Investigations on injection molded, glab-fiber reinforced polyamide 6 integral foams using breathing mold technology

Abstract

Investigations on PA6-GF50 integral foams have been carried out using different material systems: longfiber-And shortfiber-reinforced PA6 as well as unreinforced PA6 as a reference material. Both chemical and physical blowing agents were applied. Breathing mold technology (decomprebion of the mold) was selected for the foaming proceb. The integral foam design, which can be conceived as a sandwich structure, helps to save material in the neutral axis area and maintains a distance between load-bearing, unfoamed skin layers. For all test series an initial mold gap of 2.5mm was chosen and the same amount of material was injected. In order to realize different density reductions, the mold opening stroke was varied. The experiments showed that, at a constant mab per unit area, integral polyamide 6 foams have a significantly higher bending stiffneb than compact components, due to their higher area moment of inertia after foaming. At a constant surface weight the bending stiffneb in these experiments could be increased by up to 600 %. Both shortfiber-And longfiber-reinforced polyamide 6 showed an increase in energy absorption during foaming.