AN EMPIRICAL MODEL OF LOW PLASTICITY BURNISHING TO IMPROVE SURFACE ROUGHNESS AND HARDNESS

Wire electrical discharge machining is a machining method by which parts having various contours could be detached from plate workpieces. The method uses the electrical discharges developed between the workpiece and the wire tool electrode found in an axial motion, when in the work zone a dielectric fluid is recirculated. In order to highlight the influence exerted by some input process factors on the surface roughness parameter Ra in case of a workpiece made of an alloyed steel, a factorial experiment with six independent variables at two variation levels was designed and materialized. As input factors, one used the workpiece thickness, pulse on time, pulse off-time, wire axial tensile force, current intensity average amplitude defined by setting button position and travelling wire electrode speed. By mathematical processing of the experimental results, empirical models were established. Om the base of a power type empirical model, graphical representations aiming to highlight the influence of some input factors on the surface roughness parameter Ra were achieved. The power type empirical model facilitated establishing of order of factors able to exert influence on the surface roughness parameter Ra at wire electrical discharge machining.

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INVESTIGATION OF SINGLE-POINT DRESSING OVERLAP RATIO AND DIAMOND-ROLL DRESSING INTERFERENCE ANGLE ON SURFACE ROUGHNESS IN GRINDING

Transactions of the Canadian Society for Mechanical Engineering ◽

10.1139/tcsme-2010-0018 ◽

2010 ◽

Vol 34 (2) ◽

pp. 295-308 ◽

Cited By ~ 12

Author(s):

Akram Saad ◽

Robert Bauer ◽

Andrew Warkentin

Keyword(s):

Surface Roughness ◽

Material Removal Rate ◽

Empirical Model ◽

Material Removal ◽

Removal Rate ◽

Single Point ◽

Experimental Conditions ◽

Workpiece Surface ◽

Different Depths ◽

Overlap Ratio

This paper investigates the effect of both single-point and diamond-roll dressing techniques on the workpiece surface roughness in grinding. Two empirical surface roughness models are studied – one that incorporates single-point dressing parameters, and another that incorporates diamond-roll dressing parameters. For the experimental conditions used in this research, the corresponding empirical model coefficients are found to have a linear relationship with the inverse of the overlap ratio for single-point dressing and the interference angle for diamond-roll dressing. The resulting workpiece surface roughness models are then experimentally validated for different depths of cut, workpiece speeds and dressing conditions. In addition, the models are used to derive a relationship between overlap ratio for single-point dressing, and interference angle for diamond-roll dressing such that both dressing techniques produce a similar surface finish for a given material removal rate.

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Surface Integrity of Biodegradable Magnesium-Calcium (Mg-Ca) Alloy by Low Plasticity Burnishing

STLE/ASME 2010 International Joint Tribology Conference ◽

10.1115/ijtc2010-41214 ◽

2010 ◽

Author(s):

M. Salahshoor ◽

Y. B. Guo

Keyword(s):

Surface Roughness ◽

Residual Stresses ◽

Surface Integrity ◽

Bulk Material ◽

Large Diameter ◽

Biological Response ◽

The Body ◽

Low Plasticity Burnishing ◽

Sever Plastic Deformation ◽

Biodegradable Magnesium

When a device is implanted into the body, into either hard or soft tissue, the body will respond. While the bulk material of the device is often important for integrity and mechanical success, the device surface is at the interface with biology. Major effort has been spent modifying a biomaterial surface in order to elicit or inhibit a biological response. Metallic biodegradable Magnesium-Calcium (Mg-Ca) alloys have attracted an increased attention for orthopedic fixation applications. This research focuses on low plasticity burnishing (LPB) as a novel surface modification technique that is added to the surface to control biodegradation as a biological response. The effects of burnishing pressure as an important process parameter on surface integrity characteristics such as surface roughness, surface topography, and residual stresses are investigated. Burnished surface roughness is smaller than the machined ones. However, some amount of waviness is observed which might be due to large diameter of the burnishing ball and sever plastic deformation. High compressive residual stresses are measured on the burnished surface.

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Model of surface roughness and material removal using abrasive flow machining of selective laser melted channels

Rapid Prototyping Journal ◽

10.1108/rpj-09-2019-0241 ◽

2020 ◽

Vol 26 (7) ◽

pp. 1165-1176

Author(s):

Julian Ferchow ◽

Harry Baumgartner ◽

Christoph Klahn ◽

Mirko Meboldt

Keyword(s):

Surface Roughness ◽

Empirical Model ◽

Material Removal ◽

Maximum Deviation ◽

Channel Diameter ◽

Content Type ◽

Abrasive Flow Machining ◽

Fluid Behavior ◽

Proposed Model ◽

Power Law Index

Purpose Internal channels produced by selective laser melting (SLM) have rough surfaces that require post-processing. The purpose of this paper is to develop an empirical model for predicting the material removal and surface roughness (SR) of SLM-manufactured channels owing to abrasive flow machining (AFM). Design/methodology/approach A rheological model was developed to simulate the viscosity and power-law index of an AFM medium. To simulate the pressure distribution and velocity in the SLM channels, the fluid behavior and SR in the channels were simulated by using computational fluid dynamics. The results of this simulation were then applied to create an empirical model that can be used to predict the SR and material removal thickness. To verify this empirical model, it was applied to an actual part fabricated by SLM. The results were compared with the measurements of the SR and channel diameter subsequent to AFM. Findings The proposed model exhibits maximum deviation between the model and the measurement of −1.1% for the down-skin SR, −0.2% for the up-skin SR and −0.1% for material removal thickness. Practical implications The results of this study show that the proposed model can avoid expensive iterative tests to determine whether a given channel design leads to the desired SR after smoothing by AFM. Therefore, this model helps to design an AFM-ready channel geometry. Originality/value In this paper, a quantitatively validated AFM model was proposed for complex SLM channels with varying orientation angles.

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A semi-empirical model for electron mobility at the SiC/SiO2 interface

MRS Proceedings ◽

10.1557/proc-742-k4.8 ◽

2002 ◽

Vol 742 ◽

Cited By ~ 5

Author(s):

Nelson S. Saks

Keyword(s):

Surface Roughness ◽

Empirical Model ◽

Gate Voltage ◽

Mobility Model ◽

Coulomb Scattering ◽

Mos Devices ◽

Surface Roughness Scattering ◽

Hall Effect Measurements ◽

Semi Empirical ◽

Mos Device

ABSTRACTThe mobility of electrons in inversion layers at SiC/SiO2 interfaces μinv has been characterized in 4H- and 6H-SiC using Hall effect measurements. In order to understand the cause of the low mobilities typically observed in SiC MOS devices, a semi-empirical mobility model has been developed based on a previous model for silicon inversion layers. Using this model, two scattering mechanisms, surface phonon and Coulomb scattering from high densities of electrons trapped at the SiC/SiO2 interface, are found to account reasonably well for the behavior of the mobility. The model employs a changing density of trapped electrons as a function of gate voltage to accurately model Coulomb scattering. Surprisingly, evidence of surface roughness scattering is not observed in any SiC MOS device.

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Study on Precision Polishing of a Mini Roller Mold

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.126-128.551 ◽

2010 ◽

Vol 126-128 ◽

pp. 551-556

Author(s):

Choung Lii Chao ◽

Ying Ching Hsiao ◽

Wen Chen Chou ◽

Chia Wei Kuo ◽

Wen Lang Lai ◽

...

Keyword(s):

Surface Roughness ◽

Material Removal Rate ◽

Surface Finish ◽

Empirical Model ◽

Material Removal ◽

Removal Rate ◽

Surface Condition ◽

Microscopic Analysis ◽

Semi Empirical ◽

Better Than

This research aimed to design and develop a polishing system for precision polishing mini roller mold to nanometer surface finish. An experimental polishing system was built in the present study to polish nickel plated specimens with various polishing compounds. The polished specimens were subsequently examined by Alfa-step, OM and SEM for surface finish, morphology and microscopic analysis respectively. The obtained surface condition and material removal rate were correlated to the polishing parameters such as spindle speed, abrasive concentration, and abrasive grit size for the improvement of the polishing effect. Mini-rollers of 5mm in diameter, 50mm in length were successfully polished to a surface roughness better than 2nm Ra in several hours without damaging the roundness and cylindricalness using abrasive of 0.3μm, 10,000rpm polishing speed and 0.5mm gap distance between polisher and the specimen. A semi-empirical model of polishing was also developed in the study for predicting the materials removal rate.

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Calibrated Integral Equation Model for Bare Soil Moisture Retrieval of Synthetic Aperture Radar: A Case Study in Linze County

Applied Sciences ◽

10.3390/app10217921 ◽

2020 ◽

Vol 10 (21) ◽

pp. 7921

Author(s):

Ling Zhang ◽

Hao Li ◽

Zhaohui Xue

Keyword(s):

Integral Equation ◽

Surface Roughness ◽

Soil Moisture ◽

Synthetic Aperture Radar ◽

Correlation Length ◽

Empirical Model ◽

Incidence Angle ◽

Bare Soil ◽

Equation Model ◽

Synthetic Aperture

Soil moisture plays a significant role in surface energy balance and material exchange. Synthetic aperture radar (SAR) provides a promising data source to monitor soil moisture. However, soil surface roughness is a key difficulty in bare soil moisture retrieval. To reduce the measurement error of the correlation length and improve the inversion accuracy, we used the surface roughness (Hrms, root mean surface height) and empirical correlation length lopt as proposed by Baghdadi to introduce analytical equations of the backscattering coefficient using the calibrated integral equation model (CIEM). This empirical model was developed based on analytical equations to invert soil moisture for Hrms between 0.5 and 4 cm. Experimental results demonstrated that when the incidence angle varied from 33.5° to 26.3°, R2 of the retrieved and measured soil moisture decreased from 0.67 to 0.57, and RMSE increased from 2.53% to 5.4%. Similarly, when the incidence angle varied from 33.5° to 26.3°, R2 of the retrieved and measured Hrms decreased from 0.64 to 0.51, and RMSE increased from 0.33 to 0.4 cm. Therefore, it is feasible to use the empirical model to invert soil moisture and surface roughness for bare soils. In the inversion of the soil moisture and Hrms, using Hrms and the empirical correlation length lopt as the roughness parameters in the simulations is sufficient. The empirical model has favorable validity when the incidence angle is set to 33.5° and 26.3° at the C-band.

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Surface Roughness Model for Worn Inserts of Face Milling: Part II — An Empirical Model

Tribology Transactions ◽

10.1080/10402000108982438 ◽

2001 ◽

Vol 44 (1) ◽

pp. 142-146 ◽

Cited By ~ 3

Author(s):

Gary C. Barber ◽

Randy Gu ◽

Qinyu Jiang ◽

Jie Gu ◽

Simon Tung

Keyword(s):

Surface Roughness ◽

Empirical Model ◽

Face Milling ◽

Roughness Model

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Research on Machined Surface Quality for High Speed Turning Titanium Alloy Membrane Discs and Optimization of Cutting Parameters

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.33.246 ◽

2010 ◽

Vol 33 ◽

pp. 246-250

Author(s):

Wei Zhang ◽

Min Li Zheng ◽

Ming Ming Cheng ◽

Wen Yong Shi

Keyword(s):

Surface Roughness ◽

Titanium Alloy ◽

Empirical Model ◽

High Speed ◽

Cutting Parameters ◽

Machined Surface ◽

Cutting Parameter ◽

High Speed Turning ◽

Machined Surface Roughness ◽

Cutting Parameter Optimization

By high speed turning experiment of aerospace engine titanium alloy membrane discs, it researches cutting parameters influence on machined surface roughness of titanium alloy membrane discs, meanwhile measures and analyzes machined surface topography. Machined surface roughness multi-linear regression empirical model of high speed end-surface turning titanium alloy membrane discs is established. Using cutting parameter combination obtained from cutting parameter optimization makes process verification experiment of high speed turning titanium alloy membrane discs. The results show that the established machined surface roughness empirical model of high speed turning titanium alloy membrane discs is credible in statistics, and the process verifying experiment effect is good by using optimized cutting parameters.

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