On-site evaluation of a modified pultrusion process: Fibre spreading and resin injection-based impregnation

Abstract

The focus of the current research was to demonstrate a modified pultrusion technique at an industrial site using a commercial production machine. In this instance, the conventional resin bath was replaced by a custom-designed compact impregnation unit. The dimensions of the impregnator were 310 mm × 400 mm × 9 mm. The relatively short length of the impregnator, when compared to a 5 litre resin bath, meant that it had to be efficient in impregnating the reinforcing fibre bundles. This was achieved using a fibre spreading unit and a facility to inject the resin under low-pressure. The design basis for the fibre spreading unit and the impregnator are presented along with the methodology that was used to select the pultrusion speed and die temperature. The pultrusion experiments were performed using filled and unfilled vinyl ester resin and E-glass fibres. The profile of the 0.5 metre-long die was rectangular with dimensions of 32 mm × 2.2 mm. The fibre spreading unit and the impregnator were retrofitted to the pultrusion line with ease. The physical, mechanical and thermo-mechanical properties were determined for the pultruded composites using the resin bath and the modified technique. The properties of the latter were found to be equivalent or marginally superior when compared to the resin bath-based production method. However, in the modified pultrusion technique, when compared to conventional resin bath-based pultrusion, the volume of waste resin generated was 97% lower. The volume of solvent required to clean the equipment after production was reduced by 90%.

Effects of additives on the cure kinetics of vinyl ester pultrusion resins

“…11,12 Then, excess resin is removed at the collimating plates, and the preformed reinforcement pack is introduced into the heated die block where polymerization takes place. 13,14 When the process becomes stationary, it requires very little attention from the engineer as the pulling units and cutting saw operate in an almost fully automated manner. 15,16 Engineers widely use mathematical models to optimize composite manufacturing processes, thus avoiding costly trial and error experiments.…”

Characterisation of Curing of Vinyl Ester Resin in an Industrial Pultrusion Process: Influence of Die Temperature

“…In addition, Vinnepas B60 and an internal mould release agent INT-PUL-24 (Axel Plastics, Monroe, CT, USA) were utilised in the final resin mix. The flat bar product manufactured is 56 mm wide and 3.25 mm thick and contains 82% unidirectional glass fibres by weight, measured using ASTM D2584 [ 40 ].…”

Cost-efficient, automated, and sustainable composite profile manufacture: A review of the state of the art, innovations, and future of pultrusion technologies

“…Irfan et al [92] developed a modified pultrusion process which consists of a fibre spreading unit. This spreading unit provided better lateral spreading and reduced roving thickness, and this resulted in better impregnation and lower void content [93]. Van De Steene et al [94] applied passive and active spreading methods into a small scale pultrusion die.…”