共查询到20条相似文献,搜索用时 31 毫秒
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K. V. R. Subrahmanyam Wong Yoke San Hong Geok Soon Huang Sheng 《The International Journal of Advanced Manufacturing Technology》2010,48(1-4):23-32
Ball nose milling of complex surfaces is common in the die/mould and aerospace industries. A significant influential factor in complex surface machining by ball nose milling for part accuracy and tool life is the cutting force. There has been little research on cutting force model for ball nose milling on inclined planes. Using such a model ,and by considering the inclination of the tangential plane at the point of contact of the ball nose model, it is possible to predict the cutting force at the particular cutting contact point of the ball nose cutter on a sculptured surface. Hence, this paper presents a cutting force model for ball nose milling on inclined planes for given cutting conditions assuming a fresh or sharp cutter. The development of the cutting force model involves the determination of two associated coefficients: cutting and edge coefficients for a given tool and workpiece combination. A method is proposed for the determination of the coefficients using the inclined plane milling data. The geometry for chip thickness is considered based on inclined surface machining with overlapping of previous pass. The average and maximum cutting forces are considered. These two forces have been observed to be more dominating force-based parameters or features with high correlation with tool wear. The developed cutting force model is verified for various cutting conditions. 相似文献
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Z. C. Wei M. J. Wang Y. J. Cai J. N. Zhu L. Wang 《The International Journal of Advanced Manufacturing Technology》2013,65(1-4):363-369
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. 相似文献
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Shi Wu Lin Yang Xian-li Liu Min-li Zheng Rong-yi Li 《The International Journal of Advanced Manufacturing Technology》2017,89(9-12):2649-2662
In this paper, a predictive model of milling stability, which considers the surface curvature and the lead angle of the milling cutter, is proposed for milling of the panel die with sculptured surface. Firstly, influences of the radius of curvature and lead angle of milling cutter on uncut chip thickness are analyzed by exploring the curvature characteristics of sculptured surface. Subsequently, influence of the curvature characteristics of sculptured surface on chatter stability lobes in milling process is investigated by utilizing the full-discretization method. This analysis implies that the milling stability decreases with the increase in the radius of the die surface’s curvature; the milling stability decreases with the increase in lead angle. The experimental results demonstrate that the prediction of chatter stability lobes could match well with the measured results on the change trend, where the maximum relative percent error is less than 11.1 % in stable milling. It is further validated that this method can effectively predict the chatter stability lobes of the domain in ball end milling of sculptured surface of die. 相似文献
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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。 相似文献
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针对高速铣削加工的切削载荷控制问题,提出一种适用于平头立铣刀2.5维铣削加工,考虑切削载荷的余量规划策略——恒力余量。通过加工试验证实了该策略的有效性,并讨论了走刀方向、刀触点轨迹线的连续性、刀具浸入包角和刀具半径对恒力余量规划结果的影响。与传统的几何等距余量规划方法相比,恒力余量策略能够显著改善切削载荷的波动情况,避免切削载荷的突变,为控制铣削载荷提供有效途径。 相似文献
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Eyyup Aras Abdulmohsen Albedah 《The International Journal of Advanced Manufacturing Technology》2014,73(9-12):1351-1362
Predicting cutting forces in milling process simulation requires finding cutter/workpiece engagements (CWEs). The calculation of these engagements is challenging due to the complicated and changing intersection geometry between the cutter and the in-process workpiece. In this paper, a solid modeling based methodology for finding CWEs generated in five-axis milling of free form surfaces is presented. The proposed methodology is an extension of the solid modeler based three-axis CWE extraction method given in [21]. At any given instant of the five-axis tool motion, the velocity vectors along the cutter axis may move in directions that do not lie in the same plane, and therefore the cutter envelopes need to be approximated by spline surfaces. Considering the spline surface approximations, the CWE methodology described in [21] does not work properly for the five-axis milling. Therefore in the proposed method, the in-process workpiece is used instead of the removal volume for extracting the CWEs. A terminology the feasible contact surfaces (FCS), defined by the envelope boundaries, is introduced. To extract the CWEs at a given cutter location, first the BODY entity, obtained by offsetting the FCS with an infinitesimal amount, is intersected with the in-process workpiece. Then, the resultant removal volume is decomposed into faces. Finally, the surface/surface intersections are performed between those faces and the FCS to obtain the CWE boundaries. To be used in the force model, the CWE boundaries are mapped from Euclidean 3D space to a parametric space defined by the engagement angle and the depth-of-cut for a given tool geometry. 相似文献
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The cutting force prediction is essential to optimize the process parameters of machining such as feed rate optimization, etc. Due to the significant influences of the runout effect on cutting force variation in milling process, it is necessary to incorporate the cutter runout parameters into the prediction model of cutting forces. However, the determination of cutter runout parameters is still a challenge task until now. In this paper, cutting process geometry models, such as uncut chip thickness and pitch angle, are established based on the true trajectory of the cutting edge considering the cutter runout effect. A new algorithm is then presented to compute the cutter runout parameters for flat-end mill utilizing the sampled data of cutting forces and derived process geometry parameters. Further, three-axis and five-axis milling experiments were conducted on a machining centre, and resulting cutting forces were sampled by a three-component dynamometer. After computing the corresponding cutter runout parameters, cutter forces are simulated embracing the cutter runout parameters obtained from the proposed algorithm. The predicted cutting forces show good agreements with the sampled data both in magnitude and shape, which validates the feasibility and effectivity of the proposed new algorithm of determining cutter runout parameters and the new way to accurately predict cutting forces. The proposed method for computing the cutter runout parameters provides the significant references for the cutting force prediction in the cutting process. 相似文献
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In high-speed ball end milling, cutting forces influence machinability, dimensional accuracy, tool failure, tool deflection, machine tool chatter, vibration, etc. Thus, an accurate prediction of cutting forces before actual machining is essential for a good insight into the process to produce good quality machined parts. In this article, an attempt has been made to determine specific cutting force coefficients in ball end milling based on a linear mechanistic model at a higher range of rotational speeds. The force coefficients have been determined based on average cutting force. Cutting force in one revolution of the cutter was recorded to avoid the cutter run-out condition (radial). Milling experiments have been conducted on aluminum alloy of grade Al2014-T6 at different spindle speeds and feeds. Thus, the dependence of specific cutting force coefficients on cutting speeds has been studied and analyzed. It is found that specific cutting force coefficients change with change in rotational speed while keeping other cutting parameters unchanged. Hence, simulated cutting forces at higher range of rotational speed might have considerable errors if specific cutting force coefficients evaluated at lower rotational speed are used. The specific cutting force coefficients obtained analytically have been validated through experiments. 相似文献
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借助建立的铣刀切削力、扭矩和切削功率的计算机预报模型 ,对平前刀面球头铣刀的切削性能进行了数值仿真研究 ;通过分析各种切削参数对切削性能的影响规律 ,获得了不同切削条件下球头铣刀切削力和扭矩的特征和变化趋势 相似文献
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利用球头铣刀高速铣削Cr12模具钢,研究了切削速度、进给量和切削深度对主轴和刀具切削振动的影响变化规律,结果表明随着切削速度的增加,工件振动增加缓慢,而主轴的振动迅速增加,远超过工件的振动成为主振动,主轴进给方向的振动要小于非进给方向的振动。在小进给时,随着进给速度增加各向切削振动而迅速下降,在大进给速度时,各向振动随进给速度增加保持平稳;各通道的切削振动都随着切削深度的增大而增长,因此在高速铣削过程中,主轴振动为主振动,是影响加工表面质量的主要因素。 相似文献
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基于正向杜邦指标线的五坐标侧铣加工 总被引:2,自引:0,他引:2
为实现叶轮类零件的多坐标侧铣加工,通过引入正向杜邦指标线,利用鼓锥形刀对自由曲面的五坐标侧铣加工进行研究。针对具有严格凸切削刃的侧铣加工刀具,提出不发生局部干涉的充要条件是切触点处刀具曲面的正向杜邦指标线位于被加工曲面的正向杜邦指标线之内。给出利用鼓锥形刀侧铣加工自由曲面时实施干涉检查的判断准则以及消除干涉的修正方法,推导出具有严格凸切削刃的刀具在给定的残留高度下侧铣加工带宽的计算方法。在此基础上,利用等残留高度法实现鼓锥形刀侧铣加工自由曲面无干涉刀具轨迹的生成。算例表明,在相同残留高度下,鼓锥形刀侧铣较之球头刀加工效率提高37.44%,说明侧铣加工是提高切削效率和加工质量的一种有效途径。 相似文献
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虚拟制造中基于刀具变形的复杂曲面加工误差预报 总被引:1,自引:0,他引:1
复杂曲面加工过程中刀具的弹性变形是产生曲面加工误差的重要原始误差。着重研究了虚拟制造环境下基于球面铣刀弹性变形的曲面加工误差预报模型。研究并建立了球面铣刀加工复杂曲面的切削力模型和刀具弹性变形模型,在此基础上,分析了曲面生成机理,提出了利用曲面变形敏感系数建立刀具弹性变形对法向加工误差的影响关系。利用该模型可以在实际切削加工前对曲面加工误差进行预报,用以进行误差补偿或切削参数优化。最后,以二维半圆形拉伸曲面为例通过切削实验对本文提出的模型进行了验证。 相似文献
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切削力预测是制定与优化加工工艺的重要环节。针对曲线端铣加工过程,提出一种基于斜角切削的切削力建模方法。将刀具沿轴向微分,以曲线微分几何计算微元刃上的工作基面。在微元刃的工作法平面参考系中,应用最小能量原理,构建微元刃中力矢量、速度矢量、流屑角、法向摩擦角、法向剪切角及剪应力等切削参数之间的约束。以单齿直线铣削试验对切削参数进行标定,其中法向摩擦角、法向剪切角及剪应力等可表示为瞬时未变形切屑厚度的函数。选取高强度钢PCrNi3MoVA试件,分别进行圆弧和Bézier曲线端铣加工试验。试验结果表明,曲线端铣时切削力的变化与瞬时进给方向和曲线曲率相关。切削力预测值的幅值大小和变化趋势与试验值一致,验证了该切削力建模方法的有效性。 相似文献
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M. H. Sadeghi H. Haghighat M. A. Elbestawi 《The International Journal of Advanced Manufacturing Technology》2003,22(11-12):775-785
A system for geometric and physical simulation of the ball-end milling process using solid modeling is presented in this paper. A commercially available geometric engine is used to represent the cutting edge, cutter and updated part. The ball-end mill cutter modeled in this study is an insert type ball-end mill and the cutting edge is generated by intersecting an inclined plane with the cutter ball nose. The contact face between cutter and updated part is determined from the solid model of the updated part and cutter solid model. To determine cutting edge engagement for each tool rotational step, the intersections between the cutting edge with boundary of the contact face are determined. The engaged portion of the cutting edge for each tool rotational step is divided into small differential oblique cutting edge segments. Friction, shear angles and shear stresses are identified from orthogonal cutting data base available in the open literature. For each tool rotational position, the cutting force components are calculated by summing up the differential cutting forces. The instantaneous dynamic chip thickness is computed by summing up the rigid chip thickness, the tool deflection and the undulations left from the previous tooth, and then the dynamic cutting forces are obtained. For calculating the ploughing forces, Wu's model is extended to the ball-end milling process [21]. The total forces, including the cutting and ploughing forces, are applied to the structural vibratory model of the system and the dynamic deflections at the tool tip are predicted. The developed system is verified experimentally for various up-hill and down-hill angles. 相似文献
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Dr S. Bedi F. Ismail M. J. Mahjoob Y. Chen 《The International Journal of Advanced Manufacturing Technology》1997,13(5):326-332
This paper compares the surface roughness along and across the feed directions produced by toroidal, ball nose, and flat bottom end mills. The study is conducted numerically and by cutting tests of aluminium. The results show that the toroidal cutter inherits the merits of the other two cutters; it produces small scallops across the feed direction, and low roughness along the feed direction.Nomenclature
h
scallop height
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R
s
radius of curvature of surface
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inclination angle
- 2a
c
cross-feed
- 2
subtended angle between the point of contact on the tool profile and the surface
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R
a
surface roughness
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e
offset distance of insert from tool axes for toroidal cutter
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r
c
cutter radius
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r
i
radius of insert for toroidal cutter
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f
t
feed per tooth
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h
u
undercut height
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y, ,
intermediate variables 相似文献
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B. Lotfi Z. W. Zhong L. P. Khoo 《The International Journal of Advanced Manufacturing Technology》2009,43(9-10):872-882
This paper proposes a new approach to predicting cutting forces in milling operations. The approach attempts to find the analytic relationship between cutting forces and the tangential direction of the tool path when a tool moves along an analytical curve, i.e., a Pythagorean-hodograph curve that describes a group of analytic curves with special properties, in a milling operation. In conventional methods for the prediction of cutting forces in milling operations, cutting forces are estimated by considering such cutting parameters as feed rate, depth of cut, and tool geometry. However, the change in the moving direction of the cutter, which has a major effect on cutting forces, is often neglected by previous researchers. This work aims to establish the theoretical basis to show how cutting forces along a curve can be predicted. Two case studies are used to illustrate the proposed cutting force prediction strategy. 相似文献