Grindability of Single Crystal Sapphire in Medical Use and the Scheme of Forming Highly Precise Spherical Heads

2011 ◽  
Vol 496 ◽  
pp. 13-18
Author(s):  
Otar Mgaloblishvili ◽  
Rauli Turmanidze ◽  
David Butskhrikidze ◽  
Mariam Beridze
Keyword(s):  
Surface Layer ◽  
Low Temperature ◽  
Single Crystal ◽  
Material Removal Rate ◽  
Material Removal ◽  
Removal Rate ◽  
Precision Grinding ◽  
Hip Joints ◽  
Grinding Conditions ◽  
Single Crystal Sapphire

The scale of influence of the single crystal sapphire crystallographic plane orientation and grinding conditions on the material removal rate, surface finish and the state of sub-surface layer have been studied under Low-Temperature Precision Grinding (LPG). The schemes of forming partial spherical heads for human hip joints endoprostheses are considered and elaborated. The possible versions of forming the spherical heads of endoprosthesis based on the novelties in kinematics and the mode of material removal are discussed.

Anisotropic Lapping of Single Crystal Sapphire

2010 ◽  
Vol 102-104 ◽  
pp. 502-505
Author(s):  
Ping Zhou ◽  
Peng Fei Gao ◽  
Wei Fang Wang ◽  
Dong Hui Wen
Keyword(s):  
Fracture Toughness ◽  
Surface Roughness ◽  
Elastic Modulus ◽  
Single Crystal ◽  
Material Removal Rate ◽  
Material Removal ◽  
Removal Rate ◽  
Surface Orientation ◽  
Experimental Results ◽  
Single Crystal Sapphire

Lapping processes of single crystal sapphire are investigated in relation to crystallo- graphic orientation, the influence of the crystal anisotropism under different lapping liquid concentration, loading forces on materials removal rate and roughness in sapphire lapping is discussed. C-plane(0001),M-plane ( ),R-plane ( ),A-plane ( ) sapphire wafers were used for lapping experiments, experimental results show that Surface roughness is depend on the fracture toughness, surface orientation with higher fracture toughness such as C-plane would get better roughness during lapping, material removal rate of R-plane is the lowest in four planes, it is for elastic modulus and fracture toughness of R-plane are less than other three planes.

scholarly journals Focused Ion Beam Milling of Single-Crystal Sapphire with A-, C-, and M-Orientations

Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2871
Author(s):  
Qiuling Wen ◽  
Xinyu Wei ◽  
Feng Jiang ◽  
Jing Lu ◽  
Xipeng Xu
Keyword(s):  
Single Crystal ◽  
Surface Quality ◽  
Material Removal ◽  
Focused Ion Beam ◽  
Removal Rate ◽  
Ion Beam ◽  
Crystal Orientations ◽  
Aluminum Ions ◽  
Single Crystal Sapphire

Sapphire substrates with different crystal orientations are widely used in optoelectronic applications. In this work, focused ion beam (FIB) milling of single-crystal sapphire with A-, C-, and M-orientations was performed. The material removal rate (MRR) and surface roughness (Sa) of sapphire with the three crystal orientations after FIB etching were derived. The experimental results show that: The MRR of A-plane sapphire is slightly higher than that of C-plane and M-plane sapphires; the Sa of A-plane sapphire after FIB treatment is the smallest among the three different crystal orientations. These results imply that A-plane sapphire allows easier material removal during FIB milling compared with C-plane and M-plane sapphires. Moreover, the surface quality of A-plane sapphire after FIB milling is better than that of C-plane and M-plane sapphires. The theoretical calculation results show that the removal energy of aluminum ions and oxygen ions per square nanometer on the outermost surface of A-plane sapphire is the smallest. This also implies that material is more easily removed from the surface of A-plane sapphire than the surface of C-plane and M-plane sapphires by FIB milling. In addition, it is also found that higher MRR leads to lower Sa and better surface quality of sapphire for FIB etching.

Modeling Material Removal Rate of Heavy Belt-Grinding in Manufacturing of U71Mn Material

2016 ◽  
Vol 693 ◽  
pp. 1082-1089 ◽  
Author(s):  
Rong Quan Wang ◽  
Jian Yong Li ◽  
Yue Ming Liu ◽  
Wen Xi Wang
Keyword(s):  
Material Removal Rate ◽  
Material Removal ◽  
High Efficiency ◽  
Removal Rate ◽  
Low Cost ◽  
Belt Grinding ◽  
Abrasive Particles ◽  
Grinding Conditions ◽  
Modeling Material ◽  
Abrasive Cutting

The heavy belt-grinding is a new machining method, which combined the characters of heavy-duty grinding and belt-grinding together, with high efficiency and low cost. In the present paper the removal rate model of heavy belt-grinding in manufacturing of U71Mn steel is established. It is assumed that the distribution of the abrasive particles protrusion height of the abrasive belt surface closes to Gaussian distribution. The model is presented by calculating the removal volumes of all abrasive grains contributing to cutting action based on the probability theory, elastic-plastic mechanics and abrasive cutting theory. It is analysis that the material removal rate depends essentially on the mechanical properties of the workpiece and the belt and the grinding conditions. It is proportional to the average pressure, belt velocity and the indentation depth and is inverse proportion to the grain size.

Effect of Polishing Time and Pressure on Polishing Pad Performance

2008 ◽  
Vol 389-390 ◽  
pp. 510-514
Author(s):  
A.Q. Biddut ◽  
Liang Chi Zhang ◽  
Y.M. Ali
Keyword(s):  
Single Crystal ◽  
Material Removal Rate ◽  
Material Removal ◽  
Removal Rate ◽  
Single Crystal Silicon ◽  
Crystal Silicon ◽  
Critical Limit ◽  
Polishing Pads ◽  
Required Quality ◽  
Effective Life

This paper experimentally investigates the effect of time and pressure on the condition of polishing pads and the material removal rate (MRR) of single crystal silicon. It was found that as the pad deteriorates with time, MRR decreases. Surfaces with a required quality can only be achieved before the texture deterioration reaches a critical limit. At a higher pressure, 25 kPa, deterioration is slower, and the effective life of pads and MRR is enhanced.

An Experimental Study on Grinding Fir-Tree Root Forms Using Vitrified CBN Wheels

2014 ◽  
Vol 1017 ◽  
pp. 55-60 ◽  
Author(s):  
Zhong De Shi ◽  
Amr Elfizy ◽  
Helmi Attia
Keyword(s):  
Experimental Study ◽  
Material Removal Rate ◽  
Material Removal ◽  
Removal Rate ◽  
Turbine Blades ◽  
Wheel Wear ◽  
Part Quality ◽  
Grinding Conditions ◽  
Vitrified Cbn ◽  
Maximum Material Removal Rate

An experimental study was undertaken to explore the conditions and performance on rough and finish grinding fir-tree root forms of turbine blades made of a nickel-based alloy using vitrified CBN wheels and water-based grinding fluid. This work was motivated by switching the grinding of fir-tree root forms from grinding with conventional abrasive wheels to vitrified CBN wheels for reducing overall production cost and enhancing productivity. Grinding experiments were conducted to measure grinding forces, power, surface roughness, and stress near the blade roots under various dressing and grinding conditions. Wheel re-dressing life in terms of the total number of good parts ground between dressing was tested with the condition producing the maximum material removal rate while satisfying preset part quality and process requirements. It was found that the maximum material removal rate achievable in rough grinding was restricted by the stress limit and the wheel re-dressing life was dominated by the radial wheel wear limit. The targeting part quality and process requirements were achieved. It was proved that vitrified CBN grinding process is feasible and very promising to machine fir-tree root forms.

Effect of Abrasives on the Lapping Performance of 6H-SiC Single Crystal Wafer

2013 ◽  
Vol 690-693 ◽  
pp. 2179-2184 ◽  
Author(s):  
Wei Li ◽  
Qiu Sheng Yan ◽  
Jia Bin Lu ◽  
Ji Sheng Pan
Keyword(s):  
Surface Roughness ◽  
Grain Size ◽  
Single Crystal ◽  
Material Removal Rate ◽  
Material Removal ◽  
High Efficiency ◽  
Removal Rate ◽  
Lower Surface ◽  
Crystal Wafer ◽  
Sic Wafer

In order to remove the cutting marks on the cutting surface of 6H-SiC single crystal wafer, experiments were conducted to investigate the effect of the abrasive characteristics (types, grain size, concentration and mixed abrasives) on the lapping performance of 6H-SiC single crystal wafer, then the removal mechanism of the abrasive grains in the lapping process was studied. Results indicate that the abrasives with larger grain size and higher hardness can result in a higher material removal rate while the abrasives with smaller grain size and lower hardness can achieve a lower surface roughness value. When the concentration of the abrasives is 7.69 wt%, a good lapping effect was obtained. Lower surface roughness value Ra can be obtained with a high material removal rate by using certain proportion mixed abrasives. Selecting appropriate abrasives can obtain a high surface quality of 6H-SiC wafer with a high efficiency.

scholarly journals Investigation on the Material Removal and Surface Generation of a Single Crystal SiC Wafer by Ultrasonic Chemical Mechanical Polishing Combined with Ultrasonic Lapping

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2022 ◽  
Author(s):  
Yong Hu ◽  
Dong Shi ◽  
Ye Hu ◽  
Hongwei Zhao ◽  
Xingdong Sun
Keyword(s):  
Surface Roughness ◽  
Single Crystal ◽  
Material Removal Rate ◽  
Chemical Mechanical Polishing ◽  
Material Removal ◽  
Removal Rate ◽  
Surface Generation ◽  
Ultrasonic Assisted ◽  
Single Crystal Sic ◽  
Sic Wafer

A new method of ultrasonic chemical mechanical polishing (CMP) combined with ultrasonic lapping is introduced to improve the machining performance of carbide silicon (SiC). To fulfill the method, an ultrasonic assisted machining apparatus is designed and manufactured. Comparative experiments with and without ultrasonic assisted vibration are conducted. According to the experimental results, the material removal rate (MRR) and surface generation are investigated. The results show that both ultrasonic lapping and ultrasonic CMP can decrease the two-body abrasion and reduce the peak-to-valley (PV) value of surface roughness, the effect of ultrasonic in lapping can contribute to the higher MRR and better surface quality for the following CMP. The ultrasonic assisted vibration in CMP can promote the chemical reaction, increase the MRR and improve the surface quality. The combined ultrasonic CMP with ultrasonic lapping achieved the highest MRR of 1.057 μm/h and lowest PV value of 0.474 μm. Therefore this sequent ultrasonic assisted processing method can be used to improve the material removal rate and surface roughness for the single crystal SiC wafer.

Sign in / Sign up

Export Citation Format

Share Document