Pushing the limits
The world of 3D printing is a realm of boundless possibilities where innovative minds continuously challenge the limits of this transformative technology. One such pioneer is YouTuber Camden Bowen, who embarked on an extraordinary mission—to 3D print a combustion engine. While Bowen had prior experience crafting engines, they were pumps powered by compressed air. Creating a combustion engine, however, is a far more complex endeavor. It demands a machine that can operate as an autonomous air pump, where fuel— in this case, butane—plays a critical role. Like conventional piston engines, Bowen’s creation compresses a fuel-air mixture, ignites it, expels exhaust, and then intakes fresh fuel.
Yet, 3D printing a combustion engine from plastic presents a unique set of challenges. Certain inherent limitations of the technology must be acknowledged from the outset. For instance, the crankshaft, a vital component, couldn’t be fashioned from plastic. If such a feat were feasible, industry giants like Harbor Freight would have capitalized on it. Additionally, the flywheel required metal infusion to achieve the necessary weight and short segments of copper pipe were substituted for valve seats. Apart from these components, J-B Weld was among the few materials employed that didn’t originate from a 3D printer.
Despite initial ignition challenges, the results were a mixed bag. The engine emitted sporadic pops and bangs but failed to maintain continuous operation. While boasting substantial compression and a reliable ignition system, the Achilles’ heel appeared to be the fuel delivery system—an improvised butane lighter placed in front of the intake port. It’s essential to recognize that crafting a functional plastic engine, particularly one that endures the rigors of combustion, remains an audacious endeavor. The sheer power of internal combustion engines (ICE) underscores their complexity and resilience. These engines are designed to safely contain and harness the energy of controlled explosions within their cylinders. Even metal ICE engines in production vehicles have grappled with issues like cylinder head detachment due to combustion pressure. Some earlier 20th-century engines circumvented this problem by casting the cylinder head as an integral part of the block. The concept of a plastic engine, or even a sturdier injection-molded plastic version, enduring combustion forces for an extended period remains aspirational at best.
Nonetheless, Camden Bowen’s attempt serves as an informative and engaging exploration into the intricacies of internal combustion engines with the aid of 3D printing technology. It offers a unique opportunity to dissect the mechanics and principles that underpin engine functionality—a topic that fewer individuals seem inclined or equipped to delve into in-depth. While the journey may not have yielded a fully operational plastic engine, it undeniably underscores the fascinating potential and learning opportunities that 3D printing brings to engine technology.
Story by Peter Holderith. A 3D-Printed Combustion Engine Made of Plastic Works as You’d Expect.