The VFFS Sealing Process and Identifying Constant Heat Seal Parts

When looking at the OEE (Overall Equipment Effectiveness) of your VFFS machine, it is important to know various parts and processes, especially for technicians in charge of supervising or providing maintenance on the machine.  Your operators and maintenance teams are your first line of defense against unplanned downtime, spare part failure, and incremental drops in OEE over time. Equipping them with training and experience allows for efficient running of the vertical bagger and effective troubleshooting.

The constant heat sealing system of your VFFS machine is the focus of this Tech Note.  In particular, we will look at and identify the constant heat seal jaw components and the various stages of the sealing process.  

In order for the constant heat sealing system to produce high-quality seals, it must be properly set up.  This setup of the jaws consists of jaw carriers, constant heat jaw inserts, spring-loaded bag grippers with cooling, a cutting knife, bevel plates, and air deflators.  It is important to note that jaw alignment and spring bag gripper alignment are critical to quality seals. The photos and descriptors below provide visual identification of the constant heat sealing system parts as well as a run-through of the vffs sealing process.

Constant Heat Sealing Jaw Cycle

PRE-SEAL:  After travelling over the forming collar and through the filling tube, the film advances through the jaws as seen in the picture below after being filled with product.

 FIRST STAGE:

• The horizontal seal jaws start to close
• The bag grippers hold the lower package in place
• The deflators push the air out of the lower bag
• The Product drops onto the bevel plates  NOTE:  This will change depending on the product

SECOND STAGE:  The cutting knife extends out to cut the film before the upper and lower seals are made. 

THIRD STAGE:  The heated jaws touch to seal the bags for the upper and lower seal.

FOURTH STAGE:  The jaws open and a cooling time and distance is set in the HMI to begin cooling the seals while the grippers are still holding.  NOTE:  This is important for making strong seals. Cooling is essential yet can be an area often overlooked by operators.

FINAL STAGE:  Jaws open to advance the next bag

The constant heat sealing system is important in maintaining a tight seal and keeping the integrity of the bag intact. Sealing pressure, temperature, timing and cooling are the key factors involved in this system and can be highly programable, depending on your VFFS machine model. With knowledge of the process and components involved, you will have an edge in making sure these key factors are met, maintained, and repaired if issues arise on your VFFS.  

If these steps don't solve your issue, please contact us to schedule a service visit with our Service Manager, by calling 404-640-5322, or you can chat with an expert live in the chat box on the right 👉👉