The basic principle behind all welding processes is to produce a molten pool in the locality of the joint being formed and to add a filler material (if required) as the materials from either side of the joint run into one another forming a re-enforced joint.
The extrusion process applies to a variety of processes that involve confining a material in a container and applying a force to push the material through an orifice to produce a required shape.
Single point cutting using standard tools and equipment is a good option for the production of small batches and 1 off items such as prototypes.
Squeeze casting uses an accurately measured quantity of molten metal which is poured into a mould using a launder.
The selection of a manufacturing process is done very much on the basis of a manufacturer choosing the process that best suits his needs. Consideration must be given to a number of factors before deciding.