Stiefan Yevhlievskyi

• • Screw-type pellet extruder for granulate (FGF) 3D printing — full development cycle: screw and drive sizing (0.42 kW, 9.11 N·m, design pressure 245 MPa), DEM feed simulation in Ansys Rocky that exposed uneven pellet flow and drove a hopper redesign, CFD thermal audit that brought the feed-zone housing from 180 °C down to < 40 °C with forced-air cooling, and 5-axis CAM programs for machining the screw.

• • Two-stage modular plastic shredder (≤ 5 mm output fraction for recycling into printing feedstock) — concept selection by benchmarking against WEIMA/GRINDEX-class machines, static & dynamic FEA of shafts and bladed discs, casting-based process plan with 89.5% material utilization and CNC programs for a Y-axis turning centre.

• • Commissioned CFD study of a patented VAWT rotor — parametric Ansys Fluent comparison (8 linked cases) of the patented slotted blade vs a smooth profile, plus a 954k-cell full-rotor transient in Flow Simulation; delivered drag data and a clear cost-vs-performance verdict to the client.

• • Confidential defense-sector project (NDA) — drivetrain and protective-structure redesign for a remotely operated platform: drive efficiency raised 70% → 96%, transmitted impulse loads damped 8.6 kN → 0.4 kN, multi-layer composite protection ≈ 11× lighter than the steel equivalent; kinematics verified in SolidWorks Motion. Details available in interview within NDA limits.

• • Developed a complete mass-production process for a gray cast-iron "bearing cap" component.

• • Justified shell-mould casting that raised the material-utilisation coefficient by 93% and projected annual savings of over 950,000 UAH.

• • Designed a custom drilling jig holding a 0.4 mm positional tolerance and wrote the G-code for the CNC turning operation (FANUC).