scholarly journals Manufacture of Hemispherical Shell and Surrounding Eave-Shaped Electrodes

Micromachines ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 815
Author(s):  
Renxin Wang ◽  
Bing Bai ◽  
Wendong Zhang ◽  
Huiliang Cao ◽  
Jun Liu
Keyword(s):  
Surface Roughness ◽  
Quality Factor ◽  
Shell Thickness ◽  
Estimation Method ◽  
Fabrication Process ◽  
Electrical Insulation ◽  
Hemispherical Shell ◽  
Hemispherical Resonator ◽  
The Asymmetry

A hemispherical resonator consists of a hemispherical shell and the surrounding circular electrodes. The asymmetry of a hemispherical shell has influence on the vibrating mode and quality factor. The gap distance from shell to electrode is critical for the capacitance and sensitivity of a hemispherical resonator. To realize a symmetric shell and a small gap, a kind of micro-hemispherical resonator (μHR) structure including sandwich-shaped stacks and eave-shaped electrodes has been developed using a glassblowing process. The blowing process could bring favorable surface roughness and symmetry. The locations of the hemispherical shell and surrounding electrodes can be precisely controlled by the designs of sandwich-shaped stacks and eave-shaped electrodes, making it feasible to realize uniform and small gaps. In addition, electrical insulation between the hemispherical shell and eave-shaped electrodes can be guaranteed owing to eave-shaped structure. The fabrication process and results are demonstrated in detail. Furthermore, an estimation method of shell thickness in a nondestructive manner is proposed, with deviation below 5%. Taking asymmetry, surface roughness, and gap into consideration, these results preliminarily indicate this structure with a hemispherical shell and surrounding eave-shaped electrodes is promising in hemispherical resonator applications.

Differential Ceramic Shell Thickness Evaluation for Direct Rapid Investment Casting

2013 ◽  
Vol 315 ◽  
pp. 418-422 ◽  
Author(s):  
M.F.M. Omar ◽  
S. Sharif ◽  
Mustaffa Ibrahim ◽  
Mohd Hasbullah Idris ◽  
A.S.A. Fadzil ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Investment Casting ◽  
High Speed ◽  
Shell Thickness ◽  
Direct Method ◽  
Low Cost ◽  
Acrylonitrile Butadiene Styrene ◽  
Rp Process ◽  
Shell Mould ◽  
Crack Defect

Rapid prototyping (RP) process offers a promising economical way as a sacrificial pattern in investment casting (IC) at high speed and low cost for low volume part manufacturing. However direct sacrificial RP pattern have encountered shell cracking during burnout process due to polymer based materials. Shell mould thickness was need to be concerned to have strong enough to withstand RP part expansion for employing direct method. The aim of present research was to compare the efficacy of different shell thickness for aluminum casting part fabricated from acrylonitrile butadiene styrene (ABS) and acrylate based material made from FDM and MJM respectively. The hollow RP pattern has been used directly to produce ceramic moulds. The feasibility of ceramic mould has been assessed in term of burnout ability and crack defect. Dimensional accuracies and surface roughness of the castings part have been observed in this investigation. Result shows thicker mould with proposed stuco procedure resulted without any crack defect for botRP part and no residual ash remained when firing higher than 870°C of temperature.In addition, FDM produced better accuracy for overall mould thickness, but MJM have better surface roughness. Therefore both direct RP pattern were suitable to be used in IC process with proposed shell thickness.

Effect of Geometric Imperfections on Anchor Loss and Characterisation of a Gyroscope Resonator with High Quality Factor

2020 ◽  
Vol 28 (3) ◽  
pp. 18-31
Author(s):  
G.N. Sharma ◽  
◽  
Sundararajan T. ◽  
G.S. Singh ◽  
◽  
...  
Keyword(s):  
Quality Factor ◽  
Shell Thickness ◽  
Sensitivity Study ◽  
Thickness Variation ◽  
Q Factor ◽  
Surface Characterisation ◽  
Geometric Imperfections ◽  
Before And After ◽  
Functional Part ◽  
Anchor Loss

A critical functional part of a hemispherical resonator gyroscope (HRG) is the mechanical resonator, and a few million quality factor (Q-factor) is needed for the lowest resolution. This paper focuses on anchor loss of a HRG of a few millimeters in size. A detailed parametric study of dimensions and shell imperfections due to fabrication is carried out. A sensitivity study of the effect of shell mean radius, shell thickness, stem radius, stem height on the Qanchor is carried out. The effect of geometric imperfections such as shell offset, shell tilt, shell thickness variation, and unbalance is studied in detail. From the study, it is inferred that the anchor loss becomes very significant and approaches other loss mechanisms even with minor geometric imperfections in the hardware realisation. Based on the sensitivity study, the dimensional and geometric tolerances are arrived for precision fabrication. Precision resonator is fabricated as per the requirement of minimum anchor loss. The significance of other damping mechanisms such as air damping, excitationinduced damping, thermoelastic dynamic damping and surface dissipation is also discussed. Surface characterisation before and after surface treatment has been carried out using nanoindentation technique with regard to surface loss. Functional parameters of operating frequency and Q-factor are evaluated using laser Doppler vibrometry (LDV).

Study on Surface Roughness Transformation during Metal Rolling

2012 ◽  
Vol 706-709 ◽  
pp. 2517-2522
Author(s):  
Saud Almotairy ◽  
Dong Bin Wei ◽  
Zheng Yi Jiang
Keyword(s):  
Surface Roughness ◽  
Quality Factor ◽  
Processing Parameters ◽  
Experimental Results ◽  
Thin Strip ◽  
Manufacturing Processes ◽  
Strip Surface ◽  
New Findings ◽  
Cold Rolled

Increasing the demand for cold rolled ultra thin strip as feedstock for miniaturized products has encouraged researchers to investigate the ways to increase the quality of such products, especially those related to strip surface roughness. Surface is known as quality factor in most of manufacturing processes. In this paper, the effect of the rolling parameters on the surface roughness transformation during metal rolling has been studied. The experimental results demonstrate that the surface roughness transformation during the metal rolling is highly affected by the designation of the processing parameters such as finishing temperature, reduction, rolling passes and lubrication. The results have been discussed to verify the validity of the new findings.

Study on Surface Roughness Transformation during Metal Rolling

2011 ◽  
Vol 418-420 ◽  
pp. 897-902
Author(s):  
Saud Almotairy ◽  
Dong Bin Wei ◽  
Zheng Yi Jiang
Keyword(s):  
Surface Roughness ◽  
Quality Factor ◽  
Processing Parameters ◽  
Experimental Results ◽  
Thin Strip ◽  
Manufacturing Processes ◽  
Strip Surface ◽  
New Findings ◽  
Cold Rolled

Increasing the demand for cold rolled ultra thin strip as feedstock for miniaturized products has encouraged researchers to investigate the ways to increase the quality of such products, especially those related to strip surface roughness. Surface is known as quality factor in most of manufacturing processes. In this paper, the effect of the rolling parameters on the surface roughness transformation during metal rolling has been studied. The experimental results demonstrate that the surface roughness transformation during metal rolling is highly affected by the designation of the processing parameters such as finishing temperature, reduction, rolling passes and lubrication. The results have been discussed to verify the validity of the new findings.

Build-up electrical insulation material with low-dielectric tangent, low-CTE and low-surface roughness

2010 ◽  
Author(s):  
Isao Suzuki ◽  
Toshiaki Tanaka ◽  
Akihiro Uenishi ◽  
Takayuki Kobayashi ◽  
Junnosuke Murakami
Keyword(s):  
Surface Roughness ◽  
Electrical Insulation ◽  
Insulation Material ◽  
Low Dielectric
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