Palletising: a choice dilemma
January 1st 2008

Jerry Woodhouse, European MD, FKI Logistex, looks at palletising trends and examines the decision-making process when choosing between conventional and robotic technologies

In today's competitive manufacturing environment, the demand for improved line efficiencies and reduced costs means manufacturers are increasingly looking to automate their material handling systems, and the palletising and depalletising function is no exception to this trend. Even if moving as few as 5 cases/min, there are benefits to be gained from transitioning to an automated solution. Then, as speeds increase or the product becomes difficult to handle, automating usually becomes vital.

Designed to remove empty containers, feed them back into a filling line and stack finished product, automated palletising and depalletising has long been a standard of manufacturing sectors such as beverage, food and consumer goods, and offers a number of benefits. These include improved operating efficiencies, labour savings, reduced costs, increased safety levels and significantly higher throughputs.

Ultimately, carefully constructed Return On Investment projections should be the major consideration in deciding whether to choose an automated solution, and if so, whether to use a conventional palletising machine that forms rows and layers, or a system based on robotic pick-and-place technology.

Until recently, the most widely accepted method for an automated solution was based on use of purpose-built, conventional palletising or depalletising machines, but over the last few years robotics have increasingly developed as a viable alternative. For example, a solution for a 100-case/min palletising operation that once could only be accomplished using a standard, high-speed case palletiser may now be accomplished with multiple robotic arms working in unison at a comparable cost. When it comes to pattern flexibility, robotic and conventional palletising solutions can be configured for virtually any pattern.

The key, therefore, is for manufacturing operations and supply chain managers to carefully consider their options and determine which solution is the best fit to meet other parameters in an application.

Though not a rigid rule, conventional palletisers are more commonly used for applications requiring higher speeds or involving products with reduced packaging. Robotic solutions generally fit lower-speed lines and situations where the palletiser needs to handle multiple lines simultaneously. Because of their smaller footprint, robotic solutions are an option where floor space is at a premium.

It is advisable not to be swayed by the claim from robotics companies that robot solutions are more flexible than conventional. Depending upon the application, conventional solutions may be the more flexible alternative. Do a thorough technical evaluation before making a final decision If robotics appears to be the answer, an additional part of the decision-making process will be what types of robots and components will provide the best overall solution. Most robotic palletising applications have either gantry robots, known as 'square' robots, or jointed-arm robots, known as 'round' robots, both named after their types of motion.

Gantry robots are linear-motion, meaning they move up, down and across in a work envelope that can be more than 25m long. They are typically built to the dimensions of a specific project and offer more overall flexibility, including the capacity to work with a large number of pick-and-place locations.

Jointed-arm robots are more limited in the size of their work envelope but are generally more economical and faster. In a typical palletising application, a jointedarm robot is capable of building up to four pallet loads within its work cell.

Another important decision in a robotics application is which end-of-arm tool, or 'end-effector;' will be used. While vacuumtype end-effectors have many uses in general manufacturing, they may not be the most appropriate for palletising applications, particularly for items packaged for product display. In these situations, a side-clamp or fork-and-clamp tool is a better choice, due to its flexibility.

Choosing the right partner to build the solution is key. Since core knowledge of palletising or depalletising engineering is required to adequately specify this kind of solution, it is essential to select a business partner who has experience with these types of operations.

Palletising and depalletising projects, particularly in manufacturing, require proven material handling integration experience in order to determine whether a dedicated robotics solution is appropriate, or whether a mix of robotics and other technologies is required. Find an integrator that specialises in the task you are trying to accomplish. Experience in robotic welding systems will not guarantee success in robotic case palletising. A visit to a customer site can provide a wealth of information. It is prudent to obtain a firm guarantee on robotic rates, including consequences if those rates are not met.

A trusted partner who can identify and recommend a palletising solution to your complex production requirement is an invaluable resource, especially one able to integrate the system into a company's wider material handling system and controls. Deciding whether to use conventional or robotics technology for an automated palletising or depalletising solution can blur your vision. A company such as FKI Logistex can bring it back into focus.

More articles from FKI Logistex: