Low-cost 3D Printer Research Articles

Embedded 3D Printing of PDMS-Based Microfluidic Chips for Biomedical Applications

Abstract Microfluidic devices made from polydimethylsiloxane (PDMS) have diverse biomedical applications. However, due to the poor printability of PDMS, current 3D printing techniques are rarely used to fabricate microfluidic devices. This study aims to investigate a fumed silica-PDMS suspension that can function as a matrix bath for embedded 3D printing (e-3DP) purposes, making it technically feasible to print microfluidic chips with complex embedded channels via low-cost extrusion 3D printing. The rheological properties, mechanical properties, transparency, and filament fidelity of the fumed silica-PDMS suspension have been systematically studied. It is found that the addition of fumed silica particles can effectively change PDMS from a viscous solution to a yield-stress suspension with suitable rheological properties for e-3DP. Also, the mechanical properties of the crosslinked fumed silica-PDMS are enhanced with an increased concentration of fumed silica. Although the transparency of PDMS has been lessened by mixing it with fumed silica particles, the visibility of the printed microfluidic chips is still acceptable. The filament fidelity has been studied by embedded printing filaments using a sacrificial ink in the fumed silica-PDMS suspension. Finally, two representative microfluidic chips for biomedical applications have been successfully printed to validate the effectiveness of the proposed fumed silica-PDMS suspension-enabled e-3DP method.

Thermal Post-Processing of 3D Printed Polypropylene Parts for Vacuum Systems

Access to vacuum systems is limited because of economic costs. A rapidly growing approach to reduce the costs of scientific equipment is to combine open-source hardware methods with digital distributed manufacturing with 3D printers. Although high-end 3D printers can manufacture vacuum components, again, the cost of access to tooling is economically prohibitive. Low-cost material extrusion 3D printing with plastic overcomes the cost issue, but two problems arise when attempting to use plastic in or as part of vacuum systems: the outgassing of polymers and their sealing. To overcome these challenges, this study explores the potential of using post-processing heat treatments to seal 3D printed polypropylene for use in vacuum environments. The effect of infill overlap and heat treatment with a readily available heat gun on 3D printed PP parts was investigated in detail on ISO-standardized KF vacuum fitting parts and with the use of computer vision-based monitoring of vacuum pump down velocities. The results showed that infill overlap and heat treatment both had a large impact on the vacuum pressures obtainable with 3D printed parts. Heat treatment combined with 98% infill reliably sealed parts for use in vacuum systems, which makes the use of low-cost desktop 3D printers viable for manufacturing vacuum components for open scientific hardware.

Low‐Cost Volumetric 3D Printing of High‐Precision Miniature Lenses in Seconds (Advanced Optical Materials 17/2022)

Targeting the fast prototyping and massive production of complicated lenses, Zhiwei Zhu and co-workers report a low-cost volumetric 3D printing method for the ultra-fast and high-precision fabrication of miniature lenses with sub-nanometric roughness (see article number 2200488). The complex-shaped lenses are generated by the volumetric projection stereolithography and corrected by introducing an iterative learning scheme. Super-smooth surfaces are guaranteed by the meniscus equilibrium effect.

Low-cost and low-temperature 3D printing for refractory composite inspired by fused deposition modeling and binder jetting

Inspired by two subsets of additive manufacturing, a novel method of low-cost and low-temperature 3D printing for net shape refractory products has been proposed and validated in the present work. Taking the typical refractory composite of tungsten-copper as an instance, the feedstock for printing was made of 97 wt% W-Cu composite powders and 3 wt% binder. The resulted W-Cu composite was printed on a desktop 3D printer at room temperature, followed by designated degreasing and hydrogen-reduction sintering. Characteristics including phase constituents, microstructure, mechanical and electrical properties of the resulted composite have been identified. The revealed neat and intact interfaces between the constituent Cu and W after fully degreasing ensured sufficient loading transfer and deformation coordination, contributing to excellent mechanical properties with high electrical conductivity. This work extended the feasibility of fabricating refractory alloys without molds and expensive equipment, providing a new solution and scheme for refractory materials with intricate structures.

Linking Processing Parameters and Rheology to Optimize Additive Manufacturing of k-Carrageenan Gel Systems.

Additive manufacturing—in particular, three-dimensional (3D) printing—has been introduced since the late 1980s, offering a novel paradigm for engineering design and manufacturing, as it allows the fabrication of very complex structures. Additive manufacturing of hydrogels is a very popular method to produce scaffolds to be used in tissue engineering and other biomedical applications, as well as in other advanced technological areas. When printing a thermoreversible physical hydrogel, a subtle balance between thermal and rheological parameters exists. The characteristic times of the sol–gel transition, regulated by a well-defined thermal history, must be optimized with respect to the characteristic processing times. In this work, we use this thermo-rheological approach to the additive manufacturing of a physical hydrogel. A low-cost desktop 3D printer for thermoplastic polymers was suitably modified to print a 1.5 wt% solution of k-carrageenan. The thermal behavior of the printer was determined by performing experimental measurements of the temperature–time evolution during the different processing steps, from solution loading, to the extrusion of the incoming gel, to the final solidification stage. In parallel, linear viscoelastic oscillatory shear measurements were performed in a rotational rheometer under thermal histories as close as possible to those previously measured in the printing process. The comparison between the rheological results and the quality of printing under different thermal histories is presented and discussed, highlighting the main relations between rheological and processing behavior, which are helpful in the assessment and optimization of the printing conditions.

Designing Cost-Effective Open-Source Multihead 3D Bioprinters.

For the past decade, additive manufacturing has resulted in significant advances toward fabricating anatomic-size patient-specific scaffolds for tissue models and regenerative medicine. This can be attributed to the development of advanced bioinks capable of precise deposition of cells and biomaterials. The combination of additive manufacturing with advanced bioinks is enabling researchers to fabricate intricate tissue scaffolds that recreate the complex spatial distributions of cells and bioactive cues found in the human body. However, the expansion of this promising technique has been hampered by the high cost of commercially available bioprinters and proprietary software. In contrast, conventional three-dimensional (3D) printing has become increasingly popular with home hobbyists and caused an explosion of both low-cost thermoplastic 3D printers and open-source software to control the printer. In this study, we bring these benefits into the field of bioprinting by converting widely available and cost-effective 3D printers into fully functional, open-source, and customizable multihead bioprinters. These bioprinters utilize computer controlled volumetric extrusion, allowing bioinks with a wide range of flow properties to be bioprinted, including non-Newtonian bioinks. We demonstrate the practicality of this approach by designing bioprinters customized with multiple extruders, automatic bed leveling, and temperature controls for ∼$400 USD. These bioprinters were then used for in vitro and ex vivo bioprinting to demonstrate their utility for tissue engineering.

Highly sensitive and flexible three-dimensional force tactile sensor based on inverted pyramidal structure

To improve the haptic sensing performance of electronic skin (e-skin), this study designed a capacitance-based highly sensitive three-dimensional (3D) force tactile sensor with an inverted pyramidal structure with high electrical stability and mechanical repeatability. The working mechanism of the sensor was verified by finite element simulation, and it was fabricated by low-cost 3D printing technology and layer-by-layer self-assembly process. A capacitive signal acquisition system and an application test platform were constructed. The results revealed that the proposed 3D-force tactile sensor had a normal force sensitivity of 0.551 N−1 at 0–7 N and 0.107 N−1 at 7–35 N. The results for tangential force were 0.404 N−1 at 0–4 N and 0.227 N−1 at 4–14 N, with a low hysteresis of 4.17% and a fast response/recovery time of 56/30 ms. High sensitivity and reliability of the device were demonstrated experimentally. The proposed capacitive flexible 3D-force haptic sensor can be used in applications such as robotic gripping, gamepad control and human motion detection, and its feasibility for application as e-skin was confirmed.

Roughness investigation of steel 316L parts fabricated by Metal Fused Filament Fabrication

Metal Fused Filament Fabrication attracted significant interest in both academia and industry to fabricate net-shape engineering components via low-cost 3D printing technology. However, many fields such as the roughness control and prediction are still unexplored. These aspects are very important to consider especially when the process is used for the fabrication of functional parts: the roughness, in fact, deeply influences the functionality of a component in terms of friction, contact deformation, heat, electric current conduction, etc. Aim of this work is to fulfill the lack of knowledge about the prediction of the obtainable roughness in this process. For the purpose an in-depth analysis of the effect of the processing parameters on surface roughness profiles obtained at green and sintered stages is reported. The experiment is planned using the Design of Experiments technique and the data are collected followed a rigid procedure developed for the scope. The results show that the profiles are markedly affected by the process parameters and depend upon the deposition angles. Green and sintered parts show different behaviors caused by different underling mechanisms. The complexity of the process is highlighted and described by regression models for different deposition angles. The models set allows for a multiple optimization in order to achieve processing parameters combinations able to satisfy desired requirements.

Leveraging physical intelligence for the self-design of high performance engineering structures

The design of complex engineering structures largely relies on computational intelligence in the form of science-based predictive models to support design decisions. This approach requires modeling and manufacturing uncertainties to be accounted for explicitly and leads to an inescapable trade-off of performance for robustness. To remedy this situation, a novel self-design paradigm is proposed that closes the loop between the design and manufacturing processes by leveraging physical intelligence in the form of real-time experimental observations. This allows the real-time product behavior to participate in its own design. The main benefit of the proposed paradigm is that both manufacturing variability and difficult-to-model physics are accounted for implicitly via in situ measurements thus circumventing the performance-robustness trade-off and guaranteeing enhanced performance with respect to standardized designs. This paradigm shift leads to tailored design realizations which could benefit a wide range of high performance engineering applications. The proposed paradigm is applied to the design of a simply-supported plate with a beam-like absorber introduced to reduce vibrations based on an equal peaks performance criteria. The experimental setup includes a low-cost 3D printer driven by a simple decision algorithm and equipped with an online vibration testing system. The performances of a small population of self-designed plates are compared to their standardized counterparts in order to highlight the advantages and limitations of the new self-design manufacturing paradigm.

Design and Manufacturing of Feeding System to Improve Accuracy and Surface Roughness of FDM Products

Fused Deposition Modeling, a great potential technology, has been increasingly applied in various industries as rapid prototyping for testing, casting prototyping and final products manufacturing. This widely usage comes with high products accuracy requirements. Currently, industrial 3D printers are very high in price that open-source low cost printers are the most suitable for hobbyist and researchers in the world. Therefore, research to improve product quality for low-cost 3D printers to serve industrial demand is greatly necessary. Realizing that in FDM technology, the feeding method is one of the important issues that determine the accuracy of printed products. The problem to be studied here is to design and manufacture a filament feeding system for a low-cost 3D printer and find out an optimal set of parameters for the fabricated feeder. This paper analyzes the feeding systems for 3D printers that have been used on the market, thereby offering a design and manufacturing feeder for the low-cost 3D printer. Then, experiments with Polylactic Acid (PLA) filament will be taken to check the accuracy of printed products and figure out the optimal set of technological parameters for the 3D printing process. Thereby improving product quality and shortening printing time. Continue to research and perfect the design can help commercialize low-cost 3D printers and stimulate research as well as 3D printing in industries.

Patient-specific brain arteries molded as a flexible phantom model using 3D printed water-soluble resin

Visualizing medical images from patients as physical 3D models (phantom models) have many roles in the medical field, from education to preclinical preparation and clinical research. However, current phantom models are generally generic, expensive, and time-consuming to fabricate. Thus, there is a need for a cost- and time-efficient pipeline from medical imaging to patient-specific phantom models. In this work, we present a method for creating complex 3D sacrificial molds using an off-the-shelf water-soluble resin and a low-cost desktop 3D printer. This enables us to recreate parts of the cerebral arterial tree as a full-scale phantom model (10times 6times 4 cm) in transparent silicone rubber (polydimethylsiloxane, PDMS) from computed tomography angiography images (CTA). We analyzed the model with magnetic resonance imaging (MRI) and compared it with the patient data. The results show good agreement and smooth surfaces for the arteries. We also evaluate our method by looking at its capability to reproduce 1 mm channels and sharp corners. We found that round shapes are well reproduced, whereas sharp features show some divergence. Our method can fabricate a patient-specific phantom model with less than 2 h of total labor time and at a low fabrication cost.

3D Printed Face Shield

Abstract: In the fourth industrial revolution, a sort of printing technology that has the potential to transform the manufacturing industry is 3D printing. It takes just a few hours to develop a new product with this technology which might take days and months with traditional technologies. This research highlights a low-cost 3D printer’s design and its working. The whole printer was developed to make it less expensive than similar products already on the market. The results show that low-cost printers with good accuracy can be designed. Keywords: 3D printing, Face shield, CAD Software, stereo lithography, fused deposition manufacturing

Development and characterization of sustainable PLA/Olive wood waste composites for rehabilitation applications using Fused Filament Fabrication (FFF)

An understanding of how the construction industry can support the transition towards a Circular Economy (CE) of the built environment plays a key role in rehabilitation processes that often require skilled labor.Fused Filament Fabrication (FFF), an Additive Manufacturing (AM) technique, is a new technology recently proposed for this purpose. In recent years, a number of studies have been presented to improve the sustainability of the main materials used in 3D printing (e.g. PLA filament), suggesting, in particular, some interesting composite filaments.The present paper is related to the development and characterization of sustainable materials, able to reduce the environmental impacts of the conventional materials for FFF. More specifically, various composite filaments based on polylactic acid (PLA) and different amounts of olive wood scraps were produced by an extrusion process and fully characterized from a physical, thermal and mechanical point of view. As they are suitable for application in a low-cost 3D printing machine, these filaments are used to build simple 3D printed models as a first exploitation of architectural building elements based on wood powder.In addition, in order to evaluate the environmental advantages of the wood waste derived composite filaments, the impact indicators were also quantified by Life Cycle Assessment (LCA). LCA results showed environmental benefits resulting from the inclusion of wood scraps in PLA filaments (20% of wood corresponds to 10% impact reduction) supporting further research in this area.

A simple and scalable 3D printing methodology for generating aligned and extended human and murine skeletal muscle tissues

Preclinical biomedical and pharmaceutical research on disease causes, drug targets, and side effects increasingly relies on in vitro models of human tissue. 3D printing offers unique opportunities for generating models of superior physiological accuracy, as well as for automating their fabrication. Towards these goals, we here describe a simple and scalable methodology for generating physiologically relevant models of skeletal muscle. Our approach relies on dual-material micro-extrusion of two types of gelatin hydrogel into patterned soft substrates with locally alternating stiffness. We identify minimally complex patterns capable of guiding the large-scale self-assembly of aligned, extended, and contractile human and murine skeletal myotubes. Interestingly, we find high-resolution patterning is not required, as even patterns with feature sizes of several hundred micrometers is sufficient. Consequently, the procedure is rapid and compatible with any low-cost extrusion-based 3D printer. The generated myotubes easily span several millimeters, and various myotube patterns can be generated in a predictable and reproducible manner. The compliant nature and adjustable thickness of the hydrogel substrates, serves to enable extended culture of contractile myotubes. The method is further readily compatible with standard cell-culturing platforms as well as commercially available electrodes for electrically induced exercise and monitoring of the myotubes.

Automated Design and Rapid Manufacturing of Low-Cost Customized Upper Limb Prostheses

The paper presents results of studies on an innovative approach to mass customization of prostheses, namely automated design and rapid manufacturing (3D printing), on the basis of 3D scanning of upper limb of a given patient. Two different products are presented – a simple mechanical prosthesis and a cosmetic prosthesis. In both cases, intelligent CAD models, with adaptive geometry – changing automatically to the data from 3D scanning – were prepared. The digital models were built and tested using data of real patients. A special algorithm of 3D scanning data processing was prepared and implemented, as well as a set of algorithms of automated data processing for 3D printing processes. The test models were manufactured using low-cost 3D printing technology. The verification was successful – possibility of preparing customized prostheses was reached, using automated design.

Fabrication of a highly protective 3D-printed mask and evaluation of its viral filtration efficiency using a human head mannequin

Facemasks are one of the most effective and low-cost prophylactics for COVID-19. In the spring 2020, when a severe shortage of facemasks occurred worldwide, various types of 3D-printed masks were designed and proposed. However, the protective effects conferred by most of these masks were not experimentally evaluated. Here, we provide a new simple design of 3D-printed mask and evaluate its protective effect in a viral filtration test using a human head mannequin. The developed mask can be constructed with a low-cost 3D printer, with an approximate production cost of US $4. This mask has three parts: the main part, wearing parts, and a piece of non-woven fabric filter. The volume of the filter, which needs to be changed daily, was reduced to approximately 1/10 of that of commercially available surgical masks used in this study. The developed mask is fabricated from polylactic acid, a biodegradable plastic, and its surface contour contacting the face may be adjusted after softening the material with hot water at 60–80 °C. The viral filtration efficiency of the developed mask was found to be over 80%. This performance is better than that of commercially available facemasks, such as surgical masks and cloth masks, and equal to those of KN95 and KF94.

Computational design synthesis for Fabrication-Aware assembly problems using building objects with dimensional variations

State-of-the-art computational design approaches for designing the assembly of a structure often rely on high-precision building objects, which can be difficult and costly to fabricate. To consider a wider range of construction materials and fabrication processes, e.g. low-cost 3D printing and brick making, this research introduces a novel computational design method for fabrication-aware assembly problems using existing building components with dimensional variations. Given a finite set of building objects, this study develops a statistical preprocessing approach and a modified pattern search with an efficient integer linear programming method to generate the assembly of a target structure, such that it is statically stable and optimized for geometric smoothness and space utilization. In two case studies, the proposed algorithm exhibits significantly better boundary fitting and space utilization compared with a genetic algorithm and a standard pattern search method and lower computational cost compared with a genetic algorithm.

Low cost 3D printing of metals using filled polymer pellets

Nowadays, additive manufacturing of metallic materials is most often carried out using expensive and complex tools that leave the user with limited control and no possibility of modification. In order to make the printing of metal parts more accessible to small structures but also better suited for academic research, the use of a mixture of thermoplastic polymer and metal powder is a good solution as many granular feedstocks already exist for Metal Injection Molding applications. To perform the shaping process, the Fused Granular Fabrication 3D printing technology is set up by diverting the use of a feedstock in the form of pellets that are directly inserted into the print head. This solution, which is less costly, is implemented here by modifying a mid-range printer, the Tool Changer from E3D, and by making the hardware and software adaptations to mount a compact granulates extruder on it, which is also available on the market. The polymer portion present in the green part can then be removed in order to perform the heat treatments that will densify the powder by sintering and give a fully metallic dense object.

Cost-effective wideband dielectric planar lens antenna for millimeter wave applications

This article presents a fully 3D-printed dielectric planar lens operating in the entire Ka-band manufactured using additive manufacturing and a relatively low-cost 3D-printer. The lens consists of ten concentric rings implemented using low-loss ABS filaments with high permittivity values. By varying the infill percentages of them the required refractive indexes of each section are achieved. An additional 3D-printed matching layer, using the same manufacturing and design method was included in the lens, to reduce reflections. Simulation and measurement results show a very good agreement, which confirms the possibility of manufacturing a cost-effective broadband and planar lens solution operating in millimeter wave bands, where Low Earth Orbit Satellites (LEO) networks, future mobile communication systems (5G, 6G) and radar systems operate.

Enabling consumer-grade 3D-printed optical instruments – a case study on design and fabrication of a spectrometer system using low-cost 3D printing technologies

3D printing of optical components can broaden access to optical fabrication. However, consumer options for 3D printing have been limited due to the form and roughness requirements for optics. Previous efforts have established a protocol for the fabrication of singlet lenses using a stereolithographic printer and simple post-processing techniques. Here we further elevate this research by building a consumer-grade 3D printed spectrometer utilizing achromatic doublet printed lenses. These lenses are fabricated using stereolithographic printers with a filled cavity and reduce chromatic focal shift by a factor of 6 over singlet lenses. The proof-of-concept spectrometer system incorporates a pinhole, two doublet lenses, and a dispersing prism. Opto-mechanics for the system were fabricated using an FDM 3D printer. Results from the fabricated system closely matched results obtained with a commercially available spectrometer device.