scholarly journals Model for Predicting the Micro-Grinding Force of K9 Glass Based on Material Removal Mechanisms

Micromachines ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 969
Author(s):  
Hisham Manea ◽  
Xiang Cheng ◽  
Siying Ling ◽  
Guangming Zheng ◽  
Yang Li ◽  
...  
Keyword(s):  
Optical Glass ◽  
High Surface ◽  
Chip Thickness ◽  
High Hardness ◽  
Industrial Applications ◽  
Grinding Force ◽  
Machining Accuracy ◽  
Force Model ◽  
Tool Diameter ◽  
K9 Glass

K9 optical glass has superb material properties used for various industrial applications. However, the high hardness and low fracture toughness greatly fluctuate the cutting force generated during the grinding process, which are the main factors affecting machining accuracy and surface integrity. With a view to further understand the grinding mechanism of K9 glass and improve the machining quality, a new arithmetical force model and parameter optimization for grinding the K9 glass are introduced in this study. Originally, the grinding force components and the grinding path were analyzed according to the critical depth of plowing, rubbing, and brittle tear. Thereafter, the arithmetical model of grinding force was established based on the geometrical model of a single abrasive grain, taking into account the random distribution of grinding grains, and this fact was considered when establishing the number of active grains participating in cutting Nd-Tot. It should be noted that the tool diameter changed with machining, therefore this change was taking into account when building the arithmetical force model during processing as well as the variable value of the maximum chip thickness amax accordingly. Besides, the force analysis recommends how to control the processing parameters to achieve high surface and subsurface quality. Finally, the force model was evaluated by comparing theoretical results with experimental ones. The experimental values of surface grinding forces are in good conformity with the predicted results with changes in the grinding parameters, which proves that the mathematical model is reliable.

Design and Testing of a Micro-Dynamometer for Desktop Micro-Milling Machine

2014 ◽  
Vol 902 ◽  
pp. 267-273 ◽  
Author(s):  
Samir Mekid
Keyword(s):  
Surface Finish ◽  
Cutting Forces ◽  
High Speed ◽  
High Surface ◽  
Chip Thickness ◽  
Micro Milling ◽  
High Tech ◽  
Machining Accuracy ◽  
Microscopic Features ◽  
Better Than

The emerging miniaturized high-tech products are required to have increased functionalities of systems within a volumetric size on the order of 1 cm3. Hence, the parts are mesoscopic with complex microscopic features of a few mm length with machining accuracy of better than 1 micrometer with secured surface integrity as components will require high surface finish, tensile stress and crack free surfaces in order to function reliably. One of the characteristics to be measured is the cutting forces on the parts being machined. This paper will present the design, manufacture and testing of a miniature dynamometer capable of measuring cutting forces within a low range of 50N but with a resolution better than 1 mN and high frequency since the micromachining involves small cutting forces but the spindle rotates at high speed. The dynamometer is capable of measuring forces in five directions (±x, ±y, and z). The instrument was calibrated and exhibit very good results leading to a true validation. This instrument is assembled on a micro milling desktop machine designed in-house. It will not only support predicting the surface finish and chip thickness but also monitoring tool wear evolution and hence prevents/reduce tool breakage known to be one of the main issues in micro-milling.

Experimental study on force model in grinding of maraging steel 3J33

2018 ◽  
Vol 233 (10) ◽  
pp. 3475-3486
Author(s):  
Weicheng Guo ◽  
Beizhi Li ◽  
Shouguo Shen ◽  
Qinzhi Zhou
Keyword(s):  
Maraging Steel ◽  
Chip Thickness ◽  
Rayleigh Distribution ◽  
Grinding Force ◽  
Machining Process ◽  
Hertzian Contact ◽  
Force Model ◽  
Three Stages ◽  
Force Components ◽  
Validation Tests

Grinding is always a complicated machining process for joint interaction of numerous random abrasive grits in different chip formation processes. Therefore, analysis of grinding force requires a more comprehensive insight on the grinding mechanisms. This paper is devoted to propose an analytical force model in grinding of maraging steel 3J33 based on the fact that grinding process is divided into three stages, namely rubbing, ploughing and cutting, in terms of grits working status. These three stages are determined by the chip thickness model that is assumed to conform to Rayleigh distribution, in which the rubbing stage is derived from Hertzian contact theory. The experimental coefficients in the force model are calibrated by performing a set of training tests. The predicted normal and tangential grinding forces of the developed model are compared with those obtained from validation tests, which show favorable agreement quantitatively. The contributions of the grinding force components in different grit–workpiece interaction stages are obtained from the model and theirs relationships with process parameters are discussed.

Surface Grinding Force Model of Steel 55 Based on Undeformed Chip Thickness with CBN Electroplated Wheels

2011 ◽  
Vol 189-193 ◽  
pp. 1768-1773 ◽  
Author(s):  
Jun Ming Wang ◽  
Ren Zhen Ye ◽  
Hui Peng Chen ◽  
Hong Zan Bin
Keyword(s):  
Velocity Ratio ◽  
Influence Factors ◽  
Chip Thickness ◽  
Grinding Force ◽  
Calculation Model ◽  
Surface Grinding ◽  
Force Model ◽  
Undeformed Chip Thickness ◽  
Abrasive Grains ◽  
Random Direction

Undeformed chip thickness is one of the most important parameters in grinding process, which is related to the entire abrasive grains in grinding simultaneously and changed periodically with time. Simplifying the geometric shape of abrasive grains ,the paper modifies the mathematic models of undeformed chip thickness by analytic method, establishes an universal calculation model of grinding force based on undeformed chip thickness, then optimizes the parameters of the model by restrictive random direction method according to the measuring experiments of the inter-grain spacing about CBN electroplated wheels and the grinding experiments of steel 55 during surface grinding, analyses the influence factors of the friction ratio on the grinding force. The results show that under the same grinding depth， both of the ratio and the grinding force will be decreased with the increase of velocity ratio VS/VW, but the ratio increases and the grinding force decreases with the increase of inter-grain spacing.

Basic Study on Ductile-Mode Grinding of Optical Glass Lenses with Rubber Bonded Diamond Wheels

2016 ◽  
Vol 874 ◽  
pp. 241-246
Author(s):  
Yuya Kawana ◽  
Rei Sekiguchi ◽  
Yuta Mizumoto ◽  
Yasuhiro Kakinuma ◽  
Katsutoshi Tanaka ◽  
...  
Keyword(s):  
Optical Glass ◽  
High Surface ◽  
Chip Thickness ◽  
Precision Grinding ◽  
Basic Study ◽  
High Surface Quality ◽  
Large Aperture ◽  
Single Lens ◽  
Ductile Mode ◽  
Ultra Precision

Large aperture lenses with high surface quality are demanded for professional imaging products such as single-lens reflex cameras and astronomical telescopes. Large aperture optical lenses are shaped by ultra-precision grinding and finished by prolonged polishing. However, the prolonged polishing process leads to deterioration of the form accuracy. In order to reduce the amount of polishing, ductile-mode ultra-precision grinding is demanded. In this study, a rubber bonded wheel, which has a low elastic modulus, is used for grinding of spherical glass BK7, and influence of the hardness of the rubber bonded wheel and abrasive chip thickness on brittle fracture and surface roughness are experimentally investigated.

A Time Domain Dynamic Simulation Model for Stability Prediction of Infeed Centerless Grinding Processes

2006 ◽  
Vol 129 (3) ◽  
pp. 539-550 ◽  
Author(s):  
Hongqi Li ◽  
Yung C. Shin
Keyword(s):  
Chip Thickness ◽  
Grinding Force ◽  
Grinding Wheel ◽  
Force Model ◽  
Deformation Model ◽  
Two Dimensional ◽  
New Model ◽  
Grinding Processes ◽  
Centerless Grinding ◽  
Surface Profiles

This paper presents a comprehensive dynamic model that simulates infeed centerless grinding processes and predicts their instability-related characteristics. The new model has the unique ability of accurately predicting the coupled chatter and lobing process of a multi-degree of freedom and two-dimensional centerless grinding system by considering its critical issues. First, the model considers the complete two-dimensional kinematics, dynamics, surface profiles, and the geometrical interactions of the workpiece with the grinding wheel, regulating wheel, and supporting blade. Second, a two-dimensional distributed grinding force model along the contact length is adopted and modified for centerless grinding processes as a function of normalized uncut chip thickness. The forces of the work holding system are determined by balancing the grinding force and accordingly the work holding instability can be identified as well. Third, a two-dimensional contact deformation model under the condition of general surface profiles or pressure distributions is developed for the contacts of the workpiece with the grinding wheel, regulating wheel, and supporting blade. The new model is validated by comparing the predicted chatter and lobing occurrences with experimental results.

scholarly journals Coal Fly Ash Derived Silica Nanomaterial for MMMs—Application in CO2/CH4 Separation

Membranes ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 78
Author(s):  
Marius Gheorghe Miricioiu ◽  
Violeta-Carolina Niculescu ◽  
Constantin Filote ◽  
Maria Simona Raboaca ◽  
Gheorghe Nechifor
Keyword(s):  
Fly Ash ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Coal Fly Ash ◽  
High Surface ◽  
Industrial Applications ◽  
Mixed Matrix Membranes ◽  
Co2 Removal ◽  
Mcm 41

In order to obtained high selective membrane for industrial applications (such as natural gas purification), mixed matrix membranes (MMMs) were developed based on polysulfone as matrix and MCM-41-type silica material (obtained from coal fly ash) as filler. As a consequence, various quantities of filler were used to determine the membranes efficiency on CO2/CH4 separation. The coal fly ash derived silica nanomaterial and the membranes were characterized in terms of thermal stability, homogeneity, and pore size distribution. There were observed similar properties of the obtained nanomaterial with a typical MCM-41 (obtained from commercial silicates), such as high surface area and pore size distribution. The permeability tests highlighted that the synthesized membranes can be applicable for CO2 removal from CH4, due to unnoticeable differences between real and ideal selectivity. Additionally, the membranes showed high resistance to CO2 plasticization, due to permeability decrease even at high feed pressure, up to 16 bar.

Grinding Force Model for Low-Speed Grinding Based on Impact Principle

2013 ◽  
Vol 797 ◽  
pp. 123-128
Author(s):  
Ming He Liu ◽  
Xiu Ming Zhang ◽  
Shi Chao Xiu
Keyword(s):  
Sliding Friction ◽  
Impact Load ◽  
Grinding Force ◽  
Calculation Model ◽  
Force Model ◽  
Grinding Process ◽  
Low Speed ◽  
Impact Area ◽  
Force Mechanism ◽  
The Impact

In the low-speed grinding process, the force generated when the wheel grinding the workpiece is the result of sliding friction, plough and cutting. While in the actual study, the cutting process has attracted extensive attention. Impact effect to the entire grinding process on the contact is ignored so that the error exists between the calculation grinding force and the measured grinding force. Basing on the shock effect to the grinding process, the paper divides the contact area into impact area and cutting area. And the model of impact load generated from single grit is built. Moreover, the grinding force theoretical calculation model and total grinding force mathematical model is also constructed by analyzing the impact load affecting on the grinding force mechanism. Finally experimental study verifies the correctness of theoretical analysis.

scholarly journals Morphological and Elemental Investigations on Co–Fe–B–O Thin Films Deposited by Pulsed Laser Deposition for Alkaline Water Oxidation: Charge Exchange Efficiency as the Prevailing Factor in Comparison with the Adsorption Process

2021 ◽  
Author(s):  
Y. Popat ◽  
M. Orlandi ◽  
S. Gupta ◽  
N. Bazzanella ◽  
S. Pillai ◽  
...  
Keyword(s):  
Pulsed Laser Deposition ◽  
Water Oxidation ◽  
Active Sites ◽  
High Surface ◽  
Pulsed Laser ◽  
Industrial Applications ◽  
Active Species ◽  
Laser Deposition ◽  
Core Shell ◽  
Adsorption Sites

Abstract Mixed transition-metals oxide electrocatalysts have shown huge potential for electrochemical water oxidation due to their earth abundance, low cost and excellent electrocatalytic activity. Here we present Co–Fe–B–O coatings as oxygen evolution catalyst synthesized by Pulsed Laser Deposition (PLD) which provided flexibility to investigate the effect of morphology and structural transformation on the catalytic activity. As an unusual behaviour, nanomorphology of 3D-urchin-like particles assembled with crystallized CoFe2O4 nanowires, acquiring high surface area, displayed inferior performance as compared to core–shell particles with partially crystalline shell containing boron. The best electrochemical activity towards water oxidation in alkaline medium with an overpotential of 315 mV at 10 mA/cm2 along with a Tafel slope of 31.5 mV/dec was recorded with core–shell particle morphology. Systematic comparison with control samples highlighted the role of all the elements, with Co being the active element, boron prevents the complete oxidation of Co to form Co3+ active species (CoOOH), while Fe assists in reducing Co3+ to Co2+ so that these species are regenerated in the successive cycles. Thorough observation of results also indicates that the activity of the active sites play a dominating role in determining the performance of the electrocatalyst over the number of adsorption sites. The synthesized Co–Fe–B–O coatings displayed good stability and recyclability thereby showcasing potential for industrial applications. Graphic Abstract

Increasing Hardness of Surface Layer of Low-Carbon Steel by Account of Plasma Treatment of Coating Modification

2021 ◽  
Vol 316 ◽  
pp. 794-802
Author(s):  
Andrey E. Balanovsky ◽  
Van Trieu Nguyen
Keyword(s):  
Surface Layer ◽  
Thermal Treatment ◽  
Plasma Treatment ◽  
Plasma Heating ◽  
High Surface ◽  
Surface Hardness ◽  
High Hardness ◽  
Diffusion Region ◽  
Low Carbon ◽  
Wide Range

The Purpose of paper is to conduct studies to assess the possibility of increasing the hardness of the surface layer of steel St3 grade by plasma heating of the applied surface coating containing powder alloy PR-N80X13S2R. Mixtures of pasta were divided into 2 groups: for furnace chemical-thermal treatment and plasma surface melting. The study of the microstructure showed a difference in the depth of the saturated layer, depending on the processing method, during chemical-thermal treatment-1 mm, plasma fusion - 2 mm. The results of measuring the surface micro-hardness showed that, the obtained coating from a mixture of PR-N80X13S2R + Cr2O3 + NH4Cl has a uniform high surface hardness (31-64 HRC), from a mixture of only PR-N80X13S2R - the surface hardness varies in a wide range (15-60 HRC). The study of the microhardness of the cross section of the surface layer showed that, the diffusion region: from a mixture of powder PR-N80X13S2R + Cr2O3 + NH4Cl has uniform hardness (450-490 HV); from a mixture of PR-N80X13S2R - hardness increases in the depth of the molten region (from 300 to 600 HV), and sharply decreases in the heat affected zone (210-170 HV). The use of PR-N80X13S2R alloy powder as the main component in the composition of the paste deposited on the St3 surface during plasma treatment leads to the formation of a doped surface layer with high hardness.

Corrosion and Wear Protection through Micro Arc Oxidation Coatings in Aluminum and Its Alloys

2019 ◽  
Author(s):  
L. Rama Krishna ◽  
G. Sundararajan
Keyword(s):  
Corrosion Resistance ◽  
Surface Properties ◽  
High Hardness ◽  
Basic Mechanism ◽  
Industrial Applications ◽  
Corrosion Properties ◽  
Micro Arc Oxidation ◽  
Coating Formation ◽  
Wear And Corrosion Resistance ◽  
Technological Limitations

This article presents the brief overview of fairly recent and eco-friendly micro arc oxidation (MAO) coating technology. The weight-cost-performance benefits in general raised the interest to utilize lightweight materials, especially the aluminum and its alloys. Despite numerous engineering advantages, the aluminum alloys themselves do not possess suitable tribology and corrosion resistance. Therefore, improvements in surface properties are essential to enable developing potential industrial applications. For improving wear and corrosion resistance of Al alloys, the most demanding surface properties are high hardness and chemical inertness. The technical and technological limitations associated with traditional anodizing and hard anodizing processes have been the strongest driving force behind the development of new MAO technology. While presenting the key technological elements associated with the MAO process, the basic mechanism of coating formation and its phase gradient nature is presented. Influence of various process parameters including the electrolyte composition has been discussed. The typical microstructural features and distribution of α- and γ-Al2O3 phases across the coating thickness as a key strategy to form dense coatings with required mechanical, tribological, and corrosion properties which are vital to meet potential application demands are briefly illustrated.

Sign in / Sign up

Export Citation Format

Share Document