Once the THC vape cartridge has been filled with the THC vape juice, it gets installed on a 510 thread battery.  Some of these batteries are "automatic" which means there is no button, you inhale, and a sensor turns on the battery, which applies power to the coil.  Others have a button that has to be depressed.   Once the mix inside the tank is made at a proper ratio and/or filtered from a stronger ratio, there is an entrance size to the coil chamber to account for.  If the THC vape juice is too thick, it cant flow the hole fast enough, dry puff occurs.  A larger hole or a thinner mix is needed.  Once the viscosity of the THC vape juice is matched to the coil hole entry size it should work every time, never giving a "Dry puff".  Dy puffs are very undesirable as they create a harmful foul burning taste by burning the coil dry.  This permanently damages the wick in the coil and every inhalation afterwards will taste bad.  The thinner the viscosity, the better the mix will flow into the coil.  The THC vape juice mix should flow into the coil so every pull is tastes as enjoyable as the last and the flavor of the concentrate still reigns through.