In any manufacturing industry, machine tools play an important role in the production of parts. The dimensional accuracy and surface finish of the workpiece depends mainly on the condition of the machine. The vibration signatures for different arrangement are recorded to determine the dynamic characteristics of the system, which include workpiece, tool and lathe components. These vibration signatures are analyzed to determine causes of inaccuracy in the manufacturing process and faulty components. Many condition monitoring techniques are available to monitor the machine tool experimentally. Among these techniques, vibration monitoring is the most widely used technique because most of the failures in the machine tool could be due to increased vibration level. Experimental vibration analyses are conducted for a lathe system to detect the possibility of faults and to develop accurate cutting process. Experiments are carried out using the condition monitoring instrument, Vibrometer, to measure vibration severity for different cutting speed, depth-of-cut and feed rate. The value of vibration (rms and peak) at tool post and at bearing is determined from the experimental analyses. It is found that the vibration velocity increases at the cutting speed, depth-of-cut and feed rate increases.

The modern trend of machine tool development is required to produce precise, accurate and reliable products, which are gradually becoming more prominent features. In a machining operation, vibration is a frequent problem which affects the machining performance and, in particular, the surface finish and tool life. Severe vibration occurs in the machining environment due to a dynamic motion between the cutting tool and the workpiece. The monitoring of manufacturing processes and equipment conditions are the essential part of a critical strategy that drives manufacturing industries towards being leaner and more competitive. Many sensors were used for tool condition monitoring system, namely, touch sensors, power sensors, vibration sensors, temperature sensors, force sensors, vision sensors, flow sensors, acoustic emission sensors and so on. All operating machines having rotary and/or reciprocating parts give rise to vibration. Machine tools are liable to deterioration in their performance level with respect to time due to various causes such as wear and tear, ageing, unbalance, looseness of parts, etc., and produce a corresponding increase of the vibration level. Machine tool vibration, if uncontrolled, can adversely affect the surface finish, dimensional accuracy and tool life. About 70% of the failures in the machine tool could be due to increased vibration level of the machine. Lathe is one of the most important machine tools in manufacturing industries. A bearing is the most common critical component in a Lathe. Proper performance and functioning of bearings has always been a major concern in rotating machinery, since all the forces are transmitted to the bearings. It has been well established that 80% of the bearings failed to attain their expected life. A defect in the spindle bearing and unbalance forces in a lathe will induce more vibration, which results in deterioration of the dimensional accuracy and surface finish of the workpiece. The extraction of vibratory signatures can be a valuable diagnostic tool to predict impending failures of the bearing and tool post. In all the cutting operations like turning, boring and milling, vibrations are induced due to the deformation of the workpiece, machine structure and cutting tool. Today, the standard procedure adopted to avoid vibration during machining is by careful planning of the cutting parameters and damping of cutting tool.

Mechanical Engineering Journal, Vibrometer, Cutting tool vibration, RMS value, Peak value.