Rapid Manufacture of Novel Variable Impedance Robots

Variable stiffness and variable damping can play an important role in robot movement, particularly for legged robots such as bipedal walkers. Variable impedance also introduces new control problems, since there are more degrees of freedom to control, and the resulting robot has more complex dynamics. In this paper, we introduce novel design and fabrication methodologies that are capable of producing cost effective hardware prototypes suitable for investigating the efficacy of impedance modulation. We present two variable impedance bipedal platforms produced using a combination of waterjet cutting and 3D printing, and a novel fused deposition modeling (FDM) 3D printing based method for producing hybrid plastic/metal parts. We evaluate walking trajectories at different speeds and stiffness levels.

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Mechanical behavior of beams with variable stiffness obtained by 3D printing

MATEC Web of Conferences ◽

10.1051/matecconf/202134308014 ◽

2021 ◽

Vol 343 ◽

pp. 08014

Author(s):

Laszlo Racz ◽

Mircea Cristian Dudescu

Keyword(s):

3D Printing ◽

Mechanical Behavior ◽

Cross Section ◽

Process Parameters ◽

Fused Deposition Modeling ◽

Cost Effective ◽

Variable Stiffness ◽

Constant Cross Section ◽

Printing Process ◽

Fused Deposition

Additive manufacturing or 3D printing gained a widespread popularity in recent years due to the ability of the method to manufacture components with high geometrical complexity. The most cost-effective process to manufacture plastic parts using 3D printing is the fused deposition modeling (FDM) method. Process parameters as the infill rates but also the printed pattern of different layers and their orientation have a significant influence on the mechanical properties of specimens fabricated by FDM. Controlling the process parameters is possible to generate materials with variable mechanical proprieties. The paper presents the analysis of a beam with constant cross-section but variable stiffness. Variable stiffness is achieved by changes in different cross-sections of the beam of the infill rates of the printing process. The mechanical behavior consisting of force-displacements curves is analyzed by three-point bending tests of variable stiffness samples and comparison with similar beams having constant infill rate. The results consist of E-modulus variation, maximum force and deflection curve. Analytical calculations and finite element analyses are employed to predict the mechanical behavior of the specimens printed with variable infill rate. The obtained results proved the concept of equal stress-beam with constant cross-section obtained by 3D printing process parameters variation.

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Mesh-type 3D Printing of Human Organs and Tumors: Fast, Cost-Effective, and Personalized Anatomic Modeling

10.20944/preprints202012.0772.v1 ◽

2020 ◽

Author(s):

Jungirl Seok ◽

Sungmin Yoon ◽

Chang Hwan Ryu ◽

Junsun Ryu ◽

Seok-ki Kim ◽

...

Keyword(s):

3D Printing ◽

3D Modeling ◽

Fused Deposition Modeling ◽

Cost Effective ◽

Tumor Location ◽

Surgical Specimen ◽

Personalized Care ◽

Fused Deposition ◽

Mesh Work ◽

Deposition Modeling

OBJECTIVE: Although 3D-printed anatomic models are not new to medicine, the high costs and lengthy production times entailed have limited their application. Our goal was developing a new and less costly 3D modeling method to depict organ-tumor relations at faster printing speeds. METHODS: We have devised a method of 3D modeling using DICOM images. Coordinates are extracted at a specified interval, connecting them to create mesh-work replicas. Adjacent constructs are depicted by density variations, showing anatomic targets (ie, tumors) in contrasting color. RESULTS: An array of organ solid-tumor models were printed via Fused Deposition Modeling 3D printer at significantly less cost ($0.05/cm3) and time expenditure (1.73 min/cm3; both, p<.001). Printed models helped promote visual appreciation of organ-tumor anatomy and adjacent tissues. Our mesh-work 3D thyroidal prototype reproduced glangular size/contour and tumor location, readily approximating the surgical specimen. CONCLUSIONS: This newly devised mesh-type 3D printing method may facilitate anatomic modeling for personalized care and improve patient awareness during informed surgical consent.

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Dimensional Stability of 3D Printed Objects Made from Plastic Waste Using FDM: Potential Construction Applications

Buildings ◽

10.3390/buildings11110516 ◽

2021 ◽

Vol 11 (11) ◽

pp. 516

Author(s):

Essam Zaneldin ◽

Waleed Ahmed ◽

Aya Mansour ◽

Amged El Hassan

Keyword(s):

3D Printing ◽

Construction Projects ◽

Fused Deposition Modeling ◽

Three Dimensional ◽

Cost Effective ◽

Plastic Waste ◽

Fused Deposition ◽

Feasible Option ◽

3D Printers ◽

3D Printed

Construction projects are often challenged by tight budgets and limited time and resources. Contractors are, therefore, looking for ways to become competitive by improving efficiency and using cost-effective materials. Using three-dimensional (3D) printing for shaping materials to produce cost-effective construction elements is becoming a feasible option to make contractors more competitive locally and globally. The process capabilities for 3D printers and related devices have been tightened in recent years with the booming of 3D printing industries and applications. Contractors are attempting to improve production skills to satisfy firm specifications and standards, while attempting to have costs within competitive ranges. The aim of this research is to investigate and test the production process capability (Cp) of 3D printers using fused deposition modeling (FDM) to manufacture 3D printed parts made from plastic waste for use in the construction of buildings with different infill structures and internal designs to reduce cost. This was accomplished by calculating the actual requirement capabilities of the 3D printers under consideration. The production capabilities and requirements of FDM printers are first examined to develop instructions and assumptions to assist in deciphering the characteristics of the 3D printers that will be used. Possible applications in construction are then presented. As an essential outcome of this study, it was noticed that the 3D printed parts made from plastic waste using FDM printers are less expensive than using traditional lightweight non-load bearing concrete hollow masonry blocks, hourdi slab hollow bocks, and concrete face bricks.

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Extrusion-Based 3D Printing Applications of PLA Composites: A Review

Coatings ◽

10.3390/coatings11040390 ◽

2021 ◽

Vol 11 (4) ◽

pp. 390

Author(s):

Eda Hazal Tümer ◽

Husnu Yildirim Erbil

Keyword(s):

3D Printing ◽

Bone Repair ◽

Fused Deposition Modeling ◽

Water Solubility ◽

Raw Materials ◽

Three Dimensional ◽

Cost Effective ◽

Raw Material ◽

Preparation Methods ◽

Fused Deposition

Polylactic acid (PLA) is the most widely used raw material in extrusion-based three-dimensional (3D) printing (fused deposition modeling, FDM approach) in many areas since it is biodegradable and environmentally friendly, however its utilization is limited due to some of its disadvantages such as mechanical weakness, water solubility rate, etc. FDM is a simple and more cost-effective fabrication process compared to other 3D printing techniques. Unfortunately, there are deficiencies of the FDM approach, such as mechanical weakness of the FDM parts compared to the parts produced by the conventional injection and compression molding methods. Preparation of PLA composites with suitable additives is the most useful technique to improve the properties of the 3D-printed PLA parts obtained by the FDM method. In the last decade, newly developed PLA composites find large usage areas both in academic and industrial circles. This review focuses on the chemistry and properties of pure PLA and also the preparation methods of the PLA composites which will be used as a raw material in 3D printers. The main drawbacks of the pure PLA filaments and the necessity for the preparation of PLA composites which will be employed in the FDM-based 3D printing applications is also discussed in the first part. The current methods to obtain PLA composites as raw materials to be used as filaments in the extrusion-based 3D printing are given in the second part. The applications of the novel PLA composites by utilizing the FDM-based 3D printing technology in the fields of biomedical, tissue engineering, human bone repair, antibacterial, bioprinting, electrical conductivity, electromagnetic, sensor, battery, automotive, aviation, four-dimensional (4D) printing, smart textile, environmental, and luminescence applications are presented and critically discussed in the third part of this review.

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Towards an ultra-affordable 3D bioprinter: A Heated Inductive-Enabled Syringe Pump Extrusion (HISPE) multifunction module for open-source FDM 3D printers

Journal of Manufacturing Science and Engineering ◽

10.1115/1.4050824 ◽

2021 ◽

pp. 1-31

Author(s):

Lamis R. Darwish ◽

Mohamed T. El-Wakad ◽

Mahmoud Farag

Keyword(s):

3D Printing ◽

Open Source ◽

Fused Deposition Modeling ◽

Cost Effective ◽

3D Printer ◽

Syringe Pump ◽

Fused Deposition ◽

Filament Diameter ◽

3D Printers ◽

Deposition Modeling

Abstract The extrusion systems of the widespread Fused Deposition Modeling (FDM) 3D printers enable printing only with materials in the filament form. This property hinders the usage of these FDM 3D printers in many fields where the printing materials are in forms other than filaments. Thus, this paper proposes a Heated Inductive-enabled Syringe Pump Extrusion (HISPE) multifunction open-source module with a potential application in bioprinting (i.e., extrusion-based bioprinting). The proposed HISPE module is designed to be cost-effective, simple, and easy to replicate. It is capable of replacing the conventional extrusion system of any open-source cartesian FDM 3D printer. This module widens both the range of the FDM 3D printing materials (e.g., bioinks, biopolymers, blends of materials, or composites) and their forms (e.g., hydrogels, powder, pellets, or flakes). The capabilities of the proposed module were investigated through 3D printing bone scaffolds with a filament diameter of 400 µm and pore size of 350 µm by a Polycaprolactone (PCL) biodegradable polymer in the pellets form. The morphological accuracy of the printed scaffolds was investigated by SEM. The investigation results confirm the accurateness of the proposed HISPE module in printing high-precision models.

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Process Based Modeling of Energy Consumption for Multi-material FDM 3D Printing

10.21203/rs.3.rs-44077/v1 ◽

2020 ◽

Author(s):

Yu Liu ◽

Jinghua Chen ◽

Erwei Shang ◽

Yanqiu Chen

Keyword(s):

Energy Consumption ◽

3D Printing ◽

Fused Deposition Modeling ◽

Cost Effective ◽

Fused Deposition ◽

Energy Consumption Analysis ◽

Deposition Modeling ◽

Nozzle Temperature ◽

Demand Changes ◽

3D Printing Technique

Abstract Fused deposition modeling (FDM) is one most cost-effective 3D printing technique for forming complex 3D components based on thermoplastic materials. The energy consumption analysis is one criterion to determine the capacity and sustainability of the FDM. In this paper, the energy consumption of a dual- extruder FDM is studied by differentiating the whole multi-material printing process into independent operation modes, which characterize the thermal behaviors of the printing parameters. By investigating the execution instruction which describe the tooling plan of the FDM, the nozzle temperature distributions with different filament materials are measured and simulated. The energy consumption details can be accurately captured in our work and therefore we are able to predicate the power demand changes with different working processes of the multi-material FDM 3D printing. This work will be beneficial for optimization of 3D printer design and manufacturing sustainability in next.

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Biodegradable 3D Printed Polymer Microneedles for Transdermal Drug Delivery

10.26434/chemrxiv.5851950.v1 ◽

2018 ◽

Cited By ~ 1

Author(s):

Michael A. Luzuriaga ◽

Danielle R. Berry ◽

John C. Reagan ◽

Ronald A. Smaldone ◽

Jeremiah J. Gassensmith

Keyword(s):

Drug Delivery ◽

3D Printing ◽

Transdermal Drug Delivery ◽

Fused Deposition Modeling ◽

Fused Deposition ◽

Modeling Software ◽

Deposition Modeling ◽

3D Printed ◽

Microfabrication Technique ◽

Mechanical Strengths

Biodegradable polymer microneedle (MN) arrays are an emerging class of transdermal drug delivery devices that promise a painless and sanitary alternative to syringes; however, prototyping bespoke needle architectures is expensive and requires production of new master templates. Here, we present a new microfabrication technique for MNs using fused deposition modeling (FDM) 3D printing using polylactic acid, an FDA approved, renewable, biodegradable, thermoplastic material. We show how this natural degradability can be exploited to overcome a key challenge of FDM 3D printing, in particular the low resolution of these printers. We improved the feature size of the printed parts significantly by developing a post fabrication chemical etching protocol, which allowed us to access tip sizes as small as 1 μm. With 3D modeling software, various MN shapes were designed and printed rapidly with custom needle density, length, and shape. Scanning electron microscopy confirmed that our method resulted in needle tip sizes in the range of 1 – 55 µm, which could successfully penetrate and break off into porcine skin. We have also shown that these MNs have comparable mechanical strengths to currently fabricated MNs and we further demonstrated how the swellability of PLA can be exploited to load small molecule drugs and how its degradability in skin can release those small molecules over time.

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3D Printing of Mini Tablets for Pediatric Use

Pharmaceuticals ◽

10.3390/ph14020143 ◽

2021 ◽

Vol 14 (2) ◽

pp. 143

Author(s):

Julius Krause ◽

Laura Müller ◽

Dorota Sarwinska ◽

Anne Seidlitz ◽

Malgorzata Sznitowska ◽

...

Keyword(s):

3D Printing ◽

Fused Deposition Modeling ◽

Dosage Forms ◽

Small Scale ◽

Fused Deposition ◽

On Demand ◽

Pediatric Diseases ◽

Deposition Modeling ◽

Manufacturing Techniques ◽

Pediatric Use

In the treatment of pediatric diseases, suitable dosages and dosage forms are often not available for an adequate therapy. The use of innovative additive manufacturing techniques offers the possibility of producing pediatric dosage forms. In this study, the production of mini tablets using fused deposition modeling (FDM)-based 3D printing was investigated. Two pediatric drugs, caffeine and propranolol hydrochloride, were successfully processed into filaments using hyprolose and hypromellose as polymers. Subsequently, mini tablets with diameters between 1.5 and 4.0 mm were printed and characterized using optical and thermal analysis methods. By varying the number of mini tablets applied and by varying the diameter, we were able to achieve different release behaviors. This work highlights the potential value of FDM 3D printing for the on-demand production of patient individualized, small-scale batches of pediatric dosage forms.

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Mechanical Characterization and Thermodynamic Analysis of Laser-Polished Landscape Design Products Using 3D Printing

Materials ◽

10.3390/ma14102601 ◽

2021 ◽

Vol 14 (10) ◽

pp. 2601

Author(s):

Yue Ba ◽

Yu Wen ◽

Shibin Wu

Keyword(s):

Surface Roughness ◽

3D Printing ◽

Fused Deposition Modeling ◽

High Surface ◽

Landscape Design ◽

Laser Polishing ◽

Fused Deposition ◽

Design Structure ◽

3D Printed ◽

Stability And Accuracy

Recent innovations in 3D printing technologies and processes have influenced how landscape products are designed, built, and developed. In landscape architecture, reduced-size models are 3D-printed to replicate full-size structures. However, high surface roughness usually occurs on the surfaces of such 3D-printed components, which requires additional post-treatment. In this work, we develop a new type of landscape design structure based on the fused deposition modeling (FDM) technique and present a laser polishing method for FDM-fabricated polylactic acid (PLA) mechanical components, whereby the surface roughness of the laser-polished surfaces is reduced from over Ra 15 µm to less than 0.25 µm. The detailed results of thermodynamics and microstructure evolution are further analyzed during laser polishing. The stability and accuracy of the results are evaluated based on the standard deviation. Additionally, the superior tensile and flexural properties are examined in the laser-polished layer, in which the ultimate tensile strength (UTS) is increased by up to 46.6% and the flexural strength is increased by up to 74.5% compared with the as-fabricated components. Finally, a real polished landscape model is simulated and optimized using a series of scales.

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