Finding the Best Solutions for Palletizing & Depalletizing
Knowing your options and selection considerations will help you to make the right decision for long-term productivity gains.
The decision to upgrade your packaging line can benefit your operation in many ways: increased production, reduced labor and insurance costs, less liability, improved product handling and protection during transport. Or maybe you are looking to solve an operating issue that has been plaguing your line. In any case, the decisions you make during the upgrade can affect your productivity for years to come. Understanding your options, and what you need to consider during your selection, will help you to make the right decision that will bring long-term gains to your productivity.
Palletizer Selection Considerations
Robotic, conventional, hybrid? Automatic or semi-auto? High or low level? The right machine for your line will depend on many factors. Not long ago, there were major differences in cost and capabilities between conventional and robotic palletizers. Robots were best for multi-SKU applications that ran at relatively low speeds, while conventional palletizers were applicable for dedicated medium and high-speed lines. Today’s robotic palletizers can achieve higher speeds, and new control technology has given conventional units greatly increased flexibility with no downtime for changeover. Added to the mix is a new breed of hybrid palletizers that combine robotic product placement with conventional squaring devices. Finally, semi-automatic palletizers that offer a cost effective upgrade from manual palletizing for low speed lines. So, what is best for your application? First, you need to analyze your requirements:
- Packed in a case, tray, display tray, tote or shrink-wrapped bulk packaging?
- Are shippers solidly packed, or is there headspace that can affect stacking strength?
- Is it fragile or of high value?
- Is it very heavy or lightweight?
- If bags, are they paper or poly? Are the contents settled or will bags need to be flattened for palletizing?
- How many SKUs do you palletize?
- Where will the palletizer be located in your plant?
- Will you feed multiple lines to the palletizer?
- How are products conveyed to the palletizer?
- How much floor space is available?
- What are your current pallet patterns? How often will this change?
- Do you make display pallets? End-of-aisle displays? Label out loads?
- Do you make dedicated or mixed load pallets, or both?
- Do you require tier sheets, glue dots or full pallet shrink-wrap?
Speed Requirement: As the final piece on the packaging line, your line efficiency will be directly related to your palletizer’s speed and production. Mismatched speed capability and/or downtime at the palletizer can cause backups on the entire line. Make sure you are talking the same language as your supplier when discussing speed. Conventional high-level palletizers are generally rated at cases/minute, while low-level units are rated at layers/minute and robotic palletizers spec at cycles per hour.
Budget: No small consideration, your budget can help to define your selection. If your budget is tight, look for palletizers with modular designs, which allow you to add future upgrades as your budget allows.
Once you have all of your specifications and production goals in place, it’s time to talk to suppliers. Here are some basic guidelines that are applicable to palletizer selection today — keeping in mind that with advancing technology on all fronts, these guidelines may not be applicable for every situation. That is why it is important to have all of your specifications for potential suppliers, so they can evaluate your operation and help you choose the best technology for your line.
Speed: Conventional high-level palletizers are still king for high-speed lines. Conventional low-level and robotic palletizers excel on mid-range lines, and semi-auto palletizers are a solid choice as an upgrade from manual labor. When determining your required speed, it is best not to inflate your speed requirement as this can increase your machinery expenditure for speed capability you do not need. More importantly, make sure the machine you are buying has a good track record of performance and buy the speed capability you actually need.
Budget: High-level conventional palletizers have typically been more costly than low level, due to the cost of the catwalks, stairways and accessory equipment. Both high- and low-level machines typically can be programmed for new products at the operator station. Robotic palletizers usually are in line with high-level palletizers. However, their price will depend on the complexity of the application and programming required, with a simple, one-axis robot at a lower price point. Semi-automatic, low-level machines are typically one-third the cost of high-level palletizers.
Maintenance: Conventional palletizers require regular maintenance; however, the maintenance can be performed by a qualified plant mechanic. Low-level palletizers can be serviced at floor level, where high-level machines that operate at ceiling height can be more challenging to service or repair. Robotic palletizers have fewer mechanical components and extended duty cycles, but need regular lubrication and maintenance of end of arm tools (EOATs), which typically is best performed by a specially trained mechanic. However, as robots continue to enter the palletizing space, this specialty work will become mainstream.
Flexibility: All palletizing styles offer a great deal of flexibility, and most offer pallet configuration programming at the control panel. Robotic and hybrid palletizers can be fitted with a great variety of EOATs to handle a wide variety of sizes and shapes and can assemble mixed load pallets and “rainbow” loads with different products on each layer for specialized shipments to retailers and club stores.
Floor Space: This is an important concern, with floor space at a premium in many plants. Conventional high-level palletizers typically occupy the most floor space due to their construction and related catwalks and conveyors, conventional low-level palletizers require about 30% less floor space. Robotic palletizers can fit in smaller spaces, depending on the configuration and conveyor requirements. If floor space is an issue in your plant, this should be covered in your initial discussions with suppliers to determine whether a small footprint conventional palletizer or robotic palletizer will best suit your line layout.
Bulk Container Depalletizer Selection Considerations
Your depalletizing solution can literally make or break your production line, as consistent and reliable empty container feed is essential to packaging your product and meeting your production goals. Whether you are transitioning to bulk from reshipper cases or planning a new line, careful consideration of these key points will help you to avoid problems and reach your productivity goals.
Container Specifications: Bulk depalletizers run a wide range of container types including glass, plastic, steel and aluminum cans, and composite containers, in standard and many non-standard shapes and sizes. Once unloaded from the pallet, the discharge and line feed configuration will be determined by your actual container size and orientation requirements, so it is important to discuss this with your potential suppliers and provide samples for evaluation. You can rely on their expertise to help you determine the best line feeding solution: whether a simple single filer or laning device, to a row stripper that maintains container orientation, or possibly a bottle unscrambler to orient and single file small or lightweight plastic containers.
Line Speed: The industry-accepted standard is to spec your depalletizer volume at 20% higher than your filler volume. In evaluating depalletizers, it is important to look at layers/hour, not layers/minute, because different manufacturers rate their equipment by sweeps/minute and may not include cycle time between pallets. For companies that run slow speeds, a manual depalletizer may be the first step to automating this operation.
Plant Layout: Your decision between a low-level and high-level depalletizer will likely depend on your line layout. If you are planning to depalletize at the receiving dock and transport containers overhead to the production line, a high-level depalletizer is a solid choice. However, low-level depalletizers can also discharge containers at ceiling height so this is best discussed with potential suppliers. If your depalletizer will be positioned before the bottle cleaner, a low-level machine with line elevation discharge will save you the expense of overhead conveyor and lowerator that would be required with a high-level machine.
Budget: The purchase price and installation costs are typically higher for high-level depalletizers, due to the platforms, catwalks and lowerator required to transport containers back to line elevation. Low-level depalletizers require less time for installation fitting to existing line conveyors.
Additional Considerations: Many companies plan machinery upgrades to reduce costs. This makes perfect sense, as reducing production costs through automation can generate increased profits. Considering that the cost of automating your depalletizing and/or palletizing operations can easily reach hundreds of thousands of dollars, it can be appealing to look for the least cost solution to realize a quick payback. However, some would consider this a shortsighted approach, as the typical packaging machine has a projected operating life of 20 years. It is important to evaluate more than the original purchase price. Also factor the costs of installation, operation, training, maintenance, change-
over, upgrades/spare parts and even utilities, as all of these costs will impact your ultimate return on investment.
A-B-C Packaging Machine Corporation manufacturers depalletizers, decasers, case erectors, sealers, packers, palletizers and accessory equipment for a wide range of applications. Contact A-B-C, located in Tarpon Springs, FL, at abcpackaging.com.