is aimed at extracting the machining know-how data from the NC programs through reverse engineering. The extraction of the machining features and feature topologies has been addressed previously. The present paper deals with the extraction of machining operation data, including operation se...

To automate machining process planning, the acquisition and representation of machining knowledge or know-how in a reusable way is needed. The machining know-how is implied in NC programs made by experienced workers. In this paper, the methodology and system for extracting machining know-how in milling operations have been developed. With the system, machining features, operations and their associated cutting conditions (depth of cut, feed rate and spindle speed, etc.) and machining method can be extracted by analysing NC programs in conjunction with the tools used and workpiece blank model. The milling know-how is represented as a collection of these extracted data that can be used in future machining operations. To verify the system, actual NC programs for milling have been analysed and the milling know-how has been extracted successfully.

A conventional absolute encoder consists of multiple tracks and therefore has a large size. Based on the theory of shared control, a new kind of absolute encoder called the shared track Gray encoder is proposed. This encoder has only one track, and the code has the characteristics of Gray code. In this paper, first the working principle of the encoder is introduced and the existence condition of the codes for the shared track Gray encoder is derived. Then the search procedure for the codes using self-developed assembler programs is given. Finally, the pattern of the encoder is presented. Since the shared track Gray encoder has only one track and the code is progressive, it is much smaller in size and higher in accuracy than a conventional one. [S0022-0434(00)01503-3]