Pallet Wrapping Techniques

In modern distribution centers, stretch wrapping is by far the most common and desirable pallet securing method. Stretch wrap materials entered the warehousing world in the 1970s and have evolved into the preferred choice for wrapping pallets. With this evolution came automation. Some small distributors still use manual stretch wrapping on their pallets, but large-volume businesses now mechanize their stretch wrapping techniques.

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The American pallet industry is massive and ever-growing. An estimated 1.4 billion pallets actively circulate daily within the continental United States. This figure doesn’t include the millions of loaded pallets destined for intercontinental shipping. The NWPCA’s slogan is Pallets Move the World, and most of those pallet loads containing an estimated $400 billion in U.S. trade are stretch wrapped.

Stretch Wrapping Supports Efficient Pallet Shipping

To meet the demands of an enormous pallet industry, the stretch wrap and stretch wrap machinery business is equally massive. Reports indicate that stretch wrap consumption will increase 3.5 percent during 2019 and account for $3.1 billion in sales. Pallet wrapping equipment sales are also booming. Persistence Marketing Research calculates that purchases of semi-automatic stretch wrappers, automatic stretch wrappers and robotic pallet wrappers will achieve $1.35 billion in worldwide annual sales over the next half-decade.

The struggle of manual versus automatic stretch wrappers is clearly in favor of mechanized options. Stretch wrapping a pallet by hand is not economical for companies handling multiple pallets per day. The price to pay in employee fatigue and injuries from excessive manual pallet wrapping is simply too high to pay. That’s why forward-thinking warehouse managers and operators heavily invest in mechanized stretch wrappers. They also make the time investment to teach their workers proper stretch wrapping techniques.

Stretch Wrapping Basics

Experienced warehouse workers know there’s no universal way to stretch wrap a shipping pallet. Too many variables occur in different load configurations and contents. However, certain principles apply to stretch wrapping a pallet — just as there are pros and cons when discussing manual versus automatic pallet wrapping.

Before getting too far into the specifics of proper stretch wrapping techniques, it’s important to know a few basic things about stretch wrap material. The most common stretch wrap plastic is made of linear low-density polyethylene (LLDPE). This is a complex chemical film that excels in superior elasticity. Depending on its gauge or thickness, this versatile material can expand up to five times its inert length without breaking.

LLDPE is a stretchable super-film. Since arriving on the warehouse market, LLDPE stretch wrap products truly revolutionized the material handling business. Today, chemistry and technology has improved LLDPE products and divided them into these two primary categories:

1. Cast LLDPE film: Cast film is the most common stretch wrap material and the least expensive to make. Manufacturers produce cast film from a highly heated liquid plastic base, pass it through a precise slot and out onto cooling rollers. This is a quick and inexpensive process and produces a film suitable for light- to medium-duty pallet wraps. Cast stretch wraps are usually clear and glossy with easy unwinding characteristics. They have consistent cling quality and uniform thickness.
2. Blown LLDPE film: Blown stretch wrap has a different manufacturing method. Instead of casting liquid plastic through a slot or die and then roller-cooling it, stretch wrap manufacturers inject hot air into the liquid resin and blow it into a bubble. This produces a tougher stretch wrap more suitable for medium- to heavy-duty loads that need strong stretch wraps.

Blown LLDPE stretch wrap is more expensive to manufacture than cast film and costs more to the warehouse purchaser. For daily operations, distribution centers resort to cast wrap for most pallet shipments. When it comes to heavy and sensitive loads, it's good insurance to pay the extra and wrap pallets with blown film.

Understanding proper stretch wrap techniques starts with knowing other differences between stretch wrap types besides their manufacturing processes. Technical issues should also be considered.

The following list describes the main differences between cast versus blown wraps that affect proper stretch wrapping techniques:

• Strength: Blown wrap is much stronger than cast film when equally compared by thickness or gauge. Blown wrap is less likely to accidentally tear when snagged on a sharp edge.
• Film yield: Yield refers to the film’s breaking point. Blown wrap has a higher yield point than cast and can stretch well beyond its 200 percent design capacity before snapping.
• Film memory: This refers to the film's permanent elastic qualities. In other words, how well does the film resort to its original and inert state? Blown stretch wraps have a better memory capacity than cast products, which makes them better-suited for tough applications.
• Load retention: Cast film's weakness is that it will continue to stretch after applied. That’s not the case with blown film, since, once it’s put in place, blown wrap will not keep stretching.
• Puncture resistance: This is different from strength, yield or memory. Blown wrap is far more resistant to punctures and cuts from sharp objects than cast film.
• Visual clarity: Here’s an area where cast wrap beats blown film. If a shipper wants the pallet contents to be visible, cast film is more transparent than the natural opaqueness of blown stretch wrap products.
• Rewind noise: Because blown wrap is tougher and more durable than cast film, it’s also noisier when unwinding from its spool. Cast stretch wrap is virtually silent to apply.
• Film cling: This is a final but important difference. Blown stretch wrap has one-sided cling, whereas cast wrap will cling on both faces. While pallets wrapped with blown film will never stick to each other, that’s not the case with cast-wrapped loads.

Pallet sticking can be annoying for warehouse people who have large and fast throughput. However, with proper pallet wrapping techniques, stick annoyance can be minimized. Other problems can also be avoided by using proper pallet wrapping techniques.

Proper Pallet Wrapping Techniques

Many proven and practical techniques for stretch wrapping pallets exist. These techniques apply whether using cast or blown film. They also apply whether hand-wrapping pallets or using semi-automated or automated systems such as turntable stretch wrappers, overhead stretch wrappers or robotic/automatic stretch wrapping machines.

It’s worth repeating that professional pallet wrappers with years of experience agree there’s no universal way to stretch wrap a pallet. Proper pallet wrapping techniques have common procedures. However, technical fine points depend on the load type being prepared for shipment. These are three basic pallet load configurations or profiles common to the material handling industry:

• A-profile load: The most common load profile is stacked uniformly from the pallet’s bottom to the top. The A-profile load footprint is a similar size to the pallet shape, and the product stacks have a consistent shape with no irregularities or protrusions. These are the easiest load profiles to secure with stretch wrap.
• B-profile load: This pallet load configuration has a footprint smaller than the pallet dimensions or inbound from the pallet base. B-profile loads also have irregular shapes and vary from wide to narrow as they extend upward. Stretch wrappers find B-profile loads challenging to secure due to inconsistent surface alignment.
• C-profile load: C-profile pallet stacks are the opposite of B-profiles. In this configuration, the lower layer is larger than the pallet dimensions. The material overhang presents a real problem for wrappers, since the low point where the load meets the pallet frame is the most crucial connection.

Wrapping patterns, or wrapping techniques, are fundamental to ensuring a stabilized pallet load. An untold value of damaged or destroyed goods is lost every year from insecure or improper pallet wraps. This doesn’t need to happen if warehouse workers are trained in effective pallet wrapping techniques and practice these seven main steps to pallet wrapping perfection:

• Step 1 — Pick the pallet: It’s critical to pick the right pallet. Proper pallets are the right size for the load. They should be made of the proper material and be in good condition. Proper pallets also are capable of supporting the intended weight. Experienced material handlers who thoroughly know their techniques try to make their load as close to an A-profile shape as possible. Because the base if the critical attachment point, it’s best to have the product’s bottom layer as close to flush with the pallet frame as possible.
• Step 2 — Choose stretch equipment: It’s also critical to choose the right stretch wrapping equipment. For light and occasional pallet wraps, some material handlers prefer to hand wrap their pallet loads. This becomes burdensome when warehouses are continually shipping out big loads. For large and repetitive shipping, warehouse handlers defer to a mechanical stretch wrap machine. The basic stretch wrapper is a semi-automated turntable model. Overhead machines are the next step in semi-automation followed by robotic wrappers, which are fully automated.
• Step 3 — Secure the film to the pallet: Wrapping starts at the bottom and spirals upward toward the top. It’s vital to fix the leading end of the film to the pallet base before wrapping. Most stretch wrapping technicians begin by twisting the film into a rope-shape with a tail approximately two feet long. They weave this into the pallet slats to provide a grip, but they don’t bother to physically tie it. The film’s cling factor will keep the tail in place without needing to be knotted. Not tying a knot also saves time for whoever unpacks the loaded pallet.
• Step 4 — Wrap the product: Begin a 360-degree wrap starting with full coverage of the product load to the pallet base. Most experienced stretch wrap operators make two or more circles around the base to make sure there’s sufficient grip anchoring the load to the pallet frame. Next, the technique involves making 50-percent material overlaps as the wrap moves upward. If hand-wrapping, you'll need to eye-ball it. Automated stretch wrappers can be set for specific overlap coverage, and the operator has full control over how much material they use on a specific wrap job.
• Step 5 — Control wrap tension: Going hand-in-hand with step 4, tension is a highly important stretch wrapping technique. Tension controls how tightly the load is compressed. This varies depending on a crush factor where sensitive products need light tension in relation to the wrap’s stretch factor. Heavy and solid loads will withstand greater tension, and this is a key element in making sure the load is packed as tightly as possible. It’s difficult to apply an even tension force when hand wrapping. Machine stretch wrappers, on the other hand, have a uniform force due to their pre-set instructions.
• Step 6 — Decide whether to double-wrap: Stretch wrap operators have a choice to make when they reach the top of their upward spiral. That’s whether to “tie-off” the wrap on top of the load or reverse course and spiral downhill. This decision truly depends on the load type they’re securing. “Double-wrapping," as it’s known in the warehouse and material handling business, is a precaution taken based on individual judgment. Follow the rule-of-thumb — when in doubt, always double-wrap. This safety measure consumes more stretch wrap film, but it can save against lost product.
• Step 7 — Tie off the wrap: The final step in executing a proper pallet wrapping technique is tying off the wrap. Once a material handling worker is satisfied that they have a secure load that’s going to withstand shipping, they sever the film from the spool. Now they have a choice to make. They can literally tie the wrap end to the load, whether that be to the top or the bottom. Physical tying creates a knot which consumes time on both the shipping and receiving ends. Most experienced stretch wrappers simply tuck the severed wrap end into a seam. The film’s cling factor and the seam’s compression firmly hold the tie-off in place without worry that the stretch-wrapped load could unravel.

Properly wrapping pallets ensure that products are shipped safely and with minimized loss of inventory — saving you time and money.

Stretch Wrapping Pallets Manually

Although the majority of commercial and industrial warehouses that handle pallets daily use semi-automated turntables and overhead stretch wrapping machines as well as robotic/automated stretch wrappers, some businesses still choose to manually wrap. However, few businesses elect to hand-wrap pallets if they pack, wrap and ship in large quantities. It’s simply not economical to stretch wrap large pallet amounts by hand.

An economy of scale applies when companies choose to machine-wrap their shipments. Manually stretch wrapping is a time-consuming affair. It’s slow and tiresome. It’s also hazardous for the workers, since the strain put on lower backs and limbs significantly increases the likelihood of muscular-skeletal injuries. Worker compensation claims stemming from manually stretch wrapping could easily outweigh the cost of investing in modern and professional stretch wrapping equipment.

Manually wrapping pallets is also ineffective at properly securing loads to pallets. Workers hand wrapping can’t achieve the same tension and uniformity on their film that a wrapping machine can. Manually wrapping a pallet increases the likelihood that a load will shift or break apart in transit. Taking into account the rule-of-thumb that manually wrapping pallets decreases efficiency when packing more than 15 pallets per day, it’s much more cost-effective for warehouses to invest in stretch wrapping machinery.

Investing in Turntable, Overhead and Robotic Stretch Wrapping Equipment

Larger volume shippers find that investing in mechanized stretch wrapping equipment is much faster and safer. Because of this increased efficiency, warehouses that use automatic stretch wrapping machines also benefit from cost-savings. Consider these benefits that stretch wrapping machines offer:

• Automation uses less film due to tighter tension.
• Tighter tension increases load security.
• Products are better protected and less vulnerable to theft or damage.
• Automated wrapping is uniformly consistent and more presentable.
• Quality control improves with mechanized wrapping.
• Labor costs decrease and production efficiency increases with machinery.
• Warehouse worker safety significantly improves with stretch wrapping equipment.

The benefits of investing in stretch wrapping equipment are clear. There’s no doubt that mechanized stretch wrappers make a warehouse environment safer and more efficient. They also add value to shipments by making them secure and visually pleasing leading to increased receiver satisfaction.

The issue for most warehouse managers or product procurers is deciding in what type of stretch wrapping equipment to invest in. The warehouse and material handling equipment market boasts a lot of inventory and wrapping equipment types. Primarily, suppliers divide stretch wrappers into two main categories — semi-automated and fully automatic machines.

However, experts in the stretch wrapping machine supply chain divide their mechanized inventory into three distinct areas. Those are turntable stretch wrappers, semi-automated overhead wrappers and robotic/fully automated stretch wrapping equipment. Here’s a closer look at the three types of stretch wrappers:

• Turntable stretch wrappers: Turntable stretch wrappers are basic material handling equipment pieces. They’re the simplest design of all wrapping machines, and they’re the easiest to use. Turntable models are also the least expensive of all stretch wrappers, making them a good investment for smaller warehouse operations with limited throughput. Turntables function by placing a loaded pallet on the machine’s base platform, which is a revolving turntable. The principle is similar to a vinyl disc record player. As the pallet slowly turns, the stretch wrap extends from its storage spool and surrounds the pallet until it’s sufficiently secure.
• Overhead semi-automatic stretch wrappers: Overhead stretch wrappers are slightly more sophisticated than turntable wrapping machines. Instead of the pallet revolving as it’s being wrapped, the pallet remains stationary on the machine’s platform. The overhead mast containing stretch wrap film revolves around the pallet extending wrap and tensioning the load to specifications. Many overhead stretch wrappers have semi-automated features that take the guesswork out of tension, overlap and number of plies required to safely prepare a loaded pallet. Overhead stretch wrappers are more expensive than turntable models, but they make up for the cost through increased productivity.
• Robotic/Fully Automated Stretch Wrappers: Robotic stretch wrappers are exactly as their name sounds. They are robotically programmed to automatically receive pallets on their platform and stretch wrap them to precise preset specifications. Most robotic/fully automated machines work best in large applications where conveyor systems feed loaded pallets straight to the wrapper’s work platform. These complex pieces of equipment need little human supervision, which greatly reduces labor costs. Although robotic/fully automated stretch wrappers are expensive, their payback is enormous. For big warehouse operations with large-volume throughput, robotic stretch wrappers are a sound investment.

For most warehouses and companies that ship large volumes of product, choosing a semi-automated or fully automatic stretch wrapper is a cost-effective investment.

Five Best Tips for Effective Stretch Wrapping

Stretch wrapping machines make pallet loading easy. Experienced material handling employees who work with stretch wrappers daily know some trade secrets about effective stretch wrapping. Here are five of their top tips:

1. Start with a proper pallet. A wrapped load is only as good as its foundation, and a good pallet is critical for best results.
2. If possible, design the load to an A-profile. Even product loading is much easier to effectively stretch wrap than offset loads.
3. Place heaviest products on the pallet’s bottom. This avoids making the load top-heavy and prone to tipping.
4. Use the right stretch wrap film for the particular load. This is a key to performance as the wrap must be strong enough to hold the load but not so excessively strong that it will crush sensitive contents.
5. Train workers to safely use the stretch wrap equipment. Safety starts with knowledge and never ends. Knowledgeable workers are safe workers.

Compared to manually wrapping pallets by hand, stretch wrappers are a godsend for warehouse workers and managers who strive for consistency in load performance, protection of products and making pallet wrapping safe for everyone involved.

Stretch Wraps Versus Shrink Wraps

Many people confuse shrink wrapping with stretch wrapping. The terms sound similar, but that’s where it ends. Shrink wrapping a pallet involves an entirely different film material that responds to heat to tighten around the load, not tension pulled on the load, as is the case during stretch wrapping. Knowing how to shrink wrap a pallet is a different skill set than operating a stretch wrapper.

Make Cherry’s Industrial Equipment Your Stretch Wrapping Partner

When you’re exploring your equipment options for the right turntable, overhead or robotic stretch wrap machine, make Cherry’s Industrial Equipment your first stop. Partner with us for proven results. Cherry’s is a leading American material handling equipment supplier, and we’ve been in the business for more than 35 years.

Cherry’s Industrial Equipment has the latest models of turntable, overhead and robotic/automatic stretch wrappers. We can also customize stock stretch wrappers to suit your unique warehouse needs. Whether you’re a large conveyorized operation or a small-throughput company, Cherry's expert support team will make your pallet loading tasks safe and easy.

Contact Cherry’s Industrial Equipment today to learn more about stretch wrapping machines and other top-quality material handling machines. Call us at 800-350-0011, or reach us any time through our online contact form.