共查询到20条相似文献,搜索用时 15 毫秒
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B. Lauwers J.P. Kruth P. Dejonghe 《The International Journal of Advanced Manufacturing Technology》2001,17(11):799-804
Multi-axis milling of sculptured surfaces with cylindrical or toroidal cutters has many advantages compared to the use of
three-axis milling with ball nose cutters. Surfaces to be machined are often of complex shape and characterised by convex,
concave and saddle areas. Today, CAM-systems do not support the user in the selection of the different operations in order
to finish the workpiece. This paper describes an operation planning system, which facilitates process planning for the multi-axis
machining of sculptured surfaces. The core of the system is surface analysis, which divides the surfaces into regions, each
characterised by a preferred milling direction and tool diameter. Further, for each region or set of regions, a drive surface
is constructed that is used as the basis for the tool-path calculation. The drive surface approximates to the original workpiece
as closely as possible, and the isoparametric lines which will be the tool-path feed direction lie in the preferred milling
direction. 相似文献
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Y. N. Hu Y. H. Chen 《The International Journal of Advanced Manufacturing Technology》1999,15(9):624-629
Rapid prototyping plays an important role in product development. There are two ways to realise rapid rototyping: one is
to develop new prototyping equipment such as stereolithography apparatus (SLA), selective laser sintering (SLS), etc., and
the other is to improve existing CNC techniques. In this work, a robot system for rapid prototyping, which is an enhancement
of the CNC based method, is presented. A robot arm holding a milling tool is used to machine the prototype of a solid model
drawn using a commercial CAD system. In this paper, Part 1, a strategy using the robot for rough machining is discussed and
then an automatic tool-path generation method using a grid height array is presented. This method can generate tool paths
for rough machining with different tolerances. As a verification of the proposed algorithm, a number of prototypes have been
produced, which have demonstrated the feasibility and advantages of the algorithm. In a companion paper, Part 2, an approach
to represent C-space by incorporating possible variations in tooling orientations is proposed. In order to reduce error on
complex surfaces resulting from undercut or overcut operations, a curvature-matching algorithm is developed. Finally, experimental
work using the collision-free planning strategy and simulation for the curvature matching algorithm is carried out. 相似文献
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Y. N. Hu Y. H. Chen 《The International Journal of Advanced Manufacturing Technology》1999,15(9):630-639
Rapid prototyping plays an important role in product development. There are two ways to realise rapid prototyping: one is
to develop new prototyping equipment such as stereolithography apparatus (SLA), selective laser sintering (SLS), etc., and
the other is to improve existing CNC techniques. In this work, a robot system for rapid prototyping, which is an enhancement
of the CNC based method, is presented. A robot arm holding a milling tool is used to machine the prototype of a solid model
drawn using a commercial CAD system. In a previous paper, Part 1, a strategy using the robot for rough machining was discussed
and then an automatic tool-path generation method using a grid height array was presented. As a verification of the proposed
algorithm, a number of prototypes were produced, which demonstrated the feasibility and advantages of the algorithm. In this
paper, Part 2, an approach to represent C-space by incorporating possible variations in tooling orientations is proposed.
In order to reduce the error on complex surfaces resulting from undercut or overcut operations, a curvature-matching algorithm
is also developed. Finally, experimental work using collsion-free planning for manipulator movement and stimulation for the
curvature matching algorithm is carried out. 相似文献
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对自由曲面用带角圆柱铣刀3轴NC加工提出了系统的刀具干涉检测方法。加工自由曲面时,刀具干涉可以出现在包括刀具驱动面的刀具周围的任何地方。本文提出先检测自由曲面上可能产生刀具干涉的区域,然后再生成刀具路径,这样不但可极大地简化安排刀具路径的过程,改善加工的精度和可靠性,而且有利于产品的几何设计和影响加工效率的刀具选择。研究表明所提方法和算法是合理有效的。 相似文献
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铣削加工中,在精加工轮廓程序的基础上,采用改变刀具偏置量大小的方法,可进行工件轮廓的粗铣加工.通过应用FANUC系统宏程序给系统变量赋值的功能,设置刀具半径补偿,探讨了用环切的方法进行直线包络等距型面外轮廓的粗铣加工,达到简化粗铣程序,提高粗加工效率的目的. 相似文献
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针对复杂多曲面通道的多坐标数控粗加工,提出了一种新的刀具轨迹生成算法.该算法以传统的插铣加工方法为基础,提出适合于复杂多曲面通道的新插铣方法;利用曲面参数线,使用B样务曲线正算反算方法,在流道划分的多个截面上做由初始孔到截面轮廓的渐变曲线;通过计算满足残留高度的走刀行距,在各个截面的渐变曲线上提取参数点并拟合出相应曲线,进而得到刀具接触点轨迹. 相似文献
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WU Shixiong WANG Chengyong FAN Jingming 《机械工程学报(英文版)》2007,20(5):1-4
An approach is presented to generate rough interference-free tool-paths directly from massive unorganized data in rough machining that is performed by machining volumes of material in a slice-by-slice manner. Unorganized point-cloud is firstly converted to cross-section data. Then a robust data-structure named tool-path net is constructed to save tool-path data. Optimal algorithms for partitioning sub-cut-areas and computing interference-free cutter-locations are put forward. Finally the tool-paths are linked in a zigzag milling mode, which can be transformed into a traveling sales man problem. The experiment indicates optimal tool paths can be acquired, and high computation efficiency can be obtained and interference can be avoided successfully. 相似文献
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An Effective Global Gouge Detection in Tool-Path Planning for Freeform Surface Machining 总被引:1,自引:0,他引:1
L. Zhou Y.-J. Lin 《The International Journal of Advanced Manufacturing Technology》2001,18(7):461-473
This paper examines a usually neglected gouge phenomenon in tool-path planning for machining parts having freeform surfaces with 3-axis ball-end mills. That is, when a freeform surface is being milled with a ball-end cutter, a gouge may exist anywhere around the cutter circumference, in addition to the tool driving plane. A global gouge detection concept is developed to solve this problem. An effective method is proposed to identify the potential gouge areas on the sculptured surface during machining, before generating tool paths. Thus, it greatly simplifies the tool-path planning procedure and improves the accuracy and reliability of machining. It also facilitates geometric design processes of products and cutter radius selection which are crucial to machining efficiency. The designed part surfaces tested by the proposed methodology are constructed based on bicubic B2-splines and are assumed to be at least C 2 and may possess C 1 or C 0 continuity for generality. The tested examples demonstrate the effectiveness of the developed global gouge detection approach.
This revised version with a corrected online cover date was published online in April 2004. 相似文献
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分析数控车床自动编程系统中直线和圆弧刀具轨迹出现刀具干涉的条件,提出了解决刀具干涉的处理方法,给出了刀具路径验证的总体算法,实现了生成无干涉的刀具路径的功能。 相似文献
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C. Tournier E. Duc 《The International Journal of Advanced Manufacturing Technology》2002,19(5):318-324
The machining of sculptured surfaces such as moulds and dies in 3-axis milling relies on the chordal deviation, the scallop
height parameter and the planning strategy. The choice of these parameters must ensure that manufacturing surfaces respect
the geometrical specifications. The current strategies for machining, consist primarily in driving the tool in parallel planes
which generates a tightening of the tool paths. A constant scallop height planning strategy has been developed to avoid this
tightening. In this paper, we present a new method of constant scallop height tool-path generation based on the concept of
the machining surface. The concept of the machining surface is developed and its use to generate constant scallop height tool
paths is described. The approach is compared with existing methods in terms of precision and in particular its aptitude to
treat curvature discontinuities. 相似文献
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The progressive cutting based on auxiliary paths is an effective machining method for the material accumulating region inside the mould pocket. But the method is commonly based on the radial depth of cut as the control parameter, further more there is no more appropriate adjustment and control approach. The end-users often fail to set the parameter correctly, which leads to excessive tool load in the process of actual machining. In order to make more reasonable control of the machining load and tool-path, an engagement angle modeling method for multiple-circle continuous machining is presented. The distribution mode of multiple circles, dynamic changing process of engagement angle, extreme and average value of engagement angle are carefully considered. Based on the engagement angle model, numerous application techniques for mould pocket machining are presented, involving the calculation of the milling force in multiple-circle continuous machining, and rough and finish machining path planning and load control for the material accumulating region inside the pocket, and other aspects. Simulation and actual machining experiments show that the engagement angle modeling method for multiple-circle continuous machining is correct and reliable, and the related numerous application techniques for pocket machining are feasible and effective. The proposed research contributes to the analysis and control tool load effectively and tool-path planning reasonably for the material accumulating region inside the mould pocket. 相似文献
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Geometry of chip formation in circular end milling 总被引:1,自引:0,他引:1
Avisekh Banerjee Hsi-Yung Feng Evgueni V. Bordatchev 《The International Journal of Advanced Manufacturing Technology》2012,59(1-4):21-35
Machining along continuous circular tool-path trajectories avoids tool stoppage and even feed rate variation. This helps particularly in high-speed milling by reducing the effect of the machine tool mechanical structure and cutting process dynamics. With the increase in popularity of this machining concept, the need for detailed study of a valid chip formation in circular end milling is becoming necessary for accurate kinematic and dynamic modeling of the cutting process. In this paper, chip formation during circular end milling is studied with a major focus on feed per tooth and undeformed chip thickness along with their analytical derivations and numerical solutions. At first, the difference in the feed per tooth formulation for end milling along linear and circular tool-path trajectories is presented. In the next step, valid formulation of the undeformed chip thickness in circular end milling is derived by considering an epitrochoidal tooth trajectory with a wide range of the tool-path radius. The complex transcendental equations encountered in the derivation are dealt with, by a case-based approach to obtain closed-form analytical solutions. The analytical solutions of undeformed chip thickness are validated with results of numerical simulations of tool and tooth trajectories for circular end milling and also compared to the linear end milling. The close resemblance between analytical and numerical calculations of the undeformed chip thickness in circular end milling suggests validity of the proposed analytical formulations. As a case study, the cutting forces in circular end milling are calculated based on the derived chip thickness formulations and an existing mechanistic model. The calculation results reiterate the need of taking into account adjusted feed per tooth and valid chip thickness formulations in circular end milling, especially for small tool-path radii, for more realistic process modeling. 相似文献
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Generating tool-path with smooth posture change for five-axis sculptured surface machining based on cutter’s accessibility map 总被引:4,自引:4,他引:0
L. L. Li Y. F. Zhang H. Y. Li L. Geng 《The International Journal of Advanced Manufacturing Technology》2011,53(5-8):699-709
In five-axis high speed milling, one of the key requirements to ensure the quality of the machined surface is that the tool-path must be smooth, i.e., the cutter posture change from one cutter contact point to the next needs to be minimized. This paper presents a new method for generating five-axis tool-paths with smooth tool motion and high efficiency based on the accessibility map (A-map) of the cutter at a point on the part surface. The cutter’s A-map at a point refers to its posture range in terms of the two rotational angles, within which the cutter does not have any interference with the part and the surrounding objects. By using the A-map at a point, the posture change rates along the possible cutting directions (called the smoothness map or S-map) at the point are estimated. Based on the A-maps and S-maps of all the sampled points of the part surface, the initial tool-path with the smoothest posture change is generated first. Subsequently, the adjacent tool-paths are generated one at a time by considering both path smoothness and machining efficiency. Compared with traditional tool-path generation methods, e.g., iso-planar, the proposed method can generate tool-paths with smaller posture change rate and yet shorter overall path length. The developed techniques can be used to automate five-axis tool-path generation, in particular for high speed machining (finish cut). 相似文献
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Dr R. M. Boogert H. J. J. Kals F. J. A. M. van Houten 《The International Journal of Advanced Manufacturing Technology》1996,11(3):186-197
This paper reports on the development of a module to calculate automatically tool paths and cutting conditions for metal cutting operations. Process planning must select correct cutting conditions to minimise disturbances on the shop floor owing to tooling problems. Tool path and cutting condition algorithms to generate reliable NC programs have been designed. The algorithms have been implemented in the framework of a generative computer-aided process planning system, called PART. Geometrical requirements to avoid chipping of cutting teeth are considered in tool-path calculation. The cutting conditions are calculated using metal cutting process models. A method has been developed to calculate cutting forces for milling operations based on experimental data of cutting forces in turning. In the process models, various constraints of the machine tool, cutting tool, and the workpiece are considered. 相似文献
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