Progressive cutting tool wear detection from machined surface images using Voronoi tessellation method

Tool condition monitoring by machine vision approach has been gaining popularity day by day since it is a low cost and flexible method. In this paper, a tool condition monitoring technique by analysing turned surface images has been presented. The aim of this work is to apply an image texture analysis technique on turned surface images for quantitative assessment of cutting tool flank wear, progressively. A novel method by the concept of Voronoi tessellation has been applied in this study to analyse the surface texture of machined surface after the creation of Voronoi diagram. Two texture features, namely, number of polygons with zero cross moment and total void area of Voronoi diagram of machined surface images have been extracted. A correlation study between measured flank wear and extracted texture features has been done for depicting the tool flank wear. It has been found that number of polygons with zero cross moment has better linear relationship with tool flank wear than that of total void area.     

带台阶的D形橡胶密封圈密封特性分析

使用有限元方法分析一种新型带台阶的D形橡胶密封圈在不同预压缩率、工质压力和结构参数下的密封特性,并将之与相同尺寸的普通D形密封圈进行对比。分析结果表明:与普通D形密封圈相比,带台阶D形密封圈在高预压缩率下能获得更好的密封效果,但使用寿命较短;在低工质压力下,带台阶D形密封圈的密封性能更优,且使用寿命较长;在高工质压力下,2种D形密封圈的密封效果基本一致,但带台阶D形密封圈的使用寿命较短;结构参数H_1/H_2(底座矩形高度与截面弧形高度比)是影响D形密封圈密封性能的重要参数,当H_1/H_2的比值为3∶1时,2种D形密封圈的综合密封性能最优。     

An error control approach to tool path adjustment conforming to the deformation of thin-walled workpiece

Producing an accurate part mainly depends on the position and orientation of the cutting tool with respect to the workpiece which is mainly influenced by the rigid body motion of the workpiece and the elastic deformation of workpiece-fixture-cutter system. For the purpose of minimizing the machining error, a new modification strategy of the nominal tool path is not that directly compensate the control commands of the machine tools, but that modify the cutter location source file (CLSF) from the computer aided manufacturing (CAM) system by means of the proposed modification model on the basis of the prediction deviation, namely, the deviation of the cutting tool relative to the workpiece in computer numerical control (CNC) machining operation. Therefore, it is not only simpler, but also easier implemented by common manufacturing engineer. The effectiveness of the proposed strategy is verified by a machining example.     

汽车继电器的几项新技术

阐述了汽车继电器开发中应重视的几项新技术：可靠性技术、寿命试验技术以及计算机分析技术等。介绍了汽车继电器可靠性试验设备性能、电寿命的试验方法及试验设备，给出了试验过程的控制电路框图。通过继电器电磁场、运动和应力仿真，以达到继电器磁系统和各部件优化设计，提高继电器机械寿命和电寿命。     

浅谈我国绿色建筑几点现状问题及发展策略

通过对我国现阶段绿色建筑建设现状几点问题的审慎、严谨、细致的科学分析,提出符合我国文化背景和社会现状的绿色建筑发展策略,以期促进我国绿色建筑的推广应用。     

佛教的生命哲学——以《大乘百法明门论》为中心研究

佛教学说是一个博大精深、具有浓厚神秘主义色彩的理论体系,它所包涵的内容极为丰富复杂,但从它的基本出发点和精神实质来看,佛教的思想核心中最为根本的就是它的生命哲学:从生生灭灭、生生死死不稳定痛苦的觉受里头,教我们对这种生命的体验里头看清生命存在的实相,从而觉悟、断除烦恼,脱离出生死苦海。本文以《大乘百法明门论》为我们示现通达生命实相的具体实践修行法门贯穿着古典认识论来探讨佛教的生命哲学。     

Tool Length-Dependent Stability Surfaces

Abstract

This article describes the development of three-dimensional stability surfaces, or maps, that combine the traditional dependence of allowable (chatter-free) chip width on spindle speed with the inherent dependence on tool overhang length, due to the corresponding changes in the system dynamics with overhang. The tool point frequency response, which is required as input to existing stability lobe calculations, is determined analytically using Receptance Coupling Substructure Analysis (RCSA). In this method, a model of the tool, which includes overhang length as a variable, is coupled to an experimental measurement of the holder/spindle substructure through empirical connection parameters. The assembly frequency response at the tool point can then be predicted for variations in tool overhang length. Using the graphs developed in this study, the technique of tool tuning, described previously in the literature, can then be carried out to select a tool overhang length for maximized material removal rate. Experimental results for both frequency response predictions and milling stability are presented.     

Pain, depression, and physical functioning following burn injury.

Objective: Little is known about how pain and depression after burn injury may influence long-term outcomes such as physical functioning. This prospective study examined associations between pain, depression, and physical functioning in a sample of burn injury survivors. Design and Participants: Questionnaires assessing pain, depression, and physical functioning were completed by 64 (52% of original sample) adult burn survivors shortly after discharge from burn care and at 1- and 2-year follow-ups. Results: Pain and physical functioning improved over the 2 years of the study, whereas depression levels were stable. Pain and depression were associated with poorer physical functioning over time, but associations varied according to the time span under consideration. Also, the association between pain and physical functioning was strongest among persons with higher depression scores. Conclusions: Pain and depression may contribute independently to compromises in physical functioning. The co-occurrence of pain and depression represents even greater risk for reduced physical functioning over time among burn survivors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)