PLA-Based Additive Manufacturing and Thermal Aging Analysis of UAV Airfoil Profiles
TÜBİTAK 1002-A research project evaluating dimensional deformation and aerodynamic efficiency loss in FDM-printed NACA profiles after controlled thermal exposure
01 Problem & Context
FDM-printed PLA components used in UAV airframes deform under thermal loads encountered during field storage and operation (enclosed compartments, direct sun exposure). No standardized criterion exists to determine when a thermally aged PLA wing section should be replaced rather than continued in service. The study addresses this gap by establishing a quantitative relationship between thermal exposure, dimensional deviation, and aerodynamic efficiency loss — producing a binary go/no-go maintenance threshold directly applicable to UAV maintenance workflows.
02 Objectives & Constraints
- — Compare chord and span dimensional deformation across NACA 0012, 2412, and 4412 profiles at 50±5°C for 30, 60, 120, and 240-minute thermal exposure durations
- — Quantify the effect of two infill topologies (Grid vs. Tri-hex) at 40% density on post-thermal dimensional stability and mechanical behavior
- — Establish the relationship between measured dimensional deviation and aerodynamic efficiency loss (CL/CD ratio)
- — Define a binary maintenance decision rule: CL/CD deviation > 7% relative to as-printed baseline → wing section rejected; ≤ 7% → continued service
03 Process
Process
Research Context
This project is proposed under the TÜBİTAK 1002-A Quick Support Program, which funds applied research with short development cycles. The motivation is the increasing use of FDM-printed PLA components in low-cost UAV airframes, where operational thermal conditions — enclosed vehicle compartments, rooftop storage, direct sun exposure at field sites — can induce dimensional changes that degrade aerodynamic performance without visible structural damage.
The research question: at what level of thermal-induced dimensional deviation does a FDM-printed PLA wing section cross the threshold from serviceable to unserviceable?
Specimen Design and Print Protocol
Three NACA profiles were selected to represent the range of UAV wing geometry families:
- NACA 0012 — symmetric, used in stabilizer and control surfaces
- NACA 2412 — lightly cambered, general-purpose lift surface
- NACA 4412 — higher camber, lift-optimized configurations
Full wing geometries were sourced from GrabCAD3D and prepared for FDM output in SolidWorks. Print parameters are standardized across all specimens: 40% infill density, two topology variants — Grid (rectilinear cross-hatch) and Tri-hex (triangulated hexagonal). All specimens are produced on the Bambu Lab A1 Combo using standard PLA.
Thermal Exposure Protocol
Specimens are thermally aged at 50±5°C, a temperature selected to represent a realistic upper boundary for UAV field storage (enclosed vehicle compartment, moderate solar exposure). Four durations are tested: 30, 60, 120, and 240 minutes, producing a time-series degradation profile for each profile × infill combination.
Measurement and Aerodynamic Analysis
Post-exposure dimensional deviations are recorded at standardized chord and span measurement positions using calipers, referenced against pre-exposure baseline measurements taken immediately after printing. Deformed geometries are analyzed computationally using ANSYS Fluent to extract CL/CD ratios and quantify aerodynamic efficiency change relative to the as-printed baseline.
Mechanical integrity is assessed in parallel through bending tests (out-of-plane loading on the wing section) and T-bone tensile tests (inter-layer adhesion under tensile load), providing a structural complement to the aerodynamic data.
Decision Rule Development
The primary deliverable is a binary maintenance threshold: if the post-thermal CL/CD deviation exceeds 7% relative to the as-printed baseline, the wing section is classified as unserviceable and requires replacement. Below this threshold, continued service is permitted. The 7% threshold is based on aerodynamic sensitivity analysis of the three profile families and represents the target to be validated by the experimental data.
This framing — converting continuous degradation data into a go/no-go field criterion — is the operational output that bridges the research to UAV maintenance practice.
04 Challenges & Solutions
Controlling dimensional accuracy across three NACA profiles with significantly different camber geometries on a single FDM platform
Standardized print orientation and infill parameters across all specimens; GrabCAD3D source geometries used as fixed reference baselines for pre- and post-thermal deviation measurement, isolating thermal effect from print-to-print variability
Isolating the aerodynamic consequence of dimensional deviation from other print-induced variability (surface roughness, layer adhesion quality)
Structured the test matrix around thermal exposure duration as the single independent variable; identical print settings across all specimens minimize confounding factors, and bending/T-bone tensile tests separately characterize mechanical integrity change
05 Results & Outputs
- ✓ Research proposal submitted under TÜBİTAK 1002-A program; methodology, test matrix, and decision framework defined
- ✓ Profile geometries (NACA 0012, 2412, 4412) sourced and prepared for FDM production
- ✓ Print parameter matrix specified: 2 infill topologies × 3 profiles × 4 thermal exposure durations
06 Measurable Impact
Thermal exposure conditions: 50±5°C at 30 / 60 / 120 / 240 min durations
Infill configurations: Grid and Tri-hex at 40% density
Maintenance decision threshold (target output): CL/CD deviation > 7% → wing rejection
07 Lessons Learned
- → Converting a continuous material degradation mechanism (thermal creep in PLA) into a binary maintenance decision required reducing the full experimental dataset to a single actionable threshold — this translation was the core design challenge of the research framing, not just the physical testing
- → Profile geometry selection (symmetric 0012 vs. cambered 2412/4412) meaningfully affects both FDM print complexity and the sensitivity of aerodynamic performance to dimensional deviation; symmetric and cambered profiles must be treated as distinct test conditions rather than a uniform specimen set