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This paper is a “Q&A interview” conducted by Joanne Pransky of Industrial Robot Journal as a method to impart the combined technological, business and personal experience of a prominent, robotic industry PhD and innovator regarding his personal journey and the commercialization and challenges of bringing a technological invention to market. This paper aims to discuss these issues.

The interviewee is Dr Hod Lipson, James and Sally Scapa Professor of Innovation of Mechanical Engineering and Data Science at Columbia University. Lipson’s bio-inspired research led him to co-found four companies. In this interview, Dr Lipson shares some of his personal and business experiences of working in academia and industry.

Dr Lipson received his BSc in Mechanical Engineering from the Technion Israel Institute of Technology in 1989. He worked as a software developer and also served for the next five years as a Lieutenant Commander for the Israeli Navy. He then co-founded his first company, Tri-logical Technologies (an Israeli company) in 1994 before pursuing a PhD, which was awarded to him from the Technion Israel Institute of Technology in Mechanical Engineering in the fall of 1998. From 1998 to 2001, he did his postdoc research at Brandeis University, Computer Science Department, while also lecturing at MIT. Dr Lipson served as Professor of Mechanical & Aerospace Engineering and Computing & Information Science at Cornell University for 14 years and joined Columbia University as a Professor in Mechanical Engineering in 2015. From 2013 to 2015, he also served as Editor-in-Chief for the journal 3D Printing and Additive Manufacturing (3DP), published by Mary Ann Liebert Inc.

Dr Lipson’s broad spectrum and multi-decades of research has focused on self-aware and self-replicating robots. Dr Lipson directs the Creative Machines Lab which pioneers new ways for novel autonomous systems to design and make other machines, based on biological concepts. In total, his lab has graduated over 50 graduate students and over 20 PhD and Postdocs. Some of these students joined Lipson, in cofounding startups, while others went on to found their own companies. Lipson has coauthored over 300 publications that received over 20,000 citations. He has also coauthored the award-winning book Fabricated: The New World of 3D Printing and the book Driverless: Intelligent Cars and the Road Ahead. Forbes magazine named him one of the “World's Most Powerful Data Scientists”. His TED Talk on self-aware machines is one of the most viewed presentations on AI and robotics.

Digital materials are composed of many discrete voxels placed in a massively parallel layer deposition process, as opposed to continuous (analog) deposition techniques. The purpose of this paper is to explore the wide range of material properties attainable using a voxel‐based freeform fabrication process, and demonstrate in simulation the versatility of fabricating with multiple materials in this manner.

A representative interlocking voxel geometry was selected, and a nonlinear physics simulator was implemented to perform virtual tensile tests on blocks of assembled voxels of varying materials. Surface contact between tiles, plastic deformation of the individual voxels, and varying manufacturing precision were all modeled.

By varying the precision, geometry, and material of the individual voxels, continuous control over the density, elastic modulus, coefficient of thermal expansion, ductility, and failure mode of the material is obtained. Also, the effects of several hierarchical voxel “microstructures” are demonstrated, resulting in interesting properties such as negative Poisson's ratio.

This analysis is a case study of a specific voxel geometry, which is representative of 2.5D interlocking shapes but not necessarily all types of interlocking voxels.

The results imply that digital materials can exhibit widely varying and tunable properties in a single desktop fabrication process.

The paper explores the vast potential of tunable materials, especially using the concept of voxel microstructure, applicable primarily to 3D voxel printers but also to other multi‐material freeform fabrication processes.

The paper's aim is to show the development of materials and methods which allow freeform fabrication of macroscopic Zn‐air electrochemical batteries. Freedom of geometric design may allow for new possibilities in performance optimization.

The authors have formulated battery materials which are compatible with solid freeform fabrication (SFF) while retaining electrochemical functionality. Using SFF processes, they have fabricated six Zn‐air cylindrical batteries and quantitatively characterized them and comparable commercial batteries. They analyze their performance in light of models from the literature and they also present SFF of a flexible two‐cell battery of unusual geometry.

Under continuous discharge to 0.25 V/cell with a 100 Ω load, the cylindrical cells have a specific energy and power density in the range of 40‐70 J/g and 0.4‐1 mW/cm², respectively, with a mass range of 8‐18 g. The commercial Zn‐air button cells tested produce 30‐750 J/g and 7‐9 mW/cm² under the same conditions, and have a mass range of 0.2‐2 g. The two‐cell, flexible Zn‐air battery produces a nominal 2.8 V, open‐circuit.

The freeform‐fabricated batteries have ∼10 percent of the normalized performance of the commercial batteries. High‐internal contact resistance, loss of electrolyte through evaporation, and inferior catalyst reagent quality are possible causes of inferior performance. Complicated material preparation and battery fabrication processes have limited the number of batteries fabricated and characterized, limiting the statistical significance of the results.

Performance enhancement will be necessary before the packaging efficiency and design freedom provided by freeform‐fabricated batteries will be of practical value.

The paper demonstrates a multi‐material SFF system, material formulations, and fabrication methods which together allow the fabrication of complete functional Zn‐air batteries. It provides the first quantitative characterization of completely freeform‐fabricated Zn‐air batteries and comparison to objective standards, and shows that highly unusual, functional battery designs incorporating flexibility, multiple cells, and unusual geometry may be freeform fabricated.

Virtual voxels (3D pixels) have traditionally been used as a graphical data structure for representing 3D geometry. The purpose of this paper is to study the use of pre‐existing physical voxels as a material building‐block for layered manufacturing and present the theoretical underpinnings for a fundamentally new massively parallel additive fabrication process in which 3D matter is digital. The paper also seeks to explore the unique possibilities enabled by this paradigm.

Digital RP is a process whereby a physical 3D object is made of many digital units (voxels) arranged selectively in a 3D lattice, as opposed to analog (continuous) material commonly used in conventional rapid prototyping. The paper draws from fundamentals of 3D space‐filling shapes, large‐scale numerical simulation, and a survey of modern technology to reach conclusions on the feasibility of a fabricator for digital matter.

Design criteria and appropriate 3D voxel geometries are presented that self‐align and are suitable for rapid parallel assembly and economical manufacturing. Theory and numerical simulation predict dimensional accuracy to scale favorably as the number of voxels increases. Current technology will enable rapid parallel assembly of billions of microscale voxels.

Many novel voxel functions could be realized in the electromechanical and microfluidic domains, enabling inexpensive prototyping of complex 3D integrated systems. The paper demonstrates the feasibility of a 3D digital fabricator, but an instantiation is out of scope and left to future work.

Digital manufacturing offers the possibility of desktop fabrication of perfectly repeatable, precise, multi‐material objects with microscale accuracy.

The paper constitutes a comprehensive review of physical voxel‐based manufacturing and presents the groundwork for an emerging new field of additive manufacturing.

To seek to produce low‐voltage, soft mechanical actuators entirely via freeform fabrication as part of a larger effort to freeform fabricate complete electromechanical devices with lifelike and/or biocompatible geometry and function.

The authors selected ionomeric polymer‐metal composite (IPMC) actuators from the literature and the authors' own preliminary experiments as most promising for freeform fabrication. The authors performed material formulation and manual device fabrication experiments to arrive at materials which are amenable to robotic deposition and developed an SFF process which allows the production of complete IPMC actuators and their fabrication substrate integrated within other freeform fabricated devices. The authors freeform fabricated simple IPMC's, explored some materials/performance interactions, and preliminarily characterized these devices in comparison to devices produced by non‐SFF methods.

Freeform fabricated IPMC actuators operate continuously in air for more than 4 h and 3,000 bidirectional actuation cycles. The output stress scaled to input power is one to two orders of magnitude inferior to that of non‐SFF devices. Much of this difference may be associated with process‐sensitive microstructure of materials. Future work will investigate this performance gap.

Device performance is sufficient to continue exploration of SFF of complete electromechanical devices, but will need improvement for broader application. The feasibility of the approach for producing devices with complex, non‐planar geometry has not been demonstrated.

This work demonstrates the feasibility of freeform fabricating IPMC devices, and lays groundwork for further development of the materials and methods.

This work constitutes the first demonstration of complete, functional, IPMC actuators produced entirely by freeform fabrication.

New applications of solid freeform fabrication (SFF) are arising, such as functional rapid prototyping and in situ fabrication, which push SFF to its limits in terms of geometrical fidelity due to the applications' inherent process uncertainties. Current closed‐loop feedback control schemes monitor and manipulate SFF techniques at the process level, e.g. envelope temperature, feed rate. “Closing the loop” on the process level, instead of the overall part geometry level, leads to limitations in the types of errors that can be detected and corrected. The purpose of this paper is to propose a technique called greedy geometric feedback (GGF) control which “closes the loop” on the overall part geometry level.

The overall part geometry is monitored throughout the print and, using a greedy algorithm, real‐time decisions are made to serially determine the locations of subsequent droplets, i.e. overall part geometry is directly manipulated. A computer simulator and a physical experimental platform were developed to compare the performance of GGF to an open‐loop control scheme. Root mean square surface height errors were measured under controlled uncertainties in droplet height, droplet radius of curvature, droplet positioning and mid‐print part deformations.

The GGF technique outperformed open‐loop control under process uncertainties in droplet shape, droplet placement and mid‐print part deformations. The disparity between performances is dependant on the nature and extent of the imposed process uncertainties.

Future research will focus on improving the performance of GGF for specific cases by designing more complex greedy algorithmic scoring heuristics. Also, the technique will be generalized beyond heightmap representations of 3D spaces.

The GGF technique is the first to “close the loop” on the overall part geometry level. GGF, therefore, can compensate for a broader range of errors than existing closed‐loop feedback control schemes. Also, since the technique only requires the real‐time update of a very limited set of heights, the technique is computationally inexpensive and widely applicable. By developing a closed‐loop feedback scheme that addressed part geometry‐level errors, SFF can be applied to more challenging in situ fabrication scenarios with less conventional materials.

Solid freeform fabrication (SFF) has the potential to revolutionize manufacturing, even to allow individuals to invent, customize, and manufacture goods cost‐effectively in their own homes. Commercial freeform fabrication systems – while successful in industrial settings – are costly, proprietary, and work with few, expensive, and proprietary materials, limiting the growth and advancement of the technology. The open‐source Fab@Home Project has been created to promote SFF technology by placing it in the hands of hobbyists, inventors, and artists in a form which is simple, cheap, and without restrictions on experimentation. This paper aims to examine this.

A simple, low‐cost, user modifiable freeform fabrication system has been designed, called the Fab@Home Model 1, and the designs, documentation, software, and source code have been published on a user‐editable “wiki” web site under the open‐source BSD License. Six systems have been built, and three of them given away to interested users in return for feedback on the system and contributions to the web site.

The Fab@Home Model 1 can build objects comprising multiple materials, with sub‐millimeter‐scale features, and overall dimensions larger than 20 cm. In its first six months of operation, the project has received more than 13 million web site hits, and media coverage by several international news and technology magazines, web sites, and programs. Model 1s are being used in a university engineering course, a Model 1 will be included in an exhibit on the history of plastics at the Science Museum London, UK, and kits can now be purchased commercially.

The ease of construction and operation of the Model 1 has not been well tested. The materials cost for construction (US$2,300) has prevented some interested people from building systems of their own.

The energetic public response to the Fab@Home project confirms the broad appeal of personal freeform fabrication technology. The diversity of interests and desired applications expressed by the public suggests that the open‐source approach to accelerating the expansion of SFF technology embodied in the Fab@Home project may well be successful.

Fab@Home is unique in its goal of popularizing and advancing SFF technology for its own sake. The RepRap project in the UK predates Fab@Home, but aims to build machines which can make most of their own parts. The two projects are complementary in many respects, and fruitful exchanges of ideas and designs between them are expected.

This paper reports on a fabrication platform and extensions to deposition‐based processes that permit freeform fabrication of three‐dimensional functional assemblies with embedded conductive wiring and power sources. Structure and joints are produced by fused deposition of thermoplastics and deposition of elastomers. Conductive wiring is achieved by deposition of various low‐melting‐point alloys and conductive pastes. Batteries based on zinc‐air chemistry are produced by the deposition of zinc, electrolyte, and catalysts, with separator media and electrodes. Details of the deposition processes are provided and several printed assemblies are demonstrated.

The purposes of this paper are to study how entry-level 3D printers are currently being used in several shared machine shops (FabLabs, hackerspaces, etc.) and to examine the ambivalent emancipation often offered by 3D printing, when users prefer the fascinated passivity of replicating rather than the action of repairing. Based on a field study and on a large online survey, this paper offers to examine different practices with entry-level 3D printers, observed in several shared machine shops (FabLabs, hackerspaces, etc.). The recent evolution of additive manufacturing and the shift from high-end additive technologies to consumer’s entry-level 3D printing is taken as an entry point. Indeed, digital fabrication has recently received extensive media coverage and the maker movement has become a trendy subject for numerous influential publications. In the makerspaces that were taken for this field survey, 3D printers were very often used for demonstration, provoking fascination and encouraging a passive attitude.

As part of the work for a PhD research on personal digital fabrication as practiced in FabLabs, hackerspaces and makerspaces, since 2012, a large-scale field survey at the heart of these workshops was carried out. Particular attention has been paid to the relationships established between the inhabitants of these places and their machines, observing the logic of developing projects and the reactions or techniques used to counter unforeseen obstacles – that shall be demonstrated to be an essential occurrence for these moments of production. From Paris to Amsterdam, Barcelona, Rome, Lyngen (Norway), San Francisco, New York, Boston, Tokyo, Kamakura (Japan) to Dakar, a means of observing at the heart of more than 30 makerspaces (FabLabs, hackerspaces) has been created, with the aim of looking beyond the speeches relayed by the media and to constitute an observatory of these places. The field observations are confirmed by a quantitative study, based on a survey submitted online to 170 users, coming from 30 different makerspaces in more than ten countries in the world and reached through social networks or mailing lists. This survey offers a rigorous insight on the uses of 3D printing and leads to the consideration of the types of attention applied to 3D printing and the part played by the “default” or “trivial” productions used for their demonstrations or performances.

Based on both the observations and the quantitative survey, it can be discussed how the question of so-called “user-friendliness” is challenged by practices of repairing, fixing and adjusting, more than that of replicating. Indeed, it is claimed that this offers a possible meaning for 3D printing practices. In the description and analysis of the behaviours with 3D printers, this leads to privilege the idea of “disengaging” and the notion of “acting” rather than simply passively using.

3D printing is just one of the many options in the wide range available for personal digital fabrication. As a part of the same arsenal as laser cutters or numerical milling machines, 3D printing shares with these machines the possibility of creating objects from designs or models produced by a computer. These machines execute the instructions of operators whose practices – or behaviours – have yet to be qualified. These emerging technical situations pose a series of questions: who are those who use these 3D printers? What are they printing? What are the techniques, the gestures or the rituals imposed or offered by these machines?