PLASTICS INDUSTRY
Modeling of Compression Molding Problems using PASSAGE®/COMPRESSION Software
Thin - walled geometries Hele - Shaw or Barone - Caulk model for flow Thermoplastics or thermosets	Filling and heat transfer coupled Post-fill curing Fiber orientations
Modeling of Injection Molding Problems
Thin - walled geometries Hele - Shaw model for flow Filling and heat transfer coupled Thermoplastics or thermosets	Packing and curing Mold cooling Fiber orientations
General Capabilities
Injection or compression mold flow analysis Newtonian and non-Newtonian fluids Isothermal and non-isothermal Coupled flow and energy equations Multiple gates and inserts Prediction of frozen and molten layer interfaces during filling	Fiber orientations Shrinkage and warpage analysis of parts due to cooling Analysis of packing and curing (cooling) stages Stress analysis of parts under external static and dynamic loads
Different Levels of Modeling
Isothermal filling analysis Non-isothermal filling analysis Packing and curing (non-isothermal) Mold cooling or heating Fiber orientation analysis	Warpage analysis DT due to filling, packing and curing DT due to uneven mold cooling or heating Shrinkage indices
Factors Affecting Warpage
Uneven shrinkage due to filling and packing Nonuniform temperature distribution due to mold cooling or heating Anisotropic and non-homogeneous material properties due to orientations of fibers
3-D Transient Heat Transfer
Coupled with fluid flow Frozen layer prediction Fiber orientations and warpage Layered finite element model across the cavity thickness
Fiber Orientation - Injection Molding
From Velocity Field:
Shear Layer - fibers to flow Core Layer - fibers to flow or determined from orientation tensor calculations
For Stress Analysis:
Layered composite model Locally orthotropic layers
Determine Mechanical Properties from Halpin - Tsai Equations
Fiber Orientation - Compression Molding (SMC)
Procedure:
Determine velocity field over time Find fiber orientation from solving orientation tensor equations Determine mechanical properties from: - Squeeze flow test correlations, or Halpin - Tsai equations Determine Thermal Properties from: - Squeeze flow test correlations, or Schapery's equations Perform Warpage and Stress Analysis
PASSAGE®/COMPRESSION Design and Analysis Procedure
Construct finite element mesh of part geometry. Define process conditions. Perform a non-isothermal filling analysis. If necessary, modify conditions and repeat steps 1 through 3 until favorable filling conditions are reached. Perform a fiber-orientation analysis to determine fiber orientation through the layers. Using fiber orientation information, construct a laminated composite shell model for stress analysis: - Analyze part under initial thermal strains to determine warpage. - Analyze part (warped geometry) under external loads for structural integrity.
If necessary, modify the conditions and repeat steps 1 through 6 or 5 through 6 until a satisfactory design is obtained.
Features of PASSAGE®/COMPRESSION Software
Injection and compression molding processes. Newtonian and non-Newtonian fluids. Additional material models can be incorporated. An accurate and efficient layered finite element model for thermal energy equation in thin-walled geometries. Accurate prediction of solid-fluid interfaces Multiple gates and inserts. Analysis of packing (shrinkage) and curing after mold-filling. Prediction of fiber orientations. Has built-in pre- and post-processors. Can interface with other preprocessors. Readily adaptable to specialized applications: - Injection molding - In-mold coating - Structural RIM
An Injection Molding Analysis - (Air-Conditioning System Evaporator Plate)
Geometry:
Received part drawings Imported into 3D-CAD environment Generated finite element mesh	Received mold drawings Imported into 3D-CAD environment Generated finite element mesh
Filling Analysis:
Part fill pattern is obtained
Mold Cooling Analysis:
Temperature variation over part surfaces is obtained
Warpage Analysis:
Deformed geometry of part is obtained
Filling Analysis
Melt front history Pressure and temperature results - Grid size : 1200 grid points - Run time (CPU) : 4 hours on workstation
Process Conditions
Part
Material: 20% Talc Filled Polypropylene Mold Temp: 80°F Melt Temp: 450°F Fill Time: 2 sec Flow Rate: 242 cm3/sec	Coef. Conduction: 1.94 x 104 cm2 K) Specific Heat: 2.264 x 107 K) Mass Density: 0.862 gm/cm3 Cooling Cycle: 60 sec
Mold
Material: Steel Coef. Conduction: 3.63 x 106 cm2 K)
Mold Cooling Analysis
Description of transient temperature variation in mold and over part surfaces Cooling channels modeled Interaction effects of filling included - Grid size : 23,000 grid points - Run time (CPU) : 20 minutes on a workstation
A Cycle-Averaged Mold Heating/Cooling Analysis
Accounts for transient temperature effects over part surfaces
Steps
Perform a non-isothermal filling analysis under fixed mold temperatures Continue solving heat transfer equation until ejection (cycle) time Determine final bulk temperature distribution in part Calculate amount of heat removed or added during cycle	Perform a heat transfer analysis of mold to determine cycle averaged temperature distribution in mold and part surfaces Use obtained temperature distributions for warpage predictions of part
Warpage Analysis
Displacement of part due to warpage: - Grid size : 1200 grid points - Run time (CPU) : 10 minutes on a workstation