Fabrication of sheet metal ductwork involves cutting and forming. With cutting, shears and high-definition plasma equipment are used, while in forming, brakes and presses apply force to shape the material. With this equipment, precise cuts and bends can be created to create specific shapes and position ductwork around obstacles.

One of the most common solutions is rectangular metal ducts, which are formed by combining two bent pieces of sheeting. First, the flat pieces of metal need to be cut to the desired size using a plasma cutter or cutting machine. The sharp edges are then folded inward by another machine. The sheet is then shaped into an L or tube. Rectangular ducting is usually made to standard sizes, but custom sizes can also be created.

Another common option, round metal ductwork, is made using a different process. To begin the process, sheet metal is placed into a coiling machine. To make the pipe airtight, the machine fuses the edges together. Next, the pipe is cut to the desired length.