PC-NC system, which is package control of the machine tool using PC (Personal Computer), is more improved than the existing machine in network, storage, and operating system. Because it is possible to have the software of CAD/CAM within the system, the PC-NC system has advantages to execute the 3-D simulation of machining and to execute the machining. The DPROM used in this study can model general features, simulate machining, create the tool-path and generate G-code. The developed system can conduct manufacturing and inspection on one system by linking the OMM-module with the AFFA (Advanced Fast File Access) of DPROM. Fig. 1 shows the mutually connective structure between DPROM and OMM module. The data of CAD/CAM are interfaced to OMM-module for owning geometric information. In Fig.2, the section of user interface of OMM-module is shown. It is possible to select function of the machining and inspection of each feature. In Fig.3, the structure of OMM module is shown. The OMM module can execute automatic measuring system considering the geometric feature of CAD/CAM. It is possible to generate G-code for touch-probe moving and to perform the simulated inspection. The developed program is applicable for the existing system and the other functions except the function of joining the geometric feature information are made independently.

Fig. 1 The structure of In/Out data in DPROM & OMM module

Fig. 2 The user interface OMM module in DPROM

Fig. 3 The structure of OMM module

3. The OMM module

The existing OMM operating methods are of two types. One is programming probe path at machine tool directly, the other is the type where a user distribute measuring points in a feature using CAD data manually. But these methods can not measure machining    features

automatically. In this study, there are machining features decomposed into 3D surface and we call it inspection feature. The inspection variables were determined according to geometric characteristics of inspection features. On the occasion of the inspection of the same feature(Fig.5), the OMM-module recognizes the geometric information of CAD/CAM as in Fig.4, and can inspect the workpiece using three modes, such as Manual mode, General mode and Automatic mode after changing the compound feature of workpiece into the inspection feature. The Manual Mode requires the inputs regarding the information of position to be inspected. The input variables are the information of inspecting position (P2) and the position of recession of probe (P1) in the Manual mode.(Fig.5(a)) The General Mode is suitable for the inspection of an analytic features(feature based surface) and the input variables are the number of sections to be inspected(NP) and the number of inspection points for each section.[6][7][8](Fig.5(b)) The Automatic Mode achieves the inspection by classifying the feature of CAD/CAM into the proposed inspection feature. (Fig.5(c)) The input variables are the repeatability of machine tool, the leading resolution value for OMM and the    area    of    inspection    feature.    In    addition,  the

information and safety distance of probe can be inputted. Fig. 6 shows the algorithm that determines the inspection variables (the number of measuring points, their location, probe path) for automatic mode. The number of measuring points is determined by Fuzzy logic. The location of measuring points is determined by Hammersley’s algorithm and the probe path is decided by 2~3 guide points and TSP (Traveling Salesperson Problem) algorithm. Because the inspection variables of the Manual and General modes are inputted by an operator, their inspection is performed without applying the algorithms described previously.

3.1 Determination the number of measuring points using Fuzzy-algorithm