钢管热浸镀锌生产工艺线中速度控制技术探研

热浸镀锌也叫热镀锌,是指将钢管在熔融锌液中浸泡,为积钢管覆盖金属层的一种方式。在热浸镀锌期间,浸锌时间直接影响工艺效果,而控制速度,是控制时间的关键。本文分析了钢管热浸镀锌生产工艺线,重点研究了电磁调速电动机、交流异步电动机调速、变换器几个主要的钢管热浸镀锌生产工艺线中速度控制技术,探究了各技术的应用原理和注意事项等,希望能够对相关工作提供一定帮助。

银亮钢丝生产工艺探讨

国民经济的高速发展,对金属制品即钢丝的尺寸公差、表面质量、光洁度、性能等各项指标的要求会越来越高,为了满足市场的需求,必须生产适应市场要求的银亮钢丝,本文就银亮钢丝生产工艺线进行探讨与研究。

石棉胶乳板生产工艺

石棉胶乳板是以石棉与橡胶乳液为原料以抄取制得的板状材料。主要用于汽缸垫、净排气垫、工业管理等工业设备的密封材料。该工艺线也可以发展为无石棉的新型胶乳板生产工艺线。主要技术指标;容重;0.65～1.10g/cm^2,δ0.5～2。抗张强度:纵向≥100kg/cm^2。

日常维修:无事故企业

叙述了设备日常维修的新构想，这种构想可使生产工艺线不因事故而中断，并可提高设备的工作效率。这个构想的实质是，设备的日常维修不是在它出现故障而不得不停止生产的时候才进行，而是经常地，根据对设备的经常观察而出现必要性时就进行。同时，只要出现设备工作速度减慢或短暂停止就要检修。进行这样的维修需要建立专门工作队，它同设备操作者和看管者保持密切联系。在法国Usinor－Sacilor工业集团中有1250个这样的工作队，而且其数量还在增加。经验表明，它们可以提高设备生产率30％主要靠消除预见不到的设备损坏造成的停工。

郑州宇通客车股份有限公司

郑州宇通客车股份有限公司(原郑州客车厂),是全国14家大客车生产骨干企业之一。1963年起从事大客车制造,具有30多年的实践经验。

A Worsted Yarn Virtual Production System Based on BP Neural Network

Back-Propagation (BP) neural network and its modified algorithm are introduced. Two series of BP neural network models have been established to predict yarn properties and to deduce wool fiber qualities. The results from these two series of models have been compared with the measured values respectively, proving that the accuracy in both the prediction model and the deduction model is high. The experimental results and the corresponding analysis show that the BP neural network is an efficient technique for the quality prediction and has wide prospect in the application of worsted yarn production system.

An improved cross entropy algorithm for steelmaking-continuous casting production scheduling with complicated technological routes

In order to increase productivity and reduce energy consumption of steelmaking-continuous casting(SCC) production process, especially with complicated technological routes, the cross entropy(CE) method was adopted to optimize the SCC production scheduling(SCCPS) problem. Based on the CE method, a matrix encoding scheme was proposed and a backward decoding method was used to generate a reasonable schedule. To describe the distribution of the solution space, a probability distribution model was built and used to generate individuals. In addition, the probability updating mechanism of the probability distribution model was proposed which helps to find the optimal individual gradually. Because of the poor stability and premature convergence of the standard cross entropy(SCE) algorithm, the improved cross entropy(ICE) algorithm was proposed with the following improvements: individual generation mechanism combined with heuristic rules, retention mechanism of the optimal individual, local search mechanism and dynamic parameters of the algorithm. Simulation experiments validate that the CE method is effective in solving the SCCPS problem with complicated technological routes and the ICE algorithm proposed has superior performance to the SCE algorithm and the genetic algorithm(GA).

Schedule for Garment Assembly Line Based on Genetic Algorithm

A new way to solve the scheduling problem ofgarment assembly line based on genetic algorithmwas proposed. The chromosome was decoded usingtask precedence relation and after the operation ofreproduction, crossover and mutation, the globaloptimal result can be obtained. Fitness function wasrepresented by smoothness Index ( SI ). Thesimulation shows that the method proposed in thispaper is better than the conventional way and theoptimized solution can be got in this way.

Press cutting of thin-walled round pipe for producing curvilinear end

In order to obtain a basic understanding of the unwanted distortions in the pipe wall during the press cutting process, the deformation of a thin-walled round pipe to form a curvilinear end was numerically and experimentally studied. Vector analysis was used to study the relationship between the punch shape and the collapse of the cut-end. Stamping experiments on AISI 1020 steel pipe were conducted using different angles a and β defining the shape of the punch. The elasto-plastic finite element method that allows consideration of a ductile fracture was also employed to study the process. The results show that the deformation of the pipe end after press cutting is inβuenced mostly by the shape of the punch. A satisfactory quality of the curvilinear end of the pipe can be obtained if the appropriate geometric parameters of the punch are chosen. The pipe-wall collapse in the upper part of the section is decreased when a and β increase. The recommended values for a and β lie within 30°-50°. The hole on the underside of the punch has less inβuence on the quality of the cut-end, and the wall distortion and the generation of burr on the cut-end can be satisfactorily simulated using the fracture criterion of Brozzo or the normalized criterion of Cockcroft and Latham.

Multi-Objective Genetic Algorithm to Design Manufacturing Process Line Including Feasible and Infeasible Solutions in Neighborhood

This paper treats multi-objective problem for manufacturing process design. A purpose of the process design is to decide combinations of work elements assigned to different work centers. Multiple work elements are ordinarily assigned to each center. Here, infeasible solutions are easily generated by precedence relationship of work elements in process design. The number of infeasible solutions generated is ordinarily larger than that of feasible solutions generated in the process. Therefore, feasible and infeasible solutions are located in any neighborhood in solution space. It is difficult to seek high quality Pareto solutions in this problem by using conventional multi-objective evolutional algorithms. We consider that the problem includes difficulty to seek high quality solutions by the following characteristics： （1） Since infeasible solutions are resemble to good feasible solutions, many infeasible solutions which have good values of objective functions are easily sought in the search process, （2） Infeasible solutions are useful to select new variable conditions generating good feasible solutions in search process. In this study, a multi-objective genetic algorithm including local search is proposed using these characteristics. Maximum value of average operation times and maximum value of dispersion of operation time in all work centers are used as objective functions to promote productivity. The optimal weighted coefficient is introduced to control the ratio of feasible solutions to all solutions selected in crossover and selection process in the algorithm. This paper shows the effectiveness of the proposed algorithm on simple model.

Products and production routes for the catalytic conversion of seed oil into fuel and chemicals: a comprehensive review

With the depletion of fossil resources, there is a need to find alternative resources of fuels and chemicals. The use of renewable feedstock such as those from seed oil processing is one of the best available resources that have come to the fore-front recently. This paper critically analyzes and highlights major factors in the biodiesel industry, such as seeds oil composition, production methods, properties of biodiesel, problems and potential solutions of using vegetable seed oil, the composition, quality and effective utilization of crude glycerol, the catalytic conversion of glycerol into possible fuels and chemicals.