Research

Laser welding of zinc-coated steel using optical sensors for in-process weld quality monitoring

Ashish K. Dasgupta, GSRA CLAIM
Jyoti Mazumder, Director CLAIM

Zinc-coated steel is a popular material in automotive body manufacturing owing to its good corrosion resistance, strength and ease of availability. Laser welding is also very popular nowadays because it delivers superior process and part quality. However, laser welding of zinc coated steel is a challenging task due to the low boiling point of zinc, which evaporates violently at the weld interface resulting in undesirable high porosity joints. The problem is more prominent in lap welds which are commonly used in auto-body fabrication. The aim of this research project is to develop a solution for the welding problem along with an optical sensor for monitoring weld quality in real-time. (Back to Top)

PROJECT SPONSOR — NSF I/UCRC (CLPAM)

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SEM image of a laser machined microchannel on nitride coated silicon
SEM image of a laser machined microchannel on
nitride coated silicon

SEM image of simple straight microchannel with semi-circular cross- section shape connected to a wider and deeper reservoir.
SEM image of simple straight microchannel with semi-circular cross-
section shape connected to a wider and deeper reservoir.

One-step Fabrication by Laser
Micro-machining for Micro-fluidics
Vascular Networks

Donghyuck Kam, GSRA CLAIM
Jyoti Mazumder, Director CLAIM

Laser direct writing has proven to be a flexible tool for micromachining with simple and inexpensive operations. A variety of lasers can be used for micromachining, from nanosecond lasers to ultrafast lasers or from IR lasers to UV lasers, depending on the materials to be fabricated and desired applications. Currently, in our group, using a Q-switched Nd:YAG laser with fundamental wavelength, multi-depth, multi-width 3D microstructures on silicon are machined without photolithography-based methods. A femtosecond fiber laser is also used to explore the limit of the resolution and quality for laser machined micro-channels. (Back to Top)

PROJECT SPONSOR — NSF I/UCRC (CLPAM)


Multi-Energy Processing

Joonghan Shin , GSRA CLAIM
Jyoti Mazumder Director CLAIM

This project addresses the scientific issues related to the multi-energy processing of materials. The goal will be to understand the gas-solid phase interactions with multi-energy sources so that materials can be processed at favorable conditions. Our approach to attain the goal is to use multi energy sources including two pulsed beams and electric field to perform different functions and ablations in thin film deposition process. Using this technique, we will develop the process for deposition of novel thin film with excellent properties, enhancement of film growth rate and other applications. (Back to Top)

PROJECT SPONSOR — NSF I/UCRC (CLPAM)

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Rapid Prototyping of Ti-6Al-4V Scaffolds by
Direct Metal Deposition Technology

G. P. Dinda, Postdoctoral Research Fellow CLAIM
Jyoti Mazumder, Director CLAIM

Direct metal deposition (DMD) technology developed at the University of Michigan is a rapid prototyping method which can be used to manufacture near net shape components using powders from their CAD files. Ti-6Al-4V alloy is widely used as an implantable material mainly in the application of orthopedic prostheses because of its high strength, low elastic modulus, excellent corrosion resistance, and superior biocompatibility. The principal focus of this project is to produce ideal Ti-6Al-4V scaffolds (a supporting structure for growing cells and tissues) by DMD technology for bone tissue engineering. (Back to Top)

PROJECT SPONSOR — NSF I/UCRC (CLPAM)


Nano-Crystalline Surfaces for
Improved Combustion

Sean Bulla, GSRA CLAIM
Arvind Atreya, Co-PI
Jyoti Mazumder, Director CLAIM

Current work is being done to stabilize the flame in the laminar combustion process to achieve a uniform surface reaction. Modifications are being made to the central feed cylinder to improve the fluid mechanics and control. Additionally, overhaul modifications are being made to the virtual instrument data acquisition system for our experiment that will reduce the input channels and simplify the calibrations. Design improvements to the fuel/oxidizer delivery system are being incorporated into the experimental setup as well. (Back to Top)

PROJECT SPONSOR — NSF I/UCRC (CLPAM)

Top image: Unstable Flame
Bottom Image: Central Feed Cylinder Exit

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Transport Phenomena during
direct metal deposition

Xiuli He , Postdoctoral Research Fellow CLAIM
Jyoti Mazumder, Director CLAIM

The mass, momentum and solute transportation during direct metal deposition with coaxial powder injection is simulated using a self-consistent three dimensional model, based on the solution of the equations of mass, momentum, energy conservation and solute transport in the liquid pool. The basic physical phenomena, including heat transfer, phase changes, mass addition, fluid flow and interactions between the laser beam and the coaxial powder flow are considered in the model. The level-set method and continuum model are implemented to track the liquid/gas interface and solid/liquid interface, respectively. (Back to Top)

PROJECT SPONSOR — NIST/ATP


Control system for laser materials processing
with Direct Metal Deposition (DMD)

Lijun Song, Postdoctoral Research Fellow CLAIM
Jyoti Mazumder, Director CLAIM

Direct Metal Deposition (DMD) has been successfully applied in complicated part prototyping, repairs and surface modifications, which is which is extremely hard or impossible by other technologies. DMD involves complicated interactions between laser beams, powders, substrates and processing gas environments. Maintaining a stable and uniform melting pool during the process using a closed loop control system is critical to achieve desired dimensional accuracy, surface quality and mechanical properties. The objective of this research is to develop a comprehensive sensing system to monitor the process and a closed-loop control system to stabilize the process. (Back to Top)

PROJECT SPONSOR — NIST/ATP

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