The working principle of vertical form fill seal machines consists of the following steps.
- Packaging material unwinding
- Pouch forming
- Vertical sealing
- Bottom sealing
- Product filling
- Top ceiling
- Cutting and discharge
Packaging material unwinding
Usually, the packaging material is available in the form of rolls. Therefore the material is put in the form of rolls and is used through unwinding. There are several rollers through which the film is pulled out and tensioned. There is also a weighted pivot arm so that it is ready for good forming. At the back of the machine, the unwinder is also adjusted.
The material is put into the machine on a platform and then tensioned to the filling tube. Keep in mind that pouch shape is provided to the packaging material so that they will be able to perform the filling. This process is done at the specific part of the forming tube, also called the forming shoulder.
Around the forming tube, the packaging material is twisted and then pulled along the tube. This thing then starts the following stages of the filling process. For the movement of the film, some pull-down belts are installed just after forming. You can also find some designs in which the sealing jaws are used to pull the film.
When the packaging material is shrouded around the forming tube, the first sealing is done on the side. So there is an overlap while wrapping the material around the tube. For vertical sealing, it is essential to make the packaging bags according to the perfect width of the packaging reel and the forming collar.
You can find many sealing bars or sealing jaws pressed together to make a perfect layer. Therefore the overlapping material is pressed and weld through heating. With the help of heating the material, a side seal is formed. Along with all this discussion, keep in mind that there are different shapes of the seals.
After the above process, it still can not be fed to the feeding tube. You cannot add it to the feeding tube because, at this time, there is no bottom seal present.
This thing is done why some sealing bars. At this moment, the ceiling bars are also welding the material through heating and pressure. Also, the desired pouch is made at perfect length according to the length of the material.
As the name shows, in product filling, the product is put into the system. The dosing system is then placed near the forming tube. The dosing system’s primary function is to run the system the amount of product to dose. After that, the material is then poured down to the forming tube and then put in the pouch for making the packets.
It is the second last stage of the process in which top-sealing has been done. When the product’s dosing is completed, the same sealing Jaws which performed the bottom seal have activated again.
Therefore in this way top seal is created, and in the end, closing the pouch. There are some designs in which the sealing Jaws are equipped with vertical movement up and down. This design allows us to pull the film along the machine. Then the film is unrolled from the reel present on the unwinder.
Cutting and discharge
After closing the pouch, the cutting and falling to a collection system are done. A belt conveyor is always there to take the pouch to the next packaging step.
The following packaging step is to put it into the box.
Intermittent or continuous filling
The intermittent or continuous filling is a little bit different from the simple process. The only difference is that all the steps are repeated just like the above but with more speed. Therefore faster designs will allow the continuous process that is available with some suppliers.
The filling speed is usually 30 to 80 pouch per minute in that process if we consider an intermittent VFFS packaging machine. On the other side, the machine can fill almost 100 to 200 or even up to 300 pouches per minute for a continuous vertical form fill seal machine.