Through designing and virtual testing of our mandrel extrusion model we have gathered information that has allowed us to reach certain realizations about the extrusion process.
The first of these involves the size of the billet used in the process. As discussed in the previous section the extrusion force scales exponentially with the diameter. This presents one of the main limiting factors for the extrusion process since the force required grows so large it is extremely difficult and expensive to build larger and larger machines. With any manufacturing machine, maximizing the volume you can produce is going to lower the cost, however, with an extrusion machine you run into a wall at a certain size billet that becomes too difficult to extrude. Because our flow stress is small, the extrusion force required is relatively low, but using a larger diameter would require a significantly more powerful press and increasing the cost of this project.
The next point we arrived at through this project was also involved in a similar area of billet and extrusion machine size. As mentioned before, our mandrel extrusion machine is rather small; however, this is because we were working with plasticine, an extremely formable material. Since most of the materials that will be extruded are much stronger metals, this presents another limiting factor for the extrusion process. Extruding a material such as aluminum with a high flow stress will require an immense force driven by a much larger hydraulic force.
The last major conclusion we drew when designing our mandrel extrusion model was the difficulty of having a high safety factor with these large machines. As discussed throughout this section, the extrusion force needs to be incredibly high to push the billet through the die. Since this force is so high, having a high safety factor for the container housing the billet becomes increasingly difficult the larger the billet becomes.
Designing this mandrel extrusion model allowed us to not only understand the challenges associated with our particular model but also the problems and challenges that arise when working with much larger and more powerful machines.