scholarly journals Stability Prediction of Milling Process with Variable Pitch Cutter

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Gang Jin ◽  
Qichang Zhang ◽  
Shuying Hao ◽  
Qizhi Xie
Keyword(s):  
Helix Angle ◽  
Milling Process ◽  
Depth Of Cut ◽  
Force Model ◽  
Stable Limit ◽  
Variable Pitch ◽  
Tool Geometries ◽  
Piecewise Continuous ◽  
The Stability ◽  
New Phenomena

The use of variable pitch cutter is a known means to increase the stable limit depth of cut by disrupting the regenerative effect. In this paper, an improved semidiscretization algorithm is presented to predict the stability lobes for variable pitch cutters. Modeling efforts develop a straightforward analytical integral force model that can cover any case of piecewise continuous cutting regions regarding the helix angle. The proposed approach has been verified with the comparisons with prior works, time domain simulations, and cutting tests. In addition, the method is also applied to examine the effect of the tool geometries on the stability trends for variable pitch milling. Some new phenomena for certain combinations of parameters are shown and explained.

Stability prediction of milling process with variable pitch and variable helix cutters

2013 ◽  
Vol 228 (2) ◽  
pp. 281-293 ◽  
Author(s):  
Gang Jin ◽  
Qichang Zhang ◽  
Shuying Hao ◽  
Qizhi Xie
Keyword(s):  
Helix Angle ◽  
Milling Process ◽  
Force Model ◽  
Stability Prediction ◽  
Chatter Vibration ◽  
Variable Pitch ◽  
Tool Geometries ◽  
Variable Helix ◽  
Piecewise Continuous ◽  
The Stability

The use of variable pitch or helix cutters is a known means to prevent chatter vibration during milling. In this article, an alternative method based on an improved semi-discretization method is proposed to predict the stability of variable pitch or variable helix milling. In order to consider the effect of distributed system delays attributed to helix variation, the average delays were calculated for each flute after the engaged cutting flutes were divided into a finite number of axial elements. Meanwhile, a straightforward integral force model, which can consider the piecewise continuous regions of the cutting that describe the helix angle is used to determine the cutting force. Through comparisons with prior works, time-domain simulations, and cutting tests, the proposed approach was verified. In addition, the method was applied to examine the effect of tool geometries on stability trends. Several phenomena for certain combinations of pitch and helix angles are shown and explained.

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.

A Generalized Runge-Kutta Method for Stability Prediction of Milling Operations With Variable Pitch Tools

2014 ◽  
Author(s):  
Jinbo Niu ◽  
Ye Ding ◽  
Limin Zhu ◽  
Han Ding
Keyword(s):  
Helix Angle ◽  
Depth Of Cut ◽  
Multiple Delays ◽  
Machining Parameters ◽  
Kutta Method ◽  
Computational Accuracy ◽  
Variable Pitch ◽  
Runge Kutta Method ◽  
Runge Kutta ◽  
The Stability

This paper extends the generalized Runge-Kutta method (GRKM) to predict the machining stability of milling systems with variable-pitch tools. Different from the uniform cutters with fixed pitch angles, the variation of tooth distribution angles of variable pitch cutters significantly affects the stability diagrams of the milling systems. From the viewpoint of the regenerative chatter, the milling system with non-uniform tools is governed by a delayed differential equation (DDE) with multiple delays. Afterwards, the GRKM, an approach verified with high computational accuracy and efficiency for DDEs with a single delay, is extended to tackle the milling systems with multiple delays based on Floquet theory. Besides the pitch angles, other geometry parameters of the cutter are also taken into consideration, such as the helix angle, which is proved with limited influence on the stability lobes. With the objective of maximizing productivity, the resultant stability charts provide valuable reference for the geometry design of variable-pitch cutters and for the choice of machining parameters, i.e. the spindle speed and the depth of cut.

Investigation of Period-Doubling Islands in Milling With Simultaneously Engaged Helical Flutes

2012 ◽  
Vol 134 (2) ◽  
Author(s):  
Firas A. Khasawneh ◽  
Oleg A. Bobrenkov ◽  
Brian P. Mann ◽  
Eric A. Butcher
Keyword(s):  
State Space ◽  
Period Doubling ◽  
Helix Angle ◽  
Milling Process ◽  
Collocation Methods ◽  
Depth Of Cut ◽  
Stability Behavior ◽  
The Stability ◽  
Step Over ◽  
High Depth

This paper investigates the stability of a milling process with simultaneously engaged flutes using the state-space TFEA and Chebyshev collocation methods. In contrast to prior works, multiple flute engagement due to both the high depth of cut and high step-over distance are considered. A particular outcome of this study is the demonstration of a different stability behavior in comparison to prior works. To elaborate, period-doubling regions are shown to appear at relatively high radial immersions when multiple flutes with either a zero or nonzero helix angle are simultaneously cutting. We also demonstrate stability differences that arise due to the parity in the number of flutes, especially at full radial immersion. In addition, we study other features induced by helical tools such as the waviness of the Hopf lobes, the sensitivity of the period-doubling islands to the radial immersion, as along with the orientation of the islands with respect to the Hopf lobes.

Self-Excited Vibrations in a Delay Oscillator: Application to Milling With Simultaneously Engaged Helical Flutes

2009 ◽  
Author(s):  
Firas A. Khasawneh ◽  
Brian P. Mann ◽  
Oleg A. Bobrenkov ◽  
Eric A. Butcher
Keyword(s):  
Period Doubling ◽  
Helix Angle ◽  
Milling Process ◽  
Depth Of Cut ◽  
Frame Work ◽  
Continuous Delay ◽  
The Stability ◽  
Delay Differential ◽  
Step Over ◽  
High Depth

This paper investigates the stability of a milling process with simultaneously engaged flutes by extending the state-space temporal finite elements method. In contrast to prior works, multiple flute engagement due to both a high depth of cut and a high step-over distance are considered. A particular outcome of this study is the development of a frame work to determine the stability of periodic, piecewise continuous delay differential equations. Another major outcome is the demonstration of different stability behavior at the loss of stability in comparison to prior results. To elaborate more, period doubling regions are shown to appear at relatively high radial immersions when multiple flutes with either a zero or non-zero helix angle are simultaneously cutting.

Study on the stability for non-uniform helix angle tools in the milling process

2020 ◽  
Vol 37 (8) ◽  
pp. 387-393
Author(s):  
Qiang Guo ◽  
Ming-Yang Zhang ◽  
Yuan-Shin Lee ◽  
Zhi-Bo Yang ◽  
Yan Jiang ◽  
...  
Keyword(s):  
Helix Angle ◽  
Milling Process ◽  
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.

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.

scholarly journals Stability Analysis of Milling Process with Variable Spindle Speed and Pitch Angle considering Helix Angle and Process Phase Difference

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Gang Jin ◽  
Haotian Jiang ◽  
Jianxin Han ◽  
Zhanjie Li ◽  
Hua Li ◽  
...  
Keyword(s):  
Phase Difference ◽  
Pitch Angle ◽  
High Speed ◽  
Helix Angle ◽  
Stability Domain ◽  
Milling Process ◽  
Spindle Speed ◽  
The Stability ◽  
The Time Domain ◽  
Milling Chatter

Suppression of milling chatter by disrupting regenerative effect is a well-known method to obtain higher cutting stability domain. In this paper, a dynamic model of the milling process with variable spindle speed and pitch angle considering helix angle and process phase difference is presented. Then, an updated semidiscretization method is applied to obtain the stability chart. After the effectiveness of the proposed method is confirmed by comparisons with the previously published works and the time-domain simulations, lots of analyses are conducted to deeply evaluate the influence of the helix angle, the process phase difference, and feed per tooth on milling stability. Results show that the change of helix angle can result in significant stability discrepancies for both high-speed and low-speed regions. Though the process phase difference has the randomness and immeasurability in the practical application, it has an important influence on the stability and will result in a periodic evolution of the stability with a period π. Also, its recommended values are given for the practical milling process.

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).

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