Liu Wen-jian

An Internet-based system for setup planning in machining operations

Setup planning is a complex and intuitive process. An efficient setup planning system is essential to cut costs and to reduce lead-time. In this paper, an integrated system based on Internet for setup planning is presented. The system is implemented based on a simple three-tier thin client-fat server architecture. The utilizing of (extensible modeling language) XML as a file format provides means for the transfer of information between various manufacturing systems. A methodology for setup planning is also presented, and in which the machining precedence, tolerance requirement and fixturing constraints are taken into consideration. Hence, a practical and global optimal setup plan along with fixturing features in each setup will be generated by this methodology. A case study is presented to illustrate the proposed system and to show the effectiveness of the presented setup planning methodology.

An Internet-Enabled Setup Planning System

In this paper, an Internet-enabled system has been developed to support setup planning, based on some state-of-the-art Java and Web technologies. The utilizing of XML as a file format provides means for the transfer of information between various manufacturing systems. A fuzzy set theory based intelligent approach for setup planning is introduced. In this approach, the setups are automatically planned based on key factors of machining practice, tolerance requirement and manufacturing cost. Finally, a case study is presented to illustrate the proposed system and to show the effectiveness of the presented setup planning approach

A Novel Modular Fixture Design and Assembly System Based on VR

Modular fixtures are one of the important aspects of manufacturing. This paper presents a desktop VR system for modular fixture design. The virtual environment is designed and the design procedure is proposed. It assists the designer to make the feasible design decisions effectively and efficiently. A hierarchical data model is proposed to represent the modular fixture assembly. Based on this structure, the user can manipulate the virtual models precisely in VE during the design and assembly processes. Moreover, the machining simulation for manufacturing interaction checking is discussed and implemented. Finally, the case study has demonstrated the functionality of the proposed system. Compared with the immersive VR system, the proposed system has offered an affordable and portable solution for modular fixtures design

An agent-based system for multi-project planning and scheduling

In multi-project environment, multiple project groups share and compete for the limited resources to achieve their own goals. In order to address the dynamic requirements of multi-project production, this paper develops a multi-project planning and scheduling system using a distributed multi-agent approach. The hybrid framework of system is presented and discussed with detail. This framework consists of six types of agents facilitated with different functionalities. These generic agents are dynamically deployed and customized at each location where a project is executed. Further more, a negotiation-based multi-project planning and control mechanism is developed to coordinate these distributed agents. Through which a predictable and nearly optimal scheduling with agility and adaptability can be realized in distributed multiple projects manufacturing environment. Finally, a prototype system was implemented upon this framework, and was validated in an aerospace company.

Notice of Retraction A new manufacturing scheduling system model and its implementation

In order to adapt to the requirements of manufacturing scheduling system in an aerospace enterprise, a new manufacturing scheduling system was put forward according to the actual situation of the aerospace enterprise, which plays a key role in manufacturing enterprises. And a new manufacturing resources organization model-manufacturing resources organization model based virtual manufacturing cell (MROM-VMC) was proposed, which is the foundation of this new manufacturing scheduling system. First of all, the function structure of the manufacturing resource model was designed, and the procedure of VMC formation was given. In addition, the hybrid framework of the production scheduling system model was established; the working process of this model was presented. Finally, an application case in a manufacturing enterprise was provided to validate that this system is able to simplify the procedure of scheduling and improve production efficiency and quality.

Intelligent setup planning in manufacturing by fuzzy set theory based approach

In this paper, a fuzzy set theory based intelligent approach for setup planning in manufacturing is introduced. The setup planning problem is decomposed into three sub tasks in the proposed approach: the setup generation, operation sequence and setup sequence. The setups are generated according to the optimal machining direction of each feature, which is determined by fuzzy comprehensive judgment method. Using production rules and fuzzy set theory, the feature precedence relationships matrix (FPR) is formed by considering the main influence factors such as feature geometry, datum relationship, heuristic rides and manufacturing cost. Based on the FRP, the operation sequence and setup sequence problems are mapped onto traveling salesman problem (TSP). The Hopfield neural networks based algorithm is adopted to execute these subtasks. An example is illustrated to demonstrate the proposed approach.

Integration of CAPP and CAFD based on agent technology

This study intends to propose an intelligent system with agent technology in order to realize integration of computer-aided process planning (CAPP) and computer-aided fixture design (CAFD). The agent-based system framework, in which various intelligent agents worked together to perform process planning and fixture design tasks in an autonomous and collaborative way, was put forward. The system consisted of two categories of agents and functional definition of each intelligent agent was presented. Moreover, communication mechanism and XML-based information exchange method between agents were proposed. Finally, an intelligent algorithm based on fuzzy comprehensive evaluation was designed to resolve competition conflicts between agents.

An Intelligent Methodology for Business Process Model Verification

In order to verify the correctness of business process model, A-Net modeling based on activity was studied and a multilevel verification model based on knowledge rules was established. An extended structure of knowledge rule was proposed and a flowchart was presented for the multi-level verification model. Moreover, a modified genetic algorithm was proposed to resolve the resource scheduling conflicts checked by the verification model. The structure and flowchart of the modified genetic algorithm were designed. Finally, an illustrative example was proposed and the verification model was proved feasibility and efficient.

An intelligent system of setup planning on Internet for metal cutting

This paper presents an intelligent system to automate the task of setup planning in the Internet environment. The requirements of a setup planning system are discussed and how the proposed system meets the requirements is also described. In developing the system organization, WWW technology, including the XML markup language and Java programming language is utilized. By that, the seamless integration of setup planning system with other manufacturing systems is realized. Furthermore, a multi-objective optimization approach based on fuzzy set theory for setup planning is introduced. In this approach, the setup planning problem is decomposed into three subtasks, namely the setup generation, operation sequence and setup sequence. A combination of fuzzy evaluation and Hopfield neural networks based algorithm are adopted to execute these subtasks. Finally, we provide an illustrative example regarding the usage of the proposed system.

Improved MMAS for Multi-Process Routes Decision-Making

This study intends to propose an intelligent system with the integration of workflow modeling technology and max-min ant system (MMAS) in order to realize visualization and intelligence of computer aided process planning (CAPP). Workflow modeling technology was applied to represent multi-process routes decision-making problem (MRDP) and a modified ant colony algorithm was proposed to exploit the best solution by improved max-min pheromone strategy and the way of updating pheromone. Finally, simulation results were reported and the proposed algorithm indeed had admirable performance for MRDP.