Laser cladding: Why replace components when you can fix them?

What are the options available to a manufacturer or an end user when high-value precision-engineered components, such as molding/forging dies and gas turbine blisks undergo wear or damage? One obvious option is to replace them, which is cost-prohibitive. The other possibility is to try to prolong their life using reliable and proven scientific techniques.

And this is where laser cladding helps.

Laser cladding is a coating technique in which one or several layers of a certain material called clad is deposited onto a substrate, in such a way that a sound interfacial bond is formed, without significant dilution of one into the other. The objective is to obtain an improvement in surface properties, usually corrosion and wear-resistance. This technique is also increasingly being employed in the industry for coating and repairing of tools/dies, turbines and other expensive components with surface damage.

This technique has immense potential in free-form repair/restoration of complex dies and aerospace components which can be a game changer for the precision manufacturing industry. This process can help create additive manufacturing ecosystems by developing autonomous damage-detection based robotic restoration technologies for on-site repair on the shop floor.

Santanu Paul, a researcher with the IITB-Monash Research Academy, is working on a related project titled, 'Laser surface cladding for structural repair' under the supervision of Prof. Ramesh Singh and Prof Wenyi Yan. His project involves numerical modeling as well as experimental analysis of laser cladding technology for thermo-mechanical and metallurgical stress analysis on structures subjected to repair.

"Laser cladding is a promising technique to repair/restore critical structural components in the aerospace and manufacturing industries," says Santanu. "These components are subjected to cyclic thermo-mechanical loads and, hence, prone to fatigue. Consequently, controlling the integrity of the clad in the repair process is of utmost importance. My work is primarily to understand and model the various factors affecting the clad integrity, specifically, for repair applications. We are also attempting to develop strategies for free-form deposition via laser cladding for in-situ repair operations. This work is expected to bridge the technology-deficit in this area by developing science-enabled technology to ensure that the restoration is robust and reliable."

(Top left) Restoration of tool steel used in machining via laser cladding; (top right) infrared image during deposition; (below) temperature distribution as captured by the finite element model: PC: Machine Tools Lab, IIT Bombay

The IITB-Monash Research Academy operates a graduate research program in Mumbai, and is a Joint Venture between the IIT Bombay and Monash University, Melbourne. It fosters research partnerships between Australia and India. Research is conducted by scholars in both countries, whilst studying for a dually-badged PhD from both organizations.

Says Prof Murali Sastry, CEO of the IITB-Monash Research Academy, "Laser cladding is an emerging material processing domain, involving the effective interdisciplinary engagement of laser technology, CAD/CAM, robotics, sensors, controllers, powder metallurgy and machine design. In recent years, it has gained momentum due to the diversity of its potential applications: metallic coatings, high-value mechanical component repairs, rapid prototyping, layered metal deposition and nano-scale manufacturing, highly precise surgical/medical equipment and intricate electronic components. Therefore, the knowledge base generated from the project will help in the production and life enhancement of various high value components."

Apart from the aerospace, automobile, medical and electronic industries, the knowledge base created from the project is expected to benefit the nuclear industry as well.

The expected outcomes from Santanu's project are:

  • To develop a finite element model to simulate the metallurgical and thermo-mechanical aspects of the laser cladding process
  • To design, fabricate and develop associated instrumentation for a laser cladding system to experimentally study the process capability and validate the numerical model developed
  • Applying the validated model to investigate the process/laser parameters on the desired response of laser cladding method to repair structures

Says Prof Sastry in conclusion, "I am excited about the IITB-Monash Research Academy and its potential to make significant contributions to business and society in India and Australia. I am confident that the unique collaboration model that the 'Academy' follows will attract innovation-led industry, top-ranking students and the best researchers to work together to solve grand-challenge problems that need to be solved."

Research scholar: Santanu Paul, IITB-Monash Research Academy

Project title: Laser surface cladding for structural repair

Supervisors: Prof. Ramesh Singh, Prof. Wenyi Yan

Contact details: santanupaul@iitb.ac.in

This story was written by Mr Krishna Warrier based on inputs from the research student and IITB-Monash Research Academy. Copyright IITB-Monash Research Academy.