Published

In-situ annealing and thermal-morphological evolution during extrusion-based additive manufacturing

Published

Shanto, T. A., Ahmed, R., Patel, P., Zulqernine, M. J., Chen, V., Jain, A., & Taylor, R. M. Journal of Manufacturing Processes, 170, 303–318 (2026).

Experimental setup and thermography for the in-situ annealing study: FLIR IR camera acquiring the gage length section, sample spacing on the build plate, thermal images comparing conventional and modified printheads, and the tensile test — Thermography acquisition, sample spacing, conventional versus modified printhead thermal fields, and the three-way fixed effects model used to separate the factors.

Methodology. A full-factorial design of experiments examined printhead type, print speed, and inter-sample spacing, with modulus of toughness (strain energy) as the primary response. Real-time infrared thermography quantified interfacial thermal history, including welding time above the glass transition temperature. X-ray micro-computed tomography and optical microscopy related internal porosity and fracture behaviour to the measured toughness, and effects were separated by ANOVA.

Findings. The best condition, an annealing printhead at 1200 mm/min with 7.5 mm spacing, held the interface above the glass transition for 16.4 s. Bonding potential reached 387.31 °C·s, roughly 83 times the conventional printhead. Void fraction fell from 14.55% to 5.52%, and fracture moved from smooth interface-dominated separation to cohesive tearing and fibrillation. Toughness rose 68% (53.41 to 90.04 MPa), maximum stress 65%, and elongation at break 59%. ANOVA found a significant printhead-speed interaction and a main effect of spacing, so both deposition kinematics and part layout govern how well annealing works in batch printing.

Graphical abstract in four panels: process window, thermal mechanism, structure and failure, and mechanical response — From process window to mechanical response: the factorial design, the thermal mechanism, the resulting void and fracture structure, and the measured gains.

DOI: 10.1016/j.jmapro.2026.05.005

Evaluation of in-process heating for extrusion printing of tall thin-walled structures

Published

Patel, P., Rahman, M. M., Shanto, T. A., Ahmed, R., Kulkarni, P., Chen, V. C. P., Jain, A., & Taylor, R. M. Progress in Additive Manufacturing (2026).

A design of experiments study on a novel heater block design, relating alignment, temperature, print speed, and material conditioning to the flexural strength and geometric accuracy of tall thin-walled PLA. The best condition reached 51.10 MPa bending strength, a 25% gain, with deformation held within ±2 mm.

DOI: 10.1007/s40964-026-01852-z

Experimental characterization of enhanced fused filament fabrication (FFF) of tall thin-walled structures using polylactic acid (PLA)

Published

Patel, P., Ahmed, R., Shanto, T. A., Jain, A., & Taylor, R. M. The International Journal of Advanced Manufacturing Technology, 139(11–12), 5663–5675 (2025).

In-situ thermal energy applied while printing tall thin-walled PLA structures, assessed by three-point bending alongside geometric deviation, surface roughness, and bonding potential. Bending strength more than doubled while geometric accuracy and surface finish were maintained or improved.

DOI: 10.1007/s00170-025-16171-w

A review of design and fabrication strategies for thermoplastic lightweight thin-walled stiffened shells and lattice structures utilizing fused-filament fabrication (FFF)

Published

Ahmed, R., Dola, I. S., Ahmed, S., Rahman, M. M., Shanto, T. A., & Taylor, R. M. The International Journal of Advanced Manufacturing Technology (2026).

A critical review linking design strategies, Design for Additive Manufacturing, and topology optimization to the manufacturing constraints of thin-walled and lattice FFF structures, closing on AI-driven process control and digital twins as the next directions.

DOI: 10.1007/s00170-026-18078-6

Study the performance of a dynamic wall heat exchanger using computational fluid dynamics

Published

Uddin, M. M., Akhtaruzzaman, R., Shanto, T. A., & Hasan, M. N. European Journal of Engineering and Technology Research, 8(3), 38–42 (2023).

A numerical CFD study of a heat exchanger whose channel wall is deliberately deformed to create a peristaltic effect, disrupting boundary layers without high pumping pressure. Substantial heat transfer was achieved even at minimal applied pressure.

DOI: 10.24018/ejeng.2023.8.3.3043

Under Review

Effects of in-process annealing and programmed interlayer cooling on the tensile performance and interlayer morphology of PLA fabricated by FFF

Under review

Ahmed, R., Shanto, T. A., Raiyan, A. Z., Ahmed, S., Barua, S., Chen, V. C. P., Jain, A., Adnan, A., & Taylor, R. M.

The enhanced printhead evaluated with and without a programmed interlayer cooling pause against a standard printhead, on z-printed PLA. Cooling at 0.46 mm offset reached 53.4 MPa, about 86% of bulk PLA, at 0.885% porosity, by cycling the weld between the glass transition and cold-crystallization temperatures to sustain chain mobility without letting crystallization arrest healing.

In-situ annealing of vertically printed short-carbon-fiber ABS: a process-structure-property study of bonding potential, voids, and z-direction performance

Under review

Shanto, T. A., Rahman, M. M., Barua, S., Ahmed, S., Raiyan, A. Z., Ahmed, R., Jain, A., Adnan, A., & Taylor, R. M.

Methodology. A process-structure-property investigation of in-situ annealing applied to vertically printed short-carbon-fiber ABS. An annealing plate re-heats each deposited layer, sustaining time above the glass transition temperature and raising bonding potential. X-ray μ-CT quantified internal void content across tensile, fracture, and DMA specimen geometries, and SEM fractography identified the failure mode.

Three-panel process-structure-property summary: in-situ thermal annealing schematic, micro-CT void content for standard versus modified specimens, and z-direction property gains with SEM fracture surfaces — Process, structure, and property: the annealing plate raises bonding potential, μ-CT shows the voids closing, and z-direction performance rises as fracture turns cohesive.

Findings. Void content fell in every geometry measured: 4.00% to 0.70% in tensile specimens, 1.49% to 0.60% in fracture specimens, 5.612% to 3.592% in DMA specimens. In the z-direction, tensile strength rose from 16.5 to 22.9 MPa (39%), glassy storage modulus from 0.75 to 1.23 GPa (63%), and Mode-I fracture toughness from 1.20 to 2.29 MPa√m (92%), with a 30% gain in elastic modulus. SEM showed failure shifting from interfacial to cohesive, with fiber pull-out, debonding, and matrix tearing absorbing the extra energy instead of the weld line releasing.

Submitted to Composites Part B: Engineering.

Controlling interlayer bond strength in fused filament fabrication through adaptive in-situ annealing

Under review

Shanto, T. A., Ahmed, R., Patel, P., Barua, S., Dola, I. S., Chen, V., Jain, A., & Taylor, R. M.

Methodology. A coaxial heated plate positioned behind the nozzle gives independent control of annealing plate temperature (APT) and annealing plate height (APH), moving past a fixed thermal setting. Infrared thermography captured interfacial thermal history during vertical printing, tracking welding time against a glass transition of 104.59 °C. X-ray μ-CT quantified void fraction, SEM examined fracture surfaces, and tensile and DMA coupons measured the mechanical response. A thin-walled UAV box-beam served as the structural case study.

Three-panel summary: process control with the coaxial heated plate and thermography, microstructural mechanism showing bonding potential and void reduction, and property improvement with stress-strain curves and SEM fracture surfaces — Independent control of plate temperature and height raises bonding potential 3.8-fold, cuts void fraction roughly threefold, and shifts fracture from adhesive to cohesive.

Experimental setup with FLIR camera and vertically printed specimen, welding time tracking thermograms, and dimensioned drawings of the box beam, DMA coupon and tensile coupon — Experimental setup, welding-time tracking, and the box-beam and coupon geometries. Dimensions in millimetres.

Findings. Adaptive control raised bonding potential 3.8×, from 756.04 to 2855.88 °C·s, and cut void fraction roughly threefold, from 0.658% to 0.206%. Annealed coupons sustained higher stresses across the full strain range, giving modulus +65%, ultimate tensile strength +39%, and toughness +58%. Fracture shifted from interface-controlled adhesive failure to cohesive, bulk-controlled failure. The thin-wall case study gained 55% in flexural strength with improved cross-sectional accuracy, at a modest cost in build height.

Under review at Additive Manufacturing.

Ongoing

Experimental and multiscale numerical investigation of interlayer fracture in standard and in-situ-annealed FFF structures

Ongoing

Shanto, T. A., Ahmed, S., Labanya, F. N., Lin, S., & Taylor, R. M.

Methodology. Two Mode-I fracture geometries are studied experimentally and numerically in parallel: single-edge-notched bend (SENB) coupons, 100 × 20 mm with a machined initial crack, for fracture toughness, and double-cantilever-beam (DCB) coupons, 145 × 20 × 10 mm, for interlayer fracture energy. A preliminary study across standard and in-situ-annealed specimens set the coupon thickness.

SENB and DCB test configurations shown alongside their corresponding finite element meshes — Both fracture geometries are studied experimentally and numerically: SENB for fracture toughness, DCB for interlayer fracture energy.

Preliminary thickness study specimens, dimensioned DCB and SENB coupons, and the fracture toughness test setups — Preliminary thickness study, coupon geometries, and the fracture toughness test setups.

On the numerical side, a representative volume element supplies homogenised solid properties, and cohesive surfaces carry the interlayer damage. DCB and SENB finite element models are then calibrated against the measured load-displacement records.

Cohesive surface and solid material models, representative volume element, DCB and SENB finite element models, and a table of calibrated cohesive-zone parameters for standard and in-situ-annealed material — Calibrated cohesive-zone parameters for standard and in-situ-annealed material, alongside the RVE and the DCB and SENB models they feed.

Findings so far. Calibration separates two effects that a single toughness number would conflate. The annealed material is stiffer, with elastic modulus rising from 1045 to 1485 MPa, and absorbs far more energy before the crack runs, with Mode-I fracture energy rising from 3.63 to 6.45 N/mm. Its normal cohesive strength falls, 36.19 to 29.44 MPa. The interface does not simply become stronger; it deforms more before releasing. That trade produces the measured gains of 84.3% in DCB conditional resistance and 96.2% in SENB total work while arm stiffness stays unchanged, confirming the treatment acts on the interlayer damage process rather than bulk elasticity.

A practical consequence worth stating plainly: most annealed specimens failed the linearity requirement that every standard specimen satisfied. Improved damage tolerance and reduced linear-elastic testability arrive together.

Improving the sealing capacity of FFF ducts for aerospace environmental-control-system applications

Ongoing

Rahman, M. M., Shanto, T. A., Ahmed, R., & Taylor, R. M.

Manuscript in preparation.

Improving the mechanical performance of lightweight PLA for unmanned aerial vehicles

Ongoing

Ahmed, S., Shanto, T. A., Ahmed, R., & Taylor, R. M.

Ongoing research.

Improving the compressive strength of thin-walled stiffened cylindrical structures and characterizing damage using acoustic-emission sensing

Ongoing

Ahmed, R., Zulqernine, M. J., Shanto, T. A., Lin, S., & Taylor, R. M.

Ongoing research.