Figure. 3. Friction Stir Welding of Al to Al. The top surface of the weld can be seen on the left and a tension tested weld sample is on the right.
Welding/Joining Research Activities at Clarkson University
Chair / Professor Daryush Aidun of the Mechanical and Aeronautical Engineering (MAE) Department and his group at Clarkson are carrying out various research activities related to welding/joining of materials. His work includes Friction Stir Welding of Al to Al (Figure 3), Friction Welding of Dissimilar Tubing such as Al to Cu, and the Internal Orbital GMA Welding Process which can be used to coat the interior of less expensive and low corrosion resistance piping with high corrosion resistant alloys (such as coating the interior of A36 steel with 310 stainless steel). In addition, Professors Aidun and Marzocca are working to design a remote controlled welding system for an unmanned aerial vehicle (UAV) to investigate the effect of altitude and maneuvering on the weld solidification and the overall weld quality. Some of Professor Aidun’s projects were initiated from his ME 492/ME 590 Welding Metallurgy course, which is offered every spring semester.
Clarkson University Transfers Its Technology to New York State Industry
Clarkson University's Research Professor Benjamin Dorfman and President of Apex Technologies, LLC, Steve Rohring continue to focus their research efforts on Abrasive Water Jet (AWJ) technology. The Ultra-High Pressure Abrasive Water Jet (AWJ) is the most universal and the fastest growing machine tool worldwide. However, this relatively new technology has not yet reached its full potential. Brittle minerals such as garnet are conventionally used as the media for processing materials. Thousands of tons of garnet are mined yearly from natural mountains for AWJ and almost instantly turned to waste during the processing, which then becomes mountains of waste at landfills. It is basically a ‘use it once then throw it away’ process that has a significant negative impact on energy and resource consumption in NYS which has several large garnet mines.
As a result of their joint work, Dr. Dorfman and Mr. Rohring discovered the supercritical character of the basic physical phenomena underlying the Ultra-High Pressure Abrasive Water Jet. The critical cutting speed itself is the maximum transverse speed at which the water jet carrying the solid particles can penetrate through the subject material, such as an inch-thick steel plate. In mechanical terms, exceeding this critical value would result with a crucial change from the piercing-through mode to the reflection mode of supersonic flux of hard particles.
When the critical cutting speed was precisely measured versus the relative hardness of abrasive micro-particles, a sharp threshold, i.e. secondary critical parameter, or super-critical value was found.
Besides a comparative examination of the AWJ interaction with various materials, including natural single crystals of diamond, the researchers have explored the similarity between micromachining using solid particles and chemical etching of solid materials. This similarity becomes stronger with decreasing particle size, especially with a potential transition to nanomachining.
The newly revealed phenomena, in turn, allows for a shift from mineral abrasives to more durable particles, which is equivalent to a shift from 'Stone Age' to 'Iron Age' in regards to the AWJ. It makes it possible for the AWJ to be converted into a waste-free, tunable, multi-use technology. Moreover, it results in a more durable and precise AWJ cutting tool.
The first patent submitted for this new technology was granted in one month. Professor Benjamin F. Dorfman contributed this patent, and Mr. Steve Rohring contributed new and innovative AWJ equipment to Clarkson University. The U.S. patent 7,108,585, was issued September 19, 2006 for "Multi-Stage Abrasive-Liquid Jet Cutting Head." This multi-stage approach allows the abrasive jet to become a highly productive and efficient tool. APEX Technologies received licensing rights to this patent for the commercial implementation of this technology, and a consortium of several leading companies (working in areas that complement this new technology) was formed.
Also Dr. Dorfman and Mr. Rohring were awarded two grants from NYSTAR for technology transfer from Clarkson University to APEX and its further commercial implementation in New York State industry. In addition, United Materials International (a new company founded in Potsdam as a result of this AWJ research) received a financial award for the recycling and reuse of abrasive materials from Empire State Development. Together these grants total $1,000,000. To make the project completion most effective and economically sound, the professional teams and equipment are now concentrated in the Buffalo area, while certain important characterization work continues to take place at Clarkson University.