A Six-sigma approach for benchmarking of RP&M processes

This paper presents a methodology of using six-sigma quality tools for benchmarking of rapid prototyping & manufacturing (RP&M) processes. It involves the fabrication of a geometric benchmark part and a methodology to control and identify the best performance of the process to reduce the variablity in the fabricated parts. The approach is demonstrated with a case study based on the direct laser sintering (DLS) process for prototyping using plastic powder. In the case study an identified set of six-sigma/ statistical process control tools is employed to determine and best tune factors affecting the desired outcomes of the built parts.     

Development of an expert system for cold forging of axisymmetric product

This paper deals with an automated computer-aided process planning and die design system by which the designer can determine operation sequences even if they have little experience in process planning and die design for axisymmetric products. An attempt is made to link programs incorporating a number of expert design rules with the process variables obtained by commercial FEM softwares, DEFORM and ANSYS, to form a useful package. The system is composed of four main modules. The process planning and the die design modules consider several factors, such as the complexities of preform geometry, punch and die profiles, specifications of available multi-former, and the availability of standard parts. They can provide a flexible process based on either the reduction in the number of forming sequences by combining the possible two processes in sequence, or the reduction of deviation of the distribution on the level of the required forming loads by controlling the forming ratios. In the die design module optimal design technique and the horizontal split of the die insert were investigated for determining appropriate dimensions of components of the multi-former die set. It is suggested that the proposed method can be beneficial for improving the tool life of the die set in practice.     

An integrated system for process planning and cost estimation in hole making

The process planning function plays a critical role not only in computer integrated manufacture, but also in the economics of batch manufacturing. This paper describes the development of a generic knowledge-based system for process planning and cost estimation in the hole making process. The main function of the system, besides estimating the cost of production, is to recommend appropriate processes, their sequence and their respective machining conditions in order to obtain the required product specifications. The system has been implemented in a manufacturing organisation. The results obtained have indicated that in addition to cost savings the system also preserves the consistency in planning and cost estimation.     

谈化学二氧化锰生产过程中的某些技术问题

较全面地阐述了化学二氧化锰生产工艺中的浸出除杂、提高视比重等技术问题，提出了一些有益的见解，总结了某些可用的经验，对发展化学二氧化锰生产有一定的现实意义。     

基于虚拟实景和Perl的火电厂教学系统

基于静态图像的虚拟现实技术是一种提供初步VR体验的虚拟现实技术。针对火电厂多媒体教学,介绍了基于该技术的工作原理、基本特色、开发系统的组成及其在火电厂多媒体远程教学中的典型应用。同时为系统增添了简单实用的教学搜索。     

超声纵波换能器用于平测时的测距修正方法研究

研究了超声纵波换能器用于平测时的测距修正方法.首先,根据弹性波理论分析了利用平测布置代替对测布置测量波速时的实际物理意义;然后,分析了两种换能器布置方式的真实传播距离并通过设计混凝土试件切割-测量实验进行了两种布置方式的声时对比;最后,根据实验数据在对测回归直线方程的基础上提出了计算换能器平测布置修正测距的最小二乘法....     

Maximum-likelihood mixture factor analysis model and its application for process monitoring

In the present paper, a mixture form of the factor analysis model is developed under the maximum-likelihood framework. In this new model structure, different noise levels of process variables have been considered. Afterward, the developed mixture factor analysis model is utilized for process monitoring. To enhance the monitoring performance, a soft combination strategy is then proposed to integrate different local monitoring results into a single monitoring chart, which is based on the Bayesian inference method. To test the modeling and monitoring performance of the proposed mixture factor analysis method, a numerical example and the Tennessee Eastman (TE) benchmark case studies are provided.     

近距离煤层联合开采技术的应用

葛店煤矿N31采区有两层可采煤层,距离很近,煤层中间岩层平均厚度为2.6 m。葛店煤矿采取了上下两层煤同时开采的方式,实现了安全回采,提高了煤炭回收率,带来显著的经济效益。     

E-learning系统中学习评价的研究

针对目前E-learning系统中不能全面地对学员的学习情况进行评价的问题,提出了一个基于模糊综合评判法的E-learning学习评价综合评判模型,并用C语言对所提出的模型进行了程序实现。把学生的学习数据及运行结果进行对比分析可知:模糊综合评判法能综合考虑学员学习过程中表现出的各种因素,从而能得到更全面、更准确的评价结果。     

MLCC装配质量优化研究

针对本所产品中多层陶瓷电容器(MLCC)在经过环境试验后出现的失效问题,通过对失效原因进行分析,结合生产实际情况,进行了技术改进.制作了技术改进前后的试验板,经过环境试验后测试,结果表明,未改进前的试验板中的MLCC出现问题,而改进后的试验板没有发现问题.最后对故障MLCC进行了DPA检查,结果发现MLCC端头出现45°角裂纹.试验结果表明经过技术改进后有效地解决了MLCC装配质量问题,提高了产品装配合格率,达到了预期的效果.