Source-linked AI summary
Extending high value components performances with Additive Manufacturing: application to naval applications
Matthieu Rauch, Gatien Pechet, Jean Yves Hascoet, Guillaume Ruckert
TL;DR
The paper examines how additive manufacturing can enhance high-value naval components through geometries inaccessible to conventional manufacturing. It develops a 1.5 m hollow propeller-blade demonstrator using WAAM and an 8-dof robotic cell, achieving the intended mass reduction with promising dimensional accuracy.
Problem
Conventional manufacturing constrains complex propeller geometries, motivating additive manufacturing solutions that can reduce weight while preserving or improving performance.
Method
The study uses WAAM with an 8-dof robotic cell to manufacture a hollow duplex-stainless-steel propeller-blade demonstrator and characterize its material and geometric properties.
Results
The demonstrator achieved a 49% mass reduction compared with a full blade, while 3D inspection found maximal deviation below +/- 1%.
Takeaways & Limitations
WAAM and multiple-axis robotic redundancies provide a viable route to manufacturing complex hollow propeller geometries for high-value marine components.
Takeaways & Limitations
The earlier 6-dof manufacturing strategy required multiple setups, limited cavity size and mass reduction to 34%, and could not manufacture monobloc propellers.
Abstract
from arXiv · showhide
Additive Manufacturing (AM), consists of depositing material in successive layers to obtain the desired part. The parts produced by AM can thus adopt geometries inaccessible by conventional manufacturing means, for example hollow or lattice structures which considerably reduce their weight while keeping or even improving their mechanical properties. Among the many existing processes, Wire Arc Additive Manufacturing (WAAM) is particularly well suited to the manufacture of large metallic parts. It is characterized by a supply of heat in the form of an electric arc (produced by a welding generator) and a supply of material in the form of wire. This paper will discuss the impact of additive manufacturing to enhance the performances of high value components, based on naval application: the manufacturing of a hollow propeller blade demonstrator of 1.5 m high realized in the laboratory.
Evaluation of AM interest
AM enables a hollow propeller-blade design, process-adapted geometries, and controlled deposited-material properties for naval applications.
- Evaluation of AM interest: Hollow blade geometry leaves an internal cavity based on fluid- and structural-mechanics requirements.The design targets reduced noise and vibration and improved hydrodynamic efficiency through reduced cavitation.
- Evaluation of AM interest: DFAM adds local thickness at the blade’s leading edge to prevent molten-pool collapse during WAAM.The added thickness supplies thermal inertia and is later removed by postproduction machining.
- Evaluation of AM interest: Heat-input control, including dwell time, helps avoid harmful metallographic phases and meet material specifications.This illustrates AM’s ability to control local manufactured-component characteristics.
- Evaluation of AM interest: Duplex stainless-steel test blocks exceeded mechanical requirements and showed fine austeno-ferritic microstructure without critical defects.These results validated duplex stainless steel with WAAM for manufacturing a hollow propeller blade.
Interest multiple axial redundancies on the equipment
An 8-DOF robotic cell extends WAAM motion flexibility and enables controlled torch orientation for complex hollow-blade geometries.
- Interest multiple axial redundancies on the equipment: A prior 6-DOF demonstrator limited cavity size to 34% mass reduction versus an expected 50% and required multiple setups.Its strategy also could not be applied to monobloc propellers because the part could not be rotated for other blades.
- Interest multiple axial redundancies on the equipment: An 8-DOF cell combines a 6-axis robot with a 2-axis positioner, increasing configurations but requiring collision and singularity management.Toolpath simulation is essential for anticipating robot behavior.
- Interest multiple axial redundancies on the equipment: The additional positioner changes torch orientation to keep the melting pool controlled relative to gravity at steep blade regions.This compensates the trailing-edge slope and avoids melt-pool collapse.
- Interest multiple axial redundancies on the equipment: Multiple axial redundancies build the hollow blade in one setup and better support manufacturing a complete propeller.The positioner permits rotation of the part for realizing other blades.
Result analysis: Evaluation of the propeller manufactured
The 8-DOF robotic cell produced a hollow blade with improved cavity closure and close agreement with the CAD geometry.
- Result analysis: Evaluation of the propeller manufactured: 49% mass reduction compared to a full blade met the design expectation for the completed hollow blade.The 8-DOF robotic cell improved cavity closing during fabrication.
- Result analysis: Evaluation of the propeller manufactured: The CAD-to-scan comparison showed a maximal deviation below +/- 1%.The offset was attributed to positioner accuracy, calibration range, and thermal behavior; finishing machining remains necessary for the final functional shape.
- Result analysis: Evaluation of the propeller manufactured: The completed demonstrator was evaluated by scanning the blade and support with a handheld laser scanner.The scan was compared with the CAD model in Fig. 5.
Conclusions
The study shows that WAAM and multi-axial toolpaths can extend high-value component performance through process-adapted hollow designs.
- Conclusions: WAAM enabled a hollow propeller-blade concept while providing control of deposited-material properties and adaptive toolpath parameters.The conclusion concerns a marine propeller-blade use case.
- Conclusions: An 8-DOF robotic cell enabled complex overhanging areas to be manufactured in one setup with the expected mass reduction.The approach required complex toolpath programming and used multi-axial toolpaths.