Grier C.I. Lin

Latest developments in CIM

Abstract Manufacturing enterprises play an important role in improving the economic environment of a country. The economic environment of many developed countries is under threat from emerging industrialised countries. Today, the capability of producing high quality products with shorter delivery times and the ability to produce according to the diverse customer requirements have become the characteristics required of order-qualifiers for manufacturing industries. Hence, application of intelligent manufacturing systems and computer integrated manufacturing (CIM) has become the necessity to overcome the above issues while retaining the employment level and revenue of a country in todays highly competitive global market. With the developments taking place in CIM and its related technologies, the application of CIM in manufacturing enterprises has become a reality. This paper focuses on latest research developments in CIM and a new CIM wheel proposed to satisfy the emerging technological application of virtual enterprises.

Development of a collaborative CAD/CAM system

Abstract This paper presents the development of a collaborative CAD/CAM system ( COCADCAM ). COCADCAM extends an existing single-location CAD/CAM system to a multi-location CAD/CAM application so that two geographically dispersed CAD/CAM users can work together on a three-dimensional CAD-geometry coediting and CAD-related tasks collaboratively and dynamically. COCADCAM dynamically supports CAD data communication that are not available in traditional single-location CAD/CAM. The dynamic data communication is achieved through the development of networking algorithms and CAD/CAM functions in this paper. The networking algorithms based on UNIX Interprocess Communication (IPC), the Network File System (NFS), and a connection-oriented client and server model under the Transmission Control Protocol/Internet Protocol (TCP/IP) suite. The CAD/CAM functions included surface modelling, simulation of a milling toolpath, and post-processing of an NC program following collaborative CAD-geometry coediting, which are directly or indirectly supported by the Application Programming Interface (API) of the CAD/CAM software. The networking algorithms and CAD/CAM functions together can facilitate an environment for CAD-geometry coediting and related tasks such as design, analysis and manufacture. COCADCAM has been successfully implemented through local area network (LAN) and the Internet; a remote machining cell is also linked so that the generated NC program based on a coedited free-form surface can be used for the physical machining operation. The algorithm proposed by COCADCAM can be referenced for the extension of other single-location CAD/CAM systems to multi-location applications.

Reverse engineering in the design of turbine blades – a case study in applying the MAMDP

Abstract This paper presents a case study on the reverse engineering of turbine blades used in nuclear power generators. Reverse engineering has been widely recognised as a crucial step in the product design cycle. However, major problems with current reverse engineering technology are the inefficient surface reconstruction process, lack of digitising accuracy control in the data digitisation process, and bottlenecks resulted from huge amounts of digitised surface points in the surface modeling process. Moreover, under this limitation, modern concurrent engineering concepts are difficult to implement to obtain optimal product design. This study applies a developed reverse engineering approach – the modified adaptive model-based digitizing process (MAMDP) to the 3D geometric design of turbine blades. The approach integrates surface digitising and modeling processes of turbine blades into a single surface reconstruction process. Using the approach, accurate product CAD models can be efficiently generated and the product design cycle of turbine blades can be successfully linked.

CAD/CAM collaboration and remote machining

This paper presents a collaborative CAD/CAM system which extends a single-location CAD/CAM technology to multi-location application in collaboratively and interactively coediting CAD geometry at a distance with the implementation of the UNIX interprocess communication and a connection-oriented client and server model. This system can output NC program following collaborative discussion and facilitate a collaborative design, analysis, and manufacturing system between remote locations in forming a virtual remote machining unit underpinned by a single-location CAD/CAM environment through Internet or Integrated Services Digital Network (ISDN). Examples are used to illustrate this development that can be used in the final stage CAD refinement and can be further extended for multi-location CAD/CAM collaboration.

An integrated reverse engineering approach to reconstructing free-form surfaces

Abstract An integrated reverse engineering approach to generating free-form surfaces has been developed to create CAD-compatible free-form surface models with a coordinate measurement machine and a touch trigger probe. The approach integrates data digitization and surface modelling to obtain an efficient and accurate digitization process with a collisionfree exploration path, and to reconstruct least-squares bi-cubic B-spline surface models for rapid product prototyping. The whole approach is divided into two stages: the planning of boundary digitization; and the adaptive model-based digitizing process (AMDP). The planning of boundary digitization defines the exploration surface region. The AMDP then automatically explores the whole measured surface region with a collision-free exploration path, continuing until a satisfactory surface model corresponding to the users specified digitizing accuracy is obtained. This approach significantly reduces the product development lead time and obtains a surface model with controlled digitizing accuracy. The validity and applicability of this approach are demonstrated by three practical industrial examples.

A world class new product development best practices model

Past research provides evidence of a wide range of antecedent variables to explain new product development performance. The reported determinants are a combination of strategic, development process, organizational, and market factors. However, these research efforts are fragmented and focus on one or two key factors. Researchers look at this issue from a narrow disciplinary perspective. So the results are quite discipline-biased. Apart from the lack of a multi-disciplinary approach, there is a real gap in subjecting these factors to rigorous empirical tests, and incorporate modern proven best practices of world class innovative companies to guide practitioners in their innovation journey. There is a real need to broaden the range of factors considered and develop an integrated model with high predictive power to guide new product development (NPD) efforts. This paper aims to address this research issue. In this research study, four key factors have been identified in modelling financial performance in NPD. They are strategic fit and shared vision, market orientation, stimulus and slack time, organization for collaboration and communication. Regression analysis was performed to validate their importance and estimate the parameters of these four key factors. The result shows that all these four factors are statistically significant in determining financial performance in NPD. This framework can be used practically to assist managers to improve in their NPD efforts so as to achieve higher financial return on investment.

A vision-aided reverse engineering approach to reconstructing free-form surfaces

Abstract A vision-aided reverse engineering approach (VAREA) has been developed to reconstruct least-square free-form surface models from physical models, with a coordinate measurement machine (CMM) equipped with a touch-triggered probe and a computer vision system. The VAREA integrates computer vision, surface data digitization and surface modelling into a single process. Two main steps are applied in this innovative approach. The initial vision-driven surface triangulation process (IVSTP) generates a triangular patch by using stereo image detection and a constrained Delaunay triangulation method. The adaptive model-based digitizing process is then used to refine the surface reconstruction and to control accuracy to within user-specified tolerances. As a result, a least-squares bicubic B-spline surface model with the controlled accuracy of digitization can be obtained for further application in product design and manufacturing processes. More than 85% reduction has been achieved in the time required to construct free-form surfaces using this approach, as compared with traditional manual methods with CMM. Therefore, product design lead time can be significantly reduced.

Rapid and flexible prototyping through a dual-robot workcell

Abstract With the advancement of CAD/CAM and robot technologies, applying robots for rapid prototyping applications has become a growing trend. However, a single robot can only perform limited prototyping tasks. Compared to a single robot, a dual-robot workcell can have greater structure flexibility, production efficiency, and system reliability due to the inherent parallelism and duality of robots. This paper presents the development and implementation of a dual-robot workcell for prototyping of 3D models. First, kinematic models of both robots in the workcell are established. Then, the concepts of five-axis machining configurations, postprocessing, off-line robot path generation and the dual-robot control scheme are presented. Finally, details of cutting experiments are provided to demonstrate the effectiveness of the system. The results show that the proposed dual-robot workcell is flexible and efficient for prototyping complex components in the current industrial environment.

An on-line relative position and orientation error calibration methodology for workcell robot operations

Abstract Relative position and orientation inaccuracy always exists between a robot and the equipment with which it operates, especially in batch-type production cells that are subjected to dynamic changes. This inaccuracy causes robot relative positioning errors, and may even result in operation failure if the off-line programmed moving path is implemented without adjustment. To make use of off-line programming and simulation tools, an on-line calibration methodology for robot relative positioning inaccuracy was developed in this study. This methodology eliminates the need for time-consuming off-line calibrations relying on accurate models and expensive devices. An industrial robot system was enabled to detect and compensate automatically for relative positioning errors by incorporating a vision system, a 3-D force/torque sensor, and control strategies involving neural networks. The experimental results showed that this methodology is valid and robust in calibrating the relative position and orientation errors automatically without the need for mathematical models and complex off-line calibration procedures for model parameters. Consequently, batch-type production cells would be more flexible, adaptable and intelligent in accommodating dynamic workcell changes with less human effort.

STEP-based product modeling system for remote collaborative reverse engineering

Abstract Production of high-quality products with lower cost and shorter time-to-market is an important challenge in the face of increased global competition, and reverse engineering plays an important role in accelerating product and process development. With the advent of new technologies such as network, multimedia and product data exchange standard STEP (STandard for Exchange of Product model data), there are many advantages to adopt these technologies to enhance the competitiveness of an enterprise. In this paper, a product information recording module for reverse engineering is developed to enhance the performance of product development. A STEP development tool, ST-Developer, and Visual C++ were used to develop this module, which can be used to record key information expeditiously during a collaborative process, and can also be used for further exchange of information, or as the basis for manufacturability evaluation. In this paper, the developed STEP-based information recording system is further integrated with the conventional Computer Supported Cooperative Work methods such as videoconferencing and application-sharing to form a remote collaborative reverse engineering system, which can provides a new strategy for an enterprise to speed up the product development cycle, reducing production cost, as well as sharing knowledge and experience.