Rogelio Herrera

I am pursuing a PhD in Mechanical Engineering. Thesis subject of “Quantifying the mechanical properties of friction surfaced solid-state metallic bonds”. The solid-state bonds in question are produced using a friction surfacing process. Using a 3-axis CNC machine, a metal a rod is spun at a high rotation per minute (rpm), similar to a end mill or a drill bit. The metal rod is then plunged/pushed into the a metal substrate, a metal plate. The rod then moves along the surface of the metal substrate, leaving a cladding or deposit of metal that originated from the metal rod. Depending on the rpms, forces, the feed rate (the movement across the metal substrate), metal types, size of the rod, and the rate the metal rod is pushed down into the substrate will determine the metal cladding layer height and width of the deposition. For the process that is used in our lab, the cladding height will range of approximately o.5 mm up to 3+ mm. I am looking to find a way to test the bond strength of this cladding to the substrate, testing its tensile strength at the interface. Due to the small cladding layer, standard mechanical and material testing methods cannot be used for test samples, dog bones, that can be made from friction surfaced samples. Solid-state welds are one of the oldest metal manufacturing methods. Solid-state welding is a common process used in blacksmithing to bond metals together.

I have a broad range of engineering experience and “hobbies”. I have a strong background in finite element analysis using Ansys, with experience modeling static structural, linear and non-linear elastic, modal and harmonic, transient structural, and explicit dynamic systems. I have extensive experience in traditional metal and composite material machining processes that range from manual milling and lathes, to learning and operating our labs Mori Seiki NT1000W Multi-Axis Turning Center. I’m versed in Esprit CAM (Computer Aided Machining) and Mastercam CAM software. I have extensive experience in computer aided design using SolidWorks. I have an extensive background using B&R’s Automation Studio for the coding and operation of automated process and machines. I machine, weld, design parts, build FEA models, and blacksmith for my own enjoyment at home. My interest in engineering developed from following the materials used, designs, and manufacturing processes of road bikes used for racing and that I ride.

I am an engineer and a PhD student because I enjoy taking a concept for a product, producing a design, analyzing the design, not programming the controls, and building prototypes. I enjoy teaching engineering students how to design and build prototypes. Prior to my engineering education, I was a City of Madison Police Officer, Field Training Officer (I trained new police officer in patrol), Special Events Team member and Grenadier. I have extensive training in chemical munitions, biological/mass-casualty response and prevention,  hardening of public spaces and buildings to prevent and respond to terrorist attacks, and I was an armorer. I was a police officer for 10 years, having to retire due to a in-the-line of duty minor injury. Prior and during my time as a police officer, I was/am a classically trained cellist, starting the cello at the age of five years old. Through policing, I have met and worked with more people then I can remember, allowing me to interact with people of different backgrounds, experience, knowledge, and abilities. I can talk to and give presentations to large groups very easily.

From policing and my music training, I have extensive experience teaching and training students and coworkers. I have found that not only do I have the ability to teach and train people in various subjects and skills (from metal manufacturing processes, weapons and tactics, music, stringed instruments, to very technical subjects involving engineering concepts, programming, math, and analysis) but I enjoy teaching most subjects, not economics because I’m an engineer.

My biggest talent and skill is to annoy my wife and child, which was only enhanced by my ability to talk ad nauseum about metals, carbon composites, and engineering subjects in general. We travel often, and my wife is has resigned herself to waiting while I take too many pictures of iron work, armor, and various edged weapons made by blacksmithing.

If I or our lab can be of assistance in manufacturing processes, multi-material manufacturing, multi-axis machining, or engineering in general, feel free to contact us.