Pultrusion of Thermoplastic Composites - New Developments and Modelling Studies

Abstract

Objective of this study is to present new developments in thermo-plastic pultrusion (a pullbraiding process combined with a contact preheating system, and a new online forming method for pultruded profiles) and a new approach for modelling of the preheating process. After modelling of the preheating process of commingled glass fibre/polypropylene yarn, the preheating of a thermoplastic pultrusion line to produce profiles with unidirectional reinforcement in axial direction was modified by adding contact heating pins. Compared to the convective heating used before, profiles with higher qualities could be produced at three times higher processing speeds. First trials of a combined braiding and pultrusion process, also with contact preheating, led to promising results. Furthermore, a process to post-form pultruded profiles immediately after leaving the heated pultrusion die was developed, leading to profiles with a forming radiusof 10 cm.

An Experimental Study of the Pultrusion of Carbon Fiber-Polyamide 12 Yarn

“…However, by using the contact pin device, the shear strength 'starts' to decrease at a pulling speed of around 20 cm/min while the void content increases. Finally, while using a combination of hot air ovencontact pins, it is evident that higher shear strength and low void content are achieved even at high pulling speeds, which confirms the efficiency of such a preheating combination [16], where heat transfer is considerably enhanced.…”

“…The shear strength is known to be more sensitive to process variations than the bending strength or modulus, because numerous parameters influence this property: the fiber-matrix adhesion, the properties of the matrix and the fibers, the void content, and the matrix crystallinity [9,16]. It was determined using an interlaminar shear device (ISD) also called compression shear device (CSD) developed by Lauke et al [17,18] for small sections of filament wound rings.…”

“…The fiber bundles were pulled over the first pin, under the second one, and finally over the third one. This enables a quick and homogeneous heat repartition over the fiber bundles and an accelerating preheating process [14,16].…”

The pultrusion process for polymer matrix composites

“…Michaeli and Juerss (1996) presented results indicating that thermoplastic pull-braiding (reinforcing and polymer fi bres are mingled together in dry form) of complex-shaped profi les is also possible. Bechtold et al (2002) presented a pull-braiding process combined with a contact preheating system for commingled glass fi bre/polypropylene yarns. In the study by Hidekuma et al (2008), unidirectional fi bres were covered with braided yarns to reduce the anisotropy.…”

The Processing Design of Jute Spun Yarn/PLA Braided Composite by Pultrusion Molding

“…Pultrusion is a manufacturing process in which reinforcing fibers impregnation with matrix is pulled through a die to form composites of a constant cross-section. Generally, the unidirectional fibers are impregnated with low viscosity thermosetting resins before passing through a series of dies for shaping and curing during pultrusion process [1][2][3]. While thermoset pultrusion is a well-known and commercially established manufacturing method, there is less knowledge about the thermoplastic pultrusion.…”