Thermal hardening and calculation of the mathematical model of face milling of parts made of steel 95X18-Sh to improve the quality of the surface layer

2021 ◽  
pp. 200-206
Author(s):  
I.N. Sedinin ◽  
V.F. Makarov

It is considered the complex of operations of the technological process for the heat treatment of steel 95X18-Sh, as a result of which the material of the samples increases the hardness to 59...61 HRC, and also improves the physical and mechanical properties. A full-scale full factorial experiment of face milling of samples was carried out using the method of mathematical planning. In the experiments, a high-precision machine and a carbide cutting tool were used. To calculate the values of the roughness function, the following are taken as independent variables: cutting speed, feed per tooth and depth of cut. In order to determine the coefficients of the linear equation, a central compositional orthogonal plan of the second order for three factors was used. A matrix of levels of variation of independent variable factors and a matrix of experiment planning were compiled. A regression analysis of the obtained experimental statistical data was carried out using the Microsoft Excel, Statistica and Wolfram Alpha programs. As a result of the calculations, a mathematical model of the roughness of the machined surface and optimal cutting conditions were determined.

Author(s):  
Volodymyr Rutkevych

The possibility of improving the quality of rubber due to the directional action of various types of ultrasonic vibrations, with the aim of forming the maximum compressive residual stresses, will ultimately improve the performance of the rize joint under variable loads. The process of rizenization using forced ultrasonic vibrations has been investigated. When compiling a mathematical model of the process of extrusion of rubber with the imposition of ultrasonic vibrations on the tool, it was assumed that the phenomenon of surface hardening has little effect on the magnitude of the contact pressure and the friction force during plastic deformation. This assumption allows us to simplify the mathematical model by not taking into account this factor. New methods of calculating the contact pressure and specific frictional force during rubber extrusion with the imposition of axial, radial and torsional vibrations are proposed. The description of the deformation processes with the superposition of ultrasonic vibrations was carried out on the basis of the rheological model of deformation of an ideal elastic-plastic body. The work developed nonlinear mathematical models for the study of plastic deformation processes, consisting of equations of tool displacement and equations taking into account the elastic-plate properties of the processed material. This structure of the mathematical model most fully reflects the processes occurring during thread rolling with the imposition of ultrasonic vibrations. As a result of the research, it has been established that the use of forced ultrasonic vibrations during machining with a tool will significantly increase the productivity, tool durability and quality of the processed surface, especially when processing with special physical and mechanical properties. In the study of the contact interaction of the tool with the part with the imposition of ultrasonic vibrations in the axial and radial directions, as well as in the imposition of torsional vibrations, it was found that the use of axial vibrations is on average 50 % more effective.


2020 ◽  
Vol 184 ◽  
pp. 01013
Author(s):  
Kosaraju Satynarayana ◽  
Are Swathi ◽  
Kesari Neeraja ◽  
Madipali Samaikhya ◽  
Kumkuma Rajkiran

Turning is one of the initial basic machining operation that prevails in assembly and production process. Modern techniques have been practices in rapid and eco-friendly production systems. Present study deals with the investigation of turning process on EN 18 steel which is been shown its existence in automobiles industries. Turning operation was performed using a coated tool insert with varying cutting speed (100, 125 and 150 mm/min), feed rate (0.05, 0.5, 0.15 mm/rev) and depth of cut (0.4, 0.8, 1.2 mm) at both dry and MQL conditions. The results obtained was compared to optimize the effect of minimum quality lubrication on surface roughness. Experimentally it was observed that speed of 100 m/min with combination of feed of 0.05 mm/rev and 0.4 mm depth of cut was found to be optimized for surface roughness in both the cases. The mathematical model generated for surface roughness and MRR for both dry and MQL turning models having better regression fit as it closer to 100. From ANOVA analysis feed was proved to be the highest contributing factor for surface roughness and for MRR speed is the most significant factor for both dry and MQL turning


Author(s):  
Pavana Kumara ◽  
G. K. Purohit

Roller burnishing process was carried out on free cutting brass materials in the presence of fine silicon carbide abrasives in the form of paste on a pre-machined surface. The results of ‘without-paste’ burnishing (plain burnishing, PB) and ‘with-paste’ burnishing (abrasive assisted burnishing, AAB) processes are compared to examine the effect of abrasive particles in the burnishing process. A 24 full factorial design is adopted to develop the mathematical model for surface roughness regarding four process parameters like burnishing force, burnishing speed, burnishing feed and number of passes for both the cases, i.e. PB and AAB. Analysis of variance (ANOVA) was carried out to find the effect of process parameters and to check the adequacy of the models. The results show that the parameters have a significant effect on the response in PB to improve the surface roughness by 75 % than the turned components. Whereas in AAB, fine abrasive particles as a single entity controlling the response and making other parameter effects as non-significant. Surface roughness further improved by 15 % in AAB process.


2020 ◽  
Vol 10 (5) ◽  
pp. 1788
Author(s):  
Michal Šajgalík ◽  
Milena Kušnerová ◽  
Marta Harničárová ◽  
Jan Valíček ◽  
Andrej Czán ◽  
...  

Current demands on quality are the engine of searching for new progressive materials which should ensure enough durability in real conditions. Due to their mechanical properties, however, they cannot be applied to conventional machining methods. In respect to productivity, one of the methods is the finding of such machining technologies which allow achieving an acceptable lifetime of cutting tools with an acceptable quality of a machined surface. One of the mentioned technologies is trochoidal milling. Based on our previous research, where the effect of changing cutting conditions (cutting speed, feed per tooth, depth of cut) on tool lifetime was analysed, next, we continued with research on the influences of trochoid parameters on total machining force (step and engagement angle) as parameters adjustable in the CAM (computer-aided machining) system. The main contribution of this research was to create a mathematical-statistical model for the prediction of cutting force. This model allows setting up the trochoid parameters to optimize force load and potentially extend the lifetime of the cutting tool.


2015 ◽  
Vol 1105 ◽  
pp. 93-98
Author(s):  
Adnan I.O. Zaid ◽  
S.M.A. Al-Qawabah

Shape memory alloys (SMAs) are now widely used in many industrial and engineering applications e.g. in aircrafts, space vehicles, robotics and actuators. However the available literature reveals that little or no work is published on the machinability of these alloys. In this paper, the effect of the main cutting parameters namely: cutting speed, depth of cut and feed rate on the surface quality of the machined surface of the Cu-Zn-Al shape memory alloy both in the cast and after direct extrusion using a CNC milling is investigated. The cutting speed was varied from 750 to 2000 rpm , the depth of cut was varied from 1 to 4 mm and the feed rate was varied from 100 to 250 mm/min. Furthermore, the general microstructure, the mechanical behavior and hardness of the Cu-Zn-Al shape memory alloy both in the cast and after direct extrusion are determined and discussed. It was found that the best achieved surface quality in this SMA, machined within the different investigated cutting conditions is 0.13 microns at cutting speed of 750 rpm, 1 mm depth of cut and 150 mm/min. feed rate, which is better than the surface quality achieved in other materials at the same cutting conditions.


2012 ◽  
Vol 426 ◽  
pp. 339-343 ◽  
Author(s):  
Qiu Lin Niu ◽  
X.J. Cai ◽  
Zhi Qiang Liu ◽  
Ming Chen ◽  
Qing Long An

As a typical high strength material, titanium alloy Ti-6Al-2Sn-4Zr- 2Mo-0.1Si (TA19) is used to manufacturing the compressor power-brake of aircraft engine and the aircraft skin. All the machining experiments were carried out on a CNC-milling center under the stable conditions of cutting speed, feed rate, and depth of cut. The performance and wear mechanisms of coated- and uncoated carbide tools have been investigated in this paper to evaluate the machinability of TA19 in face milling. The three tools used were PVD-TiN+TiAlN, CVD-TiN+Al2O3+TiCN and uncoated carbide inserts. The results indicated that PVD coating had the best performance than other tool materials in milling titanium alloy TA19, and the cutting force and the wear value were the smallest than that for CVD-coated and uncoated tools. The failure types of PVD-, CVD- and uncoated inserts were the crater wear and micro tipping; the crater wear and tipping; tipping. Abrasive wear and adherent wear were the predominant mechanism of PVD-TiN+TiAlN carbide insert in face milling TA19 alloy. For CVD- and uncoated carbide, adherent wear was predominant.


Author(s):  
P. Singh ◽  
J. S. Dureja ◽  
H. Singh ◽  
M. S. Bhatti

Machining with minimum quantity lubrication (MQL) has gained widespread attention to boost machining performance of difficult to machine materials such as Ni-Cr alloys, especially to reduce the negative impact of conventional flooded machining on environment and machine operator health. The present study is aimed to evaluate MQL face milling performance of Inconel 625 using nano cutting fluid based on vegetable oil mixed with multi-walled carbon nanotubes (MWCNT). Experiments were designed with 2-level factorial design methodology. ANOVA test and desirability optimisation method were employed to arrive at optimised milling parameters to achieve minimum tool wear and machined surface quality. Experiments were performed under nanoparticles based minimum quantity lubrication (NMQL) conditions using different weight concentrations of MWCNT in base oil: 0.50, 0.75, 1, 1.25 and 1.5 wt. %; and pure MQL environment (without nanoparticles). The optimal MQL milling parameters found are cutting speed: 47 m/min, table feed rate: 0.05 mm/tooth and depth of cut: 0.20 mm. The results revealed improvement in the surface finish (Ra) by 17.33% and reduction in tool flank wear (VB) by 11.48 % under NMQL face milling of Inconel 625 with 1% weight concentration of MWCNT in base oil compared to pure MQL machining conditions.


2015 ◽  
Vol 3 (2) ◽  
Author(s):  
Syed Adnan Ahmed ◽  
Jeong Hoon Ko ◽  
Sathyan Subbiah ◽  
Swee Hock Yeo

This paper describes a new method of microtexture generation in precision machining through self-excited vibrations of a diamond cutting tool. Conventionally, a cutting tool vibration or chatter is detrimental to the quality of the machined surface. In this study, an attempt is made to use the cutting tool's self-excited vibration during a cutting beneficially to generate microtextures. This approach is named as “controlled chatter machining (CCM).” Modal analysis is first performed to study the dynamic behavior of the cutting tool. Turning processes are then conducted by varying the tool holder length as a means to control vibration. The experimental results indicate that the self-excited diamond cutting tool can generate microtextures of various shapes, which depend on the cutting tool shank, cutting speed, feed, and cutting depth. The potential application of this proposed technique is to create microtextures in microchannels and microcavities to be used in mass and heat transfer applications.


Open Physics ◽  
2018 ◽  
Vol 16 (1) ◽  
pp. 57-62 ◽  
Author(s):  
Sebastian Różowicz

Abstract The paper presents the results of analytical and experimental studies concerning the influence of different kinds of fuel additives on the quality of the spark discharge for different configurations of the ignition system. The wear of the spark plug electrode and the value of spark discharge were determined for various impurities and configurations of the air-fuel mixture.


Author(s):  
Prashant S Jadhav ◽  
Chinmaya P Mohanty

Nimonic C-263 is predominantly used in the manufacturing of heat susceptible intricate components in the gas turbine, aircraft, and automotive industries. Owing to its high strength, poor thermal conductivity, the superalloy is difficult to machine and causes rapid tool wear during conventional machining mode. Moreover, the unpleasant machining noise produced during machining severely disrupts the tool engineer’s concentration, thereby denying a precise and environment friendly machining operation. Hence, close dimensional accuracy, superior machined surface quality along with production economy, and pleasant work environment for the tool engineers is the need of an hour of the current manufacturing industry. To counter such issues, the present work attempts to compare and explore the machinability of two of the most popular machining strategies like minimum quantity lubrication (MQL) and cryogenic machining process during turning of Nimonic C-263 work piece in order to achieve an ideal machining environment. The machining characteristics are compared in terms of surface roughness (SR), power consumption (P), machining noise (S), nose wear (NW), and cutting forces (CF) to evaluate the impact of machining variables like cutting speed (Vc), feed (f), and depth of cut (ap) with a detailed parametric study and technical justification. Yet again, an investigation is conducted to compare both the machining strategies in terms of qualitative responses like chip morphology, total machining cost, and carbon emissions. The study revealed that cryogenic machining strategy is adequately proficient over MQL machining to deliver energy proficient and gratifying work environment for the tool engineers by reducing the cost of machining and improving their work efficiency.


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