Comparsion of Machining Stability of Up and Down Milling

2013 ◽  
Vol 680 ◽  
pp. 369-386
Author(s):  
Te Ching Hsiao ◽  
J.J. Junz Wang
Keyword(s):  
Milling Process ◽  
One Dimension ◽  
Depth Of Cut ◽  
Two Dimension ◽  
Feed Direction ◽  
Radial Depth ◽  
Dimension 2 ◽  
The Stability ◽  
Time Invariant ◽  
Function Matrix

The purpose of this research is to discuss the machining stability in of the up and down milling of three milling systems: 1) the feed-direction one-dimension, 2) the normal-to-feed-direction one-dimension and 3) the symmetric two-dimension milling systems. A simplified model with time-invariant parameters is adopted to simulate the milling process. In this model, the elementary cutting function, which represents the trajectory of cutting force for a certain local cutting edge, plays an important role in affecting machining stability of the different cutting configurations. This paper presents an in-depth discussion on the effects of cutting configurations and radial depth of cut on the elementary cutting function, and also on the stability lobes. It is found that the elementary cutting function of one-dimension milling system is a real number, as well as its positive and negative values will lead to totally different chatter features. Most technical literatures focus on the chatter features of positive elementary cutting function, while this research discuss that of both positive and negative ones. On the other hand, for the two-dimension milling system, its machining stability found to be dominated by the eigenvalues of the elementary cutting function matrix. The comparison of machining stability in up and down milling is then analyzed and three conclusions are drawn in this research. Firstly, the feed-direction one-dimension milling system has better machining stability in up milling. Secondly, the normal-to-feed-direction one-dimension milling system has better machining stability in down milling. Thirdly, up and down milling both show the same machining stability in the symmetric two-dimension milling system.

scholarly journals Chatter identification in milling of Inconel 625 based on recurrence plot technique and Hilbert vibration decomposition

2018 ◽  
Vol 148 ◽  
pp. 09003 ◽  
Author(s):  
Paweł Lajmert ◽  
Rafał Rusinek ◽  
Bogdan Kruszyński
Keyword(s):  
Stability Limit ◽  
Recurrence Plot ◽  
Milling Process ◽  
Machining Process ◽  
Inconel 625 ◽  
Depth Of Cut ◽  
Force Measurements ◽  
Stability Lobe ◽  
Theoretical Finding ◽  
The Stability

In the paper a cutting stability in the milling process of nickel based alloy Inconel 625 is analysed. This problem is often considered theoretically, but the theoretical finding do not always agree with experimental results. For this reason, the paper presents different methods for instability identification during real machining process. A stability lobe diagram is created based on data obtained in impact test of an end mill. Next, the cutting tests were conducted in which the axial cutting depth of cut was gradually increased in order to find a stability limit. Finally, based on the cutting force measurements the stability estimation problem is investigated using the recurrence plot technique and Hilbert vibration decomposition method.

Tool life prediction by RSM for cryogenic milling of inconel 718

2019 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Nurul Hayati Binti Abdul Halim ◽  
Che Hassan Che Haron ◽  
Jaharah A. Ghani ◽  
Muammar Faiq Azhar
Keyword(s):  
Tool Life ◽  
Inconel 718 ◽  
High Speed ◽  
Metal Cutting ◽  
Milling Process ◽  
Average Error ◽  
Depth Of Cut ◽  
Content Type ◽  
Radial Depth ◽  
Ball Nose Milling

Purpose The purpose of this study is to present the tool life optimization of carbide-coated ball nose milling inserts when high-speed milling of Inconel 718 under cryogenic CO2 condition. The main aims are to analyze the influence level of each cutting parameter on the tool life and to identify the optimum parameters that can lengthen the tool life to the maximum. Design/methodology/approach The experimental layout was designed using Box–Behnken RSM where all parameters were arranged without combining their highest and lowest values of each factor at the same time. A total of 29 milling experiments were conducted. Then, a statistical analysis using ANOVA was conducted to identify the relationship between the controlled factors on tool life. After that, a predictive model was developed to predict the variation of tool life within the predetermined parameters. Findings Results from the experimental found that the longest tool life of 22.77 min was achieved at Vc: 120 m/min, fz: 0.2 mm/tooth, ap: 0.5 mm and ae: 0.2 mm. ANOVA suggests the tool life of 23.4 min can be reached at Vc: 120.06 m/min, fz: 0.15 mm/tooth, ap: 0.66 mm and ae: 0.53 mm. All four controlled factors have influenced the tool life with the feed rate and radial depth of cut (DOC) as the major contributors. The developed mathematical model accurately represented the tool life at an average error of 8.2 per cent when compared to the actual and predicted tool life. Originality/value These experimental and statistical studies were conducted using Box–Behnken RSM method under cryogenic CO2 condition. It is a proven well-known method. However, the cooling method used in this study is a new technique and its effects on metal cutting, especially in the milling process of Inconel 718, has not yet been explored.

An Approach on Fuzzy and Regression Modeling for Hard Milling Process

2015 ◽  
Vol 813-814 ◽  
pp. 498-504 ◽  
Author(s):  
A. Tamilarasan ◽  
D. Rajamani ◽  
A. Renugambal
Keyword(s):  
Manufacturing Systems ◽  
Metal Removal ◽  
Cutting Temperature ◽  
Cutting Speed ◽  
Milling Process ◽  
Regression Modeling ◽  
Average Error ◽  
Depth Of Cut ◽  
Hard Milling ◽  
Radial Depth

This paper proposes the prediction of cutting temperature, tool wear and metal removal rate using fuzzy and regression modeling techniques for the hard milling process. The feed per tooth, radial depth of cut, axial depth of cut and cutting speed were used as process state variables.The experiements were conducted using RSM based central composite rotatable design methodology. Regression and fuzzy modeling were used to evaluate the input – output relationship in the process. It is interesting to observe that the R2 and average error values for each response are very consistent with small variations were obtained.Also, the confirmation results show that very less relative error varitions. Thus, the developed fuzzy models directly integrated in manufacturing systems to reduce the more computational complexity in the process planning activities.

Active Chatter Suppression in Low Immersion Intermittent Milling Process

2020 ◽  
Vol 142 (10) ◽  
Author(s):  
Le Cao ◽  
Tao Huang ◽  
Da-Ming Shi ◽  
Xiao-Ming Zhang ◽  
Han Ding
Keyword(s):  
Period Doubling ◽  
Milling Process ◽  
Period Doubling Bifurcation ◽  
First Order ◽  
Chatter Suppression ◽  
Stability And Stabilization ◽  
Piecewise Model ◽  
Full Immersion ◽  
The Stability ◽  
Time Invariant

Abstract Chatter in low immersion milling behaves differently from that in full immersion milling, mainly because of the non-negligible time-variant dynamics and the occurrence of period doubling bifurcation. The intermittent and time-variant characteristics make the active chatter suppression based on Lyaponov theorem a non-trivial problem. The main challenges lie in how to deal with the time-variant directional coefficient and how to construct a suitable Lyaponov function so as to alleviate the conservation, as well as the saturation of the controller. Generally, the Lyaponov stability of time-invariant dynamics is more tractable. Hence, in our paper, a first-order piecewise model is proposed to approximate the low immersion milling system as two time-invariant sub-ones that are cyclically switched. To alleviate the conservation, a novel piecewise Lyaponov function is constructed to determine the stability of each subsystem independently. The inequality conditions for determining the stability and stabilization are derived. The validity of the proposed stabilization algorithm to suppress both the hopf and period doubling bifurcation, as well as to reduce the conservation of the controller parameters have been verified.

Optimum Conditions for Variable Pitch Milling

2006 ◽  
Author(s):  
Hassan Fazelinia ◽  
Nejat Olgac
Keyword(s):  
Metal Removal ◽  
Linear Time ◽  
Removal Rate ◽  
Optimization Procedure ◽  
Milling Process ◽  
Depth Of Cut ◽  
Variable Pitch ◽  
Linear Time Invariant ◽  
Characteristic Roots ◽  
Time Invariant

From the perspective of regenerative chatter, variable-pitch milling process offers a mathematically very challenging task. It can be reduced to the problem of stability assessment on a linear time-invariant dynamics (LTI) which has more than one independent delays. This mathematically notorious problem is uniquely solved by a recent paradigm. It is called Cluster Treatment of Characteristic Roots (CTCR). This paper presents a process optimization procedure using CTCR over a special milling operation with variable pitch cutters. The optimization is based on maximizing the metal removal rate while avoiding the onset of chatter, which, in turn, enables production of the parts with a desirable surface quality. The end result is a powerful tool to determine some important geometrical and operational features of the process: (i) the pitch angle selection on the tool (i.e., variable pitch cutter vs. uniform pitch cutter), (ii) the optimum cutting conditions (i.e., depth of cut and the spindle speeds).

On the Investigation of Machine Tool Chatter in the Milling Process

2007 ◽  
Author(s):  
Mahsa Moghaddas ◽  
Mohammad H. Ghaffari Saadat
Keyword(s):  
Milling Process ◽  
Depth Of Cut ◽  
Non Linear Equation ◽  
Stability And Instability ◽  
Machine Tool Chatter ◽  
Stability Chart ◽  
Periodic Delay ◽  
The Stability ◽  
Two Parameters ◽  
Delay Differential

In this paper, the chatter phenomenon is investigated through a single degree of freedom model of the milling process. In this regard, the non-linear equation of motion obtained from modeling of the milling process, which is a time-periodic delay differential equation, is simulated, and by changing the parameters: spindle speed and depth of cut, and assuming constant quantities for other parameters of the system the stable and instable points for the system are gained according to these two parameters by numerical method. In the end, the stability chart for this system is plotted and the approximate boundaries between the stability and instability regions are obtained numerically.

Stability Analysis for the Milling of Lateral Walls

2011 ◽  
Vol 346 ◽  
pp. 190-196
Author(s):  
Ai Jun Jiang ◽  
Kai Wu
Keyword(s):  
Three Dimensional ◽  
Depth Of Cut ◽  
Milling Cutter ◽  
Milling Parameters ◽  
Stability Lobes ◽  
Radial Depth ◽  
Stability Model ◽  
The Stability ◽  
Stable Zone ◽  
Lateral Walls

The stability model was established and the two-dimensional and three-dimensional lobes were plotted for the milling of lateral walls in order to avoid chatter occurring in the milling of lateral walls. The combination of milling parameters of free chatter can be selected in the stable zone of stability lobes. The stability of milling lateral walls influenced by radial depth of cut and teeth number of the milling cutter was analyzed. It is shown that the stable zone of stability lobes expands gradually as the spindle speed increases. The stable zone become wider as the radial depth of cut increases. The axial depth of cut limits is increased and higher productivity can be obtained as the teeth of the milling cutter decreases.

Study on Surface Roughness in Micro End Milling of Mold Material

2011 ◽  
Vol 325 ◽  
pp. 594-599 ◽  
Author(s):  
Hiroo Shizuka ◽  
Koichi Okuda ◽  
Masayuki Nunobiki ◽  
Yasuhito Inada
Keyword(s):  
Surface Roughness ◽  
End Milling ◽  
Milling Process ◽  
Cutting Conditions ◽  
Mold Material ◽  
Depth Of Cut ◽  
Milling Operations ◽  
Radial Depth ◽  
Micro End Milling ◽  
End Milling Process

The effects of cutting conditions on the surface roughness in a micro-end-milling process of a mold material are described in this paper. Micro-end-milling operations were performed under different cutting conditions such as feed rate and depth of cut, in order to investigate the factors that had the greatest influence on the finished surface during micro-end-milling. It was revealed that the surface roughness begins to deteriorate when the radial depth of the cut exceeds the tool radius. In addition, it was found that this phenomenon is peculiar to micro-end-milling processes.

Autoresonant Tuning and Control in Ultrasonic Vibration Assisted Drilling Process

2006 ◽  
Vol 505-507 ◽  
pp. 823-828 ◽  
Author(s):  
Yu Chieh Chen ◽  
Yunn Shiuan Liao ◽  
J.D. Fan
Keyword(s):  
Cutting Parameters ◽  
Milling Process ◽  
Performance Characteristics ◽  
Depth Of Cut ◽  
Drilling Process ◽  
Side Milling ◽  
Relational Analysis ◽  
Radial Depth ◽  
Grey Relational ◽  
Optimal Cutting Parameters

This paper presents an optimal cutting-parameter design of heavy cutting in side milling for SUS304 stainless steel. The orthogonal array with relational analysis is applied to optimize the side milling process with multiple performance characteristics. A grey relational grade obtained from the grey relational analysis is used as a performance index to determine the optimal cutting parameters. The selected cutting parameters are cutting speed, feed per tooth, axial depth of cut, and radial depth of cut, while the considered performance characteristics are tool life and metal removal rate. Experimental results have shown that cutting performance in the side milling process for heavy cutting can be significantly improved through this approach.

Physical Simulation of the Cutting Process Induced by Tool Geometric Angle and Cutting Parameters

2012 ◽  
Vol 430-432 ◽  
pp. 715-718 ◽  
Author(s):  
Xue Hui Wang ◽  
Ping Zhou ◽  
Ya Wen Liu ◽  
Ming Jun Dai
Keyword(s):  
Physical Simulation ◽  
Cutting Parameters ◽  
Simulation Method ◽  
Helix Angle ◽  
Rake Angle ◽  
Milling Process ◽  
Cutting Process ◽  
Depth Of Cut ◽  
Radial Depth ◽  
Solid Carbide

The tool geometric angle and cutting parameters have a significant influence on the titanium alloy milling process by the usage of solid carbide end mills.The physical simulation method was applied to predict the cutting force and temperature by using two comparative sets of simulation data such as the different tool gemetric angle as tool rake angle, helix angle and different cutting parameters such as spindle speed, axial depth of cut, radial depth of cut. Thus are the commonly used methods to simulate and predict the cutting process before the actual production, which can reduce product cost and time.

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