汽轮机转子叶根勾槽的塞规研究

介绍了汽轮机转子叶根槽的样式和加工工艺方法。针对勾槽深度检验测量困难的问题,通过实例,阐述了利用尺寸链知识和光滑极限量规技术条件设计塞规的方法。     

第六讲 第二类工艺尺寸的计算

第二类工艺尺寸,指的是从还需继续加工的表面注出的工艺尺寸,等到这个表面加工以后,工艺尺寸就不存在了。我们还是用生产实际中的例子来说明它的计算方法。例一第一讲中提到的那个在齿轮孔中插键槽的问题(参阅图1-4和图1-5),现在可以把它彻底解决。问题是这样的:齿轮孔按尺寸φ84.8~(+0.07)精镗后,再插键槽、淬火,最后磨孔至φ85~(+0.035)。要保证键槽深度尺寸为87.9~(+0.33),问应该按什么尺寸插键槽?     

高强度螺栓圆角冷挤压工艺研究

高强度螺栓头下圆角需进行冷滚压强化工艺，以提高螺栓的疲劳强度。通过研究实践证明，滚压前螺栓头下圆角的尺寸公差是影响滚压质量的关键因素之一。本文就滚压前的螺栓头下圆角尺寸公差与滚压变形的关系，研究了确定滚压圆角尺寸公差数值的方法，并给出了确定滚前圆角尺寸公差数值与滚压深度的关系线图。     

冲压套圈热处理工艺试验

对JHOR/40 70冲压套圈热处理试验所用设备、工艺和工艺参数作了介绍 ,并对热处理后的尺寸、变形、组织结构、渗层深度、残余应力及残余奥氏体进行了测定与分析。分析结果表明 ,尺寸及组织等均达到有关技术要求。附图1幅 ,表 1个。     

发动机缸盖进排气门深度尺寸测量检具设计

分析了发动机缸盖进排气门深度尺寸的特点,针对空间深度尺寸无法直接测量的问题,利用中介载体进行间接测量,解决了类似尺寸用常规方法无法测量的问题,实现了间接测量检具的实际应用。     

基于体硅工艺的定位平台制作工艺分析研究

介绍了一种基于体硅工艺的大尺寸、大深宽比的纳米级定位平台的制作工艺。对定位平台的制作中的关键工艺进行的分析，总结了导致器件失效的主要原因，探讨了减少失效的方法。同时介绍了一种可行的面内侧面压阻的加工方法。通过对深度反应离子刻蚀（DRIE）工艺参数的调整成功了刻蚀出了大尺寸、大深宽比的结构释放窗口，释放了最小线宽为2.5μm，厚度为50微米的梳齿结构。研制了一种良好性能的集成位移检测的纳米级定位平台。     

工艺保证尺寸的控制

为工艺保证尺寸归纳了定义,提出工艺保证尺寸的控制方法,并介绍了典型实例。针对工艺保证尺寸的控制,本文提出自己的观点和方法,供有关各界参考。     

计算机在工艺尺寸式法中的应用

本文介绍在工艺尺寸式法中,如何采用计算机计算工艺尺寸链的方法。一、工艺尺寸式法工艺尺寸式法是一种新近出现的尺寸链计算方法,即尺寸跟踪的解析计算法。其特点,第一仅用英文字母表示尺寸关系;第二不用画图即可准确地写出工艺尺寸式,以表示工艺尺寸链中各组成环尺寸之间     

工艺尺寸式及其方法

本文提出了一种非常适合计算机辅助工序尺寸设计的工艺尺寸式法，并简要介绍了工艺尺寸式原理及工艺尺寸关系的查找方法。通过实例说明，工艺尺寸式与工艺尺寸链相比具有不需绘图，不易出错，寻找工艺尺寸关系方便，理论完善，通用性强等特点，指出用工艺尺寸式代替工艺尺寸链无论对教学还是对生产实际都有重要意义。     

微磨料空气射流加工特性研究

通过微磨料空气射流加工普通平板玻璃的试验研究,分析了加工时间、空气压力、磨料流量、喷射距离、喷射角度、磨料种类、喷嘴结构和尺寸等加工工艺参数与微磨料空气射流加工的材料冲蚀率及玻璃表面冲蚀加工凹坑尺寸（凹坑直径和凹坑深度）之间的关系,得出了这些工艺参数对微磨料空气射流加工效果的影响规律。结果表明：喷射距离对材料冲蚀率和冲蚀凹坑的尺寸影响最大,存在一个可以获得最大冲蚀率和加工深度的最佳喷射距离;喷嘴的形状、尺寸和喷射角度的不同直接改变加工凹坑的轮廓,是影响微磨料空气射流加工轮廓结构形状的关键因素。     

A technique for quantitative assessment of three-dimensional motion with applications to human joints

A technique is developed for quantitative measurement of general three-dimensional motion, and this technique is applied to the kinematics of anatomical joints. The spatial locations of three orthogonal points representing coordinate frames on each member of the joint are measured during motion of the joint by photo encoders of a three-dimensional mechanical pointer. Kinematic calculations are used to derive, from the experimentally collected data, the six orthogonal components of the motion of one member relative to the other. The accuracy of this technique is presented. Applications to the knee and ankle are discussed.     

正交车铣偏心加工三维颤振稳定性的研究

针对正交车铣复杂运动产生变深度、变厚度的切削特性,基于其加工原理采用解析法提出三维颤振稳定域的理论模型.在模态试验基础上,仿真分析正交车铣偏心加工颤振稳定域叶瓣图,结果表明正交车铣加工产生颤振的条件除了与铣刀几何形状和啮合条件、机床结构的频响应函数、工件材料特性等有关外,主要与铣刀轴转速和切削深度密切相关.在正交车铣切削颤振稳定域试验过程中,切削力频谱分析的结果表明:当刀齿切入频率在力频谱中起主导作用时,切削过程是无颤振和稳定的;当系统结构模态频率在力频谱中起主导作用时,将产生颤振并测得切削力和表面粗糙度值都大于或高于无颤振情况.因此该理论模型及仿真结果可以有效预测正交车铣偏心加工颤振稳定性,为其加工表面质量和加工效率提供理论指导.     

MACHINING RESIDUAL STRESSES IN AISI 316L STEEL AND THEIR CORRELATION WITH THE CUTTING PARAMETERS

It is well known that machining results in residual stresses in the workpiece. These stresses correlate very closely with the cutting tool geometrical parameters as well as with the machining regime. This paper studies the residual stress induced in turning of AISI 316L steel. Particular attention is paid to the influence of the cutting parameters, such as the cutting speed, feed and depth of cut. In the experiments, the residual stresses have been measured using the X-ray diffraction technique (at the surface of the workpiece and in depth). The effects of cutting conditions on residual stresses are analyzed in association with the experimentally determined cutting forces. The orthogonal components of the cutting force were measured using a piezoelectric dynamometer.     

微细铣削切削力正交实验研究

在自行研制的三轴联动微细铣床上,选取典型微三维零件特征进行铣槽和侧铣两种工况正交铣削实验,对微细切削力进行测量和分析。深入研究了主轴转速、轴向切深、每齿进给量等工艺参数对微细切削力的影响规律,以优化加工参数,提高微铣削的加工效率和加工精度。     

蛇形机器人桥梁缆索攀爬步态控制研究

使用基于迭代链拟合与关键帧提取的蛇形机器人缆索攀爬步态生成方法,对一种正交关节蛇形机器人桥梁缆索攀爬步态控制进行了研究。该方法可建立蛇体骨干曲线定向位移与底层驱动器输入之间的联系,可将传统的骨干曲线法和控制函数法两种步态生成方法的优点有效地结合。使用该方法生成步态既可直观地得到骨干曲线的形状及运动趋势,又可得到以关节号和时间为变量的控制函数。该方法可有效提高蛇形机器人桥梁缆索攀爬的安全性、步态灵活性,同时,也便于控制底层驱动器。最后,通过实验验证了所提出方法的有效性。     

轴承保持架低压脉冲真空氮碳共渗工艺

分析轴承保持架低压脉冲真空氮碳共渗工艺原理,对影响保持架表面白亮层深度和表面硬度的脉冲工艺参数:脉冲幅度、保压时间及总脉冲时间进行了正交试验。应用正交试验极差分析法分析了脉冲工艺参数与白亮层深度和表面硬度的影响趋势,最终确定出给定试验条件下的最佳脉冲工艺参数。     

Optimization of friction welding by taguchi and ANOVA method on commercial aluminium tube to Al 2025 tube plate with backing block using an external tool

The aim of the present work is to optimize the Friction welding of tube to tube plate using an external tool (FWTPET) with clearance fit of commercial aluminum tube to Al 2025 tube plate using an external tool. Conventional frictional welding is suitable to weld only symmetrical joints either tube to tube or rod to rod but in this research with the help of external tool, the welding has been done by unsymmetrical shape of tube to tube plate also. In this investigation, the various welding parameters such as tool rotating speed (rpm), projection of tube (mm) and depth of cut (mm) are determined according to the Taguchi L₉ orthogonal array. The two conditions were considered in this process to examine this experiment; where condition 1 is flat plate with plain tube Without holes [WOH] on the circumference of the surface and condition 2 is flat plate with plane tube has holes on its circumference of the surface With holes [WH]. Taguchi L₉ orthogonal array was utilized to find the most significant control factors which will yield better joint strength. Besides, the most influential process parameter has been determined using statistical Analysis of variance (ANOVA). Finally, the comparison of each result has been done for conditions by means percentage of contribution and regression analysis. The general regression equation is formulated and better strength is obtained and it is validated by means of confirmation test. It was observed that value of optimal welded joint strength for both tube without holes and tube with holes are to be 319.485 MPa and 264.825 MPa, respectively.

     

MACHINING OF CORTICAL BONE: SURFACE TEXTURE,SURFACE INTEGRITY AND CUTTING FORCES

Cutting, drilling and reaming of human bone are conducted in total joint replacement procedures and the placement of dental implants. In the current study orthogonal machining of cortical bone was performed and the cutting and thrust forces, as well as the machined surface quality, were evaluated over a range of osteon orientations and cutting conditions. Results showed that cutting perpendicular to the osteons resulted in the highest machining forces, largest surface roughness and extensive sub-surface damage for some parametric conditions. The average surface roughness of the machined bone ranged from 1 μm to over 70 μm, was largest for positive rake angle tools and increased with the depth of cut. There was no correlation between the cutting forces and machined surface quality. While negative rake angle tools resulted in the largest cutting forces, they provided the lowest surface roughness and highest apparent surface quality. Overall, the results show that orthogonal cutting of bone can result in near-surface damage that reduces the degree of contact between bone and implanted devices and is potentially detrimental to the post-surgical recovery rate.     

Solder joint inspection with multi-angle imaging and an artificial neural network

Machine vision has been widely deployed in many industrial applications. However, for solder joint inspection, it has yet to reach the desired maturity level. This paper presents a new inspection methodology using images from both orthogonal and oblique viewing directions to the solder joint. The oblique view was made possible through a mirror pyramid. Image capturing and selection of the soldered region were done manually, but could be automated if the positional coordinates were known. Combined orthogonal and oblique gray-level images at the pixel level were directly input to an artificial neural network (ANN) for processing, eliminating the need to determine heuristic features. Learning vector quantization architecture was used as the classifier. This study was focused on geometry-related joint defects, namely, excess and insufficient. Comparisons show that the oblique view provides more useful information compared to the orthogonal view. The experimental results indicate that the proposed system has an improved recognition rate and good resilience to noise.     

MACHINING OF CORTICAL BONE: SURFACE TEXTURE, SURFACE INTEGRITY AND CUTTING FORCES

Cutting, drilling and reaming of human bone are conducted in total joint replacement procedures and the placement of dental implants. In the current study orthogonal machining of cortical bone was performed and the cutting and thrust forces, as well as the machined surface quality, were evaluated over a range of osteon orientations and cutting conditions. Results showed that cutting perpendicular to the osteons resulted in the highest machining forces, largest surface roughness and extensive sub-surface damage for some parametric conditions. The average surface roughness of the machined bone ranged from 1 μm to over 70 μm, was largest for positive rake angle tools and increased with the depth of cut. There was no correlation between the cutting forces and machined surface quality. While negative rake angle tools resulted in the largest cutting forces, they provided the lowest surface roughness and highest apparent surface quality. Overall, the results show that orthogonal cutting of bone can result in near-surface damage that reduces the degree of contact between bone and implanted devices and is potentially detrimental to the post-surgical recovery rate.