If you really desire that your system should move from STL to part in 24 hours then it is quite obvious that you have to find out the best suitable rapid prototype methodology to achieve the objective. One of the methods of rapid prototyping that can achieve this objective for you is the 3D printing. 

You can start your process by depositing one layer of powder objects at the top slot of the fabrication chamber.  The task can be accomplished by dispensing specific quantum of powder from an identical supply chamber.  A piston is moved upward incrementally to achieve this goal.  The roller helps in even distribution and compression of powder on top of the chamber.

Multi-channeled jetting head that is used for the purpose will also deposit liquid adhesives if you are using the 2D patterns.  This liquid is deposited on the bonded layer of powder.  In this process the liquid adhesives and deposited in 2D pattern on the layer of the powder.  The powder is bonded in the areas where the adhesive has already been deposited and thus forms one of the object layers.

After the layer is formed the fabrication piston will be moving downward by the thickness of the layer.  The process is repeated time and again till the object is formed within the bed of the powder.  Once the entire process is completed, the object is elevated.  The extra amount of powder deposited is brushed away that leaves the final green object.  Your Rapid Prototyping process is now complete.  Since the powder bed supports the overhangs you do not require any extra support.