| 摘要 |
Apparatus for pultruding thermoplastic, resin-impregnated, fibrous substructures heats the substructures to a temperature just below the melting temperature of the resin. The heated substructures are then simultaneously pulled through a passage to conform them to a desired cross section. At least a portion of the perimeter of this passage is formed by a wave guide. The wave guide is vibrated at ultrasonic frequency in a predetermined direction so as to direct the ultrasonic vibration into the substructures within the passage. The application of the ultrasonic vibration stimulates the flow of the resin in the heated substructures. Pressure is applied to the flowing substructures within the passage to consolidate them into an integral structure conforming to the chosen profile. The ultrasonic vibration at low power input does result in some heat transfer to the profile, but the flow rates of the resin exemplify an increase in flow far greater than expected in relation to the temperature increase. The result of the application of ultrasonic vibration to the resin impregnated fibers in their unmelted state is a pultrusion process which can comfortably operate at pull rates considerably better than other processes while producing a highly uniform product.
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