High-Performance Composites is read by qualified composites industry professionals in the fields of continuous carbon fiber and other high-performance composites as well as the associated end-markets of aerospace, military, and automotive.
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250 12 kW Heating 200 42 kW Cooling 60 l/min pump 100 150 50 0 0 5 10 15 20 25 30 35 40 45 50 55 60 65 Table 2. Oil Temperature Control Unit vs. Tool Heating/Cooling Pro���les Flow rate: 28 L/minute Temperature (��C) Average temperature delta between TCU and tool: 35��C Flow rate: 25 L/minute Temperature (��C) Average temperature delta between TCU and tool: 8��C Table 1. Pressurized Water Temperature Control Unit vs. Tool Heating/Cooling Pro���les 250 24 kW Heating 200 116 kW Cooling 100 l/min pump 100 150 50 0 0 5 10 15 Time ( Minutes) Water Cooling Tool Cooling Water Heating Oil Cooling Tool Heating Table 3. Temperature vs. location ��� Water and electric Heating with One-hour Soak Oil Heating 40 Tool Heating 45 50 55 Cooling Table 4. Temperature vs. location ��� Water and electric Heating with Two-hour Soak 190.0 180.0 180.0 170.0 170.0 Temperature (��C) 190.0 Temperature (��C) 20 25 30 35 Time ( Minutes) 160.0 150.0 140.0 160.0 150.0 140.0 130.0 130.0 0 Water 1-mm sample 2 4 Water 2-mm sample 6 Location 8 10 Electric 1-mm sample cles were more consistent. The average temperatures measured at the same location on the mold surfaces during the two-hour test period were 1.94��C for the pressurized water TCU and 6.7��C for the electric cartridge system. Another important distinction, Petrykowski notes, was the difference in temperature over the length of a part. The average temperature differential across one part at the same moment was 21.0��C during the electric cartridge trial; the average differential for the pressurized water trial was only 2.7��C. A temperature differential as large as that recorded over the length of one 12 Electric 2-mm sample 0 Water 1-mm sample part in the mold that was heated by the electric cartridge could result in crystallinity variations within the part, Petrykowski contends. This, in turn, could result in shrinkage differences throughout the part, producing molded-in stress that could manifest in part warpage, creep and physical property differences within the same part. To determine if the parts produced with each TCU attained acceptable levels of crystallinity, they were analyzed via differential scanning calorimetry (DSC) to determine the percentage of crystallinity. The DSC results demonstrated that the parts produced in the water-heated mold 2 4 Water 2-mm sample 6 Location 8 Electric 1-mm sample 10 12 Electric 2-mm sample had consistent and acceptable crystallinity along their lengths. For the parts produced in the electric cartridge-heated mold, however, different crystallinity percentages were measured along the test parts��� lengths. These new data, says SINGLE, clearly demonstrate that pressurized-water TCUs can not only meet the needs of composites manufacturers but also can do so ef���ciently and economically. This capability could prove bene���cial as the advanced composites manufacturing community continues to evolve toward more fast-cycle, rapid-cure, out-of-autoclave (OOA) fabrication processes. january 2013 | 25