Large Scale Additive Manufacturing for Global-Scale Home Production using Recycled Polymers

David Hardt, PhD

Ralph E. and Eloise F. Cross Professor of Mechanical Engineering Lab for Manufacturing and Productivity

MIT

Abstract- The problem of inadequate homes or no homes at all afflicts a substantial number of the world's population (~25%) and at present there are no scalable solutions to this problem. At the same time, we are awash in un-recycled polymers, notably PET and HDPE that continue to be produced in very high volumes and have desirable properties for long-term structural use. This project was conceived to create a solution to both problems using the concept of highly distributed micro-factories, each equipped with one or more large scale polymer extrusion additive machines, along with necessary ancillary processes. The goal is to create both highly affordable and desirable dwelling, and at the same time create locally situated wealth producing industries proximal to the needy areas. Lastly, such a system must scale to production levels on the order of 100 million units per year to have an impact. From this concept, numerous research questions arise, including structural design using such polymers, process design for structures of this scale, long term performance of polymer structures in various environments, flammability, and toxicity concerns, and ultimately the economic viability of such a system for both the producer and intended buyers. To achieve the necessary scale and economies a novel global manufacturing system must also be designed and analyzed. In this presentation the initial findings on many of these issues will be presented along with a list of challenging research problems, both fundamental and applied that remain unsolved. Since this presentation will pose more questions than answers, it serves as a case study of how specific research topics can trace their origins to a vision for a solution to critical global issues.

Bio- Professor Hardt has been a member of the Mechanical Engineering faculty since 1979, with a disciplinary focus of system dynamics and control as applied to manufacturing. His teaching currently focuses on engineering design and control manufacturing processes. His research has been on flexible automation, and process control, with an early emphasis on welding and forming processes, and a more recent focus on polymer micro embossing and micro-contact printing. In welding, he pioneered the use of multivariable control techniques for modeling and control of GMAW, and demonstrated the use of adaptive control in these systems. In the forming processes, he has concentrated on the use of in-process measurements and real-time modeling to reduce sensitivity to machine and material variations, and has developed a flexible tooling and closed loop shape control concept for 3D sheet parts. The later has implemented in the aerospace industry with specific uses for repair part manufacture. His more recent work has been in the hot micro-embossing process for micro-fluidic device manufacture in micro-contact process scale-up using roll to roll processes. In both cases the theme of the work is novel equipment design and overall equipment and process statistical control. His current projects include methods for lower cost large scale metal additive manufacturing, and the use of polymer additive methods for the large-scale production of low-cost homes using recycled materials. He has supervised 27 PhD theses, 151 SM theses and 66 Master of Engineering in Advanced Manufacturing and Design Theses and has served on the PhD committees of 47 students. Prof. Hardt served as Director of the MIT Laboratory for Manufacturing from 1985 - 1992 and as Engineering Co-Director for the MIT Leaders for Manufacturing Program from 1993 to 1998, and MIT Director for the Singapore MIT Alliance (SMA) program in Manufacturing Systems and Technology from 1999 to 2014. Prof. Hardt led the creation of a professional graduate degree: Master of Engineering in Advanced Manufacturing and Design (MIT AMD). This is the first professional degree offered by the ME Department at MIT, and is the culmination of many years of course and curriculum development. Recently he led the development of a MicroMaster credential on the EdX platform in the "Principles of Manufacturing" and contributed 2 of the 8 modules that comprise one semester of the MIT MEng in Manufacturing degree. This program has had awarded more than 5000 certificates in the first three years of operation. Prof. Hardt also served as Associate Department Head for Teaching and Graduate Officer in the Mechanical Engineering Department. He currently serves on the Technical Advisory Board of three companies: Digital Alloys, Industrial ML and MyTide Therapeutics.