As facilitators of 3D printer workshops, the authors developed a survey to gage how the printers are actually being used and whether they support the Next Generation Science Standards (NGSS) requirements, especially in regard to engineering design. The survey response rate was 52% of 68 total participants with the majority conveying that 3D printers do facilitate student understanding of the engineering design process and that the workshops empowered them and their students to tackle projects previously perceived as beyond their skill level. Insufficient preparation for troubleshooting hardware and software issues was listed as the greatest barrier to fully realizing the technology’s potential in the classroom. Also highlighted was a lack of resources for development of meaningful lesson plans using this nascent technology.

The recent development of the RepRap, an open-source self-replicating rapid prototyper, has made 3-D polymer-based printers readily available to the public at low costs (<$500). The resultant uptake of 3-D printing technology enables for the first time mass-scale distributed digital manufacturing. RepRap variants currently fabricate objects primarily from acrylonitrile butadiene styrene (ABS) and polylactic acid (PLA), which have melting temperatures low enough to use in melt extrusion outside of a dedicated facility, while high enough for prints to retain their shape at average use temperatures. In order for RepRap printed parts to be useful for engineering applications the mechanical properties of printed parts must be known. This study quantifies the basic tensile strength and elastic modulus of printed components using realistic environmental conditions for standard users of a selection of open-source 3-D printers. The results find average tensile strengths of 28.5 MPa for ABS and 56.6 MPa for PLA with average elastic moduli of 1807 MPa for ABS and 3368 MPa for PLA. It is clear from these results that parts printed from tuned, low-cost, open-source RepRap 3-D printers can be considered as mechanically functional in tensile applications as those from commercial vendors.

STEM is an acronym for science, technology, engineering and mathematics fields of study meant to improve U.S. competitiveness by guiding curriculum and influencing education policy. STEM education begins with K-12 educators, who are struggling with how to implement the Next Generation Science Standards (NGSS) that now place explicit emphasis on the relationship of engineering to science. The NGSS guidelines suggest that science curriculum should have activities with an iterative process involving; defining the problem, developing possible solutions, and optimizing design solutions. The advancements in both open source 3D printing hardware and related open source software has started a revolution in the availability of rapid prototyping technologies to a far larger audience than just practicing engineers and research scientists.

Standard fused filament fabrication (FFF)-based 3-D printers fabricate parts from thermopolymers, such as polylactic acid (PLA). A new range of metal based PLA composites are available providing a novel range of potential engineering materials for such 3-D printers. Currently, limited material data, specifically thermal property characterization is available on these composites. As a result, the application of these materials into functional engineered systems is not possible. This study aims to fill the knowledge gap by quantifying the thermal properties of copperFill, bronzeFill, magnetic iron PLA, and stainless steel PLA composites and provide insight into the technical considerations of FFF composite 3-D printing. Specifically, in this study the correlation of the composite microstructure and printing parameters are explored and the results of thermal conductivity analysis as a function of printed matrix properties are provided. Considering the relative deviation from the filament raw bulk analysis, the results show the printing operation significantly impacts the resultant component density. Experimentally collected thermal conductivity values, however, do not correlate to the theoretical models in the literature and more rigorous quantitative exercises are required to determine true percent porosity to accurately model the effect of air pore volume fraction on thermal conductivity. Despite this limitation, the thermal conductivity values provided can be used to engineer thermal conductivity into 3-D printed parts with these PLA-based composites. Finally, several high-value applications of such 3-D printed materials that look metallic, but have low thermal conductivity are reviewed.

Following the rapid rise of distributed additive manufacturing with 3-D printing has come the technical development of filament extruders and recyclebots, which can turn both virgin polymer pellets and post-consumer shredded plastic into 3-D filament. Similar to the solutions proposed for other forms of ethical manufacturing, it is possible to consider a form of ethical 3-D printer filament distribution being developed. There is a market opportunity for producing this ethical 3-D printer filament, which is addressed in this paper by developing an “ethical product standard” for 3-D filament based upon a combination of existing fair-trade standards and technical and life cycle analysis of recycled filament production and 3-D printing manufacturing. These standards apply to businesses that can enable the economic development of waste pickers and include i) minimum pricing, ii) fair trade premium, iii) labor standards, iv) environmental and technical standards, v) health and safety standards, and vi) social standards including those that cover discrimination, harassment, freedom of association, collective bargaining and discipline.

Nitrate, the most oxidized form of nitrogen, is regulated to protect people and animals from harmful levels as there is a large over abundance due to anthropogenic factors. Widespread field testing for nitrate could begin to address the nitrate pollution problem, however, the Cadmium Reduction Method, the leading certified method to detect and quantify nitrate, demands the use of a toxic heavy metal. An alternative, the recently proposed Environmental Protection Agency Nitrate Reductase Nitrate-Nitrogen Analysis Method, eliminates this problem but requires an expensive proprietary spectrophotometer. The development of an inexpensive portable, handheld photometer will greatly expedite field nitrate analysis to combat pollution. To accomplish this goal, a methodology for the design, development, and technical validation of an improved open-source water testing platform capable of performing Nitrate Reductase Nitrate-Nitrogen Analysis Method. This approach is evaluated for its potential to i) eliminate the need for toxic chemicals in water testing for nitrate and nitrite, ii) reduce the cost of equipment to perform this method for measurement for water quality, and iii) make the method easier to carryout in the field. The device is able to perform as well as commercial proprietary systems for less than 15% of the cost for materials. This allows for greater access to the technology and the new, safer nitrate testing technique.

Simple 3-D printable open source hardware designs have proven to be effective scientific instruments at low costs. Further development in this area is coupling open source electronics with 3-D printable mechanical components to make fully functional distributedly-manufactured mechatronic tools for science. One research area where such low-cost technology is needed is to characterize thin film anti-reflective coatings and transparent conducting oxides (TCOs) for the glass, mirror and solar photovoltaic industry whose transmission properties are angle dependent. To meet this research need a low-cost 3-D printable open source dual axis gimbal system is presented in this study. An Arduino based microcontroller is used to move the sample holder to the user specified angle where two stepper motors control the motion providing two degrees of freedom. The sample holder is made in such a way that samples can easily be mounted on it by two movable latches. The system was validated and characterized for: i) unidirectional accuracy, 1 Preprint: Nupur Bihari, Smruti Prasad Dash, Karankumar C. Dhankani, Joshua M. Pearce. 3-D printable open source dual axis gimbal system for optoelectronic measurements. Mechatronics 56, 175-187 (2018). DOI: https://doi.org/10.1016/j.mechatronics.2018.07.005 ii) repeatability, iii) backlash, iv) speed resolution and v) microstep size. Finally, the mechatronic system is tested for the intended application using a halogen light source and a spectrometer to measure transmission through glass TCO samples through a hemisphere. The system performed as expected has a unidirectional accuracy of 2.827°, repeatability of 1.585°, backlash error of 1.237°, maximum speed of 35.156° and a verifiable microstep size of 0.33°. Despite the highest mean squared errors, the open source gimbal system performed adequately while measuring transmission of radiation through glass with TCO coatings. This open source system also represents a 96% cost in savings as compared to the least expensive commercial variant. The high mean squared errors are offset by the cost of the system coupled with its open source nature that promotes further collaboration and hence, development.

RepRap 3-D printers and their derivatives using conventional firmware are limited by: 1) requiring technical knowledge, 2) poor resilience with unreliable hardware, and 3) poor integration in complicated systems. In this paper, a new control system called Franklin, for CNC machines in general and 3-D printers specifically, is presented that enables web-based three dimensional control of additive, subtractive and analytical tools from any Internet connected device. Franklin can be set up and controlled entirely from a web interface; it uses a custom protocol which allows it to continue printing when the connection is temporarily lost, and allows communication with scripts.

The release of the open source 3-D printer known as the RepRap (a self-Replicating Rapid prototyper) resulted in the potential for distributed manufacturing of products for significantly lower costs than conventional manufacturing. This development, coupled with open source-appropriate technology (OSAT), has enabled the opportunity for 3-D printers to be used for sustainable development. In this context, OSAT provides the opportunity to modify and improve the physical designs of their printers and desired digitally-shared objects. However, these 3-D printers require electricity while more than a billion people still lack electricity. To enable the utilization of RepRaps in off-grid communities, solar photovoltaic (PV)-powered mobile systems have been developed, but recent improvements in novel delta-style 3-D printer designs allows for reduced costs and improved performance. This study builds on these innovations to develop and experimentally validate a mobile solar-PV-powered delta 3-D printer system. It is designed to run the RepRap 3-D printer regardless of solar flux. The electrical system design is tested outdoors for operating conditions: (1) PV charging battery and running 3-D printer; (2) printing under low insolation; (3) battery powering the 3-D printer alone; (4) PV charging the battery only; and (5) battery fully charged with PV-powered 3-D printing. The results show the system performed as required under all conditions providing feasibility for adoption in off-grid rural communities. 3-D printers powered by affordable mobile PV solar systems have a great potential to reduce poverty through employment creation, as well as ensuring a constant supply of scarce products for isolated communities.