AFA 3G燃料棒下端塞电子束焊产生气胀的分析

宜宾核燃料元件厂在AFA 3G燃料棒首次产品合格性鉴定中发现，大批下端环缝焊产生了气胀的焊接缺陷。本文分析了产生气胀缺陷的原因，并介绍了针对其原因进行的各种试验。结果表明，改变焊接参数，即提高焊接速度和适当控制电子束流强度，是解决燃料棒焊接气胀缺陷的最好途径。     

Design of internal pins in injection mold CAD via the automatic recognition of undercut features

A methodology to deal with the automatic design of internal pins in injection mold CAD via the automatic recognition of undercut features is developed. The approach to automatically identifying the undercut features is first proposed. For the given parting directions, all the inner and outer undercut features are identified based on the topological relationship of geometrical entities. The outer edge loop, which represents the largest cross-section boundary along the given parting directions, is extracted and patched up. The surfaces of molding are then identified based on the classifications of their geometrical entities. To identify the deep inner undercuts in the molding, the projection of the main core, internal pins and their bounding boxes along the parting direction and the pin withdrawal direction are generated. Upon determination of whether the bounding boxes of any two internal pins and the main core projection have intersection area, the deep inner undercuts are located. The complete methodology is finally implemented and verified through case studies and the efficiency of the methodology in handling complex molded parts is thus illustrated.     

关于渐开线标准齿轮最少齿数的分析

通过理论分析，给出了范式法加工渐开线标准齿轮避免根切的最少齿数的一般公式，该公式适用于渐开线齿轮根切、干涉的分析，可作为标准齿轮传动设计中齿数选择和是否采用变位齿轮传动的依据。     

Systematic approach for automated determination of parting line for die-cast parts

The parting line decision for die-cast parts is a non-trivial task, which depends upon a number of factors related to the part geometry and the die-casting process requirements. This is a crucial decision which not only affects the design and manufacturing of the die-casting die but the part manufacturing as well. Normally, a die-casting die-design expert invests a lot of time, effort and resources to take this decision, which affects the part manufacturing lead time and cost. A systematic approach for automated determination of the parting line for die-cast parts is presented in this paper. Unlike the previous systems, which consider part geometric factors only, the system proposed in this paper also considers the die-casting process requirements to determine the parting line in a systematic and automated manner. Here we discuss classification of the die-cast part surfaces, identification of undercuts and protrusions, identification of parting line regions, and determination of the parting line. The system generates a number of feasible parting lines in a given parting direction after applying the die-casting process requirements. Finally, the most suitable parting line is determined from the feasible parting lines considering the industry best practices. The results obtained from the system are similar to those of the industry. The proposed system would prove to be a major step towards automation of the die-casting die design, leading to design–manufacturing integration of the die-casting process.     

少齿数Logix齿轮的齿形设计

L ogix齿轮是依据全新的齿形理论所提出的一种新型齿轮。本文分析了 L ogix齿轮的根切现象 ,在此基础上根据该齿形的特点完成了少齿数齿轮的齿形设计 ,并绘出了少齿数 L ogix齿条、齿轮的图形。     

基于MATLAB的齿轮根切建模分析

从目前广泛采用的齿轮范成原理出发,分析了根切产生的原因及对齿轮传动的影响,根据齿条刀具加工出的齿轮渐开线和齿根过渡曲线方程,推导出求根切圆和根切量的计算公式.应用MATLAB软件对不同齿数和模数进行根切量的精确计算,并用Pro/E软件进行虚拟环境下的根切模拟,进而分析齿数和模数对根切量的影响情况,以及根切量与齿轮实际啮合线段的关系,最终得出一定程度上的根切对齿轮传动是无害的,只会影响齿轮强度,在实际齿轮传动应用中,这在一定程度上是允许的.     

Optimization of Plasma Arc Welding Parameters by Using the Taguchi Method with the Grey Relational Analysis

The optimal parameters process of plasma arc welding (PAW) by the Taguchi method with Grey relational analysis is studied. The Grey relational grade is used to find optimal PAW parameters with multiple response performance characteristics. The welding parameters (welding current, welding speed, plasma gas flow rate, and torch stand-off) are optimized with consideration of the multiple response performance characteristics (the penetration of root, the weld groove width, and the weld pool undercut). As a result, the improvement percentage of the Grey relational grade with the multiple performance characteristics is 31.8%. It is shown that the multiple response performance characteristics are greatly improved through this study.     

自然崩落法在中厚矿体中的应用研究

自然崩落法是一种高效率的地下采矿方法。我院在金山店铁矿对该采矿方法进行了卓有成效的试验研究，取得了圆满的成功。其试验矿秧的地质矿量达２８．４万ｔ，属建国以来规模最大的一次试验。本文主要论述了矿石的可崩性和应力状态的调查、分析与计算；崩矿过程的室内模拟实验；现场回采与放矿的生产试验。最后依据试验结果，对该采矿方法所取得的巨大技术经济效果作了评价。     

微线段齿轮的根切分析

对微线段齿轮的根切现象进行了分析,推导了不发生根切的最小齿轮齿数的计算公式,通过列表计算可知,根切齿数并不是在齿轮实际齿顶部分达到最大值,而是在接近中间的某一点达到最大值,最后通过计算机仿真图形进行了验证。     

翅片管路焊接接头断裂原因分析

通过KYKY2800扫描电镜等技术手段对翅片管路焊接接头进行失效分析。分析表明,焊缝与2#环管的焊趾处存在有不连续的咬边,造成应力集中;在交变应力的作用下于咬边处产生微裂纹,并沿一定方向扩展（同时材料的不均匀性也为裂纹的扩展提供了有利条件）,直至最后疲劳断裂,造成失效。最后提出了预防措施。