In indirect extrusion process, one can see the hollow ram or die forces against the stationary work-piece which has been backed up the flat end of the upper die. This operation is marked by no relative displacement between the containing die and the billet, so we see there is no friction involved between them, which greatly improves the external surface finish of the finished product. Because the billet moves with the container the frictional forces are eliminated. This leads to the following advantages:
1. A 25 to 30% reduction of friction, which allows for extruding larger billets, increasing speed, and an increased ability to extrude smaller cross-sections.
2. There is less of a tendency for extrusions to crack because there is no heat formed from friction.
3. The container liner will last longer due to less wear.
4. The billet is used more uniformly so extrusion defects and coarse grained peripherals zones are less likely.
However, one has to remove the lower hollow die that has been pierced upwards into the billet regarding extrusion of the part which sometimes gets stuck to the billet part due to certain plastic deformation, also making this process discontinuous. One cannot be able to obtain the longer continuous extruded part with this technique because one is suppose need to design the hollow die of good strength to bear any such bending regarding its lengthier size that is to be pressed upwards all the way into the cavity of the container.