The statistical modeling of surface roughness in high-speed flat end milling

Surface roughness is one of the most important requirements in machining process. The surface roughness value is a result of the tool wear. When tool wear increase, the surface roughness also increases. The determination of the sufficient cutting parameters is a very important process obtained by means of both minimum surface roughness values and long tool life. The statistical models were developed to predict the surface roughness.This paper presents the development of a statistical model for surface roughness estimation in a high-speed flat end milling process under wet cutting conditions, using machining variables such as spindle speed, feed rate, depth of cut, and step over. First- and second-order models were developed using experimental results of a rotatable central composite design, and assessed by means of various statistical tests. The highest coefficient of correlation (R_adj²) (88%) was obtained with a 10-parameter second-order model. Meanwhile, a time trend was observed in residual values between model predictions and experimental data, reflecting the probable effect of the tool wear on surface roughness. Thus, in order to enhance the estimation capability of the model, another independent variable was included into the model to account for the effect of the tool wear, and the total operating time of the tool was selected as the most suitable variable for this purpose. By inserting this new variable as a linear term into the model, R_adj² was increased to 94% and a good fit was observed between the model predictions and supplementary experimental data.In this study, it was observed that, the order of significance of the main variables is as X₅>X₃>X₄>X₁>X₂ (total machining time, depth of cut, step over, spindle speed and feed rate, respectively).     

数控机床主轴位置自动测量的实现

论述了数控机床主轴的结构以及数控机床主轴位王的测量电路的设计，实现了数控机床主轴位王参数的自动化测量过程。     

Novel methods for rapid assessment of tool performance in milling

The paper examines the effectiveness of two innovative techniques designed to rapidly optimize a milling application. One of them relates to quantifying the relative wear of different insert grades concurrently in a single cutting test, by mounting the inserts in the same cutter, for a quick comparative performance evaluation. Experimental results that illustrate the validity and limitation of this concept, and a scheme for enhancing the reliability of the test method are presented. The other technique refers to rapid identification of the optimum feed/tooth that corresponds to maximum tool life. This entails a test wherein individual inserts in the cutter are subject to feed/tooth that are multiples of a base value, by selectively leaving appropriate number of consecutive insert pockets unoccupied. These novel techniques complement known accelerated tool life tests, and are expedient for industries that engage short production runs, in terms of selecting a suitable insert grade for an application, and determining optimal cutting conditions for the selected grade.     

基于机器视觉的加工刀具磨损监测方法

为了对加工过程中刀具的磨损状态进行监测,针对麻花钻的磨损形式,提出基于机器视觉的加工刀具磨损监测方法. 根据磨损刀具图像的灰度分布特点,提出基于积分图加速和Turky bi-weight核函数的非局部均值去噪方法;采用单、双阈值大津法获取磨损区域的灰度区间,实现对图像的自适应对比度增强;提出基于形态学重构方法的磨损区域局部极值点提取方法,有效完成对磨损区域的检测和边界提取. 该刀具磨损检测方法成功应用于麻花钻头磨损状态的监测过程,实验结果表明,相较于目前已有的机器视觉监测方法,所提出的方法具有更高的检测精度和效率,准确地提取磨损轮廓,从而有效实现对刀具磨损状态的监测和自动化监控加工过程,达到降低人工成本和产品不合格率的目的.     

数控机床热误差的时序分析法建模及其应用

提出了采用时间序列分析法进行机床热误差建模的基本原理及方法,及其在数控机床热误差补偿建模中的应用。利用实测的热误差序列进行时序分析识模、建模和预报。再通过由微机结合机床控制器构成的补偿系统,利用所建立的时序分析模型,经过微机算出补偿值并送入机床控制器对刀架进行附加进给运动完成实时补偿。实验结果表明,可将工件的尺寸变化从原来的25 μm以上降到10 μm以内,大幅度提高了机床的加工精度,从而论证了时序分析法在数控机床热误差建模应用中的可行性与有效性。     

TiCN基硬质合金刀具切削性能与切削机理研究

通过系统地切削试验，研究了TiCN基新型硬质合金刀具在耐磨性、抗冲击性、切削力、刀一屑摩擦系数、加工表面质量等方面的切削性能特点；并通过一定的理论分析，探讨了TiCN基硬质合金综合性能优越的切削机理。研究所得大量切削试验数据及回归经验公式等，可供TiCN基硬质合金刀具推广应用时参考。     

Accuracy test of five-axis CNC machine tool with 3D probe–ball. Part I: design and modeling

The error model of CNC machine tool describes the relationship between the individual error source and its effects on the overall position errors. A practical problem in applying this technique to five-axis machine tool is that the predicted position errors cannot be justified. This paper, the first in a set of two, presents a new measurement device, the probe–ball, which can be used to measure the overall position errors of five-axis machine tools directly. To perform the accuracy test, a three-degree-of-freedom (3D) measuring probe is installed in the main spindle and a base plate is fixed on the turntable. The kinematic chain of the five-axis machine tool is then closed through connecting the central ball on the base plate with the extension bar of the probe. To generate simultaneous axes motion under the condition of closed kinematic chain, the central ball is defined as origin of the workpiece coordinate frame and the probe is driven along a path on a spherical test surface with the central ball as center. The overall position errors are measured with the 3D measuring probe. A theoretical model is derived to explain the nature of the probe–ball error measurements.     

晶闸管式等离子弧切割机的使用与维修

本文介绍了晶闸管式等离子弧切割机的操作原理、使用和维修技术。     

基于FANUC数控系统实现刀具寿命管理

文章结合HARDINGE数控车床实例，介绍了如何利用FANUC18T数控系统中提供的计数器跟踪刀具加工的次数，通过新增一个刀具寿命管理功能模块的PMC子程序，为用户提供一个友好、可视、便捷的刀具寿命管理功能。对今后类似的设备功能设计和改进都具有实际的指导意义和参考价值。     

用圆柱铣刀加工带冠弯扭叶片

本文把微分几何中曲线与曲面之间的“切触”概念应用于叶片复杂曲面的数控加工，提出用圆柱铣刀的外圆在五坐标联动中加工小曲率曲面的最佳切触条件。