Almir Heralić, Anna-Karin Christiansson, Mattias Ottosson, University West

Almir Heralić, University West

Laser Metal Deposition: Supporting technology for manufacture of complex structures in the aero industry

Almir Heralić, Anna-Karin Christiansson, Mattias Ottosson, University West

Torbjörn Norlander, Peter Jonsson, Börje Nordin, Volvo Aero

FLUD - VINNOVA

Laser Metal Deposition


What is Metal Deposition?

Metal deposition is an additiveprocess that joins metal beads

• side-by-side

• layer-by-layer

according to predefined paths.

Beads are formed by melting metal wire (or powder) using a heat source, e.g. a laser or other welding equipment







Metal deposition example

Deposition movie



Close-up view of the melt pool



Some applications

Prototyping

New manufacturing – Fabrication– Shape modification

High-value component repair or modification

…



Fabrication

Welding, forging, machining, casting, metal deposition, sheet metal forming



Fabrication – example Ti-6Al-4V

sheet metal + welding

LMD (weld prep)LMD

machining + welding

casting



Standard welding cell rather than specially

made high-cost equipment

Laser heat source implies low heat input

Metal wire instead of powder

A 6-axis robot offers flexibility

Reduction in waste material and energy

Potential for cost efficiency and shorter lead

times

Process advantages - LMD



Demanding from a sensor and

measurement point of view

The process is not fully understood

The use of wire imposes certain limitations

...

Identified difficulties



Process related difficulties

Several process parameters need careful tuning to obtain a stable process.

For example:

•Laser power/wire speed ratio

•Wire tip position relative the weld pool

•Estimated bead height



Process related difficulties

Incorrect process parameters usually lead to:

• formation of droplets

gives irregular deposition

• insufficient melting of the wire

can lead to lack of fusion



Laser power/wire speed vs. weld quality



Results – manual control

Common errors without feedback

Manual control with feedback



Automation of LMD



Welding tool - sensor configuration



Feedforward height control



PI-control of bead width



Results

• Developed an LMD cell with a sensor- and measurement system

• Stable process ensured, manual/automatic control

• Good dimensional accuracy

• Reduced risk for lack of fusion defects



University West / industrial partners:

Increase the knowledge about the LMD process, e.g.

temperature influence on the geometrical and mechanical

properties of the deposited parts. Develop Off-Line

Programming tools.

Manufacturing industry:

Work towards industrialization of the LMD process

Future work

Almir Heralić, Anna-Karin Christiansson, Mattias Ottosson, University West

Documents