基于不同铣削方式的球头铣刀切削性能的研究

利用Third Wave Advant Edge软件针对球头铣刀的平面和斜面铣削建立铣削模型,采用单因素的方法对球头铣刀铣削7075-T6进行有限元仿真试验,得到铣削力和铣削温度在不同铣削方式下随转速、进给量及切削深度变化的规律,为球头铣刀铣削7075-T6的铣削方式和铣削参数的合理选择提供依据。     

球头铣刀铣削轮廓曲面的有效切削速度分析

对球头铣刀加工轮廓曲面的有效速度进行研究,考虑到球头铣刀倾角变化和工件曲率半径变化,建立了球头铣刀切削凹凸轮廓曲面的干涉模型。采用相对加工倾角的方式解决了高角度铣削的干涉问题,并根据实际有效切削直径得到凹凸轮廓曲面的有效切削速度。研究结果表明:采用小切入角度和大切出角度切削加工曲面时,有效切削速度较小;铣削加工凹曲面时受切深影响较大,凸曲面主要受前后刀轨影响较大。     

小直径铣刀高速铣削淬硬模具钢不同走刀方式下切削力和加工效率的研究

高速加工是制造技术的一次革命性变革,是当今机械加工技术不可抗拒的发展潮流.小直径铣刀高速加工硬质模具钢时不同的切削条件及切削方式又是影响切削力的重要因素之一.本文主要研究刀具以不同走刀方式,在圆弧拐角处改变不同的进给速度铣削淬硬钢带岛屿的型腔时对切削力、及加工时间的影响情况,从而得出在同样的切削条件下摆线式走刀时刀具所受到的切削力较小,但是其加工效率也较低,相比之下圆弧走刀时刀具所受到的切削力较大而切削效率却较高的结论.故在高速加工时从保护刀具的角度出发易选用摆线走刀方式.     

曲面铣削过程加工路径对切削力和磨损的影响研究

针对不同走刀路径下的复杂曲面加工过程进行球头铣刀铣削Cr12MoV加工复杂曲面研究,分析不同走刀路径下铣削力和刀具磨损的变化趋势。试验结果表明:通过对比分析直线铣削和曲面铣削过程中的最大未变形切屑厚度,可以得出单周期内曲面铣削的力大于直线铣削过程的力,铣削相同铣削层时环形走刀测得的切削力普遍大于往复走刀测得的切削力;以最小刀具磨损为优化目标,运用方差分析法分析得出不同走刀路径的影响刀具磨损的主次因素,同时利用残差分析方法建立球头铣刀加工复杂曲面刀具磨损预测模型,并通过试验进行验证。     

角度铣刀切削力学性能研究

针对角度铣刀结构设计及切削寿命等问题,对角度铣刀切削过程的力学性能进行了研究。依据刀具设计原则对角度铣刀进行了结构设计,以斜角切削理论为基础,基于LS-DYNA建立了角度铣刀三维切削模型,研究了不同切削要素以及刀具几何角度对切削力的影响规律,通过与理论结果对比验证了计算模型的正确性,进而研究了不同角度铣刀的结构的切削力学性能,为角度铣刀的结构设计提供了理论基础。研究结果表明:双角角度铣刀比单角度铣刀表现出更好的切削力学性能,但其刀齿强度较弱,高速铣削时容易引起崩刃;R型刀齿的角度铣刀比尖型刀齿的角度铣刀表现出更好的切削力学性能,可将刀齿形状加工为R型。     

高速铣削难加工材料切削力建模及预测研究

针对高速加工的特点和难加工材料的组成成分、力学性能,对高速铣削难加工材料（26NiCrMoV145）的切削力进行了研究。在球头铣刀刀刃线的几何模型的基础上,采用理论分析和系数的方法,建立了螺旋刃球头铣刀的铣削力模型。对不同切削条件下的铣削力进行了仿真预测,与实验数据相吻合,证明所建立模型的正确性。     

消振指状齿轮铣刀

指状齿轮铣刀,主要用于加工大模数直齿、斜齿和人字齿轮,切削过程中,因切削刃整个长度都参与切削,所以铣削力较大。而铣刀只有一端紧固,所以它同时承受扭矩和弯矩作用。单就一个刀齿来说,由切入工件起,到旋转90°时,圆周方向切削力由零逐渐增加到最大值。当由90°旋转到180°时,圆     

TME4400I 端面铣刀

<正> 这是东芝坦葛洛伊公司新开发的不锈钢加工专用刀具,主偏角45°,轴向前角24°,径向前角—6°～—8°,是一种大刃倾角端面铣刀。这种铣刀的特点:①切削力小;②切削过程中的振动小;③切削温度低,不易产生热裂纹;④切削强度高,不易崩刃。用这种铣刀加工奥氏体不锈钢 SUS304时,切削初期和中后期,切削力均明显低于其他铣刀,能长期保持低切削力和低功耗加工。如切     

一种螺旋刃球头铣刀的高速加工铣削力模型

研究了高速加工中球头铣刀的铣削力特性。通过综合运用理论建模法和经验系数法,并引入高速切削时引起切屑动量改变所需的作用力,建立了高速切削条件下球头铣刀的铣削力模型。实验验证结果表明,理论计算值与实验测量值吻合良好。     

小直径铣刀铣削淬硬钢深窄型腔的实验研究

采用Φ2 mm TiAlN涂层硬质合金铣刀对S136淬硬模具钢的深窄型腔进行中高速干式切削实验,研究走刀方式、螺旋下刀半径、螺旋角、切削深度、切削速度、进给速度等因素对切削力和振动的影响规律,为优化小直径铣刀铣削高硬材料模具深窄型腔的工艺参数提供依据.     

Characteristics of Inclined Planes According to the Variations of Cutting Direction in High-Speed Ball-End Milling

The recent developments of the manufacturing industry require the machining of freeform surfaces using a ball-end mill. The ball-end mill is geometrically complex. For this reason, there are frequent changes of the contact point between a workpiece and a tool, which changes the machining characteristics when machining a freeform surface. In this study, a comparative evaluation of cutting characteristics will be made for a workpiece with inclined planes at angles of 15°,30°, and 45° each using four possible tool paths in down cutting. Then, tool life will be evaluated for heat-treatment materials of high hardness before obtaining the optimal tool path, which makes machining stable and improves tool life.     

Cutting force prediction in ball-end milling with inclined feed by means of geometrical analysis

A geometrical model for the analysis of cutting forces in ball-end milling has been presented in a previous work (Tsai CL, Liao YS, J Mater Process Technol 205:24–33, 10), which can be used to analyze cutting forces in vertical or horizontal feed. In this paper, the three-dimensional geometrical analysis is depicted with different interacting relations among cutting edge, undeformed chip and shear zone along nonhorizontal cutting direction, and a general geometrical model of inclined feed in ball-end milling is presented. According to the geometrical analysis, the cutting directions of horizontal, vertical, inclined downward, and inclined upward feed are defined with a feed angle. A general force model is derived, and the three-dimensional cutting forces are predicted. Experiments are conducted to verify the geometric force model. The influences of different feed angle and helix angle on cutting forces in inclined downward and inclined upward feed are discussed and simulated.     

Cutter path orientations when high-speed finish milling inclined hardened steel

The use of high-speed milling (HSM) for the production of moulds and dies is becoming more widespread. Critical aspects of the technology include cutting tools, machinability data, cutter path generation and technology. Much published information exists on cutting tools and related data (cutting speeds, feed rates, depths of cut, etc.). However, relatively little information has been published on the evaluation of cutter paths for this application. Most of the research focuses on cutter path generation with the main aim on reducing production time. Work concerning cutter path evaluation and optimisation on tool wear, tool life and relevant workpiece machinability characteristics are scant. This paper investigates and evaluates the different cutter path orientations when high-speed finish milling inclined hardened steel, at a workpiece inclination angle of 75°. The results demonstrate that employing a vertical downward orientation achieved the longest life. However, in terms of workpiece surface roughness, vertical upward orientation is generally preferred.     

Experimental study of the effect of tool orientation in five-axis micro-milling of brass using ball-end mills

The effect of tool orientation on the final surface geometry and quality in five-axis micro-milling of brass using ball-end mills is investigated. Straight grooves with a semicircular cross section are cut with different tool inclination and tilt angles, and the resulting surfaces are characterized using an optical profilometer and microscope. Micro-milling cutting forces are recorded synchronously with spindle electric current and cutting motions in order to investigate the correlation between the tool orientation and the achieved surface quality. Results of various cutting experiments and analysis of the final surface geometry show that varying the tool orientation reduces rubbing of the material at the bottom of the grooves, which often occurs in ball-end milling of brass, and improves the final surface quality. The experimental analysis for surface roughness shows that applying a tool inclination angle of 15° can considerably improve the surface roughness at the bottom of the grooves. Analysis of static and averaged peak-to-valley (P-to-V) values of the cutting forces show that the static cutting force values are reduced by half when the tool inclination was increased from 0 to 15°. P-to-V cutting force values in along-the-feed direction were also decreased in the inclined machining.     

Cutting force prediction for ball-end mills with non-horizontal and rotational cutting motions

Accurate cutting force prediction is essential to precision machining operations as cutting force is a process variable that directly relates to machining quality and efficiency. This paper presents an improved mechanistic cutting force model for multi-axis ball-end milling. Multi-axis ball-end milling is mainly used for sculptured surface machining where non-horizontal (upward and downward) and rotational cutting tool motions are common. Unlike the existing research studies, the present work attempts to explicitly consider the effect of the 3D cutting motions of the ball-end mill on the cutting forces. The main feature of the present work is thus the proposed generalized concept of characterizing the undeformed chip thickness for 3D cutter movements. The proposed concept evaluates the undeformed chip thickness of an engaged cutting element in the principal normal direction of its 3D trochoidal trajectory. This concept is unique and it leads to the first cutting force model that specifically applies to non-horizontal and rotational cutting tool motions. The resulting cutting force model has been validated experimentally with extensive verification test cuts consisting of horizontal, non-horizontal, and rotational cutting motions of a ball-end mill.     

Effects of inclination angles on geometrical features of machined surface in five-axis milling

With the development of manufacturing technology, five-axis milling has been one of the most important solution strategies in machining field. To deepen the understanding of multi-axis processing and improve the application level of the technology, the current work was carried out. This paper investigated the effects of tilt and lead angle on the scallop height, surface roughness, surface topography, and surface damages in five-axis ball-end milling process. Both geometrical analysis and experiment research are conducted to investigate the scallop height after five-axis milling, and variation of the surface roughness and surface topography with tool inclination angle obtained from the experiments was analyzed. Surface damages under the different inclination angles were also observed and analyzed with optical profiler. Several conclusions are made as follows. The inclination angles of the ball-end mill have no effect on the scallop height when only the spherical part of the cutter participates in the cutting process according to the geometrical analysis. Surface roughness with regard to tilt angles presents symmetrical characteristic around 0°. Surface texture feature, especially the texture direction, is closely related with the tool posture. The surface concave pits, convex marks, microscopic cracks, and spot corrosions are mainly the damage forms of the machined surface. More surface blemishes appeared when small inclination angles are adopted in cutting. As a result, the recommendatory inclination angle values for inclination angle are proposed. A better understanding of the five-axis machining process would be given by the detailed analysis of generation reason of the machined surface features, and the results could provide support for process parameter optimization.     

Form error estimation in ball-end milling of sculptured surface with z-level contouring tool path

This paper presents a flexible model for estimating the form error in three-axis ball-end milling of sculptured surface with z-level contouring tool path. At an interval of feed per tooth, the whole process of sculptured surface machining is treated as a combination of sequential small inclined surface milling. For ball-end milling of the inclined surface with z-level contouring tool path, at surface generation position, an analytical model is proposed to identify the feedback effect of tool deflection on cutting edge engagement. The deflection-dependent cutting edge engagement is determined by using an iterative procedure. And ultimately, the form error is obtained from the balanced tool deflection and associated surface inclination angle. In a validation experiment, the estimated form errors are compared with both the measurements and the predictions of a rigid model. It is shown that the proposed flexible model gives significant better predictions of the form error than rigid model. Good agreement between the predicted and measured form errors is demonstrated for the ball-end milling of sculptured surface with z-level contouring tool path.     

球头铣刀加工倾角对切削力的影响

对球头铣刀刀具轴线和工件加工表面之间的加工倾角进行了理论研究,建立了加工曲面时刀具倾角的数学模型,并通过试验研究了高速铣削铝合金时刀具倾角对切削力的影响规律。随着刀具轴线相对于进给方向倾斜角度β的增大,切削力变化的趋势是减小;编制多轴数控加工程序时可以通过设置合理的刀具倾角来改善切削条件。     

Design and fabrication of a new micro ball-end mill with conical flank face

Micro ball-end milling is an efficient method for the fabrication of micro lens array molds. However, it is difficult to meet the machining quality of micro dimple molds due to the wear and breakage of the milling cutter, which presents large challenges for designing geometric structure and edge strength of micro ball-end mills. In this study, a new configuration of a micro ball-end mill for micro dimple milling is designed and named the micro conical surface ball-end mill. The cutting edge is formed by intersecting the conical surface and the inclined plane. A practical grinding method is proposed based on the kinematic principle of the six-axis computer numerical control (CNC) grinding machine for micro conical surface ball-end mills and is validated by grinding simulations and experiments. Micro dimple milling experiments are conducted on the hardened die steel H13 to investigate the cutting performance of the mill. The milling force, the micro dimple roundness error, and the tool wear morphology are observed and analyzed. The results show that the radial milling force is more stable and the wear resistance is improved for the micro conical surface ball-end mill compared to the traditional micro spiral blade ball-end mill. Therefore, a more stable roundness at the entrance hole of the micro dimple can be obtained by using this design after a number of micro dimples have been milled.