On demand production of eductors for naval systems

On-Demand Production of Eductors for Naval Systems

This entry continues Meltio's defence spare parts series, highlighting the redesign and additive manufacturing of an eductor, a fluid-pumping component often used in naval systems.

Eductors: the hidden workhorses of naval engineering

Eductors exploit the Venturi effect to move secondary fluids by creating low-pressure zones in high-speed primary flows. They operate without any moving parts or motors, making them simple, durable, and ideal for constrained systems. They also come with two challenges:

• High wear and difficult to inspect. This makes preventive maintenance and replacements difficult to time.
• Usually made in Cu-based alloys. This involves long lead times and high costs for one-off units.

Meltio's additive approach

Using its DED system, Meltio successfully printed an eductor in 316LSi stainless steel, replacing the need for casting. The part was printed in four distinct modules to ensure both printability and post-processing compatibility:

Main body (46h 40min).
Printed with planar layers and tangent perimeters. The robot's motion was optimised to avoid collisions, using a 35° cone limitation.

Top fixture (8h).
Radial strategy with linear infill. Requires a drilled side duct.

Suction duct (3h).
Built with a non-planar strategy to minimise supports and improve surface finish.

Side connection.
Printed on the Meltio M600 and later welded to the main assembly. This could evolve into a threaded fixture to simplify final assembly.

All segments were designed using Meltio Space, and the build followed a robust parameter set: 1 kW laser, 10 mm/s feed rate and 15 L/min argon shielding.

From legacy replica to AM-first design

Two design iterations were produced:

• The first closely replicated the legacy casting, simplifying validation and testing.
• The second was redesigned for additive manufacturing, with improved printability and machinability.

The redesign included:

• Optimised wall thickness.
• Elimination of overhangs.
• Integrated fixturing walls for CNC setup.
• A circular base to streamline multi-step printing.
• Drop-shaped holes for faster post-processing.

At a glance

• System: Meltio Engine for Robot integration
• Sector: Naval
• Material: Stainless Steel 316LSi
• Printing time: 58h

Strategic advantages for defence

With Meltio, digitally storing designs and manufacturing them on demand is a game-changer for defence readiness. Eductors, despite being niche components, become resilient to supply chain disruptions.

No moulds. No waiting. Just functional parts, printed anywhere, from a naval base to a mobile AM unit.

This case study was originally published by Meltio as On demand production of eductors for naval systems. Reproduced here with credit to Meltio.