Effect Of Tool Vibration Research Articles

The Influence of Machining Variables on the Quality of the Shaping Process on Hard Steel

The product quality of hard steel material formed by a shaping machine using HSS tools was studied under the influence of machining variables. The research focused on the effects of tool vibration on the surface roughness of the product. The experimental process was carried out by selecting the machining independent variables, namely: cutting speed (V) = 1 m/min; 2 m/min; 3 m/min; cutting thickness (a) = 1 mm, 1.5 mm, 2 mm; feeding motion (f) = 5 mm/step; 8mm/step; 10 mm/step. Shaping machine was operated with 3 fixed speed levels (n) of 21.8 rpm, 39 rpm and 59.8 rpm, respectively. The dependent variable, namely stroke per minute (np); and feed rate (Vf). The material used was ASTM A483-A high carbon steel. Vibration measurements were taken during machining using an ADXL 345 accelerometer and an Arduino Pro Mini with support for Arduino IDE 1.8.13 and USB TTL CP 2120 software. Vibration acceleration (af) on the tool was recorded and an evaluation was performed to determine the effects of machining variables on the final products. The results show that speed lavel of machine, feed rate , and cutting thickness majorly affect vibration. The lowest vibration was obtained at a speed (n) of 21.8 rpm, a feed rate (Vf) of 1 mm/s, and cutting thickness (a) of 0.2 mm. The highest vibration was obtained at n of 59.6 rpm, Vf = 1 mm/s and a of 0.4 mm. The quality of the product related to the surface roughness was mainly influenced by the machine speed levels. The roughness values ranged from 3.97 to 6.46 µm, with the lowest surface roughness or smoother surface achieved at a moderate speed of 39 rpm and higher surface roughness at high (59.8 rpm) and low (21.8 rpm) speeds.

Oscillations of Cutting Tool as a Useful Effect in Turning and Drillingm

The paper presents the fixtures with movably mounted turning and drilling cutting tools. The fixtures were developed on the principle of oscillating tooltip similar to the principle of the ultrasonic vibration-assisted machining process. However, presented fixtures do not need an electricity source and utilize mainly forced and self-excited oscillations. In general, the tool vibrations during the cutting process are recognized as a negative phenomenon as it causes a shortening of the tool life and worsens the roughness of the machined surfaces. However, a deeper understanding of the cutting process proposes possible positive effects of tool vibration in terms of chip shapes, flank wear, chip volume coefficient, and quality of the machined surface. Experimentally obtained dependence of mentioned quantities is provided in the paper.

Direct Observation of Discharge Phenomena in Vibration-Assisted Micro EDM of Array Structures.

The batch mode electrical discharge machining (EDM) method has been developed to improve the throughput and accuracy in fabricating array structures, but the process suffers from insufficient debris removal caused by the complex electrode geometry. Tool vibration has been used to improve flushing conditions, but to date the underlying mechanism of the tool vibration on the micro EDM of array structures remains unclear. This study aimed to investigate the effect of tool vibration on the machining process by direct observation of the discharge phenomena in the discharge gap by using a high-speed camera. Micro EDM experiments using 9 and 25 array electrodes were performed, and the effect of tool vibration on the discharge uniformity and tool wear was evaluated. It was found that tool vibration improved the uniformity of the discharge distribution, increased the machining efficiency, and suppressed the tool wear. The discharges occurred in periodic intervals, and the intensity increased with the amplitude of tool vibration. The results of this study indicate that the vibration parameters determine the discharge period duration and intensity to achieve optimum stability and efficiency of the machining process.

GRA based optimization of tool vibration and surface roughness in face milling of hardened steel alloy

In current study, an experimental research has been carried out for the enhancement in process variables during the machining of EN31 steel. Although the effect of the process parameters such as cutting speed, feed rate and depth of cut on responses like surface roughness has been presented by many researchers, still there is a scope of improvement in determining effect of these process variables using an appropriate multi-response optimization technique. Along with the machining parameters, cooling concentration in terms of minimum quantity lubrication (MQL) is also considered. The output responses viz. surface finish achieved during machining and the effect of tool vibration are evaluated. A comprehensive analysis between the input parameters and output responses by using hybrid optimization technique consisting of Taguchi based orthogonal array (TGRA) and grey relational analysis has been accomplished.

Machinability analysis of difficult-to-cut material during ultrasonic vibration-assisted ball end milling

ABSTRACT Vibration-assisted machining has been proven as an excellent material-removal process with its multiple advantages over ordinary machining methods. However, the process is usually applied for the machining of easy-to-cut materials and conventional cutting tools vibrating, at or below the ultrasonic frequency. This study was conducted to evaluate the effect of ultrasonic vibration of the ball end mill with the objective to enhance the machinability of difficult-to-cut material. An analytical model was established to calculate the cutting forces generated during the process. A WC-Co-based ball-nose end mill with a TiAlSiCrN coating was used to perform the machining tests on tool steel (AISI-H13). Machinability was evaluated in terms of cutting forces, chip morphology, rate of wear, and surface integrity. During the machining experiments, cutting forces under the effect of tool vibration were found to be reduced with the improvement in machined surface quality. The obtained results indicate the overall enhancement in the machinability of the work material and hence the technique can be applied to substitute the conventional milling.

Effect of Tool Vibration on Flank Wear and Surface Roughness During High-Speed Machining of 1040 Steel

In recent years, the tool condition monitoring mechanism is necessary for analyzing the failure of the cutting tools in production practices. In a machining environment, steady and catastrophic failures of a tool are general faults associated with a machining process. The relationship between surface roughness, tool wear and vibration is explored during high-speed dry machining by using main input factor. L27 numbers of trials were performed in a CNC lathe with uncoated carbide CNMG120408 tool and alloy steel AISI 1040 workpiece. The predictable model is capable of expecting surface roughness (Ra), tool wear (VBc), and vibration of amplitude using observed data when turning alloy steel. The vibration was recorded only in the turning direction with a uniaxial accelerometer. Additionally, tool flank wear and finished work surface roughness are measured at various combinations of parameters. The outcomes of the work show that the axial feed rate is the main effective turning variable that influences surface roughness largely (91.97%). Optimization of turning process variables plays a significant role in turning to develop quality, manufacturing production rate and decrease production price. In this analysis, an advanced weighted principal component analysis strategy was initiated to optimize process variables in turning of 1040 alloy steel and the optimum relation was found to be d3 (0.5 mm)–f1 (0.06 mm/rev)–v3 (300 m/min). Higher depth of cutting along with largest cutting speed confirms the larger production rate which is desirable for industrial concern. Also, at the optimal setting, the excellent finish of surface with low wear and low acceleration is noticed with an improved S/N ratio of CQL from initial setting. However, the current work presented a better co-relation between tool vibrations, tool wear, and test surface finish which will be beneficial for the industrial uses.

Investigation of the Effect of Tool Vibration on Surface Roughness in the Milling of Ti6Al4V Material

Talaşı imalatta önemli bir alan olan frezeleme işlemleri çok yönlü bir imalat biçimi olup endüstride oldukça yaygın olarak kullanılmaktadır. Frezeleme işleminin istenilen hassasiyetle yapılamaması malzeme üzerinde bazı mekanik sorunlara ve hatta malzeme kayıplarına yol açmaktadır. Ekonomik değeri yüksek olan malzemenin atıl duruma gelmesi zaman, para ve iş gücü kaybına neden olmaktadır. Hata tespit ve tahmini, ürün kalitesini yükseltmek, kullanılan malzeme masraflarını azaltmak ve zamandan tasarruf sağlamak için önemli bir işleve sahiptir. Yapılan bu çalışmada, frezeleme işlemi sırasında, kesici takımda oluşan mekanik titreşimlerin yüzey kalitesi üzerindeki etkileri deneysel olarak incelenmiştir. Yapılan testlerde titanyum (Ti6Al4V) iş parçası kullanılmıştır. Test parametreleri, 4 farklı seviyede kesme hızı (Vc m/dk), 4 farklı seviyede ilerleme oranı (f mm/diş) ve sabit kesme derinliği (ap/mm) alınarak tam faktöriyel yöntemi ile belirlenmiştir. Testlerden elde edilen ortalama yüzey pürüzlülüğü değerleri için regresyon analizleri yapılmıştır. Sonuçlar incelendiğinde, titreşimin ve ilerleme oranının artışı ile ortalama yüzey pürüzlülük değerlerinin arttığı gözlemlenmiştir. Bu durum kesici takımda oluşan titreşimin kesilen iş parçası yüzey pürüzlülüğü üzerinde önemli bir etkisi olduğunu açıkça ortaya koymaktadır. Kesme hızı ve ilerleme oranı miktarlarına göre; yüzey pürüzlülük değeri aralığı 0,33-0,66 µm aralığında değişim göstermiştir. Yüzey pürüzlülük değerlerinin en küçüğü, ilerleme hızının en az olduğu değerlerde görülmüştür. En büyük Ra değeri ilerlemenin en fazla olduğu değerlerde elde edilmiştir. Kesme hızının 50 m/dk, ilerleme hızının 0,10 mm/diş parametreli test yapılırken kesici takımın deforme olduğu görülmüştür. Bu durumun yüzey pürüzlülük değerlerini olumsuz yönde etkilediği düşünülmektedir.

Effects of tool vibration on surface integrity in rotary ultrasonic elliptical end milling of Ti–6Al–4V

Titanium alloys have been applied in aerospace, biomedical, and chemical industries due to their superior mechanical properties. As a novel machining method, rotary ultrasonic elliptical machining has been successfully introduced into high-speed side milling of Ti–6Al–4V recently. However, the surface integrity in end milling of titanium alloy using this method is still unclear. In this study, a comprehensive experiment on surface integrity in rotary ultrasonic elliptical end milling of Ti–6Al–4V was conducted at various vibration amplitudes and cutting speeds. Results show that regular substantial micro-vibration textures in the form of separated ridges are obtained on the machined surfaces in RUEEM. Surface roughness values rise from Ra 0.160 μm to Ra 0.758 μm with the increasing cutting speed and vibration amplitude. Both the thickness of subsurface deformed layer and the value of surface micro-hardness increase with rising amplitude at low cutting speeds, while the hardening effect gradually weakens as the cutting speed increases to 160 m/min. Besides, the values of surface compressive residual stress gradually decrease with vibration amplitudes at low cutting speeds, while opposite trends show at the high cutting speed (160 m/min). This study can provide a new method for the effective control of the surface integrity for high-speed end milling of titanium alloy.

Effects of tool vibration on fiber fracture in rotary ultrasonic machining of C/SiC ceramic matrix composites

Abstract The carbon fibers fracture mechanism depending on fiber orientation significantly affects the machined surface quality of C/SiC composites. The rotary ultrasonic machining (RUM) has been proved to be a beneficial method for C/SiC composites drilling with minor tearing defects at the hole exits. In contrast, the effects of tool vibration on surface topography in RUM of C/SiC composites considering fiber orientation have not been reported. In order for a unique evaluation of surface generating mechanism in RUM of C/SiC composites, several RUM experiments were conducted on 2D-C/SiC composites. The micro structural characteristics of the hole surfaces under various fiber directions, ultrasonic amplitudes and spindle speeds were analyzed. The fiber fracture mechanism in RUM of C/SiC was discovered through theoretical analysis. The results displayed that both fiber cutting direction and cutting speeds significantly affect the surface topography in RUM and CG of C/SiC composites. The tool ultrasonic vibration could contribute to the hole surface quality improvement in RUM of C/SiC composites by the fiber fracture mechanism alteration. With the ultrasonic vibration contribution, the fiber cutting direction tended towards 90° and the cutting speeds were increased. In contrast, due to the non-monotonic effect of the cutting speed on the surface roughness, only when the spindle speeds were relatively low, the higher ultrasonic amplitude apparently contributed to the hole surface quality further improvement.

Effect of tool vibration on chip formation and cutting forces in the machining of fiber-reinforced polymer composites

ABSTRACTThis article investigates the chip formation mechanism and its influence on cutting forces during the elliptic vibration-assisted (EVA) cutting of fiber-reinforced polymer composites. To clarify the effect of the vibration, systematic finite element and experimental studies were performed on both the EVA and the traditional cutting of unidirectional fiber-reinforced polymers with various fiber orientations. The key factors that govern the cutting forces have been taken into account, such as the depth of cut, feed rate, tool vibration frequency and amplitude. The study found that fiber orientation significantly affects the chip formation and cutting forces. Fiber fracture can happen either above or below the trimming path, but that above the path dominates chip formation. When a fiber orientation is less than 90°, chipping is mainly through bending-induced fracture of fibers; when it is beyond 90°, however, chipping is mostly by crushing the fracture of fibers. Compared with a traditional cutting process, the EVA cutting can minimize the fiber orientation effect through localized fiber fracture. A dimensional analysis was then performed to provide a quantitative prediction of the cutting forces.

Discrete element modeling of vibrating tillage tools

Purpose – The analysis of the effect of tool vibrations on the measured and simulated draught forces of cultivator tools. This paper aims to discuss this issue. Design/methodology/approach – Soil bin measurements and discrete element method (DEM)-based simulations. Findings – The soil-tool interaction induced free vibrations of cultivator tools have significant impact on the measured draught force, and the simulations made by using vibrating tools give similar results. Research limitations/implications – Accurate calibration of discrete element model parameters can be done based on the reproduction of the whole Mohr-Coulomb failure line. Draught force ratio – velocity ratio values seem to be independent of tool geometry and soil conditions in case of velocity ratio higher than 2. Practical implications – DEM-based numerical simulations can be used for modeling the effect of tool vibration on the draught force values. During discrete element simulations of soil-tool interaction, the effect of tool vibration may not be neglected. Originality/value – The paper demonstrates that during the discrete element modelling of the soil-tool interaction, the tool vibration phenomenon should not be neglected.

On the tool vibration effects during down-cut peripheral milling process

Improvement in machining efficiency requires better comprehension of multiphysical cutting process phenomenon under real dynamic cutting conditions. Present work suggests a multi-scale interaction of mesoscopic level cutting with macroscopic level machine tool dynamics to optimize cutting process parameters and potentially improve interactive design process. For that, the case of an orthogonal down-cut peripheral milling, for an aeronautic aluminium alloy A2024-T351, has been treated. A finite element based multi-scale dynamic cutting model has been conceived with a commercial finite element based code ABAQUS®/EXPLICIT to predict the chip morphology under dynamic cutting conditions. Later, combines the elasticity of a classical high speed milling spindle system (tool, tool-holder and rotor) with the mesoscopic level chip formation process. A qualitative parametric study with various stiffness and damping coefficient values for high speed milling spindle system shows that, a less rigid un-damped milling system generates higher amplitude tool vibrations during cutting. In this situation, the temperature rises at tool-workpiece interface, enhancing material softening. Present study deals with the consequences of this softening on affecting the chip morphology (evolution of segmented chip morphology), and machined surface integrity. Further, numerical simulation results depict that the higher values of cutting speed and uncut chip thickness are associated with higher values of milling cutter vibration amplitudes.

Ultrasonic Assisted Turning of mild steels

In this work, the advantages and drawbacks of Ultrasonic Assisted Turning (UAT) have been investigated focusing on the effect of tool vibration on surface quality. Several experiments have been performed on mild steels changing the cutting speed, feed and depth of cut, to study how the influence of the ultrasonic vibration on the surface roughness varies depending on the cutting conditions. The results obtained show that the ultrasonic vibration can improve the surface quality. The authors also propose a new booster design based on the theory of longitudinal vibration of a bar with varying cross-sectional area for a higher amplification of the ultrasonic vibration.

Finite-element-based hybrid dynamic cutting model for aluminium alloy milling

The present contribution deals with milling tool vibration effects on chip morphology, cutting force, and cut surface topology. The study concerns an orthogonal down-cut peripheral milling case for aeronautic aluminium alloy A2024-T351. A finite-element-based hybrid dynamic cutting model (HDC model) is proposed to predict the chip morphology under dynamic cutting conditions. The latter is conceived with commercial software ABAQUS®/EXPLICIT and combines the stiffness of a high-speed milling spindle system (tool, toolholder, and rotor) with the chip formation process. A qualitative parametric study with various stiffness and damping coefficient values for a high-speed milling spindle system has been performed. The results concerning chip morphology and cutting force are compared with experimental data, while the surface profiles are compared with those obtained by considering a perfectly rigid spindle system. As expected, a less rigid undamped milling system generates higher-amplitude tool vibrations during milling. In this situation, the temperature rises at the tool—workpiece interface, enhancing material softening. This softening promotes chip segmentation and increases waviness of the machined surface profile. The numerical results show that higher values of cutting speed and uncut chip thickness are associated with higher vibration amplitudes.

Chatter Stability of General Turning Operations With Process Damping

The accurate prediction of chatter stability in general turning operations requires the inclusion of tool geometry and cutting conditions. This paper presents regenerative chip and regenerative chip area/cutting edge contact length based dynamic cutting force models, which consider cutting conditions and turning tool geometry. The cutting process is modeled as it takes place along the equivalent chord length between the two end points of the cutting edge. The regenerative chip model is simple, and the stability can be solved directly. However, the three-dimensional model considers the effect of tool vibrations at the present and previous spindle revolutions on the chip area, chord length, and force directions and is solved using Nyquist stability criterion. The penetration of worn tool flank into the finish surface is considered as a source of process damping. The effects of the nose radius, approach angle of the tool, and feedrate are investigated. The proposed stability model is compared favorably against the experimental results.

Model for surface topography prediction in peripheral milling considering tool vibration

This paper presents a model for the prediction of surface topography in peripheral milling operations taking into account that the tool vibrates during the cutting process. The model includes the effect of tool vibrations in the equations of the cutting edge paths, which are transformed into equivalent polynomial equations and solved for discrete positions along the feed direction by applying a standard root finder. Through this procedure, surface topography generation is simplified with respect to other models in literature. The model allows the topography, the roughness values and the form errors of the milled surface to be predicted. Cutting test results show good agreement with model predictions.

The effect of tool vibrations on the flank surface created by peripheral milling

Tool vibrations have a significant influence on the surface quality with respect to surface location error and roughness. Even chatter-free milling processes can produce a high surface location error since chatter-free does not necessarily mean vibration-free. This article describes a geometric model for predicting the surface formation resulting from peripheral milling processes when tool vibrations are present. This model enables one to predict and minimize the roughness and location error of the flank surface. Comparisons between simulations and experiments show the effectiveness of this modeling approach. An important result of this research is that it has shown that milling at a stability maximum does not generally yield the best surface quality.

Ultraprecision Ductile-Regime Cutting of Brittle Materials

Soda-lime glass is a typical brittle material, which is difficult to realize ductile-regime machining by using conventional cutting technology due to the extremely small critical depth of cut. In this work, the micro-deformation characteristics of this kind of materials were analyzed by micro indentation. Ultrasonic vibration assisted diamond cutting was performed in order to investigate the effect of tool vibration on material removal process and surface quality. The profiles of cut surfaces were measured and compared with those obtained by conventional diamond cutting. Real depths of cut in ultrasonic vibration cutting correspond well with the nominal ones. The change in the tribology of the cutting process as well as the alteration of the deformation mechanism of the work material might be responsible for the reduction in tool wear in vibration cutting.

Ultraprecision Cutting of Glass BK7

The development of the capability to machine glass materials to optical quality is highly desirable. In this work, the deformation characteristics of brittle materials were analyzed by micro and nano indentations. Diamond cutting of optical glass BK7 was performed in order to investigate the tool wear mechanism in machining of brittle materials and the effect of tool vibration on material removal mechanism. The tool wear mechanism was discussed on the basis of the observation of wear zone. Ductile-mode cutting has easily been achieved with the application of ultrasonic vibration during cutting of glass. It was confirmed experimentally that the tool wear and surface finish were improved significantly by applying ultrasonic vibration to the cutting tool.

Microscopic topographical analysis of tool vibration effects on diamond turned optical surfaces

In diamond turning for the manufacture of optical surfaces, a certain degree of relative vibration is inevitably encountered between the tool and work, deteriorating the surface quality. In this paper we first describe how the tool vibration affects the surface profiles in microscopic level, and then propose a metrological scheme to identify any existence of tool vibration with a minimum effort of surface measurement and analysis.