CIM includes the experimental shop

Integration of computers in the manufacturing process has rightfully emphasized their use in electronically conveying complex product geometry from engineering design and drafting to the design of manufacturing fixtures and part programming. The relative absence of literature and software relating to the use of micro-computers in the experimental (prototype) shop suggests that at best, their usage is limited and at worst, not amenable to very small lost size production quantitities.Experience with a trial program suggests the contrary. While the project described in this paper is far from a full implementation, early results suggests that micro-computers can be effectively used to:

• 1.(1) Improve communications between the designer and the shop.
• 2.(2) Assist the shop in purchasing, process planning the control of spare prt inventories.

Also included in the paper is an overview of the software as contrasted with conversion high volume production planning and inventory control systems to emphasize the fundamental differences in functional usage. The paper concludes with a discusson of future extensions to provide networking and graphic capabilities that shows promise of improving the feedback loop to engineering design and manufacturing.     

BCL and CIM

The paper outlines the new EIA RS-494 standard, “32 Bit Binary CL exchange (BCL) input format for numerically controlled machines” and its impact on computer integrated manufacturing (CIM). The advantages and disadvantages of BCL in a CIM environment are discussed at length.     

Factory environment and CIM

This contribution on the topic of factory environment and CIM is divided into two parts. The first part deals with some fundamental aspects of intelligent manufacturing systems for the new generation factories. This subject is divided into three blocks: intelligent manufacturing systems, expert systems and intelligent CAE/CAD/CAM. Based on the input-output approach, some basic requirements for IMS definition are given.

The second part deals with the problem of the factory environment and CIM, more specifically from historical aspects to the contemporary factory and some conceptual designs aspects of FMS. At the end, an example of structural pattern recognition of FMS is given.     

流程CIM与离散CIM之比较

本文首先从物流、工艺和生产控制自动化等方面分析了流程生产的特点并与离散制造进行了比较。研究了流程ＣＩＭ的体系结构、系统构成，指出流程ＣＩＭＳ通常只包括生产实施（过程控制）与管理信息两个应用系统。过程控制在流程ＣＩＭＳ中占有特殊重要地位。集散控制系统是过程控制与信息集成的基础。     

Latest developments in CIM

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 today's 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.     

Process Planning System in the CIM Environment

This paper describes an approach to the integration of Process Planning with Computer Aided Design and Computer Aided Manufacturing functions. The link is established through IGES which is used to transfer the geometric data from the CAD system to the process planning system. The process planning system can subsequently use this data in generating a detailed process plan as well as an NC part program for the manufacture of the part and can therefore be used as the basis of true integration between CAD and CAM.     

Achieving CIM Through Mastery of the Basics

Many manufacturers are considering computer-integrated manufacturing in their search for a competitive edge. However, before automating inefficient processes, companies should first examine and streamline their current methods of operation.     

Scheduling a dynamic job shop production system with sequence-dependent setups: An experimental study

This paper presents the salient aspects of a simulation-based experimental study of scheduling rules for scheduling a dynamic job shop in which the setup times are sequence dependent. A discrete event simulation model of the job shop system is developed for the purpose of experimentation. Seven scheduling rules from the literature are incorporated in the simulation model. Five new setup-oriented scheduling rules are proposed and implemented. Simulation experiments have been conducted under various experimental conditions characterized by factors such as shop load, setup time ratios and due date tightness. The results indicate that setup-oriented rules provide better performance than ordinary rules. The difference in performance between these two groups of rules increases with increase in shop load and setup time ratio. One of the proposed rules performs better for mean flow time and mean tardiness measures.     

CIM system for telecommunications equipment

Much of telecommunications equipment manufacturing consists of relatively small production runs of a wide variety of products. This paper discusses the problems in such manufacturing systems and the development of a computer-integrated manufacturing system proposed to solve these problems.     

BARRIERS TO EFFECTIVE CIM IMPLEMENTATION

Despite the potential of computer-integrated manufacturing (CIM) to improve quality and productivity while reducing costs, successful implementations are more the exception than the rule. This article reviews the success stories, the barriers that trip up companies that fail, and the role of IS in helping companies to avoid them.     

Flow shop vs. permutation shop with time delays

This paper considers the evaluation of the worst-case performance ratio between the best solution of the flow shop problem and the permutation flow shop with time delays considerations. It is observed that, even in the restricted case of two machines and unit execution time operations, the two models may generate different optimal values for the makespan. More specifically, it is shown that, in the two-machine case, the performance ratio between the best permutation schedule and the best flow shop schedule is bounded by 2. When the operations of the n jobs are restricted to be unit execution time, this ratio is reduced to (2−(3/n+2)) for the two-machine case, and is m for the m-machine case.     

Solving job shop scheduling with setup times through constraint-based iterative sampling: an experimental analysis

This paper presents a heuristic algorithm for solving a job-shop scheduling problem with sequence dependent setup times and min/max separation constraints among the activities (SDST-JSSP/max). The algorithm relies on a core constraint-based search procedure, which generates consistent orderings of activities that require the same resource by incrementally imposing precedence constraints on a temporally feasible solution. Key to the effectiveness of the search procedure is a conflict sampling method biased toward selection of most critical conflicts and coupled with a non-deterministic choice heuristic to guide the base conflict resolution process. This constraint-based search is then embedded within a larger iterative-sampling search framework to broaden search space coverage and promote solution optimization. The efficacy of the overall heuristic algorithm is demonstrated empirically both on a set of previously studied job-shop scheduling benchmark problems with sequence dependent setup times and by introducing a new benchmark with setups and generalized precedence constraints.     

CIM逻辑模型的关系实现

针对逻辑模型在查询和存储方面的不足,定义与其具有一致表示能力的关系模型,并将逻辑模型中以句子形式表示的逻辑约束转化为针对关系模型中逻辑关系的势的约束。根据模型的访问,以IEC61970所采用的数据访问接口DAF为例,在上述关系模型中给出基于关系代数的实现。研究结果表明,通过选择合理的关系模型,可以在保持逻辑模型丰富的表达能力的基础上,利用关系代数提高模型访问的效率,同时保证约束判定的有效性。