Automatic Transfer Lines Research Articles

О производительной силе и производительности труда (вопросы теории и практики)

the authors consider two intermediaries: the intermediary between the world of the nature and the person – means of work or "fixed capital" of a society as productive force of social activities, and the intermediary inside a society – cost in the form of money without what it is impossible to define labour productivity and structural transformations in a society. The article gives engineering understanding of productive force and productivity of the process equipment by the example of calculation and a choice of the automatic transfer line.

INFLUENCE OF PARAMETERS OF THE CALIBRATION PROCESS ON BENDING STIFFNESS OF STEEL ROD

The calibrated metal is efficient material for manufacture of details on automatic machines and automatic transfer lines, and also for production of smooth lengthy shafts and axes. Such details are not technological as during the machining and operation they change a form in a type of a curvature. Deformation comes at action of centrifugal forces even from sole weight of details. New constructional materials allow to create rather strong details with the reduced transverse section, but a flexural rigidity of such details significantly decreases. It is very difficult to increase flexural rigidity of actual details. In practice, constructive solutions that are associated with material costs are usually used. In this work the possibility of increase in a flexural rigidity of the cylindrical calibrated bars is considered due to the formation of technological residual stresses. The problem of their use is that residual stresses always exist of two types – stretching and squeezing. If external stresses of stretching increase rigidity of details, then pressure loads reduce it. Therefore, the main task of the work was to find such nature of distribution of residual stresses which would provide increase in a flexural rigidity of the details made of calibrated metal. The geometrical model of a bar consisting of thin-walled tubes of 0.2 mm thick was accepted at model operation of residual stresses. Each tube was loaded with the stretching or squeezing tension which corresponded to value of the experimental definition. At model operation and calculation two schemes of loading were used at which in the surface layers either residual stresses of compression or stretching are formed. Experimental calculation methods established influence of key parameters of calibration on a flexural rigidity of metal. The possibility of increase in a flexural rigidity of the calibrated bars is revealed almost twice when cogging from 5 to 34 %. For 20 % it is possible to increase rigidity at increase in length of the calibrating zone of the tool. The influence of the angle of the working cone of the machine is insignificant (about 10%), and for increasing the rigidity the operating angle of the tool must be reduced.

プロセスの順序性に着目した事象駆動型システムの確率的故障診断

This paper presents a fault diagnose method for event-driven systems based on probabilistic inference, Timed Markov Model (TMM). The TMM is one of semi-Markov process models wherein state transition probabilities depend on stay time at a state. The TMM requires numerous amount of learning data to establish a diagnosis system, and it is difficult to collect enough learning data in a large and complex system. This paper focuses on a diagnosis strategy based on sequential order of processes in the event-driven system, and the method can diagnose the fault even if the amount of learning data is not rich. Finally, the usefulness of the proposed strategy is verified through some experimental results of an automatic transfer line.

Factory Tour of Mimaki Engineering Co. Ltd.

Mimaki Engineering Co. Ltd., founded in the city of Tomi, Nagano Prefecture in 1975 and listed on the JASDAQ Stock Exchange in 2007, is an up-and-coming company. At first, the company developed and manufactured the special order item like the electrical equipment unit, the chip mounter, and the automatic transfer line system, etc., which were the “Engineering” still remaining in the name of the company. The Company’s first ever original product was a pen plotter which made the best use of the servo technologies cultivated in earlier experiences in producing custom-made products. This then led to the development of cutting plotters that utilize cutters instead of pens. Knowledge gained on the needs and characteristics of the Company’s mainstay market seems to have opened the door to the later commercial success of the company. The product that has most influenced the direction of the company has been the large-size ink jet printer put on the market in 1996. The company, in order to meet the needs of sign graphics (the company’s mainstay market), has added new inks and technologies for large-sized printing to the fundamental ink jet technologies introduced by Epson, and in so doing has grown into a leading company in the field. Moreover, the Company has steadily prepared to advance into the field of industrial products with printing and cutting technologies applied to plastic plates, etc. and also into the textile and apparel field, in which printing is done on fabric. These technologies all provide main stay products for digital on-demand production, an innovative production method.

Optimisation of multi-position machines and transfer lines

A new optimisation problem for design of multi-position machines and automatic transfer lines is considered. To reduce the number of pieces of equipment, machining operations are grouped into blocks. The operations of the same block are performed simultaneously by one piece of equipment (multi-spindle head). At the studied design stage, constraints related to the design of blocks and workstations, as well as precedence constraints for operations are known. The problem consists in an optimal grouping of the operations into blocks minimizing the total number of blocks and workstations while reaching a given cycle time (productivity). A constrained shortest path algorithm is developed and tested.

On-Line Fault Inference for Large-Scale Event-Driven Systems based on Bayesian Network and Timed Markov Model

Abstract This paper presents an on-line fault inference, diagnosis, and detection strategy for large-scale event-driven controlled systems. First of all, the controlled plant is decomposed into some subsystems, and the global diagnosis is formulated using the Bayesian Network (BN), which represents the causal relationship between the fault and observation in subsystems. The graph structure of the BN is constructed based on the control law adopted in the system. Second, the local diagnoser is developed using the conventional Timed Markov Model, and the local diagnosis results are used to specify the conditional probability assigned to each arc in the BN. By exploiting this decentralized architecture, the computational burden for the diagnosis can be distributed in the subsystems. As the result, the diagnosis for large scale practical system can be realized on-line. Finally, the usefulness of the proposed strategy is verified through some experimental results of an automatic transfer line.

Performance Evaluation of an Automatic Transfer Line with WIP Scrapping During Long Failures

We develop a model of a failure-prone, bufferless, paced, automatic transfer line in which material flows through a number of workstations in series, receiving continuous processing along each workstation. When a workstation fails, it stops operating, and so do all the other workstations upstream of it. The quality of the material trapped in the stopped workstations deteriorates with time. If this material remains immobilized beyond a certain critical time, its quality becomes unacceptable and it must be scrapped. We develop analytical expressions for important system performance measures for two cases. In the first case, the in-process material has no memory of the quality deterioration that it experienced during previous stoppages, whereas in the second case it has. In both cases, we assume that the workstation uptimes and downtimes follow memoryless distributions. We use the analytical expressions to numerically study the effect of system parameters on system performance. To evaluate the memoryless assumption, we compare the performance of the original model to that of a modified model in which the workstation downtimes do not follow memoryless distributions. The performance of the modified model is obtained via simulation.

2P1-A01 Bayesian Networkを用いた事象駆動型システムの故障診断(動作計画と制御の新展開)

This paper presents a new fault diagnosis strategy for the event-driven controlled systems such as Programmable Logic Controller. First, the controlled plant is considered to be divided into some subsystems and the time interval between succesive two events in each subsystem is modeled as a randam variable. Then, the fault diagnosis algorithm is proposed by using the Bayesian Network (BN), which can represent the causal relationship between subsystems. Furthermore, the design algorithm for the structure of the BN is developed using the information on the control law and the controlled plant. As a result, large scale diagnosis problem can be addressed with less computational burden. Finally, the usefulness of the proposed strategy is verified through some experimental results of an automatic transfer line.

OPTIMAL DESIGN OF TRANSFER LINES WITH BLOCKS OF PARALLEL OPERATIONS

This paper is devoted to a preliminary design problem of paced automatic transfer lines. The aim is to choose a logical layout of the line which minimises its cost subject to the given productivity and technological constraints. The paper focuses on a mathematical model of the problem and a method to solve it. The proposed method is based on the transformation of the initial problem into a constrained shortest path problem.

Industrial Use of Plasma-Emitter Electron Sources

This paper presents a description of plasma-emitter electron sources and their principle of operation, design, and performance. The experience gained in operating electron sources of this type as units of automatic transfer lines for electron-beam welding is described. The use of these devices for electron-beam fusing of composite powdered materials is also discussed.

Decomposition Methods to Optimise Transfer Line with Parallel and Sequential Machining

This paper is devoted to a preliminary design problem of synchronised automatic transfer lines. The aim is to minimise the line life cycle cost per piece under the given productivity and technological constraints. The paper focuses on a mathematical model of the problem and methods to solve it. The model is formulated in terms of mixed (discrete and non-linear) programming. For solving the optimisation problem, a special decomposition scheme is proposed, which is based on parametric decomposition technique.

Optimal design of a class of transfer lines with blocks of parallel operations

A problem of optimal design of automatic transfer lines is considered. For these lines, operations are partitioned into blocks. The operations of the same block are performed simultaneously, and different blocks of the same workstation are executed sequentially. The relations of the necessity and the possibility of combining operations in blocks and workstations as well as precedence constraints are given. The problem is to minimize the total number of workstations and blocks, providing a given cycle time and satisfying the above constraints. Two methods are proposed to solve the problem. The first one uses mixed integer programming, the second is based on reducing the initial problem to the shortest constraint path problem.

資源・素材技術の最近の進歩 亜鉛電解工程における陰極板自動搬送システムの導入について

資源・素材技術の最近の進歩 亜鉛電解工程における陰極板自動搬送システムの導入について

Petri net models of flexible and automated manufacturing systems: a survey

Petri nets (PNs) have recently emerged as a promising approach for modelling flexible and automated manufacturing systems. PNs are a graphical and mathematical modelling technique that is useful for modelling concurrent, asynchronous, distributed, parallel, nondeterministic, and stochastic systems, as attested by a steady stream of papers which appeared throughout the 1980s. Since 1989, there has been an explosion of interest in using PNs to model, simulate, and analyse manufacturing systems. We present an overview of PN theory. We then present a schema for categorizing PN models of manufacturing systems, followed by a survey of PN models of flow lines, automatic transfer lines, job shops, flexible manufacturing systems, and assembly systems. This discussion represents the most comprehensive survey of applications of PNs to manufacturing through 1994. Finally, we present a summary and some conclusions.

Simulation of automated manufacturing systems

The development of the general theory of automated manufacturing systems (AMSs) which involve automatic transfer lines, comprehensively mechanized lines, robotic systems, flexible manufacturing systems, integrated systems gives rise to objective necessily to simulate its structure, functioning, dynamics, reliability and stability of operation, production of some amount of goods, stay time of products and so on. As far as time and space are concerned, functioning of AMS is approximately represented by Markovian chains. Various urgent aspects of operation of some AMSs are represented in original and fundamental works by Little, Koenigsberg, Hatcher, Hiller and others. Alongside it, the development of the general theory of AMS is very important, because representation of structure and operation of AMS in the form of mathematical models is necessary for its realization. While carrying out synthesis and analysis of AMS's structure construction of mathematical models is also necessary. In this paper the algorithm of forming is given and the most general and informationally widened topological and mathematical models of open, closed and mixed AMSs in the form of three-dimensional node graphs, binary sets, mutual relations, numerical sequences, degree polynomials, different matrices and collections of algebraic equations are constructed. Fields of models' practical application are given.

Discrete storage processes and their Poisson flow and fluid flow approximations

Consider discrete storage processes that are modulated by environmental processes. Environmental processes cause interruptions in the input and/or output processes of the discrete storage processes. Due to the difficulties encountered in the exact analysis of such discrete storage systems, often Poisson flow and/or fluid flow models with the same modulating environmental processes are proposed as approximations for these systems. The analysis of Poisson flow and fluid flow models is much easier than that of the discrete storage processes. In this paper we give sufficient conditions under which the content of the discrete storage processes can be bounded by the Poisson flow and the fluid flow models. For example, we show that Poisson flow models and the fluid flow models developed by Kosten (and by Anick, Mitra and Sondhi) can be used to bound the performance of infinite (finite) source packetized voice/data communication systems. We also show that a Poisson flow model and the fluid flow model developed by Mitra can be used to bound the buffer content of a two stage automatic transfer line. The potential use of the bounding techniques presented in this paper, of course, transcends well beyond these examples.

Behavior of Machining-Assembly Automatic Transfer Line Systems Adapting a Matching Method. Effects of Rules of Part Combinations.

A matching method is used in many factories to produce high-quality bearings efficiently. In this method, the rule of part combinations affects the production rate and the consumption rate ratio of balls with various dimensions purchased from an outside factory, and an effective rule must be considered. This paper studies the effect of 2 rules of part combinations ; an in-process part rule in which an inner race preferentially selects the outer race which has the maximum number of combinations from outer races stored in buffer storage, and an accuracy rule in which an inner race preferentially selects the outer race which has an accuracy closest to the inner race accuracy. From the numerical analysis, it is shown that the in-process part rule cancels the decrease of the production rate caused by the matching method, and that two rules give different consumption rate ratios of balls.

Stagnation of Material Flow in Closed-Loop Automatic Transfer Line Systems. Effects of System Parameters on Production Rate for High-Precision Adhesive Products.

When high-precision adhesive products are mass-produced, it is necessary to install a closed-loop automatic production system, in which many jigs are used repeatedly and their temperatures are controlled. In this paper, we consider the modelling of jig flow in the system and analyze the effects of system parameters on stagnation of jig flow using the simulation method. The main results are as follows. (1) There exists an optimum number of input jigs which yields the highest production rate. (2) Both a decrease of trouble in the separating stage and an increase in the allowable drop of jig temperature increase the optimum number of input jigs and the production rate. (3) A buffer storage is useful if it is installed before the separating stage.

Machining-Assembly Automatic Transfer Line with a Merge Stage. Approximation Method for Production Rate and Line Behaviour.

Machining-Assembly Automatic Transfer Line with a Merge Stage. Approximation Method for Production Rate and Line Behaviour.

Design of manufacturing systems using queueing models

Design issues in various types of manufacturing systems such as flow lines, automatic transfer lines, job shops, flexible machining systems, flexible assembly systems and multiple cell systems are addressed in this paper. Approaches to resolving these design issues of these systems using queueing models are reviewed. In particular, we show how the structural properties that are recently derived for single and multiple stage queueing systems can be used effectively in the solution of certain design optimization problems.