How Products are Loaded and Sealed into Pre-Made Bags and Pouches

Welcome to Package This — your guide to packaging machinery and materials, produced by the Emerging Brands Alliance in conjunction with Packaging World and PMMI, the Association for Packaging and Processing Technologies. 

Today, we're exploring the world of pre-made bag loading and sealing equipment – machines used extensively by consumer packaged goods companies, or CPGs, for countless products. This technology is used to fill candy and snacks into pre-made standup plastic pouches, put meat and cheese into flat plastic bags, and fill grains and pet food into large paper sacks.

This type of equipment is also used to bag and pouch and seal common non-food items like hardware store parts and electronics into pre-made bags.

With these machines, note that “pre-made” is the operative word when describing the type of bags they run, to differentiate them from form/fill/seal bagging systems, a distinct technology we will explore in a future episode.

Bag and pouch sealing equipment is perhaps one of the most common types of machines in this group. These machines are the choice for CPGs with a separate bag filling machine upstream in their packaging operation. Dedicated solely to the function of sealing pre-made bags or pouches, they are used in various industries.

Unsealed bags with products inside are conveyed from the filler down to the sealer to create a secure seal that keeps the contents of the bag or pouch intact until the consumer breaks the seal. Common sealing technologies include continuous heat, ultrasonic heat and impulse heat sealing, as well as stitching, a non-heat method. Choosing a sealing technology will depend on factors including the bagging material and size of the bag, not to mention the product.

The Doboy CBS-D 750 from Syntegon, shown here running flat bags of tortillas, is a good example of a bag and pouch sealer that uses a continuous heat method called band sealing.

The machine’s tapered infeed extension makes it easy for operators to feed bags straight into the sealer. Its compression unit removes air from the package prior to sealing to help preserve freshness. As the bag passes through the machine, a heated band seals the plastic material, creating an airtight seal. Syntegon also supplies this unit with a DRD bag top trimmer that removes excess plastic before sealing for a clean appearance.

One advantage of this type of equipment is its flexibility. For example, CPGs might use the same machine to run several different types of plastic pouches or even paper formats on the same machine, with quick changeovers between the different runs. These bag loaders, fillers, and sealers are also an option when doing shorter runs, or where high production speed is not the main consideration.

Bag loaders, fillers and sealers are used in a wide range of applications from packaging snacks, grains, candies, and pet food, to even non-food items such as hardware pieces like nuts and bolts.

PAC Machinery’s Rollbag® R3200 Auto Bagger is an example of this type of equipment, shown here packaging clothing for retail fulfillment. This machine can work with various types of bag materials, including polyethylene, paper, metallized polyester, and Tyvek/poly blends. The Rollbag R3200 Auto Bagger can also be equipped to load, label or print, and seal bags in one step, making bagging operations more efficient for brands. Here, we see an operator feeding product by hand, but PAC Machinery can also add automatic infeed devices to this machine.

For non-food packages, air in the headspace of packaging is usually not a top concern, but when it comes to food packaging, it almost always is. Systems that modify or remove air from inside a package can significantly increase the shelf life of the product it carries. 

Now, let’s look at Modified Atmosphere Packaging, or MAP, used in the food industry to extend the shelf-life of perishable food products by modifying the air inside the packaging. MAP machines flush out oxygen and replace it with a mixture of other gases, such as nitrogen and carbon dioxide. This technique slows down the growth of microorganisms and delays oxidation of the food. Brands can adjust their MAP systems depending on the food type, its respiration rate, and the targeted amount of time for the shelf-life extension. MAP technology not only helps maintain the freshness and quality of food products, but also can reduce food waste and improve food safety.

In this video from Paxiom’s Weighpack Systems division, we see a MAP bagging system in action. To the right of the screen, you see a rectangle. This is where the injection of gases to modify the package’s atmosphere takes place. It uses a gas flush snorkel to inject nitrogen or other gases into the package, and then closes the package around the snorkel to create a modified atmosphere. This process is designed to achieve the best possible MAP results and does not result in any loss of production rates.

Another type of bagging technology based on air within the package – or more appropriately in this case, the lack of it – is Vacuum Packaging, used to tightly wrap preformed bags around perishable food products.

An operator places the bag into a vacuum chamber, where air is flushed out, eliminating oxygen and air pockets for optimal preservation of the freshness of the food. Vacuum packaging equipment is widely used on meat, cheese, and poultry packaging lines to extend shelf life, maintain flavor, and prevent spoilage throughout the supply chain. It can also be used in packaging medical devices and supplies, electronics, or any other sensitive product that requires airtight packaging.

This machine, also from Weighpack Systems, demonstrates what a vacuum packaging bagging system can do. Similar to the previous example, this system also closes the package around the gas flush snorkel during the vacuum process. This unit is highly flexible in that it can handle vacuum and MAP on the same machine. Both vacuum and MAP machines from WeighPack Systems feature customizable settings based on user requirements for time and pressure.

Our next two categories are frequently used in closing and sealing large, open mouth bags.

First, bag sewers are designed to seal preformed bags by sewing threads, as opposed to most heat sealing methods. Such equipment is commonly used in sewing the open mouths of typically large, heavy-duty bags, such as pet food bags and sacks of potatoes. They can be used to sew a variety of bag materials, ranging from paper to poly woven materials and even burlap bags.

As a filled, open mouth bag is conveyed through the system, it passes through a closing mechanism that shuts the open mouth shut and then sews cotton or plastic thread to seal it up.

Lastly, there are also other types of bag closers used in open mouth bag systems for large, heavy bags that don’t involve heat sealing or sewing. Included here are bag closers such as crimping sealers, plastic inner liner sealers, and pinch bottom open mouth glue sealers.

Pinch bottom sealers use a pre-glued seal that is activated just before sealing. Moving through the machine, the open mouth of the bag is pinched together, forming a tight seal that can secure heavy-duty bags of products like bulk grains, fertilizer, powder ingredients and related products.

From machines that modify the air inside a package or remove it… to units that fill, seal, or close stand-up pouches…to sewers and closing of large, heavy bags, these pre-made bagging loading and sealing machines run the gamut.

We hope you have enjoyed this video and learned a little about this fascinating area of packaging technology.

For more videos on packaging machinery and materials, please subscribe to our full Package This series on YouTube. And for a deeper dive into the technology we discussed here, explore PMMI ProSource, a searchable directory with 1,000 packaging and processing suppliers. Visit ProSource.org to search suppliers by package type, material, or features. Thanks for watching!