共查询到20条相似文献,搜索用时 46 毫秒
1.
Jeong Hoon Ko Kah Chuan Shaw 《International Journal of Precision Engineering and Manufacturing》2009,10(4):19-25
Chatter has been a problem in CNC machining process especially during pocket milling process using an end mill with low stiffness.
Since an iterative time-domain chatter solution consumes a computing time along tool paths, a fast chatter prediction algorithm
for pocket milling process is required by machine shop-floor for detecting chatter prior to real machining process. This paper
proposes the systematic solution based on integration of a stability law in frequency domain with geometric information of
material removal for a given set of tool paths. The change of immersion angle and spindle speed determines the variation of
the stable cutting depth along cornering cut path. This proposed solution transforms the milling stability theory toward the
practical methodology for the stability prediction over the NC pocket milling. 相似文献
2.
HSM-ADAPTED TOOL PATH CALCULATION FOR POCKETING 总被引:1,自引:0,他引:1
Vincent Pateloup H l ne Chanal Emmanuel Duc Pascal Ray 《Machining Science and Technology》2006,10(2):181-196
High-speed milling imposes a precise choice of cutting conditions, because the feed rate and the radial depth of cut influence the maximum forces on cutting edges. But the control of these cutting conditions for pocket machining is very difficult due to the complex tool path shape. Our work is focused on the improvement of the geometrical definition of the tool path, in order to ensure a better respect of the cutting conditions required for HSM. Initially, we study variations in the radial depth of cut and the real feed rate, when the tool follows usual tool paths for pocketing. Numerical simulations and experimental measurements are used. Next, a new tool path computation method that increases the real feed rate and respects radial depth of cut requirements is proposed. The computation takes into account both the geometrical requirements and the HSM dynamic requirements. Such tool paths reduce machining time and respect initial cutting parameters which are favorable for process reliability and tool life. 相似文献
3.
Vincent Pateloup Hélène Chanal Emmanuel Duc Pascal Ray 《Machining Science and Technology》2013,17(2):181-196
High-speed milling imposes a precise choice of cutting conditions, because the feed rate and the radial depth of cut influence the maximum forces on cutting edges. But the control of these cutting conditions for pocket machining is very difficult due to the complex tool path shape. Our work is focused on the improvement of the geometrical definition of the tool path, in order to ensure a better respect of the cutting conditions required for HSM. Initially, we study variations in the radial depth of cut and the real feed rate, when the tool follows usual tool paths for pocketing. Numerical simulations and experimental measurements are used. Next, a new tool path computation method that increases the real feed rate and respects radial depth of cut requirements is proposed. The computation takes into account both the geometrical requirements and the HSM dynamic requirements. Such tool paths reduce machining time and respect initial cutting parameters which are favorable for process reliability and tool life. 相似文献
4.
Hyun-Chul Kim 《Journal of Mechanical Science and Technology》2010,24(5):1019-1027
Many mechanical parts are manufactured by milling machines. Hence, geometrically efficient algorithms for tool path generation,
along with physical considerations for better machining productivity with guaranteed machining safety, are the most important
issues in milling. In this paper, an optimized path generation algorithm for direction-parallel milling, a process commonly
used in the roughing stage as well as the finishing stage and based on an incomplete 2-manifold mesh model, namely, an inexact
polyhedron widely used in recent commercialized CAM software systems, is presented. First of all, a geometrically efficient
tool path generation algorithm using an intersection points-graph is introduced. Although the tool paths obtained from geometric
information have been successful in forming desired shapes, physical process concerns such as cutting forces and chatters
have seldom been considered. In order to cope with these problems, an optimized tool path that maintains a constant MRR for
constant cutting forces and avoidance of chatter vibrations, is introduced, and verified experimental results are presented.
Additional tool path segments are appended to the basic tool path by means of a pixel-based simulation technique. The algorithm
was implemented for two-dimensional contiguous end milling operations with flat end mills, and cutting tests measured the
spindle current, which reflects machining characteristics, to verify the proposed method. 相似文献
5.
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
6.
7.
8.
Combined reparameterization-based spiral toolpath generation for five-axis sculptured surface machining 总被引:1,自引:0,他引:1
Fei Ren Yuwen Sun Dongming Guo 《The International Journal of Advanced Manufacturing Technology》2009,40(7-8):760-768
Reparameterization-based toolpath generation methods are usually adopted for machining triangular meshes, trimmed surfaces and compound surfaces. The quality of the reparameterization has an important effect on that of the surface. In this paper, a combined reparameterization procedure is introduced to generate an optimal mapping between the designed surface and a specified planar circular region with relatively less distortion both in length and in angle. Then, for five-axis sculptured surface machining the mathematical model of spiral guide path with maximum path interval is constructed in the circular region. Cutter contact paths are obtained by inversely mapping the guide path onto the designed surface. Under constraints of gouging and collision, continuous and optimal cutter orientations are subsequently calculated. Finally, the results of simulation and experiment of the machining process are given to illustrate the feasibility and applicability of the proposed method. 相似文献
9.
为解决运用Master CAM软件的外形铣削刀具路径对偏心工件加工时,存在浪费刀具路径的现象,需要作做辅助线纠正的问题,尝试不作辅助线,使用Master CAM挖槽刀具路径对偏心工件加工;通过对挖槽各种类型的刀具路径及外形铣削刀具路径,对偏心工件的加工效果进行比较,得出了边界再加工挖槽刀具路径适合对偏心工件加工的结论。 相似文献
10.
Chen Zhang Xihui Liu Jiwen Fang Laishui Zhou 《The International Journal of Advanced Manufacturing Technology》2011,53(1-4):121-130
In the milling process, tool wear has a great influence on product machining quality, especially for a difficult-to-cut material. In this paper, a new approach based on shape mapping is proposed to acquire tool wear in order to establish an off-line tool wear predicting model for assessing the degree of wear and remaining useful life. The new approach maps tool wear shape into a metal material by milling holes mode after finishing each of the machining experiments. The metal material has low influence on tool wear compared to the experimental material. Thus, a series of mapped holes, which can represent the worn tool information, are formed on the metal material when finishing all milling experiments. These mapped holes on the metal material are analyzed according to all types of milling cutters in order to establish the relationship between the characteristic parameters of these mapped holes and tool wear. According to the established relationship, the characteristic parameters of these mapped holes are measured on the coordinate measure machine. The tool wear of each machining experiment can be obtained from the measured characteristic parameters of these mapped holes. The new tool wear estimation method does not require the stoppage of the machine tool and the removal of the cutter to measure tool wear in the process of conducting tool wear experiments. The new method can increase the machine tool efficiency of tool wear machining experiments and provide an efficient way to acquire tool wear in the process of establishing an off-line tool wear predicting model. In order to verify the new tool wear estimation method, a series of machining experiments were conducted on the five-axis machining center for cemented carbide cutting tool milling stainless steel. Experiments show that the shape mapping strategy of tool wear can allow for an effective assessment of tool wear and indicate good correlation with the expected wear characteristics and easily conduct tool wear experiments. 相似文献
11.
用球头铣刀高速铣削斜面是在三轴加工中心上加工模具时的一种走刀方式。根据球头铣刀高速铣削斜面的特点,建立了在垂直向上和向下、水平向上和向下四种走刀方式下高速铣削45°斜面,以及在垂直向下走刀方式下高速铣削30°、60°、75°斜面的三维有限元模型,以分析不同走刀方式下铣削斜面以及铣削不同角度斜面时切削力和切削温度的变化规律。模拟结果表明,在铣削45°斜面时,采用向上走刀方式较向下走刀方式的切削力幅值小、波动大,且切削温度高;采用垂直向下走刀方式铣削大角度斜面时也出现类似情况。对切削力的实测结果验证了该模型的可靠性。 相似文献
12.
Hyun-Chul Kim Min-Yang Yang 《The International Journal of Advanced Manufacturing Technology》2008,35(7-8):803-813
The majority of mechanical parts are manufactured by milling machines. Hence, geometrically efficient algorithms for tool
path generation and physical considerations for better machining productivity with guarantee of machining safety are the most
important issues in milling tasks. In this paper, we present an optimized path-generation algorithm for zigzag milling, which
is commonly used in the roughing stage as well as in the finishing stage, based on an incomplete two-manifold mesh model,
namely, an inexact polyhedron that is widely used in recent commercialized CAM software systems. First of all, a geometrically
efficient tool path generation algorithm using an intersection points-graph is introduced. Although the tool path obtained
from geometric information has been successful to make a desirable shape, it seldom considers physical process concerns like
cutting forces and chatter. In order to cope with these problems, an optimized tool path that maintains constant MRR in order
to achieve constant cutting forces and to avoid chatter vibrations at all times is introduced and the result is verified.
Additional tool path segments are appended to the basic tool path by using a pixel-based simulation technique. The algorithm
was implemented for two-dimensional contiguous end-milling operations with flat end mills and cutting tests were conducted
by measuring the spindle current, (which reflect machining situations) to verify the significance of the proposed method. 相似文献
13.
Hemant Ramaswami Raj Shankar Shaw Sam Anand 《The International Journal of Advanced Manufacturing Technology》2011,53(9-12):963-977
Selection of the optimal set of cutting tools is one of the most important steps in process planning for 2.5-D pocket machining. Conventional CAM software requires considerable input from the user in terms of selection of tool sizes and machining strategy. This trial-and-error procedure to determine the optimal process sequence tends to generate conservative and suboptimal results. This paper presents a methodology for optimal selection of a sequence of tools to minimize the total time required to end mill a non-convex polygonal pocket with or without islands using the staircase milling strategy. The algorithm decomposes the pocket geometry into convex regions and mills each region independently by selecting a sequence of tools based on the accessibility of various tools to the region. Strategies have been developed for machining the main pass and the subsequent leftover areas in order to obtain the final pocket geometry. Subsequently, the machining times for each decomposed area are aggregated while accounting for the need to use multiple passes, non-cutting time, and the tool change time. A dynamic programming approach is used to determine the optimal set of tools which minimizes the total processing time. The effect of varying the non-cutting speed and tool change time on the tool path length and number of tool selection is studied. 相似文献
14.
Christophe Tournier Emmanuel Duc 《The International Journal of Advanced Manufacturing Technology》2005,25(9-10):867-875
This paper presents a new method of computing constant scallop height tool paths in 5-axis milling on sculptured surfaces. Usually, iso-scallop tool path computation methods are based on approximations. The attempted scallop height is modelled in a given plane to ensure a fast computation of the tool path. We propose a different approach, based on the concept of the machining surface, which ensures a more accurate computation. The machining surface defines the tool path as a surface, which applies in 3- or 5-axis milling with the cutting tools usually used. The machining surface defines a bi-parametric modelling of the locus of a particular point of the tool, and the iso-scallop surface allows to easily find iso-scallop tool centre locations. An implementation of the algorithms is done on a free-form surface with a filleted end mill in 5-axis milling. 相似文献
15.
Tool path generation and modification for constant cutting forces in direction parallel milling 总被引:1,自引:0,他引:1
Hyun-Chul Kim 《The International Journal of Advanced Manufacturing Technology》2011,52(9-12):937-947
This paper presents an optimized path generation algorithm for direction parallel milling, which is commonly used in the roughing and finishing stages. First, a geometrically efficient tool path generation algorithm using an intersection points graph is introduced. Second, the generated tool path is modified as an optimized tool path that maintains a constant material removal rate to achieve a constant cutting force and avoid chatter vibration, and the results are verified. Additional tool path segments are appended to the basic tool path through a pixel-based simulation technique. The algorithm is implemented for two-dimensional contiguous end milling operations with flat end mills, and cutting tests are conducted by measuring the spindle current, which reflects the changing machining situations, to verify the performance of the proposed method. 相似文献
16.
五轴加工刀具路径生成的有效加工域规划方法 总被引:3,自引:0,他引:3
为复杂曲面五轴数控加工的刀具路径优化生成问题提出一种新的有效加工域规划方法。在对工件被加工表面和刀具的几何特征进行分析的基础上,得到在加工件表面上各处的最优可加工域宽度和刀具切削方向。通过采用离散采样和插值计算生成优化的有效加工域集,得到最优化的初始刀具路径;同时建立一种迭代搜索算法,用于解决最优加工域的选择规划问题。采用此算法生成优化的后续刀具路径,使得有效加工域最终完全覆盖整个被加工表面。给出的示例显示相对于传统的五轴加工刀具路径生成算法,有效加工域规划方法可以减少刀具路径的总长度和加工时间,得到更为优化的刀具路径和更好的工件表面质量,因此有效加工域规划方法可以被用于五轴数控加工实践以降低加工成本和提高产品质量。 相似文献
17.
L. Geng Y. F. Zhang H. Y. Li 《The International Journal of Advanced Manufacturing Technology》2013,69(9-12):2481-2492
This paper presents an optimization method for planning five-axis end milling (finish cut) of sculptured surfaces with multi-cutters. Compared to single-cutter machining, the application of multi-cutters can produce much shorter cutter location (CL) paths and, hence, reduce the machining time. The work presented in this paper focuses on the selection of an optimal multi-cutter set that is utilized to finish different regions of a design surface, followed by the generation of CL paths for each region/cutter combination. The planning starts by identifying all the feasible cutters that form all the possible multi-cutter sets by evaluating their accessibility. The candidate multi-cutter sets are then extracted by maintaining every cutter's cutting region sufficiently large. Based on a proposed method for machining time estimation without generating the tool path, the optimal multi-cutter set with the best cutting efficiency is selected. The iso-planar CL paths are then generated for the cutters in the optimal set for machining their allocated surface regions. Examples are given to show the validity and robustness of the developed methods. 相似文献
18.
Contour parallel milling tool path generation for arbitrary pocket shape using a fast marching method 总被引:2,自引:2,他引:0
Sandeep Dhanik Paul Xirouchakis 《The International Journal of Advanced Manufacturing Technology》2010,50(9-12):1101-1111
Contour parallel tool paths are among the most widely used tool paths for planer milling operations. A number of exact as well as approximate methods are available for offsetting a closed boundary in order to generate a contour parallel tool path; however, the applicability of various offsetting methods is restricted because of limitations in dealing with pocket geometry with and without islands, the high computational costs, and numerical errors. Generation of cusps, segmentation of rarefied corners, and self-intersection during the offsetting operations and finding a unique offsetting solution for pocket with islands are among the associated problems in contour tool path generation. Most of methods are inherently incapable of dealing with such problems and use complex computational routines to identify and rectify these problems. Also, these rectifying techniques are heavily dependent on the type of geometry, and hence, the application of these techniques for arbitrary boundary conditions is limited and prone to errors. In this paper, a new mathematical method for generation of contour parallel tool paths is proposed which is inherently capable of dealing with the aforementioned problems. The method is based on a boundary value formulation of the offsetting problem and a fast marching method based solution for tool path generation. This method handles the topological changes during offsetting naturally and deals with the generation of discontinuities in the slopes by including an “entropy condition” in its numerical implementation. The appropriate modifications are carried out to achieve higher accuracy for milling operations. A number of examples are presented, and computational issues are discussed for tool path generation. 相似文献
19.
Kang Jia Jun Hong Lijun Fan 《The International Journal of Advanced Manufacturing Technology》2017,89(1-4):87-100
Despite helical broaching being an excellent method for internal helical ring gear manufacturing with regard to its machining efficiency and precision, the manufacture of this special helical broaching tool is a severe challenge because of its complex geometric structure like dual-spiral and step-feed pattern of cutting teeth as well as the tiny offset of its cutting edges, particularly considering the expensive tool cost and long manufacturing period. Aiming at finding an efficient and reliable machining method for this type of helical broaching tool, this paper developed a complete set of machining routes and corresponding paths to grind its cutting teeth. Through detailed investigation, the geometric structure of the helical broaching tool, the tooth index model, and two kinds of tooth coordinate calculating methods were proposed. The rough cutting section is suggested to be machined in four stages, while the length-varying reciprocating path and the single-tooth grinding path patterns are presented. Then, a special step-feed structure-driven grinding path pattern and three stages are developed to perform the manufacture of the finishing cutting section. Finally, the progressively truthful machined entities validate that the developed machining routes and three path patterns are practicable for helical broaching tool manufacturing and that they are effective in enhancing the machining efficiency and quality. In addition, the concise operations prove the friendly programmability of the grinding paths. 相似文献
20.
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