Pultrusion is a continuous manufacturing process for polymer composites (Figure 1). The continuous reinforcements are aligned longitudinally and pulled through a resin bath for their impregnation. The impregnated reinforcements enter a heated die where the curing process takes place. The cured section continues to be pulled in order for the process to be repeated for the raw materials behind it. The pultruded part is cut to size by a saw located at the end of the line, as it reaches the desired length.
HIPPAC aims to improve and facilitate the utilisation of the pultrusion process to develop new advanced composite profiles.
Figure 1 Exel Composites pultrusion process
An in-line Quality Assessment (QA) System (Figure 2) has been developed to inspect composite profiles at the pultrusion line. This monitoring system provides a quality signature at the point of production, thus eliminating time consuming post-process inspections.
Figure 2: HIPPAC pultrusion line monitoring system
The developed digital tool is used in combination with innovative monitoring and control solutions for the development of a dynamic model. This enables the closed loop control of the pultrusion process, reduction of line preparation time and evaluation of the mechanical performance of the final part. The digital tool workflow and methodology are illustrated in Figure 3. The main output of the digital tool are the degree of cure at the exit of the die and the distribution of the temperature of the pultruded composite during processing (Figure 4).
Figure 3: Schematic diagram of the digital tool workflow
Figure 4 Illustration of temperature distribution for the pultrusion speeds of 0.6 [-/min], 0.8 [-/min], and 1.0 [-/min] in a) the composite part and b) die.
An experimental campaign will be undertaken for the validation of the output from the digital model and monitoring system. The activities will include destructive (Figure 5) and non-destructive testing.
Figure 5: Illustration of destructive test setup