Ranking of vitrified grinding wheel parameters by using analytical hierarchical process (AHP) for surface roughness of work piece in grinding operation

Objective of grinding process is to generate high quality surface finish on work piece. There are many parameters which influence on the work piece roughness. Work piece material and characteristics, grinding wheel specification, grinding conditions and dressing conditions influence on the surface quality of the work piece. Selection of grinding wheel is important aspect for producing good quality of surface finish on the work piece. The main components of grinding wheel are the abrasive grains, bond material and porosity. Selection of correct grinding wheel is necessary for generating better surface finish on the work piece. Analytical Hierarchical Process (AHP) is used for ranking of vitrified bond grinding wheel parameters on surface roughness on the work piece in sub sequent grinding operation. The grit, grade, (Hardness of wheel) structure and type of abrasive are critically assisted in terms of the surface finish produced on work piece in the subsequent grinding operation. Analytic Hierarchy Process (AHP) shows that the abrasive grit of grinding wheel has first rank and grade (hardness) of the wheel has Second rank for the producing surface finish on the work piece after grinding operation. Structure and type of abrasive of wheel have a third and fourth rank respectively. Thus, AHP gives qualitative way of controlling work piece surface roughness in sub-sequent grinding operation by selecting proper grinding wheel of vitrified bond which helps the user to select the correct grinding wheel

Selection of Levels of Dressing Process Parameters by Using TOPSIS Technique for Surface Roughness of En-31 Work piece in CNC Cylindrical Grinding Machine

Grinding is metal cutting process used for mainly finishing the automobile components. The grinding wheel performance becomes dull by using it most of times. So it should be reshaping for consistent performance. It is necessary to remove dull grains of grinding wheel which is known as dressing process. The surface finish produced on the work piece is dependent on the dressing parameters in sub-sequent grinding operation. Multi-point diamond dresser has four important parameters such as the dressing cross feed rate, dressing depth of cut, width of the diamond dresser and drag angle of the dresser. The range of cross feed rate level is from 80-100 mm/min, depth of cut varies from 10 – 30 micron, width of diamond dresser is from 0.8 – 1.10mm and drag angle is from 40o – 500, The relative closeness to ideal levels of dressing parameters are found for surface finish produced on the En-31 work piece during sub-sequent grinding operation by using Technique of Order Preference by Similarity to Ideal Solution (TOPSIS).In the present work, closeness to ideal solution i.e. levels of dressing parameters are found for Computer Numerical Control (CNC) cylindrical angular grinding machine. After the TOPSIS technique, it is found that the value of Level I is 0.9738 which gives better surface finish on the En-31 work piece in sub-sequent grinding operation which helps the user to select the correct levels (combinations) of dressing parameters

Wear performance optimization of Silicon Nitride using Genetic and simulated annealing algorithm

Replacing damaged joint with the suitable alternative material is a prime requirement in a patient who has arthritis. Generation of wear particles in the artificial joint during action or movement is a serious issue and leads to aseptic loosening of joint. Research in the field of bio-tribology is trying to evaluate materials with minimum wear volume loss so as to extend joint life. Silicon nitride (Si3N4) is non-oxide ceramic suggested as a new alternative for hip/knee joint replacement. Hexagonal Boron Nitride (hBN) is recommended as a solid additive lubricant to improve the wear performance of Si3N4. In this paper, an attempt has been made to evaluate the optimum combination of load and % volume of hBN in Si3N4 to minimize wear volume loss (WVL). The experiments were conducted according to Design of Experiments (DoE)–Taguchi method and a mathematical model is developed. Further, this model is processed with Genetic Algorithm (GA) and Simulated Annealing (SA) to find out the optimum percentage of hBN in Si3N4 to minimize wear volume loss against Alumina (Al2O3) counterface. Taguchi method presents 15 N load and 8% volume of hBN to minimize WVL of Si3N4. While GA and SA optimization offer 11.08 N load, 12.115% volume of hBN and 11.0789 N load, 12.128% volume of hBN respectively to minimize WVL in Si3N4

Blend recognition from CAD mesh models using pattern matching

This paper reports a unique, platform-independent approach for blend recognition from CAD mesh model using pattern matching. About 60% of the average portion of the total facets in CAD mesh model is blended features. So, it becomes essential and necessary to extract these blend features for the successful accomplishment of seamless CAD/CAM integration. The facets of the same region have similar patterns. The focus of this paper is to recognize the blends using hybrid mesh segmentation based on pattern matching. Blend recognition has been carried out in three phases viz. preprocessing, pattern matching hybrid mesh segmentation and blend feature identification. In preprocessing, the adjacency relationship is set in facets of CAD mesh model, and then Artificial Neural Networks based threshold prediction is employed for hybrid mesh segmentation. In the second phase, pattern matching hybrid mesh segmentation is used for clustering the facets into patches based on distinct geometrical properties. After segmentation, each facet group is subjected to several conformal tests to identify the type of analytical surfaces such as a cylinder, cone, sphere, or tori. In the blend feature recognition phase, the rule-based reasoning is used for blend feature extraction. The proposed method has been implemented in VC++ and extensively tested on benchmark test cases for prismatic surfaces. The proposed algorithm extracts the features with coverage of more than 95 %. The innovation lies in “Facet Area” based pattern matching hybrid mesh segmentation and blend recognition rules. The extracted feature information can be utilized for downstream applications like tool path generation, computer-aided process planning, FEA, reverse engineering, and additive manufacturing

Systematics of pion emission in heavy ion collisions in the 1A GeV regime

Using the large acceptance apparatus FOPI, we study pion emission in the reactions (energies in GeV/nucleon are given in parentheses): 40Ca+40Ca (0.4, 0.6, 0.8, 1.0, 1.5, 1.93), 96Ru+96Ru (0.4, 1.0, 1.5), 96Zr+96Zr (0.4, 1.0, 1.5), 197Au+197Au (0.4, 0.6, 0.8, 1.0, 1.2, 1.5). The observables include longitudinal and transverse rapidity distributions and stopping, polar anisotropies, pion multiplicities, transverse momentum spectra, ratios for positively and negatively charged pions of average transverse momenta and of yields, directed flow, elliptic flow. The data are compared to earlier data where possible and to transport model simulations.Comment: 56 pages,42 figures; to be published in Nuclear Physics

Application of nanoparticles as additive for lubricant nano-materials in tribology

Background: Friction and wear are one of the major causes of failure of mechanism and machines in the field of Engineering. To overcome this problem, lubricants are provided in the engineering system. Lubricants are derived from synthetic hydrocarbon blends or mineral oils. Lubricants help to minimize friction and wear in contacting surface in order to reduce friction and minimize power loss. In certain situation, lubricants fail to satisfy their lubricating properties. In order to improve the attributes of lubricants, such as improving anti-oxidation capability, thermal properties, and tribological characteristic, a few additives can be added to the base oil. Objective: In the field of tribology, nanotechnology offers the opportunity for improving the performance of lubricant oil using nano-additives. The addition of nanoparticles to base oil will enhance the certain characteristic of lubricant oil, such as improving friction and wear resistance, improving load carrying capacity etc. This review presents the nano-additives in the field of lubricant industry. This review covers the various nano-additives and their application in the field of lubricant industry. Method: With a thorough review of literature in the field of tribology, nanotechnology and lubricants, various nano-additives and their advantages are discussed

Thermal analysis of surface grinding process by using design of experiments (Part-1)

Grinding in general is a very complex material removal operation involving cutting as well as ploughing and rubbing between the abrasive grains and the work material. The high temperatures are major source of thermal damage on the machined surface. It can lead to phase transformation in the materials being machined. It can also cause the workpiece burn, which is highly undesirable. In present work a simple moving heat source model has been developed to estimate maximum workpiece surface temperature during surface grinding process. The model is validated by using Design of Experiments (DoE) techniques by using Taguchi Orthogonal Arrays

CFD simulation of in cylinder combustion of multi-cylinder diesel engine

The simulation /reproduction of in cylinder combustion for power stroke of multicylinder Diesel Engine is appropriate/fundamental to work upon for determination of temperature inside the cylinder. The current examination incorporates estimating of approximate temperature of in chamber gases during power stroke and accordingly liner temperature from gas side. The current investigation incorporates mathematical simulations dependent on Inbuilt ICE Combustion model in ANSYS 15.0 form, where burning space above cylinder during power stroke which is time transient is utilized. Correct averaged boundary limits were determined for different sections for the ignition model. The mesh modular is created. The prevailing of different ranges of temperature recorded in literature during power stroke along with differential liner temperatures from gas side are surveyed. Estimations are done for maximum and minimum temperatures also. The maximum in cylinder temperature was around 2150 K and least temperature was discovered to be 800 K. Likewise the most extreme temperature on liner from gas side along stroke was discovered to be 470 K during power stroke. It has been additionally discovered that the greatest temperature of in chamber gases and liner from gas side endures just during early power stroke

Effect of lubricant viscosity and surface roughness on coefficient of friction in rolling contact

The main objective of this paper is to investigate the effect of surface roughness and lubricant viscosity on coefficient of friction in silicon nitride‐ steel rolling contact. Two samples of silicon nitride with two different values of surface roughness were tested against steel counter face. The test was performed on four ball tester in presence of lubricant with two different values of viscosity. Taguchi technique a methodology in design of experiment implemented to plan the experimentation and same is utilized to evaluate the interacting effect of surface roughness and lubricant viscosity. Analysis of experimental results presents a strong interaction between surface roughness and lubricant viscosity on coefficient of friction in rolling contact