Once in the Factory defeat the grunts You encounter. Follow the conveyor belt until You get to the section with stairs. Go up.
Poké Ball Factory
If you try to visit before obtaining your sixth badge, you won't be able to enter. After defeating the Laverre City Gym, your friends will meet up with you outside of the gym and tell you they plan to visit the factory. They'll clear the way, allowing you to enter. Before going inside the Poke Ball Factory, explore the hedge mazes in the front. Above the Max Revive is a hidden Hyper Potion at a dead end. Take the bottom path of the maze to find a hidden Poke Ball at the dead end.
The factory is mostly automated and only a few people reside there to observe the process. The factory area consists of the factory itself and the yards, where two small hedge mazes reside. Inside the factory, two conveyor belts run through the building, allowing the player to move around. The direction of the conveyor belts can be temporarily reversed from a computer at the southwest corner of the facility.
Shauna and Trevor are standing outside, saying that someone won't let them into the factory. Shauna runs north to try to get in again. Then your neighbor and Tierno arrive. Tierno runs off to help them, and your neighbor says to check out the factory while the guard is gone. Go north through the gates, then go east into a shrub maze. Turn on your Dowsing Machine to find a hidden Hyper Potion in the maze. To the south, there is a Max Revive. Now go west and into the shrub maze there. To the north, there is a hidden Burn Heal, and south of that, you find a Max Ether.