Operational stability prediction in milling based on impact tests

Kiss, Adam K.; Hajdu, Dávid; Bachrathy, Dániel; Stépàn, Gábor

doi:10.1016/j.ymssp.2017.10.019

Cited by 40 publications

(12 citation statements)

References 38 publications

(53 reference statements)

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“…Although much larger amplitude is expected for chatter than for the stationary cutting state, this property cannot always be used for the direct ) is presented in (a,b). Bistability is triggered by a hammer blow similarly [68,70] in (c), while the rooftop measurement is presented in (d) [46]. (Online version in colour.…”

Section: Revealing Unsafe Zone In Milling Processesmentioning

confidence: 99%

See 1 more Smart Citation

Experimental observations on unsafe zones in milling processes

Dombóvári

Iglesias²,

Molnár

et al. 2019

Phil. Trans. R. Soc. A.

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The unsafe zone in machining is a region of the parameter space where steady-state cutting operations may switch to regenerative chatter for certain perturbations, and vice versa. In the case of milling processes, this phenomenon is related to the existence of an unstable quasi-periodic oscillation, the in-sets of which limit the basin of attraction of the stable periodic motion that corresponds to the chatter-free cutting process. The mathematical model is a system of time-periodic nonlinear delay differential equations. It is studied by means of a nonlinear extension of the semidiscretization method, which enables the estimation of the parameter ranges where the unsafe (also called bistable) zones appear. The theoretical results are checked with thorough experimental work: first, step-by-step parameter variations are adapted to identify hysteresis loops, then harmonic burst excitations are used to estimate the extents of the unsafe zones. The hysteresis loops are accurately distinguished from the dynamic bifurcation phenomenon that is related to the dynamic effect of slowly varying parameters. The experimental results confirm the existence of the bistable parameter regions. This article is part of the theme issue ‘Nonlinear dynamics of delay systems’.

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Section: Revealing Unsafe Zone In Milling Processesmentioning

confidence: 99%

“…is presented in (a,b). Bistability is triggered by a hammer blow similarly[68,70] in (c), while the rooftop measurement is presented in (d)[46]. (Online version in colour.…”

mentioning

confidence: 99%

Experimental observations on unsafe zones in milling processes

Dombóvári

Iglesias²,

Molnár

et al. 2019

Phil. Trans. R. Soc. A.

Self Cite

View full text Add to dashboard Cite

show abstract

“…Minimization of tool vibration is one of the main challenges in conventional sized milling processes because inappropriate vibration (chatter) often results in accelerated tool wear or poor surface quality [130][131][132]. In addition to these difficulties, chatter may cause tool breakage in micro-milling [82,133].…”

Section: Vibrations In Micro-millingmentioning

confidence: 99%

A review on micro-milling: recent advances and future trends

Balázs

Geier

Takács

et al. 2020

Int J Adv Manuf Technol

104

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Recently, mechanical micro-milling is one of the most promising micro-manufacturing processes for productive and accurate complex-feature generation in various materials including metals, ceramics, polymers and composites. The micro-milling technology is widely adapted already in many high-tech industrial sectors; however, its reliability and predictability require further developments. In this paper, micro-milling related recent results and developments are reviewed and discussed including micro-chip removal and micro-burr formation mechanisms, cutting forces, cutting temperature, vibrations, surface roughness, cutting fluids, workpiece materials, process monitoring, micro-tools and coatings, and process-modelling. Finally, possible future trends and research directions are highlighted in the micro-milling and micro-machining areas.

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“…This lengthy process could be accepted during the fine-tuning of the milling operation, but it is not feasible in mass production; the modal parameters can change slowly in time by the ageing of the components, or simply by using a new tool. Modal testing during the cutting process presents additional challenges [32], since, in case of traditional modal testing, the Frequency Response Function (FRF) can be determined from the response of impulse excitation induced by a modal hammer [33]. However, during the hammer excitation of thin-walled workpieces, the so-called multiple-hitting (prall) phenomenon can easily occur causing non-ideal input force, which should be avoided.…”

Section: Introductionmentioning

confidence: 99%

In-Process Monitoring of Changing Dynamics of a Thin-Walled Component During Milling Operation by Ball Shooter Excitation

Bachrathy

Kossa

Berezvai

et al. 2020

JMMP

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During the milling of thin-walled workpieces, the natural frequencies might change radically due to the material removal. To avoid resonant spindle speeds and chatter vibration, a precise knowledge of the instantaneous modal parameters is necessary. Many different numerical methods exist to predict the changes; however, small unmodelled effects can lead to unreliable results. The natural frequencies could be measured by human experts based on modal analysis for an often interrupted process; however, this method is not acceptable during production. We propose an online measurement method with an automatic ball shooter device which can excite a wide frequency range of the flexible workpiece. The method is presented for the case of blade profile machining. The change of the natural frequencies is predicted based on analytical models and finite element simulations. The measurement response for the impulse excitation of the ball shooter device is compared to the results of impulse modal tests performed with a micro hammer. It is shown that the ball shooter is capable of determining even the slight variation of the natural frequencies during the machining process and of distinguishing the slight change caused by different clamping methods. An improved FE model is proposed to include the contact stiffness of the fixture.

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Operational stability prediction in milling based on impact tests

Cited by 40 publications

References 38 publications

Experimental observations on unsafe zones in milling processes

Experimental observations on unsafe zones in milling processes

A review on micro-milling: recent advances and future trends

In-Process Monitoring of Changing Dynamics of a Thin-Walled Component During Milling Operation by Ball Shooter Excitation

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