Computer Integrated Manufacturing Systems Research Articles

A computer integrated manufacturing system for rotational parts

In this paper, a computer integrated manufacturing system has been established. The integration of the CAD/ CAM/ CAPP is applied to smooth the design and manufacturing process of rotational parts. The CSG model is adopted to construct the solid geometry. The same part data is used in all of the CAD, CAM and CAPP modules. The basic primitives, such as the cylinder and the cone features, are used to build the main shape of the part. The manufacturing features, such as the groove and the thread, are attached to the corresponding primitives to modify the local shapes and add the high level manufacturing information effectively and efficiently. The smoothing operation of two adjacent primitives has been proposed to determine the correct dimensions of two connected primitives with tangential continuity. A feature recgonition algorithm has been proposed to convert the wire frame entities to CSG primitives. A GT code system and a process weighting method are proposed to recognize the part and generate the corresponding process plan. Algorithms for planning the cutter path and calculating the cutter locations have been proposed to generate the NC programme automatically. Cutting path simulation and cutting process animation are supplied in the proposed system to verify the CAM functions. Examples and the cutting experiment are given to demonstrate and verify the proposed CAD/ CAM/ CAPP integration system.

Economic view of CIM system architecture

The synergistic advantage of systems integration for Computer Integrated Manufacturing (CIM) has been a powerful thrust behind the productivity advancement in recent decades. However, the dependency among components, the intangible benefits and complexity of the system have been a barrier for system developers and the business community. This paper reports a systematic approach to assess economic merits of the CIM system. It projects CIM system designs on a multiple layer architecture with consideration of project life cycle. It introduces a modelling formalism to present a structured view of the economic aspect of the CIM system. The multiple criteria's aspect of CIM justification was treated with the AHP (Analytical Hierarchy Process) method. The complexity of various cost factors is reduced through application of the ABC (Activity Based Costing) method. The benefits of low level activities, both tangible and intangible, are then hierarchically aggregated into higher level system objectives. It also provides the necessary linkages between the economic and other views. A simple example was used to illustrate the approach.

CIM systems modelling for control system re-usability

The flexibility of computer integrated manufacturing (CIM) systems greatly depends on the performances of their control systems. Consequently, control systems design appears to be an essential phase in the overall design of a CIM system. However, a traditional design approach is no longer sufficient with regard to market reactivity. It seems necessary to make use of a generic control system that can be used in controlling a large set of manufacturing components and which may serve a wide range of manufacturing situations. This paper deals with an approach for the design of a flexible and reusable control system. These abilities are obtained by modelling, with a sufficient abstraction level, the invariant parts of manufacturing components and their interconnections. The approach has been applied in designing and implementing the control system of an actual flexible manufacturing cell.

Earliness/tardiness producution planning by JIT philosophy for job-lot manufacturing systems

In this paper, we study the problem of production planning for the typical job-lot manufacturing system. The production in this kind of manufacturing system has such features as global-market-oriented, one-of-a-kind production, differentiating products with high manufacturing cost, complicated structure and long manufacturing cycle time. Just-in-time production and delivery is the key element to be considered. Here, an earliness/tardiness production planning approach is proposed. It is compatible with the concept of JIT production and extends study of the single machine earliness/tardiness (E/ T) scheduling problem. An E/T production planning model is established which minimizes the earliness and tardiness penalties of all products under total production capacity constraint. The Lagrangian relaxation algorithm is developed to solve the model. To combine MRP-II with JIT philosophy, we have embedded the E/T planning approach into the master producproduction tion scheduling (MPS) or MRP-II, and have designed a hierarchical master production scheduling system. The E/T production planning approach and the designed MPS system are successfully applied to the computer integrated manufacturing system (CIMS) of the Shenyang Blower Plant in China, a typical one-of-a-kind manufacturing plant. Satisfactory results are reported.

Managerial Factors Critical To Cim Implementation

This study provides an empirical analysis of some managerial factors which are critical to the successful planning and implementation of Computer-Integrated Manufacturing (CIM) systems. CIM is viewed as an integrated computer-based information technology applications and as a strategic tool which ties together different technologies, as well as various functional areas and managerial levels. Thus, enough emphasis must be placed on communicating the company-wide goals and strategies to various functional areas and employees, particularly with regard to the CIM implementation. In this study, a number of managerial factors will be identified and factor analysis will be used to examine the technological and managerial factors.

Waiting line model applications in manufacturing

Improving manufacturing and attaining manufacturing excellence to gain competitive advantage has attracted a lot of attention in the last few years. Many manufacturing operations and many of the technological advances in manufacturing systems like FMS, AGVs, GT, CIM, cellular manufacturing, AS/RS and JIT production systems admit modelling via waiting line or queueing theory. In this paper, the literature available on the application of waiting line models in manufacturing is reviewed. Future research directions on waiting line model applications for improving the performance of the manufacturing are pointed out.

Petri net models for message manipulation and event monitoring in an FMS cell

A shop floor control system (SFCS), the central part of a computer integrated manufacturing system, performs the production activities required to fill orders received from the factory level control system. In order to effectively control these activities, a hierarchically decomposed SFCS (equipment, workstation, and shop) can be devised and implemented. The controller at each level is functionally decomposed into planner, scheduler, and executor which perform various tasks such as part dispatching, resource selection and assignment, message passing, event monitoring, communication, machine code downloading, etc. In particular, the executor is responsible for (1) monitoring and interpreting input messages, (2) making execution-based decisions, and (3) broadcasting messages and downloading machine instruction. The purpose of the paper is to present the interpreted Petri net models of the executors embedded in the workstation and equipment level controller. Each event is captured and processed and then some actions associated with the event are taken. These series of activities are modelled using interpreted Petri nets in which a circle node represents the set of actions (e.g. message sending, state variables and database updating, etc.), a bar node represents an event (e.g. message capturing), and an edge represents the transition between two nodes. The execution models have been implemented in an FMS cell with dumb planner and schedulers (meaning that planning and scheduling prblems are randomly solved). The form description of the executors presented in this paper will provide the shop floor control engineer with the basis of the rapid generation of shop floor control software. Since the Petri nets detect and process all the events, including even planning and scheduling events, an FMS cell can be intelligently controlled by plugging in a planner and scheduler into the Petri net models.

Quick-turnaround-time improvement for product development and transfer to mass production

We describe equipment and facility operational methods in a production fab which are designed to achieve quick-turnaround-time (QTAT) manufacturing and ease product transfer from development to mass production. An advanced CIM system with precise lot management is introduced to keep the optimum balance of manufacturing TAT and throughput. Substantial end-user computing reduces the engineering holding time for handling development lots. In situ monitoring technologies are applied for the utilization enhancement of plasma-assisted equipment. A 9% manufacturing TAT reduction and a 14% throughput increase are estimated using a manufacturing simulator. The number of wafers in QTAT lots is reduced for processing time reduction. As a result, manufacturing TAT of QTAT lots with reduction from 24 wafers to three is reduced to 56% compared with that of normal lots in the production fab. This new production fab realizes QTAT development and agile product transfer from development to mass production with full process compatibility.

The role of models in future enterprises

This paper describes the general problem of manufacturing, discusses the impact and consequences of the growing internationalisation of markets and gives an overview of the trends in key technologies of manufacturing systems. Furthermore, the need for models to support the design and reorganisation of CIM systems and Virtual Factories is discussed. Finally, particular approaches to solve such problems are introduced.

Extraction of manufacturing features from a feature-based design model

With the thriving advancement of computer-integrated manufacturing systems, a further elevation of process-planning automation has become a must. In order to target automated process planning, one has to gain more understanding on how the manufacturing information can be obtained directly from parts' CAD models. In essence, a computer-aided process planning system uses 'manufacturing features' to generate information about machining operations for a part. The information from manufacturing features, however, is not explicitly embedded in traditional CAD systems. Therefore, one resorts to a certain method which leads to manufacturing features by analysing and reasoning part geometry. In regard to the above issue, there are two primary approaches found in literature, namely design by features and feature recognition. This paper attempts to integrate these two approaches to accomplish automatic extraction of manufacturing features from a design-oriented feature model. Pro/ENGINEER, a commercial feature-based CAD package, is used in this research as the source of part models. The solid geometry together with the data of design features are extracted through the use of Pro/DEVELOP, a system development tool of Pro/ENGINEER. The extracted feature data is then analysed respectively by face re-organization, feature recognition, and feature concatenation algorithms. The final results are a set of manufacturing features which can be used, directly or indirectly, in the downstream manufacturing activities, including process planning, NC cutter path generation, and operation scheduling.

Integrated application in CAD/CAM, scheduling and control

Integrates CAD/CAM, production control and process control in a case study involving manufacturing automation. The manufacturing firm is a distributed cellular system operating in a produce‐to‐order environment. Combines a parametric CAD software with global variables and global relations to achieve a design automation. Results obtained from design automation are transmitted to update the design model and the associative manufacturing model. In addition, scheduling and control are also integrated in the system. Distinguishes three scheduling levels: static scheduling, rescheduling, and real‐time scheduling. For a distributed and effective reason, the distributed shifting bottleneck procedure (DSBP) is adopted as the static scheduler and rescheduler, and the LRPT (longest bottleneck processing time) despatching rule is adopted as the real time despatching rule. FInally, introduces the configuration of the system including the flexible manufacturing cell architecture and the input buffer device. Uses a PLC programming toll that follows the IEC 1131‐3 standard to implement cell controllers. The above implementation aims to easily and effectively execute the CIM system.

Constraint maintenance in engineering design system: An active object-oriented approach

This paper proposes a framework of engineering constraint maintenance using an active object-oriented database and solves a problem encountered when implementing the framework. The framework is proposed for the information-driven CIM system that integrates engineering constraints as well as its data. It resolves problems of the existing application-oriented constraint maintenance in which constraints are scattered in heterogeneous applications. It is possible due to the integrated management of constraints on a database using triggers, that is, on an “active” database. Existing active object-oriented databases, however, cannot properly support certain constraints that are specified on a set of classes. Those are the cases where the constraints must be maintained in the forward direction along a class composition hierarchy as well as in the backward direction. We call these kinds of problems “backward propagation problems” and investigate several approaches to resolve them using currently available techniques. Based on an approach which uses virtual classes, a new constructor, called CONSTRAINT CCH is proposed to support the backward propagation. Advantages of the proposed framework and the constructor for the backward propagation are demonstrated on a design constraint management that supports a control panel design.

White balance in inspection systems with a neural network : Yamashina, H.; Fukushima, K.; Kano, H. Computer Integrated Manufacturing Systems, Vol. 9, No. 1, pp. 3–8 (1996)

White balance in inspection systems with a neural network : Yamashina, H.; Fukushima, K.; Kano, H. Computer Integrated Manufacturing Systems, Vol. 9, No. 1, pp. 3–8 (1996)

Adaptive welding for shipyards

Reports on an aggressive project to develop an advanced, automated welding system, being completed at Babcock & Wilcox, CIM Systems. This system, the programmable automated welding system (PAWS), involves the integration of both planning and control technologies to address the needs of small batch robotic welding operations. PAWS is specifically designed to provide an automated means of planning, controlling, and evaluating critical welding situations in shipyard environments to improve productivity and quality. Five varieties (wall, lathe, floor mount, cantilevered, and gantry) of PAWS welding systems currently exist.

Analysis of computer integrated manufacturing systems by fuzzy human operator behaviour

Analyses computer integrated manufacturing systems with the real‐time constraints under the condition that time to repair depends on human experience and can be fuzzy. Proposes an approach which combines probability and possibility measures. Illustrates the impact of the growth of human experience on the reliability characteristics with an application example.

Improving the PAC shop-floor control architecture to better support implementation

Development of shop-floor control (SFC) systems is a very complex task. Not only are such systems inherently complex, but their development also requires skills from several different fields. The lack of a common overview of SFC systems often results in hard-coded SFC systems that have little of the flexibility one might expect from a CIM system. To help developers of automated manufacturing systems to better structure their design, and thus improve the implementation of the SFC system, an SFC architecture could be used. It enables developers to structure their problems and to discuss them using a common language. In this paper, parts of the COSIMA (COntrol Systems for Integrated MAnufacturing) SFC architecture are analysed and improvements to better support implementations are suggested. This paper shows that although the COSIMA production activity control (PAC) provides a sound basis for an SFC cell-level architecture it has its shortcomings. Its weaknesses are mainly twofold: its granularity at the work-station level is too coarse and its information-flow handling is too centralised. By splitting the mover and producer into several such entities, each corresponding to a work-station in the cell, and moving parts of the information-handling from the monitor to these new entities, both problems can be solved.

Improving Manufacturing Efficiency with Business Intelligence Software

Abstract Many Slovene manufacturers face increasing competition which demands continuous improvement in products and productivity. The well-known methodology of Computer Integrated Manufacturing (CIM) allows manufacturing conlpanies to remain competitive. Effective CIM systems require integrated information systems along with Business Intelligence Software (BIS) to support organizational decision-making. This paper proposes a comprehensive conceptual framework with corresponding guidelines required for a successful application of BIS to improve operations and capabilities. Typical examples of business problems that can be solved by linear programs using a newly developed graphical human-machine interface are shown.

An information system for computer-integrated manufacturing systems

One of the main problems when implementing the computer-integrated manufacturing (CIM) concept concerns information integration. In order to support information integration, an information system provided with suitable data models is required. In this paper an information system is presented, which fulfils the requirements for an appropriate information management in CIM. For this purpose, an EXPRESS-oriented information system has been built on top of a commercial relational DBMS. The conceptual model of the information is built in EXPRESS and then parsed and translated to the corresponding relational constructs. A data access interface has been implemented which allows EXPRESS-oriented data manipulation. The information system was developed inside ESPRIT project No. 2202 CIM-PLATO “CIM System Planning Toolbox” to integrate the information used by the tools developed for flexible manufacturing system planning.

Design of a simulation library for CIM

It is now feasible to include simulations in CIM systems, where the simulation is but one component which should be fully integrated with the other parts to support real-time decisions. We show how to formulate specifications for a simulation software to optimally serve CIM systems and how to translate specifications to a working code which has been successfully utilized in numerous applications. Its claimed suitability to CIM is presently under test.

Application of Artificial Reality in Manufacturing Industry

The role of human beings to the computer integrated manufacturing system is to be re-evaluated from the point of view of flexible and agile manufacturing. This paper deals with this issue from the stand point of the smooth communication between human beings and computers with models and images of products and factories in it, and discusses the effectiveness of 3-dimensional models and images with artificial reality for industrial product design and production. It also develops the possibility of the virtual factory with artificial reality and classifies the virtual factory from the view of the concerning styles of human beings to the factory system. This paper unifies human beings and sense-of-presence devices to H, computer and communication to C, and real (physical) objects and world to R, and discusses the four combining types of the virtual factory.