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Roundness modeling of machined parts for tolerance analysis 总被引:1,自引:0,他引:1
Out-of-roundness of circular and cylindrical parts can greatly affect assembly accuracy. At present, the ASME Y14.5M-1994 specifies circularity tolerance based on two extreme circular boundaries to confine the highest peak and the lowest valley of a roundness profile; however, the profile variations within the two extreme boundaries are not accounted for. In this paper, we propose a harmonic roundness model using Fourier series expansion. In addition, a cutting profile model has been developed to illustrate the relationship between the radial error motion of a spindle and the resultant part profile. This relationship is then used to provide physical meanings to the harmonics generated by the proposed roundness model for a part profile, in particular those caused by fractional frequency spindle error motions. The proposed harmonic model has been verified statistically by a large number of real profiles produced by both turning and cylindrical grinding processes. The proposed roundness model is expected to provide insights into the advanced tolerance analysis of circular and cylindrical parts. 相似文献
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针对传统浇注式内排屑深孔钻削加工方法(BTA或DF)存在着切削液消耗量大、生产成本高、污染环境及危害操作者身体健康等问题,本文提出了将MQL技术(最小润滑技术)应用于内排屑深孔加工的方法(即亚干式深孔加工),并对MQL切削加工中切削液的作用与效果进行了分析。通过亚干式深孔钻削试验,确定出水溶性切削液具有良好的雾化效果,并且加工系统具有良好的冷却及排屑效果。针对刀具磨损较大等问题,提出了采用油液混合雾化以及低温冷风的方法,以提高刀具的润滑性和冷却效果。 相似文献
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本文介绍用国产 BTA 深孔钻头在进口奥氏体不锈钢上加工深孔的情况。文章以直径25.65mm 的钻头在不锈钢管板上加工直径25.7_(-0.10)~(+0.05)mm 的孔为例,分析了加工中出现的问题、产生问题的原因及解决办法,还介绍了刀具几何参数等问题。 相似文献
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为研究可转位浅孔钻在切削过程中的钻孔孔径误差,基于可转位浅孔钻的理论几何模型,并利用经典斜切理论得到浅孔钻的径向力、力矩关于刀片几何参数和切削参数的计算公式。选取常用切削参数组合,将计算得的径向合力及力矩作为边界条件,通过ANSYS有限元分析刀体挠度,得出相关钻孔孔径误差的理论值。利用统计学回归方法建立相应数学模型,并通过切削试验验证数学模型的精确性。基于建立的数学模型,通过调节切削参数,可预测并控制孔径误差值,实现浅孔钻在半精加工中对孔径余量的精确控制,有效拓展可转位浅孔钻的应用范围。 相似文献
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通过试验对3个切削刃BTA深孔钻削过程进行了研究,主要分析了在特定的深孔条件下切屑变形和钻削力的情况.通过对测试系统所得到的试验数据进行评估和证实,阐述了BTA深孔钻轴向力的组成和切屑变形、刀具磨损以及钻削力之间的关系.研究结果表明,钻头的内刃在切削过程中产生的切屑变形最大,3个切削刃(内刃、中间刃、外刃)的切削力和切屑变形的总体变化趋势是相同的. 相似文献
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The shaft behavior of BTA deep hole drilling tool 总被引:1,自引:0,他引:1
Jih-Hua Chin Chi-Ti Hsieh Li-Wei Lee 《International Journal of Mechanical Sciences》1996,38(5):461-482
This paper is a study on the shaft behavior of BTA deep hole drilling tool. The dynamics of tool shaft are often taken to be that of a second order lumped mass system for other cutting processes. This simplification does not apply for deep hole drilling because of its shaft length and the fact of fluid coupling. This paper constructed the general equations of motion for the pipe-like fluid conveying tool shaft of deep hole drill. The proposed general equations can be reduced to different specific forms of former works. Solutions for lateral and longitudinal motions were given. Series of experiments were designed and performed. Comparisons between theoretical and experimental results confirmed the validity of the constructed equations. The studies disclosed build the knowledge about the tool shaft and pave the way for future research concerning the correlation between the tool shaft and cutting process taking place on the cutting head. 相似文献
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振动切削深孔加工初始偏差对孔直线度误差的影响 总被引:3,自引:0,他引:3
构建了振动切削深孔加工钻杆在轴向振动、振动切削力和切削液流体力影响下的多跨动力学有限元模型。引入自由模态综合技术,将钻杆线性自由度的特征模态进行缩减,仅保留具有非线性动力特征的模态,从而可有效降低耦合系统自由度数,减小计算量。利用该缩减后的模型,研究了辅助支撑位置和加工深度与孔直线度误差的作用关系,获得了孔直线度随初始偏差量变化的规律,为大跨度振动切削深孔加工机床的精度设计和加工误差分析提供了依据。通过试验与数值计算结果的对比,验证了所提出方法的有效性与准确性。 相似文献
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针对BTA深孔加工中孔中心线容易产生偏斜的问题,用稳健优化设计理论研究了当加工条件参数变化时被加工孔直线度误差的变化情况.将稳健设计理论用于讨论BTA深孔加工时控制因素的选择,得到了控制因素的优化设计结果.通过试验证明使用稳健设计法对控制因素的分析和预测是正确的.该研究结果可为BTA深孔加工控制因素的分析和选择提供参考. 相似文献
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Hole quality and interelectrode gap dynamics during pulse current electrochemical deep hole drilling
Dayanand S. Bilgi V. K. Jain R. Shekhar Anjali V. Kulkarni 《The International Journal of Advanced Manufacturing Technology》2007,34(1-2):79-95
This paper presents the experimental investigation of pulse-current shaped-tube electrochemical deep hole drilling (PC-STED)
of nickel-based superalloy. Influence of five process variables (voltage, tool feed rate, pulse on-time, duty cycle, and bare
tip length of tool) on the responses, namely, depth-averaged radial overcut (DAROC), mass metal removal rate (MRRg) and linear metal removal rate (MRRl) have been discussed. Mathematical models have been developed to express the effects of the process parameters on DAROC,
MRRg and MRRl. The proposed model permits quantitative evaluation of the hole quality and process performance simultaneously. The results
have been confirmed for the profile of the drilled hole and MRRl obtained experimentally. In all the experiments, through holes of 26 mm depth and diameters ranging from 2.205 mm to 3.279 mm
were drilled. The results have been explained by the interelectrode gap dynamics prevailing during pulse electrochemical deep
hole drilling. Optimum parameters determined from these experiments can be used to efficiently drill high-quality deep holes
of high aspect ratio in nickel-based superalloys. 相似文献
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钛合金的切削加工性能差,其深孔钻削的技术难度更大。枪钻是深孔钻削的高效刀具,能有效解决钛合金的深孔加工问题。本文基于对钛合金材料切削性能和深孔钻削工艺的分析,通过深孔钻削试验,改进了钛合金叶片深孔钻削工艺,提高了枪钻寿命。 相似文献
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针对精密加工过程中影响圆度误差分离精度的问题,提出了一种基于几何动态模型的圆度误差分离模拟方法。在主轴空间运动规律的基础上,通过回转体轴心的自转和公转关系建立工件截面的几何模拟动态模型。结合三点法圆度误差分离技术实现了动态条件下的圆度误差准确表示,并分析研究了传感器安装角度与干扰误差对圆度误差分离精度的影响。数值实验分析表明,建立的几何模型分析有利于研究回转加工中圆度误差分离结果的正确性,达到了提高误差分离精度及抑制误差对加工精度影响的目的。 相似文献
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用车床加工深孔的方法与装置 总被引:1,自引:0,他引:1
介绍了基于BTA原理设计的深孔钻加工装置,解决了钻头的定位和导向难题;通过不同的方案组合,可以在板料、箱体和轴类零件上加工直径16~40mm、深径比在100以内的深孔。该装置结构简单,可方便地安装在普通车床上使用。 相似文献
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Sıtkı Akıncıoğlu Faruk Mendi Adem Çiçek Gülşah Akıncıoğlu 《The International Journal of Advanced Manufacturing Technology》2013,68(1-4):197-207
This paper focuses on artificial neural network (ANN)-based modeling of surface and hole quality in drilling of AISI D2 cold work tool steel with uncoated titanium nitride (TiN) and titanium aluminum nitride (TiAlN) monolayer- and TiAlN/TiN multilayer-coated-cemented carbide drills. A number of drilling experiments were conducted at all combinations of different cutting speeds (50, 55, 60, and 65 m/min) and feed rates (0.063 and 0.08 mm/rev) to obtain training and testing data. The experimental results showed that the surface roughness (Ra) and roundness error (Re) values were obtained with the TiN monolayer- and TiAlN/TiN multilayer-coated drills, respectively. Using some of the experimental data in training stage, an ANN model was developed. To evaluate the performance of the developed ANN model, ANN predictions were compared with the experimental results. It was found that the determination coefficient values are more than 0.99 for both training and test data. Root mean square error and mean error percentage values were very low. ANN results showed that ANN can be used as an effective modeling technique in accurate prediction of the Ra and Re. 相似文献