The high cost of what have historically been sophisticated research-related sensors and tools has limited their adoption to a relatively small group of well-funded researchers. This paper provides a methodology for applying an open-source approach to design and development of a colorimeter. A 3-D printable, open-source colorimeter utilizing only open-source hardware and software solutions and readily available discrete components is discussed and its performance compared to a commercial portable colorimeter. Performance is evaluated with commercial vials prepared for the closed reflux chemical oxygen demand (COD) method. This approach reduced the cost of reliable closed reflux COD by two orders of magnitude making it an economic alternative for the vast majority of potential users. The open-source colorimeter demonstrated good reproducibility and serves as a platform for further development and derivation of the design for other, similar purposes such as nephelometry. This approach promises unprecedented access to sophisticated instrumentation based on low-cost sensors by those most in need of it, underdeveloped and developing world laboratories.

Please cite this article as: Wittbrodt B, Pearce JM, The Effects of PLA Color on Material Properties of 3-D Printed Components, Addit Manuf (2015), http://dx. AbstractAs the number of prosumer printers has expanded rapidly, they now make up the majority of the 3-D printer market and of these printers those in the open-source lineage of the RepRap also have expanded to dominate. Although still primarily used for prototyping or hobbyist production of low-value products, the RepRap has the capacity to be used for high-value distributed manufacturing. A recent study found that RepRap printed parts printed in realistic environmental conditions can match and even out perform commercial 3-D printers using proprietary FDM in terms of tensile strength with the same polymers. However, tensile strengths of the large sample set of RepRap prints fluctuated. In order to explain that fluctuation and better inform designers on RepRap print properties this study determines the effect of color and processing temperature on material properties of Lulzbot TAZ deposited PLA in various colors. Five colors (white, black, blue, grey, and natural) of commercially available filament processed from 4043D PLA is tested for for crystallinity with XRD, tensile strength following ASTM D638 and the microstructure is evaluated with environmental scanning electron microscope. Results are presented showing a strong relationship between tensile strength and percent crystallinity of a 3-D printed sample and a strong relationship between percent crystallinity and the extruder temperature. Conclusions are drawn about the effects of color and processing temperature on the material properties of 3-D printed PLA to promote the open-source development of RepRap 3-D printing.

3D printing functional parts with known mechanical properties is challenging using variable open source 3D printers. This study investigates the mechanical properties of 3D printed parts using a commercial open-source 3D printer for a wide range of materials. The samples are tested for tensile strength following ASTM D638. The results are presented and conclusions are drawn about the mechanical properties of various fused filament fabrication materials. The study demonstrates that the tensile strength of a 3D printed specimen depends largely on the mass of the specimen, for all materials. Thus, to solve the challenge of unknown print quality on mechanical properties of a 3D printed part a two step process is proposed, which has a reasonably high expectation that a part will have tensile strengths described in this study for a given material. First, the exterior of the print is inspected visually for sub-optimal layers. Then, to determine if there has been under-extrusion in the interior, the mass of the sample is measured. This mass is compared to the theoretical value using densities for the material and the volume of the object. This two step process provides a means to assist low-cost open-source 3D printers expand the range of object production to functional parts.

Although the trend in manufacturing has been towards centralization to leverage economies of scale, the recent rapid technical development of open-source 3-D printers enables low-cost distributed bespoke production. This paper explores the potential advantages of a distributed manufacturing model of high-value products by investigating the application of 3-D printing to self-refraction eyeglasses. A series of parametric 3-D printable designs is developed, fabricated and tested to overcome limitations identified with mass-manufactured self-correcting eyeglasses designed for the developing world's poor. By utilizing 3-D printable self-adjustable glasses, communities not only gain access to far more diversity in product design, as the glasses can be customized for the individual, but 3-D printing also offers the potential for significant cost reductions. The results show that distributed manufacturing with open-source 3-D printing can empower developing world communities through the ability to print less expensive and customized self-adjusting eyeglasses. This offers the potential to displace both centrally manufactured conventional and self-adjusting glasses while completely eliminating the costs of the conventional optics correction experience, including those of highly-trained optometrists and ophthalmologists and their associated equipment. Although, this study only analyzed a single product, it is clear that other products would benefit from the same approach in isolated regions of the developing world.

For the first time, low-cost open-source 3-D printing provides the potential for distributed manufacturing at the household scale of customized, high-value, and complex products. To explore the potential of this type of ultra-distributed manufacturing, which has been shown to reduce environmental impact compared to conventional manufacturing, this paper presents a case study of a 3-D printable parametric design for recreational vehicle (RV) solar photovoltaic (PV) racking systems. The design is a four-corner mounting device with the ability to customize the tilt angle and height of the standoff. This enables performance optimization of the PV system for a given latitude, which is variable as RVs are geographically mobile. The open-source 3-D printable designs are fabricated and analyzed for print time, print electricity consumption, mechanical properties, and economic costs. The preliminary results show distributed manufacturing of the case study product results in an order of magnitude reduction in economic cost for equivalent products. In addition, these cost savings are maintained while improving the functionality of the racking system. The additional electrical output for a case study RV PV system with improved tilt angle functionality in three representative locations in the U.S. was found to be on average over 20% higher than that for conventional mass-manufactured racking systems. The preliminary results make it clear that distributed manufacturing -even at the household level -with open-source 3-D printers is technically viable and economically beneficial. Further research is needed to expand the results of this preliminary study to other types of products.

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.

The purpose of this paper is to provide a technical and economic evaluation of the value of the RepRap as an entry-level 3-D printer in the developing world and provide a cost effective solar photovoltaic (PV) racking solution to better serve the developing world and aid in the acceleration of their economic and socioeconomic growth. A customizable open-source PV racking concept is designed, prototyped for three types of modules, constructed into systems, and outdoor tested under extreme conditions for one year. An economic analysis is provided along with a technical evaluation of the system, which found the proposed racking system can be successfully printed with RepRap 3-D printers and saves between 85% and 92% from commercially available alternatives depending on the plastic used for printing. In addition, the plastic parts proved able to withstand some of the harshest outdoor conditions and due to the free and open-source nature of the designs, it allows the system to be adapted to custom applications in any region in the world more easily than any commercial alternatives. The results indicate that the 3-D printable X-wire solar photovoltiac racking system has the potential to aid in the acceleration of solar deployment in the developing world by providing a low cost PV racking solution.

The economics in the U.S. of solar photovoltaic (PV) systems is changing rapidly as the cost per unit power of PV modules has dropped quickly. These costs reductions have two important results: marked decrease in levelized cost of electricity (LCOE) into ranges competitive or better than traditional electricity-generation technologies and the economic role of racking has been gaining prominence relative to that of modules. As the relative importance of costs of PV racking has been marginal historically, there has been relatively little progress on reducing the materials and costs associated with it, which has caused racking to contribute to a significant portion of costs of entire PV systems. In order to overcome this challenge this study investigates a novel low-weight PV racking system for commercial rooftops based on crossed cables (X-wires) and compares it to racking systems already available on the market on capital costs, labor costs for installation, and technical specifications such as adaptability and power packing factor. The results of over 80% cost reduction and 33% increase in power density are presented and conclusions are drawn about the potential for tension-based racking systems to further reduce total PV systems costs on commercial flat roof tops resulting in LCOE savings of $0.01-$0.02/kW h.