Search

In the material extrusion process, dimensional accuracy and printing time depend on the printing process parameters. Due to consistent layer height, traditional material extrusion takes a long time to print at low-thick layers. The current research proposes a novel way to print low-layer thickness at crucial dimensions and alter the RepRap flavor G code to print the rest with a higher-layer thickness. The current research has decreased printing time by 22.5% over the conventional material extrusion process. This work also presents a novel approach for Z-direction dimensional accuracy. The slicing software determines the total number of printing layers based on the material extrusion thickness and the model's total height. When the total number of layers results in decimals, the decision to print a decimal layer depends on the percentage of the decimal value in the layer thickness. This study found that if the percentage of the decimal value is equal to or more than half of the layer height, slicing software will accommodate a layer; in this case, the final height of the part will be oversized. If it is less than half of the layer height, slicing software won't accommodate the layer; in this case, the height of the part will be undersized. Adopting this method improves dimensional accuracy in the Z direction by editing the code for decimal value, and optimizes material and energy consumption for oversized components. Similarly, the component's linear dimensions are determined by layer width and extrusion percentage. If the extrusion percentage increases, the linear dimensions of the component will also increase. This approach can be used on all geometrical shapes and materials to print critical dimensions with a lower layer thickness and the rest with a higher layer thickness. The printing process parameters, type of material, and geometry complexity do not affect the method's efficiency. [ABSTRACT FROM AUTHOR]

Open-source 3-D printing has played a pivotal role in revolutionizing the additive manufacturing (AM) landscape by making distributed manufacturing economic, democratizing access, and fostering far more rapid innovation than antiquated proprietary systems. Unfortunately, some 3-D printing manufacturing companies began deviating from open-source principles and violating licenses for the detriment of the community. To determine if a pattern has emerged of companies patenting clearly open-source innovations, this study presents three case studies from the three primary regions of open-source 3-D printing development (EU, U.S., and China) as well as three aspects of 3-D printing technology (AM materials, an open-source 3-D printer, and core open-source 3-D printing concepts used in most 3-D printers). The results of this review have shown that non-inventing entities, called patent parasites, are patenting open-source inventions already well-established in the open-source community and, in the most egregious cases, commercialized by one (or several) firm(s) at the time of the patent filing. Patent parasites are able to patent open-source innovations by using a different language, vague patent titles, and broad claims that encompass enormous swaths of widely diffused open-source innovation space. This practice poses a severe threat to innovation, and several approaches to irradicate the threat are discussed. [ABSTRACT FROM AUTHOR]

Low-cost high-resolution metal 3-D printing remains elusive for the scientific community. Low-cost gas metal arc wire (GMAW)-based 3-D printing enables wire arc additive manufacturing (WAAM) for near net shape applications, but has limited resolution due to the complexities of the arcing process. To begin to monitor and thus control these complexities, the initial designs of the open source GMAW 3-D printer have evolved to include current and voltage monitoring. Building on this prior work, in this study, the design, fabrication and use of the open source arc analyzer is described. The arc analyzer is a multi-sensor monitoring system for quantifying the processing during WAAM, which includes voltage, current, sound, light intensity, radio frequency, and temperature data outputs. The open source arc analyzer is tested here on aluminum WAAM by varying wire feed rate and measuring the resultant changes in the sensor data. Visual inspection and microstructural analysis of the printed samples looking for the presence of porosity are used as the physical indicators of quality. The value of the sensors was assessed and the most impactful sensors were found to be the light and radio frequency sensors, which showed arc extinction events and a characteristic “good weld” peak frequency.

To assist firefighters and other first responders to use their existing equipment for respiration during the COVID-19 pandemic without using single-use, low-supply, masks, this study outlines an open source kit to convert a 3M-manufactured Scott Safety self-contained breathing apparatus (SCBA) into a powered air-purifying particulate respirator (PAPR). The open source PAPR can be fabricated with a low-cost 3-D printer and widely available components for less than $150, replacing commercial conversion kits saving 85% or full-fledged proprietary PAPRs saving over 90%. The parametric designs allow for adaptation to other core components and can be custom fit specifically to fire-fighter equipment, including their suspenders. The open source PAPR has controllable air flow and its design enables breathing even if the fan is disconnected or if the battery dies. The open source PAPR was tested for air flow as a function of battery life and was found to meet NIOSH air flow requirements for 4 h, which is 300% over expected regular use.

Thermal sterilization is generally avoided for 3-D printed components because of the relatively low deformation temperatures for common thermoplastics used for material extrusion-based additive manufacturing. 3-D printing materials required for high-temperature heat sterilizable components for COVID-19 and other applications demands 3-D printers with heated beds, hot ends that can reach higher temperatures than polytetrafluoroethylene (PTFE) hot ends and heated chambers to avoid part warping and delamination. There are several high temperature printers on the market, but their high costs make them inaccessible for full home-based distributed manufacturing required during pandemic lockdowns. To allow for all these requirements to be met for under $1000, the Cerberus – an open source three-headed self-replicating rapid prototyper (RepRap) was designed and tested with the following capabilities: i) 200 °C-capable heated bed, ii) 500 °C-capable hot end, iii) isolated heated chamber with 1 kW space heater core and iv) mains voltage chamber and bed heating for rapid start. The Cereberus successfully prints polyetherketoneketone (PEKK) and polyetherimide (PEI, ULTEM) with tensile strengths of 77.5 and 80.5 MPa, respectively. As a case study, open source face masks were 3-D printed in PEKK and shown not to warp upon widely home-accessible oven-based sterilization.

The application of 3D printing by fused deposition modeling (FDM) and the low-cost RepRap 3D printer for the processing of poly-l-lactide (PLLA) and poly(l-lactide-co-trimethylene carbonate) (PLLATMC) blends was examined. Two blends with different mechanical properties were selected and the general scheme of their processing was proposed. For 80:20 PLLA:PLLATMC blend, fused filament fabrication (FFF) and the standard configuration of 3D printer were used, whereas for 30:70 PLLA:PLLATMC, the device was modified based on custom project for the application of fused granulate fabrication (FGF). The properties of the blends and their changes during the processing were analyzed by rheological measurements and size exclusion chromatography. Selected parameters of the printing process were optimized and their influence on the quality of the product was discussed. Both methods were used for the preparation of the scaffolds with different previously designed structures. The geometry of the scaffolds was characterized in relation to the parameters of the printing process, and base on this, the accuracy and precision of FFF and FGF methods were evaluated. [ABSTRACT FROM AUTHOR]

To provide process optimization of metal fabricating self-replicating rapid prototyper (RepRap) 3-D printers requires a low-cost sensor and data logger system to measure current (I) and voltage (V) of the gas metal arc welders (GMAW). This paper builds on previous open-source hardware development to provide a real-time measurement of welder I-V where the measuring circuit is connected to two analog inputs of the Arduino that is used to control the 3-D printer itself. Franklin firmware accessed through a web interface that is used to control the printer allows storing the measured values and downloading those stored readings to the user’s computer. To test this custom current and voltage monitoring device this study reports on its use on an upgraded all metal RepRap during the printing of aluminum alloy (ER1100, ER4043, ER4943, ER4047, and ER5356). The voltage and current data were analyzed on a per alloy basis and also layer-by-layer in order to evaluate the device’s efficacy as a monitoring device for 3-D printing and the results of the integrated design are discussed.

The open source introduction of fused filament fabrication (FFF) enables distributed manufacturing of consumer products. However, with a wide range of low-cost FFF 3-D printers and settings possible, there is a lack of information on the variability in printed mechanical properties. This paper utilizes a large pool of 47 user-assembled 3-D printers to quantify the mechanical property variations of ultimate tensile strength (UTS) and yield strength of FFF printed components using ASTM D638-14 horizontally-oriented Type I and IV geometries for poly lactic acid (PLA). The results indicate that utilizing Type IV tensile test piece geometry may overestimate the UTS relative to the Type I. Furthermore, anisotropic mechanical property variances were quantified for Type IV specimens (vertical and horizontal orientations). Vertical tensile specimens had an ultimate tensile strength 47.9% less than horizontal. Finally, the abundant supply of PLA 3-D prints suggest open-source printers assembled by individual operators can produce quality plastic components although the mechanical performance of the given part can vary dramatically based on the operator selection of printing parameters that provide a visually acceptable part. [ABSTRACT FROM AUTHOR]

As low-cost desktop 3D printing is now dominated by free and open source self-replicating rapid prototype (RepRap) derivatives, there is an intense interest in extending the scope of potential applications to manufacturing. This study describes a manufacturing technology that enables a constrained set of polymer-metal composite components. This paper provides (1) free and open source hardware and (2) software for printing systems that achieves metal wire embedment into a polymer matrix 3D-printed part via a novel weaving and wrapping method using (3) OpenSCAD and parametric coding for customized g-code commands. Composite parts are evaluated from the technical viability of manufacturing and quality. The results show that utilizing a multi-polymer head system for multi-component manufacturing reduces manufacturing time and reduces the embodied energy of manufacturing. Finally, it is concluded that an open source software and hardware tool chain can provide low-cost industrial manufacturing of complex metal-polymer composite-based products. [ABSTRACT FROM AUTHOR]

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, under-developed and developing world laboratories.

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.

Nowadays the technologies originally developed only for prototype production are involved among modern production techniques. This trend is induced mainly by developing of new materials and very effective improvement of rapid prototyping production methods and tools. The resulting mechanical properties of the products are now fully comparable with the properties of parts produced with using the technologies modified for batch production (e.g. injection moulding or blow moulding etc.). This article deals with comparing the flexural and tensile properties of specimens produced by injection moulding technology and by FDM technology, particularly using three different 3D printers (Dimension SST 768, Fortus 450 and Rep Rap). The part orientation within the build envelope of selected FDM machines is another aspect that was evaluated and that had significant impact on part behaviour of printed parts. All the analysed specimens were made of thermoplastic ABS. [ABSTRACT FROM AUTHOR]

The research presented in this article deals with the design of appropriate technology and with an implementation of the structural design of the 3D printer for use in gastronomy. A printer concept of RepRap open source project was used and completed with own solution of the extrusion head for printing with chocolate. Chocolate was chosen since it can be easily converted by heat into a plastic-like material and displaced through an extruder on a substrate. Thanks to that, you can print business cards made of chocolate, pralines in shape of whatever the customer desires, or portraits. The printer can also be used for other materials, such as different toppings on cakes, or very complicated structures that would not be possible to create without using 3D printing. [ABSTRACT FROM AUTHOR]

Additive manufacturing with 3-D printers may be a key technology enabler for entrepreneurs seeking to use disruptive innovations such as business models utilizing distributed manufacturing. Unlike centralized manufacturing, distributed manufacturing makes the parts and products (the prints) at (or closer to) the source of the demand, cutting out much of the traditional supply chain. Although many expect 3-D printing to take off at the household level and previous work has shown significant returns for those choosing to do so, there are still significant barriers to entry for typical consumers. Our analysis demonstrates that for an individual to make an abnormally high return on their investments in 3-D printers, they must serve others to achieve high utilization rates. The impetus to do so is created by a service that can undercut traditionally manufactured products due to affordability and customizability. Low-cost, open-source 3-D printers are now priced within range of individual entrepreneurs who can take advantage of the long tail of consumers with highly varied interests. The margin advantage, net present value, and return on investment (ROI) analysis provided herein could form the basis of thousands of new small-business ventures in the coming years. [ABSTRACT FROM AUTHOR]

The aim of this paper is to analyze the performance of a RepRap 3D printer liquefier by studying its thermal behavior, focusing on the convective heat dissipation developed along the liquefier body during the 3D printing process of a workpiece. More specifically, this work tackles with the influence of the airflow generated by a fan coupled to the extruder, on the heat transfer mechanisms during the printing process. The airflow is thus taken as the variable of study. The temperature at the top of the liquefier body, where a low temperature is desirable for the correct preservation of the 3D printer components, is analyzed to assess the results for the different printing conditions. For the development of this study, a finite elements model was used to determine the theoretical temperature profile of the liquefier in a steady state working regime. This mathematical model was then validated with experimental data registered with four thermocouples fixed on the tested extruder. The data was taken for different airflows, finding a relation between printing parameters and resulting temperature profile. The liquefier used for experimental data acquisition was the BCNozzle model, designed by the BCN3D Technologies of the Polytechnic University of Catalonia. Determining the correct working parameters is necessary to optimize the fused filament fabrication process on which 3D printing is based, ensuring a suitable temperature distribution along the liquefier body. This would allow a correct position of the melting front along the liquefier channel, and at the same time, a non-excessive temperature at its top, next to the feeding mechanism. This is the relevance of this study, through which a model is obtained to analyze the heat transfer mechanisms, applicable for other working regimes and other extruders based on the same working principles. [ABSTRACT FROM AUTHOR]

The cancer stem cell (CSC) population displays self-renewal capabilities, resistance to conventional therapies, and a tendency to post-treatment recurrence. Increasing knowledge about CSCs’ phenotype and functions is needed to investigate new therapeutic strategies against the CSC population. Here, poly(ε-caprolactone) (PCL), a biocompatible polymer free of toxic dye, has been used to fabricate scaffolds, solid structures suitable for 3D cancer cell culture. It has been reported that scaffold cell culture enhances the CSCs population. A RepRap BCN3D+ printer and 3 mm PCL wire were used to fabricate circular scaffolds. PCL design and fabrication parameters were first determined and then optimized considering several measurable variables of the resulting scaffolds. MCF7 breast carcinoma cell line was used to assess scaffolds adequacy for 3D cell culture. To evaluate CSC enrichment, the Mammosphere Forming Index (MFI) was performed in 2D and 3D MCF7 cultures. Results showed that the 60° scaffolds were more suitable for 3D culture than the 45° and 90° ones. Moreover, 3D culture experiments, in adherent and non-adherent conditions, showed a significant increase in MFI compared to 2D cultures (control). Thus, 3D cell culture with PCL scaffolds could be useful to improve cancer cell culture and enrich the CSCs population. [ABSTRACT FROM AUTHOR]

Inexpensive piezoelectric diaphragms can be used as sensors to facilitate both nozzle height setting and build platform leveling in Fused Filament Fabrication (FFF) 3D printers. Tests simulating nozzle contact are conducted to establish the available output and an output of greater than 8 Volts found at 20 °C, a value which is readily detectable by simple electronic circuits. Tests are also conducted at a temperature of 80 °C and, despite a reduction of greater than 80% in output voltage, this is still detectable. The reliability of piezoelectric diaphragms is investigated by mechanically stressing samples over 100,000 cycles at both 20 and 80 °C, and little loss of output over the test duration is found. The development of a nozzle contact sensor using a single piezoelectric diaphragm is described.

Distributed digital manufacturing of free and open-source scientific hardware (FOSH) used for scientific experiments has been shown to in general reduce the costs of scientific hardware by 90–99%. In part due to these cost savings, the manufacturing of scientific equipment is beginning to move away from a central paradigm of purchasing proprietary equipment to one in which scientists themselves download open-source designs, fabricate components with digital manufacturing technology, and then assemble the equipment themselves. This trend introduces a need for new formal design procedures that designers can follow when targeting this scientific audience. This study provides five steps in the procedure, encompassing six design principles for the development of free and open-source hardware for scientific applications. A case study is provided for an open-source slide dryer that can be easily fabricated for under $20, which is more than 300 times less than some commercial alternatives. The bespoke design is parametric and easily adjusted for many applications. By designing using open-source principles and the proposed procedures, the outcome will be customizable, under control of the researcher, less expensive than commercial options, more maintainable, and will have many applications that benefit the user since the design documentation is open and freely accessible.

3-D printing has entered the consumer market because of recent radical price declines. Consumers can save substantial money by offsetting purchases with DIY pre-designed 3-D printed products. However, even more value can be obtained with distributed manufacturing using mass customization. Unfortunately, the average consumer is not technically sophisticated enough to easily design their own products. One solution to this is the use of an overlay on OpenSCAD parametric code, although current solutions force users to relinquish all rights to their own designs. There is thus a substantial need in the open source design community for a libre 3-D model customizer, which can be used in any design repository to democratize design. This study reports on the design, function, and validation of such software: the Free Open Source 3-D Customizer. It is demonstrated with a case study of the customization of 3-D printable external breast prosthetics. The results showed that novice users can adjust the available parameters according to their needs and save these to a new file on a website. This PHP (recursive acronym for PHP: Hypertext Preprocessor) library is free and open source and has potential for increasing the usefulness of online repositories to enable distributed manufacturing using consumer customized 3-D printable products.

RepRap Community was founded by Adrian Bowyer at the University of Bath in 2004. This initiative has promoted designs of several low cost open source 3D printers, and has proven very successful. RepRap printers’ firmware is based on 8 bits microcomputers, and an external computer is needed to process 3D models and send it to printers (by USB or SD card). We have built a RepRap variant (RepRap Azara) that doesńt need external computer, using a 32 bit ARM microcomputer (Beaglebone) and developing software and firmware able to process 3D models and to communicate through a web interface, all of it in the same costs’ range. [ABSTRACT FROM AUTHOR]

In this work, the potential of polyamide composite prepared by a 3D printer was evaluated. Polyamide 12 was compounded with 5 wt% hydroxyapatite and 15 wt% zirconium oxide fillers via a twin screw extruder. The compound was then pelletized prior to the preparation of the filament by a desktop filament extruder. The filament was finally applied to a 3D printer to prepare the printed tensile samples. Pure polyamide 12 and commercial polyamide filament, Taulman 618, were also printed and tested for control. Melt flow and thermal analysis were carried out to estimate the processing conditions. Tensile test was also conducted to evaluate the strength and modulus. The new polyamide composite was successfully prepared and tested. The strength of polyamide composite was comparable to Taulman 618. The modulus of the composite was improved due to the incorporation of fillers. The morphology of the printed composite was porous, which could provide pros and cons to biological and mechanical properties, respectively. Polyamide composite presented a promising polymer material for a 3D printer and may be applied for biomaterial application. [ABSTRACT FROM AUTHOR]

Purpose - This paper is intended to summarize the current available literature in which low-cost, open-source RepRap 3D printers are incorporated in the field of dentistry in an attempt to improve or replace conventional clinical and/or laboratory procedures. Methodology- An electronic search of publications from January 2004 to July 2014 was performed, by two researchers, in two electronic databases: Medline (PubMed) and EMBASE Library. All searches were limited to human subjects investigations, published in English. Search terms included general and specific terms from the field of dentistry and additive manufacturing. Findings - The contribution of RepRap 3D printers to the field of dentistry is so far limited to only two applications, respectively reconstruction of study models for orthodontic measurements and reconstruction of skull segments. Originality/value - This review brings focus on the few researches and applications of low-cost RepRap printers in the dental field. In spite of the promising results reported, there still remains a sizable sector in which the capabilities of these low-cost, open source 3d printers are to be tested. [ABSTRACT FROM AUTHOR]

The technological development of open source three-dimensional (3D) printers is creating more affordable Additive Manufacturing (AM) machines for society in different applications. For this reason, the machines' capability should be evaluated in order to establish minimum standards of performance. This paper deals with the development, manufacture and testing of a geometrical benchmarking model (GBM) in order to evaluate the geometrical accuracy performance of open source 3D printers. The methodology is demonstrated with a case study based on fused deposition modelling (FDM). The case study positions the evaluated machine according to ANSI-ISO's International Tolerance (IT) Grades. Furthermore, root-mean-square deviation (RMSD) value is employed as an accuracy estimator, while Taguchi tools are employed to determine the control factors with the highest accuracy for the fabrication of the GBM. [ABSTRACT FROM AUTHOR]

Highlights: [•] Open-source 3-D printers makes distributed manufacturing technically feasible. [•] Self-replicating rapid prototypers (RepRaps) can manufacture half of their own parts. [•] Life-cycle economic analysis of RepRap technology for US household provided. [•] Open-source 3-D printers recover material costs in less than 1year, >200% ROI. [•] Open-source designs growing exponentially predicts distributed manufacturing scaling. [Copyright &y& Elsevier]

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, under-developed and developing world laboratories. [ABSTRACT FROM AUTHOR]

Abstract: Additive manufacturing (AM) technologies may offer a viable and simpler alternative to fabricate scaffolds directly from patients’ data. Existing commercial AM machines are currently being modified to improve their accuracy and capabilities. However, high costs, material restrictions, and difficulty to study process parameters should be considered. In this context, this work focuses on the study and optimization of a novel open-source and low-cost 3D printer machine, called RepRap, employed to fabricate biocompatible scaffolds. Several process parameters and porosity were studied. Lastly, the RepRap printer was considered a versatile, inexpensive, flexible, and simple machine to efficiently fabricate scaffolds. [Copyright &y& Elsevier]