The Case Study on Model Reconstruction Method for Inner Un-Measurable Parts

2009 ◽  
Vol 16-19 ◽  
pp. 847-850
Author(s):  
Bi Hong Lu ◽  
Xiao Fang Zheng

Reverse Engineering (RE), as the important technology for learning and mastering the advanced technology, as well as shortening the period of product design and development, has already become the highlight in the manufacturing industry. But there are some inner un-measurable parts, like couplers. The inner form information of the coupler can not be fully captured without any cutting, which is one of the bottlenecks in RE. Therefore, an effective method needs to be explored for reconstructing lumen model. Taking model reconstruction of coupler lumen as a case, an assembly reverse method is proposed by analyzing the parts functions and restraint relations in coupler. The method in detail is that, firstly, all parts are assembled in the coupler body lumen, then, according to assembly relations and the enveloping space determined by movement scope of individual parts, the coupler lumen shape can be obtained. The method proposed is successfully applied in model reconstruction of heavy haul coupler, and which provides a common solution of model reconstruction for inner un-measurable parts.

Author(s):  
Zhigang Song ◽  
Jochonia Nxumalo ◽  
Manuel Villalobos ◽  
Sweta Pendyala

Abstract Pin leakage continues to be on the list of top yield detractors for microelectronics devices. It is simply manifested as elevated current with one pin or several pins during pin continuity test. Although many techniques are capable to globally localize the fault of pin leakage, root cause analysis and identification for it are still very challenging with today’s advanced failure analysis tools and techniques. It is because pin leakage can be caused by any type of defect, at any layer in the device and at any process step. This paper presents a case study to demonstrate how to combine multiple techniques to accurately identify the root cause of a pin leakage issue for a device manufactured using advanced technology node. The root cause was identified as under-etch issue during P+ implantation hard mask opening for ESD protection diode, causing P+ implantation missing, which was responsible for the nearly ohmic type pin leakage.


2018 ◽  
Vol 74 (6) ◽  
Author(s):  
Chandrashekhar K. Patil ◽  
M. Husain ◽  
N.V. Halegowda

Author(s):  
Baohai Wu ◽  
Hai Zheng ◽  
Ying Zhang ◽  
Ming Luo ◽  
Dinghua Zhang

Author(s):  
Alessandro Bianchini ◽  
Francesco Balduzzi ◽  
Giovanni Ferrara ◽  
Lorenzo Ferrari

The assessment of robust CFD techniques is casting new light on the aerodynamics of airfoils rotating around an axis orthogonal to flow direction, with particular reference to flow curvature effects and stall mechanisms. In particular, Darrieus wind turbines’ designers are taking profit from these new discovers to improve the aerodynamic design of the rotors, in view of an increase of the overall efficiency and a reduction of the structural stresses on the blades. A controversial design parameter for Darrieus turbines, especially in case of small-size rotors, is represented by the location of the blade-spoke connection along the chord. The most common solution is indeed to place the connection at approximately airfoil’s quarter chord, i.e. where the pressure center is commonly located for low incidence angles. In some cases, however, the blade is connected at middle chord due to symmetry or aesthetic reasons. In some small turbines, innovative designs have even disregarded this parameter. Even if one can argue that the blade connection point is about to have some aerodynamic effects on the turbine’s performance, the real impact of this important design parameter is often not fully understood. The present study makes use of extensive CFD simulations on a literature case study, using a NACA 0021 airfoil, to assess the influence of the blade-spoke connection point. In particular, the differences in terms of power coefficient curve of the turbine, optimal tip-speed ratio, torque profiles and stresses on the connection are analyzed and discussed. Detailed flow analyses are also shown for azimuthal positions of particular interest. Results on the selected case study showed that the middle-chord blade-spoke connection point seems to guarantee a higher performance of the rotor, even if additional solicitation is applied to the connection itself. It is further shown that the same performance can indeed be obtained with the airfoil attached at quarter chord and properly pitched. By doing so, the stresses are contained and the performance is maximized.


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