Analysis of the Influence of Mill Helix Angle on Chatter Stability

Zatarain, Mikel; Muñoa, Jokin; Peigné, Grégoire; Insperger, Tamás

doi:10.1016/s0007-8506(07)60436-3

Cited by 121 publications

(66 citation statements)

References 9 publications

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“…For this example, the region of instability around 1400rpm, 2mm is clearly an isolated island of instability due to secondary Hopf bifurcations. Again, this is in contrast to the period doubling islands of instability described by Patel [23] and Zatarain [33].…”

Section: Results: Variable Helix Toolscontrasting

confidence: 59%

“…This is a useful result since the semi-discretisation predictions required axial discretisation of the tool, and yet they agree closely with an experimentally validated model that did not require axial discretisation. It should be noted that these islands of instability arising due to period doubling bifurcations were first observed by Zatarain et al [33].…”

Section: Lower Radial Immersionsmentioning

confidence: 72%

“…Patel [23] and Zatarain [33] which are associated with period doubling bifurcations rather than secondary Hopf bifurcations. The time-averaged semi-discretisation prediction agrees reasonably closely with the semi-discretisation prediction, but can only predict the existence of secondary Hopf bifurcations.…”

Section: Results: Variable Helix Toolsmentioning

confidence: 99%

See 2 more Smart Citations

Analytical prediction of chatter stability for variable pitch and variable helix milling tools

Sims

Mann

Huyanan

2008

Journal of Sound and Vibration

177

120

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Regenerative chatter is a self-excited vibration that can occur during milling and other machining processes. It leads to a poor surface finish, premature tool wear, and potential damage to the machine or tool. Variable pitch and variable helix milling tools have been previously proposed to avoid the onset of regenerative chatter. Although variable pitch tools have been considered in some detail in previous research, this has generally focussed on behaviour at high radial immersions. In contrast there has been very little work focussed on predicting the stability of variable helix tools. In the present study, three solution processes are proposed for predicting the stability of variable pitch or helix milling tools.The first is a semi-discretisation formulation that performs spatial and temporal discretisation of the tool. Unlike previously published methods this can predict the stability of variable pitch or variable helix tools, at low or high radial immersions.The second is a time-averaged semi-discretisation formulation that assumes time-averaged cutting force coefficients. Unlike previous work, this can predict stability of variable helix tools at high radial immersion.The third is a temporal-finite element formulation that can predict the stability of variable pitch tools with a constant uniform helix angle, at low radial immersion.

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Section: Results: Variable Helix Toolscontrasting

confidence: 59%

Section: Lower Radial Immersionsmentioning

confidence: 72%

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Analytical prediction of chatter stability for variable pitch and variable helix milling tools

Sims

Mann

Huyanan

2008

Journal of Sound and Vibration

177

120

View full text Add to dashboard Cite

show abstract

“…What is more, these methods can take into account several nonlinearities as the variation of the modal parameters of the system, or the variation of the geometry or the cutting coefficients of the tool. Zatarain et al determined the influence of the helix angle in the milling of flexible systems with an axial depth of cut above the helix height divided by the number of tooth of the tool [15].…”

Section: Introductionmentioning

confidence: 99%

Chatter avoidance in the milling of thin floors with bull-nose end mills: Model and stability diagrams

Campa

Lacalle

Celaya

2011

International Journal of Machine Tools and Manufacture

120

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The milling of thin parts is a high added value operation where the machinist has to face the chatter problem. The study of the stability of these operations is a complex task due to the changing modal parameters as the part losses mass during the machining and the complex shape of the tools that are used. The present work proposes a methodology for chatter avoidance in the milling of flexible thin floors with a bull-nose end mill. First, a stability model for the milling of compliant systems in the tool axis direction with bullnose end mills is presented. The contribution is the averaging method used to be able to use a linear model to predict the stability of the operation. Then, the procedure for the calculation of stability diagrams for the milling of thin floors is presented. The method is based on the estimation of the modal parameters of the part and the corresponding stability lobes during the machining. As in thin floor milling the depth of cut is already defined by the floor thickness previous to milling, it is proposed the use of stability diagrams that relate the tool position along the tool-path with the spindle speed. Hence, the sequence of spindle speeds that the tool must have during the milling can be selected. Finally, this methodology has been validated by means of experimental tests.

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“…where l p = Dπ / (N tan β) is the helix pitch [8]. The entrance and exit immersion angles depend on the direction of rotation of the tool.…”

Section: Mechanical Modelmentioning

confidence: 99%

On the Effect of Distributed Regenerative Delay on the Stability Lobe Diagrams of Milling Processes

Molnár

Insperger

2015

Period. Polytech. Mech. Eng.

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Regenerative machine tool chatter is investigated for milling operations with helical tools. The stability of a two-degreesof-freedom milling model is analyzed IntroductionThe occurrence of harmful vibrations (chatter) during metal cutting processes is an important problem in manufacturing technology. Machine tool chatter has many unfavorable effects: it reduces the productivity and the surface quality, causes noise, enhances tool wearing, and even leads to tool damage in some cases. Therefore, avoiding or suppressing chatter is highly important for the machine tool industry. In the past few decades, a significant amount of research was conducted to find the governing physical phenomena behind chatter in order to understand its nature and describe methods to avoid or suppress it.One of the most widely accepted explanations of machine tool chatter is the theory of surface regeneration introduced by Tobias [1] and Tlusty [2]: the vibrating tool leaves a wavy surface behind, which results in a varying cutting-force in the consecutive cut. Accordingly, delay effects appear in the models of metal cutting operations since the cutting-force exciting the tool motion is determined by the chip thickness, which depends both on the actual tool position and the delayed position at the previous cut. Hence, machine tool vibrations can be described using delay-differential equations, and the regenerative machine tool chatter can be considered as the manifestation of self-excited oscillations in a time-delay system.Following the works of Tobias and Tlusty, a large effort has been put lately into the more accurate modeling of machine tool chatter. In this paper we follow the model of [3], where the stability of turning processes is investigated taking the distribution of the cutting force along the tool's rake face into account. The concept was experimentally verified in [4]. Extension to interrupted turning operation was presented in [5]. Here, we will extend the distributed cutting-force model to milling processes and perform the stability analysis.The outline of the paper is the following. Section 2 presents the mechanical model of the system, the description of the cutting-force expression, and the final form of the governing equation. In Section 3, the semi-discretization technique [6] is applied to analyze the stability of the system numerically. Some numerical issues regarding computational efficiency are also highlighted. Section 4 considers the special cases of the

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Analysis of the Influence of Mill Helix Angle on Chatter Stability

Cited by 121 publications

References 9 publications

Analytical prediction of chatter stability for variable pitch and variable helix milling tools

Analytical prediction of chatter stability for variable pitch and variable helix milling tools

Chatter avoidance in the milling of thin floors with bull-nose end mills: Model and stability diagrams

On the Effect of Distributed Regenerative Delay on the Stability Lobe Diagrams of Milling Processes

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