Research on compression molding and curing process of <scp>CFRP</scp>/steel laminates

Abstract Metal and Carbon Fiber Reinforced Polymer (CFRP) laminates exhibit excellent mechanical properties and lightweight advantages, leading to increasing applications in automotive part manufacturing. Compared to the high costs and low efficiency of autoclave processing, the compression molding method of laminates has the characteristics of low cost and high efficiency, making it suitable for the mass production of the automotive industry. In this paper, four kinds of compression molding processes were designed according to the curing degree of resin before forming, and the influence of the curing degree of resin on the mechanical properties and surface accuracy of CFRP/DC01 steel hybrid parts was studied. The bending strength, energy absorption, shape accuracy and thickness distribution of formed parts were systematically evaluated. Experimental results indicated that as the resin curing degree increased, the formability of the laminates decreased, resulting in reduced mechanical properties of the hybrid parts. Cross‐sections microscopic morphology of the formed part showed that there were serious defects of delamination and fiber fracture in the parts formed after the resin was cured completely, and the bending strength and shape accuracy were the worst. Compared with the 120‐min full curing of the resin in the dies of technique 1, the technique 4, which combined 5‐min pre‐curing in the dies with full final curing in the aging furnace, could greatly improve the production efficiency of the parts. The parts produced by technique 4 could ensure good mechanical properties and high surface accuracy. Highlights A new compression molding and curing process enhanced mechanical properties of CFRP/steel hybrid parts. The process balanced high performance with reduced production time. The bending strength, energy absorption capacity and shape accuracy of formed parts were obviously enhanced. The effect of resin curing degree on the formability of laminates was studied.