RESEARCH PAPER CONDITION MONITORING OF SIGLE POINT CUTTING TOOL FOR LATHE MACHINE USING FFT ANALYZER

Transcription

1 RESEARCH PAPER CONDITION MONITORING OF SIGLE POINT CUTTING TOOL FOR LATHE MACHINE USING FFT ANALYZER Snehatai S. Khandait 1 and Prof.Dr.A.V.Vanalkar 2 1 P.G.Student,Department of mechanical KDK College of Engineering Nagpur 2 Professor,Department of mechanical KDK College of Engineering Nagpur Abstract- In lathe machine during machining operation, the quality of surface finish is an important requirement for many turned work- pieces. Thus the choice of optimized cutting parameters is very important for controlling the required surface quality. The main aim of this concept is to maintain the quality of the product. In this concept mainly focused on the misalignment of shaft, looseness in machine element. The focus of present experimental study is to optimize the cutting parameters using two performance measures, machine tool vibration and work-piece surface roughness The prediction and control of vibration between the tool and work piece is important as guideline to the machine tools user for an optimal selection of depth of cut, cutting speed, tool feed rate to minimize the vibration. Mainly it focused on turning operation of lathe and problems occurs during this process while machining operation. In machining operation there are different variables deleterious desired results. In this process the behavior of machine tool, cutting tool life and cutting tool vibration are the complex phenomenon which influences on the dimensional precision of the components to be machined, the cutting tool vibrations are mainly influenced by cutting parameters like cutting speed, depth of cut and tool feed rate. This entire fault will be studied by using FFT analyzer. In this project work, lathe machine cutting tool are worked at particular speed.to check the accuracy of experiments, The influences of the different cutting parameter on the vibration of cutting tool. I. INTRODUCTION Machine and machine tool are always subjected to vibration during machining operation. These vibrations are mainly causes due to In- homogeneity s in the work piece material Variation of chip cross section Disturbances in the work piece as well as different cutting speeds or tool drives Dynamic loads generated by acceleration/deceleration of massive moving components Vibration transmitted from the environment Self-excited vibration generated by the cutting process. The tolerable level of relative vibration between tool and work piece, is determined by the required surface finish and machining accuracy as well as by detrimental effects of the vibration on tool life. Machine tools operate in different configurations like positions of heavy parts, weights, dimensions, and positions of work pieces and at different regimes i.e, spindle rpm, number of cutting edges, cutting angles, etc. different vibratory modes can be prominent depending on the circumstances. The looseness, misalignment, Imbalancing during machining operation. To assess the influence of various structural components on the overall operation breakdown of deformation (or compliance) at the cutting edge must be constructed analytically or experimentally on the machine. The most important aim of any maintenance program is the elimination of machine Breakdowns. Causes of vibration in lathe machine 1.1Vibration due to Unbalancing: Unbalancing is defined as an unequal distribution of mass causing mass axis to differ from bearing axis. During rotation the unequal mass along with the radial acceleration due to rotation create a centrifugal force. This results on vibration of the bearing. Balancing is procedure in which the mass DOI: /IJMTER FFGOT 146

2 International Journal of Modern Trends in Engineering and Research (IJMTER) Volume 4, Issue 1, [October 217] ISSN (Online): ; ISSN (Print): distribution of mass on chucks of lathe machine. In some cases balancing may result in partial or temporary reduction of vibration, which produces force 1x at rpm,has been found one of the most common causes of lathe vibration. 1.2Vibration due to misalignment: Vibration due to misalignment means when shaft are out of line. Parallel misalignment occurs when the shfts of two rotor are parallel but not exactly aligned.generally misalignment occur during assembly of machine as well as it can occur during maintence of machine. Vibration due misalignment can be radial or axial it depends on the shaft of on which rotar works. 1.3Vibration due to looseness: Vibration due to looseness occurs by improper arrangements of machine components like, work pieces not tightly fixed, tools not properly fixed. Mainly looseness in machine causes the vibration while machining operation. Operation due to looseness of machine can effect on the working as well as chances of damaging the machine. II. WORK METHODOLOGY After noticing questionable frequencies technicians must look for machine problems. Some primary sources of excessive vibration are imbalance, misalignment, and mechanical looseness. Experienced personnel may discover faulty equipment by looking, feeling, or even smelling. Finding less obvious problems, however, requires understanding how various components vibrate. Imbalance, for example, it can produce vibrations with high amplitude at frequency equal to shaft speed. Initial bearing defects, on the other hand, generate low amplitudes and high frequencies. Gear-mesh vibrations also have low amplitudes with frequencies depending on shaft speed and the number of gear teeth Vibration from pure imbalance is a once-per-revolution sinusoidal waveform. On an FFT spectrum, this appears as a high 1X amplitude without harmonics. Although other faults can produce high 1X amplitudes, they usually produce harmonics as well. Misalignment is either angular or parallel and often a combination of the two. Angular misalignment causes axial vibration at running-speed frequency. Parallel misalignment produces radial vibration at twice or three times running-speed frequency. 1X and 2X readings often appear simultaneously because of combined angular and parallel misalignment. Few faults other than misalignment produce excessive 3X vibration. Possible misalignment causes include thermal expansion after aligning cold machines, coupling properly aligned machines to misaligned ones, and uneven, settling foundations. Imbalance and misalignment can cause bearings to carry higher dynamic loads than their design specifications. Mechanical looseness also leads to bearing failure. It generally appears on an FFT spectrum as a long string of rotating-frequency harmonics or 1 2 rotating-frequency harmonics. Machines with loose mountings or loose internal components are two types of mechanical looseness. If looseness results from a component, such as a fan blade, the part could detach and cause secondary damage. Indirect sources, such as looseness and imbalance, are not the only causes of bearing failure. Problems come All rights Reserved 147

3 International Journal of Modern Trends in Engineering and Research (IJMTER) Volume 4, Issue 1, [October 217] ISSN (Online): ; ISSN (Print): excessive loads, improper lubrication, handling, and installation. Initial bearing fatigue produces shear stresses that appear immediately below the load-carrying surface. These stresses eventually cause cracks that gradually propagate to the surface. Excessive loads or improper lubrication may also produce surface cracks that grow into the material. Procedure During the experimentation FFT analyzer connected to lathe machine. Machining operation takes place by turning process using single point cutting tool on various parts of lathe machine for taking graphs on various loading condition. Graphs takes on various parts of lathe by applying loading condition by keeping motor speed at 48 RPM. For determining the maximum vibration on lathe machine various graphs taken on various parts of lathe machine. The parts are considerd to be lathe foundation,lathe bed,lathe cross slide, lathe tool post, lathe chuck using single point cutting tool with loading condition. But while taking the graphs using fft analyzer it shows maximum vibration at lathe chuck which contain bearing. Graphs of various parts of lathe machine showing All rights Reserved 148

4 International Journal of Modern Trends in Engineering and Research (IJMTER) Volume 4, Issue 1, [October 217] ISSN (Online): ; ISSN (Print): Obeservation table drawn from graphs Name m/ Lathe foundation Lathe Bed Cross slide Tool post Chuck All rights Reserved 149

5 frequency frequency frequency International Journal of Modern Trends in Engineering and Research (IJMTER) Volume 4, Issue 1, [October 217] ISSN (Online): ; ISSN (Print): III. AMPLITUDE GRAPHS Lathe Foundation Lathe bed Lathe Cross slide All rights Reserved 15

6 frequency frequency International Journal of Modern Trends in Engineering and Research (IJMTER) Volume 4, Issue 1, [October 217] ISSN (Online): ; ISSN (Print): Lathe Tool post Lathe Chuck IV. RESULT AND CONCLUSION From the above graphs it is shows that the while performing turning operation and taking the graphs on various parts of lathe machine it observes that maximum vibration performs at lathe chuck. vibrations occurs at various parts i.e, lathe bed,foundation,cross slide, tool post and chuck but studying all the graphs and observation table it is conclude that maximum stress occurs at lathe chuck containing bearing. REFERENCES [1] Kegg RL (1984) On-line machine and process diagnostics. Ann CIRP 32(2): [2] Bertele OV (199) Why condition monitor? In: Condition Monitoring, Proceedings of the 3rd International Conference, Windsor, UK, October, pp 3-12 [3] Neale MJ (1985) The benefit of condition monitoring. In: Condition monitoring of machinery and plant, Mechanical engineering publica- tions Ltd., The Institution of Engineers, London, pp 25-3 [4] Martin KF (1994) A review by discussion of condition monitoring and fault diagnosis in machine tools. Int J Mach Tools Manuf 34(4): [5] Saravanan S, Yadava GS, Rao PV (23) Machine tool failure data an- alysis for condition monitoring application. In: Proceedings of the 1l th National Conference on Machines and Mechanism, 18-2 December, lit Delhi, New Delhi, Allied Publishers Pvt. Limited, pp [6] Harris CG, Williams JH, Davies A (1989) Condition monitoring of machine tools. Int J Prod Res 27 (9): [7] Wang Y, Jia Y, Yu J, Zheng Y, Yi S (1999) Failure probabilistic model of CNC lathes. Reliab Eng Syst Safety 65(3): [8] Wang Y, Jia Y, Jiang W (21) Early failure analysis of machining centres: case study. Reliab Eng Syst Safety 72(1):91-97 [9] Dai Y, Jia Y (21) Reliability of a VMC and its improvement. Reliab Eng Syst Safety 72(1):99-12 [1] Johansson KE (1981) Field monitoring of NC-machines - a system approach in innovation for maintenance technology improvements. In: Proceedings of the Society for Machinery Failure Prevention Group (MFPG) 33rd Meeting, All rights Reserved 151