Friction Stir Welding 

Abstract: The objective of this work is to develop a method to detect the creation of discontinuities (e.g., voids) during friction stir welding. Friction stir welding is inherently cost-effective, however, the need for significant weld inspection can make the process cost-prohibitive. A new approach to weld inspection is required – where characterization of weld quality can be obtained in real-time, reducing the need for post-process inspection. 
Funding: National Science Foundation (NSF) 
Co-advisors: Prof. Nicola Ferrier, Prof. Neil Duffie and Prof. Michael Zinn

    FSW of 6061-T6 Aluminum Alloy

Micro End Milling 

Abstract: The goal of the present work is to improve the current understanding of micro tool wear and life during channel milling of tool steel. An additional goal is the creation of procedures and software programs to help automate the analysis of micro tool wear on large quantities of tools. Other materials of interest for micro end milling include: copper, aluminum, titanium, fiber reinforced plastics, and graphite.

Funding: National Science Foundation (NSF) 
Collaborators: Performance Micro Tools

Before and After Milling Edge Mapping 

Pulsed Laser Micro Polishing 

The current pulsed laser micro polishing work is on the melting of surface alloyed metals and metal matrix nanocomposites, focusing on the improvements that can be made to surface topography, microstructure, and mechanical and surface properties through control of material composition and process kinetics. Significant work has also been done on the creation and improvement of micro polishing predictive models and simulations.
Funding: National Science Foundation (NSF) 
Collaborators: LasX Industries. 

 Laser Polished Wisconsin Motion W

Additive- Subtractive Manufacturing 

The goal of this research has two components: (1) quantify the energy consumption in wire-based additive manufacturing (e.g., using a welding torch to deposit material) and compare it to the ubiquitous powder-based methods, and (2) determine the feasibility and outstanding problems in developing a novel closed-loop additive/subtractive manufacturing process.
FundingUW-Madison College of Engineering 

           Manufacturing Process
Embedded Temperature Sensors 

The objective of this work is to fabricate temperature sensors directly onto a commercially available tungsten carbide cutting insert for the purpose of accurately measuring the tool-chip interface temperature during machining. Thin-film thermocouples are fabricated on the rake face of an insert with a multi-cathode sputter deposition system. Aluminum stencils (masks) are made using micro end milling to sputter the 100 um-wide Type-K thermocouple traces. This method enables temperature measurements within micrometers of the cutting interface, and hence can monitor interface temperatures to validate analytical/numerical heat transfer models predicting the tool-chip interface temperature during cryogenic machining.

        Instrumented Cutting Insert

Closed-Loop Control of Friction Stir Welding Temperature

Abstract: The objectives of this research are to use a real-time temperature measurement system developed at the LAMSML in a combined temperature and force closed-loop control system for robotic friction stir welding (FSW) that maintains weld quality under various process disturbances. During FSW, several process parameters and condition variations (thermal constraints, material properties, geometry, etc.) are present. The FSW process can be sensitive to these variations, which are commonly present in a production environment; hence, there is a significant need to control the process to assure high weld quality. Reliable FSW for a wide range of applications will require closed-loop control of certain process parameters.

             Temperature Distribution 

Funding: Department of Mechanical Engineering, College of Engineering, WARF Technology Development, U.S. National Science Foundation, Machine Tool Technology Research Foundation
Co-advisors: Prof. Nicola Ferrier, Prof. Neil Duffie, Prof. Michael Zinn
Collaborators: Chris Smith (Founder and VP-Engineering, Friction Stir Link, Inc.)