Automation: Packaging

March 20, 2020

by Stephen Gibson, PE, CSCP, PMP

Automation is an exciting, and sometimes scary, topic for many businesses. Most businesses love the thought of dumping raw materials into one end of a machine and a finished product coming out the other. The reality is that machines capable of accomplishing this feat are often cost-prohibitive and unforgiving when it comes to changing demands. Businesses will sometimes invest in such equipment only to see demand drop. Suddenly, the piece of equipment forecasted to have a two-year payback is now sitting idle as it was sized too large. The opposite can happen as well. Demand skyrockets and the shiny new robot that was just sitting useless now cannot keep up with demand. And, there is no room for additional equipment. Then there is the question, "what happens when products change?" That custom machine you had made no longer works for the new design, and yet again your new robot sits without any use. These are all challenges and dilemmas companies face when trying to make an educated decision on what to automate, how much to automate, and when to automate. To answer such business questions takes more than just a financial advisor.  Businesses need professionals who understand processes, equipment, and financial implications. This is another area of expertise for Industrial Systems Engineers.

The Pet Food Predicament

Our Industrial Systems Engineer has experience automating everything from simple welding cells and paint booths to warehouses. One of the projects was to automate three packaging lines for a pet food facility. The facility was packaging bags ranging in weight from 5 pounds to 50 pounds. Being a private label manufacturer, there was also speculation that weights could increase up to 100 pounds. There was also limited floor space, demand rates of 20 bags per minute per line, customer-requested quality improvements to the bundling of small bags, and financial requirements of 2-year simple payback or better. 

To meet the demands of this project, two different automated packaging lines were designed: one to manage large bags ranging from 25 to 100 pounds and a second for bags weighing less than 25 pounds complete with bundling capabilities. Starting at the front of the line, the food industry in the US is required to have a minimum amount of product in all packaged goods per the label. If a bag says 25 pounds, every bag will have at least 25 pounds or more. This requirement forces companies to “give away” some level of product. As a benefit to the new packaging line, new automatic scales were integrated to reduce the amount of product “give away” in addition to being able to work with automatic bagging equipment. Automatic baggers were designed into each line eliminating the need for an operator to hold bags while being filled. These were outfitted with both gluing and sewing capabilities to meet varying customer requirements for sealing. This not only reduced labor costs but eliminated human interaction with the product reducing spills. The result was a lower cost of operation along with a safer and cleaner process. After the sealing process, the two lines became much different.

Large Bag Lines

On the large bag lines, the bags were then flattened to aid in the palletization process. This conveyor system was also designed to act as an accumulation system as needed feeding into the robotic work cell. Here a pallet would be dispensed onto a conveyor with a slip-sheet placed on top of the pallet. This provided a means for both forklifts and slip-sheet warehouses to handle the product. The bags were then stacked on the pallets at rates averaging 20 bags plus per minute (1 ton every 2 minutes). Pallets then traveled to a stretch wrapper outfitted with a top sheet to fully enclose and protect the load.

Small Bag Lines

The small bag line presented another challenge. Again, footprint and cost issues presented obstacles to automating this line in regard to bundling. In the manual set-up, operators would gather the bags into a large plastic bag and heat seal the plastic bag. Warehouse retailers such as Costco and Sam’s sell small bags of pet food in bundles. This cuts down on handling. Heat sealing automatically could be done with traditional heat bundling equipment, but this leaves openings on each end of the package referred to as “bullet holes”. Customers will try to lift the bundles using these holes breaking the bundle and making it difficult to sell. A single company held a patent to resolve this issue completely enclosing heat shrink bundled items. Their one piece of equipment was selling for approximately $500,000 and was a large footprint. In addition, their solution required two layers of film which would have significantly increased packaging costs. The solution was a new piece of equipment that was developed in conjunction with a packaging equipment manufacturer. Instead of two pieces of film, a slightly wider sheet of film was utilized with end seal bars. This resulted in a footprint of approximately 40% smaller and 30% less packaging cost. Also, the equipment cost only $150,000 saving 70% on the capital investment. From this machine, the bundles followed a similar process to the large bag lines feeding in a robotic cell for palletizing and to an automatic stretch wrapper.

Automated Savings

By utilizing new technology and being willing to develop new equipment, the company was able to fully automate all three lines without adding square footage or sacrificing floorspace from another area of the facility. Once complete, the entire project was completed for $1.5M and had annual labor savings of $500k. In addition, the company realized savings in packaging and product give away as well as improved safety and ergonomic conditions for the employees.