Phoenix Case Study: Light Weighting
Working to Make Caps Lighter and Using Less Plastic
Plastic packaging is affordable, adaptable, and cost effective. It has become a staple in the packaging industry over the last 50 years. Plastic waste, however, is problematic. Not all plastic is easily recycled, and it breaks down so slowly that it remains in the environment for a long time. As a manufacturer of plastic closures, PHOENIX takes seriously both our commitment to our customers and their needs, as well as our impact on the environment. While a closure is a small component of an overall package, it is essential to how a package functions. At PHOENIX, we do our part and take responsibility for addressing the problem of plastic waste by reducing the amount of plastic resin that has the potential to be introduced to the waste stream. When caps are lighter, they use less resin. By reducing the amount of plastic used in the closures we make, less plastic has the opportunity to enter a landfill or end up in lakes, rivers, and oceans. Because PHOENIX manufactures billions of closures each year, even a small reduction in cap weight can make a substantial, positive impact on the environment.
What is Light Weighting?
Removing material such as resin and colorant from the closure without compromising the integrity of the part is often referred to as “light weighting”. The reduction in resin needs to be done in a way that has minimal consequence on the overall performance and quality of the cap. Using simulation technology, PHOENIX can evaluate the lighter-weight design to ensure that the cap still functions well, resists breakage when dropped, and is still aesthetically pleasing and able to enhance the brand of the end product.
The Benefits of Light Weighting for the Waste Stream and Beyond
Recently, PHOENIX implemented a light-weighted redesign of their 53 closure. The project resulted in a 0.6g reduction in weight per cap. That may not sound like very much, but it equates to a 73,000-pound reduction in the amount of resin used per year in just this particular closure. That’s enough resin to fill 15,597 gallon jugs(1)! Using that much less resin from the point of its manufacture all the way through the end-of-life of our caps could also save up to 219,000 lbs of carbon dioxide from being emitted into the atmosphere.(2) It would take 122 acres of U.S. forests an entire year to sequester that much carbon! (3)
Clearly the benefits of light weighting go far beyond relieving the waste stream. In addition to having a reduced carbon footprint, lightweight caps can also be produced faster through a shortened molding cycle which, in turn, requires less energy consumption. When caps are redesigned for lighter weight, the entire manufacturing process is adjusted. This can give PHOENIX opportunities to create larger molds with higher cavitation, further reducing the time and energy needed to create the closures.
A light weighting project also provides our PHOENIX engineers the opportunity to ask more questions about optimizing the closure. What other aspects of the cap design can be improved? For example, PHOENIX completed a lightweight redesign on our largest 120mm closure which allowed the newly designed cap to be stacked differently after production. This optimized the space in the packing carton and allowed more closures per box, increasing carton capacity by 89%. PHOENIX sees this as a triple win because not only do we reduce the amount of plastic being used, but we also achieve a sizeable reduction in the use of corrugated shipping cartons and in the cost and creation of greenhouse gas emissions from the transportation of the product to our customers.
These important design changes also have a positive impact on the bottom line. With improved efficiency, there are also lower costs. The brand owner sees the savings and improved overall sustainability for their product, while consumers benefit from continuing to get the performance and quality they desire without any compromise to functionality.
What is Involved in the Lightweight Redesign of a Closure?
Using simulation technology PHOENIX can evaluate the lighter weight design to ensure that the cap still functions well, resists breakage when dropped, and is still aesthetically pleasing and able to enhance the brand of the product. After reviewing the initial simulated design, PHOENIX produces prototype caps for physical testing and evaluation to confirm form and function. Additional tweaks are made to the design as needed for optimization. Lead customers are then provided samples to run on their manufacturing or filling lines to further evaluate and approve prior to commercialization.
Some adjustments are usually needed to the tracking and infeed systems to function with the likely smaller outer dimensions of the new, lighter cap. The structural strength or rigidity of the new cap may be somewhat different, which can be accommodated by making slight adjustments to handling equipment. The testing process is highly collaborative and offers many opportunities for our internal teams to collect and apply feedback from interested customers. Before the redesigned cap is launched to market, final approval is needed from our quality and engineering departments, as well as the customer.
How Does PHOENIX Determine Which Caps to Redesign?
PHOENIX’s aim is to create a simple yet effective design in all our closures. Throughout the next several years our 130-year-old company will continue to innovate and redesign closures to be lighter weight and use less resin. “There really isn’t a good cap or a bad cap to consider redesigning. Any and all closures are considered,” Tom Stoneberg, PHOENIX, Senior Designer. Tom notes that oftentimes the process can be relatively straightforward, as caps designed decades ago usually have been overbuilt with excessive thickness and too much material. Designing for optimal function and efficient manufacturing requires an iterative approach that involves multiple designs to be considered and evaluated via structural (FEA) and process simulation (Mold Flow) before prototypes are produced and then evaluated for confirmation.
But What about the End User? Are They Going to Notice a Difference in the Lighter Weight Cap?
“Through a combination of CAD simulations, physical testing, and our past experience, we are able to selectively target areas where we can reduce the amount of material while still maintaining our high standards for performance and durability,” stated Rick Palandri, PHOENIX Design Engineer. “This addresses the most common concerns of ensuring sufficient structural integrity and whether the new cap will stay round, not ovalize, and perform on the capping equipment as well as the previous heavier design.”
Overall, the expected and typical outcome is that the retail customer who opens and closes a product every day is not going to notice a difference in the performance of the closure. The sustained positive impact on the environment gives light weighting closures a check in the ‘win’ column for manufacturers and customers alike.
1 Assuming a pellet density of 35 pounds per cubic feet
2 Sources: https://archive.epa.gov/epawaste/conserve/tools/warm/pdfs/Plastics.pdf
Alsabri, A.; Tahir, F.; Al-Ghamdi, S.G. Life-Cycle Assessment of Polypropylene Production in the Gulf Cooperation Council (GCC) Region. Polymers 2021, 13, 3793. https://doi.org/10.3390/polym13213793