共查询到20条相似文献,搜索用时 984 毫秒
1.
J. J. Junz Wang H. C. Chang 《The International Journal of Advanced Manufacturing Technology》2004,24(5-6):415-424
Mechanistic cutting constants serve well in predicting milling forces, monitoring the milling process as well as in helping to understand the mechanistic phenomena of a machining process for a unique pair of workpiece and cutter materials under various types of cutting edge geometry. This paper presents a unified approach in identifying the six shearing and ploughing cutting constants for a general helical end mill from the dynamic components of the measured milling forces in a single cutting test. The identification model is first presented assuming the milling force is measured with a known phase angle of the cutter spindle. When the phase angle of the cutter rotation is not available, as is the case for most milling machines, it is shown that the true phase angle can be identified through the theoretical phase relationship between the different harmonic components of the milling forces measured with an arbitrary phase angle. The numerical simulation and the experimental results for ball and cylindrical end mills are presented to demonstrate and validate the identification methods. 相似文献
2.
Wen-Hou Chu Pi-Cheng Tung 《The International Journal of Advanced Manufacturing Technology》2005,25(3-4):281-287
In end milling of pockets, variable radial depth of cut is generally encountered as the end mill enters and exits the corner, which has a significant influence on the cutting forces and further affects the contour accuracy of the milled pockets. This paper proposes an approach for predicting the cutting forces in end milling of pockets. A mathematical model is presented to describe the geometric relationship between an end mill and the corner profile. The milling process of corners is discretized into a series of steady-state cutting processes, each with different radial depth of cut determined by the instantaneous position of the end mill relative to the workpiece. For the cutting force prediction, an analytical model of cutting forces for the steady-state machining conditions is introduced for each segmented process with given radial depth of cut. The predicted cutting forces can be calculated in terms of tool/workpiece geometry, cutting parameters and workpiece material properties, as well as the relative position of the tool to workpiece. Experiments of pocket milling are conducted for the verification of the proposed method. 相似文献
3.
Process modeling and toolpath optimization for five-axis ball-end milling based on tool motion analysis 总被引:2,自引:2,他引:0
Liqiang Zhang 《The International Journal of Advanced Manufacturing Technology》2011,57(9-12):905-916
In free-form surface machining, the prediction of five-axis ball-end milling forces is quite a challenge due to difficulties of determining the underformed chip thickness and engaged cutting edge. Part and tool deflections under high cutting forces may result in poor part quality. To solve these concerns, this paper presents process modeling and optimization method for five-axis milling based on tool motion analysis. The method selected for geometric stock modeling is the dexel approach, and the extracted cutter workpiece engagements are used as input to a force prediction. The cutter entry?Cexit angles and depth of cuts are found and used to calculate the instantaneous cutting forces. The process is optimized by varying the feed as the tool?Cworkpiece engagements vary along the toolpath, and the unified model provides a powerful tool for analyzing five-axis milling. The new feedrate profiles are shown to considerably reduce the machining time while avoiding process faults. 相似文献
4.
Klaus Schützer Luciana Wasnievski da Silva de Luca Ramos Jan Mewis Marcelo Octavio Tamborlin Crhistian Raffaelo Baldo 《The International Journal of Advanced Manufacturing Technology》2018,99(1-4):225-232
The improvement of micro-milling processes implies the application of advanced analysis and modeling techniques to derive a deeper process understanding. Because of micro-scale effects, monitoring, and measurement systems applied in conventional milling are in most cases not suitable for identifying optimal cutting conditions. Therefore, analytical and mechanical models have been developed in recent years to account for impact factors dominating the micro-milling errors. Within the research presented in this publication, geometric, kinematic, and dynamic models have been adjusted and dimensioned according to the dominating impact factors in micro-milling and have been consolidated to enable for a time-domain simulation. The effect of element size of discretized workpiece and tool as well as the time step size on cutting forces has been evaluated. The accuracy of predicting cutting forces has been investigated and a good agreement of measured and simulated cutting forces has been found. Finally, a mold for a micro-fluidic device has been machined virtually and experimentally to evaluate the accuracy of the integrated models in predicting the final quality of a micro-milled part in terms of surface quality parameters. 相似文献
5.
Force prediction and stability analysis of plunge milling of systems with rigid and flexible workpiece 总被引:1,自引:1,他引:0
Ahmed Damir Eu-Gene Ng Mohamed Elbestawi 《The International Journal of Advanced Manufacturing Technology》2011,54(9-12):853-877
Time domain simulation model is developed to study the dynamics of plunge milling process for system with rigid and flexible workpiece. The model predicts the cutting forces, system vibration as a function of workpiece and tool dynamics, tool setting errors, and tool kinematics and geometry. A horizontal approach is used to compute the chip area to consider the contribution of the main and side edge in the cutting zone and to deal with any geometric shape of the insert. The dynamic chip area is evaluated based on the interaction of the insert main and side cutting edges with the workpiece geometry determined by the pilot hole and surface left by the previous insert. For the case of system with a flexible workpiece, the workpiece dynamics, as well as its variation in the axial direction with respect to hole location, is considered in the simulation. Cutting tests with single and double inserts were carried out to validate the simulation model and predicted stability lobe for both systems with rigid and flexible workpiece and to check the correctness of the cutting coefficient model. Good agreement was found between the measured and the predicted cutting forces and vibration signals and power spectra. This indicates the ability of the model to accurately predict cutting forces, system vibration, and process stability for process planning prior to machining. The results show dominance of workpiece dynamics in the axial direction for systems with flexible workpiece due to its flexibility as compared to the tool axial rigidity. On the other hand, chatter behavior was found to occur due to tool lateral modes for case of rigid workpiece. 相似文献
6.
7.
Dynamic Force Modelling for a Ball-End Milling Cutter Based on the Merchant Oblique Cutting Theory 总被引:1,自引:0,他引:1
Shui-Jin Li Yun-Fei Zhou Ren-Cheng Jin Zhou Ji 《The International Journal of Advanced Manufacturing Technology》2001,17(7):477-483
A new dynamic force model for a ball-end milling cutter is presented in this paper. Based on the principle of the power remaining
constant in cuts, the Merchant oblique cutting theory has been successfully used for the differential cutting edge segment
of a ball-end milling cutter. A concise method for characterising the relationship of the complex geometry of a ball-end milling
cutter and the milling process variables is determined, so that the force coefficients can be decomposed. The geometric property
of a ball-end milling cutter and the dynamics of the milling process are integrated into the general model to eliminate the
need for the experimental calibration of each cutter geometry and milling process variable. The milling experiments prove
that this model can predict accurately the cutting forces in three Cartesian directions. 相似文献
8.
Cutting forces prediction in generalized pocket machining 总被引:1,自引:1,他引:0
Zhao-cheng Wei Min-jie Wang Xian-guo Han 《The International Journal of Advanced Manufacturing Technology》2010,50(5-8):449-458
Cutting force prediction is important for the planning and optimization of machining process. This paper presents an approach to predict the cutting forces for the whole finishing process of generalized pocket machining. The equivalent feedrate is introduced to quantify the actual speed of cutting cross-section in prediction of cutting force for curved surface milling. For convenience, to analyze the process with varying feed direction and cutter engagement, the milling process for generalized pocket is discretized into a series of small processes. Each of the small processes is transformed into a steady-state machining, using a new approximation method. The cutting geometries of each discrete process, i.e., feed direction, equivalent feedrate per tooth, entry angle, and exit angle are calculated based on the information refined from NC code. An improved cutting force model which involves the effect of feed direction on cutting forces prediction is also presented. A machining example of a freeform pocket is performed, and the measured cutting forces are compared with the predictions. The results show that the proposed approach can effectively predict the variation of cutting forces in generalized pocket machining. 相似文献
9.
Gaetano Massimo Pittalà Michele Monno 《The International Journal of Advanced Manufacturing Technology》2010,47(5-8):543-555
Milling operations are very common in manufacturing. Often it represents the last operation, determining the final product quality. Then an accurate mathematical model is important in order to design the cutting process, in terms of cutting process, and the geometry of the insert, for tool manufacturers. The finite element modeling (FEM) simulation permits the prediction of the cutting forces, stresses, and temperatures of the cutting process. The 2D FEM can be a reasonable approximation, where the deformation can be considered plain. For the milling operations, this assumption can be suitable if the depth of cut is much bigger than nose radius. But in the normal situation the insert has a complex geometry and the bidimensional model of the milling operation is not appropriate. The 3D FEM involves different element formulations, different remeshing algorithm, and different boundary conditions, so an independent approach is necessary. The approach followed in this paper is to model three-dimensionally the milling operation, considering the real geometry of the insert. The FEM simulation is carried out with a commercial code (3D DEFORM?). First the rheological model has been calibrated using OXCUT software, developed at the ERC/NSM, and a sensitivity analysis about friction model has been performed. Milling tests are conducted and the measured cutting forces are compared to finite element modeling results. The results show an acceptable agreement with experimental results in the range of cutting speed and feed rate considered. 相似文献
10.
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
11.
12.
E. Ozturk 《Machining Science and Technology》2013,17(3):287-311
5-axis milling operations are common in several industries such as aerospace, automotive and die/mold for machining of sculptured surfaces. In these operations, productivity, dimensional tolerance integrity and surface quality are of utmost importance. Part and tool deflections under high cutting forces may result in unacceptable part quality whereas using conservative cutting parameters results in decreased material removal rate. Process models can be used to determine the proper or optimal milling parameters for required quality with higher productivity. The majority of the existing milling models are for 3-axis operations, even the ones for ball-end mills. In this article, a complete geometry and force model are presented for 5-axis milling operations using ball-end mills. The effect of lead and tilt angles on the process geometry, cutter and workpiece engagement limits, scallop height, and milling forces are analyzed in detail. In addition, tool deflections and form errors are also formulated for 5-axis ball-end milling. The use of the model for selection of the process parameters such as lead and tilt angles that result in minimum cutting forces are also demonstrated. The model predictions for cutting forces and tool deflections are compared and verified by experimental results. 相似文献
13.
MODELING OF 5-AXIS MILLING PROCESSES 总被引:2,自引:0,他引:2
5-axis milling operations are common in several industries such as aerospace, automotive and die/mold for machining of sculptured surfaces. In these operations, productivity, dimensional tolerance integrity and surface quality are of utmost importance. Part and tool deflections under high cutting forces may result in unacceptable part quality whereas using conservative cutting parameters results in decreased material removal rate. Process models can be used to determine the proper or optimal milling parameters for required quality with higher productivity. The majority of the existing milling models are for 3-axis operations, even the ones for ball-end mills. In this article, a complete geometry and force model are presented for 5-axis milling operations using ball-end mills. The effect of lead and tilt angles on the process geometry, cutter and workpiece engagement limits, scallop height, and milling forces are analyzed in detail. In addition, tool deflections and form errors are also formulated for 5-axis ball-end milling. The use of the model for selection of the process parameters such as lead and tilt angles that result in minimum cutting forces are also demonstrated. The model predictions for cutting forces and tool deflections are compared and verified by experimental results. 相似文献
14.
The cutting tool wear degrades the quality of the product in the manufacturing process, for this reason an on-line monitoring of the cutting tool wear level is very necessary to prevent any deterioration. Unfortunately there is no direct manner to measure the cutting tool wear on-line. Consequently we must adopt an indirect method where wear will be estimated from the measurement of one or more physical parameters appearing during the machining process such as the cutting force, the vibrations, or the acoustic emission, etc. The main objective of this work is to establish a relationship between the acquired signals variation and the tool wear in high speed milling process; so an experimental setup was carried out using a horizontal high speed milling machine. Thus, the cutting forces were measured by means of a dynamometer whereas; the tool wear was measured in an off-line manner using a binocular microscope. Furthermore, we analysed cutting force signatures during milling operation throughout the tool life. This analysis was based on both temporal and frequential signal processing techniques in order to extract the relevant indicators of cutting tool state. Our results have shown that the variation of the variance and the first harmonic amplitudes were linked to the flank wear evolution. These parameters show the best behavior of the tool wear state while providing relevant information of this later. 相似文献
15.
Zhang Xuewei Yu Tianbiao Wang Wanshan 《The International Journal of Advanced Manufacturing Technology》2016,87(9-12):2785-2796
The micro end milling uses the miniature tools to fabricate complexity microstructures at high rotational speeds. The regenerative chatter, which causes tool wear and poor machining quality, is one of the challenges needed to be solved in the micro end milling process. In order to predict the chatter stability of micro end milling, this paper proposes a cutting forces model taking into account the process nonlinearities caused by tool run-out, trajectory of tool tip and intermittency of chip formation, and the process damping effect in the ploughing-dominant and shearing-dominant regimes. Since the elasto-plastic deformation of micro end milling leads to large process damping which will affect the process stability, the process damping is also included in the cutting forces model. The micro end milling process is modeled as a two degrees of freedom system with the dynamic parameters of tool-machine system obtained by the receptance coupling method. According to the calculated cutting forces, the time-domain simulation method is extended to predict the chatter stability lobes diagrams. Finally, the micro end milling experiments of cutting forces and machined surface quality have been investigated to validate the accuracy of the proposed model. 相似文献
16.
T-slot milling is one of the most common milling processes in industry. Despite recent advances in machining technology, productivity of T-slot milling is usually limited due to the process limitations such as high cutting forces and stability. If cutting conditions are not selected properly the process may result in the poor surface finish of the workpiece and the potential damage to the machine tool. Currently, the predication of chatter stability and determination of optimal cutting conditions based on the modeling of T-slot milling process is an effective way to improve the material removal rate(MRR) of a T-slot milling operation. Based on the geometrical model of the T-slot cutter, the dynamic cutting force model was presented in which the average directional cutting force coefficients were obtained by means of numerical approach, and leads to an analytical determination of stability lobes diagram(SLD) on the axial depth of cut. A new kind of SLD on the radial depth of cut was also created to satisfy the special requirement of T-slot milling. Thereafter, a dynamic simulation model of T-slot milling was implemented using Matlab software. In order to verify the effectiveness of the approach, the transfer functions of a typical cutting system in a vertical CNC machining center were measured in both feed and normal directions by an instrumented hammer and accelerators. Dynamic simulations were conducted to obtain the predicated SLD under specified cutting conditions with both the proposed model and CutPro?. Meanwhile, a set of cutting trials were conducted to reveal whether the cutting process under specified cutting conditions is stable or not. Both the simulation comparison and experimental verification demonstrated that the satisfactory coincidence between the simulated, the predicted and the experimental results. The chatter-free T-slot milling with higher MRR can be achieved under the cutting conditions determined according to the SLD simulation. 相似文献
17.
M. Krüger B. Denkena 《The International Journal of Advanced Manufacturing Technology》2013,65(5-8):1067-1080
This paper presents a model-based approach for the identification of tool runout and the estimation of surface roughness from measured cutting forces. In the first part of the paper, the effect of tool runout on variations in the cutting forces and the effect on surface roughness generation are studied. Thereby, several influencing parameters are identified and examined systematically. Based on theoretical considerations, systematic relationships between tool runout, resultant process force variations, and surface roughness characteristics are deduced. The sensitivity of process force variation is investigated for varying runout parameters by experimental tests. In the next part, the model-based runout identification method is developed, which identifies runout parameters accurately from the measured process forces. The approach has been tested extensively and was verified by measured runout parameters and the correlation of surface roughness characteristics of the machined workpiece. The performance of the developed approach is demonstrated in the final part by comparing the result of the model-based surface reconstruction with the measured surface topography. 相似文献
18.
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
19.