So some progress has been made from the previous time I posted about my research project. Again, there’s been a lot of machining from my part and I have practically finalized some specimens that are ready for wire EDM (Electrical Discharge Machining). What’s wire EDM?
By looking at this picture, it’s basically a way to cut small notches into different parts or materials by exerting a very high voltage between two electrodes separated by a dielectric liquid. Once the voltage is high enough, current passes through the diodes and cuts the whatever is in between. Sure don’t want to get my fingers between there!
But anyhow, there are 3 of us working on this research project and each of us has a different type of rail with different material properties. We all have been working on the crown of the rail (the contact surface that the wheels make with the rails) and we each have three specimens that are almost ready to be wire EDM-ed. My crown parts look as such:
Cut 2 and Cut 3 are going to look like the three “cubes” on the top. All I need to do for the top cubes is place a smooth surface on each piece because when we perform our Fracture Toughness test, we will need to observe the crack that propagates with each load that is applied to the specimen. It may seem as though this specimen preparation is a very simple task to do, but it takes a lot of time and if you mess up once, well…. It’s REALLY bad. This isn’t a project that you just make up on your own. In my case, Lehigh is essentially a contractor to the Federal Railroad Administration that is running these tests for them to extract the necessary information needed in order to improve that quality of these railroad tracks. Sure we have funding and could always get more rail, but starting all over takes too long and progress needs to be made.
Most of our work is done on a Bridgeport mill where we do most of the precise material cutting and finishing, but we sometimes use the bandsaw to cut large excess material.
This is a typical Bridgeport mill that we use at the student shop in order to do our work. One must be careful when milling. Things such as feed rate, RPM, and material wear on the tool must be noticed at all times so that you can get the best results. Don’t forget about keeping track of how much material you take off! You’ll be toast if you don’t!
More updates to come!