The extruder is a important part of the 3D Printer and consists of a filament driver part (Cold End), where filament is pushed by a motor and a part that heats up the filament (the Hot End). The difference between the Bowden and Direct Drive solution is that in a Bowden system, the filament is transported through a tube, generally in a bow, between Cold End and Hot End. In a direct drive system there is almost no distance between the two. The term Direct Drive is ambiguous, as it may also mean that there is no gear transmission between motor shaft and filament.
Some advantages of Bowden over Direct Drive include:
Of course there are also disadvantages: