RESEARCH

Laser, MEMS, and nanoprocessing are emerging as increasingly important technologies to many of today’s industries. New developments and applications are rapidly introduced. The successful application and utilization requires a thorough understanding of the processes involved for which the state-of-the-art laboratory is ideally equipped. A wide range of research spanning from laser machining of metals to nanofabrication of medical devices has been conducted over the past decade.

CURRENT/RECENT RESEARCH PROJECTS

• Femtosecond Laser Machining of Diamond, National Science Foundation

  A novel femtosecond (10-15 sec) pulsed laser is used to develop a high precision, contamination-free, time efficient machining technique for diamond and difficult-to-machine ceramics. A fundamental understanding of femtosecond laser-diamond interactions will be developed using molecular dynamics simulation methods.

   

• Laser Manufacturing Process for the Production of High Efficiency Materials for Transformer Cores, Asea Brown Boveri, Inc., National Science Foundation, CATD, and EPRC

  This project, supported by NSF, Industry, EPRC, and CATD, involves a study of incorporating a rapid, fiberoptics laser process to the manufacturing line of transformer core materials. The laser process produces the favorable stresses that assist in refining the magnetic domains required to reduce the core loss and thereby improve the efficiency. A finite element model is being utilized to predict the stresses developed during laser processing. This environmentally conscious manufacturing is an excellent alternative to the currently considered chemical thinning methods.

   

• Advanced Lasers for Thin Sheet Metal Welding, 1995-1996, U.S. Air Force/ Metals Tech Industries, Inc.

  The objective of this research is to study the suitability of advanced lasers for thin sheet metal welding. The advanced lasers include diode, iodine/oxygen, and HF which were recently made available in high powers. In addition to the study of the process, the complete system design for welding large (5’ x 5’) sheets will be made. This project has direct applications to Metal Tech in terms of gasket and other sheet metal fabrication.

   

• Nanostructure Fabrication of Medical and MEMS Devices Using Ultrafast Lasers and Non-linear Optics, National Science Foundation

  This award supports research in the development of an emerging and exciting ultrafast laser technology for the nanofabrication of medical and MEMS devices, in addition to providing funds for acquiring a versatile ultrafast Ti:Sapphire laser system. The transmission of the short-pulsed beam through the non-linear optics will create self-focusing capabilities, facilitating not only the nanometer size cutting, but also the taper-free feature.  The technique offers the possibility of ablating all the material within the nanometer focal region before any significant heat conduction or mass flow takes place, thus enabling precise fabrication with little or no collateral thermal damage.

   

• Femtosecond Pulsed Laser Deposition of Superconducting Oxides, Department of Energy

  Ultrashort pulsed, energetic laser ablation is used to prepare and characterize thin films of novel and complex material systems used in superconductors. Preliminary research on 123 superconductors indicates that femtosecond laser can deposit films that are superior to those produced by nanosecond laser in terms of film smoothness, substrate adhesion, and a large degree of epitaxial orientation.

   

• Functionally Gradient Permanent Magnets by Powder Processing and Pulsed Laser Deposition, Honda and Department of Energy

  Transportation and manufacturing systems employ more than a billion electric motors and generators in sizes ranging from a few ounces to hundreds of tons. The size and weight of these devices depends upon the energy product of the permanent magnets used in their construction. This work investigates a novel processing method that combined powder processing (PP) and pulsed laser deposition (PLD) to produce a graded composition microstructure in Nd₂Fe₁₄B-type magnets and thereby improve the energy product at high-temperatures. Each grain within these functionally graded magnets would have a Dy₂Fe₁₀Co₄B outer layer epitaxially bonded to a Nd₂Fe₁₀Co₄B core.

   

• Laser Coating of Carbon-Carbon Composites for Oxidation Resistance, National Aeronautics and Space Administration

  Carbon-carbon composites used in space shuttle and gas turbine engines require an oxidation protection system to nullify the deleterious effects of air and oxygen and to enhance the usability of these composites in extreme operating conditions. In this work, a new method namely laser-induced chemical decomposition technique is used to apply SiC/Iridium coatings and results are compared with the currently used pack cementation and CVD methods.

   

• Rapid Prototyping of Nanocrystalline Powders for Die-casting Dies and Mold Inserts using Laser Cladding

  Rapid fabrication of dies and molds through a CO2 laser cladding is performed to determine the optimal process parameters and role of nanocrystalline powders on the density, microstructure, and performance of dies used in die-casting and infection molding.

   

• Nanocrystalline, Ultrahard Boride Thin Films by Ultrafast Pulsed Laser Deposition for MEMS and Tooling Applications

  Nanocrystalline AlMgB₁₄ containing 5 to 30 mol% additives are the new, second hardest materials on earth. These ultra-hard boride materials, recently discovered by the scientists of Ames Laboratory, exhibit hardness comparable to or slightly higher than ultra-hard borides with predictability and reproducibility. Research will focus on the development of a novel Ti:Sapphire femtosecond (fs) PLD technique for preparing a family of ultra-hard boride thin films on silicon and cemented carbide substrates for MEMS and hard turning applications respectively.

   

• Development of a Virtual Reality Laser Training (VRLT) Program for Health Care Professionals

  The use of medical lasers in surgical procedures has grown significantly in recent years because they are often safer, faster, less painful and less invasive than alternative medical procedures. In this work, we are developing the virtual reality (VR) as a training tool for learning the safety, operating, and surgical procedures of lasers. VR training will offer hours of self-didactic instruction, a chance to use the laser on inanimate objects, and time with a virtual environment (VE) preceptor. The scope is limited to developing a VRLT program for training specifically in laser skin resurfacing (LSR). Future research will consider vision correction, dentistry, cardiovascular applications, GI/general surgery, optical diagnostics, photodynamic therapy, and orthopedic surgery.

   

PREVIOUS RESEARCH

Laser Machining

The projects listed below dealt with several innovative methods of laser machining that include dual-beam cutting, small hole drilling under nonlinear liquid mediums, chemical assisted laser cutting, egg shell cutting and drilling, design and fabrication of an off-axial gas-jet, paint removal, and ceramic machining.

• Laser Micromachining of Polymers Using Excimer Lasers
• Development of Advanced Laser Cutting Techniques
• Laser Chemical Machining of Metals, Ceramics, and Composites
• Laser Cutting and Drilling of Egg Shells
• Development of a Laser Manufacturing Process for Stripping of Paint Coatings
• Laser Milling, Polishing, and Turning of Ceramics
• Laser Drilling of Holes using Nonlinear Liquid Mediums
• Combustion Assisted Laser Cutting of Difficult-to-Machine Materials
• A Thermochemical Approach to Laser Cutting of Thick Metallic Solids
• Nd:YAG Laser for Research in Manufacturing Processes
• High Power CO2 laser for Research in Wear and Manufacturing of Materials
• Numerical Simulation of Reactive Gas-Assisted Laser Cutting of Thick Metals

Laser Welding

The projects listed below focused on the weldability, microstructure, and comparison with arc welding in terms of mechanical properties

• Laser Welding of 2090 Al-Li Alloy
• Laser Weldability of Nickel Aluminides
• Laser Welding of Oxide Dispersion Strengthened MA 754 Alloy

Laser Heat Treatment and Surface Processing

These projects dealt with a variety of surface processing in improving the performance of components and synthesizing advanced materials. All these projects are collaborative efforts between the university and industry.

• Laser Chemical Vapor Deposition of Diamond and Fluorinated Diamond for Electronics and Tribology Applications
• Laser Ablation Synthesis of Cubic Boron Nitride
• Development of Metallic Glass Refractory Coatings on Composites Using Lasers
• Laser Melt Texture Growth of 123 Superconductor
• Excimer Laser for Research in Materials Processing
• Laser Cladding of Thermal Barrier Coatings
• Development of High Hardness Cutting Tools by Laser Surface Processing
• Fatigue and Wear Behavior of Laser Transformation Hardened Cast Irons
• Laser Heat Treatment of Valve and Pump Castings
• 1.5 kW CO2 Laser for Research in Heat Treatment
• Laser Surface Coating of Titanium