Rigidity Regulation Approach for Geometric Tolerance Optimization in End Milling of Thin-walled Components

2021 ◽  
pp. 1-34
Author(s):  
Ankit Agarwal ◽  
K A Desai
Keyword(s):  
End Milling ◽  
Traditional Approach ◽  
Force Model ◽  
Geometric Tolerances ◽  
Novel Approach ◽  
Cutting Sequences ◽  
Finish Cutting ◽  
Thin Walled ◽  
Cutting Sequence ◽  
Regulation Approach

Abstract The paper presents a novel approach to improve geometric tolerances (flatness and cylindricity) by manipulating the rigidity among finishing and roughing cutting sequences during end milling of thin-walled components. The proposed approach considers the design configuration of the thin-walled component as an input and aims to determine semi-finished geometry such that the geometric tolerances are optimized while performing finish cutting sequence. The objective is accomplished by combining Mechanistic force model, Finite Element (FE) analysis based workpiece deflection model and Particle Swarm Optimization (PSO) technique to determine optimal disposition of material along the length of component thereby regulating rigidity. The algorithm has been validated by determining rigidity regulated semi-finished geometries for thin-walled components having straight, concave and convex configurations. The outcomes of the proposed algorithm are substantiated further by conducting a set of end milling experiments for each of these cases. The results of the proposed strategy are compared with a traditional approach considering no change in the rigidity of component along length of the cut. It is demonstrated that the proposed approach can effectively optimize geometric tolerances for thin-walled components during end milling operation.

Modeling of flatness errors in end milling of thin-walled components

2020 ◽  
pp. 095440542094921
Author(s):  
Ankit Agarwal ◽  
Kaushal A Desai
Keyword(s):  
End Milling ◽  
Force Model ◽  
Related Factors ◽  
Element Analysis ◽  
Computational Tools ◽  
Geometric Dimensioning And Tolerancing ◽  
Thin Walled ◽  
The Individual ◽  
Machining Strategies ◽  
Flatness Error

Machined components deviate in size, form, and orientation in comparison to actual features realized by the designer. The deviations originate from several process-related factors and can be specified as per the Geometric Dimensioning and Tolerancing standards (ASME Y14.5-2009 or ISO 1101:2017). According to these standards, the deviation of planar or flat components is expressed in the form of flatness error. This article presents an overall framework to estimate static deflection–induced flatness errors during end milling of thin-walled planar components. The framework incorporates the Mechanistic force model, finite element analysis–based workpiece deflection model, and particle swarm optimization–based algorithm to estimate flatness-related parameters. The individual elements of the proposed framework are implemented in the form of computational tools, and a set of experiments are conducted on thin-walled parts. It has been observed that the static deflections of the thin-walled component have considerable influence on flatness error, and the same can be captured effectively using the proposed framework. The study also investigates the effect of inevitable aspects of the thin-walled machining, such as workpiece rigidity and thinning on the flatness error. The findings of the present study aid process planners in devising appropriate machining strategies to manufacture thin-walled components within tolerances specified by the designer.

The Deformation Analysis for Flank Milling of Thin-Walled Rectangle Plate Based on Flexible Force Model

2011 ◽  
Vol 189-193 ◽  
pp. 1555-1561
Author(s):  
Liang Hong Xiao ◽  
Liang Tang ◽  
Zi Hua Hu ◽  
Zheng Kuang ◽  
Ju Long Yuan
Keyword(s):  
End Milling ◽  
Simulation Method ◽  
Flank Milling ◽  
Deformation Analysis ◽  
Force Model ◽  
Machining Quality ◽  
Finite Element Numerical Simulation ◽  
Thin Walled ◽  
Experimental Values

By considering the effects of flank milling deformation on machining quality of thin-walled rectangle plate, the flexible force model of spiral end milling is built on the condition that the influence of part/tool on milling is considered with FE (finite element) numerical simulation method in this paper. Based on the flexible force model, the distribution curve of machining deformation is got by the FE prediction for the flank milling of the thin-walled rectangle plate, and the compensation strategy of CL (cutting location) is established. Some contrast tests between the flexible force model, the deflection simulation and error compensation values to the rigid force model and experimental values of flank milling are performed, respectively. The results indicate that both the flexible force model founded in the paper and the analyzed values of flank milling deflection of thin-walled rectangle plate are reliable, and an effective judgment is provided to advance the machining quality of thin-walled parts.

scholarly journals Crowd Evacuation Guidance Based on Combined Action Reinforcement Learning

Algorithms ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 26
Author(s):  
Yiran Xue ◽  
Rui Wu ◽  
Jiafeng Liu ◽  
Xianglong Tang
Keyword(s):  
Reinforcement Learning ◽  
Guidance System ◽  
Force Model ◽  
Interactive Simulation ◽  
Social Force ◽  
Novel Approach ◽  
Learning Agent ◽  
Network Output ◽  
Combined Action ◽  
Crowd Evacuation

Existing crowd evacuation guidance systems require the manual design of models and input parameters, incurring a significant workload and a potential for errors. This paper proposed an end-to-end intelligent evacuation guidance method based on deep reinforcement learning, and designed an interactive simulation environment based on the social force model. The agent could automatically learn a scene model and path planning strategy with only scene images as input, and directly output dynamic signage information. Aiming to solve the “dimension disaster” phenomenon of the deep Q network (DQN) algorithm in crowd evacuation, this paper proposed a combined action-space DQN (CA-DQN) algorithm that grouped Q network output layer nodes according to action dimensions, which significantly reduced the network complexity and improved system practicality in complex scenes. In this paper, the evacuation guidance system is defined as a reinforcement learning agent and implemented by the CA-DQN method, which provides a novel approach for the evacuation guidance problem. The experiments demonstrate that the proposed method is superior to the static guidance method, and on par with the manually designed model method.

Development of Analytical Force Model for End Milling of Magnesium Matrix Composites

2020 ◽  
Author(s):  
Nishita Anandan ◽  
M. Ramulu
Keyword(s):  
End Milling ◽  
Coefficient Of Thermal Expansion ◽  
Cutting Edge ◽  
Force Model ◽  
Matrix Composites ◽  
Magnesium Metal ◽  
Magnesium Matrix Composites ◽  
The Matrix ◽  
Thrust Forces ◽  
Good Agreement

Abstract An analytical approach to predict the cutting forces in end milling of magnesium metal matrix composite is presented in this study. The model was developed by identifying three events that occur when the cutting edge encounters the composite, when an element of the cutting edge encounters just the particles, it may fracture the particle, when the element encounters pure ductile matrix, plastic deformation occurs and when the element is in contact with both the particle and matrix, particle debonding occurs due to mismatch in coefficient of thermal expansion. The probability of these events was estimated using the particle concentration and the distribution in the matrix. A cutting force model is developed by considering the stresses and forces experienced by the cutting edge contributed by these events. The predicted feed forces and the measured forces are in good agreement for most of the cutting conditions. While, the predictive thrust forces were found to diverge at higher feed of 1 mm/rev.

Relative consumption, relative wealth, and long-run growth: when and why is the standard analysis prone to incorrect conclusions?

2021 ◽  
pp. 1-25
Author(s):  
Franz X. Hof ◽  
Klaus Prettner
Keyword(s):  
Growth Rate ◽  
Traditional Approach ◽  
Total Change ◽  
Relative Consumption ◽  
Fundamental Factor ◽  
Elasticity Of Intertemporal Substitution ◽  
Relative Wealth ◽  
Novel Approach ◽  
Long Run ◽  
Two Parameters

Abstract We employ a novel approach for analyzing the effects of relative consumption and relative wealth preferences on economic growth. In the pertinent literature, these effects are usually assessed by examining the dependence of the growth rate on the two parameters of the utility function that seem to measure the strength of the relative consumption and the relative wealth motives. Applying our fundamental factor approach, we identify specifications in which the traditional approach yields incorrect qualitative conclusions. The problematic specifications have the common unpleasant property that the parameter that seems to determine the strength of the relative consumption motive actually also affects the elasticity of intertemporal substitution of absolute consumption (and the strength of the relative wealth motive). Since the standard approach is unaware of the additional effect(s), it attributes the total change in the growth rate incorrectly to the change in the strength of the relative consumption motive.

Simulation of Thin-Walled Parts End Milling with Fluid Jet Support

2020 ◽  
pp. 380-389
Author(s):  
Serhii Kononenko ◽  
Sergey Dobrotvorskiy ◽  
Yevheniia Basova ◽  
Ludmila Dobrovolska ◽  
Vitalii Yepifanov
Keyword(s):  
End Milling ◽  
Thin Walled

Research on Milling Force in Ultrasonic Assisted End Milling of Titanium Alloy Thin-Walled Parts

2018 ◽  
Vol 764 ◽  
pp. 252-260
Author(s):  
Feng Jiao ◽  
Cheng Lin Yao ◽  
Li Zhao ◽  
Feng Qi
Keyword(s):  
Titanium Alloy ◽  
Cutting Force ◽  
Ultrasonic Vibration ◽  
End Milling ◽  
Signal To Noise Ratio ◽  
Milling Force ◽  
Alloy Material ◽  
Ultrasonic Assisted ◽  
Thin Walled ◽  
Force Characteristics

Hard machinability of titanium alloy material and poor stiffness of thin-walled part restricted the extensive applications of titanium alloy thin-walled component in aerospace engineering. In order to increase geometric accuracy, a method of ultrasonic vibration assisted (UVA) end milling technology with workpiece vibrating in feeding direction was put forward in this paper, and the corresponding milling force characteristics in UVA milling of titanium alloy TC4 thin-walled workpiece were researched. Through theoretical analysis, the path of cutter tooth in UVA milling was analyzed. The important factors that affect milling force are obtained with the signal to noise ratio analysis. Results show that the radial cutting force in UVA milling is smaller than that in traditional milling. Cutting force fluctuate in high frequency when treated ultrasonic vibration. And the axial cutting feed is the core factor that affects the milling force. The research provides a certain reference for the precision milling of titanium alloy thin-walled parts.

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