There are a number of factors involved in successfully stacking bulk bags.  The one most overlooked is that your filled bulk bags must have a flat top!

Most dry bulk solids have an angle of repose.  If you pored a handfull of your product on a flat surface it would form a peak.  The angle of the peak with the horizontal varies depending on the properties of the product.

When product is poured into a bulk bag it forms a peak just the same as the example above.  However, if you plan to stack bulk bags it is critical that your bulk bag filling equipment densifies the product enough to produce a flat top.

A filled bulk bag with a flat top provides a stable platform on which to stack.  Without it, the odds of a leaning or falling stack are greatly increased.

If you are stacking bulk bags or plan to, safety is the first priority.  Make certain that your bulk bag filling equipment can produce a flat topped bag before you do anything else!

See how Control and Metering's cone table densifiction technology produces flat topped bulk bags!

In previous posts we have discussed reducing shipping costs and the benefits of replacing or eliminating pallets.

In this week's post let's discuss all of the ways that the cost of bulk bag packaging can be reduced.

1. Reduce bulk bag size.  Reducing the height of a bulk bag by 10% decreases its price by roughly 5%.  Maximum densification, for example using the cone table densification system, can almost always decrease bag height by 10% - sometimes by as much as 40% or more.
2. Eliminate baffles.  If your bulk bags have internal baffles and they are being used to enhance stability, it is highly likely you can eliminate them by using a densification system designed for maximum results.  Getting rid of baffles can save as much as $5 per bag.
3. Use coated bulk bags.  If you use liners in your bulk bags you may be able to eliminate them and use coated bulk bags instead.  See the blog post "Bulk Bag Liners - When To Use Them... or Not!" for an excellent review on when to use liners and when not to.  Switching from a liner to a coated bulk bag can save as much as $2 -$3 per bag.
4. Replace wooden pallets with plastic channels.  Using plastic pallet replacement channels can reduce direct packaging cost and logistics related costs too.  See the blog post "Eliminate Wood Pallets - Ship Bulk Bags Without Wood Pallets" for details.
5. Eliminate wooden pallets.  Properly designed and filled bulk bags can be handled only by using their lifting loops thereby eliminating pallets - and their cost - completely.  See the blog post "Pallet Free Bulk Bag Handling" for details.

As you can see from there are numerous ways to significantly reduce the cost of your bulk bag packaging.

How can bulk bag users reduce shipping costs?

The bulk density of your product determines the opportunity for shipping cost savings.

If your product is heavy enough to weigh-out a shipping container/trailer then, as we have seen in the last two posts, replacing wood pallets with a plastic channel replacement system or simply eliminating bottom support altogether can significantly reduce shipping costs.  Reducing the weight of packaging per shipment means you can replace the weight reduction with product thereby shipping out more product per container and reducing shipping cost per pound.

However, if your product's bulk density is such that you can't weigh-out a container/trailer there is an additional step you can take to minimize shipping cost.

Bulk Bag Densification Increases Payload

Light products such as wood flour, fluff carbon black, fumed silica and the like react favorably to certain types of densification.  This means that the payload of a given size bulk bag can be increased.  Increasing the bulk bag payload increases the amount of product that be shipped per container thereby reducing shipping cost per pound.

Low bulk density bulk solids tend to trap air between their particles. Depending on the particle shape it can be very difficult to remove the air while the bulk bag is being filled. Bulk bag filler densification systems are designed to remove the trapped air thereby densifying the product.

Some densification systems are more effective than others. Carefully matching the method of densification with the product characteristics can result in a significant improvement in packed bulk density thereby increasing payload.

Bulk Bag Densification Reduces Shipping Cost

As a starting point it is reasonable to assume that a densification system capable of maximum compaction should be able to increase payload weight by a minimum of 10%.

Control and Metering's experience is that payload increases of 20-30% are often achievable and in some cases as much as 40%+ more weight can put in a bulk bag that has been previously filled without densification or with ineffective densification systems.