Papers by Keyword: Dry Turning

Abstract: Sustainable material processing is the current need of machine tool industries. This paper aims to design and experimentally study the material removal rate of mild steel during dry turning using a high-speed steel single point cutting tool and a conventional lathe machine. Twenty-seven turning operations are designed using an orthogonal array experimental design method. The speed, feed and depth of cut are selected as input parameters while material removal rate is considered as quality parameter. Input parameters are varied twenty-seven times during dry turning of mild steel workpieces. Effects of input parameters are investigated to discover which one has a significant effect on material removal rate and hence to determine the dry turning conditions for mild steel. Statistical test results revealed that the depth of cut is significant than feed and speed. The F-value obtained from ANOVA result and Pareto chart are verified that depth of cut is significant on material removal rate of mild steel during dry turning

Abstract: Dry turning operations are required to be performed during production to achieve sustainable development goals as per environmental protection guidelines. In such machining operations, there is no need of supply of mineral based cutting fluids (MBCF) which creates problems of environment contamination and health risks to operators such as lung cancer, eye irritation and skin diseases etc. Al1070 alloys are currently used in construction industry, transport, communication cables and refrigerator cabinets as light weight structural material. The main objectives of the present study are to explore the dry turning operation (without use of MBCF) using Al1070 alloy. The X-ray fluorescence elemental analysis was performed to check composition of MBCF. Several harmful elements such as phosphorus, chlorine, and zinc dialkyl dithiophosphate were present which create high health risk to operators in turning operation with MBCF. The work piece, the cutting tool, the electricity consumption, and the recycling of the chips during the turning process contributed to the total carbon emissions. Significant positive impacts on environment have been achieved in dry turning operation as compared to tuning with MBCF. 19.85% reduction in carbon emissions and 37.12% reduction in tool temperature were achieved in dry turning operation with minimal tool wear and surface defects.

Abstract: This paper presents a research conducted in order to identify the cutting parameters effect on turning cutting forces and on the resulted machined surface quality for a CoCrWNi alloy. This alloy is a biomaterial used in medical applications for implants manufacturing. The main objective of the research is the development of prediction models for the turning cutting forces and the Ra roughness parameter for dry longitudinal turning with TiAlN PVD coated inserts. In order to achieve this objective, thirteen processing experiments were carried out, during which the cutting forces and roughness parameters were registered. The research results consist of the prediction models for cutting forces and Ra roughness parameter.

Abstract: This paper reports the development of a cutting tool insert prepared by consolidation, followed by Spark Plasma Sintering (SPS) of TiB₂ (Titanium diboride) particles processed through an in-situ reaction and AlN (Aluminium nitride) manufactured by the direct nitridation process. In-situ TiB₂ particles, formed during reaction of KBF₄ (Potassium tetra Fluoroborate) and K₂TiF₆ (Potassium Fuorotitanate) with Al alloy, are obtained by dissolving the Al-TiB₂ composite in an acidic medium. The extracted TiB₂ (30%) particles are blended with AlN and Al₂O₃ in the weight ratio of 67%-3% and sintered (SPS) at 1440°C with a compaction load of 50 MPa and a total sintering time of 8 minutes. The sintering is carried out in vacuum. The sintered ceramic displays high hardness of nearly 15.5 GPa and extraordinary toughness of 7MPa.m^1/2. The inserts are manufactured according to SNGN (Square Double-sided ceramic) configuration. To study its performance, machining is carried out on hardened steel (EN 24). The developed AlN based inserts show increased wear resistance and provide good surface finish when compared with commercially available ceramic inserts (70%Al₂O₃+30%TiC). Cutting forces are recorded with a Kistler® dynamometer to correlate them with the tool wear. Methods of preparation and comparison of wear resistance and surface finish of the machined material with those pertaining to commercial ceramic inserts are also presented. SEM images are displayed, which support the results.

Abstract: The use of short process chains for the realization of complex and high performance components is a reasonable approach to achieve sustainable products and to reduce energy consumption. In the Collaborative Research Center SFB/TR TRR30 which is supported by the German Research Foundation DFG this approach is investigated applying thermo-mechanically forming processes. In this way, combining hot metal forming and heat treatment steps in a single process, tailored materials properties together with appropriate geometries are achieved [1, 2] . However, still additional machining operations, e. g. turning operations in case of shafts, are needed to achieve proper workpiece finish. Due to locally varying mechanical properties, undesired changings of the process conditions occur, leading to varying surface and subsurface properties, e.g. the residual stress state. It is well known that residual stresses have a major impact on the components properties during service [3]. In this paper, a survey is given about near surface residual stress states after exterior dry turning of differently heat treated cylindrical workpieces made of steel AISI 6150.

Abstract: The influence of the forming process in the response into service of the manufactured workpieces, in the first instance, through the surface integrity can be evaluated. The concept of surface integrity includes the assessment of geometrical aspects like shape and dimensions, and physicochemical properties like hardness and corrosion resistance. This work reports on the results of a study of the influence of the turning parameters on the Ultimate Tensile Strength (UTS) of turned bars of UNS A92024 Aluminium-Copper alloy.

Abstract: With increasing quantities of applications of Metal Matrix Composites (MMCs), the machinablity of these materials has become important for investigation. This paper presents an investigation of surface roughness and tool wear in dry machining of aluminium LM6-TiC composite using uncoated carbide tool. The experiments carried out consisted of different cutting models based on combination of cutting speed, feed rate and depth of cut as the parameters of cutting process. The cutting models designed based on the Design of Experiment Response Surface Methodology. The objective of this research is finding the optimum cutting parameters based on workpiece surface roughness and cutting tool wear. The results indicated that the optimum workpiece surface roughness was found at high cutting speed of 250 m min^-1 with various feed rate within range of 0.05 to 0.2 mm rev^-1, and depth of cut within range of 0.5 to 1.5 mm. Turning operation at high cutting speed of 250 m min^-1 produced faster tool wear as compared to low cutting speed of 175 m min^-1 and 100 m min^-1. The wear minimum (VB = 42 μm ) was found at cutting speed of 100 m min^-1, feet rate of 0.2 mm rev^-1, and depth of cut of 1.0 mm until the length of cut reached 4050 mm. Based on the results of the workpiece surface roughness and the tool flank wear, recommended that turning of LM6 aluminium with 2 wt % TiC composite using uncoated carbide tool should be carried out at cutting speed higher than 175 m min^-1 but at feed rate of less than 0.05 mm rev^-1 and depth of cut less than 1.0 mm.

Abstract: The use of magnesium alloys in construction of different components of the mechanical systems (such: cars, aerospace vehicles, medical equipment etc.) is very efficient not only because it leads to reduction of the systems weight but also because it leads to reduction or elimination of the environment polluting and to reduction of the energy consumption. Generally, the main factors that influence the quality of the machined surfaces are as follows: cutting parameters, material properties, geometry of the tools, cooling liquids and lubricants, physical and mechanical properties of the subsurface layers etc. Among the above mentioned factors, cutting parameters are the factors that strongly influence the quality of the machined surfaces. The present paper analysis the results of the experimental investigation performed to determine the influence of cutting parameters (cutting speed, feed rate and cutting depth) on the surface quality machined by turning the AZ61 magnesium alloy. The main characteristics of the machined surface quality analyzed in experimental investigation were the surface roughness and hardness. The main conclusions resulted from the results analysis were as follows: the decrease of the feed rate led to surface roughness decrease and hardness increase; the increase of the cutting speed also led to an improved surface quality.

Abstract: Performance of machining processes is assessed by dimensional and geometrical accuracy which is mentioned in this paper as dimensional deviation. A part quality does not depend solely on the depth of cut, feed rate and cutting speed. Other variable such as excessive machine tool vibration due to insufficient dynamic rigidity can be deleterious to the desired results. The focus of the present study is to find a correlation between dimensional deviation against cutting parameters and machine tool vibration in dry turning. Hence cutting parameters and vibration-based regression model can be established for predicting the part dimensional deviation. Experiments are conducted using a Computerized Numerical Control (CNC) lathe with carbide insert cutting tool. Vibration data are collected through a data acquisition system, then tested and analyzed through statistical analysis. The analysis revealed that machine tool vibration has significant effect on dimensional deviation where statistical analysis of individual regression coefficients showed p<0.05. The developed regression model has been validated through experimental tests and found to be reliable to predict dimensional deviation.

Abstract: The present work shows an experimental study for a first approach of a surface roughness predictive model of UNS A97075 aluminum pieces obtained by dry turning tests based on the cutting forces. In a first step, a design of experiments (DOE) 25 was employed to analyse the influence of the cutting parameters and type of tool on the surface roughness with the objective to find out a combination of cutting conditions that allow obtaining a range of values of surfaces roughness according to the aeronautical specifications requierements. The factors considered for this design were the feed rate, spindle speed, depth of cut, type of tool (nose radious) and machined length (zone of the workpiece where the surface roughness measurements are taken). The obtained data was analysed by means of the analysis of variance (ANOVA) method. And secondly, with the previous selected conditions selected it was developed by multiple regression a model to predict the surface roughness by measuring the cutting forces generated during the dry turning tests of aluminum alloy UNS A97075 pieces. The predictive model of surface roughness obtained includes statistical values calculated from the forces sygnal in time and frequency domains.