A Study on Surface Quality of GaN with CMP Polishing Process

2011 ◽  
Vol 291-294 ◽  
pp. 1764-1767
Author(s):  
Wei Li ◽  
Ming Ming Ma ◽  
Bin Hu
Keyword(s):  
Surface Roughness ◽  
Particle Size ◽  
Gallium Nitride ◽  
Surface Quality ◽  
Chemical Reaction ◽  
Experimental Result ◽  
Precision Machining ◽  
Polishing Process

This paper introduced a polishing process for planarization of gallium nitride (GaN) wafer by polishing slurry that is made up by the chemical reaction with H2O2 solution and iron. Some different polishing parameters in the polishing process has been analyzed, which affect the surface quality of wafers, such as slurry particle size, polishing times, polishing slurry etc., and trying to improve the polishing process by optimization of the polishing parameters. The experimental result showed that this polishing method has an effect on the surface quality of GaN wafers, finally, the efficient and precision machining with surface roughness of GaN wafers of Ra0.81 nm has been gained by the CMP polishing process.

Super Polishing Behaviour Investigation of Stainless Steel Optical Lens Moulding Inserts

2009 ◽  
Vol 404 ◽  
pp. 97-102
Author(s):  
Kui Liu ◽  
S.T. Ng ◽  
K.C. Shaw ◽  
G.C. Lim
Keyword(s):  
Surface Roughness ◽  
Stainless Steel ◽  
Surface Quality ◽  
Optical Quality ◽  
Polishing Process ◽  
Optical Lens ◽  
Fine Diamond ◽  
Diamond Paste ◽  
Quality Surface

Super polishing experiments were carried out to investigate the effects of polishing parameters on surface quality of stainless steel lens moulding inserts, and to optimize polishing conditions. Experimental results indicated that optical quality surface of stainless steel lens moulding inserts can be achieved through a two-step polishing process: fast polishing with a soft wood head and coarse diamond paste, and fine polishing with a nylon-covered steel ball head and fine diamond paste. A diameter of 20 mm stainless steel lens moulding insert with a surface roughness Ra of 7.6 nm has been successfully achieved using the two-step super polishing process.

Observation in the Surface Roughness of Silicon Wafer during Semi-Fixed Abrasive Machining with Large Grains

2009 ◽  
Vol 69-70 ◽  
pp. 253-257
Author(s):  
Ping Zhao ◽  
Jia Jie Chen ◽  
Fan Yang ◽  
K.F. Tang ◽  
Ju Long Yuan ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Surface Quality ◽  
Silicon Wafer ◽  
Processing Parameters ◽  
Wafer Surface ◽  
Abrasive Machining ◽  
Fixed Abrasive ◽  
Is Failure ◽  
Better Than

Semi-fixed abrasive is a novel abrasive. It has a ‘trap’ effect on the hard large grains that can prevent defect effectively on the surface of the workpiece which is caused by large grains. In this paper, some relevant experiments towards silicon wafers are carried out under the different processing parameters on the semi-fixed abrasive plates, and 180# SiC is used as large grains. The processed workpieces’ surface roughness Rv are measured. The experimental results show that the surface quality of wafer will be worse because of higher load and faster rotating velocity. And it can make a conclusion that the higher proportion of bond of the plate, the weaker of the ‘trap’ effect it has. Furthermore the wet environment is better than dry for the wafer surface in machining. The practice shows that the ‘trap’ effect is failure when the workpiece is machined by abrasive plate which is 4.5wt% proportion of bond in dry lapping.

The mechanism of process parameters influencing the AlSi10Mg side surface quality fabricated via laser powder bed fusion

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Shimin Dai ◽  
Hailong Liao ◽  
Haihong Zhu ◽  
Xiaoyan Zeng
Keyword(s):  
Surface Roughness ◽  
Surface Quality ◽  
Process Parameters ◽  
Laser Power ◽  
Side Surface ◽  
Laser Powder Bed Fusion ◽  
Scanning Velocity ◽  
Content Type ◽  
Powder Bed

Purpose For the laser powder bed fusion (L-PBF) technology, the side surface quality is essentially important for industrial applicated parts, such as the inner flow parts. Contour is generally adopted at the parts’ outline to enhance the side surface quality. However, the side surface roughness (Ra) is still larger than 10 microns even with contour in previous studies. The purpose of this paper is to study the influence of contour process parameters, laser power and scanning velocity on the side surface quality of the AlSi10Mg sample. Design/methodology/approach Using L-PBF technology to manufacture AlSi10Mg samples under different contour process parameters, use a laser confocal microscope to capture the surface information of the samples, and obtain the surface roughness Ra and the maximum surface height Rz of each sample after analysis and processing. Findings The results show that the side surface roughness decreases with the increase of the laser power at the fixed scanning velocity of 1,000 mm/s, the side surface roughness Ra stays within the error range as the contour velocity increases. It is found that the Ra increases with the scanning velocity increasing and the greater the laser power with the greater Ra increases when the laser power of contour process parameters is 300 W, 350 W and 400 W. The Rz maintain growth with the contour scanning velocity increasing at constant laser power. The continuous uniform contour covers the pores in the molten pool of the sample edge and thus increase the density of the sample. Two mechanisms named “Active adhesion” and “Passive adhesion” cause sticky powder. Originality/value Formation of a uniform and even contour track is key to obtain the good side surface quality. The side surface quality is determined by the uniformity and stability of the contour track when the layer thickness is fixed. These research results can provide helpful guidance to improve the surface quality of L-PBF manufactured parts.

SURFACE ROUGHNESS OF MAGNESIUM ALLOY AZ91D IN HIGH SPEED MILLING

2016 ◽  
Vol 78 (6-9) ◽  
Author(s):  
Mohd Shahfizal Ruslan ◽  
Kamal Othman ◽  
Jaharah A.Ghani ◽  
Mohd Shahir Kassim ◽  
Che Hassan Che Haron
Keyword(s):  
Surface Roughness ◽  
Magnesium Alloy ◽  
Feed Rate ◽  
High Speed ◽  
Cutting Parameters ◽  
Experimental Result ◽  
Depth Of Cut ◽  
Polishing Process ◽  
High Speed Cutting ◽  
Radial Depth

Magnesium alloy is a material with a high strength to weight ratio and is suitable for various applications such as in automotive, aerospace, electronics, industrial, biomedical and sports. Most end products require a mirror-like finish, therefore, this paper will present how a mirror-like finishing can be achieved using a high speed face milling that is equivalent to the manual polishing process. The high speed cutting regime for magnesium alloy was studied at the range of 900-1400 m/min, and the feed rate for finishing at 0.03-0.09 mm/tooth. The surface roughness found for this range of cutting parameters were between 0.061-0.133 µm, which is less than the 0.5µm that can be obtained by manual polishing. Furthermore, from the S/N ratio plots, the optimum cutting condition for the surface roughness can be achieved at a cutting speed of 1100 m/min, feed rate 0.03 mm/tooth, axial depth of cut of 0.20 mm and radial depth of cut of 10 mm. From the experimental result the lowest surface roughness of 0.061µm was obtained at 900 m/min with the same conditions for other cutting parameters. This study revealed that by milling AZ91D at a high speed cutting, it is possible to eliminate the polishing process to achieve a mirror-like finishing.

Experimental Investigation of Strengthening and Polishing Aeroengine Blades

2011 ◽  
Vol 101-102 ◽  
pp. 909-912
Author(s):  
Guo Ying Zeng ◽  
Deng Feng Zhao
Keyword(s):  
Surface Roughness ◽  
Experimental Investigation ◽  
Fatigue Strength ◽  
Surface Quality ◽  
Three Dimensional ◽  
Experimental Results ◽  
Technological Parameters ◽  
Polishing Process ◽  
Optimum Parameters ◽  
The Media

The three-dimensional vibratory strengthening and polishing technology was used to strengthen and polish aeroengine blades with complicated surfaces. At first, the principle of the strengthening and polishing process was introduced, which combined strengthening process with polishing process. Then, the technological parameters influenced on the surface quality were investigated. The principal variables were the media hardness, the frequency and amplitude of the vibration, and duration of the vibratory strengthening and polishing. The optimum parameters were obtained. Experimental results revealed that, after strengthening and polishing, the surface roughness of aeroengine blades was reduced from Ra0.35-0.5μm to Ra0.1-0.12μm, and fatigue strength was increased by approximately 50%.

Investigation of the Effects of Technological Parameters on Surface Roughness in Extrusion Bars of Aluminum Alloy

2019 ◽  
Vol 889 ◽  
pp. 155-160
Author(s):  
Trong Mai Nguyen ◽  
Đuc Quy Tran ◽  
Van Nghe Pham ◽  
Van Canh Nguyen
Keyword(s):  
Surface Roughness ◽  
Aluminum Alloy ◽  
Surface Quality ◽  
Research Work ◽  
Extrusion Process ◽  
Optimal Parameters ◽  
Technological Parameters

In this research work, the result of the effects of technological parameters on surface roughness in extrusion bars of aluminum alloy were pesented. The results of this study may be used for choosing optimal parameters of extrusion process so that surface quality of extruded bar was improved.

scholarly journals Impact of Structural Defects on the Surface Quality of Hardwood Species Sliced Veneers

2020 ◽  
Vol 10 (18) ◽  
pp. 6265
Author(s):  
Vasiliki Kamperidou ◽  
Efstratios Aidinidis ◽  
Ioannis Barboutis
Keyword(s):  
Surface Roughness ◽  
Surface Quality ◽  
Wood Species ◽  
Research Work ◽  
Structural Defects ◽  
Material Surface ◽  
Typical Structure ◽  
Hardwood Species ◽  
The Impact

The surface roughness constitutes one of the most critical properties of wood and wood veneers for their extended utilization, affecting the bonding ability of the veneers with one another in the manufacturing of wood composites, the finishing, coating and preservation processes, and the appearance and texture of the material surface. In this research work, logs of five significant European hardwood species (oak, chestnut, ash, poplar, cherry) of Balkan origin were sliced into decorative veneers. Their surface roughness was examined by applying a stylus tracing method, on typical wood structure areas of each wood species, as well as around the areas of wood defects (knots, decay, annual rings irregularities, etc.), to compare them and assess the impact of the defects on the surface quality of veneers. The chestnut veneers presented the smoothest surfaces, while ash veneers, despite the higher density, recorded the highest roughness. In most of the cases, the roughness was found to be significantly lower around the defects, compared to the typical structure surfaces, probably due to lower porosity, higher density and the presence of tensile wood. The results reveal that the presence of defects does not affect the roughness of the veneers and increases neither the processing requirements of the veneer sheets before finishing, nor the respective production cost of veneers and the veneer-based wood panels. The high utilization prospects of the examined wood species in veneer production, even those bearing various defects, is highlighted.

scholarly journals Surface Roughness Investigation of Poly-Jet 3D Printing

Mathematics ◽  
2020 ◽  
Vol 8 (10) ◽  
pp. 1758
Author(s):  
Nectarios Vidakis ◽  
Markos Petousis ◽  
Nikolaos Vaxevanidis ◽  
John Kechagias
Keyword(s):  
Surface Roughness ◽  
3D Printing ◽  
Surface Quality ◽  
Back Propagation ◽  
Physical Models ◽  
Layer By Layer ◽  
Linear Regression Models ◽  
Feed Forward Back Propagation ◽  
The Impact

An experimental investigation of the surface quality of the Poly-Jet 3D printing (PJ-3DP) process is presented. PJ-3DP is an additive manufacturing process, which uses jetted photopolymer droplets, which are immediately cured with ultraviolet lamps, to build physical models, layer-by-layer. This method is fast and accurate due to the mechanism it uses for the deposition of layers as well as the 16 microns of layer thickness used. Τo characterize the surface quality of PJ-3DP printed parts, an experiment was designed and the results were analyzed to identify the impact of the deposition angle and blade mechanism motion onto the surface roughness. First, linear regression models were extracted for the prediction of surface quality parameters, such as the average surface roughness (Ra) and the total height of the profile (Rt) in the X and Y directions. Then, a Feed Forward Back Propagation Neural Network (FFBP-NN) was proposed for increasing the prediction performance of the surface roughness parameters Ra and Rt. These two models were compared with the reported ones in the literature; it was revealed that both performed better, leading to more accurate surface roughness predictions, whilst the NN model resulted in the best predictions, in particular for the Ra parameter.

scholarly journals Steel mould surface improvement by robot fluid jet polishing and robot pad polishing for polymer optic production

2019 ◽  
Vol 215 ◽  
pp. 05003
Author(s):  
Rui Almeida ◽  
Timon Ebert ◽  
Rainer Börret ◽  
Mario Pohl
Keyword(s):  
Surface Roughness ◽  
Material Removal ◽  
Geometrical Shape ◽  
Polishing Process ◽  
Shape Deviation ◽  
Mould Surface ◽  
Shape Correction ◽  
Steel Mould ◽  
Surface Improvement

In order to improve the quality of injection-moulded polymer optic parts, it is necessary to improve the quality of the respective steel moulds. For this reason, it is not only necessary to improve the surface roughness of the mould, but also its geometrical shape. The material removal obtained from robot pad polishing is too low. This makes a shape correction after the milling step a very prolonged process. The aim of this work is to use a polishing chain to improve the surface quality of steel samples in terms of shape deviation and surface roughness. This correction polishing chain uses the robot fluid jet polishing for the geometrical shape correction and afterwards the robot pad polishing for the improvement of the surface roughness. Due to the high material removal rates of the fluid jet polishing, it is possible to correct the geometrical shape of steel moulds very fast up to a certain deviation. The pad polishing process improves the surface roughness of the steel samples. A correction of the shape deviation of more than 80% with a RMS of approximately 8 nm was obtained.

Characterization of Cutting-Induced Heat Generation in Ultra-Precision Milling of Aluminium Alloy 6061

2013 ◽  
Vol 552 ◽  
pp. 201-206
Author(s):  
Su Juan Wang ◽  
Suet To ◽  
Xin Du Chen
Keyword(s):  
Surface Roughness ◽  
Surface Quality ◽  
Heat Generation ◽  
Feed Rate ◽  
Dimensional Accuracy ◽  
Precision Machining ◽  
Machined Surface ◽  
Single Crystal Diamond ◽  
Ultra Precision ◽  
Alloy 6061

The technology of ultra-precision machining with single crystal diamond tool produces advanced components with higher dimensional accuracy and better surface quality. The cutting-induced heat results in high temperature and stress at the chip-tool and tool-workpiece interfaces therefore affects the materials and the cutting tool as well as the surface quality. In the ultra-precision machining of al6061, the cutting-induced heat generates precipitates on the machined surface and those precipitates induce imperfections on the machined surface. This paper uses the time-temperature-precipitation characteristics of aluminum alloy 6061 (al6061) to investigate the effect of feed rate on the cutting-induced heat generation in ultra-precision multi-axis milling process. The effect of feed rate and feed direction on the generation of precipitates and surface roughness in ultra-precision raster milling (UPRM) is studied. Experimental results show that heat generation in horizontal cutting is less than that in vertical cutting and a larger feed rate generates more heat on the machined workpiece. A smaller feed rate produces a better surface finish and under a larger feed rate, scratch marks are produced by the generated precipitates and increase surface roughness.

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