虚拟数控车削物理仿真系统的研究与开发

面向数控车削，开发了一套动态车削物理仿真系统，提仿真系统的总体框架，建立了动态物理仿真模型及相关子模型，分析了动态车削过程的影响因素，阐述了系统开发过程中有关模型构成及工件数据描述等技术性问题。     

铝合金A357车削加工工件表面温度场研究

针对铝合金车削加工过程中工件表面温度难以准确测量和精准控制的问题,基于有限元软件建立铝合金A357的二维切削仿真模型;通过切削仿真分析得出不同切削速度和切深下的工件表面温度场分布规律;设计一种用于车削加工过程中在线测量工件表面温度的实验装置;通过车削实验,得到了切削过程中工件表面温度变化趋势。结果表明：该切削仿真模型可以有效地预测工件表面温度,为进一步分析精加工工件尺寸偏差、提高工件加工表面质量提供参考依据。     

基于动态切削过程仿真的外圆车削稳定性判定

建立考虑工件轴向和径向两个方向刀具刃倾角和模态方向的车削颤振模型。利用试验得到的切削力系数和模态参数,获得给定机床、刀具和工件组合下的颤振稳定域曲线。建立外圆车削轴类零件的动力学模型,主要包括刀具相对工件的动态切削力和动态位移模型。提出一种借助动态切削力和刀具动态位移时域仿真,以及相邻两转的切削力和位移动态成分映射截面来综合判断切削过程稳定性的方法。通过切削试验验证颤振稳定域判据和动态切削过程判据的准确性。利用该方法了解稳定切削和颤振切削的信号特点和分布规律。对比颤振稳定域和动态切削仿真两种稳定性判据的有效性、优缺点和适用场合,尤其通过典型零件的切削过程仿真说明动态切削仿真方法的优点。此外,还通过对动态切削过程的变模态参数仿真,分析模态参数对切削过程稳定性的影响。     

超精密车削下刀具相对振动的辨识

在金刚石超精密车削加工中,刀具与工件之间不可避免地存在一定的振动, 从而影响工件表面质量.本文对在具有振动情况下工件表面的三维形貌进行了仿真,并从理论上对工件表面形貌的径向、周向与刀具螺旋轨迹方向的截面轮廓进行了分析,结果表明不同的截面具有不同的信息特征,并据此对仿真得到的工件表面三维形貌数据进行了振动辨识.     

数控车削加工仿真研究

基于四边形网格的离散方法,通过VC 和OpenGL,实现了车削加工过程动态仿真,重点讨论了车削毛坯的离散化以及离散节点的数据处理.为了提高图形真实感,分析了车削毛坯离散节点的法向量求解方法和车削工件的绘制方法;针对螺纹车削加工的特殊性,介绍了螺纹的几何和行为建模方法.实践表明,上述方法可以实现车削加工过程实时仿真,获得较好的真实感效果.     

高真感虚拟车削加工系统中工件模型的建立

提出对虚拟车削加工中工件物理信息处理的问题，使用扫描体方法实现了实时虚拟加工。同时提出了工件的形状误差和表面误差模型以及切屑生成模型。此方法实现了虚拟车削的高真感仿真，克服了以往的代码校验软件中无工件物理信息和工件的成品信息的缺陷，同时增强了软件的沉浸感。     

微小窄槽的数控车削加工技术研究

以微小窄槽为研究对象,介绍了内型芯工件结构特点,从车削振动和锥度、微小窄槽车削、车削表面质量及编程效率等方面分析了工件的加工难点。编制了合理的数控车削加工工艺,设计了基于分离式可换刀头结构的微小窄槽专用车刀,在保证刀具刚性的情况下,通过三因素正交试验,确定了刀具的几何角度,并完成了专用车刀的制作。选用了合理的切削液,改善了已加工面的表面质量。运用宏程序方法进行高效数控编程,简化了加工程序,提高了生产效率。     

细长导辊超声车削的试验研究

怎样提高细长轴车削表面质量 ,一直是机械制造生产中的难题之一 ,该问题在不锈钢细长导辊的车削过程中显得尤为突出。利用超声振动车削方式 ,对细长不锈钢导辊进行车削试验研究 ,探讨了切削速度、进给量、切削深度以及刀尖振幅对工件表面粗糙度的影响。     

虚拟加工系统研制与加工误差分析

面向数控车削加工过程研制了一个虚拟数控加工系统。该系统以Windows2000为开发平台，以Visual C 6．0为开发工具，基于OpenGL技术实现了数控车削加工过程3维仿真。该系统能够有效地仿真数控车削过程，具有更接近实际车削加工过程的特点。同时在仿真研究中，分析了加工过程中由切削力导致的加工误差，实现了对虚拟车削工件加工误差的预测。     

车削过程切削力的计算机数值仿真

切削力是表征切削过程最重要特征的物理量,其动态变化将直接影响加工过程中刀具与工件的相对位移、刀具磨损和表面加工质量等,所以对切削力建模是进行加工过程物理仿真研究的基础。因此在基于实时工况的切削实验研究基础上,考虑切削参数的因素,利用BP（back pmpagation）神经网络建立车削过程中的切削力的仿真模型。通过大量的样本训练,使神经网络能够对切削力进行较准确地数值仿真。     

Implementation of an open-loop control technique for high-speed micropositioning in a single-point diamond turning process

An investigation is undertaken to minimize residual vibrations associated with high-speed, low-amplitude machining processes. A numerically computed input signal allows the system to follow a desired output trajectory once an accurate dynamic model of the system is developed. Specific application of this method is focused on controlling tool motion while cutting micron depth surface features into a flat, rotating workpiece during a single-point diamond turning process. The synthesized input signal, applied open-loop, is used to eliminate transient surface features that are created by uncontrolled motion of the tool when it is plunged into the workpiece surface during the cutting process. Controlled and uncontrolled cuts are shown to demonstrate a significant improvement in resulting surface features.     

Prediction of the Effect of Tool Interference on Surface Generation in Single-Point Diamond Turning

Tool interference has its origin from the small amplitude and low frequency vibration existing between the tool and the workpiece in single-point diamond turning (SPDT). It inevitably affects the surface quality of a diamond turned surface. In this paper, a surface topography simulation model is proposed for the prediction of the effect of tool interference on surface generation in SPDT. It makes use of the surface roughness profiles predicted at a finite number of equally spaced radial sections of a workpiece to construct the surface topography of a diamond turned surface. The approach overcomes the limitation of the existing theories that can check only for the existence of tool interference. The model was evaluated through practical cutting experiments. Experimental results were found to agree well with the predicted results.     

Effects of cutting edge geometry, workpiece hardness, feed rate and cutting speed on surface roughness and forces in finish turning of hardened AISI H13 steel

In this study, the effects of cutting edge geometry, workpiece hardness, feed rate and cutting speed on surface roughness and resultant forces in the finish hard turning of AISI H13 steel were experimentally investigated. Cubic boron nitrite inserts with two distinct edge preparations and through-hardened AISI H13 steel bars were used. Four-factor (hardness, edge geometry, feed rate and cutting speed) two-level fractional experiments were conducted and statistical analysis of variance was performed. During hard turning experiments, three components of tool forces and roughness of the machined surface were measured. This study shows that the effects of workpiece hardness, cutting edge geometry, feed rate and cutting speed on surface roughness are statistically significant. The effects of two-factor interactions of the edge geometry and the workpiece hardness, the edge geometry and the feed rate, and the cutting speed and feed rate also appeared to be important. Especially honed edge geometry and lower workpiece surface hardness resulted in better surface roughness. Cutting-edge geometry, workpiece hardness and cutting speed are found to be affecting force components. The lower workpiece surface hardness and honed edge geometry resulted in lower tangential and radial forces.     

车削加工中提高金属表面粗糙度的研究

以实际生产中遇到的几类难以达到加工精度的具体问题为研究对象，通过使用几种专门设计制造的刀具，利用常规的加工工艺，经过大量试验，得出几种提高产品零件表面粗糙度的工艺措施，对其做了较为详尽的分析与论述。     

超精密加工的三维表面形貌预测

描述并建立了仿真超精密加工的三维表面形貌模型。三维表面形貌模型由切削参数,刀具几何形状及刀具与工件的相对运动来表征,通过将预测的表面粗糙度轮廓线性映射到网格 面元上来生成已加工表面的形貌,实际的加工和测量实验表明,仿真的三维表面形貌和由激光干涉形貌仪测量得到的三维形貌具有很好的相似性。该模型可用来确定如刀具切削运动的迹线,表面波度等表面特征。     

A novel force-based two-dimensional tool centre error identification method in single-point diamond turning

In single-point diamond turning (SPDT), two-dimensional (2D) tool centre error is caused by the tool deviating from the workpiece rotation centre both in the horizontal direction (tool feed direction) and vertical direction (perpendicular to tool feed direction). This greatly affects the form accuracy of the machined surface and its optical function. Traditional tool centre error identification is usually performed off-machine manually with high-precision instruments, which is time-consuming and labour-dependent. In this paper, a novel force-based 2D tool centre error identification method in SPDT is introduced. First, according to the relative position between the tool and workpiece centre, the tool centre error is classified into nine cases. The relation between the cutting force profiles and the tool centre error is analysed for each case. Then, a numerical fitting model and a geometric model are established to identify tool-above-centre and tool-below-centre errors, respectively. Additionally, a geometric model is established to calculate the normal distance from the tool interference/exit cutting to the workpiece centre, which serves as a reference for the horizontal tool centre error identification. Finally, the on-machine identification results of the 2D tool centre error are verified by experiments. Theoretical and experimental results show that the proposed on-machine 2D tool centre error identification method is effective and accurate, which greatly improves the cutting efficiency in SPDT.     

影响工件车削加工质量的因素分析

在机械加工过程中,影响工件的最终加工质量的因素有很多种.工件加工质量的高低是决定其使用性能好坏的重要因素.通过对工件车削加工质量影响因素的分析,找到如何使工件的加工达到质量技术要求的措施,既保证工件表面的加工质量,又避免增大零件的制造成本,造成不必要的损失.     

Analysis of surface roughness and cutting force components in hard turning with CBN tool: Prediction model and cutting conditions optimization

In this study, the effects of cutting speed, feed rate, workpiece hardness and depth of cut on surface roughness and cutting force components in the hard turning were experimentally investigated. AISI H11 steel was hardened to (40; 45 and 50) HRC, machined using cubic boron nitride (CBN 7020 from Sandvik Company) which is essentially made of 57% CBN and 35% TiCN. Four-factor (cutting speed, feed rate, hardness and depth of cut) and three-level fractional experiment designs completed with a statistical analysis of variance (ANOVA) were performed. Mathematical models for surface roughness and cutting force components were developed using the response surface methodology (RSM). Results show that the cutting force components are influenced principally by the depth of cut and workpiece hardness; on the other hand, both feed rate and workpiece hardness have statistical significance on surface roughness. Finally, the ranges for best cutting conditions are proposed for serial industrial production.     

金刚石车削工件表面轮廓的仿真与分析

对振动情况下加工的工件表面的三维形貌进行了仿真 ,并从理论上对工件表面形貌的径向、周向与刀具螺旋轨迹方向的截面轮廓进行了分析。结果表明 :不同的截面轮廓分别载有不同的表面特征信息 ,利用这些特征有助于对刀具与工件间的相对振动进行辨识。采用有关文献中的试验数据对仿真结果进行了验证