How a tattoo machine is running is referred to as machine function or machine set-up. There are two factors that describe machine function. They are:

• the speed of the machine
• the force of the machine

The REQUIRED SPEED of a machine is determined by the tattooing process being done. An outlining machine runs faster than a machine used for coloring. A machine used for shading runs at a speed somewhere between the two. The exact speed at which a machine should run is dependent upon each tattoo artist's style and personal preferences.

The REQUIRED FORCE of a machine is determined by the needle configuration being used. Closely spaced needle configurations require more force. Needle configurations with more or larger diameter needles require more force. Needle configurations made of short taper needles require more force than similar configurations made of long taper needles.

Machine function is the working outcome of the combination of the parts and adjustments that are present on a specific machine set-up. Any alteration to machine function becomes complex due to the interactions of the machine systems.