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

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

INVESTIGATION OF CREEP RESPONSES OF SELECTED ENGINEERING MATERIALS

Mechanical Testing, a concept totally ignored previously, is now a major area of concern. Before now, the concept of testing was merely an afterthought of the procurement process. With the advent of science and technology especially of the type seen in our today’s world, the concept of testing is now an integral part of research and development, product design and manufacturing. This work investigated the creep responses of selected engineering materials (Lead, Polypropylene, and Aluminum alloy samples). Procedure for creep testing and analysis of creep properties of engineering materials from test data are reviewed. The experimental results reveal that the creep resistance of PP was the least with a creep rate of 1.66x10-3 min-1 at 33 OC and 14.22 MPa. Typical values of Creep Strain Rates obtained are 23.5x10-3 min-1 for Pb (BS 1178) at 33 OC and 10.34 MPa; and 4.8X10-6 hr-1 for Wrought Al alloy at 200 oC and 54.58 MPa

DEVELOPMENT OF A 0.5KW HORIZONTAL AXIS WIND TURBINE

Wind turbine is a machine that is powered by the energy from the wind. It is designed to convert the kinetic energy from the wind into electrical power (electricity). This study focus on the development of 0.5KW horizontal axis wind turbine. The major components of the wind turbine which include the blades, hub, shaft and the tower, were design and fabricated to meet the required 0.5 KW and the turbine was mounted on a tower height of 5m from the sea level. The test result showed that the wind turbine is capable of producing about 500 W, at a rotor speed of 153.5 rpm. The necessary design details that have been applied at the design and fabrication stages of the wind turbine guarantees the high hope of this wind turbine performing better

EVALUATION OF CHATTER VIBRATION FREQUENCY IN CNC TURNING OF 4340 ALLOY STEEL MATERIAL

In this study, an experimental investigation of chatter in CNC turning for 4340 Alloy Steel material was carried out. Empirical study of chatter and critical cutting condition in CNC turning has been conducted through a well- designed three-factor three-level experiment, and regression models developed for chatter frequency prediction with up to 99.5% accuracy for the material. The arising model and the mean-effect plots of the cutting speed, feed rate, and depth of cut against Signal-to-Noise (S/N) ratio indicates that increasing feed rates and depth of cuts would bring about increase in chatter vibration frequency while high cutting speeds would have attenuating effects on chatter vibration frequency, thereby suppressing it. The percentage contribution of the cutting parameters to chatter vibration frequency established, and optimal machining condition for the machine chatter optimization obtained at a cutting speed of 320 m/min, feed rate of 0.05mm/rev and depth of cut of 0.5mm. The optimal chatter vibration frequency for the turning tests was found to be 130.00 Hz. With the obtained optimum input parameters for chatter vibration frequency, production operations will be enhanced

DEVELOPMENT OF A 0.5KW HORIZONTAL AXIS WIND TURBINE

Wind turbine is a machine that is powered by the energy from the wind. It is designed to convert the kinetic energy from the wind into electrical power (electricity). This study focus on the development of 0.5KW horizontal axis wind turbine. The major components of the wind turbine which include the blades, hub, shaft and the tower, were design and fabricated to meet the required 0.5 KW and the turbine was mounted on a tower height of 5m from the sea level. The test result showed that the wind turbine is capable of producing about 500 W, at a rotor speed of 153.5 rpm. The necessary design details that have been applied at the design and fabrication stages of the wind turbine guarantees the high hope of this wind turbine performing better

Design, Construction and Evaluation of a Cylinder Lawn Mower

A manually operated mechanical machine for cutting grass was design, fabricated and tested. The machine was design with an internal gear system which transfers the torque to the mower mechanism. The machine's performance test evaluation was conducted in delta state sports stadiwn Asaba. Area of grass cut 2.1 m2 , desired height of cut 20m, time taken 2 min, area of grass cut to desired height 1.92 m2 which gave the cutting efficiency of the cylinder lawn mower 91% with 0.244 KN hwnan effort were obtained. The cutting effectiveness was achieved with a total power of 579.6 W at a rotary speed of 135 rpm of shaft. Its friendly to the environment because it does not emits carbon monoxide into the environment and the noise level is drastically reduced. The machine is considered highly efficient and is readily adaptable to different cutting conditions

Design and Implementation of 0.5kw Horizontal Axis Wind Turbine for Domestic Use

Due to the high demands of energy with the speedy diminishing of fossil fuel assets and the ecological difficulties related with the application of fossil fuel which gave rise to development of alternative energy sources such as wind turbine for power generation in Nigeria. Wind turbine is a machine that is powered by the wind; it is designed to convert the kinetic energy from the wind into mechanical energy and the produces electricity. This study focuses on the design and implementation of 0.5KW horizontal axis wind turbine for domestic usage. It was mounted on a tower height of 5m from the sea level. The major components of the wind turbine which include the blades, hub, shaft and the tower, were machined and fabricated to meet the required 0.5 KW of the wind turbine. The test results showed that the wind turbine is capable of producing about 515 W, at a rotor speed of 153.5 rpm. The necessary design details that have been applied at the design and fabrication stages of the wind turbine guarantees the high hope of this wind turbine performing better in Nigeria

Criticality of Computer Aided Design Packages in Engineering Education & Professionalism for the Developing Countries

Engineers all over the world are known for their creativity, innovations and ingenuity in harnessing the resources and forces of nature for the benefit of mankind. No doubt, engineers in some parts of the world have done so well in view of their giant and mind throbbing technological breakthroughs, while some other parts of the world are at the receiving end of the products of engineering technology. This paper underscores the importance of Computer Aided Design (CAD) in Engineering while calling for a wake-up and real-time embracement of CAD technology by the developing countries. The objective is to re-echo the indisputable fact that CAD represents the most critical part of modern engineering training curricula and by extension, the most important aspect of engineering professionalism. The need to step-up academic training of CAD systems users to better align and measure-up with continuing evolutions in modern day CAD driven engineering is summarily emphasized

Effects of Process Parameters on Vibration Frequency in Turning Operations of Perspex Material

Effects of process parameters on vibration frequency of Perspex round plastic bars was investigated experimentally under clamped - free (C - F) boundary condition during turning operation. Mathematical models were developed using Taguchi L9 orthogonal array design. Spindle speed (V), feed rate (f), and depth of cut (d) were selected as input variables in order to predict the effects of vibration frequency on the work-piece. Nine samples were run in a CNC lathe machine, and each of the experimental result was measured using DTO 32105 frequency analyser and a MXC-1600 digital frequency counter. A minimum vibration frequency of 104.8 Hz was obtained at a cutting speed of 320 m/min, feed rate 0.05 min/rev and at a depth of cut of 0.5 mm. The mathematical model developed shows the accuracy of predicting the vibration frequency to be 99.5% and the various combinations of parameters that results in the minimum vibration frequency were determined. Obtained optimum input parameters for vibration frequency indicated that production operations of Perspex round plastic bars could be enhanc

Experimental and Mathematical Modeling for Prediction of Tool Wear on the Machining of Aluminium 6061 Alloy by High Speed Steel Tools

In recent machining operation, tool life is one of the most demanding tasks in production process, especially in the automotive industry. The aim of this paper is to study tool wear on HSS in end milling of aluminium 6061 alloy. The experiments were carried out to investigate tool wear with the machined parameters and todevelopedmathematicalmodelusingresponsesurface methodology.Thevariousmachiningparametersselected fortheexperimentarespindlespeed(N),feedrate(f),axialdepthofcut(a)andradialdepthofcut(r).Theexperimentwasdesignedusingcentralcompositedesign(CCD) inwhich31sampleswererunonSIEG3/10/0010CNCend milling machine. After each experiment the cutting tool wasmeasuredusingscanningelectronmicroscope(SEM). Theobtainedoptimummachiningparametercombination arespindlespeedof2500rpm,feedrateof200mm/min, axialdepthofcutof20mm,andradialdepthofcut1.0mm wasfoundouttoachievedtheminimumtoolwearas0.213 mm. The mathematical model developed predicted the toolwearwith99.7%whichiswithintheacceptableaccuracyrangefortoolwearpredictio