The question as to which metal cutting technology is the most sensible has been going on for years. The answer to that question is 'it depends'. Like any form of metal cutting, sheet metal cutting, bending and folding is highly dependent on the gauge of the metal being cut, speed required and how one defines a quality job. It is also determined by what you want to use the sheet metal for.
Aluminum sheet metal is given special consideration when discussing sheet metal cutting since because of its relative softness; it delivers different results compared to other metals. There is a range of methods that can be used when cutting aluminum, from manual hand tools to industrial systems, some of them automated.
Chisel and Hammer
This method is straightforward and just involves striking the chisel along a line of your choice. To prevent the chisel's tip from wearing, use a board made of wood to act as a backer. This method however is tedious and slow in addition to resulting in a rough edge on the sheet metal that will need to be refined.
Aviation snips or tin snips, also described as rugged scissors, are effective when cutting aluminium sheets below 18 gauge. The snips come in three types made for left hand curved, right hand curved and straight cuts. Like the chisel, a cut by snips needs filing to clean up the edges.
Effective when dealing with smaller pieces of sheet metal, the hacksaw has a limited throat depth. However, using it will mean you consider a replacement since aluminium wears hacksaw blades faster than wood.
These are hand held shears but smaller in size. The heat generated is not enough to melt the metal which is a good quality. On the downside however, you will have to deal with the sheet vibration, quality of the finish and noise.
Grinders are an available but not necessarily advisable option. Unlike power shears, grinders tend to produce more heat. This means the metal absorbs the heat and melts, leading to a dangerous bind once it re-solidifies round the blade.
Also portable, jigsaws require particular handling and knowledge when being used on aluminium. With the wrong blade and saw, you might damage the tool and sheet metal to be cut.
This is the most affordable method of sheet metal cutting available. The faster one cuts, the cleaner and smoother the edge will be.
For cutting thick or intricate aluminium, the water jet can focus a high-pressured jet of water (added abrasives) at high speed to wear away the metal. The edge will be smooth, which is why it is the preferred method for metal cutting.