# Assessment of the Drone Arm’s Plastic–Metal Joint Mechanical Resistance Following Natural and Artificial Aging of the 3D-Printed Plastic Component

## TL;DR

This study examines how 3D-printed drone arms with plastic-metal joints hold up over time under various environmental conditions.

## Contribution

The study introduces wettability analysis for PLA-metal joints and applies comprehensive aging protocols to these joints for the first time.

## Key findings

- Pull-out strength of the joints decreased by 70% under harsh aging conditions.
- Stress concentration was observed on the inner side of the arm via numerical modeling.
- Optimal print settings allow the arm to support a 2.31 kg payload, and inserts can withstand up to 17.9 kg.

## Abstract

As drone technologies advance, there is an increasing need for structural components that are lightweight, durable, and easily replaceable. Additive manufacturing (AM) with PLA offers a cost-effective solution to improve mechanical performance, especially when enhanced with embedded metal inserts. However, the long-term durability of PLA–metal joints under environmental aging conditions remains underexplored. This study evaluates the mechanical integrity of 3D-printed PLA drone arms produced with reduced infill density with embedded brass inserts. To replicate realistic service conditions, the samples underwent natural aging and five artificial aging protocols involving thermal cycling, humidity, UV/IR exposure, and freeze–thaw cycles. Mechanical performance was assessed through pull-out and tensile strength testing, supported by FTIR spectroscopy, colorimetric, wettability analysis, and finite element modeling. Notably, to our knowledge, wettability analysis has not previously been applied to this type of material, and metal–plastic contact zones have not been tested under such comprehensive aging protocols. Results showed a 70% reduction in pull-out strength under harsh conditions, though the joints remained functional. Numerical modeling confirmed that stress concentration begins on the inner side of the arm. With optimal print settings, the arm can support a 2.31 kg payload (20% confidence), while the metal inserts withstand up to 17.9 kg.