Machining Allowance Optimal Distribution of Thin-Walled Structure Based on Deformation Control

2017 ◽  
Vol 868 ◽  
pp. 158-165 ◽  
Author(s):  
Yu Zhi Chen ◽  
Wei Fang Chen ◽  
Rui Jun Liang ◽  
Ting Feng

Multilayer cutting is widely used in finish machining process of thin-walled parts to improve the machining precision. The paper presents a cutting allowance optimization method using genetic algorithm to improve the machining quality and efficiency of thin-walled parts in the field of aerospace. Considering the coupling relationship of the deformation between the layers in layered milling, the parameterized finite element model of thin-walled parts in side milling process is established. The best relationship between the workpiece stiffness and the cutting force is determined though iterative calculations, and the deformation caused by the cutting force can be minimized. The results show that the optimized distribution of the depth of finishing cutting was better than the experience. The method proposed in this paper can reduce the deformation of the workpiece during the machining process, and thus improve the machining accuracy.

2016 ◽  
Vol 836-837 ◽  
pp. 147-154 ◽  
Author(s):  
Xu Ding ◽  
Ting Ting Chen ◽  
Yin Fei Yang ◽  
Liang Li

The titanium alloy thin-walled structure has been widely used in aircraft construction as one of the main load-bearing components. However, it is difficult to ensure the machining accuracy because of the machining difficulties of materials and structures. This paper takes titanium alloy (Ti6Al4V) thin-walled web as the research object and analyzes the factors of milling deformation. Based on the analysis, the milling process of the titanium alloy thin-walled structure is optimized, including the decrease of cutting force and the increase of processing system rigidity. Furthermore, a reasonable milling scheme is put forward.


2010 ◽  
Vol 426-427 ◽  
pp. 284-288
Author(s):  
Dong Lu ◽  
Guo Hua Qin ◽  
Yi Ming Rong ◽  
C.M. Peng

This document Cutting stress coupled with clamping stress and initial stress affects the workpiece deformation. To analyze the workpiece deformation the initial stress model is developed. The finite element model of milling process is established and the milling force and milling heat is predicted. The multi-stress coupled model is developed and the workpiece deformation during machining process and deformation after fixtures released are predicted. This study is helpful to predict and control the deformation for thin-walled workpiece.


2011 ◽  
Vol 223 ◽  
pp. 671-678 ◽  
Author(s):  
Ming Luo ◽  
Ding Hua Zhang ◽  
Bao Hai Wu ◽  
Ming Tang

In aerospace industry, thin-walled workpieces are widely used in order to reduce the weight and to fulfill the high demands of their later applications. These workpieces are usually highly sophisticated and difficult to machine according to their geometry and material choice. In this paper, influence of material removal within the thin-walled workpiece machining operation on the dynamic properties of the workpiece and the machining process system is discussed. Aiming at learning about dynamic properties evolution during the machining operation, different milling processes of thin-walled plate are studied. Numerical simulation methods are employed in the study to investigate the dynamic properties evolution and machining stability with the material removal process in the milling process of thin-walled workpiece. The investigation results are expected to be used for designing optimized material removal sequence, which will guarantee highly material removal rate as well as highly machining accuracy of thin-walled workpiece.


2010 ◽  
Vol 29-32 ◽  
pp. 1074-1078 ◽  
Author(s):  
Zi Yang Cao ◽  
Hua Li

Miniaturized components are increasingly in demand for various industries. Micro milling operations can fabricate miniaturized components with high relative accuracy. In micro milling process, the analysis of cutting force plays an important role in characterizing the machining process, as the tool wear and surface texture depending on the cutting force. In this paper, the orthogonal experiments under slot-milling and side-milling with typical micro three dimensional parts are done by the developed three-axis micro milling machine tool, and the micro milling force is measured and analyzed. In order to improve the processing efficiency and processing accuracy of micro milling process, the impact law of the spindle speed, axial cutting depth, feed per tooth and other parameters on cutting force is deeply studied, and the machining parameters is also optimized.


Author(s):  
Ebrahim Hosseini ◽  
Shafiqur Rehman ◽  
Ashkan Alimoradi

Turn-milling is a hybrid machining process which used benefits of interrupted cutting for proceeding of round bars. However, number of controllable parameters in the hybrid process is numerous that makes optimizing the process complicated. In the present study, an optimization work has been proposed to investigate the trade-off between production rate and cutting force in roughing regime as well surface roughness and tensile residual stress in finishing regime. Number of 43 experiments based on response surface methodology was designed and carried out to gather required data for development of quadratic empirical models. Then, the adequacy and importance of process factors were analyzed using analysis of variances. Finally, desirability function was used to optimize the process in rough and finish machining regimes. The obtained results showed that selection of eccentricity and cutter speed at their maximum working range can effectively enhance the quality characteristics in both the roughing and finishing regimes.


2011 ◽  
Vol 189-193 ◽  
pp. 2116-2120
Author(s):  
Shi Min Geng ◽  
Jun Wang

The thin-walled cavity workpiece with insufficient rigid property is liable to deform during the machining process and the request of accuracy is very strict. The paper takes typical aeronautic aluminum-alloy for example, fixture is an important consideration in the operation. To reveal the influences of locating points, clamping sequence and loading ways on the distortion of thin-walled cavity part, finite element models were established to simulate the clamping operation. The result shows the preferable scheme is that the distance of the clamping locations are far each other, clamping forces are firstly applied on the surface with high rigid and all clamping forces are applied in many steps. The scheme can effectively control the deformation of clamp ,and furthermore improve the machining accuracy.


Author(s):  
Gongyu Liu ◽  
Jiaqiang Dang ◽  
Weiwei Ming ◽  
Qinglong An ◽  
Ming Chen ◽  
...  

The milling of thin-walled workpieces is a common process in many industries. However, the machining defects are easy to occur due to the vibration and/or deformation induced by the poor stiffness of the thin structures, particularly when side milling the edges of plates. To this problem, an attempt by inclining the tool to a proper tilt angle in milling the edges of plates was proposed in this paper, in order to decrease the cutting force component along the direction of the lowest stiffness of the plates, and therefore to mitigate the machining vibration and improve the machined surface quality effectively. First, the milling force model in consideration of the undeformed chip thickness and the tool-workpiece engagement (TWE) was introduced in detail. Then, a new analytical assessment model based on the precisely established cutting force model was developed so as to obtain the optimum tool tilt angle for the minimum force-induced defects after the operation. Finally, the reliability and correctness of the theoretical force model and the proposed assessment model were validated by experiments. The methodology in this paper could provide practical guidance for achieving high-quality machined surface in the milling operation of thin-walled workpieces.


2020 ◽  
Vol 29 ◽  
pp. 2633366X2094252
Author(s):  
Yunan Liu ◽  
Shutao Huang ◽  
Keru Jiao ◽  
Lifu Xu

Thin-walled workpieces of silicon carbide particle-reinforced aluminum matrix (SiCp/Al) composites with outstanding properties have been widely applied in many fields, such as automobile, weapons, and aerospace. However, the thin-walled workpieces exhibit poor rigidity, large yield ratio, and easily deform under the cutting force and cutting heat during the machining process. Herein, in order to improve the processing efficiency and precision of higher volume fraction SiCp/Al composite thin-walled workpieces, the influence of different high-speed milling parameters and machining paths on the edge defects is analyzed. The results reveal that the cutting force initially increased and then decreased with the cutting speed. Besides, the cutting force steadily increased with radial cutting depth and feed per tooth, but the influence of feed per tooth is less than radial cutting depth. After up-milling cut-in and cut-out processing and down-milling cut-out processing, the cut-in end of the workpiece exhibited higher breakage and obvious edge defects. However, the workpiece edges remained intact after down-milling cut-in processing. In conclusion, a higher cutting speed, a smaller radial cutting depth, and moderate feed per tooth are required to decrease the cutting force during the milling of SiCp/Al composite thin-walled workpiece. Furthermore, down-milling cut-in processing mode can reduce the edge defects and improve the processing efficiency and precision of the workpiece.


2016 ◽  
Vol 693 ◽  
pp. 843-849
Author(s):  
An Hai Li ◽  
Jun Zhao ◽  
He Lin Pan ◽  
Zhao Chao Gong

In order to acquire high machining quality and minimum machining time, cutting forces are usually modeled to understand the milling process, simulate or predict cutting forces, and optimize the machining parameters. In this paper, side milling tests were conducted on superalloy Inconel 718 with a solid carbide end mill, and the cutting forces vs. cutting time were measured. The average cutting forces were extracted from the measured instantaneous cutting forces under different feed rates of experiments, and the components of the shear forces and edge forces were determined by using the linear regression of the experimental data. The cutting force coefficients, including shear force coefficients and edge force coefficients, were identified. In addition, the algorithms of the mathematical model were implemented in Matlab. The predicted cutting forces were in good agreement with the experimentally measured forces, and the validation of the cutting force model was demonstrated.


2009 ◽  
Vol 69-70 ◽  
pp. 428-432 ◽  
Author(s):  
Qing Hua Song ◽  
Yi Wan ◽  
Shui Qing Yu ◽  
Xing Ai ◽  
J.Y. Pang

A method for predicting the stability of thin-walled workpiece milling process is described. The proposed approach takes into account the dynamic characteristics of workpiece changing with tool positions. A dedicated thin-walled workpiece representative of a typical industrial application is designed and modeled by finite element method (FEM). The workpiece frequency response function (FRF) depending on tool positions is obtained. A specific 3D stability chart (SC) for different spindle speeds and different tool positions is then elaborated by scanning the dynamic properties of workpiece along the machined direction throughout the machining process. The dynamic optimization of cutting parameters for increasing the chatter free material removal rate and surface finish is presented through considering the chatter vibration and forced vibration. The investigations are compared and verified by high speed milling experiments with flexible workpiece.


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