摘要:

This paper indicates the need for studying the effect of informational loads on performance times of manual components of combined manual and decision (Type II) tasks before a valid cycle-time prediction methodology for such tasks can be developed. Findings of a 2 × 3 completely randomized factorial experiment, in which ten subjects were used, are presented. For this study element reach of throe different magnitudes, i.e. 7 inches, 10 inches and 14 inches and three levels of informational load, i.e. 1 bit, 2 bits and 3 bits were used. Results indicate that increase in performance time due to informational load is highest for reach of the smallest magnitude and it decreases as magnitude of reach increases. For the same magnitude of reach performance time increases as informational load.

ISSN:0020-7543    

DOI:10.1080/00207547408919547

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

The paper starts by introducing and discussing the results of wide-ranging field sudies carried out within manufacturing industry with the purpose of determining how accurately important engineering parameters with respect to processing materials are identified in practice. The results show exceptionally wide variations even in comparison with the recommended limits of a data bank. The paper infers the difficulties for proper assessment of advanced technology given that conventional technology is not yet adequately understood under operating conditions.

ISSN:0020-7543    

DOI:10.1080/00207547408919548

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

The contents of this paper show that when a metal toreion specimen is subjected to an axially applied compressive stress, then the resulting angle of twist recorded up to fracture will be greater than if tested under plain torsion conditions. Increasing this longitudinal compression results in a further increase in the fracture strain.

ISSN:0020-7543    

DOI:10.1080/00207547408919549

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

An analysis of the process : Indentation of a cone into a semi-infinite material has until now only been made in cases of no friction between tool and specimen. By means of the axi-symmetric upper bound theory, it is shown how p/k can be determined for indentation into a prepared cavity with friction taken into consideration. Analysis has been made for the oone-angles 10°; 20°; 30°; ⃛; 170°; 179·8°; and the friction factors 0; 0·2; 0·4; ⃛ 1·0. The velocity fields and pjk values found, correspond well to those in earlier literature concerning the axi-symmetric slip-line theory. On the basis of the theoretical results, the friction factor causing change from Hill's to Prandtl's slipline field for the plane strain analogy is determined as a function of the semi-angle of the tool. Furthermore curves of the average effective strain in the deformation zone are determined theoretically as a function of cone-angle and friction factor.

ISSN:0020-7543    

DOI:10.1080/00207547408919550

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

The use of part family or group technology methods for machining operations is well established and several manufacturing systems baaed on this approach are in existence, as well as rationalized and automated procedures for design, process planning, etc. It is less well recognized that a similar approach to metal forming operations can lead to substantial benefits also. In this paper the possibilities for extending this approach to bulk metal forming operations (forging, stamping, etc.)are outlined. In particular systematic procedures for component and die design are described based on classification and coding systems for formed parts. In this context, the selection of forging features (draft, allowances, etc.), billet size estimation, and so on are considered.

ISSN:0020-7543    

DOI:10.1080/00207547408919551

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

A finish turning case is presented where an increase in tool Life was obtained without sacrificing surface finish. This was obtained by developing mathematical models for tool life and surface roughness in terms of the cutting speed, feed and depth of cut. Their contours were obtained utilizing PL 1 language and an IBM 360/50 computer, then the contours were superimposed in order to select the proper combination of cutting conditions.

ISSN:0020-7543    

DOI:10.1080/00207547408919552

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

The paper reviews problems encountered when using overhung boring bars fitted with single point tooling for profile boring operations. Above certain length to diameter ratios, which are affected by the diameter of the bars and the base fixing conditions, the stiffness is inadequate permitting the build-up of unstable vibrations and making it difficult to maintain accuracy of the form of the bore.

ISSN:0020-7543    

DOI:10.1080/00207547408919553

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

An exploratory model for cutting is presented which incorporates fracture toughness as well as the commonly considered effects of plasticity and friction. The periodic load fluctuations Been in cutting force dynamometer tests are predicted, and considerations of chatter and surface finish follow. A non-dimensional group is put forward to classify different regimes of material response to machining. It leads to tentative explanations for the difficulties of cutting materials such as ceramics and brittlo polymers, and also relates to the formation of discontinuous chips. Experiments on a range of solids with widely varying toughness/strength ratios generally agree with the analysis.

ISSN:0020-7543    

DOI:10.1080/00207547408919554

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

A method of problem expansion is shown to increase the solution speed for a class of zero-one programming problems, especially when Lagiange multipliers are used to incorporate constraints into the problem objective function.

ISSN:0020-7543    

DOI:10.1080/00207547408919555

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

This paper eals with the dynamics of a computer-based inventory control system. In general Buch a real-life system is designed according to the most basic principles of static inventory theory. To control the system in a dynamic sense, management has to vary the policy parameters of the system. Two different mathematical models of inventory dynamics are introduced. The first ie a simple first-order differential equation and the second a discrete multidimensional model. Applications of the two models are discussed with the aid of examples concerning, on the one hand, changes in policy parameters, and on the other production smoothing.

ISSN:0020-7543    

DOI:10.1080/00207547408919556

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor