Palletizers: Robotic vs. Conventional
Versatility, product mix and operational goals are your decision points
Palletizers are great for higher-volume operations. They increase palletizing speed, increase safety, and build solid, consistent pallets without human intervention. In today’s tough labor market, palletizing is one of the best places to automate and reduce manual involvement. Fully-automated systems come in two basic varieties: conventional and robotic, either of which could be the right fit for your operation.
Robotic vs. layer palletizing systems: what you need to know
Above: a brief video breakdown: the critical differences between robotic and layer palletizing systems
Load types and profiles
Both systems can deal with boxes, bales, boxes, trays, crates and other defined loads, but robotic systems handle more types of loads than conventional ones. They are less demanding of rigidity and standardization. Robots, with a variety of end effectors, can handle things like drums that conventional systems struggle to deal with.
SKU variation, condition and quantities
Conventional palletizers lean into a defined process with a defined SKU or load type. If your system is running a single item through the palletizer, conventional tends to be the choice. Robotic systems, however, handle multiple SKUs and load sizes.
Conventional systems process easily defined, rigid, stacked and layered items. If your SKUs are less uniform, robotic systems are the best option. If your operation prioritizes versatility and modularity, choose robotic systems. For consistent speed, though, layer systems are the clear winner.
Speed and throughput factors
Automated systems always palletize more units than any manual equivalent in far less time. They can build bag pallets at up to 4o bags per minute, or 80 cases per minute.
Conventional palletizers are faster than robotic systems. When your process is consistent, with a single pallet of a single load, layer systems are a clear choice. They deliver fast, uniform pallets. Robotic systems are the choice for pallets of mixed SKUs, or SKUs that aren’t as consistent.
Integration with other systems and machinery
Robotic palletizers tend to lend themselves to up-and-downstream integrations better than conventional systems due to their native programmable nature. The chief concern is always the input/output conveyors, warehouse management systems and ERP software. Conventional palletizers may require more customization and integration efforts to achieve similar levels of automation and connectivity. However, both types of palletizers are relatively easy to integrate.
Versatility and flexible operations
Robotic systems handle more types of loads and mixed-unit pallets than conventional palletizers. They palletize multiple products simultaneously, can be outfitted with various effectors and grippers, and handle empty pallets and sheets easily. Conventional systems handle one load at a time, but can handle more of it than a robotic palletizer.
Maintenance, training and costs
Both types of palletizers are relatively low maintenance, but robotic systems require slightly less work than layer palletizers. Robotic palletizers may require more specialized maintenance for robotic arms and controllers, while conventional palletizers may require more routine mechanical maintenance.
Both systems require investment – of time, money and effort, but both offer tremendous ROI if correctly implemented. Conventional palletizer costs are usually driven by speed – the faster it is, the more it costs. Robotic system costs are driven by the versatility and effector/gripper strategy.
The balance between operational flexibility and speed is frequently the decision point when specifying a palletizer. Once your throughput needs, manual labor requirements and load profiles are understood, this decision comes into sharp focus. Robotic systems are more versatile, but cannot match the speed or volume of layer palletizers
Conventional palletizers: speed and consistency
Above: carton and bag style conventional layer-type palletizers
Conventional palletizers cover a lot of ground: they are designed for a variety of loads and a variety of situations. They can be compact, high-speed, low profile, top-layer or any number of other configurations. They can palletize bags, boxes, trays, bales, components and virtually anything else. Conventional systems are a reliable and proven technology, implemented across every industry for decades.
These palletizers work in layers. This means that the load is formed into a single layer, which is then stacked over by the next until the pallet is completed.
How do conventional systems work?
- Conveyors feed conventional palletizers, either at a high or low level.
- Low-level palletizers feed a pallet at a lower elevation, often close to the floor. Low-level systems receive their products at about 3 feet from the floor.
- High-level palletizers build layers from as high as eight feet from the floor. They are typically faster than lower-level systems.
- Typical layer/conventional systems include a pallet dispenser, transfer mechanisms, infeed/takeaway conveyors, case-turning devices, hoists, layer-forming platforms and slip sheet dispensers. They are wired for automation controls.
Automated robotic systems: versatility and SKU variation
Robotic systems use an arm and end effector to lift and manipulate loads from a conveyor or other transport system. These systems can build pallets one SKU at time, or by layer depending on the load, infeed systems and required speeds. Due to their advanced vision systems, they can build a very standardized stack of bags, cartons or other loads. A lot of this functionality depends on their end effectors and tooling.
What comprises a robotic system?
- Conveyors: conveyors deliver units to the palletizer, and often convey finished pallets away. Sometimes, pallets are taken away by forklift or AGV, but they can often be sent downstream to a stretchwrapper or other production step.
- A robotic arm system that removes units from conveyors, then palletizes them. The type of arm depends on the weight of the loads and the speed necessary.
- An end effector. The type depends on the SKU profile; is it a bag? A case? A tray? This is sometimes referred to as end-of-arm tooling, and it can grasp everything from one heavy bag of dog food to an entire layer of heavy cases. Effector types include bundle/clamp grippers, finger grippers, fork grippers, magnetic systems, layer grabbers, pail grippers, ring grippers or pallet/slipsheet grippers. The effector you use is one of the most critical design decision points.
The role of cobot palletizers
Cobot palletizers are a newer entry to the market, and can be an excellent solution for certain applications: typically, slower, lower volume operations with lighter loads and more space constraints.
We cover cobot palletizer options in this post: Automated Palletizing Options: Finding a Happy Medium
It’s all about your needs
Ultimately, the choice between robotic and conventional palletizers depends on factors such as production volume, product variability, space constraints, budget, and long-term operational goals. These are issues that require a full evaluation and careful consideration in advance.
More resources
- Targeted Warehouse Automation: Manual Pallet Handling
- ROI for Warehouse and Manufacturing Automation: A Panel Discussion
- Automation: Starting with a Clean Slate
Tags: Safety & Ergonomics, Palletizers
Scott Stone is Cisco-Eagle's Vice President of Marketing with more than thirty years of experience in material handling, warehousing and industrial operations. His work is published in multiple industry journals an websites on a variety of warehousing topics. He writes about automation, warehousing, safety, manufacturing and other areas of concern for industrial operations and those who operate them.