摘要:

Tolerance can be viewed as the allowable range for a dimension in order to satisfy product functionality requirements. Compliance of machined parts to tolerance specifications is necessary if a manufactured product is to have good fit and desired functional characteristics. We present a method for assessing compliance of several cylindrical part features based on comparing tolerance specifications with actual measurement data. A single measure of compliance is developed based on the alignment of individual part features. A part with multiple holes is used to illustrate the approach.

ISSN:0740-817X    

DOI:10.1080/07408179408966580

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

In this paper, we present the concepts behind die implementation of behavioral and cognitive capabilities in objects used for controlling workstations in manufacturing systems. These capabilities characterize a new class of objects called agents; such objects intuitively play die role of human decision-makers in the system modeled. Three types of reasoning activities are considered: a meta-reasoning level to control the inference/search reasoning activities, die local reasoning level incorporating simple rule-based procedures and an extended reasoning level representing the reasoning activities that cannot be performed using simple procedures and thus require external knowledge agents to assist the decision-making process. Implementation issues are discussed, illustrated by an application of the approach to the modeling of workstations in a rolling-mill facility.

ISSN:0740-817X    

DOI:10.1080/07408179408966581

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Strip layout is an important step in the planning of operations using blanking dies. Typically the strip layout problem has been resolved using methods which provide approximate solutions, since it is viewed as a class of general 2-D nesting problem which is NP-Hard. This implies that we need to investigate special cases of the strip layout problem that will permit polynomial running time algorithms, while having some practical application in processes of cutting shapes from sheet stock. In this paper we present an exact procedure with polynomial running time for die single-pass single-row layout problem. This problem tries to layout identical shapes on a strip that will go thorough a single row die only once, such as to maximize die number of parts to be yielded by the strip. The paper investigates this problem for two cases: the case for which die width of die strip is larger than any possible orientation of the part, and the case for which the width of die strip is restricted so mat not every orientation is feasible. We also consider the problem of cutting a sheet of metal into strips so as to maximize die sum of me parts yielded by each sheet.

ISSN:0740-817X    

DOI:10.1080/07408179408966582

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

In this paper, we develop procedures for dividing rectangular warehouses into classes. We describe three types of classes and develop their corresponding traveling time models. A solution procedure involving a one-dimensional (or at most two-dimensional) search is developed. We show that the one-dimensional search procedure is very effective in solving most practical problems. Additionally, we show that most of the savings obtained by a full-turnover policy can be obtained with a relatively few classes—a result similar to the one obtained for the square AS/RS.

ISSN:0740-817X    

DOI:10.1080/07408179408966583

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

We model the repetitive placement by a Cartesian robot of n parts on a rectangular workpiece. There are n bins or feeders (one per part), to be placed around the boundary of the workpiece, which contain the parts. The robot picks a part from a bin, places it, picks another part, places it, etc.; any placement sequence is possible. The problem, to find bin locations and a placement sequence to minimize total assembly time, is formulated as a traveling salesman problem (on a graph withnnodes) with special structure. This structure allows the computation of a lower bound on the minimum total assembly time in orderneffort. The lower bound improves as n increases, and leads to a simple solution algorithm which gives asymptotically optimal solutions in ordern log neffort. For die case where parts are uniformly distributed on the workpiece, we give simple closed-form expressions for the expected value of the lower bound. These expressions should be helpful for design decisions; for example, holding n constant, they indicate that square workpieces require more assembly time than non-square, rectangular workpieces of the same area. Most of our results are relatively insensitive to the inclusion of robot acceleration/deceleration effects.

ISSN:0740-817X    

DOI:10.1080/07408179408966584

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The visual inspection of parts as they progress through die manufacturing process is an important task in all industries. Visual inspection, when performed by humans is a tedious task and is prone to error. This is precisely what makes it a good candidate for automation. Although computer vision systems have been around for over 30 years, die industrial applications of vision systems have become practical only in die last decade. Image processing and pattern recognition algorithms used in industrial vision systems are built upon a broad body of knowledge in vision research. But the use of computer vision systems in quality control has been limited to replicating die visual inspection tasks as they would be performed by a human operator. It is die contention of this study that when computerized inspection is employed, quality control inspection plans suitable for computerized inspection should also be employed to assure cost-effectiveness.

ISSN:0740-817X    

DOI:10.1080/07408179408966585

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

In this paper we present a general-purpose analytical model to compute die approximate throughput capacity of a trip-based material handling system used in a manufacturing setting. A wide variety of handling systems, including freight elevators, cranes, microload automated storage/retrieval (AS/R) systems, industrial lift trucks, and automated guided vehicle (AGV) systems can be modeled as trip-based handling systems. To our knowledge, this model is one of the few analytical models that explicitly considers an empty device dispatching rule. The model is first developed for a single-device system (such as a crane) and subsequently, with a simple modification, it is extended to multiple-device systems (such as lift trucks and AGVs). Using this model one can rapidly evaluate a wide range of handling and layout alternatives for given flow data. Hence, die model would be most effective when used early in the design phase to narrow down die set of alternative handling systems and configurations prior to simulation.

ISSN:0740-817X    

DOI:10.1080/07408179408966586

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Maximizing the throughput (or revenue generation) rate has become one of die most important criteria in die design and management of Flexible Manufacturing Systems (FMSs). This paper develops dynamic part-allocation policies for FMSs having finite storage capacity at each work station. Maximizing the throughput rate means that the resulting queueing network model has a state-dependent arrival process; therefore, product-form solutions do not hold. Consequently, several alternative modeling approaches are described and formulated for deriving die optimal part-routing policies. One of these optimal policies is based on a new initiated-suspension part-routing strategy. This strategy results in a reduced load on the material handling system while increasing die expected throughput (or revenue generation) rates of the manufacturing work stations. We also propose several efficient closed-loop heuristic policies that exploit die response structure of die optimal policies. These heuristic policies are of practical significance because they are extremely easy to compute and to implement, while die resulting FMS performance is nearly optimal.

ISSN:0740-817X    

DOI:10.1080/07408179408966587

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The order picking function in a warehouse involves selection of items from storage areas in order to satisfy customer demand. It has been identified as the most costly warehouse operations activity. Cluster analysis identifies groups of items that are frequently ordered together. Items within a cluster may be located near one another, and efficient picking tours may, thus, be formed. We formulate the clustering problem as ap-median 0-1 integer program which may efficiently be solved to optimality.

ISSN:0740-817X    

DOI:10.1080/07408179408966588

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

ISSN:0740-817X    

DOI:10.1080/07408179408966589

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor