Challenges in the energy, environmental, and health sectors present a growing need for flexible and scalable micro-machining processes for applications such as textured surfaces for tissue adhesion and anti-bio-fouling, reduced wear in tooling and engine systems, and functional surfaces for biomedical devices such as needles and implants. This award funds research on a novel micro-machining process that addresses several existing challenges, namely limitations in the machinability of materials, patterning large areas at economically feasible material removal rates, and generating micro-features of different sizes and shapes. A fully realized magnetically-assisted laser induced plasma micro-machining process will be capable of fast and direct generation of micro-features with controlled geometrical characteristics.

In magnetically-assisted laser-induced plasma micro-machining, picosecond laser pulses induce a plasma plume within a liquid dielectric. The plasma plume removes material from the workpiece surface by a combination of thermal vaporization and mechanical erosion to create machined features with desired geometry. This project aims to advance processing capabilities in terms of machining rate and precision by utilizing the external magnetic field's influence on the plasma plume through two mechanisms: (1) by increasing its energy density, leading to increased material removal rates; and (2) by modifying its shape, leading to the nearly direct creation of desired micro-feature geometries. The research objective is to understand the interaction between the electromagnetic and thermo-mechanical mechanisms of the process, i.e., interactions between the laser, dielectric, plasma, magnetic field and workpiece material. Methods to achieve this objective include simulations using magneto-hydrodynamic, particle-in-cell and finite element analysis methods to determine the outcomes of each interaction. Experiments with a wide variety of materials, including titanium alloys, silicon, polymers, and transparent, brittle and reflective materials such as glass, will be conducted using a picosecond laser system with a 532 nm wavelength, a computer-controlled array of electromagnets, and focus variation-based metrology. Experimental results will be compared with simulation results in terms of the depth and shape of the generated features and material removal rate.

Project Start
Project End
Budget Start
2016-06-01
Budget End
2021-05-31
Support Year
Fiscal Year
2015
Total Cost
$300,000
Indirect Cost
Name
Northwestern University at Chicago
Department
Type
DUNS #
City
Chicago
State
IL
Country
United States
Zip Code
60611