The first step in choosing your palletizing equipment is analyzing the full range of products and packaging types running on your line. Take some time to determine how each item should be handled. For example, can the packaging support its own weight during transfer? Or, will it need to be supported from underneath? How stable is the pallet load?
Here are some important factors to consider:
- Size, shape, and weight of product
- Stability and construction of load
- Secondary packaging
- Pattern-forming capabilities.
Robotic arm palletizers are a legitimate solution for high-SKU, lower-speed operations as well as applications where the product shape demands the precision of a robotic arm, such as bags and pails. Robots pick and place the product, while conventional palletizers convey the product into position. For items such as pails and bags, the ability of a robotic arm to precisely place the product is very important. Pails must “nest” together on the lid of the pail below when stacked on a pallet, and bags must be gently placed straight and square without disturbing contents. Additionally, robots have the ability to work in confined spaces and dusty environments, adding to their appeal for the bag palletizing applications.
Because they never have to pick up the product, conventional palletizers are more tolerant of packaging changes. Cases, trays, film bundles, poly sacks, etc., can all be handled on the same conventional palletizer. Additionally, conventional palletizers can also be more flexible than robots in regards to product packaging and stacking patterns, handling each case individually so that pattern changes have a relatively small impact on rate.
Evaluate the rates required on your packaging line
The throughput capabilities of your material handling system can vary greatly depending on which tool you use and the product you are palletizing. A good starting point is to determine an acceptable range of line speeds (cases per minute), which can help you better evaluate your equipment options.
Robots are intermittent motion machines, and it would take many of them working together to achieve these speeds. Conventional automatic palletizers are capable of very high speeds, upwards of 200 cases per minute; and inline, continuous-motion palletizers are capable of handling 20 layers per minute. For high-speed manufacturing operations, there is simply no other alternative that can get the job done.
So, robots can handle difficult-to-handle loads, but conventional palletizers can handle higher speeds. Conventional machines can make pattern forming a breeze, but robots can create more retail-friendly loads. What if you need both? The good news is that you might not have to choose. New “hybrid” machines that integrate robotic arms for pattern forming with a conventional palletizer for layer forming bring together “the best of both worlds.” This concept seems to combine the best of both technologies for higher-rate applications. Robots are used to precisely turn and position the cases, while conventional technology is used to square and deposit the layers.
The chart below is a quick reference highlighting the ideal applications for robotic vs. conventional palletizing technologies:
Evaluate staff and maintenance
Now that you have evaluated your product mix and your throughput requirements, you must also consider your staffing and maintenance capacity. Robotic palletizers and conventional machines are quite different in terms of their maintenance needs and staff requirements.
Some considerations for your staff and maintenance include:
- The learning curve for robotic applications vs. conventional applications
- The operation platform—PC, PLC, etc.
- Inventory of parts
- Floor space considerations.
The conventional palletizer is the clear choice for all of the above considerations. For many on your staff, the conventional palletizer is just another piece of machinery operating on the same control platform as hundreds of other pieces of equipment in the facility.
Robotics, on the other hand, have been intimidating creatures on the facility floor. Some maintenance crews may hesitate when asked to perform routine or emergency maintenance on a robotic arm, especially in regards to their control platform.
However, with the recent innovation of the PLC-controlled robotic arm, this automaton becomes less of a "black box" or foreign concept and is suddenly a more familiar piece of machinery. This PLC-based control system enables your staff to deploy new robotic palletizing solutions while maintaining your standard control platform, streamlining complex control communication, reducing critical response time, and minimizing changeover delays.
Clark is director of international operations for Intelligrated.