Effect Of Cutting Parameters On Surface Roughness Of Mild Carb On Steel During Operation

Description

ABSTRACT

In every machining operations, surface finish is an essential characteristic of concern for many of the turned workpieces. So it is very important for getting the required surface quality controlled to have the choice of optimized cutting factors. In the present experimental  work  the  optimization of cutting factors (depth of cut, feed rate, spindle speed) has been done in    dry turning of mild steel of (0.21% C). In the present work, turning operations were carried    out on mild steel by high speed steel cutting tool in dry condition and the combination of the optimal levels of the factors was obtained to get the lowest surface roughness.  The Analysis    of Variance (ANOVA) and Signal-to-Noise ratio were used to study the performance characteristics in turning operation. The results of the analysis show that depth of cut was the only factor found to be significant. Results obtained by Taguchi method match closely with ANOVA and depth of cut is most influencing parameter. The predicted values and measured values are fairly close, which depicts that the developed model can be effectively used to predict the surface roughness in the turning operation. ANOVA was used to find out the significant parameters. Feed rate was found to be the most influential factor in increasing the surface roughness and decreasing machining time, whereas Depth of cut is the most influential factor in increasing the avg tool-chip interface temperature.

CHAPTER ONE

1.0                                                        INTRODUCTION

1.1                                           BACKGROUND OF THE STUDY

Dry machining has its advantages and associated drawbacks. The advantages of dry machining are obvious: cleaner parts, no waste generation, reduced cost of machining, reduced cost of chip recycling (no residual oil), etc. and most important is the better surface finish. However, these advantages do come at a cost. The quality of machined parts may be affected significantly as the properties of the machined surface are significantly altered by dry machining in terms of its metallurgical properties and residual machining stresses.

High cutting forces and temperatures in dry machining may cause the distortion of parts during machining. Moreover, parts are often rather hot after dry machining so their handling, inspection gauging, etc., may present a number of problems. Near-dry machining (NDM) formerly known as minimum quantity lubrication (MQL) machining, was developed to provide at least partial solutions to the listed problems with dry machining.

This process uses a minimum quantity of lubrication and is referred to as “near-dry”. In near-dry machining (NDM), an air–oil mixture called an aerosol is fed into the machining zone. Increasing the productivity and the quality of the machined parts are the main challenges of metal cutting industries. Compared to dry machining, NDM substantially enhances cutting performance in terms of increasing tool life and improving the quality of the machined parts. The growing demands for high productivity and quality of turned parts in terms of surface finish and less time for machining need use of high cutting velocity. Such machining inherently produces high cutting temperature, which not only reduces tool life but also impairs the product quality. Small oil droplets carried by the air fly directly to the tool working zone, providing the needed cooling and lubricating actions. Because MWF cannot be seen in the working zone, and because the chips look and feel dry, this application of minimum-quantity lubricant is called near-dry machining. In short, NDM delivers a very small amount of coolant to a cutter’s edge in the form of an oil mist or aerosol, as opposed to traditional techniques of flooding the workpiece and tool with a substantial volume of liquid coolant. Just a tiny bit of that aerosol is left on the chips, workpiece and machine during the cutting operation.

1.2                            OBJECTIVES OF THE PROJECT

The objectives of this research are:

1. Knowing the level of surface roughness of carbon steel S45C result of cutting in lathe process based on variations of spindle speed, feed rate and depth of cut using cutting tools insert tip Finishing.
2. Provides parameter setting information for spindle speed, feed rate and depth of cut on the resulting surface roughness level.

1.3                                  SCOPE OF THE PROJECT

On the machining operation, the quality of surface finish is an important requirement for many turned workpieces. In the process of cutting using a lathe, the selection of appropriate cutting parameters is essential to control the required surface quality. Thus, the choice of optimized cutting parameters is very important for controlling the required surface quality. In some industrial places, there are many difficulties to create components according to the demands of the working drawings. Machine operators usually use “trial and error” approaches to set-up machine cutting conditions in order to achieve the desired surface roughness. Obviously, the “trial and error” method is not effective and efficient and the achievement of the desired value is a repetitive and empirical process that can be very time-consuming. The dynamic nature and widespread usage of cutting operations in practice have raised a need for seeking a systematic approach that can help to set-up cutting operations in a timely manner and also help achieve the desired surface roughness quality.

1.5                          SIGNIFICANCE OF THE PROJECT

This study will help machine operator in increasing the work surface smoothness and decreasing machining time

1.6                                           PROJECT ORGANISATION

The work is organized as follows: chapter one discuses the introductory part of the work,   chapter two presents the literature review of the study,  chapter three describes the methods applied,  chapter four discusses the results of the work, chapter five summarizes the research outcomes and the recommendations.

CHAPTER TWO

2.0                                    LITERATURE REVIEW

2.1                                OVERVIEW OF THE STUDY

As a basic machining process, lathing is one of the most widely used metal removal processes in industry and lathe surfaces are largely used to mate with other parts in die, aerospace, automotive, and machinery design as well as in manufacturing industries [1, 2]. Surface roughness is an important measure of the technological quality of a product and a factor that greatly influences manufacturing cost. Lathe is one of the most reliable production machines by the manufacturing industry in producing its products. The product quality of the lathe process is determined by the degree of roughness of the surface. In the process of cutting metal using lathe the result of roughness is determined by three main parameters, namely movement of workpiece / spindle main motion, feed motion and depth of depth cut [3]. While other researchers said that the parameters that determine the surface roughness is the depth of cut, feed rate and cutting speed [4]. Suresh et al. [5], investigated effects of cutting speed, feed rate, depth of cut and machining time on cutting forces, tool wear and surface…