Comparative Analysis of Chatter Vibration Frequency in CNC Turning of AISI 4340 Alloy Steel with Different Boundary Conditions

Journal of Covenant Engineering Technology (CJET) Vol. 1, No. 1, March 2018

An Open Access Journal Available Online

Okonkwo Ugochukwu C.1, Nwoke Obinna N.2, Okokpujie Imhade P.3

1Department of Mechanical Engineering, Nnamdi Azikiwe University, P.M.B. 5025, Awka, Nigeria 2Department of Mechanical Engineering Technology, Akanu Ibiam Federal Polytechnic, Unwana, Ebonyi State. 3Department of Mechanical Engineering, Covenant University, P.M.B 1023, Ota, Ogun State, Nigeria Corresponding Author, [email protected]

Abstract- In this study, an experimental investigation of chatter vibration frequency in CNC turning of AISI 4340 Alloy Steel material was carried out, with uncoated carbide tool insert (TPG 322) on Fanuc 0i TC CNC lathe machine, with two boundary conditions. The experimental design adopted for this study is the Taguchi parameter design with L9 orthogonal array. Turning tests were carried out on nine samples of the test-piece material for the clamped-free (C-F) condition, and the tests replicated on another set of nine test-pieces for Clamped-Pinned, so- called C-SS workpiece boundary condition. Chatter vibration frequencies were measured using MXC-1600 digital frequency counter and the frequency plots continuously analysed through DTO 32105 sound signal and frequency analyzer. The main objective is to investigate the process parameters’ performances on the work-piece material of AISI 4340 alloy steel, and to carry out comparisons between the two different boundary conditions vis-à-vis the effects of process parameters which are cutting speed, feed rate and depth of cut on the chatter vibration frequency for the orthogonal turning operation. Chatter vibration frequency values for the C-SS scenario were found to be up to 30% lesser when compared to the C-F machining scenario. Introduction of the tailstock used in pinning the free-end of the slender work-pieces reduced the chances that workpiece would bend; whereas absence of the pinned end means that workpiece may be skewed at an angle in the chuck with increased dynamic deflections at the free end leading to

Okonkwo Ugochukwu C., et al CJET Vol.1 No.1, March. 2018 (Special Edition) 13-30

more aggressive workpiece and cutting tool perturbations which are known to favour cutting instability.

Keywords: CNC lathes machine, Chatter Vibration, Cutting Stability, Machining Parameters and Taguchi Method.

I. Introduction

Regenerative vibrations are the self- maximum cutting parameters, when excited vibrations which occur the limits should instead be defined during certain machining processes by the strength of the tool and the as a result of the interactions between power of the machine. It is never a the workpiece –machine tool good idea to keep machine in the structures and the cutting process face of strong chatter as chatter is dynamics. They are also referred to very bad for tool and machine life, as chatter vibration. Chatter is the and interferes with the accuracy of most obscure and delicate of all the the machining operation. Chatter can problems facing a machinist. feed on itself, much like the feedback It is a resonant phenomenon where on a loudspeaker “Public Address” the machine or work-piece vibrates. system that creates those terrible It can become quite violent and screeching noises. For that reason, it generate a distinctive loud noise. is sometimes called "regenerative Every system of spindle, tool holder chatter." The regenerative and tool has some set of frequencies phenomenon is key to understanding at which it naturally wants to vibrate. how chatter works. A vibration in the At certain higher spindle speeds, it tool leads to a wave in the work- becomes possible for cutting edges to piece; constant vibration creates a strike the part frequently enough that steady series of these waves. The the impacts cleanly synchronize with dynamic characteristics of the entire one of these natural frequencies. The machining system in terms of the smooth cutting that result, makes it natural frequencies, the damping possible to cut deeper without properties, flexural rigidity, and the straining the tool or the machine. stiffness of the machine tool Chatter is broadly classified in two structures, also affect the vibration categories: Primary chatter and magnitude. secondary chatter. Primary chatter is Chatter diminution remains obvious sub classified as frictional chatter, panacea for machining stability. thermo-mechanical chatter and Chatter avoidance techniques aim to mode-coupling chatter. Primary prevent chatter from occurring chatter is because of the friction during the machining process, by between tool and work piece and it selecting spindle speed and depth of diminish with the increase in spindle cut based on a stabilit chart the so- speed, while secondary chatter is a called stabilit lobe diagram as corollary of the regeneration of shown in igure 1. This was first waviness of the surface of the work introduced by Tobias and Fishwick piece [1]. [2]. If the process parameters are In numerous machining processes, above the stability borderline, chatter chatter is the barrier that defines the will occur, however, if the process

14 Okonkwo Ugochukwu C., et al CJET Vol.1 No.1, March. 2018 (Special Edition) 13-30 parameters are below the stability depth-of-cut below which stable borderline, chatter will not occur. machining is guaranteed regardless The critical stability borderline is the of the spindle speed.

Figure 1: Stability Lobe diagram

The lobed behaviour of the stability forced vibrations are extremely borderline allows stable lobe-regions small, the slightest marks left on the to form; thus, at specific ranges of cutting surface cause’s vibrations in spindle speeds, the depth-of-cut may the chip thickness for the following be substantially increased beyond the tooth or cut. This regenerative effect critical stability limit. These lobe- is the most important cause of regions become smaller as the chatter. For this reason it has become spindle speed decreases. However, a convention that “chatter” onl stability is increased at low spindle refers to regenerative chatter. It is speeds due to the process damping possible to distinguish between phenomenon [3]. In general, frictional chatter, mode coupling diminution of chatter technically chatter and regenerative chatter refers to a method to improve the based on the mechanism that causes stability margin in the cutting the vibration. Frictional chatter process. Various methods for chatter occurs when rubbing on the control have been proposed such as clearance face excites vibration in spindle speed manipulation or the direction of the tangential force variation and use of vibration and limits in the radial force absorbers. Vibration absorption direction. Mode coupling chatter method refers to adding an additional exists as the vibration in the radial mass to the structure to passively direction generates vibration in the absorb the unwanted vibration tangential direction and vice versa. energy [4-6]; whereas active control This results in simultaneous vibration requires external power to counteract in the tangential and radial force the unwanted vibration [7-10]. It is directions. This can be caused by a well documented that the number of sources such as friction on fundamental cause of chatter under the rake and clearance surfaces, chip most machining conditions is the thickness variation, shear angle regeneration effect [11]. Even when

Okonkwo Ugochukwu C., et al CJET Vol.1 No.1, March. 2018 (Special Edition) 13-30 oscillations and the regeneration in the cut, it encounters this wavy effect [12]. surface and generates a new wavy Regenerative chatter often occurs surface. The chip thickness and, because most cutting operations hence, the forces on the cutting tool involve overlapping cuts which can vary due to the phase difference be a source of vibration between the wave left by the amplification. Considering the previous tooth and the wave left by machining operation in igure 2, the the current one. This phenomenon combination of the waviness on the can greatly amplify vibrations, and surface left by the previous tooth and therefore instability. For the case of vibration of the currently cutting turning of slender workpieces, this tooth creates the periodically phenomenon is more common and changing chip thickness. In other pronounced especially when words, tool vibrations leave a wavy adequate nodal supports are not surface and when the cutting tooth is available.

Figure 2: Schematic diagram showing a typical metal cutting action

Machining parameters such as machining is strongly related to the cutting speed, feed rate, and depth of material removal rate. The material cut do affect the product quality and removal rate for a turning operation production costs. Thus, it is is given by the product of cutting important to use optimization parameters (cutting speed (Vc), feed technique to determine optimal levels rate (f), and depth of cut (d)). of these parameters so as to reduce Therefore, if an increase in the production costs and to achieve productivity is desired then an the desired product quality increase in these three cutting simultaneously [13]. One of the main parameters is required. But, there are objectives in the optimization of a limits to these cutting parameters turning process is minimization of since they also have an effect on the the cost of production and tool life, tool wear, cutting forces, maximization of the production rate cutting temperature and surface while keeping the quality of quality [15-22], when this process is machined parts as per design not well defined during machining speciﬁcations [14]. The cost of operation it can lead to fatigue, creep

Okonkwo Ugochukwu C., et al CJET Vol.1 No.1, March. 2018 (Special Edition) 13-30 and can increase the rate of to improve the quality of machining corrosions in our manufacturing operation with different boundary product [23,24]. conditions

Nwoke et al [23] carried out II. Materials and Methods experimental investigation of chatter The work piece material used for the in CNC turning for 4340 Alloy Steel study are round bars of AISI 4340 material and developed a regression alloy steel of length 381 mm and models for chatter frequency diameter 38.1 mm. Parameters values prediction, and the model predicted used for the turning experiments could up to 99.5% accuracy for the were typical of the turning machine material. Ezugwu et al [1] study used, while considerations were paid stability analysis of model with regards to the strength of the regenerative chatter of milling cutting tool. For both the clamped- process using first order least square free (C-F) and clamped-simply full discretization method and supported(C-SS) end conditions, developed a detail computational experiments were performed using algorithm for the purpose of the Goodway CNC lathe with Fanuc delineating stability lobe diagram controller. Signal acquisition and into stable and unstable regions using processing were done with the aid of mathematical models. These an accelerometer, microphone, algorithms enabled the performance digital frequency counter, and a of sensitivity analysis. frequency calibrated oscilloscope. Therefore keeping this in view, many Experimental investigation was done researches are still on-going with at the Mechatronics Workshop of various objectives most of which Akanu Ibiam Federal Polytechnic, borders on how to evaluate and Unwana, Ebonyi State, Nigeria. suppress chatter for specific Detailed information on chemical machining operations; and how to composition and the physical minimize production limitations properties of the AISI 4340 alloy imposed by chatter. This research steel is provided in tables1and 2, focus on the chatter vibration and it while details of the experimental effect to machining operation and to outlay for the turning tests is shown developed mathematical model that in table 3. can predict chatter vibration, in other

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Table 1: Chemical Composition of 4340 Alloy Steel

Element C Cr Fe Mn Mo Ni P Si S

Content 0.38- 0.7- Balance 0.6- 0.2- 1.65- 0.035max 0.15- 0.04max % 0.43 0.9 0.8 0.3 2 0.3

Table 2: Physical Properties and mechanical properties of 4340 Alloy Steel Properties Units Density 7850 Kg/m3 Melting point 1427°C Tensile strength 745 MPa Yield strength 470 MPa Bulk modulus 140 GPa Shear modulus 80 GPa Elastic modulus 190-210GPa

Table 3: Details of the Experimental Outlay for both boundary conditions EXP. MATERIAL CUTTING INPUT RESPONSE

1RUNS to 9 4340 Alloy TPGTOOL 322 CuttingPARAMETERS speed ChatterPARAMETERS Frequency (ωc) Steel Feed rate in Hz Depth of cut

Experiments were performed by experimentally using the cutting AISI 4340 material using accelerometer and the data uncoated carbide inserts (TPG 322) acquisition system. The results of the on Fanuc 0i TC CNC lathe. The experiment were measured using boundary condition of the work piece DTO 32105 frequency analyzer and at chuck end is clamped while the MXC-1600 digital frequency other end of the work piece is free counter. The experimental setup is for the first case study; and Clamped shown in Figure 3 and the schematic – Simply Supported for the second arrangement is portrayed in figures 4 scenario. Natural frequency of the and 5 for the referenced scenarios. work piece was determined

Figure 3: Experimental setup

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Design of the experiment for the the greatest effect. To select an current research is based on the appropriate orthogonal array for Taguchi method. Taguchi Parameter conducting the experiments, the Design as a type of factorial design is degrees of freedom are to be similar to traditional DOE methods computed. The same is given below: in that multiple input parameters can (퐷OF)푅 = 푃∗(퐿−1) (3) be considered for a given response. The most suitable orthogonal array The Taguchi method allows us to for experimentation is L9 array as predict our ideal combination of shown in Table 4 [17]. Therefore, a independent variables (or input total number of nine experiments variables) to give the best result on a were done for each scenario of the dependent variable. It can also be workpiece conditions. used to find which input variable has

Table 4: Orthogonal Array (OA) L9 Experiment Control Factors No 1 2 3 1 1 1 1 2 1 2 2 3 1 3 3 4 2 1 3 5 2 2 1 6 2 3 2 7 3 1 2 8 3 2 3 9 3 3 1

The L9 orthogonal array with all combination is tested for three values selected for the experimental replications for effective error run is shown in Table 4. There are 9 reduction and for accurate S/N ratio parameter combinations that need to with reasonably low and stable be tested. Each parameter chatter frequency. The experimental

Okonkwo Ugochukwu C., et al CJET Vol.1 No.1, March. 2018 (Special Edition) 13-30 plan was developed to assess the (Factors) as given in Table 5. The influence of cutting speed (v), feed factors levels were chosen within the rate (f), and depth of cut (d) on the intervals recommended by cutting Chatter Frequency (ωc) for the tool manufacturer. Three referenced workpiece end conditions cutting variables at three levels led to so that variations in the response a total of 9 tests for 4340 alloy steel function could be used to assess the turning operation, for each of the effect of pinning the free-end of the scenarios, according to the Taguchi workpiece. Three levels were L9 orthogonal array design allocated for each Parameter

Table 5: Factor levels used in the experimental design Parameters Levels (Factors) 1 2 3 Cutting speed, v (m/min) 140 230 320 Feed, f (mm/rev) 0.05 0.10 0.15 Depth of cut, d (mm) 0.10 0.30 0.50

III. Results and Discussion vibration frequency values are captured Result of the turning tests are captured in in column 7. table 6. Percentage reductions in chatter

Table 6: Experimental results for chatter vibration frequency for (C-F) and (C-SS) condition. Experiment Speed Feed rate Depth (C-F) (C-SS) % Reduction No (m/min) (mm/rev) of Chatter Chatter in Chatter Cut Frequency Frequency Frequency (mm) (ωc) ln (ωn) ln Hz (ωn) ln Hz Hz 1 140 0.05 0.1 150.25 115.20 23.32 2 140 0.10 0.3 366.21 260.50 28.86 3 140 0.15 0.5 610.94 467.70 23.44 4 230 0.05 0.3 135.33 100.90 25.44 5 230 0.10 0.5 355.56 248.73 30.04 6 230 0.15 0.1 532.44 400.20 24.83 7 320 0.05 0.5 130.00 99.30 23.61 8 320 0.10 0.1 228.04 165.90 27.24 9 320 0.15 0.3 463.54 324.45 30.00

Numerical analysis of the results coefficient of simple determination, carried out, using SPSS 22.0, reveals r2 99% (averagely) means that the that there is a very strong correlation explanatory variables (v, f, and d) between the dependent variable explain changes in chatter vibration (chatter vibration frequency) and the frequency as high as 99 per cent for independent variables (cutting speed, the referenced scenarios. Regression federate, and depth of cut). The coefficients computed indicates that

Okonkwo Ugochukwu C., et al CJET Vol.1 No.1, March. 2018 (Special Edition) 13-30 increase in federate and/or depth of was obtained by plotting chatter cut would bring about positive vibration frequency values against increase in chatter vibration the various process parameters frequency; while increase in cutting (depth of cut, cutting speed and feed speed would mitigate chatter. The rate). Chatter vibration frequency computed values of the regression values were simultaneously plotted coefficients revealed that there were against two process parameters while no cross-product interaction effects. keeping the other one constant. Response Table developed (– based Figures 5–10 show the experimental on S/N ratio concept) indicates that results obtained from the effect of the optimal cutting condition for the process parameters on chatter referenced workpiece boundary vibration frequency. conditions occurred when v=320 Effects of cutting speed and feed m/min, f=0.05mm/rev, and rate on chatter vibration frequency d=0.5mm. In addition, it was found Figure 5 and 6 show the Contour that feed rate was the most plots of chatter vibration frequency influencing factor contributing vs. cutting speed and feed rate in (C- 89.84% to chatter frequency, cutting F) and (C-SS) conditions, 21 speed 5.79% and depth of cut 3.92% respectively. It can be seen from respectively, averagely, for the test these figures that there is indeed an material used. interaction which has a linear Dispositions of chatter vibration relationship on the chatter vibration frequency were seen to depend frequenc . Speciﬁcall at cutting substantively on the combined values speed of 140 m/min and feed rate of of the machining parameters. 0.05 mm/rev, the chatter vibration However, on a general note, pinning frequency obtained during C-F the free-end of a slender workpiece condition was 150.25Hz while that was found to favour reduced for the C-SS condition was 115.2Hz. machining vibrations leading to The highest chatter vibration improvements in stability margins. frequency of the C-F condition Contour plots were developed with revolves around 610.94Hz while that MINITAB 16; the numerical of the C-SS condition revolves analyses thereto are detailed in the around 467.7Hz as shown in Figures following subsections. 5 and 6, respectively. Chatter Effects of process parameters on vibration frequency as low as 130Hz chatter vibration frequency in and 99.3Hz can be obtained from C- clamped-free(C-F) and clamped- F and C-SS condition and this region simply supported(C-SS) turning is at the top-left side of the two conditions Figures. On a general note, The effects of process parameters on increasing the cutting speed reduces chatter vibration frequency in turning the chatter vibration frequency. of AISI 4340 alloy steel with Apparently, increasing the cutting different boundary conditions were speed increases the cutting force and investigated using contour plots of eliminates the built-up edge (BUE) the results obtained in C-F and C-SS tendency. At low cutting speed conditions. The graphical evaluation (m/min), the unstable larger BUE is

Okonkwo Ugochukwu C., et al CJET Vol.1 No.1, March. 2018 (Special Edition) 13-30 formed and also the chips fracture increased; chips become readily producing the vibration discontinuous and were deposited frequency. As the spindle speed between work piece and tool leading (m/min) increases, the BUE to increased coefficients of friction vanishes, chip fracture decreases, and and more interruption resulting in hence, the vibration frequency poor surface finish and productivit . decreases. These findings were in In C-SS condition, the other end is line with observations made by pinned using a tailstock. Due to the Ezugwu et al [1], Minis and additional support from the tail stock, Yanushevsky [18] in related studies. the flexural rigidity of the workpiece In this investigation it was also was improved upon; tendencies for observed that an increase in feed rate lateral deflections were reduced significantl increases the chatter leading to reductions in possible vibration frequency. Increasing feed vibration amplitudes. Consequently, rate increases vibration and heat the chatter vibration frequency generated, which causes an increase values were reduced when compared in chatter vibration frequency. with C-F condition. This result is in This result is also in line with the agreement with the result obtained result made by Nwoke et al [19], by Zhang, and Sims [10]. which says as the feed rates were

(C-F) Chatter 300 Frequency (ωc) < 200

275 200 – 300

) n

i 300 – 400

m 400 – 500

/ 250 500 – 600

m (

> 600

d e

e 225

n i

t 200

u c

175

150

0.050 0.075 0.100 0.125 0.150 feed rate(mm/rev)

Figure 5: Contour plot of chatter vibration frequency vs. cutting speed and feed rate in (C-F) condition.

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C-SS chatter 300 frequency < 100 100 – 200

275 200 – 300 )

n 300 – 400 i

m > 400

/ 250

(

e e

p 225

i t

t 200

u c

175

150

0.050 0.075 0.100 0.125 0.150 feed rate(m/rev)

Figure 6: Contour plot of chatter vibration frequency vs. cutting speed and feed rate in (C-SS) condition.

Effects of the depth of cut and feed rate on chatter vibration frequency Figures 7 and 8 shows the contour vibration frequency and this can also plots of chatter vibration frequency lead to poor surface finish and vs. radial depth of cut and feed rate plausible reduction of the tool life or in (C-F) and (C-SS) conditions, outright damage to the tool, respectively. At instance, the cutting depending on the severity of the speed is kept constant. Studying the interaction between feed and depth contour lines, one can clearly notice of cut. It is also in line with the that the feed rate has more significant works done by Ema and Marui [4], effect than the axial depth of cut. At Okokpujie and Okonkwo [16] where low feed rates, the chatter vibration their result shows that surface frequency is very small roughness values increases as the notwithstanding the variation of the feed rate is increased. The above depth of cut. However, as the feed scenario is found to be true for both rate increases, it increases the chatter C-SS and C-F conditions.

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0.5 (C-F) Chatter Frequency (ωc) < 200 0.4 200 – 300

) 300 – 400

m 400 – 500

m 500 – 600 (

t > 600

u c

0.3

e d 0.2

0.1 0.050 0.075 0.100 0.125 0.150 feed rate(mm/rev) Figure 7: Contour plot of chatter vibration frequency vs. radial depth of cut and feed rate in (C-F) condition.

0.5 C-SS chatter frequency < 100 100 – 200 0.4 200 – 300

) 300 – 400

m > 400

(

u c

0.3

e d 0.2

0.1 0.050 0.075 0.100 0.125 0.150 feed rate(m/rev) Figure 8: Contour plot of chatter vibration frequency vs. radial depth of cut and feed rate in (C-SS) condition.

Effects of cutting speed and depth of cut on chatter vibration frequency studied. At higher cutting speed, the Figures 9 and 10 shows the Contour chatter vibration frequency was plots of chatter vibration frequency greatly reduced even when the depth vs. radial depth of cut and cutting of cut was increased. On the other speed in (C-F) condition and (C-SS) hand, it was observed that the chatter conditions, respectively. At instance, vibration frequency witnessed under the feed rate is kept constant. It can C-F condition was far more, be clearly seen that the spindle speed especially using low cutting speed has more impact when compared compared with that of the C-SS with the depth of cut when the colour condition. Speciﬁcally, at spindle variation and contour lines are speed of 320 m/min and feed rate of

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0.05 mm/rev, the chatter vibration condition was 130Hz while that for frequency obtained during C-F the C-SS condition was 99.3Hz.

0.5 (C-F) Chatter Frequency (ωc) < 200 0.4 200 – 300

) 300 – 400

m 400 – 500

m 500 – 600 (

t > 600

u c

0.3

e d 0.2

0.1 150 175 200 225 250 275 300 cutting speed (m/min)

Figure 9: Contour plot of chatter vibration frequency vs. radial depth of cut and cutting speed in (C-F) condition.

0.5 C-SS chatter frequency < 100 100 – 200 0.4 200 – 300

) 300 – 400

m > 400

(

u c

0.3

e d 0.2

0.1 150 175 200 225 250 275 300 cutting speed(m/min)

Figure 10: Contour plot of chatter vibration frequency vs. radial depth of cut and cutting speed in (C-SS) condition.

Comparisons between chatter the turning of AISI 4340 alloy steel vibration frequencies (ωn) for under clamped-free (C-F) turning clamped-free (C-F) and clamped- condition (column 5), clamped- simply supported (C-SS) boundary simply supported (C-SS) turning condition. condition (column 6) and percentage

Table 6 shows the results of the reduction in chatter vibration experiments for the various cutting frequency (column 7). A total of 18 parameters and measured chatter experiments were carried out: 9 for clamped-free (C-F) condition and 9 vibration frequency (ωn) values for for clamped-simply supported (C-

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SS) condition. The concept of application of C-SS turning condition clamped-simply supported C-SS) is a greatly improves the chatter vibration precise solution in achieving reduced frequency when compared with C-F chatter vibration frequency, tool turning condition, all other wear and to achieve better surface advantages notwithstanding. It can finish as well as long tool life while be seen that a reduction of up to 30% maintaining cutting force and power chatter vibration frequency value can at reasonable level. C-SS not only be obtained in the turning of AISI reduces chatter vibration frequency, 4340 alloy steel processes by the tool wear and surface finish but application of C-SS. These findings tends to cause decay in term of noise are in line with observations made by pollutions often associated with the Zhang and Sims [10] in a related C-F scenarios. From the comparison study. The comparison between C-F between the chatter vibration and C-SS turning condition is shown frequency (ωn) for clamped-free (C- in Figure 11. Besides, there is more F) and clamped-simply supported (C- efficient penetration of cutting tool SS) boundary condition carried out into the cutting region due to the in Table 6, it would be seen that increased firmness achieved through there is significant improvement in the pinned end. The implication is the chatter vibration frequency of that turning operations under pinned about a maximum of 30% which is end condition may proceed with shown in the reduction in the average more aggressive feeds and depth of chatter vibration frequency values of cuts as the pinned end provides the test data. The results in Table 6 resistance to lateral deformation and which were clearly depicted in dampens the self exciting tendencies Figure 11 for chatter vibration usually associated with regenerative frequency generally show that chatter.

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Figure 11: Comparisons between chatter vibration frequency (ωn) for clamped-free (C-F) and clamped-simply supported (C-SS) turning condition.

IV. Conclusions optimized cutting condition during Experimental works have been turning process occurred at cutting carried out on turning of AISI 4340 speed of 320 m/min, feed rate of alloy steel with different boundary 0.05 mm/rev and depth of cut 0.5 conditions, namely: the C-F and C- mm. For this condition, the SS workpiece end fixings. A minimum chatter vibration comparison of the effects of process frequency was 130Hz for C-F and parameters in C-F and C-SS 99.3Hz for C-SS environments. conditions on the chatter vibration  In the order of influence to chatter frequency was made. Chatter vibration frequency, feed rate was vibration frequency values for C-SS found to be the most influencing condition were lower with up to 30% factor contributing 89.84% to reduction when compared to C-F chatter frequency, cutting speed conditions. C-SS turning condition 5.79% and depth of cut 3.92% was found to be a better and more respectively, averagely, for the test reliable condition, whenever material used. applicable, because it reduces  Application of the chuck used in machining noise, chatter vibration pinning the free-end led to frequency and the numerous improved workpiece stability, direct/indirect negative consequences reduced workpiece and cutting tool thereto and offers ample opportunity perturbations and vibration for an improved productivity. The amplitudes. Furthermore, important conclusions drawn from machining noise and chatter the research are summarized as vibration frequency were seen to follows: drop appreciably which means that  Analysis of the experimental values higher MRR can be achieved. of Table 5 revealed that the

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