What is the role of hopper in VFFS machine ?

In VFFS machine, “hopper” is the parts mounted to the top of the VFFS machine that receive the products falling from weigher or other machinery of before-process. In other words, it is a “connector” to connect VFFS machine and Weigher.

It looks a simple receiver at first glance, but depending on the hopper design it causes issues such as:

• Product jamming
• Adhesion problem
• Unstable feeding
• Decline of packaging output

In other words, hopper is one of the most important parts of the VFFS components.

Why hopper design is important?

In our blog articles, we have featured various kinds of products to be wrapped with actual study case such as coffee beans or frozen products. However, the hopper itself has not been focused.

However, in fact, Products listed below have a variety of shapes, sizes, specific gravity and adherability.

• Snacks (Chips, Rice crackers)
• Frozen Food (French fries, dumplings or Fried rice)
• Coffee
• Gummy candies, chocolates and candies

Therefore, Hopper needs to be designed according to the product characteristics.
Even the same model VFFS machine, if the product to be packaged is different, then the hopper shape and size should be changed according to the products.
It is no exaggeration to say that Hopper design is the start point to determine the machine specification.

From the viewpoint of anti-sticking measures in handling seasoned snacks, salt or sweeteners in the seasoning powder may promote adhesion to the hopper.

If the adhesion continues, the following issues may arise.

• It may cause unstable product supply.
• It may cause contamination between the seal as the dropping time varies.
• It may cause hopper jamming.

The countermeasure against hopper adhesion is to design for smooth sliding.

• Change the material from flat metal sheet to embossed metal sheet.
• Adding surface treatment.

The measures against the hopper jamming due to the product size is optimization such as ;

• Convergence accuracy inner surface area from the hopper opening to the discharge port to VFFS machine.
• Slope angle of the hopper
• Opening dimension

From these, the hopper shape design makes decisive influence on the stable operation of VFFS machine.

Determination of hopper size

The most important thing to determine the hopper size is to check the actual product to be packed. In some cases, “To eat the actual product” or pick up and check the product is effective.
As mentioned above, saltiness or sweetness of snack products are issued from seasoning powder. Therefore, adhesion is depending on the ingredients. Checking the product by senses using eyes, tasting or touching is surprisingly important process.

Although we can’t just eat those products such as frozen food, as they are, their size and adhesion need to be checked.

Confirming with the actual product,

• Fluidity that cannot be judged by academic data alone can be checked.
• Actual jamming likelihood.
• Tendency of adhesion.

The hopper shape and dimensions are determined by examining the product characteristics first, and then by considering the limited installation height and requested packing speed. As a result, the hopper shape and dimensions for may differ even for product similar to each other.

This flexibility of design is the most important point for the stable operation of packaging machine, meaning, for meeting the customer’s expectation.

Conclusion

Hopper in VFFS machine, is the parts that affects machine performance.
The hopper in VFFS machine is not just receiver of supplied product.

• Design based on the product characteristics
• Structure to prevent jamming
• Influence to the packaging speed

Hopper is the parts relates to all above. That is why, even the same product category the hopper design may differ in each case.

Tam Contact to: tam-overseas@tam-tokyo.co.jp