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A palletizer is a mechanical system used to stack and organize various products into one cohesive load, thus improving efficiency in handling, storage, and transportation. Often, it is part of a larger packaging operation, which might include functions like weighing, counting, sorting, labeling, metal detection, and wrapping. These additional processes can sometimes be included within the palletizer or handled with different equipment.
Palletized products form a unit load by bundling materials for streamlined handling. It is generally quicker and more economical to move a single large unit rather than numerous smaller items. Typically, finished goods aren't made for individual shipping but are placed in boxes, cases, trays, or crates, then consolidated into a single load supported by pallets or roll cages. The packaging forms represent secondary unit loads, with roll cages identified as tertiary unit loads.
The palletizer arranges products onto a pallet, hence the term. Pallets are level, sturdy platforms crafted from wood, plastic, paper, or metal featuring notches or openings. These features accommodate forklifts and hand pallet trucks for lifting and relocating the load. These openings designate a pallet as either two-way or four-way, indicating forklift entry directions. Most pallets can support loads up to one metric ton over an area close to one square meter. Below are examples of standard pallet dimensions.
| Dimensions (W x L) in millimeters |
Dimensions (W x L) in inches |
Unused Floor Space (ISO Container) |
Region |
| 1016 x 1219 | 40.0 x 48.00 | 3.7% | North America |
| 1000 x 1200 | 39.37 x 47.24 | 6.7% | Europe, Asia |
| 1165 x 1165 | 45.9 x 45.9 | 8.1% | Australia |
| 1067 x 1067 | 42.00 x 42.00 | 11.5% | North America, Europe, Asia |
| 1100 x 1100 | 43.30 x 43.30 | 14% | Asia |
| 800 x 1200 | 31.50 x 47.24 | 15.2% | Europe |
Some palletizers are equipped to stack products using slip sheets or conveyor surfaces and are called unitizers. These unitized loads eliminate the need for a pallet. In some instances, "palletizers" and "unitizers" are interchangeably used terms.
There are three main types of pallets made from wood or plastic, and one type made from cardboard.
The most prevalent is the GMA pallet, typically measuring 40x48 inches, with notches on the sides facilitating side lifting access.
The CHEP pallet ranks as the second most used. This design, also usually sized 40x48 inches, incorporates blocks on every side, making handling possible from any direction. These pallets are easily recognized by their distinctive blue color.
PECO pallets are emerging in the industry, providing similar services as CHEP. They are known for their red paint identifiers.
The Pull Board is characterized by a corrugated sheet with dual 3-inch tabs generally located on adjacent sides. Forklifts equipped with special attachments can use these tabs to push or pull loads on or off the prongs. Pull Boards are favored for their hygiene benefits and space efficiency, allowing up to an additional 5 inches of space per load, potentially saving significant costs by accommodating additional layers in a transport vehicle.
Certain palletizers are engineered to stack items on slip sheets or conveying surfaces, termed unitizers. With unitized loads, there's no requirement for a pallet, and in some applications, the terms "palletizers" and "unitizers" are used interchangeably.
Diverse companies may demand various pallet arrangements tailored to their specific requirements.
This stacking arrangement strengthens load integrity with a foundational column that bolsters the whole pile. In warehouses, pallets can be stacked up to four units high, leveraging load strength from the vertically aligned box corners. The top interlocked section adds further stability, ensuring unwrapped loads can be safely maneuvered with a forklift to a wrapping station.
Before the advent of automatic palletizing systems, warehouses and distribution centers relied heavily on manual hand stacking to organize products into pallet loads for storage and shipping. This method of manual palletizing was extremely labor-intensive and time-consuming, with workers expending considerable physical effort to achieve relatively low throughput. As global commerce expanded and supply chain efficiency became a top priority, the need for optimized material handling solutions became increasingly apparent. The adoption of pallets and pallet handling equipment revolutionized logistics in the early 20th century, particularly during World War II, when rapid and reliable transport of heavy loads became critical for military and industrial supply chains.
The introduction of the first mechanical palletizer by Lamson Corp. in 1948 marked a major milestone in warehouse automation technology. This early row-forming palletizer was designed to automate the process of arranging products—such as cases, cartons, bags, or boxes—into rows. These rows were then systematically transferred to a stacking area, where each new layer was placed upon the previous one until a complete pallet load was constructed. Compared to manual operations, this innovation greatly increased both throughput and consistency, setting the stage for future advancements in automated palletizing equipment and machinery.
With the rise of high-speed production and distribution demands in the 1970s, the material handling industry introduced the in-line palletizer. Unlike traditional row-forming palletizers that relied on intermittent movement, in-line palletizers utilized continuous product flow technology. This enabled the precise orientation and positioning of products onto layer-forming platforms, significantly boosting line efficiency and reducing bottlenecks. In-line palletizers are especially valued in industries such as food and beverage, consumer packaged goods, and manufacturing, where rapid end-of-line automation is essential for scalable operations.
The 1980s brought further innovation with the development of robotic palletizers, a major leap forward in automation and versatility. These advanced palletizing robots employ articulating arms equipped with end-of-arm tooling (EOAT)—such as mechanical grippers, vacuum suction grippers, or magnetic devices—tailored to handle a diverse array of packaging types and product sizes. Robotic palletizing systems facilitate flexible operation, fast changeovers, and precise stacking patterns, making them ideal for environments with high product variability or custom palletizing requirements. The widespread adoption of robotic and automated palletizing solutions has since transformed modern warehouses, distribution centers, and manufacturing facilities, leading to greater productivity, improved worker safety, and enhanced supply chain optimization.
Today, the evolution of palletizer technology continues with the integration of smart sensors, machine learning algorithms, and cloud-based warehouse management systems. Advanced automatic palletizers and robotic palletizing solutions now offer real-time data tracking, predictive maintenance, and seamless connectivity with upstream and downstream automation for enhanced operational efficiency. As e-commerce, just-in-time delivery, and global trade accelerate, investing in state-of-the-art palletizing systems is increasingly essential for businesses aiming to minimize costs, reduce manual labor, and stay competitive in the rapidly evolving materials handling industry.
Palletizers, essential automated machinery in materials handling and packaging lines, are typically categorized into two primary types: conventional palletizers and robotic palletizers. Both conventional and robotic palletizers are engineered to efficiently receive, organize, and stack products onto pallets at both high- and low-elevation entry points. High-level infeed elevations usually range between 84" to 124", while low-level infeed heights typically span from 30" to 36". Within the group of conventional palletizers, two main subtypes exist: floor-level (low-level) palletizers and high-level palletizers. Understanding the differences between these types is crucial for optimizing warehouse automation, streamlining order fulfillment, and improving supply chain efficiency.
Floor-level palletizers, sometimes called low-level palletizers, feature an infeed conveyor elevation of 30" to 36". As products such as cartons, cases, or bags travel along the infeed conveyor, a turning device or specialized conveyor system ensures correct orientation. The items are then moved into the row-forming area, where they are grouped into orderly rows. Once a complete row is assembled, it transfers to the layer-forming section. When an entire layer is organized, it moves forward to the stripper plate for height adjustment and precise placement onto either the pallet or the previous product layer. Throughout palletizing, the pallet stack remains stationary to ensure stability and safe loading, which minimizes product damage. Once the pallet is fully stacked, it is transferred to the discharge conveyor, commonly set at an 18" height for easy removal and further processing.
Floor-level palletizers are generally more affordable, cost-effective, and simple to construct compared to their high-level counterparts. Their compact design requires less floor space, making them ideal for facilities with space constraints. With all key components positioned at ground level, these automatic palletizing machines offer fast, straightforward preventive maintenance and troubleshooting due to excellent access to wear parts. Operators can securely and easily monitor the palletizing process at eye level and make real-time adjustments as necessary. Integration with other packaging machinery—such as case erectors, packers, case sealers, and stretch wrappers—is seamless because floor-level palletizers eliminate the need for complex elevation changes to the infeed. This makes them particularly well-suited for packaging lines focused on optimizing throughput, improving productivity, and reducing labor costs for low- to moderate-speed palletizing applications.
High-level palletizers are engineered for high-speed, high-volume palletizing operations, with infeed conveyor elevations typically between 84" and 124" or more. Similar to floor-level types, products—including cartons, cases, trays, or shrink-wrapped bundles—are transported on the infeed conveyor to a turning or orienting device, ensuring the correct configuration for downstream processing. After orientation, products move to the row-forming area, where they are grouped into precise rows and transferred to the layer-forming platform. Once a layer is complete, the layer is then advanced onto the pallet or stacking platform. Unlike floor-level palletizers, high-level systems usually feature stack-raising and lowering mechanisms, allowing each new layer to be added efficiently regardless of stack height. Following completion of the entire stack, the platform lowers the finished pallet to the discharge conveyor, which is installed at heights from 18" to 30", readying the load for downstream operations such as shrink-wrapping or forklift transport. Raised operator platforms are frequently constructed to provide clear visibility and enhance operator ergonomics in monitoring complex, high-speed operations.
High-level palletizers are preferred in manufacturing and distribution environments with adequate overhead clearance for inclined conveyors and where the packaging line requires high throughput. Their advanced design supports rapid product transfer and demanding material handling requirements, efficiently managing speeds of approximately 40 to 50 units per minute or more—regardless of the discharge height from preceding process equipment like packers or case sealers. This makes high-level models optimal for large-scale warehousing, beverage bottling, food processing, and fast-moving consumer goods (FMCG) industries, where automated pallet load integrity, precise pallet patterns, and continuous high-capacity operation are essential. When considering ROI, high-level palletizers deliver greater line efficiency, maximize space utilization, and accommodate a wider range of product formats, which is valuable for businesses planning for future growth or flexibility in their packaging automation strategy.
When evaluating which type of conventional palletizer best suits your facility, consider key selection criteria such as product type and dimensions, desired palletizing speed, available floor and ceiling space, integration with existing automation (such as stretch wrappers, labelers, and conveyors), ease of maintenance, energy efficiency, and total cost of ownership. Consulting with a palletizer manufacturer or packaging automation specialist can help determine which system is best aligned with your production goals, whether you prioritize lower capital investment and ease of integration (floor-level) or high-speed performance and scalability (high-level). This ensures that your investment in automated palletizing delivers maximum efficiency, safety, and product protection for the long term.
A palletizer is a mechanical system that stacks and organizes products into unit loads on pallets. This streamlines product handling, storage, and transportation as part of automated packaging operations.
Floor-level palletizers have low infeed conveyors (30"–36"), are compact and easy to maintain, while high-level palletizers use elevated infeed conveyors (84"–124") for high-speed, high-volume operations, often in manufacturing and distribution centers.
Common pallet types include GMA, CHEP (blue), PECO (red), and Pull Board pallets, each with different construction and handling features to suit various industrial applications.
Palletizing began with manual stacking, advanced to mechanical palletizers in 1948, then in-line palletizers in the 1970s, and robotic systems in the 1980s, now integrating smart sensors and machine learning in modern automated solutions.
In North America, common pallet sizes are 1016x1219 mm (40x48 in) and 1067x1067 mm (42x42 in). Europe uses 800x1200 mm (31.5x47.24 in) and 1000x1200 mm (39.37x47.24 in). Asia utilizes 1100x1100 mm (43.3x43.3 in).
Unitizers stack products into unit loads using slip sheets or conveyor surfaces instead of pallets. The terms "palletizers" and "unitizers" are sometimes used interchangeably, especially when no pallet is required.
A conventional palletizer consists of various components, including both static and moving parts. Some of these components may be integrated directly into the palletizer, while others can be installed as separate pieces of equipment.
Bags exiting the packaging units and sewing machines are typically in an upright position. They are then positioned or flattened by the knockdown conveyor to prepare them for palletizing.
This can be either an integrated or separate machine used to ensure the accuracy of the weights of bagged products prior to storage and distribution.
Similar to the checkweigher, this device can be integrated with the palletizer or operate as a separate machine. The metal detector identifies any ferrous, non-ferrous, or stainless-steel contaminants in the product.
Products that are detected as either being off-weight or containing metal contaminants are diverted by the reject conveyor to a staging area or platform.
Products can enter a palletizer from different sides, including the side, rear, or front. These infeed types apply to both floor-level and high-level palletizers.
To ensure the pattern is formed correctly, the bag flattener adjusts and shapes the bags to the proper height.
As products are fed onto the palletizing machine via the conveyor, they are oriented into the correct position before entering the row-forming area. Various turning devices are used for this purpose, including turn shoes, cushioned turns, turntables, and soft turn devices. Turn shoes and cushioned turns gently nudge the product to rotate it by 90°. Turntables lift and rotate products by +90°, -90°, or 180°. Soft turn devices utilize two sets of rollers driven by variable frequency drives (VFDs) to achieve rotations of +90°, -90°, or 180° by varying roller speeds.
These mechanical devices are used to create the desired pattern in the row-forming area by establishing side-to-side gaps. Stops are activated by pneumatic valves and cylinders, which are controlled by programmable logic controllers (PLCs). To alter forming patterns, only software controls need to be adjusted, eliminating the need for hardware changes.
These mechanical devices, similar to stops, assist in pattern formation by creating front and back gaps. Once a layer is complete, it is transferred onto a stripper plate or apron, which then moves it onto the pallet. When the stripper plate is in place on top of the pallet or stack, a gate descends to block the layer's movement. The stripper plate is then retracted, leaving the layer in position on the stack. A pusher gate holds the layer in place until it is released.
This component enables the creation of front and back gaps without the need for a pusher gate. As the stripper apron opens in the middle, it forms gaps while the layer is placed onto the stack below.
As the name suggests, this component dispenses and conveys pallets to ensure the continuous operation of the palletizer. When one unit load is completed, the pallet dispenser feeds a new pallet. Typically, a pallet dispenser holds 10 to 20 pallets in its pallet magazine.
For some materials, such as bagged products, slip sheets are needed between layers. A slip sheet dispenser uses a venturi vacuum system to efficiently place these slip sheets.
This component transfers completed unit loads onto a platform, where they can be picked up by forklifts or hand pallet trucks for storage.
This is the control area where operators troubleshoot, adjust, or reprogram the palletizer and its automated components. The main element of the control panel is the PLC, which controls circuit functions according to the machine’s programming.
These palletizers utilize robotic arms to maneuver the end effector and perform pattern formation. Robotic palletizers are categorized into Cartesian, gantry, SCARA, and articulated types. Each type varies in flexibility and range of movement.
This type of palletizer has an end of arm tool that can move in three directions of space, or the Cartesian axes X, Y, and Z, hence the name Cartesian. Its mechanical structure consists of beams and a telescopic mast usually actuated by servo motors. This type of robotic palletizer is slow and is used for products with consistent weight and sizes. This is generally the cheapest type of robotic palletizer suiting single line speeds of up to 10 items per minute.
A gantry palletizer features an end effector assembly mounted on a beam that moves along one axis. The beam itself moves along a perpendicular axis, allowing for movement in the X-Y plane. To move vertically along the Z-axis, the end effector assembly uses a telescopic or articulated arm that can extend or retract. Gantry palletizers are often categorized as Cartesian palletizers due to their linear movement along Cartesian axes. While they perform pick-and-place operations, they are generally slower than Cartesian robots and tend to be larger and more expensive. However, they offer the advantage of lifting heavier loads.
A SCARA robot features an arm that is flexible in the X-Y plane (left, right, forward, and backward) but rigid along the Z-axis (up and down). This "Selective Compliant" characteristic is what defines its name. The "Articulated Robot Arm" of a SCARA resembles a human arm, consisting of two linked segments connected by a joint, allowing for extension and folding. SCARA robots are faster than Cartesian palletizers and can handle multiple palletizing lines, operating at speeds of around 20 items per minute.
This type of palletizer offers two additional degrees of freedom compared to SCARA palletizers. Articulated palletizers feature arms connected by a simple joint at one end, similar to SCARA models, but they lack a mast. Instead, one arm is mounted on a swivel joint with a fixed base, allowing for greater flexibility in movement. Articulated palletizers are faster than SCARAs and can handle multiple production lines, typically processing around 25 items per minute.
Robotic palletizers vary in their approach to pattern formation and use distinct components based on their design. While elements such as check weighers and metal detectors are utilized, they are typically installed as separate pieces of equipment. Below are the common components of a robotic palletizer.
This component supports the end effector and allows linear movement along a single axis. Motion is provided by servo motors through mechanisms such as rollers and rails, rack and pinion gearing systems, or chain and sprocket drives. Beams are commonly found in Cartesian and gantry palletizers.
Mounted on a fixed base, this part supports the beam or arm and end effector assembly. It uses hydraulics, servo motors, or chain drives to enable vertical movement, allowing the connected components to move up and down.
Typically consisting of two linked segments, arms enable the end effector to move horizontally by rotating, extending, or folding.
These components provide rotational movement between various parts of the palletizer system. The number of joints can vary depending on the required versatility of the system.
Often referred to as end-of-arm tools, end effectors are crucial in robotic palletizer assemblies due to their versatility compared to conventional palletizers. They are responsible for picking up and placing products in the correct location and orientation on the stack. Designed to handle a variety of products with a single tool, they can also be equipped to retrieve pallets from a pallet rack or to pick slip sheets, tier sheets, or top caps from a dispensing rack. These features enhance the robot's functionality and efficiency.
Following are the most common types of end effectors.
Clamps lift products by gripping the sides, enabling the handling of multiple items with the same orientation simultaneously, which speeds up throughput. They are particularly useful for stable products or those not suited for vacuum handling, such as HSC (cases with no top) or display cases.
Fork tools are used for delicate, unstable, or special cases like HSC (cases with no top) or warm/hot shrink-wrapped products where gentle handling is necessary. The tool features cutouts that allow it to slide underneath the product for lifting and cradling. A clamp can be added to the fork tool for added stability during movement.
Finger end effectors are mechanical tools that open and close in two directions, providing support underneath the product. They are commonly used for handling bags.
Vacuum end effectors are commonly used for picking up RSC cases and can be configured to handle multiple cases simultaneously. They use a blower to generate a high volume of vacuum necessary to lift thin, porous corrugated boxes made from recycled materials. This approach is often preferred over venturi systems, which rely on plant air that may be unreliable or insufficient for the required air volume.
Bag end-of-arm tools are designed to pick up large bags of product one at a time. They can be equipped to add slip sheets or tier sheets between layers, depending on the speed requirements.
Magnetic end effectors use electromagnets to handle products and are typically employed for stacking and palletizing canned goods.
While conventional palletizers represent the earlier generation of palletizing technology, they are not fully superseded by newer robotic models. Each type of palletizer offers distinct benefits tailored to specific applications. Given the wide variety of industries that utilize palletizers, no single design fits all needs. Below are the advantages of using conventional palletizers compared to robotic ones.
Merits of Using Conventional Palletizers:
Conventional palletizers build the unit load by turning and pushing products into their designated positions and orientations, eliminating the need to pick up and place each item. This method allows for flexibility in handling different packaging dimensions or types without affecting the palletizer's operation. Any necessary adjustments can be made through control program changes, without requiring hardware modifications.
Robotic palletizers can be slow when operating by picking and placing individual products. To improve throughput, they often collect and handle multiple products simultaneously. However, this approach typically offers less flexibility compared to conventional palletizers, which can be easily adjusted to change pattern configurations without impacting throughput.
Benefits of Robotic Palletizers:
For straightforward palletizing tasks where speed is less critical, a robotic arm can be a cost-effective choice. It eliminates the need for additional systems such as conveyors, turning mechanisms, stoppers, and gates. As long as the robotic arm meets the required throughput, it presents a more economical solution.
A single robotic palletizer can be positioned between several packaging lines and handle multiple product types simultaneously. In contrast, conventional palletizers require separate upstream product accumulation systems to manage multiple lines. By eliminating the need for these additional systems, robotic palletizers reduce overall investment costs.
Robotic palletizers offer greater flexibility in changing pattern formations compared to conventional systems. However, it’s important to note that modifying the pattern may impact the palletizer's throughput.
Hybrid palletizers combine the speed and reliability of conventional palletizers with the flexibility of robotic systems. They use traditional row-forming methods, such as turning devices and stoppers, but employ a robotic arm to pick up and place entire layers onto the pallet or stack. This design overcomes the limitation of high-level palletizers, which require products to be moved up by a conveyor, while retaining the advantage of higher throughput.
Another type of hybrid palletizer features robotic pattern forming. In this setup, a robotic arm handles the orientation and positioning of products in the layer-forming area. Once the layer is complete, a conventional palletizer takes over to place it on the stack and manage additional tasks, such as feeding pallets and slip sheets.
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