Measurement of lathe Z-slide straightness and parallelism using a flat land

A method is described to measure the straightness of travel of the carriage of a single-point diamond turning machine. The method also measures the slide parallelism to the workhead spindle. A cylindrical artifact was produced on the lathe and used as a straightedge. A flat land was cut in the artifact that was parallel to the workhead axis of rotation. The flat land was measured with a LVDT indicator. The method was demonstrated on a Moore Special Tool Co. M18 Aspheric Generator. The quality of measurements achieved were better than 0.1 μm.     

A multi-spectrum analysis of surface roughness formation in ultra-precision machining

The formation of surface roughness in ultra-precision diamond turning is investigated using a multi-spectrum analysis method. The features on a diamond turned surface are extracted and analyzed by the spectrum analysis of its surface roughness profiles measured at a finite number of radial sections of the turned surface. It is found that the tool feed rate, the spindle rotational speed, the tool geometry, the material properties, as well as the relative tool-work vibration are not the only dominant components contributing to the generation of surface roughness. The material induced vibration caused by the variation of material crystallography is another major factor. The vibration causes a significant variation of the frequency of the surface modulation of the machined surface. With the use of the multi-spectrum analysis method, it is possible to conjecture the patterns of this vibration as well as to evaluate the properties of the workpiece materials.     

数控车床用于旋塞及气瓶阀锥螺纹加工

介绍了数控车床加工旋塞塞体与气瓶阀锥螺纹的方法，给出了详细的数控加工程序。     

Automatic restart control system for electrochemical machining

This paper describes the development of a microprocessor-based automatic restart control system (arcs) capable of eliminating flaws caused by restarts during the electrochemical machining (ecm) process. This makes ecm a viable cost-effective technique for producing precision parts previously handled by conventional methods.     

微/纳米CVD金刚石涂层的制备

使用热丝化学气相沉积(HFCVD)装置,在以WC - CO硬质合金为衬底,采用调节涂层生长参数,制备出性能优良的微/纳米金刚石涂层.用SEM,AFM,Raman表征微观结构和表面品质.采用压痕法评估涂层的结合性能,并与微米金刚石涂层、纳米金刚石涂层进行比较.结果显示,当生长气压由3.3 kPa降为1.0 kPa时,底层的微米级晶粒逐渐被上层纳米级晶粒覆盖,并且涂层表面显露出纳米金刚石涂层特性.在结合性能实验中也指出,微/纳米金刚石涂层的结合性能比纳米金刚石涂层要优异.     

Characteristic numbers to describe the detail transfer quality of electro-chemical machining

For reproducing processes such as electrochemical machining (ecm) the accuracy of the reproduction is an important process parameter. Characteristic numbers which are a measure of this accuracy are proposed in this paper. Due to the non-linearity of the process a detail transfer function, which is helpful in linear cases, cannot be used, as will be shown from experimental work. Based on the same experiments, a characteristic radius and the standard deviation of a normal profile are proposed to describe the quality of the detail transfer. These numbers, which are easily interpreted criteria for quality and accuracy, have been proved to be almost independent of the geometry. Although developed for optimizing the ecm process, these values are also valid for edm and other reproducing processes. The usefulness of the characteristic numbers is illustrated by a comparison of continuous and pulsed ecm processes.     

Effect of a combined machining/burnishing tool on the roughness and mechanical properties

Burnishing is a cold working surface treatment process in which plastic deformation of surface irregularities occurs by exerting pressure through a very hard and a very smooth roller or ball on a surface to generate a uniform and work‐hardened surface. This treatment occurs generally after the machining process. In this study, a new combined machining/burnishing tool is designed and is fabricated. This tool allows for generating simultaneously the machining (turning) and the burnishing of the cylindrical surface using a turning machine. First, turned surfaces at different conditions, sketches, finishing and half finishing were performed using only the cutting tool. The evolutions of a surface roughness parameter and the technological time relative to every test condition have been investigated. Second, using the combined machining/burnishing tool at coarse conditions, the evolutions of the surface roughness and the technological time have been also investigated. A comparison among the parameters obtained under different machining conditions and those obtained using the combined machining/burnishing tool has been carried out. Moreover, the analyses of the layers obtained on the combined machined/burnished surface have shown that the burnishing process induces compressive residual stresses on the subsurface treated specimens. Copyright © 2013 John Wiley & Sons, Ltd.     

影响单点金刚石切削表面质量的因素

单点金刚石切削(single point diamond turning,简称SPDT)是一种使用纳米金刚石刀具进行加工的生产过程。而纳米单晶金刚石刀具具有刃口锋利、可反复成形和耐磨性高等特点。该方法能够使微米至亚微米级制造组件的形状精度和表面粗糙度控制在纳米级的范围内。单点金刚石切削优异的表面成形质量和面形精度,使该技术被广泛地应用于制造各种精密机械和光学部件,如注射成型塑料镜头和扫描反射镜。虽然单点金刚石切削满足了很多高精密零件的制造需求,但目前所了解的影响因素和表面生成的机制仍不完善,在生产中有很多因素会影响到单点金刚石的表面质量和面形精度,如主轴转速、进给速度和切削深度等,本文对此进行了分析。     

微结构功能表面的金刚石超精密加工仿真与试验

为解决微结构功能表面的金刚石超精密加工过程中,难以经济而灵活地预测表面质量及加工条件对加工表面质量的影响的问题,以自行设计的带有快速伺服刀架的超精密机床为基础,采用Matlab/ Simulink模块建立正弦波微结构功能表面金刚石超精密加工过程的动态仿真模型。利用该模型,不仅可以预测加工表面质量,还可以对加工条件如进给速度、主轴转速对加工表面质量的影响进行仿真进而对加工条件进行优化。通过微结构功能表面的金刚石超精密切削加工验证试验,加工出表面粗糙度约为45 nm、形状精度约为0.65 µm的正弦波微结构功能表面,试验结果表明,该模型的建立对于微结构功能表面的金刚石超精密加工具有重要的指导意义。     

Characteristics of the surfaces obtained in electro-discharge machining

According to the established thermal theories on electro-discharge machining (edm), the size of the craters produced in edm is proportional to the discharge energy, which is equal to the product of mean pulse current and pulse duration for a constant gap voltage. As a practical edm surface is a random superposition of such craters, the behaviour of the surfaces largely depends on the two important parameters, pulse current and pulse duration. With the help of multiple linear regression analysis, the effect of pulse duration and pulse current on the surface topography parameters R_q and β* has been studied. sem photomicrographs have been taken in support of the qualitative evidence     

KDP晶体单点金刚石超精密切削加工的发展

总结了KDP晶体材料优异的光学性能及其难加工的机械物理特性,并回顾了KDP晶体单点金刚石切削(SPDT)加工的起源,特别对KDP晶体SPDT加工技术的国内外发展状况做了着重介绍,最后展望了KDP晶体SPDT加工的未来发展趋势。     

Super-precision cylindrical machining

A study has been made of the theory and techniques of turning precise circular components. The possibility of such high accuracy cylindrical machining was analysed according to the principle of making a precise circle. In the study, a form of chucking-type preciison cylindrical machining was developed by combining an insensitive vibration cutting mechanism - using a main spindle system which features an air bearing - with superposition superfinishing. In the first process, the work is chucked on the main spindle and machined using a continuously and systematically pulsating cutting force. In the second process, the work is finished by a newly developed superposition superfinishing device which features equivalent grades of ultrasonic vibration stone. Key points of the techniques are a torsional vibration mode tool for producing accurate, high amplitude vibration of the cutting point, and a contrivance for making accurate movements of the superposition superfinishing device. Machined roundness of 0.1–0.2 μm and surface roughness of 0.03–0.09 μm R_max were obtained with plain carbon steels, stainless steels and hardened steels (H_RC 41, 53, 60). It is considered that turning to roundness ≈ 0, cylindricity ≈ 0 and surface roughness ≈ 0 can be realized by means of this new machining process and its lathe.     

混粉电火花技术在粗加工中的应用研究

在对混粉电火花加工机理进行系统研究的基础上 ,对混粉电火花在粗加工中的加工效率和加工表面粗糙度进行实验研究。结果表明 ,通过合理选择放电参数 ,混粉电火花在相近加工表面粗糙度下 ,能够显著提高加工效率 ,从而为混粉电火花加工技术在粗加工中应用提供依据     

A digital system for surface roughness analysis of plane and cylindrical parts

This paper describes an on-line system for digital analysis of surfaces where the electrical signal from a surface roughness instrument is converted and input into a desk-top computer which also controls the traversing. Special fixtures integrated with the system and dedicated software permit two- and three-dimensional tracings to be carried out on plane as well as on cylindrical parts. The surface profiles can be plotted in different ways. Roughness parameters, frequency spectra etc, can be computed digitally and all results can be stored. Scratches and irregularities on the surface can be identified and processed separately from the rest of the surface. The desk-top computer is connected to the university mainframe computer through a modem, this being of advantage in connection with graphic data processing. The capability of the equipment has been investigated and results from calibration are presented.     

单点金刚石切削加工表面粗糙度的影响因素分析

本文研究了单点金刚石切削加工表面微观形貌形成机理,建立了圆弧刃金刚石刀具超精密加工表面微观形貌的理论模型,重点分析了主轴转速、进给量、刀尖圆弧半径和振动等因素对超精密加工表面粗糙度的影响。     

金刚石厚膜刀具切削性能的研究

制备了机夹式金刚石厚膜刀具 ,通过切削试验研究了金刚石厚膜刀具精密车削LY12铝合金时切削用量 (进给速度vf、切削速度v和切削深度ap)对切削表面粗糙度的影响     

在WC-TiC-Co硬质合金基体上制备金刚石薄膜的试验研究

通过采用Cu/Ti复合过渡层在WC TiC Co硬质合金基体上制备金刚石薄膜的试验 ,研究了沉积工艺对金刚石薄膜的质量、表面粗糙度及附着力的影响。研究结果表明 ,采用Cu/Ti复合过渡层有利于提高金刚石薄膜的附着力 ;适当降低沉积温度虽然会导致金刚石薄膜中非金刚石碳含量增加 ,但有利于增强膜层附着力。     

A study on surface roughness in ion-beam machining

This paper presents results on the influence of various machining conditions, namely machining time, (argon) ion energy, ion current density and beam angle, on surface roughness and machining depth for a high chromium — high carbon steel (SKD-1). The roughness characteristics are discussed from the measurement of surface asperities and the analysis of chromium density. In addition, as a method to obtain good surface roughness, the floating method which applies a positive charge to the workpiece, is tested.     

金刚石刀具高速精密切削加工的研究

采用聚晶金刚石刀具和天然金刚石刀具对LY12高强度铝合金进行了高速精密切削试验 ,系统研究了切削条件、切削用量对加工表面粗糙度的影响规律。结果表明 ,在比常用切削速度高 8倍的高速切削速度范围内(v=80 0～ 12 0 0m/min) ,采用圆弧刃天然金刚石刀具可获得Ra0 0 4～ 0 0 6 μm的高光洁加工表面 ;采用直线刃聚晶金刚石刀具可获得Ra0 0 7～ 0 1μm的光洁加工表面。切削速度对加工表面粗糙度的影响主要受到机床动态特性的制约 ;进给量的选择范围较大 ;背吃刀量对加工表面质量影响极大 ,为获得较小表面粗糙度必须合理选用背吃刀量     

金刚石飞切加工微结构表面的工艺参数优化

为了获得具有纳米级表面质量的微结构表面,利用‘Nanosys-300'超精密复合加工系统实现了微结构表面的三维金刚石飞切加工,研究了主轴转速、进给量以及背吃刀量对微结构表面粗糙度的影响.理论分析表明,金刚石飞切加工微结构时理论表面粗糙度沿法线方向并没有变化,而沿进给方向存在着周期变化.减小进给量和金刚石飞刀前端角或增大切削半径可以降低理论粗糙度值.实验分析表明,表面粗糙度值Ra随进给量的增加而增加,主轴转速对Ra影响不大.切削聚碳酸酯(PC)时,在5～40 μm Ra随背吃刀量的增加而增加;而切削铝合金(LY12)时,在2～10 μm Ra随背吃刀量的增加而减小.实验中Ra最好可达38 nm(LY12)和43 nm(PC).最后,利用优化工艺参数加工出了微沟槽阵列和微金字塔矩阵微结构.