Molding Window

Why Determine a Molding Window? Determine if the part will fill  Is pressure low enough? Small molding window indicates the part will be difficult to produce May suggest additional gates to reduce pressure Change part design to improve filling  Increase wall thickness

Analysis Inputs Required Finite Element model  Cavity-based analysis  On the part model, no runners Analysis sequence, Molding Window Material Injection location Process settings  Injection molding machine  Mold temperature  Melt temperature  Injection Time  All can be defined but normally defaults are used

Analysis Guidelines In the Advanced dialog, the parameters that control the molding window size can be set  Feasible molding window limits  Preferred molding window limits

Results Available Results Summary Zone 3D XY Graphs  Quality  Injection pressure  Minimum flow front temperature  Maximum shear stress  Maximum cooling time  Maximum shear rate Recommended Mold Temperature : C Recommended Melt Temperature : C Recommended Injection Time : s

Interpreting the Results Basic procedure for viewing results  Results summary file Look at recommended conditions  Zone plot Get a sense of the size of the molding window  Quality XY plot Set X axis to Injection time, & set mold and melt to recommended Decide to keep recommended or determine alternative conditions  Injection pressure XY Set X axis to Injection time, & set mold and melt to conditions used Check if pressure is too high  Minimum flow front temperature Set X axis to Injection time, & set mold and melt to conditions used Determine injection time of a 0ºC, 10ºC and 20ºC temperature drops Decide on injection time to use  Check remaining plots for problems

Results Summary File Review the results summary file for the recommended molding conditions  Becomes basis for viewing results  Compare to temperature ranges analyzed

Zone Plot Use cutting plane tool for manipulating Turn on all 3 planes Make Active (move) the planes to see window Look for window size  More green the better When done turn off all planes

Quality Plot Set X axis to time in result properties Set mold and melt to recommended Decide if recommended conditions are practical  In middle of the range?  Move mold and melt sliders to see effect on quality  Pick mold and melt to use  Query max quality for time

Injection pressure Set X-axis to injection time Make sure pressure not too high  Most machines the design limit should be 80 MPa  Check at specific conditions by query Pick on curve to find injection time

Minimum Flow Front Temperature Set X-axis to injection time Query graph to find the flow front temperature equal to the melt temperature  This will be the injection time where the quality is the highest Query to find 10ºC & 20ºC temp drops  Represents good window  10ºC the middle  20ºC the end

Check Remaining Plots Check to make sure no problems are present  In particular make sure the shear stress is below the design limit in the database Shear Rate Cooling Time Shear Stress

Material  Use Honeywell Plastics, Capron 8333G HS Gate locations  Center gate Design Criteria  2-plate tool  Determine optimum processing conditions for the given gate location Practice, Cover

Optional models Cell Phone  Material PC+ABS, Bayer AG Bayblend FR 2000 V-0/1.6  Design Criteria Determine which gate location is best, center or end gate Door Panel  Materials ABS, Bayer AG Novodur L3FR ABS, GE USA Cycolac T-XC  Design Criteria Determine which material is going to work best

QUESTIONS?