Determination of optimum cure parameters of 977‐2A carbon/epoxy composites for quickstep processing

Abstract

In this study polymer-matrix composite has been processed using autoclave and Quickstep techniques. A phenomenological approach was adopted for the optimization of cure cycle for Quickstep of an aerospace grade epoxy composite (Cycom 977-2A carbon/epoxy prepregs). Though there are reports concerning the processing and properties of materials using Quickstep technique, little work has been reported on the design of optimized cure cycle for Quickstep processing based on rheology, ultrasonic testing, and mechanical characterization. A step by step account is provided in this study, describing the introduction, balancing and combination of isothermal dwell periods and temperature ramps in order to control the resin viscosity. All the panels manufactured were qualitatively assessed using ultrasonic C-scan and afterwards fiber and void content, panel thickness, flexural strength, and interlaminar shear strength (ILSS) were assessed and compared with those obtained from traditional autoclave-and oven-cured laminates. The Quickstep panel properties produced from optimized cure cycle was superior to oven curing and was comparable with autoclave.

Cure characterization of Cycom 977‐2A carbon/epoxy composites for quickstep processing

“…The T g and final polymer network structure were examined using DMA and FTIR. Furthermore, our comprehensive study regarding the physical and mechanical properties of panels cured in autoclave and Quickstep has also been reported in literature , where the properties of Quickstep cured panels were found to be comparable to autoclave cured panels. In the previous study, QS‐60 (Quickstep cure cycle with intermediate dwell time of 60 min) cured panel showed a significant improvement in mechanical properties compared with the other Quickstep‐cured cycles.…”

“…The three cure schedules employed for Quickstep processing are listed in Table . An optimized cure cycle (QS AD ) was designed, based on the rheology of neat 977‐2A resin and physical and mechanical performances of the laminates manufactured by using this cycle were compared with those cured in autoclave, oven, and two other Quickstep cycles (QS Direct and QS ID ) . The information from rheological analysis however, was used for the void reduction in the panel when resin was not gelled.…”

“…The final degree of cure was strongly dependent on the time spent at the upper cure temperature. The intermediate dwell time and temperature, however, were used to control the resin flow, fiber wetting, and void removal as explained earlier .…”

“…Consequently, considering the faster temperature ramp rates the homogeneity of the curing samples was our foremost concern. As indicated in our previous study , two thermocouples were attached to the part for the real time monitoring of the temperature in Quickstep processing as shown in all thermal profiles of Fig. and the cure cycle was based on these thermocouple readings.…”

A qualitative, process-parameter-based model for the release agent transfer during CFRP-part production: an approach to increase the initial bondability

“…autoclave process) are chosen to achieve a high interlaminar quality [13] or to reach a fast part production [14]. Unfortunately, the correlation of specific process parameters on the release agent transfer has not been investigated so far and is therefore subsequently discussed.…”