Pallet loads can come in a variety of shapes, sizes and weights. Each load can be categorized into one of three different load profiles. A, B or C loads are used to describe and class a load based on its size, uniformity, stability and edge profile.
Over the years, the stretch wrap industry has engineered new equipment and films optimized for each type of load. By using the right equipment and the right film, pallets can have increased stability and containment while reducing film breaks and punctures.
Types of Loads
There are three types of load profiles that are classed as A, B or C loads.
A-loads are the most common load seen today. These loads consist of uniform boxes that are the same dimensions and weights. This load features uniform edges, both vertically and horizontally, that have no protruding edges. This limits the risk of the palleted boxes tearing or puncturing the film as it's applied. The load's uniformity is consistent even with the pallet it's stacked on. A proper A-load will have a footprint that almost matches the pallet deck exactly.
B-loads are not quite as uniform as their class A counterpart. These loads don't have the consistent edge profiles of an A-load, but still, hold some uniformity in shape. A B-load is built from inconsistent boxes and may result in some minor edges that can catch, or snare stretch film as it is applied. A palletized B-load will also often feature a load footprint that doesn't match the pallet deck.
C-loads are loads that have the highest risk of causing tears and punctures during the wrapping process. C-loads are unique and no c-load will have the same edge profile as another. These unique and uneven edges make C-loads the most likely load to cause stretch film tearing or puncturing. A uniform load may also be marked as a C-load if it is very heavy, light or has poor weight distribution making it unstable. These loads difficult to handle and often require special equipment to wrap without causing a pallet collapse.
How to Find the Best Stretch Film For Your Load Type?
Stretch wrap film is available in a variety of styles and gauges. But how do you determine the film that is the best suited for your load? The first thing to determine is your required containment force. Containment force is the force created by pre-stretching the film through the stretch wrapper carriage allowing the film to hold the load together and lock it to the pallet. Once you know your required containment force, you are able to determine what gauges of film you can use. Film gauge can be increased or decreased depending on how many wraps are going to be used.
The two main differences in the types of film that can be used per load are when we consider cast film and blown film.
Cast Stretch Film vs. Blown Stretch Film
Blowing heated resins into a bubble produces blown stretch film. The bubble is then transformed into sheets that a rolled and applied to a core tube. Blown stretch films provide users with a softer, more pliable film. The increased pliability helps to reduce the risk of film breaks and punctures. The flexibility of the film creates a film memory, helping it maintain its original shape when the load shifts and moves.
Cast films are manufactured by feeding heated resins through a line of cooled rollers. The rollers cool and solidify the film, which is then cored and cut into the proper roll sizes. Cast film offers a cost saving over a blown film of the same type due to a lower manufacturing cost. Cast films create strong containment forces but do not provide the same pliability as blown films. This makes cast films more susceptible to tears and punctures during the wrapping process.
What Stretch Wrapper is Best for Each Load Type?
The type of stretch wrapper used is often just as important as the film being used. Using the right stretch wrapper can improve wrapper throughput levels and increase stretch film efficiency. The right wrapper also improves product and employee safety, providing the most stable wrapping environment for you palleted loads.
Turntable Stretch Wrappers
Turntable Stretch Wrapping machines use a rotating platform to turn your pallet in place. A mechanical arm applies the stretch film ensuring an even application. Due to the turning base, turntable stretch wrappers require a steady, stable load. This makes them the optimal packaging method for steady, stable loads with wrapping volumes estimated between 20 and 40 loads per hour.
Rotary Arm Stretch Wrappers
Rotary Arm Stretch Wrap Machines keep your load stationary while a mechanical arm rotates around the load. Rotary arm stretch wrappers can be installed in a wrapping area or as an integrated part of an automated packaging line. These high-performance wrappers offer incredible speeds and are best suited for high volume packaging facilities. This method is the optimal wrapping method for tall or oddly weighted loads that have a high risk of collapse.
Find the Right Film and Stretch Wrapper for Your Load
Determining which type of stretch wrapper and stretch film is right for your load is key to creating an efficient and effective packaging line. You will need to consider your load profile, weight, and estimated throughput levels before making your decision. Our expert Packaging Specialists have the expertise to test loads and discover the best film and equipment combinations.