Micro Pattern Forming of Spiral Grooves in a Fluid Dynamic Bearing Using Desktop Forming System

2012 ◽  
Vol 538-541 ◽  
pp. 1203-1207 ◽  
Author(s):  
Jung Han Song ◽  
Jeanho Park ◽  
Jong Sup Lee ◽  
Seo Gou Choi ◽  
Hye Jin Lee ◽  
...  
Keyword(s):  
Fluid Dynamic ◽  
Dynamic Pressure ◽  
Disk Drive ◽  
Spiral Groove ◽  
Micro Forming ◽  
Forming Process ◽  
Micro Pattern ◽  
Fluid Dynamic Bearing ◽  
Pattern Forming ◽  
Groove Pattern

This research explores the micro-forming process of spiral groove pattern on Fluid Dynamic Bearing(FDB), which is utilized in precision driving part of the hard disk drive(HDD), using micro desktop forming system. While EDM and ECM process has been widely used to engrave the precision pattern which generates dynamic pressure on FDBs, micro forming process is newly proposed in this study to increase the productivity and to reduce the product costs. At first, desktop forming system is designed for spiral groove pattern forming. FE simulations are followed in order to evaluate the feasibility of micro-forming. The simulation results show that forming loads of 1,500Kgf is required to fabricate micro patterns with the depth of 15 μm. Finally the formability test is carried out with various forming loads. Deformed shapes and forming loads obtained from the test are compared with those from the analysis. The results fully demonstrate that micro pattern forming techniques are available to fabricate micro spiral groove patterns in FDB.

Multi-Stage Deep Drawing Process of Thin Sheets for the Sleeve Housing Component of a Spindle Motor in HDD

2013 ◽  
Vol 389 ◽  
pp. 359-363 ◽  
Author(s):  
S.M. Yeon ◽  
S. Choi ◽  
G.A. Lee ◽  
S.J. Park ◽  
J.H. Kim ◽  
...  
Keyword(s):  
Fluid Dynamic ◽  
Thin Sheet ◽  
Disk Drive ◽  
Spindle Motor ◽  
Low Noise ◽  
Drawing Process ◽  
Forming Process ◽  
Multi Stage ◽  
Metal Forming Process ◽  
Housing Component

High-precision micro-fluid dynamic bearing is the key part in a hard disk drive, as it offers low noise levels, high speeds and high rates of accuracy with low amount of vibration. To enhance the performance, a thin sheet component called sleeve housing are newly adopted in FDB. In this paper, multi-stage sheet metal forming process is utilized to fabricate the sleeve housing component. Multi-stage drawing simulations are conducted to investigate the adequate process parameters preventing wrinkling and tearing. From the simulation result, multi-stage drawing processes are conducted with progressive die sets in order to evaluate the forming accuracy. The results reveal that it is successful to fabricate the sleeve housing component with multi-stage drawing process.

Control of Machining Profiles Based on Material Removal Capabilities in Cylindrical Blasting

2016 ◽  
Vol 1136 ◽  
pp. 125-130
Author(s):  
Masashi Harada ◽  
Kazuhito Ohashi ◽  
Taketo Fukushima ◽  
Shinya Tsukamoto
Keyword(s):  
Chemical Etching ◽  
Material Removal ◽  
Fluid Dynamic ◽  
Dynamic Pressure ◽  
Electrochemical Machining ◽  
Disk Drive ◽  
Groove Depth ◽  
High Accuracy ◽  
Processing Unit ◽  
Central Processing

Fluid dynamic bearings, which have an advantage in high-accuracy revolutions, are employed for spindle motors of hard disk drive, cooling fans for central processing unit, spindles of machine tool, etc. Micro herring-bone grooves are manufactured on cylindrical surface of the shafts in the bearing units, and they generate dynamic pressure during spins. Although the depth of the herring-bone grooves is generally constant, the shafts of which groove depth decreases from the ends of the groove array to its center improve the performance of bearing. The micro grooves are mainly manufactured by chemical etching, electrochemical machining, cutting and form rolling. However, the chemical etching and the electrochemical machining are difficult to control 3D machining profiles with high accuracy. The cutting and the form rolling have problems in tool lives and manufacturing costs. On the other hand, blasting is expected as one of micro fabrication methods. Therefore, we focused on blasting, and have investigated its material removal capabilities by fundamental tests. The purpose of this study is to control machining profiles in cylindrical blasting. The machining profiles of cylindrical workpieces in blasting were simulated based on the material removal capabilities obtained by the fundamental blasting tests. Then, the simulated profiles agreed well with the experimental ones by blasting under the same experimental condition.

Fluid dynamic bearing for HD-DVD single-phase spindle motor

2003 ◽  
Author(s):  
Hung-Kuang Hsu ◽  
Chien-Chang Wang ◽  
Mei-Lin Lai ◽  
Yu-Hsiu Chang ◽  
Der-Ray Huang
Keyword(s):  
Single Phase ◽  
Fluid Dynamic ◽  
Spindle Motor ◽  
Fluid Dynamic Bearing

Modeling of Flow Fields of Different Delivery Chamfers in Spray Forming Process

2014 ◽  
Vol 789 ◽  
pp. 554-559
Author(s):  
Yang Liu ◽  
Zhou Li ◽  
Guo Qing Zhang ◽  
Wen Yong Xu
Keyword(s):  
Flow Field ◽  
Gas Flow ◽  
Fluid Dynamic ◽  
Metal Flow ◽  
Spray Forming ◽  
Operating Pressure ◽  
Delivery Tube ◽  
Forming Process ◽  
Atomization Process ◽  
Sharp Point

The computational fluid dynamic (CFD) software was used to calculate the velocity field in atomization chamber of spray forming equipment. The relationship between melt flow rates, gas aspiration of the atomizer and operating pressure are complex, and the above mentioned parameters are closely related to the atomization process. The influences of different delivery chamfers on gas flow field, which is determined by atomizer structure, were analyzed. Using K-epsilon model with a symmetrical domain, the gas dynamic of different delivery chamfer conditions were investigated. The results indicate that the sharp point of delivery tube causes detachment of flow field, and 56°, 45° and 34° chamfer conditions have same diffusion angle. Gas was aspirated from delivery tube when chamfer was 0°, which is beneficial to liquid metal flow in atomization process.

Dieless Water Jet Incremental Micro-Forming

2018 ◽  
Author(s):  
Yi Shi ◽  
Jian Cao ◽  
Kornel F. Ehmann
Keyword(s):  
Process Parameters ◽  
Thin Shell ◽  
High Speed ◽  
Single Point ◽  
Sheet Thickness ◽  
Water Jet ◽  
Micro Forming ◽  
Forming Process ◽  
Thin Foils ◽  
High Pressure Water Jet

Compared to the conventional single-point incremental forming (SPIF) processes, water jet incremental micro-forming (WJIMF) utilizes a high-speed and high-pressure water jet as a tool instead of a rigid round-tipped tool to fabricate thin shell micro objects. Thin foils were incrementally formed with micro-scale water jets on a specially designed testbed. In this paper, the effects on the water jet incremental micro-forming process with respect to several key process parameters, including water jet pressure, relative water jet diameter, sheet thickness, and feed rate, were experimentally studied using stainless steel foils. Experimental results indicate that feature geometry, especially depth, can be controlled by adjusting the processes parameters. The presented results and conclusions provide a foundation for future modeling work and the selection of process parameters to achieve high quality thin shell micro products.

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