The Blow-Fill-Seal liquid packaging process is a series of sequential events, all occurring inside a single machine or a single production line.
• First, a single machine forms the polymer container.
• Then the same machine fills the container with the sterile liquid.
• And it ends by hermetically sealing the container’s opening.
Then the process repeats itself. And this all happens within a matter of seconds.
Details of the BFS process vary by machine model and manufacturer. But all BFS models perform the same general functions. Here’s a look at how the BFS process works on a rotary BFS machine – specifically a bottelpack 460 made by Rommelag.
First, inside the technical area of the BFS machine, pharmaceutical-grade plastic resin beads are heated and extruded to form what is referred to as the parison. This parison is held open by the introduction of sterile filtered air.
As the parison descends, the mold comes together around the soft polymer and forms the shape of the container. The molds are cooled by internally circulating cold water that rapidly cools the polymer and locks in the shape of the container.
In the middle of the parison is a filling mandril that holds a filling needle for each of the containers being filled. Depending on the shape of the container and the volume of liquid, there may be up to 25 containers being formed and filled at each cycle.
These filling needles are jacketed with a cooling liquid that protects the liquid drug or vaccine product from the heat of the parison. The drug, often contained in a tank, is under positive pressure to maintain sterility. A solenoid is used to deliver a precisely metered dose of the drug product to the container.
In this specific rotary BFS machine, the 15 or 20 sets of molds move in sync with the parison. As one set of molds moves down away from the filling needle, the bottom of the next set of molds seals the container, while the top of the mold forms the next container.
Lastly, the BFS molds open, allowing the filled and finished BFS container to leave the machine in a continuous strip and move on to the next phase of the manufacturing line. The BFS process is then repeated for the next series of containers.