Example of 3D Injection Molding CAE Directly Connected with 3D CAD

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Ashley Gilmore
6 years ago
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1 3D TIMON Example of 3D Injection Molding CAE Directly Connected with 3D CAD 1

2 Background Problem of Data Translation from 3D CAD to CAE 3D TIMON Difficulty to Generate mesh Automatically Topologically Irregular Structure Complicated & Thin Geometry Difficulty to Solve with Coarse Mesh We need robust mesh generator & CAE solver 2

3 Automatic FE Mesh Generation Selection of mesh generation method 3D TIMON Advance Front Mapped Voxel A.F Map Voxel Robustness C A A Human Operation A C A Mesh Control B A A Accuracy A A C 3

4 3D TIMON Development of Voxel Meshing with Moving Nodes Triangular Surface Facets of STL format to define the part Geometry. Grid cells are generated by ray casting technique. ( parallel to global Cartesian coordinates axis) Free Surface Nodes are translated on STL facets and Inner Nodes are moved by Laplace Smoothing Method. 4

5 3D TIMON Moving Nodes Procedure Element Qualities Check (Volume, Distortion, Inner angle...) to keep the simulation accuracy. Iteration of Surface Nodes Moving and Smoothing Volume Error Convergence or Element Quality Limitation is the base of judgements Volume Error [%]=(Vm-V0)/V0*100 Vm : Total Mesh Volume V0 : Original Model Volume Human Operation Time is less than 15 Minutes 5

6 3D TIMON 3D Filling/Holding Simulation Basic Equations Darcy s Law Ui =-S( µ,xj) P/ Xi Viscous Flow P/ Xi = µ 2 Ui/ Xi Xj Incompressible (Filling) / Compressible (Holding) Mass Conservation ρ / t + divρu = 0 Energy Equation ρcp T/ t = λ 2 T/ Xj Xj+ µ γ 2 Equation of State V = F(P,T), Tc = G(P) Speedy and Stable system even with Rough Mesh Potential viscous flow assumption Conductance => Pressure => Temperature => Flow Front 6

7 Additional Assumption for One Layer Solid Mesh Thin & Complicated Geometry causes One Layer Mesh 3D TIMON In one layer solid, flow is assumed Two Dimensional and Hele-Shaw type conductance is applied. One Dimensional FDM for Temperature Calculation. ( 20 Nodes through thickness ) Thickness 7

8 Verification of Cavity Pressure Resin : PC (Non Reinforced) Condition : ti 0.9sec, Tresin 330C, Tmold 100C 3D TIMON 8

9 Inference of Mesh Configuration to Pressure Calculation 3D TIMON Volume Error increases with increasing angle of STL shape inclined around global axis Angle [deg] Volume Error [%] Angle θ Angle = 30 degree 9

10 Mesh Configuration when Highly inclined 3D TIMON Angle [deg] Vol Err[%] # Nodes # Elems 45 Degree Z X Initial Grid Pitch has been set to 2 mm As angle increased, surface nodes move long and elements deformation get severe. 10

11 Effect of Volume Error Peak Pressure at Just Fill GF 0% Sensor 1-3 3D TIMON Calculated pressure decrease as increasing angle when angle > 15 GF 30% Because Flow Conductance Sensor 1-3 increase with volume error 11

12 Effect of Volume Error Pressure Difference Ratio Angle P.D.R= Pc-P0 /P0 Pc:Peak at Angle>0 P0:Peak at Angle =0 Volume error should be < 10 % to keep Mesh Dependency of Pressure smaller than 20%. 3D TIMON 12

13 Effect of Number of Layers Peak Pressure at Just Fill GF 0% GF 30wt% Three Layers 3D TIMON 2 layers mesh shows relative high pressure. Inference of number of layers is less than 18%. 13

14 Example of Mesh Generation Portable Phone 3D TIMON # of Nodes # of Elements Volume Error 9.2% STL Facets Brick Elements 14

15 Example of Mesh Generation Plastics Shaft 3D TIMON # of Nodes # of Elements Volume Error 3.3 % 15

16 3D TIMON TORAY Integrated Molding New system Example of Mesh Generation Intake Manifold # of Nodes # of Elements Volume Error % 16

17 3D TIMON Examples of Volume Error Part # Nodes # Elems Vol.Err. [%] Portable Phone Video Camera Printer Cover Watch Frame Battery Case Connector

18 Fiber Orientation & Warpage Basic Equations Orientation Tensor Change of Tensor aij = pipjψ(p)dp Daij/Dt = F(aij,aijkl,ω,γ,CI) Mechanical Properties <T>= T(P) ψ(p)dp Pi : Cartesian Components of Unit Vector P 3 P ψ(p) ω,γ :Probability Density Function :Vorticity & Strain Tensor CI :Coefficient of Fiber Interaction 1 2 <T> T(p) :Averaged Property Tensor :Transversely Isotropic Tensor of Unidirectional Alignment 18

19 Verification of Warpage with Fiber Orientation Gate Plate Shape Rib Height Resin 150*50*t2 mm 3,5,10 mm PBT GF 30 wt% Condition ti 1.0sec, Tresin 250 C, Tmold 80 C, P2 20MPa, th 5 sec, tc 15 sec Warpage 19

20 Verification of Warpage with Fiber Orientation Calculated Fiber Orientation & Thermal Expansion of Arrow Direction 20

21 Verification of Warpage with Fiber Orientation Warpage 21

22 Application of Warpage Analysis to Metal Inserted Molding Reaction Force on Metal Surface by Shrinkage is analyzed to evaluate the inner void failure. 23 Resin : PA6 GF30 wt% 3 Gate4 Tmold : 80 C Tresin : 270 C Gate3 17 ti : 1.0 sec Gate1 1 Gate2 tc P2 : sec : 10Mpa 22

23 Application of Warpage Analysis to Metal Inserted Molding Filling Pattern Fiber Orientation Thermal Expansion 23

24 Application of Warpage Analysis to Metal Inserted Molding High Tensile Stress shows the possibility of Void Failure Shrinkage & Max Principle Stress Max Principle Stress Vector 24

25 Application of Warpage Analysis to Metal Inserted Molding Reaction Force[N] Gate1 Gate2 Gate3 Gate Gate3 Gate1 1 Gate4 17 Gate2 + Force Position of Insert Surface 25

ENHANCED STRUCTURE CAE SOLUTION WITH MOLDING EFFECT FOR AUTOMOTIVE PARTS

ENHANCED STRUCTURE CAE SOLUTION WITH MOLDING EFFECT FOR AUTOMOTIVE PARTS Allen Y. Peng*, Wen-Hsien Yang, David C. Hsu CoreTech System Co., Ltd., HsinChu, Taiwan, ROC Abstract An increasing number of automotive