Sphere

Sphere

The sphere is projectile of the experiment. This one of the simplest pieces of the experiment and its creation will be discussed in the following section.

Product Scope

The spheres will be the test specimen of this test apparatus. They will be under the barrel dimension of the .50 caliber gun. The spheres will be made out of oxygen free copper. The spheres will undergo some sort of heat treatment. This is the actual reason for the test itself. The test will be able to discriminate between to small changes in the microstructure, if any.

Manufacturing the Sphere

The following section discusses the process and problems encountered during the acquiring of the sphere component.

Process

The sphere needed to be spherical with a diameter of 7 mm. The diameter was exactly the same size as the Dr. Gray Dynamic Tensile Test. The process for machining was using a radius gauge on a lathe in order to crate a sphere from a rod. The flat on the back side did not matter because the part is going to be largely deformed during the extrusion portion of the test. The part was going to be made out of oxygen free copper and then needed to fit snugly inside the sabots (which had already been machined.

Problems

One of main problems, with several components, the team experienced was the inability to access the funds given to school for the project. The spheres were supposed to be made from oxygen free copper but the team was unable to purchase the copper to have it machined.

The second problem that was encountered concerned the local machine shops (that were doing the work for the project without charge). They informed us that the sphere of that size would be difficult for them to machine. Although spheres are not complex parts to machine, the smaller diameter leads to the sphere becoming ovular and the small section of the rod that holds onto the sphere while machining it. The team was unsure of the requirement of how spherical the specimen needed to be since it was not cited inside the test that was being emulated.

The sponsor ended up providing the spheres created by the machine shop on site at Eglin Air Force Base. The team found a company that could create the spheres as perfect spheres but needed a minimum order of 1000 to produce them. This option was not utilized because the sponsor did not see the need for so many spheres.