Enabling Technology to Lightweight Automobiles - SPE ACCE presentation

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Presentation delivered at the 10th Annual Society of Plastics Engineers, Automotive Conference and Exhibition - Troy MIAcrolab - SPE ACCE -- The ISOMANDREL - An Enabling Technology to Lightweight Automobiles

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Enabling Technology to Lightweight Automobiles - SPE ACCE presentation

  1. 1. New Methodology Heat Pipe Thermally Enhanced (HPTE) Mandrels In Filament Winding Applications
  2. 2. Heat pipes Well Established in Automotive Tooling 1
  3. 3. Heat pipes What value does heatpipe technology bring to mandrel design and filament winding process optimization? 1
  4. 4. Heatpipe Operating Principles 2
  5. 5. Heatpipe Features & Benefits  Heatpipes transfer large amounts of thermal energy rapidly.  Heatpipes are intrinsically Isothermal.  Heatpipes redistribute localized energy inputs.  Heatpipes have an Intuitive, remediating response to locally generated energy deficit and surplus transients. (sinks and exotherms)  Heatpipes require no electrical power or mechanical connections.  Heatpipes are sealed systems. 4
  6. 6. HPTE Mandrels “In Oven” Convection Oven Curing of Filament Wound Tube Sections 3
  7. 7. Current “In Oven” Cure Challenges and Limitations  The cure sequence usually occurs in a heated convection oven or radiant energy environment.  Energy is provided to the surface of the resin/filament composite through the heated oven atmosphere at low watt density.  A large percentage of energy produced by the oven is vented and not efficiently utilized. 3
  8. 8. Current “In Oven" Filament Winding Cure Challenges and Limitations  The mandrel is not directly heated.  The mandrel is the last component to be heated.  The cure is initiated at the outside surface of the winding, sealing the outer surface of the tube section, trapping gasses and vapour liberated during the cure cycle.  Trapped gasses and vapours contribute to delamination and porosity. 3
  9. 9. HPTE Mandrel Testing Cell 5
  10. 10. Traditional Mandrel Test Results Transient Temperature Curves for the Hollow Mandrel 140 Top (2") Mid (33") 120 Bottom(60") Delta T (bottom-top) 100 Surface Temp. (deg.F) 80 60 40 Date: Jan. 9, 09 Sand Bath Temp. 350 Deg. F Heat Transfer Rate: ~12W. 20 Mandrel OD. 1.875". Mandrel Length: 72". TC location is the distance from the top. 0 0 5 10 15 20 25 30 35 40 45 Time (Min.) 6
  11. 11. HPTE Mandrel Test Results Transient Temperature Curves for the Mandrel-Isobar 260 240 220 200 180 Surface Temperature (deg. F) 160 140 Top (2") 120 Date: Jan. 8, 09 100 Mid (33") Sand Bath Temp. 350 Deg. F 80 Bottom (62") Heat Transfer Rate: ~210W. Mandrel OD. 2". 60 Delta T (bottom-top) Mandrel Length: 74". 40 TC location is the distance from the top. 20 0 -20 0 10 20 30 40 50 60 70 80 90 100 Time (Min.) 7
  12. 12. HPTE mandrels thermodynamic features in conventional oven curing applications  Exposed surfaces of the HPTE mandrel absorb thermal energy from the oven and transfer it directly to the mandrel.  This absorbed thermal energy is immediately redistributed throughout the HPTE mandrel.  The redistributed thermal energy results in a dynamically isothermal mandrel.  The heated isothermal mandrel provides an optimum uniform cure platform providing thermal energy from I.D. to O.D. of the tube section. 8
  13. 13. HPTE mandrels in convection oven curing applications thermodynamic benefits  The mandrel is now thermally uniform. (isothermal) and super thermally conductive and reactive to the ambient temperatures within the oven.  Resident energy within the oven is absorbed through the exposed ends of the mandrel, heating the mandrel directly and efficiently.  Because both the I.D. and O.D. surfaces of the winding are now actively heated, the cure cycle time is reduced.  The heated mandrel draws resin to the I.D. of the winding resulting in a tube section with a homogeneous, resin rich, nonporous surface on the tube inner diameter. 9
  14. 14. HPTE Mandrels “Out of Oven” Induction Curing of Filament Wound Tube Sections After Winding 3
  15. 15. Induction cure sequence using a HPTE Mandrel winding and curing a 3” I.D. Tube section with ½” wall using carbon fiber epoxy prepreg 14
  16. 16. HPTE mandrels in induction heated “out of oven”curing applications  The induction heating coil is situated proximate to the mandrel permitting unimpeded mandrel rotation.  Induction heating is relatively instantaneous and intense.  RF energy is invisible to the uncured resin and filament but fully sensed by the metal mandrel.  Significant thermal energy per unit time can be provided to the mandrel which then intimately transfers that energy to the uncured composite resulting in significant energy efficiencies. 10
  17. 17. Testing Cell for Induction heating of both a HPTE Mandrel and a Traditional Mandrel 11
  18. 18. 3” Standard hollow mandrel: Thermographic study with induction heat 187.70 ºF 12
  19. 19. 3” HTPE mandrel: Thermographic study with induction heat 183.02 ºF 13
  20. 20. Traditional hollow mandrel vs. HTPE mandrel 64” X 3” rotating at 100 RPM and heated by an induction coil providing 850 Watts Time lapse video sequences
  21. 21. HPTE Mandrels “Out of Oven” Induction Curing of Filament Wound Tube Sections While Winding 3
  22. 22. Video of a cure while winding sequence using a HPTE Mandrel winding and curing a 3” I.D. tube section wound of carbon fiber epoxy prepreg 15
  23. 23. HPTE mandrels in induction heated “out of oven” curing applications  The mandrel now provides the uncured composite with 100% of the thermal energy requirement. The cure begins at the mandrel surface and continues through to the tube section outside diameter.  Curing from the inside diameter to the outside surface allows volatile vapours generated during the cure sequence to be liberated to atmosphere reducing porosity.  Resin is drawn to the hottest surface during the cure resulting in a resin rich non porous I.D. 10
  24. 24. SAMPLE A Induction Cure vs. SAMPLE B Oven Cure CT Scan Defect Analysis
  25. 25. A: Induction Cure Marker
  26. 26. B: Oven Cure
  27. 27. A: Induction Cure B: Oven Cure
  28. 28. Sample A: Induction Cure Volume: 1288.8789 mm3 Defects: 2.7777 mm3 Porosity: 0.21505 % Defect Volume Distribution vs. Defect Count
  29. 29. Sample B: Oven Cure Volume: 1452.3339 mm3 Defects: 2.7764 mm3 Porosity: 0.19080 % Defect Volume Distribution vs. Defect Count
  30. 30. Sample A: Induction Cure Volume: 1288.8789 mm3 Defects: 2.7777 mm3 Porosity: 0.21505 % Volume: 1452.3339 mm3 Sample B: Oven Cure Defects: 2.7764 mm3 Porosity: 0.19080 % Defect Volume Distribution vs. Defect Count
  31. 31. Technology providers for this project  Ameritherm Div of Ambrel Corp, Springfield NY Induction power supply and coil  Chino Works America, Chicago Illinois Infrared sensor and process controller  McClean Anderson, Schofield Wisconsin Filament winding machine and laboratory  TCR Composites, Ogden Utah Prepreg epoxy filament materials  Acrolab Ltd, Windsor Ontario, Canada HPTE mandrel 16
  32. 32. Thank you Joseph Ouellette Director, Advanced Research & Development Acrolab Ltd. Advanced Thermal Engineering /Research and Development Windsor, Ontario, CANADA www.acrolab.com

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