Layer-Paused FFF-Based Manufacturing of PLA-Hemp Composites: Mechanical Behavior and Failure Morphology

Abstract

In this study, polylactic acid (PLA)-hemp composite samples were fabricated using a layer-paused fused filament fabrication (FFF) method, in which natural hemp fibers were manually inserted into pre-designed internal channels generated via computer-aided design (CAD). The novelty of this work lies in the introduction of a simple yet effective manufacturing approach that enables the direct integration of continuous natural fibers into the FFF process without requiring filament modification. This approach allows controlled fiber alignment and improved structural performance while maintaining the accessibility and sustainability of the FFF technique. Mechanical testing revealed that hemp fiber reinforcement increased the maximum tensile force from 1545 N to 1999 N (30%), while the displacement at maximum force decreased from 7.8 mm to 7.2 mm (8.7%), indicating a moderate reduction in ductility. Scanning electron microscopy (SEM) further confirmed the presence of fiber pull-out and interfacial separation as dominant fracture mechanisms. These results highlight the potential of the proposed method for advancing sustainable natural fiber-reinforced composites produced via additive manufacturing.

Keywords

• Additive Manufacturing
• Fused Filament Fabrication (FFF)
• PLA–Hemp Composite
• Continuous Reinforcement

Katman Duraklamalı FFF Tabanlı PLA-Kenevir Kompozit Üretimi: Mekanik Davranış ve Hasar Morfolojisi

Öz

Bu çalışmada, bilgisayar destekli tasarım (CAD) ile oluşturulan önceden tasarlanmış iç kanallara doğal kenevir liflerinin elle yerleştirilmesiyle, katman duraklatmalı ergitilmiş filament imalatı (FFF) yöntemi kullanılarak polilaktik asit (PLA)-kenevir kompozit numuneleri üretilmiştir. Bu çalışmanın yeniliği, filament modifikasyonu gerektirmeksizin sürekli doğal liflerin doğrudan FFF sürecine entegre edilmesine olanak tanıyan basit ancak etkili bir üretim yaklaşımının sunulmasıdır. Bu yaklaşım, lif yönelimini kontrol edilebilir kılmakta ve yapısal performansı iyileştirirken FFF tekniğinin erişilebilirliğini ve sürdürülebilirliğini korumaktadır. Mekanik testler, kenevir lifi takviyesinin maksimum çekme kuvvetini 1545 N’den 1999 N’ye (%30) artırdığını, maksimum kuvvette yer değiştirme değerini ise 7.8 mm’den 7.2 mm’ye (%8,7) düşürdüğünü ortaya koymuş, bu durum süneklilikte orta düzeyde bir azalmaya işaret etmiştir. Taramalı elektron mikroskobu (SEM) analizleri, baskın kırılma mekanizmaları olarak lif çekilmesi ve ara yüzey ayrılmasının varlığını doğrulamıştır. Elde edilen sonuçlar, önerilen yöntemin eklemeli imalat ile sürdürülebilir doğal lif takviyeli kompozitlerin geliştirilmesi açısından potansiyelini vurgulamaktadır.

Anahtar Kelimeler

• Katmanlı İmalat
• Eritilmiş Filament Biriktirme (FFF)
• PLA–Kenevir Kompoziti
• Sürekli Takviye

Kaynakça

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