When some people think of engineering, they immediately think of bridges, airplanes, or computers. However, engineering is involved in almost everything we use in our daily lives. For example, almost everything we purchase or store comes in some type of box. The truth is, many of these boxes are engineered to be folded together using as little material as possible while providing the most strength as possible. Indeed, much time and thought can be spent designing a single box for an application. Likewise, plastic bottles are another product many people may take for granted. Nevertheless, just like boxes, much time and research is spent to create the most optimal product possible.
Queen's University in Northern Ireland has spent more than 20 years researching and experimenting with plastic bottle moldings. The Mechanical and Aerospace Engineering School is the foundation for the Advanced Materials and Processing group. This group has become the experts of the world on forming and creating new bottles. In fact, due to the pressure of big companies to go green, creating a plastic bottle made from fewer materials, while still keeping its durability, is an extremely sought out service. Therefore, the school's materials group is now receiving lots of attention for their work and big name companies are seeking their skills.
The biaxial stretcher, used for material characterization, was developed in-house by Queen’s engineers to provide validated data for their simulations.
(Source: Dr. Gary Menary/Queen’s University Belfast)
“The challenge our industrial partners face is to make a bottle with as little material as possible, yet still have the proper end-service performance requirements,” Dr. Gary Menary, senior lecturer, School of Mechanical and Aerospace Engineering, told Design News, in an email. “It's a very competitive field. A typical large-scale converter makes about two billion bottles annually. So one gram taken out of a bottle for them translates into two million kilos of material, equating to $3M saved per year.”
The school's journey to the bottle molding process began in 1991 when it received funding from the UK Research council. The goal was to eliminate any trial and error associated with injection stretch blow molding (ISBM). Through years of research and advances in ISBM, Menary became a team leader in 2003. In addition, they have also been involved with projects outside of plastic moldings. In the early 2000s, Medtronic, a medical device manufacturer, came to them seeking help with developing an angioplasty balloon. The balloon is made of a nylon material that expands and contracts due to temperature and pressure fluctuations. It turns out, modeling the process was very similar to their simulations for bottle molding.
“As we get ever closer to numerically describing and predicting the blowing process from start to finish, we are beginning to be able to optimize the design, and even manufacture, of just about any product configuration,” Menary told us.
The team has not always had all the necessary tools to simulate the ISBM process. As technology evolved, so have their simulations and equipment. The team actually developed its own tools and instruments necessary to create an accurate simulation. Temperature sensors are now used to monitor the materials during their manufacturing process along with pressure sensors, which attach to the moldings during the blowing process. As a result, they now can produce better simulations and have even created a few of their own companies based from their patents they were awarded.