I know of at least one product that uses both injection molding and blow molding. My wife toured the Zephyrhills Water plant and saw the process of bottling water.
The 16 oz bottles have a screw top for the cap that has to be fairly precise. The bottle blanks are injection molded into what look like little test tubes with a threaded top. The blanks are very rigid, not what the final bottle feels like.
The blanks are then fed into a blow molding machine where the blank is heated. Air pressure is applied to the blank to blow, or push the walls out so they meet walls of the mold. This gives the bottle its final shape. The finished bottle walls are a lot thinner now and the bottle is taller and wider than the blank.
