With incredible versatility, a single blow molding machine can produce products for multiple industries, including technology, medical, food and beverage, and consumer goods. Besides the examples mentioned above, workers also rely on this process to manufacture large plastic buckets, tanks, and more.
There are two types of extrusion blow molding processes. One is a continuous or intermittent preform process. In this case, the extruder runs continuously even though the preforms come from different sources. The other process uses an accumulator. This means that during accumulator head blow molding, the extruder refills the accumulator, preparing for the next injection.
Here are the five steps required to produce extruded products using a continuous method.
1. Plastic raw material enters the hopper mounted on the blow molding machine. The operator can add additives and colorants at this time, according to customer requirements.
2. Next, as plastic beads or granules leave the hopper, they pass through the feed throat. That part of the extrusion blow molding process involves distributing the material into the barrel, which has a large rotating screw.
3. While this is happening, the barrel is heated to its melting temperature. The combination of heat and rotation produces a molten resin with a bubblegum-like consistency.
4. Once the now-molten plastic reaches the end of the screw, it flows through a screen and a break plate. This part of the extrusion blow molding process achieves two goals. First, the screen removes any inconsistencies or contaminants from the plastic. As for the break plate, this effectively changes the movement of the plastic from rotation to longitudinal direction. At this point, the material is ready for the mold.
5. The mold ensures that the plastic flows evenly and smoothly as it leaves the cylindrical profile of the blow molding machine. Ultimately, the mold plays a crucial role in achieving proper consistency, thus maintaining the integrity of the finished product.
