Determination of the stability lobes with multi-delays considering cutter’s helix angle effect for machining process

2016 ◽  
Vol 231 (12) ◽  
pp. 2059-2071 ◽  
Author(s):  
Qiang Guo ◽  
Yuwen Sun ◽  
Yan Jiang ◽  
Yanyan Yan ◽  
Pingmei Ming
Keyword(s):  
Helix Angle ◽  
Machining Process ◽  
Stability Lobes ◽  
Angle Effect ◽  
The Stability

scholarly journals Stability Analysis of Milling Process with Multiple Delays

2020 ◽  
Vol 10 (10) ◽  
pp. 3646 ◽  
Author(s):  
Yonggang Mei ◽  
Rong Mo ◽  
Huibin Sun ◽  
Bingbing He ◽  
Kun Bu
Keyword(s):  
Stability Limit ◽  
Helix Angle ◽  
Milling Process ◽  
Machining Process ◽  
Multiple Delays ◽  
Calculation Time ◽  
Discretization Algorithm ◽  
Cutting Chatter ◽  
Regeneration Effect ◽  
The Stability

Cutting chatter is extremely harmful to the machining process, and it is of great significance to eliminate chatter through analyzing the stability of the machining process. In this work, the stability of the milling process with multiple delays is investigated. Considering the regeneration effect, the dynamics of the milling process with variable pitch cutter is modeled as periodic coefficients delayed differential equations (DDEs) with multiple delays. An adaptive variable-step numerical integration method (AVSNIM) considering the effect of the helix angle is developed firstly, which can discretize the cutting period accurately, thereby improving the calculation accuracy of the stability limit of the milling process. The accuracy and efficiency of the AVSNIM are verified through a benchmark milling model. Subsequently, a novel spindle speed-dependent discretization algorithm is proposed, which is combined with the AVSNIM to further reduce the calculation time of the stability lobes diagram (SLD). The simulation experiment results demonstrate that the proposed algorithm can effectively reduce the calculation time.

Influence of Helix Angle in Low Immersion Milling Forces and Stability Analysis: down-Milling, up-Milling and Slotting

2011 ◽  
Vol 308-310 ◽  
pp. 1565-1570
Author(s):  
Muhammad Masud Akhtar ◽  
Xiang Huang ◽  
Wen Liang Chen ◽  
Zi Xiong Lin
Keyword(s):  
Order Approximation ◽  
Helix Angle ◽  
Good Surface ◽  
Zero Order Approximation ◽  
Stability Lobes ◽  
Good Surface Finish ◽  
The Stability ◽  
Prediction Control ◽  
Milling Forces ◽  
The Impact

Chatter is the most obscuring phenomenon and significant amount of research has been documented regarding prediction, control and elimination of chatter. Chatter is still a main hindrance in achieving good surface finish and productivity. This paper presents the influence of helix angle of milling cutter in down-milling, up-milling and slotting operation. Altintas multi-frequency solution (MFS) is advanced by adding the impact of helix angle in milling forces. A comparison is made for stability lobes diagram based on the helix angle model for different helix angles against the Altintas multi-frequency solution model (MFS) and zero order approximation (ZOA) model. The comparison shows that for small helix angle the stability lobes follow the Altintas (MFS) model and for high helix angle the stability lobes follow the Altintas (ZOA) model. The experimental results prove the simulations. Introduction

scholarly journals Chatter Investigation on Machining of Gray Cast Iron Considering the Damping Effect

2019 ◽  
Vol 7 (3) ◽  
pp. 64
Author(s):  
Everton Ruggeri Silva Araujo ◽  
Giovanni De Souza Pinheiro ◽  
João Álvaro Belo Pantoja Junior ◽  
Salomão Levy Neto
Keyword(s):  
Cast Iron ◽  
Surface Finish ◽  
Gray Cast Iron ◽  
Machining Process ◽  
System Stability ◽  
Gray Cast ◽  
Stability Lobes ◽  
Chatter Vibrations ◽  
Roughness Analysis ◽  
The Stability

In recent years, the study of chatter vibrations has been intensifying in the machining of materials. In this paper an investigation of this phenomena was conducted for gray cast iron (CGI). The chatter vibrations in machining process can considerably compromise the workpiece surface finish, tool wear and in some cases provide severe damage to the machine-tool. Thus there is an imminent need to expand the theory of chatter vibrations for the class of brittle materials. To analyze the vibrations of the process of machining and zones where the process is stable, and where it is unstable, the stability lobes diagram was used. This diagram is constructed at low speed cutting, where the phenomenon of damping arises. The damping is a crucial factor in the process, it increases system stability. This effect was considered in the formulation of chatter vibrations using the indentation model of Wu. For experimental validations the signals of cutting force were acquired and analysis was conducted in frequency domain to identify where the vibrations emerged allied with a roughness analysis of the workpiece. The results demonstrated perfectly the consequences of chatter vibrations in surface finish of grey cast iron and proved that the stability lobes diagram provides good results to detect these vibrations, determining the areas where the material removal should be avoid.

Effect of Cutting Conditions on the Stability Lobes for End Milling Process

2010 ◽  
Vol 139-141 ◽  
pp. 748-751
Author(s):  
Min Wan ◽  
Yi Ting Wang ◽  
Wei Hong Zhang ◽  
Jian Wei Dang
Keyword(s):  
End Milling ◽  
Cutting Parameters ◽  
Helix Angle ◽  
Milling Process ◽  
Cutting Condition ◽  
Multiple Delays ◽  
Cutter Runout ◽  
Stability Lobes ◽  
The Stability ◽  
New Phenomena

Milling process will be dominated by multiple delays due to the effect of the cutter runout or the pitch angles of the cutter. In this paper, research efforts are focused on the dynamic behavior of milling processes under different cutting condition parameters such as different radial immersions, feed directions, feeds per tooth and helix angles. To improve the prediction accuracy of stability lobe, the combined influences of feed rate and cutter runout on the stability lobes are also taken into account. The basic principle of the method presented in one existing work is applied to examine the asymptotic stability trends for both down milling and up milling. Some new phenomena for certain combinations of cutting parameters are shown and explained in detail. It is found that as cutter runout occurs, feed per tooth, feed direction and cutter helix angle have great effects on the stability lobes.

Determination of the stability lobes in milling operations based on homotopy and simulated annealing techniques

Mechatronics ◽  
2014 ◽  
Vol 24 (3) ◽  
pp. 177-185 ◽  
Author(s):  
D. Olvera ◽  
A. Elías-Zúñiga ◽  
H. Martínez-Alfaro ◽  
L.N. López de Lacalle ◽  
C.A. Rodríguez ◽  
...  
Keyword(s):  
Simulated Annealing ◽  
Stability Lobes ◽  
Milling Operations ◽  
The Stability

Multi Frequency Solution of Chatter Stability for Low Immersion Milling

2004 ◽  
Vol 126 (3) ◽  
pp. 459-466 ◽  
Author(s):  
S. D. Merdol ◽  
Y. Altintas
Keyword(s):  
Transfer Function ◽  
Spindle Speed ◽  
Machining Process ◽  
Natural Mode ◽  
Chatter Stability ◽  
Stability Lobes ◽  
The Stability ◽  
Effective Transfer ◽  
Low Radial Immersion ◽  
Chatter Stability Lobes

Finish milling is usually required in the peripheral milling of thin aircraft webs with long end mills, where the structures are flexible and radial depths of cut are small. The spindle speed and depth of cut must be selected optimally to avoid both forced and chatter vibrations, which in turn enables production of the parts within specified tolerances. Recent articles show that stability pockets differ at certain speeds when the radial immersion in milling is low and the machining process is highly intermittent. This paper presents a stability theory which predicts chatter stability lobes that are not covered by classical chatter theories in which the coupling between the spindle speed and process stability are neglected. The dynamics of low radial immersion milling are formulated as an eigenvalue problem, where harmonics of the tooth spacing angle and spread of the transfer function with the harmonics of the tooth passing frequencies are considered. It is shown that the stability lobes are accurately predicted with the presented method. This paper details the physics involved when the tooth passing frequencies alter the effective transfer function of the structure in the stability solution. The products of the harmonics of the directional coefficients and transfer functions of the structure are evaluated at the natural mode under the influence of tooth passing frequency harmonics in order to obtain the exact locations of chatter stability lobes.

Determining the Norton’s Equivalent Model of Distribution System with Distributed Generation (DG) for Stability Analysis

2019 ◽  
Vol 12 (2) ◽  
pp. 190-198
Author(s):  
Sunny Katyara ◽  
Lukasz Staszewski ◽  
Faheem Akhtar Chachar
Keyword(s):  
Distributed Generation ◽  
Normal Condition ◽  
Distribution System ◽  
Distribution Networks ◽  
Equivalent Model ◽  
Stability Factor ◽  
Matlab Simulation ◽  
The Stability ◽  
Stability Issues

Background: Since the distribution networks are passive until Distributed Generation (DG) is not being installed into them, the stability issues occur in the distribution system after the integration of DG. Methods: In order to assure the simplicity during the calculations, many approximations have been proposed for finding the system’s parameters i.e. Voltage, active and reactive powers and load angle, more efficiently and accurately. This research presents an algorithm for finding the Norton’s equivalent model of distribution system with DG, considering from receiving end. Norton’s model of distribution system can be determined either from its complete configuration or through an algorithm using system’s voltage and current profiles. The algorithm involves the determination of derivative of apparent power against the current (dS/dIL) of the system. Results: This work also verifies the accuracy of proposed algorithm according to the relative variations in the phase angle of system’s impedance. This research also considers the varying states of distribution system due to switching in and out of DG and therefore Norton’s model needs to be updated accordingly. Conclusion: The efficacy of the proposed algorithm is verified through MATLAB simulation results under two scenarios, (i) normal condition and (ii) faulty condition. During normal condition, the stability factor near to 1 and change in dS/dIL was near to 0 while during fault condition, the stability factor was higher than 1 and the value of dS/dIL was away from 0.

Synthesis and solvatochromic studies of 2- amino-3-phenolazo1-(4-sulfophenyl)-3-methyi-5-pyrozolone and use it for the determination of trace amount of Nickel (II) in blood samples

2016 ◽  
Vol 5 (10) ◽  
pp. 4920
Author(s):  
Amar M. Ali ◽  
Hussain. J. Mohammed*
Keyword(s):  
Stability Constant ◽  
Trace Amount ◽  
Benzenesulfonic Acid ◽  
Determination Method ◽  
Blood Samples ◽  
Determination Of Nickel ◽  
Normal Human ◽  
The Stability ◽  
Normal Human Blood

A new, simple, sensitive and rapid spectrophotometric method is proposed for the determination of trace amount of Nickel (II). The method is based on the formation of a 1:2 complex with 4-(4-((2-hydroxy-6-nitrophenyl) diazenyl) -3-methyl-5-oxo-2, 5-dihydro-1H-pyrazol-1-yl) benzenesulfonic acid (2-ANASP) as a new reagent is developed. The complex has a maximum absorption at 516 nm and εmax of 1. 84 X 105 L. mol-1. cm-1. A linear correlation (0. 25 – 4. 0μg. ml-1) was found between absorbance at λmax and concentration. The accuracy and reproducibility of the determination method for various known amounts of Nickel (II) were tested. The results obtained are both precise (RSD was 1. 2 %) and accurate (relative error was 0. 787 %). The effect of diverse ions on the determination of Nickel (II) to investigate the selectivity of the method were also studied. The stability constant of the product was 0. 399 X 106 L. mol-1. The proposed method was successfully applied to the analysis of diabetes blood and normal human blood. 

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