Influence of Infill Density on Structural Performance of FDM-Processed PET-G Polymer: Experimental Validation through Quadcopter Flight Testing

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This is an unedited manuscript accepted for publication and provided as an Article in Press for early access at the author’s request. The article will undergo copyediting, typesetting, and galley proof review before final publication. Please be aware that errors may be identified during production that could affect the content. All legal disclaimers of the journal apply.

Year : 2026 | Volume : 14 | 03 | Page :
    By

    Sunny Nanade,

  • Zarvan Movdawalla,

  1. Assistant Professor, Department of Mechatronics Engineering, Mukesh Patel School of Technology Management & Engineering, SVKM’s NMIMS, Mumbai, Maharashtra, India
  2. Student, Department of Mechanical Engineering, Mukesh Patel School of Technology Management & Engineering, SVKM’s NMIMS, Mumbai, Maharashtra, India

Abstract

Polyethylene terephthalate glycol-modified (PET-G) is an amorphous thermoplastic copolymer increasingly adopted in structural applications through fused deposition modeling (FDM). However, the correlation between FDM processing parameters, especially infill density, and mechanical performance of PET-G parts remains inadequately characterized under real-life loading conditions. This study investigates how infill density (10% and 30%, grid pattern) influences the structural integrity of FDM-processed PET-G components, validated experimentally through quadcopter airframe fabrication and flight testing.

Two geometrically identical X-configuration frames (450 mm motor-to-motor diagonal) were fabricated with identical processing parameters (layer height 0.25 mm, nozzle temperature 240 °C, bed temperature 75 °C, three perimeters, four top/bottom solid layers) differing only in infill density. Both frames were assembled with M3 fasteners and subjected to outdoor flight tests including hover, translation, and repeated takeoff-landing cycles.

The 10% infill frame (600 g) suffered catastrophic brittle fracture at the arm-body interface within five flights, initiating at bolt hole stress concentrations and propagating through the sparse internal polymer lattice. The 30% infill frame (690 g) completed over 20 flights without structural degradation. The threefold increase in polymer volume fraction provided significantly higher energy absorption and load distribution despite only a 15% mass increase and 5–8% reduction in flight endurance. These results demonstrate that infill density fundamentally controls effective mechanical properties of FDM-processed PET-G, and that bulk material datasheet values cannot be directly applied to printed structures.

Keywords: PET-G polymer, Fused deposition modeling, Polymer processing, Infill density, Thermoplastic mechanical properties, Additive manufacturing, Structural polymer applications, UAV frames

How to cite this article:
Sunny Nanade, Zarvan Movdawalla. Influence of Infill Density on Structural Performance of FDM-Processed PET-G Polymer: Experimental Validation through Quadcopter Flight Testing. Journal of Polymer & Composites. 2026; 14(03):-.
How to cite this URL:
Sunny Nanade, Zarvan Movdawalla. Influence of Infill Density on Structural Performance of FDM-Processed PET-G Polymer: Experimental Validation through Quadcopter Flight Testing. Journal of Polymer & Composites. 2026; 14(03):-. Available from: https://journals.stmjournals.com/jopc/article=2026/view=243561


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Ahead of Print Subscription Original Research
Volume 14
03
Received 20/03/2026
Accepted 31/03/2026
Published 12/05/2026
Publication Time 53 Days
2

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