冰箱防护板冲孔模设计

介绍了防护板的结构特点 ,多孔冲模以及斜面冲孔模具的设计要点 ,并对斜面冲孔结构做了一定的改进 ,使模具的使用寿命和可靠性大大提高 ;加工精度的控制和保证 ,装配技术的改进 ,从而大大缩短了模具装配时间和制造周期。     

德式钳工锤冲孔整形模设计

介绍了一种德式钳工锤冲孔整形模具 ,利用该模具可有效避免德式钳工锤热锻工艺中冲孔时的变形 ,提高了产品质量。并阐述了模具的整体结构及工作过程 ,指出了模具设计要点。     

Properties of Co-doped N-type FeSi2 processed by mechanical alloying

Iron-silicide was produced with a mechanical alloying process and consolidated through vacuum hot pressing. The as-milled powders were of metastable state and fully transformed into the ß-FeSi₂ phase through subsequent isothermal annealing. The as-consolidated iron silicides consisted of an untransformed mixture of α-Fe₂Si₅ and ?-FeSi phases and a partially transformed β-FeSi₂ phase was found in the low density compact. Isothermal annealing was carried out to induce transformation into a thermoelectric semiconducting β-FeSi₂ phase. The transformation behavior of the β-FeSi₂ was investigated utilizing DTA, SEM, and XRD analyses. Isothermal annealing at 830°C in vacuum led to a thermoelectric semiconducting β-FeSi₂ phase transformation, but some residual metallic α and ?-phases were unavoidable even after 96 hours of annealing. The iron silicide microstructures were investigated using SEM and TEM. The mechanical and thermoelectric properties of the β-FeSi₂ materials before and after isothermal annealing are characterized in this study.     

全球铝轧制工业概览系列综述之十二 法国雷纳铝业公司新布里萨克轧制厂

对法国雷纳铝业公司新布里萨克轧制厂作了全面系统的介绍,并对普基公司的情况简介了一下。雷纳铝业公司是世界第五大铝业公司,是全球生产航空航天硬合金材料的第三大公司。雷纳铝业公司在法国本土有两个板带材轧制厂:新布里萨克轧制厂,专门轧制1×××、3×××、5×××系等民用材料;伊苏瓦尔轧制厂,以生产硬合金板材为主。新布里萨克轧制厂1961年开始建设,1967年投产,1992年对原来的3机架热精连轧生产线改为4机架的,仅用了17天时间,未影响生产。该厂有熔铸、热轧、冷轧、精整、维护等车间。热轧线生产能力450kt/a。     

Rapidly solidified hypereutectic Al-Si alloys prepared by powder hot extrusion

Rapidly solidified hypereutectic Al-Si alloys were prepared by powder hot extrusion.By eliminating vacuum degassing procedure.the fabrication routine was simplified.The tensile fracture mechanisms at room temperature and elevated temperature were investigated by SEM fractography.Compared with KS282 casting material,the tensile strength of rapidly solidified Al-Si alloy is greatly improved due to silicon particles refining while its density and coefficient of thermal expansion are lower.than those of KS282.The wear resistance of RS AlSi is better than that of KS282.     

推力轴承工艺与工装的改进

针对推力轴承加工过程中存在的锻造工艺落后、留量大、精度差、切断宽度大等问题,对锻造工艺进行了改进,由自由锻4件合锻改为碾环锻造8件合锻,减少了加工留量,提高了效率;工件分离由车刀切断改为锯片锯断,减少了切断留量和端面留量,节约了原材料,提高了加工工效,降低了生产成本;对锯床进行了技术改造,并制作了新工装,为工艺改进奠定了基础。     

精镗汽轮机轴承箱大径孔

在大型汽轮机零件制造中常见大径(400~950mm)孔的镗削加工,如轴承箱孔、汽缸及汽封圈内孔等。由于内孔尺寸大、常规刀具装置刚度差及操作者技能水平不高,内孔加工很难达到设计技术要求,大径孔精镗加工成为行业制造难题。在分析加工现状的基础上,通过研制新的大径孔精镗刀模块装置、合理利用机床特性和选择切削参数等,形成了一套合理的大径孔精镗工艺方案,满足了精镗汽轮机轴承箱大径孔的技术要求,提高了加工效率。     

一种车载雷达天线转台系统设计

研究了一种二维天线转台,通过对天线转台的工作原理、结构组成和关键技术的研究,设计出一套体积小、重量轻、变形小和高精度等特点的天线转台系统。可为高精度车载转台的设计提供宝贵的理论和实践基础。     

基于在线测量系统的转轴精密磨削加工

精密转轴是高速电主轴的核心零件,其性能的高低直接影响着高速电主轴的加工能力和精度寿命。通过在线测量系统编写数控程序对转轴进行精密磨削加工,安全性高,精度一致性好,能降低劳动强度,提高生产效率。     

一种基于多轴工业机器人的非线性同步控制方法

为了提高机器人的末端轨迹精度,提出了一种基于六轴工业机器人的包含位置误差和同步误差的非线性PD偏差耦合控制策略。该策略无需考虑机器人精确的动力学模型参数,避免了不精确动力学参数的影响。首先建立了基于IRB120型虚拟样机的动力学模型,再利用Simulink和Adams进行联合仿真验证该策略的合理性。仿真结果表明,利用该方法与基于相同规划轨迹的传统非同步控制的力矩前馈算法和PD同步控制算法进行比较,有效地降低了关节同步误差,提高了末端的轨迹精度。