The Wheel Wear and Metal Removal Mechanisms in Vertical Spindle Abrasive Machining of Mild Steel

1968 ◽  
Vol 90 (2) ◽  
pp. 365-369 ◽  
Author(s):  
C. Pollock

The primary metal removal mechanisms in vertical spindle abrasive machining are chip removal by firmly bonded abrasive grains in the wheel matrix, and secondary removal by the reuse of loose abrasive between the wheel-work interface. As you increase the strength (go to harder grades) of segments, the secondary metal removal rate tends to remain constant. However, the metal removed by firmly bonded abrasive increases rapidly. Changing from an E to an F grade approximately doubles the primary metal removal rate. Segmental wheels sharpen themselves by two major mechanisms—primary and secondary wear. Primary wear is caused by the common mechanisms of attrition, grain fracture, and bond failure. The secondary mechanism is caused by loose abrasive and metal chips in the wheel-work interface.

1959 ◽  
Vol 81 (3) ◽  
pp. 187-199 ◽  
Author(s):  
E. J. Krabacher

Optimum utilization of grinding wheels can best be achieved if the nature of their performance and wear characteristics, and the factors that affect these characteristics, are understood and applied. As reported in this paper, a comprehensive, continuing, grinding-research program has contributed to such an understanding. A study of the nature of grinding-wheel wear indicates that the grinding-wheel wear curve is similar to those of other cutting tools. It demonstrates further that the type of grinding operation significantly affects the nature of wheel wear. A unique technique has been developed for very accurately measuring grinding-wheel wear. This measured wear may be translated into terms of “grinding ratio,” which is the generally accepted parameter for measuring wheel wear. It is the ratio of the volume of metal removed per unit volume of wheel worn away. Extensive studies have been carried out to determine the effect of mechanical variables on grinding ratio, power required in metal removal, and on surface finish. Experimental findings indicate that grinding ratio decreases with increased metal-removal rate and increases with workpiece diameter, decreased chip load, and increased concentration of grinding fluid. Power is found to increase with both the metal-removal rate and the amount of metal removed. It increases slightly with workpiece diameter and is affected little by work-material hardness. Surface finish is found to improve with decreased metal-removal rate and decreased chip load. It also is affected little by work diameter or work-material hardness. Fundamental research in the mechanics of wheel wear is supplying much additional information in the study of grinding-wheel wear. The measurement of grinding forces employing a cylindrical grinding dynamometer provides the opportunity for relating the wear of grinding wheels to the basic mechanics of the process through such fundamental quantities as grinding forces, specific energy, and grinding friction. Two additional experimental techniques for the study of chip formation in grinding have also proved to be most useful research tools. A “quick-stop” apparatus is used to freeze the grinding action by accelerating a tiny workpiece almost instantaneously to grinding-wheel speed. Another technique permits the comparison of the shape of the grinding grit and that of the contour of its path through the workpiece by a unique replicating method.


1976 ◽  
Vol 98 (3) ◽  
pp. 1048-1052 ◽  
Author(s):  
R. W. Mayne ◽  
S. Malkin

This paper is concerned with the application of nonlinear programming methods to the surface grinding of steels and considers the specific case of plunge grinding. Performance equations based on a model of the process are presented and then optimized. Trade-off curves are established showing the best metal removal rate possible for given constraints on surface quality and at specified conditions of grinding wheel wear. Optimum values for the various parameters in the grinding process are also included. In addition, the sensitivity of steel grinding performance to nonoptimum choices of grinding wheel velocity and diameter is considered.


1967 ◽  
Vol 89 (2) ◽  
pp. 323-327 ◽  
Author(s):  
C. Pollock

This paper reports the results of a systematic test program designed to determine the effect of work area, downfeed rate, and segment grade on performance on vertical spindle surface grinders. Metal removal rate is shown to be a function of volumetric feed rate only. Wheel wear rate is shown to be a linear function of volumetric feed rate with the slope of each line a function of workpiece area. It is also shown that the effect of segment grade is to vertically displace the metal removal rate, wheel wear rate, grinding ratio, and power curves. The vertical displacement of the metal removal rate, wheel wear rate, and grinding ratio becomes progressively less as the hardness of the segment increases. The effect is reversed for power. The practical significance and application of this information are also discussed, showing examples of how it can be applied to solve certain general problems.


2018 ◽  
Vol 49 (2) ◽  
pp. 62-81 ◽  
Author(s):  
Shailendra Kumar ◽  
Bhagat Singh

Tool chatter is an unavoidable phenomenon encountered in machining processes. Acquired raw chatter signals are contaminated with various types of ambient noises. Signal processing is an efficient technique to explore chatter as it eliminates unwanted background noise present in the raw signal. In this study, experimentally recorded raw chatter signals have been denoised using wavelet transform in order to eliminate the unwanted noise inclusions. Moreover, effect of machining parameters such as depth of cut ( d), feed rate ( f) and spindle speed ( N) on chatter severity and metal removal rate has been ascertained experimentally. Furthermore, in order to quantify the chatter severity, a new parameter called chatter index has been evaluated considering aforesaid denoised signals. A set of 15 experimental runs have been performed using Box–Behnken design of experiment. These experimental observations have been used to develop mathematical models for chatter index and metal removal rate considering response surface methodology. In order to check the statistical significance of control parameters, analysis of variance has been performed. Furthermore, more experiments are conducted and these results are compared with the theoretical ones in order to validate the developed response surface methodology model.


Author(s):  
Rajesh Kumar Bhushan

Optimization in turning means determination of the optimal set of the machining parameters to satisfy the objectives within the operational constraints. These objectives may be the minimum tool wear, the maximum metal removal rate (MRR), or any weighted combination of both. The main machining parameters which are considered as variables of the optimization are the cutting speed, feed rate, depth of cut, and nose radius. The optimum set of these four input parameters is determined for a particular job-tool combination of 7075Al alloy-15 wt. % SiC (20–40 μm) composite and tungsten carbide tool during a single-pass turning which minimizes the tool wear and maximizes the metal removal rate. The regression models, developed for the minimum tool wear and the maximum MRR were used for finding the multiresponse optimization solutions. To obtain a trade-off between the tool wear and MRR the, a method for simultaneous optimization of the multiple responses based on an overall desirability function was used. The research deals with the optimization of multiple surface roughness parameters along with MRR in search of an optimal parametric combination (favorable process environment) capable of producing desired surface quality of the turned product in a relatively lesser time (enhancement in productivity). The multi-objective optimization resulted in a cutting speed of 210 m/min, a feed of 0.16 mm/rev, a depth of cut of 0.42 mm, and a nose radius of 0.40 mm. These machining conditions are expected to respond with the minimum tool wear and maximum the MRR, which correspond to a satisfactory overall desirability.


2018 ◽  
Vol 877 ◽  
pp. 110-117 ◽  
Author(s):  
Poornesh Kumar Chaturvedi ◽  
Harendra Kumar Narang ◽  
Atul Kumar Sahu

Quality of the product is the major concern in manufacturing industries from customers as well as producers point of view. There are number of factors in the product such as surface condition, height, weight, length, width etc., which may be consider for the measurement of the quality. Surface roughness and Metal Removal Rate (MRR) are the two main outcomes on which numerous researchers have applied different approaches for several years to get optimum results. In this study, Taguchi Method is applied for getting optimum parameters settings for Surface roughness and Metal Removal Rate (MRR) in case of turning AlMg3 (AA5754) in CNC Lathe machine, which is an aluminum alloy having diameter 20 mm and length 100 mm. The three parameters i.e. spindle speed, feed rate and depth of cut with 3 levels are taken as the process variables and the working ranges of these parameters for conducting experiments are selected based on Taguchi’s L9 Orthogonal Array (OA) design. To analyze the significant process parameters; main effect plots for data means and for S/N ratio are generated using Minitab statistical software.


Author(s):  
Hossam M Yehia ◽  
Mohamed Hakim ◽  
Ahmed El-Assal

The integrated electrochemical grinding machining has received wide acceptance in the aircraft turbine industry for the machining of blades, vanes, and honeycomb seal rings. Also, medical devices, instruments and forceps, shells, precision nozzles, instrument coupling, and air rotor motors that produced from stainless steel and new materials have all successfully been accomplished with electrochemical grinding. To improve the metal removal rate and to reduce the surface roughness ( Ra) of the electrochemical grinding at high voltages, an integration between the alumina abrasive jet and the electrochemical grinding machining has been performed. The effect of the Al2O3 abrasive content on the metal removal rate and the Ra of the K110 alloy steel using Everite electrochemical grinding 618 at different voltages, different feed rates, different electrolyte NaCl concentrations, and different depths of the cut were successfully investigated. The results revealed that the abrasive electrochemical grinding was better than the electrochemical grinding results. The maximum effect of the Al2O3 on the metal removal rate was achieved at 5 wt.%. The current density in the machining gap was affected by the addition of the Al2O3, where it was decreased at percentages over 5-wt.% Al2O3. The abrasive electrochemical grinding resulted in lower surface roughness than the electrochemical grinding process.


2008 ◽  
Vol 07 (02) ◽  
pp. 337-343 ◽  
Author(s):  
T. SEKAR ◽  
R. MARAPPAN

Electrochemical machining (ECM) is a non-traditional process used mainly to cut hard or difficult to cut metals, where the application of a more traditional process is not convenient. Those difficult to cut metals demand high energy to form chips, which can result in thermal effects due to the high temperatures inherent to the process in the chip–tool interface. In traditional processes, the heat generated during the cut is dissipated to the tool, chip, workpiece and environment, affecting the surface integrity of the workpiece, mainly for those hard materials. In this work, experimental investigations have been made on the various influencing parameters involved in the Metal removal rate (MRR) and Surface roughness using ECM on AISI 202 steel. The major intervening parameters are studied and the relationship between the parameters has been determined to achieve maximum metal removal rate and minimum surface roughness by using NaNO 3-Aqua solution.


Sign in / Sign up

Export Citation Format

Share Document