3-D Printing for the Marine Industry
The marine industry in general has been slow to embrace the 3D printing concept. The
use of continuous liquid metal deposition under computer numerical control has created
opportunities to produce complex shapes such as forgings and castings whilst avoiding
the need for expensive tooling and the time delays in fabricating moulds.
Notwithstanding this slow start, development
work at Delft Technical University in 2017 has
led to the production of the world’s first metal
deposited marine propeller.
The majority of published documents on 3-D printing
have been restricted to high precision applications,
particularly in the medical sector. Whilst these
examples illustrate the potential for producing small
complex shapes the process is slow and expensive.
Less well promoted are applications in which large
engineering products using metals have been
produced faster and less costly than using traditional
methods such as casting and forging.
applied where smaller, delicate objects are required.
An example is the production of body implants [Ref
1-3].
The welding version of 3D printing, Wire and Arc
Additive Manufacture (WAAM), is performed by
laying down progressive beads of metal, [Figure
1]. This technique is more suited to the production
of larger and heavier engineering components as
evidenced by the manufacture of marine components
and airframe structures [Ref: 4 – 6].
The Concept Of 3-D Printing
Several methods for 3-D printing using metals
are now in regular use by specialist organisations.
Essentially they involve using a targeted heat source
to melt or sinter metal alloys and progressively build
up a complex three-dimensional shape. A computer
numerical control system, usually a multi-axis robot,
guides the heat source. Solid metal in the form of
wire or powder is fed into and is fused by the heat
source.
One version uses a laser or an electron beam as the
heat source in conjunction with metal powder, Direct
Metal Laser (DMLS) or Electron Beam (DMEBS)
sintering. This powder technique is most effectively
8 TUBE NEWS June 2019
Figure 1. Illustration of the WAAM Process
In terms of applications for WAAM and DMLS/
DMEBS the welding version is most suitable for
heavier and larger products whilst the powder
alternative is best applied where smaller, delicate
objects are required. In other words, welding is
essentially a bulk deposition technique and powder is
a precise and highly controlled process.