2025 ASEE Annual Conference & Exposition

Stretch Blow Molding Laboratory Using Preform and 3D Printed Mold

Presented at ELOS Technical Session 6: BYOE (Bring Your Own Experiment): Engaging Students with Creative Hands-on Laboratory Experiences

Stretch Blow Molding Laboratory Using Preform and 3D Printed Mold

Blow molding is a useful and intriguing manufacturing process to form plastic parts from a preform. One of the used techniques is stretch blow molding where a heated preform is inflated into desired shape. The most common thermoplastic polymer material used for the blow molding process is Polyethylene Terephthalate (PET). This material was used in the student project for laboratory experiments and simulations.

The stretch blow molding process was selected for this project where undergraduate engineering students used a Dr. Pepper bottle, 3D scanned the same bottle using an Einscan SP scanner, used the scanned file to model the mold in SOLIDWORKS and 3D printed the mold for laboratory experiments using ELEGOO printers. This paper presents details of the 3D scan of the bottle, the design and printing process of the mold and stretch blow molding experiments and simulations. Ansys Polyflow was used by students to run simulations that provided data regarding wall thickness profiles of the product from the same material to the one used by the manufacturer of the 20 fl oz bottle.

The outer and inner diameters of the preform used for simulations and laboratory experiments in this student project were 28 mm and 22 mm, respectively and the length of the preform was 145 mm. The final wall thickness distribution resulting from simulations and experiments were compared with the original bottle and evaluated to determine similarities and differences. Factors contributing to the difference in wall thickness profiles are discussed in the paper. It was concluded that the initial preform used for the experiment achieves the same shaped product as the original bottle.

The findings of this project will be used in a new experimental laboratory setup designed for students to learn more about the concepts related to stretch blow molding. The 3D printed mold from this project will be used in the laboratory experiment with the aim that students focus on observing and studying the factors that affect the wall thickness profiles of the finished product. The Olympus Magna Mike 8500 handheld magnetic thickness gage was used to experimentally perform reliable and repeatable measurements of the thickness profiles for stretch blow molded plastic bottles for comparison with Ansys Polyflow simulations and the original bottle. The paper will also include a description of student outcomes, student involvement and response and an assessment of the student learning procedure.

Authors

Trevont Moore Oral Roberts University [biography]

I am an engineering major with a mechanical concentration in the School of Engineering at Oral Roberts University. I will earn a Bachelor of Science in Engineering in May 2026. I have been drawn to science and math for as long as I can remember, and studying engineering has only furthered my desire for it. I am hungry for more and more knowledge so that I can impact the world for good.
Mr. Jonathan V Ophus Oral Roberts University [biography]

Jonathan Ophus has worked in several facets of the fabrication industry over the last 30 years. He developed several different pieces of equipment and processes for higher yields in the precious metals industry. In the construction industry, he designed equipment and new processes for delivery of 50% stronger concrete to be used in structural applications. He enjoys teaching and working with young people. He currently works with students and faculty at Oral Roberts University’s School of Engineering as a machine shop technician.
Gabriel Pendell Oral Roberts University [biography]

Gabriel Pendell is a senior studying mechanical engineering at Oral Roberts University and will graduate with a bachelors of science in engineering in May. Afterward, he will continue to graduate education at the University of Illinois. His research interests include manufacturing processes, thermal-fluid systems, and combustion.
Michael Portman Oral Roberts University [biography]

Michael is a Senior Engineering major with a mechanical concentration at Oral Roberts University, graduating in May 2025. He looks forward to combining technical knowledge and leadership skills to serve others with engineering.
Jordan Matthew Swan Oral Roberts University [biography]

Submitted in collaboration with Michael Portman, Gabriel Pendell, Manuel Yanez, and Trevont Moore
Manuel Yanez Oral Roberts University [biography]

Manuel Yanez is a 22-year-old mechanical engineering student at Oral Roberts University. Raised primarily in Tulsa, Oklahoma, and spending a significant portion of his teenage years in Mexico, Manuel gained a unique perspective on the technological and engineering disparities between the two countries. This experience fueled his passion for engineering and design, sparking a deeper curiosity about how innovation can transform communities. His bilingual background and practical experience in construction and FRC Robotics influence his engineering approach, blending creativity with technical expertise.
Dr. John E Matsson Oral Roberts University [biography]

John Matsson is a Professor of Mechanical Engineering at Oral Roberts University in Tulsa, OK. He earned M.S. and Ph.D. degrees from the Royal Institute of Technology in Stockholm, Sweden in 1988 and 1994 respectively.

Note

The full paper will be available to logged in and registered conference attendees once the conference starts on June 22, 2025, and to all visitors after the conference ends on June 25, 2025

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