Home / Examples / Fluid Analysis [Bernoulli] / Example 17: Solder Wicking Analysis

Example 17: Solder Wicking Analysis

  

General

• The shape of the solder bridging the terminal and copper foil is analyzed using the VOF method.
   

• The volume fractions of soler and air each are solved.
   

• Unless specified in the list below, the default conditions are applied.
  

• 2D and 3D analysis models are provided.
  

• Simulation Time (2D): around 16 minutes
  Simulation Time (3D): around 32 minutes

 

• Obtain this session's project file. (Right-click and choose 'Save link as')




• Results will vary depending on Femtet version and the PC environment.

 

Analysis Space

Item	Settings
Analysis Space	2D
Model Unit	mm

Analysis Conditions

Item	Tab	Settings
Solver	Solver Selection	Fluid Analysis [Bernoulli]
Analysis Type	Fluid Analysis	Transient Analysis
Free Surface Analysis (VOF Method)	Fluid Analysis	Free Surface Analysis (VOF Method): Select
Free Surface Analysis (VOF Method) Setting	Fluid Analysis	Phase Setting: Register [000_Air] and [LiquidSolder]   The material [LiquidSolder] needs to be registered beforehand. (See [ How to Create New Material Property] for more information)   Take into account weight: Select Take into account surface tension: Select Phase Pair Setting: Phase 1 Phase 2 Surface Tension Contact Angle 000_Air LiquidSolder 0.349 60
Setup Details	Fluid Analysis Setup Details	Volume Control Type: Cell-centered Base
Timestep	Transient Analysis	Setting Item Settings Timestep Specified by 100 [us] Number of Calculation Steps 400 Output Interval 10
Meshing Setup (2D Analysis)	Mesh	Setting Item Settings     General Mesh Size Specified by 0.1 [mm] Element Type Rectangular-Free/Sweep Mesh
Meshing Setup (3D Analysis)	Mesh	Setting Item Settings     General Mesh Size: Specified by 0.4 [mm] Element Type Hexahedral-Free/Sweep Mesh Select [Layer Structure]

Model (2D Analysis)

 

Model (3D Analysis)

Divide the body beforehand such that meshes are created regularly with hexahedral mesh by sweep mesh.

Body Attributes and Materials

Body Number/Type	Body Attribute Name	Material Name
0/Face	Air	000_Air *
1/Face	Board	006_Glass_epoxy *
2/Face	Foil	008_Cu *
3/Face	Terminal	008_Cu *
4/Face	Solder	LiquidSolder

* Available from the material DB

 

The material property of LiquidAir is set as follows. For a stable calculation of the steady state, a high viscosity value is set.

Material Name	Tab	Settings
LiquidSolder	Solid/Fluid	Liquid
	Density	7400 [kg/m3]
	Viscosity	400 x 10^-3 [Pa s]

 

The contact angle is set in the body attributes of Board.

Body Attribute Name	Tab	Settings
Board	Solid	Multiphase Flow Setting (Contact Angle Setting): Specify for each body attribute: Select Phase Pair Setting: Phase 1 Phase 2 Contact Angle 000_Air LiquidSolder 180

Boundary Condition

Boundary Condition Name/Topology	Tab	Boundary Condition Type	Settings
Sym/Edge	Symmetry/Continuity	Symmetry(*)	Select [Symmetric Face]
Outer Boundary Condition	Fluid	Inlet/Outlet	Natural Inflow/ Natural Outflow

 

Results

The volume fraction contours of phase 2 at 0 [s], 0.01 [s], 0.03 [s], and 0.04 [s] are shown below.

The part of phase 2 (LiquidSolder) is illustrated in red.

The results at 0.03 [s] and 0.04 [s] are similar. They show the solder shape in equilibrium.

 

0.0 [s]
0.01 [s]
0.02 [s]
0.03 [s]
0.04 [s]

 

 

The results of the 3D analysis are shown below.

The contour on the cross section and the isosurface contour are shown below. The surface of 0.5 is the boundary between solder and air.

The isosurface contour is displayed in gray.

 

0.0 [s]
0.01 [s]
0.02 [s]
0.03 [s]
0.04 [s]