By Melanie Lang
Laser metal deposition (LMD) is an emerging technology being adopted to augment, and in some cases replace, traditional methods
for the remanufacturing, laser cladding, and 3-D
printing of metallic parts. It holds the potential to
save manufacturers time and money when applied
in the right situations.
So how does it work? LMD, also known as directed energy deposition (DED), uses a system in which
metallic powders contained in one or more hoppers
are blown through a deposition nozzle and heated
with a laser to produce a metallic bead. The motion
system lays the metallic beads down, layer upon
layer, to build up a part or to add layers of material
to an existing part (see Figure 1).
The process speed, e;iciency, and quality can
be tailored to the requirements for various applications. Tailoring the process is achieved by varying
laser power, bead width, speed of motion, and powder feed rates.
The technology is scalable and can be used to
fabricate or repair parts measured in millimeters to
meters. Furthermore, building parts or structures
with bimetallics and gradient materials, in which
multiple materials are used either in a mixture or
gradually changed from one material to the next
automatically, is being done today. Buildup with
nickel, cobalt, iron, and copper-based metals, as
well as carbide, magnetic, and other materials, is
Machines and Component Integration
A turnkey LMD machine can be used as a stand-alone
device to 3-D print, clad, and remanufacture parts
(see Figure 2). Such a system also can include
a subtractive feature to finish surfaces. Machines
that include an additive and subtractive feature are
known as hybrid machines. Key machine components include a powder delivery nozzle, a powder
feeder, laser and optics, motion system and controller, process chillers, enclosure for process safety,
dust collector, and CAM programming so;ware.
As an alternative to purchasing a turnkey LMD
system, a fabricator can integrate deposition heads,
powder feeders, and other subassemblies into robot cells (see Figure 3) and production lines to enable LMD capability quickly and at a fraction of the
cost of purchasing a turnkey system. For example,
an existing robot can be outfitted with an LMD head,
powder feeder, and laser to 3-D print, clad, and remanufacture metal parts.
A Look at the Applications
LMD technology is gaining traction in the aerospace,
tooling, transportation, and oil and gas sectors because of its scalability and the diverse capabilities
that a single system can provide. Fabricators can use
the technology’s expanded design envelope to create features with complex geometries, which would
be di;icult or impossible to fabricate with traditional methods. In addition, parts that are made with
traditional manufacturing methods can be repaired
or remanufactured (see Figure 4) by adding material to worn or corroded surfaces or new features to
accommodate a design change. Castings and forgings can be modified or repaired without having to
reproduce the entire part. Figure 5 is an example
of laser cladding, and Figure 6 is an example of
How can this production, repairing, and cladding
be so exact? The CAM so;ware takes a CAD model of
the part and generates a toolpath that the machine
A powder nozzle with a coaxially aligned laser deposits
material onto a substrate or previously deposited material.
A turnkey laser metal deposition machine can be used
to 3-D print, clad, and remanufacture parts.
This photo shows a laser metal deposition head integrated into an existing robot cell, which can be a more cost-e;ective way of implementing this additive manufacturing technology than purchasing a stand-alone device.
This remanufacture of a locomotive sha; made of 4140
steel was accomplished using laser metal deposition.
Laser metal deposition was used to clad carbon to this
316L stainless steel helical rack-and-pinion assembly.
The metal additive process was used to create this marine sha; coupler, made of INCONEL® 625.
An overview of
laser metal deposition
This emerging technology
is not just for very large manufacturers