The Intricate Dance of Palletizing and Depalletizing: Behind the Curtains

If you’ve ever watched a beautifully choreographed dance, you might be captivated by the synchronization, precision, and fluidity of the movements. Similarly, in industrial automation, a dance unfolds daily, albeit with less of the human touch and more of the mechanical flair. Enter the realm of palletizing and depalletizing systems.

The Palletizing Ballet’s Lead Dancers

Robotic Palletizers are akin to the prima ballerinas of our industrial ballet. Brands like FANUC, KUKA, and ABB dominate the stage with precise and swift movements.

Each of these robots is equipped with an EoAT, or End of Arm Tool, which allows them to manipulate products coming in from the infeed conveyor.  These tools are designed specifically for the task they will be performing. For example, in the beverage industry, the tool could consist of two sheets comprising a sturdy yet texturized material to manipulate different-sized boxes. These tools are generally fitted with anodized parts and stainless steel to prevent rust build-up. After all, no machine is perfect, and while they are built and programmed to prevent crushing bottles, it does happen. This tool turns and pushes boxes in the correct orientation and side for the palletizer to square up and finally drop onto the pallet.

For picking and placing, claws, suction cups, and magnets are used depending on the material. Likewise, these tools are also helpful when depalletizing products, as they can reverse their operation to place products on an infeed conveyor system. These robot systems generally are smaller and less complicated than a larger beverage sorting machine.

The Ensemble of Sensors and Vision Systems

In a grand dance performance, an observant director guides the artists, ensuring every move is timed right. In the ballet of palletizing systems, photosensors play this pivotal role. These are the “watchful eyes,” ensuring every sequence flows without a hiccup. They are used extensively throughout the system and conveyors, all linked together and communicating through their software. How exactly do they work?

Detection: Just as a director catches every nuance in a dancer’s performance, photosensors detect the presence or absence of objects. Using a light source (usually infrared), they emit light beams. When an object breaks this beam or reflects light back, the sensor knows something is there.

Communication: After detection, the photosensor sends a signal like a director giving a cue. In a palletizing system, this might mean telling the robot it’s time to pick up a product, move to the next position, or stop if something’s amiss.

Seamless Integration: The dance floor of our palletizing system is busy, with conveyors moving products and robots swinging into action. Photosensors help keep this dance harmonized. They can be strategically placed to monitor product flow, ensure items are correctly queued and spaced on conveyor belts, or check if a pallet is in place and ready for the next layer.

Adaptability: Modern photosensors can be adjusted or programmed to detect different light levels. This allows them to work with a range of products, whether they’re shiny, dark, transparent, or opaque. Just as a dance director would adjust to the styles and strengths of various performers, our sensors adapt to the unique characteristics of different products.

The Conveyor Rollers

Think of conveyor rollers as the stage assistants, always ensuring that props (products, in this case) are ready for the performers. They create a continuous stream of products, aligning and queuing them up so the robotic palletizers never miss a beat. Behind the conveyors are the workers picking products and feeding them. The logistics software will use the conveyor to shift products and queue them as needed. This is important so the palletizer does not grab one product, think it’s another, and crush it. The strategic placement and synchronized speed of the conveyors and logistic systems ensure no overcrowding or chaos on the dance floor.

The Art of Stacking

Products aren’t merely dumped onto a pallet; they’re arranged in a planned, structured manner. Whether it’s the traditional column stacking, where products are stacked in straight columns, or the interlocking style, where products are alternated to nestle into each other, every move is calculated. Some sophisticated systems even use brick stacking, creating a weave-like pattern, ensuring stability and optimal use of space. These stacking methods reduce damaged products during shipping and are generally easier to shrink-wrap before shipping. Moving arms help compress the product layer and ensure it is square before dropping it down onto the pallet. Some palletizers use a curtain of slick plastic rollers to drop product onto the top layer gently, only to lower that pallet down to raise back up for the next layer of product to be compressed and dropped. This is where the photo eyes come into play as they can see how much product is already stacked, how much the pallet needs to be lowered, and when to stop it so it doesn’t run up into the top apron.

The Maestro: PLCs

Behind every grand performance is a maestro, guiding and overseeing every move. In our ballet, PLCs like Siemens, Allen-Bradley, or Mitsubishi play this role. They coordinate the dance, receiving inputs from sensors, interpreting the data, and sending commands to the robots and conveyors. These controllers are the brainpower, ensuring the dance remains harmonious and without missteps. These controllers are often contained in the systems, sometimes even air-conditioned cabinets. As expected, they are also pre-programmed so that factory workers should never touch them.

Depalletizing Machines

Depalletizing is a critical process in the world of manufacturing and distribution, responsible for efficiently unloading items from a pallet and getting them ready for the next steps in the production or shipping process. These systems complement the outbound palletizers to create a large, automated ecosystem within the facility.

How Depalletizing Machines Operate:

Recognition and Vision Systems: Advanced depalletizing machines incorporate vision systems or sensors that allow the machine to accurately determine the loaded pallet’s structure, size, and pattern. This is essential to plan the unstacking sequence and prevent potential mishaps.

End-of-arm Tooling: These machines employ a variety of specialized tooling at the end of their robotic arms to adapt to different types of products. Common tools include suction cups for smooth surfaces, mechanical grippers for items that require a firmer hold, and magnetic tooling for metal products.

Layer-by-layer Operation: With their recognized pattern, depalletizing robots work sequentially. They remove items layer by layer, ensuring the products are handled carefully, avoiding damage or misalignment.

Integration with Conveyor Systems: Once the products are picked from the pallet, they are transferred to a conveyor system. This facilitates the next steps in their processing, whether it’s further production stages, sorting, or packaging. Efficient synchronization with conveyors ensures that items are smoothly transitioned without backups or jams.

Feedback Loops and Adaptability: Modern depalletizing machines are equipped with feedback systems. They can adjust their operations in real time if they detect anomalies or unexpected conditions, such as a misaligned product or an unforeseen obstacle. This ability to adapt thanks to sophisticated programming and integrating multiple sensors and photo eyes. It never hurts to have human intervention if something were to go awry. After all, sometimes a human’s judgment is better than the machines, so long as they take the proper safety measures to work alongside the system.

Human Operators

Last, human operators are the choreographers, fine-tuning the machinery, intervening when necessary, and ensuring the ballet goes off without a hitch. They program the systems, choose the stacking patterns, and monitor the performance, stepping in gracefully when needed. They are also there for damage control, helping clean any male performances of the machines and helping to hand stack any pallets that may be undone. Forklift drivers are also the unsung heroes of these systems, as they’re constantly driving the products to and from delivery trucks. Pickers also ensure that the correct products are fed into the system, and system monitors watch to double-check that the queue is correct.

PLC technicians and palletizer specialists are also crucial for every system installation. Since every environment is different, they must ensure the system runs smoothly. They also help train the workers at the factory to use the machine. Going over the safety factors of the palletizing system is especially important, as any negligence can lead to significant injury.

Factors to Consider

While a sight to behold, the ballet of palletizing and depalletizing is not merely about donning a pair of ballet shoes and twirling around. There’s intricate planning behind the scenes. Before one leaps into the world of robotic palletizing, it’s essential to consider the choreography’s many facets:

Labor Factors: Assess both the availability and costs of labor. Automated solutions may provide advantages in areas with labor shortages or high wage expectations. While the initial cost of installing the palletizing system could be eye-watering, the return on investment is often worth it. Some companies even install these systems with extra unused lanes to account for any growth in the future. After all, rearranging or reinstalling an existing setup to accommodate a new machine is often much more expensive than installing the extra lanes and only using them once needed.

Product Specifications: Evaluate the size, shape, weight, and packaging of your products. This will influence the type of robotic system and tools needed.

Infeed and Outfeed Lines: Determine the number of infeed and outfeed lines your operations require, such as 1 in / one out, 2 in / 2 out, or custom configurations. Deciding what queuing system and if there are any other additional add-ons would be a good idea in this step. Also, accounting for hand stacking and cleaning up at the end of the line is good foresight.

Facility Layout: Review your facility’s layout and available footprint to ensure there’s enough space for the robotic system and its associated equipment. Room for inventory, shipping, and receiving is a given but may shrink significantly depending on the system used.

Robot Capabilities: Focus on robotic reach, payload, and speed. The specs of your chosen robot must align with your operation’s demands. The software of the robot is also something to be taken into consideration. The producer of the palletizers generally overwrites them and is a part of their “ecosystem.”

Axes of Rotation: Decide on the necessary item manipulation, determining whether you need a standard 4-axis robot or more intricate 5- or 6-axis robots for tilting or rotating items. Generally, depalletizing systems require more axes of motion.

Throughput Rates: Estimate your expected throughput rates to determine the number of robots required for optimal efficiency. As mentioned before, it is also a good idea to look at the companies’ statistics and see their projected growth to determine the throughput rates from 5 to 10 years down the line.

Stacking Patterns: Understand the potential pallet stacking patterns. The complexity and variety of these patterns can affect robot programming and operation. Using standard, half, and other specialty pallets will increase the complexity of the machine, especially in the beverage industry. Automatic pallet dispensing options could also be added to the system to make it flow even easier than it already is, especially if multiple pallets are used.

The Final Curtain Call

This ballet of technology and engineering is a testament to the advances in industrial automation. A fusion of art and science, this dance ensures that when you hold a product, you’re holding a piece of artistry crafted through precision and grace. Machines like these prove just how effective automation could be if implemented correctly. The mix and match of components, actuators, switches, and photo eyes, composed by a group of technicians, created this system to increase output efficiency vastly and with less collateral damage to products. While this technology is still relatively new, it is exciting to consider what could be next to complement this intriguing performance.

This entry was posted on December 10th, 2023 and is filed under Automation, Education, Technology. Both comments and pings are currently closed.