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.

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.

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.

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.

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.

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.

The Effect of Harmonic Force Components on Regenerative Stability in End Milling

Manufacturing ◽  
2003 ◽  
Author(s):  
J.-J. Junz Wang ◽  
C. M. Zheng ◽  
C. Y. Huang
Keyword(s):  
End Milling ◽  
Helix Angle ◽  
Milling Process ◽  
Fourier Series Expansion ◽  
Harmonic Force ◽  
Average Force ◽  
Dynamic Forces ◽  
Force Components ◽  
The Stability ◽  
Milling Forces

In a systematic manner, this paper investigates the effects of harmonic force components on the regenerative stability of an end milling process. By representing the milling force pulsation in a Fourier series expansion form, the dynamic force components and the average forces due to bi-directional dynamic feed rates are both included in the generalized system dynamics formulation. In the resulting expression for the stability criterion, the spectral features of the milling forces are integrated with the dynamics of the structure, showing the significance or insignificance of the dynamic components of the milling forces in affecting the stability of the milling process. Key system parameters discussed include the magnitude of the average and harmonic forces, the cutter helix angle and the spindle speed. It is shown that a low helix angle and a smaller number of cutting flutes increase the effect of dynamic forces on the system stability. The significance of the harmonic forces is exemplified by the special cutting conditions where the average force becomes zero and the stability limits would be infinite as predicted by models using the average force alone. Improvements in the accuracy of stability lobes resulting from the inclusion of the dynamic forces and the validity of the presented model in general will be illustrated by numerical simulation and verified by experiments as well as by comparison with published results.

Dynamics of Drill Bits With Cutting Edges of Varying Parameters

2013 ◽  
Author(s):  
Zoltan Dombovari ◽  
Gabor Stepan
Keyword(s):  
Metal Cutting ◽  
Helix Angle ◽  
Milling Process ◽  
Drilling Process ◽  
Deep Drilling ◽  
Stability Properties ◽  
Stability Diagrams ◽  
Drill Bits ◽  
Variable Helix ◽  
The Stability

In the metal cutting industry it is well known that milling processes can be stabilized by applying different strategies in order to destroy the pure single delay regeneration that arise in case of conventional milling tools when high material removal rates are used either at low or at high cutting speeds. To achieve this goal, variable pitch angle, variable helix angle and serrated tools are already available in the market and serve alternative solutions for process designers to enhance milling process stability. Regeneration can occur and can cause instability on the tip of the deep drilling equipment when the drill bit is driven across hard earth crust materials. This work shows that theories introduced for milling processes can be implemented to improve the stability properties of deep drilling processes, too. Unlike in case of most milling processes, however, the stability properties of deep drilling are affected by the longitudinal and the torsional vibration modes. In this paper, the geometrical and mechanical models are derived for drill bits with general shapes of cutting edges and it is shown that the two DOF dynamics can be described by distributed state dependent delay differential equations. The stability properties are characterized in stability diagrams that can help to select the optimal drilling process parameters.

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.

Basic Experimental and Numerical Investigations on Chip Pressing

2013 ◽  
Vol 554-557 ◽  
pp. 630-637 ◽  
Author(s):  
Martin Grüner ◽  
Marion Merklein
Keyword(s):  
Numerical Simulation ◽  
Aluminium Alloys ◽  
Testing Machine ◽  
Material Model ◽  
Extrusion Process ◽  
Milling Process ◽  
Numerical Investigations ◽  
Compression Direction ◽  
Universal Testing ◽  
The Stability

Aluminium alloys show a great potential for lightweight constructions due to their high strength and low density but the production of this material is very energy consuming. Also the recycling of aluminium alloys, e.g. chips from the milling process, shows different challenges. Beside contamination by cooling lubricant and oxidation of the surface of the chips the melting and rolling process for new semi finish products needs a high amount of energy. TEKKAYA shows a new approach for recycling of aluminium alloy chips by an extrusion process at elevated temperatures producing different kinds of profiles. A new idea is the production of components directly out of chips using severe plastic deformation for joining of the chips similar to the accumulative roll bonding process in sheet metal forming. In a first approach aluminium alloy chips out of a milling process were uniaxial compressed with different loads inside an axisymmetric tool installed in a universal testing machine. The compressed chip disks subsequently were tested with two experiments to gain information on their stability. First experiment is a disk compression test with the disk standing on its cylindrical surface, giving information on the stability perpendicular to the compression direction. Second experiment is a stacked disk compression test with three disks to investigate the stability parallel to compression direction. During all three tests force and displacement values are recorded by the universal testing machine. These data are also processed to calculate or identify input parameters for the numerical investigations. For numerical simulation ABAQUS in conjunction with the Drucker-Prager-Cap material model, which is often used for sintering processes, seems to be a good choice. By numerical simulation of the experiments and comparison with the experiments input parameters for the material model can be identified showing good accordance. This material model will be used in future numerical investigations of an extrusion process to identify tool geometries leading to high strains inside the material and by this to an increased stability of the parts.

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