Lian-yi Chen

A dental training system using virtual reality

There are problems with the lack of reality in dental training using a mannequin. In dealing with such problems, we suggest in this study a dental training system with application of virtual reality technology. In our system, a virtual environment and a virtual patient were produced in a virtual space, in which dental mirror and hand pieces can be operated in real time. To be aware of and to avoid possible dangers in training, the tongue of the patient is moved randomly. A warning sound is given off when the drill comes in contact with the tongue or the buccal. The effectiveness of the system was confirmed with experiments. Furthermore, the application of force, which is very important in dentistry, was tried, and the avoidance of a strong force affecting the tongue or buccal was also realized. Finally, the feather-touch training in tooth cutting was carried out, in which the acquisition of force information and the visualization of force were realized.

A preliminary Research on Analysis of Pulse Diagnosis

Pulse diagnosis has been one of the most important diagnosis methods in the orient medicine. Pulse taking is carried out by putting fingers on the radialis artery, diagnosing the patient from the feeling transferred to the finger by pulsation of the artery. Because pulse diagnosis is very sensitive, requiring high level of skill and long experience, it is mostly difficult for a trainee to master. It is also a problem that pulse diagnosis is such a technique depending mostly on the feelings of separate doctors without a clear standard. In this study, the vibration of the surface of the skin caused by pulsation of the artery was measured as a method of settlement of the above issue points, and the development of the device to analyze pulse taking quantitatively was tried.

Proposal of a concept of future oriented machine tools for advanced manufacturing systems

In order to satisfy the recent various consumers’ needs, an advanced manufacturing system will be required. So, the innovative concept of Future Oriented Machine Tools (FOMT), which consists of four function blocks to realize the advanced manufacturing system, is proposed. The four function blocks are Management, Prediction, Observation and Strategy, and intelligent manufacturing processes are realized by utilizing these function blocks. FOMT can make a significant contribution in four stages: design stage, production scheduling stage, machining stage and post-machining stage. In the design stage, the product information such as accuracy can be evaluated in CAD, considering the manufacturing ability concurrently. In the production scheduling stage, the product schedules can be generated automatically and flexibly for the various products. In the machining stage, cutting conditions adjusted autonomously according to the machining status and machining problems. In the post-machining stage, the machining know-how data are accumulated and stored for future production and human engineers. The feasibility of it, especially the machining stage, is discussed using the developed cutting process simulator called VMSim (virtual machining simulator) from the view points of cutting force, machining error and environmental burden (CO2 emission).

Development of CAPP system for removal operation of 3D free surfaces

The authors deal with the development of a computer aided process planning system (CAPP) for manufacturing products having 3D free-form surfaces. It is difficult to perform a form feature modeling of free-form surfaces, and to clear the relationship between the removal form and cutting tool form. To solve these problems, the authors extract the concavity of the product model by paying attention to the product concavity. Considering that the concavity is the most important part in the machining of the free surface, a local concavity model is produced by judging concavo-convex. This model is analyzed and characterized with geometric shape and machining conditions. The connection relationship between each area is represented as graphs. The authors carried out the process planning using the form feature model.<<ETX>>

A STUDY ON CALCULATION METHODS OF ENVIRONMENTAL BURDEN FOR NC PROGRAM DIAGNOSIS

ABSTRACT Some activities for environmental protection have been tried to reduce environmental burdens in a lot of fields. Manufacturing field is also required to reduce them. Hence, prediction system of environmental burden for machining operation is proposed based on LCA (Life Cycle Assessment) policy. This system can calculate environmental burden (equivalent CO2 emission) due to the electric consumption of a machine tool, the cutting tools status, the coolant quantity, the lubricant oil quantity and the metal chips, and provide the information of the accurate environmental burden of the machining process by considering some activities related to the machine tool operations. In this paper, the development status of prediction system is described. As a case study, two NC programs that manufacture simple shape are also evaluated to show the feasibility of it.

Proposal of Modification Strategy of NC Program in the Virtual Manufacturing Environment

Virtual manufacturing will be a key technology in process planning, because there are no evaluation tools for cutting conditions. Therefore, virtual machining simulator (VMSim), which can predict end milling processes, has been developed. The modification strategy of NC program using VMSim is proposed in this paper.

Human oriented form feature modeling and process planning using virtual reality

Reports the application of visual functions and data-glove input of virtual reality (VR) technology to a process planning system based on form feature modeling. The system proposed applied VR technology and connects organically the computer with the human beings. It is noticed that an operator can treat objects in a virtual 3-dimensional (3D) spaces with his hands while watching them with his eyes. The form features are directly modeled and applied to process planning with reality, by real-time feedback.<<ETX>>

Analysis of Disassembled Module with Damage Model for Recycling

As environmental problems have become more serious, a sustainable society is necessary. To realize the inverse manufacturing system the prime problem is how to improve the rate of reusing the product modules. Therefore analyzing the life-time of the disassembled modules is very important before reassembling process. In this paper, a cumulative damage model is proposed to discuss the quality of the product that is assembled by reuse modules. It is supposed that modules suffer damages due to shocks and fails when the cumulative damage level exceeds the failure level. Then maintenance cost will be analyzed in order to minimize the expected maintenance cost-rate by optimal maintenance time T and optimal number of damages N in this cumulative damage model. The probable safe life-time of module reuse will be explored. Finally numerical examples are given to confirm the validity of the proposed model.

Cost Prediction System Using Activity-Based Model for Machine Tool Operation

Production cost is one of the most important factors for manufacturing. The production cost associated with each machine tool is calculated from total cost of factory in general. The operation status of machine tools, however, is different, so accurate production cost for each product can’t be calculated. Hence, accounting method of production cost for machine tool operation is proposed using the concept of Activity-Based Costing and is embedded to virtual machining simulator for the cost prediction.

Feature Extraction from Object with Free Form Surfaces.

In recent years, industrial goods and consumer products, for example, telephones and cameras, have been made of three-dimensional free form surfaces. The free form surfaces should be comfortable at the interface between human and machine. It is predicted that the elaborate design will become principal parts of the products. This paper deals with a new method for extracting features from the three-dimensional object with free form surfaces. The method deals with extracting a form feature from a convex hull of the object and machining features from the objects concavity. The convex hull is calculated by means of an outermost point method and expanded in a series of spherical functions. The concave areas are characterized by diameters and directions of tools which remove the concave areas during machining processes.