Flow Analysis Steps Introduction Aim Review steps involved

Flow Analysis Steps

Introduction § Aim – Review steps involved in a flow analysis § Why do it – Every part is different – Basic analysis steps the same – Analysis objectives different § Overview – Concentrate on steps of filling – Look at § Packing § Cooling § Warpage

Moldflow Design Philosophy § Number of gates – Based on the pressure to fill the cavity – Minimum number of gates to fill the cavity § Position of gates – Position gates to achieve a balanced fill § Flow pattern – Straight fill pattern – No changes in direction during filling § Unidirectional

Moldflow Design Philosophy § Runner Design – Balanced filling of all cavities – Minimum volume § Sequence of Analysis – Optimize the cavity first – Design the runners to properly fill/pack the part(s)

Project Design Procedure Using Moldflow § Determine the analysis objectives for the project § Discuss the project with all disciplines involved § Use previous experience of analyst § Use Moldflow Design Principles § Use Moldflow Design Rules with the software § Interpret results and make changes where necessary § Discuss changes with all disciplines involved § Repeat analysis until acceptable results achieved

Optimize Fill Possible Solution A Determine Analysis Objectives Review Results 1 Prepare FE Mesh 2 Select Material Fill Problems Resolved? Y 3 Select Gate Location Select Molding Machine 4 Determine Molding Conditions 5 Set molding Parameters Run Analysis A N End Problem Possible Solution Short Shot 1, 2, 3, 4, 5 Poor Filling Pattern 1, 2, 3, 5 Poor Weld Lines 1, 2, 3, 4, 5 Air Traps 1, 2, 3, 5 High Stress 1, 2, 3, 4, 5 High Pressure 1, 2, 3, 4, 5 High Clamp Force 1, 2, 3, 4, 5 NOTE: The Fill process assumes that the model is of the part only and does not contain a feed system.

Determine Analysis Objectives The Most Important Step § Will the part fill? § Are the ribs too thick? § What material should be used? § Can the part be packed enough? § What are optimum processing conditions? § Will the snap fit break? § Where should the gate be? § Are the runners balanced? § How many gates are required? § What size should the runners be? § Where will the weld lines be? § Can the runner volume be smaller? § Are there air traps? § Is the gate the right size? § How thick should the part be? § Is the cooling uniform? § Is the flow within the part balanced? § Will the part warp within tolerance? § Are the ribs too thin to fill? § Is the press big enough?

Prepare FE Mesh § May need to iterate if mesh is not clean from CAD system Prepare FE Mesh Try 2 Prepare CAD model Import CAD model Try 1 Set Mesh Densities, Global & Local Generate Mesh Evaluate Mesh N Initial Mesh Good? Y Clean up Mesh Verify Mesh is Clean End

Optimize Flow § Adds to Fill – Runner optimization – Cooling analysis § Optional § Highly recommended – Packing analysis Optimize Fill Balance/Size Runners Cooling analysis? N Optimize Packing Profile End Y Optimize Cooling

Optimize Part § Adds to Flow – Warpage optimization Optimize Fill Balance/Size Runners Cooling analysis? N Optimize Packing Profile Optimize Warpage End Y Optimize Cooling

Optimize Warpage § Solving involves iterations back to previous work Determine Analysis objectives: Warpage Definition & tolerance Or Optimize Fill Or Balance / Size Runners Or Optimize Cooling Or Optimize Packing Profile Reduce Warpage Determine Warpage Magnitude Determine Warpage Cause Is Warpage Acceptable? Y End N

QUESTIONS?