By 1925, the concept of a unitized load and essentially a modern type forklift enabled improvements in warehouse labor and storage efficiency. Norman Cahners, a US Navy Supply Corps officer, invented and patented the modern 4-way block pallet in the 1940s to improve resupply time for shipping during the Second World War. A pallletized load presents a very low cost per unit for handling and storage, and enables very high cubic efficiency in transport.
Historically, palletizing systems have mostly been implemented on manufacturing production lines; order fulfillment operations have been less able to take advantage of this technology, for several reasons. First, the order flow is often inconsistent - high at peak times, potentially requiring a very high speed machine--and then at slow times trickling off to where a slow machine might be difficult to justify. Second, the cost of warehouse labor has historically been lower than in a packaging or manufacturing facility. Third, loads are often heterogeneous mixed loads, where a machine might struggle. Fourth, distribution centers, especially small ones, often do not have the maintenance personnel required to maintain advanced machinery. Finally, in many applications it is desirable to fluid-load a trailer rather than palletizing.
There are a few factors which are creating change and causing palletizers to become more common in these environments. The increasing cost of labor is obviously a factor. Second, palletizing technology, both robotic and conventional, has become lower cost and more flexible to manage an increasing range of case sizes and pallet patterns, and are even beginning to handle mixed pallets. Palletizers continue to get better and lower-cost to maintain. For receiving operations, say of bulk manufactured goods, there is ample opportunity to implement a palletizer.
Conventional or "layer" palletizers have been around since the 1950s, but the designs have continued to evolve. Layer palletizers tend to be lower cost with a smaller footprint than robotic palletizers. Palletizers can be provided with integrated stretch wrapping further reducing footprint and cost.
Robotic palletizers were introduced in the 1980s. Both types of palletizers have their sub-types within the categories. There are numerous options, models, and accessories to consider in selecting a palletizer.
For a robotic palletizer, although the robotic arm may be very reliable (typically 50,000 MTBF for a tier one robot) the overall system is only as good as its weakest link, which is typically the conveyor, special positioning devices and the end-of-arm tool. Robotic systems need to be integrated from pieces purchased from different suppliers. What needs do you have around corner boards, slip sheets, tier sheets, stretch wrapping? Look at empty pallet dispensers and infeeds and full pallet staging and takeaway. Consider your ability to maintain in-house, or support contracts, especially for a robotic palletizer.
Perhaps more than other material handling systems, palletizing requires careful study of all the parameters. System performance and cost is heavily dependent upon small details and complete specification of the expected product range, pallet design and quality, install area, etc. For example a simple question like "cases per minute?" is a huge "It depends!" So especially in shopping for a palletizing system, be patient and take the time work through all of the details. Like many tools, the ability to handle most of what you need it to do may cost a fraction of the ability to do absolutely 100% of what you need. Consider the delivery system and application of your palletizer. Evaluate your supplier based on not only the palletizer technology but how they can translate your operational needs into an overall system that includes infeed, takeaway, maintenance accessibility and other requirements.