How do powder filling and sealing machines work?
Introduction to powder filling and sealing machines
Pouch filling and sealing machines accomplish two main things: Dispense product into preformed pouches and then seal the bags shut.
There are two main designs for this machine type: Rotary and inline. The differences between the two are in the machine layout.
An inline pouch machine packages products in a straight line, with the beginning and ending points of the process at opposite ends, requiring more floor space.
A rotary pouch packing machine is laid out in a circular fashion, meaning the start point of the packaging process is right next to the endpoint. This creates a better ergonomic setup for operators and requires minimal floor space. Because of their popularity for powder packaging, we’re taking a closer look at only the rotary design in this article.
Rotary pouch fill and seal machines can feature one, two, or four bag infeed ‘lanes’, with a simplex (single lane) model being the most in-demand for powder packaging. When packaging speed requirements are in excess of single-lane output, a company can upgrade to a machine with additional infeed lanes to meet throughput needs.
On a rotary pouch packing machine, separate static ‘stations’ are laid out in a circular fashion, each one performing a distinct step in the pouch packaging process. There are usually between 6 – 10 stations on a rotary pouch fill and seal machine, with 8 stations being the most popular configuration. The interior portion of the machine moves in a counter-clockwise fashion, stopping briefly at each station.
1. Pouch loading
A worker will load premade pouches manually at regular intervals into the bag infeed magazine, which must be carefully shingled to ensure proper loading into the pouch packing machine. These pouches will then be conveyed to the interior of the machine one-by-one by a bag feeding roller.
In 2018, Viking designed a proprietary bag infeed featuring a robotic arm that uses vacuum suction to grasp each pouch and transfer it to the bag grippers. This innovative technology effectively eliminates the manual labor involved in loading and shingling pouches. Contact us today to see an exclusive video of this technology in action.
2. Pouch gripping
A set of bag grippers, one on each side, grasps the loaded pouch and consistently holds it as it moves through each station on the powder packing machine. On the best automatic pouch fill and seal machines, these grippers are on stainless steel arms and can easily support fills of up to 10 kg, even with high use over long periods of time.
3. Optional printing or embossing
If date or lot codes are required on the finished pouch, printing or embossing equipment can be added at this station. Both inkjet and thermal printers are available, with inkjet being the preferred option. Embossing equipment creates raised characters in the seal area of the pouch.
4. Zipper or bag opening & detection
Powder pouches are usually fitted with zipper reclosures. To fill the bag with product, this zipper must be fully opened. To do this, vacuum suction pads grip the lower part of the pouch and opening jaws catch the top part. The bag is gently opened, and at the same time, a blower blasts the inside of the pouch with clean air to ensure it is completely open. If the pouch does not have a zipper, the suction pads still engage the bottom part of the bag but only the air blower is engaged at the top of the pouch.
5. Powder product filling
Most utilized for dispensing powder into bags is the auger filler. This filling apparatus uses a long screw-type mechanism to dispense discrete quantities of powder into each pouch. Different auger configurations are required depending upon if your powder product is free flow or non-free flow.
Dust is most often released at transfer points in a powder packaging system. For this reason, a dust hood is recommended (pictured at right), which is placed directly above the filling apparatus to help contain the spread of airborne particulates.
In powder packaging, there will always be some loose particulates that end up on machine surfaces. It is vitally important to clean your pouch packing machine at regular intervals to prevent build-up that could impede operation or affect product quality.
6. Dust collecting, settling, or other options
There are a few options available at this point in the powder packing process:
- Dust collecting. A dust collector can be utilized at this station to remove any extra airborne particulates from within the pouch seam area before sealing.
- Product settler. To encourage the powder product to settle toward the bottom of the pouch, a settler can shake the bag gently.
- Scoop feeder. Some powder products require a measuring scoop within the package. The pouch fill and seal machine can be fitted with a bowl feeder and chute that dispenses a single scoop into each bag at this station.
- Load shelf. For heavier fills of powder, a load shelf can be added after filling to support the extra weight of the bag and remove some of the stress from the bag gripping arms.
7. Pouch sealing & deflation
To ensure all remaining air is removed from the bag prior to sealing, two deflator plates gently squeeze the pouch.
To seal the bag shut, a pair of hot seal bars close over the top area of the pouch. The heat from these bars causes the sealant layers of the pouch to adhere to one another, creating a strong seam.
8. Seal cooling & discharge
To flatten and strengthen the seam, a cooling bar passes over the heat sealed area of the pouch. The finished powder pouch is then discharged from the machine and deposited into a receptacle or conveyed down the line for further processing.
Free automatic pouch filling and sealing machine guide
Interested in powder filling and sealing machines, but unsure of what to look for when shopping for this equipment type? Our experts answer 10 top questions and explain what to look for in our free pouch packing machine guide