A model for cutting forces generated during machining with self-propelled rotary tools

In this paper, a force model for self-propelled rotary tool is presented. Conventional oblique cutting force predictions were reviewed and extended to predict the cutting forces generated during machining with the self-propelled rotary tools. The model presented is based on Oxley's analysis and was verified by cutting tests using a typical self-propelled tool. Good agreement was obtained between the predicted and the experimentally measured forces under a wide range of cutting conditions. The effect of different cutting conditions on the friction coefficient along the chip/tool interface and tool rake face normal force were also presented and discussed.     

形变氮化08F钢冲击断口的分形研究

利用垂直截面法测量了０８Ｆ钢经不同形变氮化复合后冲击断裂表面的分形维数。结果表明，材料的冲击能Ａ和沿裂纹扩展方向剖面Ｋｏｃｈ曲线的分形维数Ｄ地均随表变量的增而增加。分形维维数Ｄ与ｌｎＡ之间呈正变化的关系，且满足下列关系式：ｌｎＡｋ＝４９．４３ＫＦ－５１．４４。     

CRYSTALLOGRAPHIC ANALYSIS OF THE LATH MARTENSITE TRANSFORMATION IN Fe-Ni-Mn ALLOY

1.IntroductionBased on the concept of an invariant plane strain (IPS), phenomenological theory of martensite transformation (PTMT) is established[1-3]. In this case, an invariant plane is obtained by self-accommoda-tion effect between different martensitic variants, and the formula which reveals this self-accommoda-tion effect can be written as …     

Q-52-51型摩托车车轮轮毂开裂原因分析

检测和分析了Q-52-51型摩托车车轮轮毂从材料成分，力学性能和金相组织。结果表明，轮毂在径向冲击检测时开裂的主要原因是镁含量偏高，以及热处理加热温度高造成组织过热所致。     

Discussion on compact mechanism of air-stream and synchro-formed clamp plate impact molding

1 .Introduction Due to many advantages such as simple molding machine structure high compact compaction of sand mold, speed and well-distributed the air-stream impact molding method However, has been extensively used in production.when this molding method is applied to mold complicated pattern with wider top surface and deep     

钛合金等温锻造进展

等温锻造是一种先进的加工工艺。本文从钛合金高温变形特性、等温锻造参数选择、模具设计、润滑剂摩擦特性等诸方面全面地介绍了这种先进的锻造工艺，它的应用前景及发展方向。     

超声冲击细化22SiMn2TiB超高强钢焊接接头晶粒研究

晶粒细化有助于提高焊接接头性能。应用超声冲击装置对母材为22SiMn2TiB、焊接材料为Cr20Ni10Mn6的异种钢焊接接头进行冲击强化试验,研究了冲击区域金属的塑性变形情况。用扫描电镜观测冲击层断面区,可看到冲击塑性变形层达到150μm,其中晶粒细化区超过50μm;用X-Ray衍射仪测试冲击层细晶衍射线宽化现象,并计算冲击层细化晶粒尺寸,计算结果表明母材冲击层平均晶粒尺寸为63nm,焊缝金属冲击层平均晶粒尺寸为82nm。研究表明,超声冲击时冲击针的高频大能量输入,引起冲击层金属晶格畸变,位错增殖、运动、重排,是晶粒细化的主要原因。     

New method for determination of the pose of the grinding wheel for thinning drill points

Traditionally, twist drills are reconditioned by thinning the web so the correct chisel edge length is restored. Recently, thinning has been included in the original design of drills so as to reduce torque and tool force. Because the International Standards Organization (ISO) has a system which can comprehensively model conventional twist drills but cannot model thinning specifications, this paper presents a system for precise mathematical modeling and CNC control of a 6-axis grinding workstation for drill thinning. The presented method determines the position and orientation of the grinding wheel based on the evaluated rake and clearance angles of ISO standards for 2-flute twist drills. The mathematical model and background are discussed. For verification and demonstration, two experimental drills are produced to the identical ISO standard except that one is thinned. The modeling herein is of value to industry and research if incorporated into computer software for drill design and manufacture. It is suitable for linear notch-type cutting with controlled variable rake angle along the secondary cutting edge for purposes of thinning, notching, dubbing and advanced drill research.     

矫直辊曲线及调整角度计算程序

简述了矫直辊辊形曲线计算原理，并作了定性分析；根据解析法与椭圆法归纳出辊形曲线程序设计的数学模型联；计算出了各种钢管对应的矫直辊调整角度。     

Chip geometries during high-speed machining for orthogonal cutting conditions

The originality of this work consists in taking photographs of chips during the cutting process for a large range of speeds. Contrary to methods usually used such as the quick stop in which root chips are analyzed after an abrupt interruption of the cutting, the proposed process photographs the chip geometry during its elaboration. An original device reproducing perfectly orthogonal cutting conditions is used because it allows a good accessibility to the zone of machining and reduces considerably the vibrations found in conventional machining tests. A large range of cutting velocities is investigated (from 17 to 60 m/s) for a middle hard steel (French Standards XC18). The experimental measures of the root chip geometry, more specifically the tool-chip contact length and the shear angle, are obtained from an analysis of the pictures obtained with a numerical high-speed camera. These geometrical characteristics of chips are studied for various cutting speeds, at the three rake angles −5, 0, +5° and for different depths of cut reaching 0.65 mm.