Shozo Takata

Maintenance : Changing Role in Life Cycle Management

As attention to environmental problems grows, product life cycle management is becoming a crucial issue in realizing a sustainable society. Our objective is to provide the functions necessary for such a society while minimizing material and energy consumption. From this viewpoint, we should redefine the role of maintenance as a prime method for life cycle management. In this paper, we first discuss the changing role of maintenance from the perspective of life cycle management. Then, we present a maintenance framework that shows management cycles of maintenance activities during the product life cycle. According to this framework, we identify technical issues of maintenance and discuss the advances of technologies supporting the change in the role of maintenance.

Open Controller Architecture – Past, Present and Future

Abstract Open Control Systems are the key enabler for the realization of modular and re-configurable manufacturing systems. The large number of special purpose machines and the high level of automation have led to an increasing importance of open control systems based on vendor neutral standards. This paper gives an overview on the past, present and future of Open Controller Architecture. After reflecting on the different criteria, categories and characteristics of open controllers in general, the CNC products in the market are evaluated and an overview on the world-wide research activities in Europe, North America and Japan is given. Subsequently the efforts to harmonize the different results are described in order to establish a common world-wide standard in the future. Due to the “mix-and-match” nature of open controllers concentrated attention must be paid to testing mechanisms in the form of conformance and interoperability tests.

Sustainability in manufacturing: Recovery of resources in product and material cycles

Global Framework.- Life Cycle Engineering and Management.- Product Development.- Processes and Tools for Disassembly.- Planning for Remanufacturing and Recycling.- Enabling for Sustainability in Engineering.- Roadmap.

A Cutting Simulation System for Machinability Evaluation Using a Workpiece Model

Abstract This paper describes a cutting simulation system to be used in the evaluation of machinability of products at various stages of the manufacturing processes. The system developed consists of geometric simulation and physical simulation. The geometric simulation is performed by using extended Z buffer models representing a workpiece and a tool swept volume. In the physical simulation, instantaneous cutting force vectors acting on a square end mill are computed based on the am of chip element removed by a thin divided section of a flute. The tool deflection induced by the cutting force is then calculated. The result is used to estimate the machining error caused by tool deflection. A series of cutting experiments are conducted to verify the effectiveness of the system.

Operation Planning Based on Cutting Process Models

Abstract This paper describes model based operation planning for pocket milling operations. The tool path and cutting conditions are determined based on the geometric model of workpieces and the physical models of the cutting process. The tool path is generated by using the Voronoi diagram of a cutting area. Cutting conditions to achieve the maximum metal removal rate are determined by evaluating the physical models of cutting torque, chatter vibration, and machining error. To maintain a favorable cutting state, the radial depth of cut is controlled by modifying the tool path distance at the circle path segment and by adding additional tool path segments at the corner. Examples are shown to demonstrate the effectiveness of the method.

Analysis of surface roughness generation in turning operation and its applications

Summary Surface roughness generation in a turning operation is examined by using a FFT analyzer. It is found that the roughness profile of a workpiece is composed of several periodical components: the cutting tool feed component, the spindle rotational error component, and the chatter vibration error component. A block diagram of surface roughness generation in a turning operation has been drawn to give a clear illustration of the process. To examine the origin of these error components, a series of cutting tests were carried out with different spindle bearing arrangements and with different types of workpiece material. It has been shown that the method presented in this study is very helpful in evaluating the machinability of workpiece material and also in diagnosing the conditions of the machine tool spindle system.

Advances in Life Cycle Engineering for Sustainable Manufacturing Businesses

Life cycle engineering explores technologies for shifting industry from mass production and consumption paradigms to closed-loop manufacturing paradigms, in which required functions are provided with the minimum amount of production. This subject is discussed from various aspects: life cycle design, design for environment, reduce-reuse-recycle, life cycle assessment, and sustainable business models. This book collects papers from the 14th International CIRP Life Cycle Engineering Conference, the longest-running annual meeting in the field.

Real-time drill wear estimation based on spindle motor power

Abstract In-process detection of drill wear is one of the most important technologies for unmanned machining systems. This study examines and proposes the method of on-line drill wear estimation based on spindle motor power consumption during the drilling process. Integration of the drilling process model with the spindle drive system model is the key feature of the proposed method. The drilling process model describes the relationship between drill wear and drilling torque, whereas the spindle drive system model describes the relationship between drilling torque applied to motor and spindle motor power. Evaluation tests have shown that the proposed method is a good real-time estimator for drill wear.

A System for Monitoring the Machining Operation by Referring to a Predicted Cutting Torque Pattern

Summary A system for predicting the cutting torque by using a geometric modelling system, and its application to verification of NC data and monitoring of the cutting process are described in the paper. The cutting process is simulated geometrically in a modelling system. Based on data obtained from the geometrical simulation and on technological data of the NC program, the cutting torque is estimated, by using an empirical equation, as a linear combination of the volume of the removed material and of the tool-workpiece contact surface area. The torque measured in the experiments was in good agreement with the preliminarily estimate. The system also proved to be applicable when machining a cast part with geometrical inaccuracies within a few millimeters.

Generation of a Machining Scenario and Its Applications to Intelligent Machining Operations

A machining scenario is a description of a machining process in which the changes of machining states are described in terms of both geometrical and physical characteristics of machining processes such as geometry of tool-workpiece contact face, cutting force, and machining error. A machining scenario can be automatically generated by a model based cutting simulation. It provides useful information for pre-process optimization of cutting conditions. on-line adaptive control, and monitoring and diagnosis of abnormal occurrences. This paper describes the data structure of the machining scenario and how it can be utilized for the generation of efficient and reliable machining data and realizing intelligent machining operations. The results of experiments by a prototype system are also described to verify its effectiveness.