An intelligent modeling and analysis method of manufacturing process using the first-order predicate logic

Manufacturing process refers to machining sequence from raw materials to final products. Process plan has important effects on manufacturing process. In general, process designer relies on his experience and knowledge to arrange the process plan. For a complex part, it takes long time and effort to determine process plan. In this paper, an intelligent modeling and analysis method using the first-order predicate logic is proposed to evaluate the manufacturing performance. First, the logic predicates used to represent the process plan are defined according to the machining methods, and the predicate variables are discussed in detail. Consequently, the process plan can be represented in the form of the first-order predicate logic. Second, a type of element model composed of four nodes and four links is put forward in order to construct the process model. All components in this element model are respectively explained, and the mapping relationship between element model and predicate logic is described in detail. According to engineering practices, logic inference rules are suggested and the inference process is illustrated. Hence, the manufacturing process model can be constructed. Third, the process simulation is carried out to evaluate the performance of manufacturing system by using measures such as efficiency, the machine utilization, etc. Finally, a case study is given to explain this intelligent modeling method using the first-order predicate logic.     

The use of intelligent feedback for work order release in an uncertain manufacturing system

A turbulent manufacturing environment where uncertainty is inevitable does not allow for the availability of the required materials and resources when they are needed. This paper studies the implications of demand surges, lead-time variations and resources breakdown on the ability of a manufacturing system to achieve its delivery target. Simulation modelling was used to represent a stochastic manufacturing system, which is disturbed by these uncertainties. Manufacturing systems each with and without intelligent feedback were modelled. An intelligent feedback is represented via a set of algorithm, which reanalyse and self-organise the new status of the order in the presence of the uncertainties and update the relevant attributes before the order is released. Four types of intelligence were examined: (1) lead-time allowance, (2) capacity allowance, (3) safety stock allowance and (4) batching flexibility. Experiments results from each system were compared. It was found that the manufacturing system with intelligent feedback has a higher ability to achieve its delivery target by proactively tackling the variations caused by uncertainties. This study also found that the reliability of a work order in the presence of uncertainty could be improved by using an appropriate type of intelligence, which is dependent upon how and when the order was released. It was concluded from this research that intelligent feedback could help manufacturing enterprises proactively readjust the release of work orders that will be affected by uncertainties in order to improve the reliability and delivery of work orders.     

An intelligent grouping algorithm for cellular manufacturing

The methodology presented in this paper will provide a means of identifying part families/machine cells using design and manufacturing characteristics simultaneously. The technique used is a self-organizing neural network called interative-activation and competition (IAC) which acts as a content-addressable memory. This neural network is used to define a similarity index of the pairwise comparisons of parts based on a variety of design and manufacturing characteristics. A bond energy algorithm partitions the matrix of part similarity indices to create part families and inferred from the part families are machine cells. A brief example will be examined as well as discussion of the results.     

Offshoring manufacturing: Implications for engineering jobs and education: A survey and case study

One result of globalization is the rapid growth of offshoring, i.e., the outsourcing of functions and jobs to offshore locations. In the USA, offshoring has progressed to the point where it already affects everyday lives, from the cars we drive (of which a large portion of the work and components are outsourced) to computers (which are typically manufactured offshore and shipped back to the USA), to electronic diagnostics (where calls are answered overseas). This phenomenon has implications on our lives and on the jobs that engineers and scientists will assume both now and in the future. Further, it is something that all highly developed and even some lesser-developed countries must face. Consequently, the growth of outsourcing will have a major impact on the educational objectives of engineering programs and the resultant engineering curricula worldwide.

This paper presents recent data on product and job offshore migrations and discusses the various dimensions of this phenomenon. In addition to the potential loss of engineering and other high-end technical jobs, sociological and cultural aspects, intellectual property issues, strategic planning concerns, and macro-economic issues are presented. For example, the effects of offshoring on the societal fabric of the countries that are recipients of manufacturing and service center outsourcing, such as China and India, are significant, rapid, and controversial. Offshoring has also begun to change the way that engineering programs in these countries educate their students. In addition, intellectual property issues create a major risk to companies considering outsourcing to certain less-developed countries. These issues can be broadly categorized into: the robustness and strength of intellectual property laws, and the degree to which these laws are implemented and enforced. Further, such factors as currency fluctuations and geo-political conditions can substantially impact outsourcing decisions and profitability.

The phenomenon of offshoring, which is now affecting engineering careers, will play a major role in shaping engineering education worldwide. The next generation of engineers will need to possess the ability to work seamlessly across cultures, have outstanding communication skills and be familiar with the principles of project management, logistics, and systems integration. Some educational models that begin to address these requirements will be presented.     

Distributed and intelligent information access in manufacturing enterprises through mobile devices

Due to the distributed nature of todays enterprises and the growing number of employees who are mobile, newer models of communication are required to cater to the information needs of manufacturing personnel. Mobile applications such as information alerts, disconnected information processing and background processing are applications gaining significant attention in manufacturing companies. In this paper, we describe the framework and architecture of a mobile-agent-based system, which provides mobile information services to the workforce in motion in manufacturing enterprises. We emphasize on background and disconnected processing and demonstrate the use of a Mobile-agent-based system to achieve it. Recognizing the need to exchange information between various distributed information sources, we explore the use of XML-based agent communication and discuss how XML can be used for inter-agent communication. We describe the design and implementation of a prototype system and discuss application scenarios.     

An integrated modelling framework to support manufacturing system diagnosis for continuous improvement

This paper proposes an integrated modelling framework for the analysis of manufacturing systems that can increase the capacity of modelling tools for rapidly creating a structured database with multiple detail levels and thus obtain key performance indicators (KPIs) that highlight possible areas for improvement. The method combines five important concepts: hierarchical structure, quantitative/qualitative analysis, data modelling, manufacturing database and performance indicators. It enables methods to build a full information model of the manufacturing system, from the shopfloor functional structure to the basic production activities (operations, transport, inspection, etc.). The proposed method is based on a modified IDEF model that stores all kind of quantitative and qualitative information. A computer-based support tool has been developed to connect with the IDEF model, creating automatically a relational database through a set of algorithms. This manufacturing datawarehouse is oriented towards obtaining a rapid global vision of the system through multiple indicators. The developed tool has been provided with different scorecard panels to make use of KPIs to decide the best actions for continuous improvement. To demonstrate and validate both the proposed method and the developed tools, a case study has been carried out for a complex manufacturing system.     

An object-oriented manufacturing control system

This paper presents the development of an event-driven control architecture and its implementation in a physical simulator of a computerized manufacturing system using object-oriented techniques. The architecture was developed to improve the efficiency of handling concurrent control events in the DOS environment. In the implementation, the control system of the physical simulator consists of four distinct layers of control devices: a PC/386 computer, a microcontroller, I/O modules and the system's control devices such as motors, solenoids and sensors. A control program residing in the PC/386 coordinates system-level tasks such as event scheduling, while a BASIC program running on the microcontroller handles all low-level control tasks such as sensor monitoring and motion control. The concepts and developments presented in this paper should help in implementing an efficient control system for both CIM systems and their physical simulators.     

IS: An intelligent scheduler for batch manufacturing systems

This paper describes the design and development of IS (for Intelligent Scheduler), a true multiple criteria knowledge-based scheduler which can be used for operational level scheduling of batch manufacturing systems, sometimes called job shops. IS incorporates a heuristic algorithm coupled with two knowledge bases, one for job scheduling and the other for selecting a suitable schedule based on the user provided criterion or criteria. With fourteen dispatching rules, it can generate both static and dynamic schedules. IS is a far more realistic and sophisticated model, accounting for many important factors, such as multiple machines, multiple fixtures, multiple tools, alternate processing routes, machine setup time, machine processing time, due date, job arrival time, initial shop loading, hot jobs, and considering either one criterion or multiple criteria simultaneously. In addition, IS coded in C and has all the features of a modern professional quality interactive program. It has moving bar and pull down menus and an on-line help function, a friendly human-computer interface, and an intuitive and easy to understand representation of the schedules.     

An agent-based service-oriented integration architecture for collaborative intelligent manufacturing

The rapidly changing needs and opportunities of today's global market require unprecedented levels of interoperability to integrate diverse information systems to share knowledge and collaborate among organizations. The combination of Web services and software agents provides a promising computing paradigm for efficient service selection and integration of inter-organizational business processes. This paper proposes an agent-based service-oriented integration architecture to leverage manufacturing scheduling services on a network of virtual enterprises. A unique property of this approach is that the scheduling process of an order is orchestrated on the Internet through the negotiation among agent-based Web services. A software prototype system has been implemented for inter-enterprise manufacturing resource sharing. It demonstrates how the proposed service-oriented integration architecture can be used to establish a collaborative environment that provides dynamic resource scheduling services.     

Scalability planning for reconfigurable manufacturing systems

Scalability is a key characteristic of reconfigurable manufacturing systems, which allows system throughput capacity to be rapidly and cost-effectively adjusted to abrupt changes in market demand. This paper presents a scalability planning methodology for reconfigurable manufacturing systems that can incrementally scale the system capacity by reconfiguring an existing system. An optimization algorithm based on Genetic Algorithm is developed to determine the most economical way to reconfigure an existing system. Adding or removing machines to match the new throughput requirements and concurrently rebalancing the system for each configuration, accomplishes the system reconfiguration. The proposed approach is validated through a case study of a CNC-based automotive cylinder head machining system.     

Human-computer interaction in manufacturing

The introduction of computers into the manufacturing environment has resulted in a significant impact on productivity and quality of manufactured products. Computers in manufacturing can be used to perform information processing, to control and monitor the manufacturing process, and to support the production operations in the plant. The use of computers does not, by itself, improve or degrade the skill levels required by operators. This is, in fact, a management function. Managers, product designers, and manufacturing personnel make choices to determine how machines and people will interact. When applied in the proper environment, computer-integrated manufacturing systems will increase machine utilization, reduce production cost, and improve productivity. The effective use of computers in manufacturing can be achieved by defining three major needs: manufacturing education, training, and research and development. This paper will study the elements of human-computer interactive systems and define requirements for proper use of computers in manufacturing.     

CIM—still the solution for manufacturing industry

In today's economic environment, enterprises that solely rely on traditional technologies cannot meet dynamic customer demands. Hence, proactive enterprises seek the application of intelligent and integrated manufacturing systems in order to meet the customer's demands and be the winners in the competitive market. Although, with available technologies and systems in Computer Integrated Manufacturing (CIM) and its related technologies, the application of CIM in manufacturing enterprises is a reality and can meet the need of the enterprises; today mangers in many enterprises are confused with varying technologies and new terminologies that prevail in the public domain. To make adoption and implementation issues complicated, there are many researchers pursing similar concepts but in different names to solve part of the issues that are or can be addressed by a CIM system. Therefore, this paper summarises the evolution of manufacturing technologies that are associated with developments towards a CIM system, and reviewed some of the new terminologies and technologies, which were proposed during the last four decades. This review is aimed at overcoming the confusion with the new terminologies that have been generated in the past four decades. Further, this paper articulates that all these new proposals are in deed the sub-system or sub-solutions of CIM. Finally, this article focuses on latest research developments in CIM and provides a stepwise justification methodology towards a CIM system for a small or a medium enterprise.     

Data fusion for adaptive control in manufacturing: Impact on engineering information models

Data fusion is the integration and analysis of data from multiple sensors to develop a more accurate understanding of a situation and determine how to respond to it. Although data fusion can be applied in many situations, this paper focuses on its application to manufacturing and how it changes some of the more traditional, less adaptive information models that support the design and manufacturing functions. The paper consists of four parts. The first section explains what data fusion is and its impact on manufacturing. The second section describes what an information system architecture is and explains the natural language-based information modeling methodology used by this research project. The third section identifies the major design and manufacturing functions, reviews the information models required to support them, and then shows how these models must be extended to support data fusion. The fourth section discusses the future directions of this work.     

Toward a cloud-based manufacturing execution system for distributed manufacturing

This paper illustrates the needs and challenges for the management of distributed manufacturing in a multi-company supply chain and processes these further as features of new IT systems. Requirements are collected from manufacturing companies and combined with insights from literature in the field of current ERP/MES system drawbacks, advantages, needs and challenges. The findings show that the needs and challenges in data integration inside SME networks are closely related to the limitations of current supply chain solutions. Current ERP-solutions lack extended enterprise support and a shared cloud-based approach. On the other hand, current MES solutions can operate the manufacturing process, but not for distributed manufacturing. As an answer to the requirements, we made a proposal for the core of architecture for next generation of MES solution in this position paper. Moreover, a pilot software tool has been developed to support the needs related to real time, cloud-based, light weight operation.     

AI tools for intelligent manufacturing

Conventional software tools are inappropriate for the representation of several important features of engineering knowledge. This paper outlines these features and discusses the applicability of several Artificial Intelligence techniques.     

Phase change fixturing for flexible manufacturing systems

Fixturing is fundamental to many manufacturing operations, hence, if computer integrated flexible manufacturing systems are to be truly flexible, then the fixturing must also be flexible. That is, it must be capable of accomodating parts of different geometries and sizes. This paper reports on an innovative class of flexible fixtures which utilizes materials that undergo a phase change between solid and liquid states. When in the liquid state, the fixturing medium can accommodate a wide variety of different part geometries, while in the solid state the part is held fixed. A mathematical model is developed which governs the holding ability of a particular class of these fixtures and some results of parametric computer studies are then presented.     

Recent trends in flexible automated manufacturing

In recent years, an important change in developing and implementing manufacturing systems can be observed in all industrialized countries. Due to intense international competition and the growth of personnel costs, companies are forced to use systems with a higher level of automation. At the same time, an increasing number of product variation—caused by adapting the products to customer requirements—demand more flexibility of machine tools and manufacturing systems.Basic types of computer-controlled flexible automated manufacturing systems will be shown and characterized by their special ranges of application. A planning procedure is presented which includes selecting a suitable systems structure such as; transfer line or flexible manufacturing system or automated manufacturing cell, and for determinating every single machine tool within the system. Examples of several new computer-controlled manufacturing systems which have been planned by the above planning procedure are presented with special regard to the evaluation of the system's economic performance.Finally, some rules are given for measuring the economic performance of automated manufacturing or assembly systems including automation of the handling functions.     

制造资源共享技术研究与实现

为了实现制造企业间的制造资源共享,提出了制造资源共享模型,在此基础上,分析了集中式、分布式及集中分布式制造资源共享体系结构,提出了以网络化制造平台、重点城市制造业信息化ASP平台和企业制造资源共享管理系统为主体的三级制造资源共享模式,开发了制造资源共享系统,介绍了该系统在四川省制造业信息化工程中的应用。