Yung-Chou Kao

Multi-criteria decision making method for selection of machine tool

The objective of this paper is to show how to determine the valuable criteria for selecting machine tools from the vast amount of specifications of CNC machine tools along with consulting the experts with abundant mold manufacturing experiences is. This research also demonstrate the multi-criteria decision making (MCDM) method towards efficient selections of CNC machine tools that would satisfy the needs of an organization. The research results can serve as a decision-making reference for manufacturing shops to select new machine tools.

An agent-based distributed smart machine tool service system

This research utilized software agent based technology in expanding remote machine tool service system by constructing related remote service ontologies to facilitate its smart and distributive characteristics. These service agents could be used for remote smart machine tool services underlying Internet through the communication protocols supported by both KQML (Knowledge Query Manipulation Language) and FIPA ACL (Agent Communication Language, Foundation for Intelligent Physical Agent) performatives. The mobile agent service for the developed system has also been successfully implemented by transmitting the mobile agent in a file to the serviced side through the Internet.

Development of a Web-Based Virtual Five-Axis Milling Toolpath Simulation System

Virtual machine tool has been used in the toolpath simulation of a real machine tool with very promising achievement in teaching assistance. However, a five-axis milling machine is generally very expensive in comparison with traditional three-axis milling machine in its configuration. This is mostly resulted from the addition of two more rotational axes in five-axis machine. This paper focuses on the development of a Web-based five-axis milling machining toolpath simulation system so as to facilitate the comprehensive understanding of students and to ease the explanation of operations. A user can access the developed system through the web browsers such as the Microsoft Internet Explorer and Google Chrome as long as the Java Runtime Environment and OpenGL are installed. Three general configurations of five-axis milling machine tool have been implemented including Head-Head, Head-Table, and Table-Table. Furthermore, five-axis post-processing is generally a bottleneck in the popularization of toolpath simulation. An intelligent distributed agent-based post-processor has been integrated in this system. For example, an APT file created by the usage of Catia CAD/CAM software according to a five-axis toolpath could be post-processed by the developed system for the generation of a five-axis NC program. This NC program could then be simulated in the proposed system. The developed system has been successfully implemented and shown very promising application in the understanding of five-axis milling operation.

Development of a Virtual Milling Machining Center Simulation System with Switchable Modular Components

The application of traditional three-axis milling machine center is very popular and the related application technology is also much matured resulting in mechanical components to be machined with good quality. Machine tool has therefore become an inevitable facility in precision manufacturing. Furthermore, the pursuit of higher precision machining has thus demanding five-axis machine tool to be adopted owing to its flexibility and capability in machining more precise mechanical components in shorter time. However, one of the key factors for the popularity in smooth introduction of five-axis machine tool would be based on a very user friendly learning and teaching environment. This is partly because two more rotational axes in a five-axis machine tool could generate very complex toolpath movement that is out of the imagination of a general operator. Furthermore, the price of an industrial five-axis machine tool is not normally affordable by an educational institute; to the worse, the maintenance cost is also very high. There is very high risk for a novice to collide during the learning process and this will generally cause big worry of a teacher. This paper aims for the development of a virtual machining center simulation system with switchable modular components to ease the learning process in getting acquainted with a five-axis machine tool. A five-axis machine tool consists generally of two modules: (1) CNC controller and Operation panel, and (2) machine tool hardware. The developed system will provide the novice with four CNC controller with operation human machine interface (HMI), and three typical types of five-axis machine tool, Head-Head (HH), Head-Table (HT), and Table-Table (TT), are also supported. The developed modularized and switchable machining center simulation system has been successfully developed and is very helpful to both learner and teacher

Five-Axis NC Program Conversion for Inclined Plane Machining

Machining processes on an inclined plane include mostly hole making, profiling, and pocketing. It comprises of 80% - 90% cutting process in five-axis machining and is therefore very important in multi-axis machining work. However, five-axis machining processes are normally difficult to introduce and to use because five-axis CAD/CAM and post-processor are normally demanded to generate five-axis NC program even though it is for the 2D contour machining on a plane with inclined angle. Therefore, this paper studies the inclined plane machining methods and extends traditional three-axis milling machining processes and methods so as to directly convert 2-1/2 and three-axis NC program into five-axis machining program to ease the application of five-axis machining processes. This study integrates the developed three-axis NC program interpreter, inclined plane coordinates transformation, and post-processor to simply the inclined plane NC programming. Two-dimensional NC program on a plane can be converted into five-axis NC program on the inclined-plane by the proposed methodology. Case study has been utilized to verify the utilization and correctness of the proposed methodology

Studies on the Exchangeability of Different APT Interpreters for 5-Axis Machine Tool Applications

Generally, the NC format is the description for the positioning and/or the movement of its linear and rotary axes. As the multi-axis machine tools have a variety of configurations, their NC codes are not exchangeable. This issue leads to some inconvenience and confounding in the manufacturing processing schedule. Furthermore, when the specifications of tool such as length, diameter or shape are reset, the NC program must be regenerated accordingly. That is to say, the exchangeability of NC program among different five-axis machine configurations is an important issue in making better usage of industrial five-axis machine tools for efficient applications. An APT program records the tool path, tool vector and cutting information, etc. In particular, the recent development of APT format can provide the capability recording the motion posture of the tool such as the tool orientation, the position and its normal vector of the tool contact point. Therefore, it can solve the problems of the exchangeability for the different machine tools as well as the online resetting of tool specifications, even the tool posture. In this paper, a new method was proposed to interpret the APT code into tool movement data including toolpath, location, tool orientation, the contact point and its contact vector, etc., which can be applied to the conversion of different NC codes, or be connected to the controller of the machine tool so as to proceed the interpolation calculation for directly machining control. Moreover, the application scope can be extended to the verification of machining and to drive a virtual machine tool for previewing. Since the APT format varies according to different CAD/CAM systems, a common intermediate interchange standard (CMIS) was proposed, designed and verified in this paper as a feasible solution for the exchangeability of different APT formats. The process of the proposed method includes interpreting a variety of APT program into a common standard format, and then transforming this intermediate standard code into various NC programs for the corresponding machine configurations. An example was used to demonstrate how to convert an APT generated by CATIA software into intermediate code for a Table-Table five-axis machine tool with two rotary axes attached on table (XYZAC configuration). As the APT contains the definition of inclined plane, so the homogeneous coordinate transformation was adopted to transform the coordinate system of the inclined plane into the work coordinate system; it was further transformed into the corresponding NC program via an inverse kinematics transformation. This example has shown the feasibility of the method proposed. Moreover, the research can be applied not only to the exchangeability of different APT format but also to the other related applications such as the verification of machining error and the drive of virtual machine tool.

Development of KM-based AHP method and auxiliary web questionnaire system for multi-criteria decision-making application

The analytic hierarchy process (AHP) method has be proposed and popularly applied in many disciplines over three decades. In the same time, many scholars also suggested various improved methods to enhance the decision quality. For the more delicate decision-making, it is necessary to provide more accurate and abundant reference information for the decision-maker. However, traditional AHP related questionnaires are insufficient for providing enough information and a friendly environment. In this paper, we proposed a KM-based AHP decision-making method to provide the questionnaire designer a guideline or reference and developed an auxiliary web questionnaire system based on this method. A case study of selecting a machine center was illustrated the implementation and applicability of this method, a mold manufacturing company was invited as the survey objective. This method proposed in this research is general in form and can be applied to the other multi-criteria decision making cases.

The Development of an APT Program Interpreter for 5-Axis Machining

As there are various machine configuration and frequent changes of cutter orientation in 5-axis machining, the standard NC codes are not inter-exchangeable among machines. This phenomenon induces a lot of cutting difficulties and machining problems such as the inconvenient working process for operators and very low cutting efficiency. At present, some advanced machine controllers already can accept the APT code besides NC code to increase the cutting flexibility. They also offer some advanced machining functions such as tool center point control and spatial compensations of tool, etc. By way of APT interpreting, the common controller can also implement these advanced functions. Besides, CAD/CAM software also supports APT post-processor to generate NC code for different machine configurations. This means the application of ATP program has played an important role in five-axis machining. However, although CAD/CAM software supports the interpretation of APT program as a core key technology of five-axis machining, the manufacturers of controller with advanced functions are unwilling to open their system. Up to now, there has been few related research papers published on this topic. In this paper, we proposed an APT interpretation method for five-axis machining. This method includes seven functional modules and related implementing procedures. A case study has been adopted to demonstrate the feasibility of the proposed method. The research result could be adopted as a reference to develop the value-added technology in 5-axis machine tool application for academy and industry.

Design and construction of a Virtual Reality wire cut Electrical Discharge Machining system

Wire Electrical Discharge Machining (WEDM) uses a metallic wire to cut a product profile such as extrusion dies and blanking punches. The cost of possession and maintenance of the WEDM equipment is generally high. Hence, it is important to reduce the machine operation training cost, to provide simulation verification, and to investigate the correctness of the NC codes. This paper presents the development of a Virtual Reality (VR) based WEDM system which can emulate a real WEDM machine. The research result can be adopted to serve as a cost-effective tutoring system that has the benefits of improving the inefficient and dangerous drawbacks in operating the real machine. The developed system can provide an effective application in digital education and training environment for academics and industries.