First Steps to Virtual Mammography with the Surface Evolver

2015 ◽  
Vol 4 (2) ◽  
pp. 87-94
Author(s):  
M.Z. Nascimento ◽  
V. Ramos Batista
Keyword(s):  
Surface Evolver

Study on the Conversion Method of Three-Dimensional Shape Prediction Model of BGA Solder Joints

2013 ◽  
Vol 706-708 ◽  
pp. 1693-1696
Author(s):  
Hua Bin Zhao ◽  
De Jian Zhou
Keyword(s):  
Solder Joints ◽  
Three Dimensional ◽  
Ball Grid Array ◽  
Analysis Software ◽  
Surface Evolver ◽  
Element Analysis ◽  
Shape Prediction ◽  
Dimensional Shape ◽  
Point Line ◽  
Three Dimensional Shape

In the study of three-dimensional shape prediction of SMT solder joints, the software Surface Evolver has been widely applied as a quick and accurate effective tool for the prediction of solder joints shape. But the model it builds is not able to be directly imported into any finite element analysis software like ANSYS, and even after the import it still needs a lot of time to mend the import model. For this issue, to predict of the solder joints shape of ball grid array (BGA), the implement programs of three conversion methods of point-line-area method, axisymmetric method and infinitesimal method are given. By comparison, axisymmetric method and infinitesimal method are more suitable for the shape conversion of BGA solder joints.

Dynamic Aspects of Wetting Balance Tests

1996 ◽  
Vol 118 (3) ◽  
pp. 174-183 ◽  
Author(s):  
K. W. Moon ◽  
W. J. Boettinger ◽  
M. E. Williams ◽  
D. Josell ◽  
B. T. Murray ◽  
...  
Keyword(s):  
Software Package ◽  
Room Temperature ◽  
Silicone Oil ◽  
Surface Evolver ◽  
The Public ◽  
Meniscus Shape ◽  
Balance Tests ◽  
Glass Plates ◽  
Measured Force ◽  
Public Domain Software

The relationships between the force measured during wetting balance tests and the observed changes of contact angle and meniscus shape are studied. Experiments using silicone oil at 25, 50, and 100°C on glass plates as well as Pb-Sn eutectic solder on Au-coated glass plates are reported. Discrepancies between the measured force and height and those expected for a static meniscus are detailed. Equilibrium meniscus shapes are computed for wide plates using the elastica solution and for narrow plates using the public-domain software package, “Surface Evolver.” For room temperature experiments with oil, the measured force discrepancy disappears when the meniscus rise is complete. Thus, the force discrepancy may be due to shear stress exerted on the sample by fluid rising up the sample. For static menisci with heated liquids, force and meniscus height discrepancies do not disappear when the meniscus rise is complete. These discrepancies can be explained by Marangoni flow due to temperature gradients in the fluid for the oil experiments but not for the solder experiments.

Influence Of Solder Joint Shape On The Thermo-Mechanical Reliability Of CSP's

2004 ◽  
Vol 1 (2) ◽  
pp. 53-63 ◽  
Author(s):  
Co van Veen ◽  
Bart Vandevelde ◽  
Eric Beyne
Keyword(s):  
Solder Joint ◽  
Force Constant ◽  
Local Stress ◽  
Simulation Software ◽  
Temperature Cycling ◽  
Circuit Board ◽  
Surface Evolver ◽  
Joint Shape ◽  
Profile Estimation ◽  
Analytical Expressions

Not only the stand-off height but also the shape of a solder joint has a strong influence on the joint reliability under temperature cycling. The shape determines the size of the local stress and strain concentrations. It is therefore very important to know well the joint shape after reflow. In a previous paper closed analytical expressions were derived for liquid bump shapes, as a function of pad size and bump height [1]. The bump deformation as a function of the chip weight could be derived from the force constant. In the present paper closed analytical expressions are derived for the force constant for liquid bumps having unequal spherical pad sizes. It turns out that the force constant for compression can be optimized as a function of the ratio of those pad sizes. The shape of the bump and especially the contact angle is of interest for modeling activities where geometrical effects do play a role. Furthermore from the variation in bumps heights on a chip an estimate can be made of the tilt of the chip after assembly. The solder profile estimation by the analytical expressions is validated by experimental results. Also a comparison with the solder profile estimation by the simulation software Surface Evolver is done. Both comparisons showed that the analytical estimation of the standoff height is very good as long as the gravitation energy contributed by the chip weight is less than 10% of the total energy. Finally, an example is shown where the analytical model and Surface Evolver are the geometrical input for a finite element model. The example considers a CSP assembled at both sides of the printed circuit board.

Numerical Study on Film Foam Flow Characteristics in a Straight Duct

2013 ◽  
Vol 561 ◽  
pp. 472-477 ◽  
Author(s):  
Dong Xing Du ◽  
Fa Hu Zhang ◽  
Dian Cai Geng ◽  
Ying Ge Li
Keyword(s):  
Drag Force ◽  
Pressure Difference ◽  
Numerical Study ◽  
Flow Behavior ◽  
Petroleum Industry ◽  
Flow Characteristics ◽  
Viscous Force ◽  
Ideal Condition ◽  
Surface Evolver ◽  
The Mathematical Model

Straight ducts capture some essential features of the motion of foam in porous media in petroleum industry. In this paper, Surface Evolver was employed to build the mathematical model to study the flow behavior of lamellas in the duct with different models. Numerical results show good agreement with experiments and some important features of lamella flow behavior in straight ducts are obtained. It is concluded that, the physical model with viscous force can adequately describe the flow characteristics of reality foam in the experiment. The actual pressure difference consists of the pressure difference caused by the curvature of the lamellas and the drag force on the boundary wall. Under the ideal condition of without drag force along the wall, the pressure drop for lamella flow in the duct is zero, and the shape and the velocity of the lamellas will maintain constant.

New method for determining correction factors for pin-in-paste solder volumes

2017 ◽  
Vol 29 (1) ◽  
pp. 2-9 ◽  
Author(s):  
Oliver Krammer ◽  
Bertalan Varga ◽  
Karel Dušek
Keyword(s):  
Explicit Expression ◽  
Cross Sections ◽  
New Method ◽  
Solder Paste ◽  
Correction Factors ◽  
Surface Evolver ◽  
Volume Calculation ◽  
Content Type ◽  
The Common ◽  
Approach Zero

Purpose This paper aims to present a new method to calculate the appropriate volume of solder paste necessary for the pin-in-paste (PIP) technology. By the aid of this volume calculation, correction factors have been determined, which can be used to correct the solder fillet volume obtained by an explicit expression. Design/methodology/approach The method is based on calculating the optimal solder fillet shape and profile for through-hole (TH) components with given geometrical sizes. To calculate this optimal shape of the fillet, a script was written in Surface Evolver. The volume calculations were performed for different fillet radiuses (0.4-1.2 mm) and for different component lead geometries (circular and square cross-sections). Finally, the volume obtained by the Evolver calculations was divided by the volume obtained by an explicit expression, and correction factors were determined for the varying parameters. Findings The results showed that the explicit expression underestimates the fillet volume necessary for the PIP technology significantly (15-35 per cent). The correction factors for components with circular leads ranged between 1.4 and 1.59, whereas the correction factors for square leads ranged between 1.1 and 1.27. Applying this correction can aid in depositing the appropriate solder paste volume for TH components. Originality/value Determining the correct volume of solder paste necessary for the PIP technology is crucial to eliminate the common soldering failure of TH components (e.g. voiding or non-wetted solder pads). The explicit expression, which is widely used for volume calculation in this field, underestimates the necessary volume significantly. The new method can correct this estimation, and can aid the industry to approach zero-defect manufacturing in the PIP technology.

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