Introduction to Industrial Bag and Sack Handling

Industrial material handling can take many forms. Whether you are handling packaged goods or raw materials, each scenario presents unique challenges. Things are no different for organizations that handle materials enclosed in bags. Whether an organization is filling and distributing product in industrial bags or receiving raw goods for use in production, both scenarios require attention to optimize your end results.

• If you work in raw goods, you are usually filling bags. This is especially the case with bulk powders or granules (for example: flavorings, chemicals, or active baking ingredients).
• If you are in food and beverage, pharmaceutical, chemical, or another industry that commonly handles bulk dry goods, you are likely lifting bags and using the raw material in production. A common example is pouring bags into a hopper for mixing or some other blending process.
• Then there are other areas where the bag is simply an intermediary container that replaces a box due to the form of the materials, such as coins. TAWI has customers that are tasked with wrapping coins into rolls for banks or other organizations. Prior to that rolling process, how do you think they are handled? You guessed it! Bags.

Today’s modern manufacturer tends to look at material handling of bags or sacks through a few critical lenses:

• What is the fastest way to handle our bags? Do I hire more people, install automation, or find something that is between the two?
• What is the easiest way to handle our bags? Is it simpler to just heft the bags manually or is there a better mechanical solution I can utilize ?
• What is the safest way to handle our bags? If I have a person involved – what do I need to consider to prevent an injury and its significant workers comp expense?

Depending on a person’s individual role in an organization, each of these deciding factors has e a different weight when designing your production. However, most people can agree that all three of these factors play a role in standard operating procedures. Speed is critical for efficiency, throughput, and cost. Ease is critical for employee adoption, satisfaction, retention, and enablement. And finally everyone agrees that safety is the top priority – everyone should go home at the end of the day just as healthy as when they came to work in the morning.

Before an organization can land on a solution, they need to take stock of how they currently operate. Then, it’s crucial to decide what will integrate into their production quickly, deliver a rapid ROI, and maintain maximum uptime without incurring too much additional cost. So where to  start? Let’s first look at the bags themselves.

Types of Industrial Bags and Sacks

Industrial bags offer a flexible packaging option for many. Bags can be cost effective, store easily, and be airtight to keep materials fresh. There are a variety of industrial bags and sacks that you may need to handle:

• Industrial paper bags including: multi-wall paper bags, poly lined paper bags, pasted open mouth industrial paper bags, pasted valve industrial paper bags, pinch bottom industrial paper bags, self-standing open mouth industrial paper bags (block bottom), and paper based paper bags that come as a part of a reel and are manufactured directly on a packaging machine.
• Industrial synthetic or plastic bags including: foil industrial bags, woven polypropylene bags, woven polypropylene laminate bags, polyethylene bags, gusseted synthetic bags, pillow bags, bulk bags, pasted open mouth industrial synthetic or plastic bags, pasted valve industrial synthetic or plastic bags, pinch bottom industrial synthetic or plastic bags, self-standing open mouth industrial synthetic or plastic bags (block bottom), and paper based synthetic or plastic bags that come as a part of a reel and are manufactured directly on a packaging machine.
• Woven burlap or Jute bags: Woven burlap and jute bags are very common in dry goods such as coffee beans and tea leaves.
• “Soft Containers” (Generally called ‘totes’ or similar): We will not address these in as much depth in this article as they can vary widely from application to application, but at TAWI, we treat zippered soft containers or anything enclosed in fabric, synthetic materials, or paper that do not have a rigid structure as a bag . This can include fabric totes, plastic wrap, heat sealed plastic wrapped containers, industrial garbage bags and more.

Different materials can have an impact on how you can handle a bag, especially when automation is applied. If suction is applied to the bag, it’s important to know how much air leakage can be expected on average. Also, if the bag will be grabbed mechanically, it’s good to know how durable the bag is and if it can support the weight of the contents of the bag given the method used to suspend it.

Challenges of Bag and Sack Handling

You may be familiar to the phrase ”like a sack of potatoes”. People use that phrase to describe something that is unruly to handle. In reality, they are talking about all of the downsides of bag handling. Something that you and your employees may experience every day as a part of the job.

Five common bag challenges  include:
• Bags change shape based on how they are handled, stacked or filled, which adds challenges for stacking or palletizing.
• The center of gravity in a bag can shift,  which means employees can be more prone to back injury than in other scenarios.
• There are no hard edges or corners typically to hold onto like a solid or firm box, which means the item is more cumbersome to hold.
• Media density plays an important role in how the bag is handled and behaves, especially in all of the previously aforementioned areas.
• And finally some materials used for bags are very porous and may present challenges when it comes to automation and air leakage, such as  jute or burlap.

So how do we mitigate all of these issues to ensure faster production, safer employees, and a more flexible workforce?

The TAWI Solution for Bag Handling

TAWI manufactures a variety of ergonomic lifting devices: everything from container unloading devices to portable electric lifts. Our flagship line of products is our line of vacuum lifters – also commonly referred to as vacuum tube lifters, tube lifters, or simply a vacuum lifting crane. These devices are simple lift assists capable of handling materials up to 600 lbs. Vacuum lifts can be used for a variety of materials and form factors and are comprised of the following:

• An overhead crane (either bridge or jib style) that can be fixed to a building, free standing, or on a portable structure
• A suction head attached to a lift tube for the operator to control the vertical motion of an item being lifted – Note: the operator does not exert any force for lifting and solely controls the lifting head through buttons, knobs, or handles
• A lift tube to expand and contract vertically while carrying the lifting load
• A vacuum pump to generate suction and associated hoses to supply suction to the suction head
• Lateral trolley tracks to allow for free movement of the suction head and lift tube to reach a product or to help move a product once it is picked up

For operators of vacuum lifts, it suddenly matters a lot less if they lift one 50 lb. bag or one thousand 50 lb. bag in terms of physical fatigue. Why? Because they are not doing the lifting portion of the process. They are no longer a source of lifting and are simply controlling the lifting device that is doing the work. That means the operator can work faster, for longer periods of time, and is less prone to injury or error. Employees no longer need to be strong enough to lift a 50 lb. bag. Instead, they just need to be strong enough to squeeze the control handle on their lifting device.

At TAWI, our strength is in smart handling. We design unique solutions that take our customers’ applications into account to not just do the job, but do it better than other available solutions on the market.  In fact, we invented the vacuum lifter and mobile order picking technologies and have 40 years of expertise.

How a Vacuum Lifter Solves Bag Handling Challenges

As mentioned earlier, there are several factors that make handling bags unique when compared to more structured or rigid containers. Let’s dig into each of these factors a bit deeper.

Bags Change Shape During Handling

Because the contents of a bag can shift around with movement, bags commonly change shape when  being handled. Why does that matter?

Firstly, it affects how the employee stacks or palletizes the material. If the employee is lifting it from beneath with their hands, the media in the bag will shift. Once they set down the material, the employee may then have to straighten out the bag to sit flush on a pallet or production line.

With a vacuum lift, we are lifting the material from above. That means that the materials will settle more in the natural shape of the container. Also, the employee can control a vacuum lift with one hand and guide the material with the other. This means that there is less need to set the material down and THEN adjust how it sits. One less step for the employee, which means faster handling for production.

The other reason  this matters is  we need to be flexible about  how we can grab the bag depending on how it is presented to the vacuum lift. We overcome this by manufacturing suction feet designed specifically for bags.

We have two kinds of suction feet that come in a wide variety of shapes and sizes. One item has a foam gasket which conforms to the shape of the bag, and the other uses a skirt that parachutes around the suction head and then conforms to the bag shape to create a seal. The type of foot used depends on the material/rigidity of the bag and how densely packed the contents are within the bag. As a general rule, bag feet with skirts work better with loosely packed bags whereas the foam gasket tends to be a more efficient method where it can be reliably deployed.

Center of Gravity can Shift

Next, let’s examine another challenge of having a container that can change shape when contents move the center of gravity can move as well.

Let’s look at the example of a 50 lb. bag. When an employee was asked to demonstrate how they would manually handle a bag, they bent over to reach the bag on the floor. They went to the end of the bag and used the center of gravity from their core to lift it. Before they were even upright with the bag, they were bending and leaning awkwardly. By relying on their center of gravity and leaning awkwardly, they weren’t bending their knees properly and were putting strain on their back as they lifted the bag to a conveyer. A repetition of this motion for a long period of time could endanger the health of their back.

No Easy Place to Grasp by Hand

With a side-by-side comparison of a bag and a box, it’s clear why a box is easier to grasp. It has hard corners and has more structure with which you can control the container. If material starts to shift in the bag, the bag shape changes, the center of gravity changes, and now you need to correct the load by shifting it back towards you. In a box, you have more structural leverage. With a bag, you do not.

But when you use a vacuum lift, this becomes a non-issue, since you are not handling the bag yourself. The suction head just needs to touch one surface, and you are good to go.

Media Density

Handling your bag can depend on how densely it is packed. Very densely packed bags move more uniformly. Less densely packed amplify the previously mentioned points  the center of gravity can become less predictable, and the shape or form of the bag can be quite varied. From a manual handling perspective, loosely packed bags are the hardest to manage.

In terms of using a vacuum lift to handle loose bags, there is a certain challenge associated. Material can bind or produce additional leak points due to the material getting in its own way.

For materials such as this, we offer a cam cleat gripper. It can be attached to the top of a loosely packed bag by opening and closing the gripper. This tool is also useful in applications in which you intend to pour or empty a bag while it’s still being lifted by the vacuum lifter.

Material of the Bag

There are three main materials of bag that we see at TAWI – paper, plastic, and jute or burlap.

These all have the aforementioned manual lifting challenges but jute or burlap bags have an added challenge for our vacuum lifts due to the porosity of the material.

We need good suction on a bag to handle it in our traditional methods, and as you can see in this picture, the burlap is so porous it is almost semi-transparent.

At TAWI, we have a special attachment for our lifts, which is called a Jute Hook, and it solves this porosity challenge.

What to do if You are Experiencing an Issue Handling Industrial Bags or Sacks

If you are looking to solve a bag lifting challenge, please fill out the form  here to connect with an application expert from TAWI. We will help you identify, test, and commission a solution that can be installed quickly (may times part of a day) and have your operators trained in minutes, not days or hours.