Vertical Form Fill Seal Machines

1. Film Transport & Unwind

Vertical form fill and seal machine have a rolling stock at the backside of the machine, a sheet of film material wrapped around a rod. The film material used can be polyethene, foil laminates, paper laminates and cellophane laminates. The whole sheet of wrapped film material is called film web.

The most commonly employed film transport method in VFFS is film transport belts installed at the sides of the forming tube, which itself present at the front of the machine. These transport belts pick up the film sheet and bring it into operation. Sealing jaws transport the film sheet through the machine itself, without the help of belts, in some models.

A power unwind wheel can be added as customization that facilitates the transport belts in the sheets unwinding process. This customization is quite beneficial with heavy film rolls.

2. Film Tension

A pivot arm also referred to as dancer arms, is present at the back of the machine and is equipped with a series of rollers. The unwound sheet of film is forced to pass through the arm, where it is kept under tension with the up and down movement of the arm. This is done to keep the sheet intact and in place while it’s moving.

3. Optional Printing

A thermal or Ink-jet printer can be installed in the printing unit. After passing through the arm, the sheet comes in the printing section, where a printer prints logos, dates, codes and other specifications on film.

4. Film Tracking and Positioning

After printing is done, the film sheet is transported to registration photo-eye. Registration photo-eye manages the film transport belt by detecting the printed registration mark over the film. It keeps the film in the right place to ensure that it is cut from the accurate point.

The next station in the way of the film sheet is the film tracking station, which holds many sensors to supervise the position of the film. A slight change in the normal position of the film can send a signal to move the actuator that may result in shifting of whole film carriage to one side or the other according to the need to restore the original position of the film.

5. Bag Forming

The forming tube is the next part that comes in the film’s way. This is the phase where bags are manufactured. After coming in contact with the collar of the tube, the film folds around the tube in a way that the opposite ends of the film overlap each other.

The forming tube is capable of making two kinds of seals: lap seal and fin seal. In the lap seal, the outer side of overlapping edges of the film is sealed, resulting in a flat seal, whereas, in the fin seal, the inner side of two outer edges is joined together.

If we compare these two, the lap seal is more attractive and requires less material to form. Besides the collar of the forming tube, a rotary encoder is present that drives the moving film. For every length of movement, a signal is developed that is passed to the programmable logic controller. The bag length is adjusted on the PLC display, and once this length is reached, the encoder stops the film’s movement. ( The film’s motion is only stopped in Intermittent motion machines, not in Continuous motion machines).

Two gear motors which regulate the motion of friction pull-down belts are responsible for bringing the film down. Friction pull-down belts are often used for dusty products. Vacuum suction pull-down belts can be substituted for friction belts on demand.

6. Bag Filling and Sealing

On Intermittent motion machines, the film will stop for a while so the bag can get its vertical seal. The pre-heated vertical seal bar travels forward to bond the vertical overlaps of film together. On a continuous motion VFFS machine, the film doesn’t stop, and the vertical seal bar remains continuously in contact with the film to provide a seal.

After this, the top seal of one pouch and bottom seal of the next pouch is made with the help of horizontal sealing jaws. In Intermittent motion packaging machines, there is a pause in the film’s movement, which is followed by a horizontal seal from jaws that move in an open-close pattern. In continuous motion VFFS equipment, the film does not stop, but the horizontal jaws move up and down with an open-close motion to seal the moving film. Some models of continuous motion machines have two sets of sealing jaws for extra speed.

For heat-sensitive materials, industries have a cold sealing system that uses ultrasonic waves. The ultrasonic waves generate vibrations that produce friction at the molecular level; this friction raises the temperature between film layers, resulting in the bonding of layers.

The sealing process is followed by filling of product in the bags. The precise amount of product is filled in the bags with the help of a filling device such as auger filler or multi-head scale. The filler is not a part of the Vertical form fill and seal machine; it must be purchased additionally. Most companies integrate a filling body with a packaging machine.

7. Bag Discharge

The sharp knives present in the sealing jaws then cut the product filled bags. This is the point where one packaging cycle completes in Vertical Form Fill and Seal machine. Depending on the machine efficiency and bag size, a VFFS machine can fill 30 to 300 bags per minute.

This finished product is then transferred to downline equipment via a conveyer belt or receptacle for further processing, i.e. Quality tests, carton packing, case packing.

• Versatility

VFFS equipment has a broad range of uses. A Vertical Form Fill and Seal machine can be used to produce bags of different shapes because some parts of this machine, like forming tube and forming collar, are so easy to replace.

For example, let’s take chips; they are packed in bright, pillow-shaped bags, while breakable biscuits are packaged in colourless, high-quality bags with a block bottom. Both of these bags can be conveniently created in the same VFFS machine.

• Ability to Use a Wide Variety of Materials

A VFFS machine can process multiple packaging materials. It is an excellent feature because different products have different packaging demands. Each layer of packaging film has its specific function. The packaging material should not be poked so that the crisp of snacks and salty food and the fragrance of coffee can be preserved for a longer duration. Furthermore, lamination should be applied to the packaging layers for extra strength.

• Low operational cost

VFFS machines can greatly benefit your business because they offer very low packaging cost. Moreover, these machines can last for many years if they are maintained properly and regularly.

• Air Tight Package

Airtight sealing is one of the main packaging requirement out of many. Modified Atmosphere Package is the latest innovation to add more protection to products; in this packaging technique, the air inside the package is replaced by an inert gas to neutralize oxidation and improve the product’s shelf life.

• Labelling and Printing

Vertical Form Fill and Seal machine are compatible with printers and labellers. They can be integrated either separately or combined. The printer is used to print various specifications and information about the packed product. In contrast, a labeller is employed to put the label on products.

• Extras

Not just printers and labellers, you can add many other devices to Vertical Form Fill and Seal machine to improve and facilitate the packaging process. For example, open aids can be added to the package, which assists in opening and re-closing the package.

A Vertical Form Fill and Seal device from a well-trusted brand will deliver optimal, authentic and quality final products. These machines may cost you a big amount of money, but they require little maintenance and save your packaging cost in the long run.

• Quick results

The whole operation is automatic; the machine itself carries every step of the operation. That’s why the packaging process finishes quickly.

• Comparatively Inexpensive

VFFS machines can seal products without costly packaging materials.

• Flexible Solution

The machine is capable of packaging solids, dry and liquid products.

Tip 1: Align machine design to the highest volume package

Most customers prefer to purchase a vertical form of seal-fill machine. It is characterised by large enough space to package the bags from the widest down to the narrowest. This machine provides the details allowing it to automate the entire operation. The only discouraging features are the bigger form or sealed bag and its relative expensiveness. This type of large volume machine tends to perform filling and sealing for only big wider bags, but it is not favourable for smaller ones. So, it is used mostly in industries where wider bags are desired to process.

The selection of machine is most effective in these processes. The most common way of machine selection is that the machine width should be according to the highest volume bags under processing and the size of bags that needs automation of the whole operation. The machine using bread and butter will be optimized when it runs faster and yields the least cost with maximum effectiveness using the least materials. For the processing of semi-automatic operations and other sized bags, it is required to run another machine to fulfil their relative conditions. If this one machine is under processing for different bag sizes and conditions all the time, then it will be master of none. It suggests that this large vertical form fill and seal machine can not be used for small sizes bags. It means that every machine has specific features and should be used for particular operations.

Tip 2: Work with an OEM that understands the application

This will be challenged to manufacture a machine that tends to run effectively for years without any issues. The relative manufacturer should have a magnificent record of success and be aware of identical applications in terms of product and film type. The manufacturer knows well what is required to be successful in this application.

Tip 3: Be open to packaging suggestions

 Some customers visit the OEM and say, we want to run this identical bag. Matrix suggests customers stay open to alternatives. A slightly different width, length, and film type can be manufactured with much better quality and efficiency than the original on a high-speed automatic machine. This doesn’t mean that the original size can not be produced. There should be options open to packaging suggestions. Moreover, expect the manufacturer to provide the sample bag of every size and quality. Suggestions can be implemented to work with manufacturers to improve size options and quality.

Tip 4: The manufacturer should be able to recommend a number of film suppliers

 The film companies invest in the latest manufacturing technology to reduce cost and improve effective performance. The machine OEM should have the best working experience of the best film manufacturing and recommend the best ones suited to the relative application. Do not purchase the film from the form-film-seal OEM because it is simply a revenue maker and not in the right interest of the buyers.

Tip 5: The machine OEM should provide flexibility in fillers

The filler apparatus is a specially designed machine that gathers the project and is synchronized to meter product into the form-fill-seal machine. Fillers are optimized for the kind of product being packaged. Fillers companies are expert in different designs for various products. There can be multiple fillers attached to the machine during the life of one form-fill-seal machine because of changing product mixer nature.

The form-fill-seal manufacturer of choice will have the software already installed on their machine to synchronize several fillers. As time passes by and fillers are changed, the vertical form-fill-seal device synchronizes to the new filler, which leads to optimum installation time and higher uptime for the machine. In its standard software package, the matrix has eight different control techniques for synchronizing fillers. With this software strategy changing fillers is so easy. Working with external film suppliers and having the flexibility of switching fillers ensures that the device purchased today will grow with the company’s future needs.

Tip 6: Toolless changeover and other key operation strategies

Being able to run a number of bag sizes effectively – similar widths and various lengths – on one machine gives the industry more elasticity. A fast method to “change over” the machines between different pouch sizes is to have the machine operator switch among different size filling tubes without the need for wrenches, screwdrivers, and other tools. This is called toolless changeover, and it is a must for the organization because it is fast, effective, and does not require personnel maintenance to be taken.

A new bag size means a new film role requires to be rolled onto the machine. The form-fill-seal OEM should illustrate stringing a new role. If this process is time-consuming and cumbersome for the OEM, it will be difficult for the manufacturer to meet the required production because so much time will be lost during the changeover process. Speed and simplicity are desired in this changeover process. Another important characteristic that requires attention is the operator interface. The interface should be intuitive and multilingual to accommodate a range of operators. The onscreen help should be functional. It doesn’t need a software engineer to be operated.

Tip 7: Beware of 360-degree timing

360-degree timing has been the norm in form-fill-seal machines for past generations.  As the packaging film is pulled down, formed, filled, and sealed, timing cams complete one whole revolution – 360 degrees. The temperature, time, and pressure of the sealing process are all set to that one revolution. For instance, a 360-degree machine may be calibrated at the factory to run 30 bags per minute – 30 360-degree revolutions per minute. This speed feature is made set for the relative product during the installation of the relative machine, as in the previous example, it runs optimally at the 30 bags per minute speed. However, what happens if the buyer wants to speed up or slow down the production rate for any number of reasons? Then all of the timing cams on the machine must be readjusted, a time consuming and frustrating task to accomplish and to get done rightly.

 The latest generation devices do not employ 360-degree timing. The optimum sealing temperature and time are not affected by speeding up or slowing down these machines. Ask the OEM if they are using 360-degree timing. If they are using it, look for more advanced control and timing technique. 

Tip 8: The base price should comprise stainless steel construction, registration capability, and automatic web guide control

   Some OEMs keep the price of machines down by leaving out essential features. Without those features, the machine is no pennyworth. Ascertain whether the machine’s base price covers stainless steel manufacturing, registration capability, and automatic web guide control.

• Stainless steel is crucial for long service life and food safety.
• Print registration ensures bags and copies line up.
• Automatic web guide control guarantees reliable sealing, optimum productivity, and less waste.

 If the base price of the machine does not include these features, ask the OEM for the machine’s price with those qualities. Because with all of the other features mentioned in this white paper, they are necessary for an absolute equipment feel.

Tip 9: Ask the producer for the average annual operating cost

 The parts on the machine, such as the knives, cartridge heaters, and ware strips, are considered consumable because they must be replaced after a certain time. Like knife cylinders that work at warm temperatures, parts other than describes above need to be changed more frequently than other components, but not as often as spendable. On-going disposables and replacement part costs should be such that it is in a purchasing decision range. The OEM should have this data of the operation.

Tip 10: Keep it simple

Elaborateness and dependability tend to be at odds. Ask the OEM for its plan arrangements. Do the words come up? Open the controlled press to check the differences in appearance and number of components between suppliers. Is one clean and organized, and the other crowd?

It is also a good way to visit and consider the manufacturing plant process. Ask the design engineers about their basic layout design and features. Observe how common useful chores on the machine-like changeover are carried out. It will not be much easier for the operator if it looks hard for the employers. Talk with the OEM’s clients. Ask those customers about their purchasing chops.