Modelling the stiffness of plastic springs manufactured via additive manufacturing

2021 ◽  
pp. 095440542110382
Author(s):  
Enea Sacco ◽  
Seung Ki Moon
Keyword(s):  
Additive Manufacturing ◽  
3D Printing ◽  
Cross Section ◽  
Radiation Resistance ◽  
Orthotropic Material ◽  
Helical Spring ◽  
Design And Manufacturing ◽  
Wire Cross Section ◽  
3D Printed

The helical spring is one of the most used components in mechanisms but there is little research on the application of 3D printing, also called Additive Manufacturing, to springs. Therefore, the objective of this paper is to derive a model for the stiffness of 3D printed springs. The equation assumes that springs are made of orthotropic material and with a rectangular wire cross-section, that is, die springs. A second version of the equation has also been postulated that accounts for the misalignment of the deposited tracks with respect to the direction of the coils due to the coil pitch. The two models are compared to various springs printed with PLA and ULTEM 9085 and are found to accurately predict the stiffness of real, 3D printed springs. These equations allow the design and manufacturing of helical die springs for applications with few load cycles and that require chemical and radiation resistance, such as in space. The equations are also the first step in the development of models for new kinds of springs, such as linear conical springs or hollow wire die springs.

Design and Manufacturing of a Metal 3D Printed kW Scale Axial Turboexpander

2019 ◽  
Author(s):  
Vaclav Novotny ◽  
Monika Vitvarova ◽  
Michal Kolovratnik ◽  
Barbora Bryksi Stunova ◽  
Vaclav Vodicka ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
3D Printing ◽  
Surface Quality ◽  
High Efficiency ◽  
Cost Effective ◽  
Manufacturing Cost ◽  
Machining Processes ◽  
Manufacturing Method ◽  
Design And Manufacturing ◽  
3D Printed

Abstract Greater expansion of distributed power and process systems based on thermodynamic cycles with single to hundred kW scale power output is limited mainly there are not available cost-effective expanders. Turboexpanders have a perspective of high efficiency and flexibility concerning operating parameters even for the micro applications. However, they suffer from a high manufacturing cost and lead time in the development of traditional technologies (such as casting and machining processes). Additive manufacturing provides a possibility to overcome some of the issues. Manufacturing parts with complicated shapes by this technology, combining multiple components into a single part or rapid production by 3D printing for development purposes are among the prospective features with this potential. On the other hand, the 3D printing processes come with certain limitations which need to be overcome. This paper shows a design and manufacturing process of a 3 kW axial impulse air turbine working with isenthalpic drop 30 kJ/kg. Several samples to verify printing options and the turbine itself has been manufactured from stainless steel by the DMLS additive manufacturing method. Manufactured are two turbine variations regarding blade size and 3D printer settings while maintaining their specific dimensions. The turboexpanders testing method and rig is outlined. As the surface quality is an issue, several methods of post-processing of 3D printed stator and rotor blading to modify surface quality are suggested. Detailed experimental investigation is however subject of future work.

Generation and Investigation of Embedded Micro-Channels Network Using Three Dimensional Printing Technology

2017 ◽  
Author(s):  
Austin Smith ◽  
Hamzeh Bardaweel
Keyword(s):  
Additive Manufacturing ◽  
3D Printing ◽  
Cross Section ◽  
Rectangular Cross Section ◽  
Hydrodynamic Characteristics ◽  
Shear Stresses ◽  
Printing Technology ◽  
Micro Channels ◽  
3D Printed ◽  
Printing Direction

The work presented here is motivated by the recent growing interest in using additive manufacturing to fabricate micro-channels networks. Distorted shapes and rough geometries influence hydrodynamic characteristics of micro-channels by increasing their flow resistance and pressure drop or altering wall shear stresses inside them. Since geometric conformity and shape fidelity of micro-channels networks are greatly influenced by manufacturing process, this work is focused on dimensional characterization of micro-channels fabricated using additive manufacturing. In this work, circular and rectangular cross-section micro-channels are 3D printed. Shapes and dimensions of 3D printed micro-channels are examined using Scanning Electron Microscope (SEM) imaging. In this work, 500 μm diameter and 200 μm square transparent PolyLactic Acid (PLA) micro-channels are 3D printed with average errors 0.25% and 1.65%, respectively. SEM images confirmed geometric conformity and shape fidelity of the 3D printed circular and rectangular cross-section micro-channels. Statistical analysis is performed on multiple prints to verify reproducibility and shape conformity. Results show that factors such as printing direction play essential role in the shape conformity and geometric fidelity of the micro-channels. Although 3D printing is a promising route for attaining micro-channels there are still significant improvements that can be made to the precision of the printer in the XY plane for printing small geometric figures. This improvement will likely come as the printing technology and software both improve to allow the operator more control over the outcome of the print. Additionally, new 3D printing materials may open the gate for new applications in different fields such as thermal management and microfluidics.

Fused Filament Fabrication 3D Printed Polylactic Acid Electroosmotic Pumps

Lab on a Chip ◽  
2021 ◽  
Author(s):  
Liang Wu ◽  
Stephen Beirne ◽  
Joan-Marc Cabot Canyelles ◽  
Brett Paull ◽  
Gordon G. Wallace ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
3D Printing ◽  
Polylactic Acid ◽  
Fused Filament Fabrication ◽  
Flexible Approach ◽  
Electroosmotic Pump ◽  
3D Printed ◽  
Electroosmotic Pumps

Additive manufacturing (3D printing) offers a flexible approach for the production of bespoke microfluidic structures such as the electroosmotic pump. Here a readily accessible fused filament fabrication (FFF) 3D printing...

Algorithm to Reduce Leading and Lagging in Conformal Direct-Print

2018 ◽  
Vol 140 (10) ◽  
Author(s):  
Morteza Vatani ◽  
Faez Alkadi ◽  
Jae-Won Choi
Keyword(s):  
Additive Manufacturing ◽  
3D Printing ◽  
3D Model ◽  
Three Dimensional ◽  
Motion Direction ◽  
B Spline ◽  
And Topology ◽  
Printing System ◽  
3D Printed ◽  
Printed Patterns

A novel additive manufacturing algorithm was developed to increase the consistency of three-dimensional (3D) printed curvilinear or conformal patterns on freeform surfaces. The algorithm dynamically and locally compensates the nozzle location with respect to the pattern geometry, motion direction, and topology of the substrate to minimize lagging or leading during conformal printing. The printing algorithm was implemented in an existing 3D printing system that consists of an extrusion-based dispensing module and an XYZ-stage. A dispensing head is fixed on a Z-axis and moves vertically, while the substrate is installed on an XY-stage and moves in the x–y plane. The printing algorithm approximates the printed pattern using nonuniform rational B-spline (NURBS) curves translated directly from a 3D model. Results showed that the proposed printing algorithm increases the consistency in the width of the printed patterns. It is envisioned that the proposed algorithm can facilitate nonplanar 3D printing using common and commercially available Cartesian-type 3D printing systems.

Hybrid Polymer Additive Manufacturing of a Darrieus Type Vertical Axis Wind Turbine Design to Improve Power Generation Efficiency

2016 ◽  
Author(s):  
Sourabh Deshpande ◽  
Nithin Rao ◽  
Nitin Pradhan ◽  
John L. Irwin
Keyword(s):  
Power Generation ◽  
Additive Manufacturing ◽  
3D Printing ◽  
Wind Turbine ◽  
Turbine Blades ◽  
Vertical Axis ◽  
Blade Design ◽  
Vertical Axis Wind Turbine ◽  
Wind Turbine Blades ◽  
3D Printed

Utilizing the advantages of additive manufacturing methods, redesigning, building and testing of an existing integral Savonius / Darrieus “Lenz2 Wing” style vertical axis wind turbine is predicted to improve power generation efficiency. The current wind turbine blades and supports made from aluminum plate and sheet are limiting the power generation due to the overall weight. The new design is predicted to increase power generation when compared to the current design due to the lightweight spiral Darrieus shaped hollow blade made possible by 3D printing, along with an internal Savonius blade made from aluminum sheet and traditional manufacturing techniques. The design constraints include 3D printing the turbine blades in a 0.4 × 0.4 × 0.3 m work envelope while using a Stratasys Fortus 400mc and thus the wind turbine blades are split into multiple parts with dovetail joint features, when bonded together result in a 1.2 m tall working prototype. Appropriate allowance in the mating dovetail joints are considered to facilitate the fit and bonding, as well as angle, size and placement of the dovetail to maximize strength. The spiral shape and Darrieus style cross section of the blade that provides the required lift enabling it to rotate from the static condition are oriented laterally for 3D printing to maximize strength. The bonding of the dovetail joints is carried out effectively using an acetone solution dip. The auxiliary components of the wind turbine which include the center support pole, top and bottom support, and center Savonius blades are manufactured using lightweight aluminum. Design features are included in the 3D printed blade parts so that they can be assembled with the aluminum parts in bolted connections. Analysis of the 3D CAD models show that the hybrid aluminum and hollow 3D printed blade construction provides a 50% cost savings over a 3D printed fully solid blade design while minimizing weight and maximizing the strength where necessary. Analysis of the redesign includes a detailed weight comparison, structural strength and the cost of production. Results include linear static finite element analysis for the strength in dovetail joint bonding and the aluminum to 3D printed connections. Additional data reported are the time frame for the design and manufacturing of the system, budget, and an operational analysis of the wind turbine with concern for safety. Results are analyzed to determine the advantages in utilizing a hybrid additive manufacturing and aluminum construction for producing a more efficient vertical axis wind turbine. Techniques used in the production of this type of wind turbine blade are planned to be utilized in similar applications such as a lightweight hovercraft propeller blade design to be tested in future research projects.

History of Additive Manufacturing

2017 ◽  
pp. 1-24 ◽  
Keyword(s):  
Additive Manufacturing ◽  
3D Printing ◽  
Large Scale ◽  
Selective Laser Sintering ◽  
3D Printer ◽  
3D Objects ◽  
History Of ◽  
Pros And Cons ◽  
3D Printed ◽  
The Common

History of additive manufacturing started in the 1980s in Japan. Stereolithography was invented first in 1983. After that tens of other techniques were invented under the common name 3D printing. When stereolithography was invented rapid prototyping did not exists. Tree years later new technique was invented: selective laser sintering (SLS). First commercial SLS was in 1990. At the end of 20t century, first bio-printer was developed. Using bio materials, first kidney was 3D printed. Ten years later, first 3D Printer in the kit was launched to the market. Today we have large scale printers that printed large 3D objects such are cars. 3D printing will be used for printing everything everywhere. List of pros and cons questions rising every day.

scholarly journals Bone-inspired 3D printed structures for construction applications

2019 ◽  
Vol 14 (1) ◽  
pp. 111-124
Author(s):  
Roberto Naboni ◽  
Anja Kunic
Keyword(s):  
Additive Manufacturing ◽  
3D Printing ◽  
Computational Design ◽  
Bone Microstructure ◽  
Manufacturing Technology ◽  
Support Design ◽  
Efficient Construction ◽  
3D Printed ◽  
Viable Approach ◽  
Tectonic System

Overconsumption of resources is one of the greatest challenges of our century. The amount of material that is being extracted, harvested and consumed in the last decades is increasing tremendously. Building with new manufacturing technology, such as 3D Printing, is offering new perspectives in the way material is utilized sustainably within a construction. This paper describes a study on how to use Additive Manufacturing to support design logics inspired by the bone microstructure, in order to build materially efficient architecture. A process which entangles computational design methods, testing of 3D printed specimens, developments of prototypes is described. A cellular-based tectonic system with the capacity to vary and adapt to different loading conditions is presented as a viable approach to a material-efficient construction with Additive Manufacturing.

scholarly journals DLP 3D Printing Meets Lignocellulosic Biopolymers: Carboxymethyl Cellulose Inks for 3D Biocompatible Hydrogels

Polymers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1655 ◽  
Author(s):  
Giuseppe Melilli ◽  
Irene Carmagnola ◽  
Chiara Tonda-Turo ◽  
Fabrizio Pirri ◽  
Gianluca Ciardelli ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
3D Printing ◽  
Carboxymethyl Cellulose ◽  
Biomedical Applications ◽  
Digital Light Processing ◽  
Chemically Modified ◽  
Significant Step ◽  
3D Printed ◽  
Biomedical Field

The development of new bio-based inks is a stringent request for the expansion of additive manufacturing towards the development of 3D-printed biocompatible hydrogels. Herein, methacrylated carboxymethyl cellulose (M-CMC) is investigated as a bio-based photocurable ink for digital light processing (DLP) 3D printing. CMC is chemically modified using methacrylic anhydride. Successful methacrylation is confirmed by 1H NMR and FTIR spectroscopy. Aqueous formulations based on M-CMC/lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP) photoinitiator and M-CMC/Dulbecco’s Modified Eagle Medium (DMEM)/LAP show high photoreactivity upon UV irradiation as confirmed by photorheology and FTIR. The same formulations can be easily 3D-printed through a DLP apparatus to produce 3D shaped hydrogels with excellent swelling ability and mechanical properties. Envisaging the application of the hydrogels in the biomedical field, cytotoxicity is also evaluated. The light-induced printing of cellulose-based hydrogels represents a significant step forward in the production of new DLP inks suitable for biomedical applications.

Thermal Conductivity Testing Apparatus for 3D Printed Materials

2017 ◽  
Author(s):  
Tiffaney Flaata ◽  
Gregory J. Michna ◽  
Todd Letcher
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Additive Manufacturing ◽  
3D Printing ◽  
Polymer Composite ◽  
Heat Exchangers ◽  
Fused Deposition ◽  
3D Printed ◽  
Printed Materials ◽  
Metal Polymer

Additive manufacturing, the layer-by-layer creation of parts, was initially used for rapid prototyping of new designs. Recently, due to the decrease in the cost and increase in the resolution and strength of additively manufactured parts, additive manufacturing is increasingly being used for production of parts for end-use applications. Fused Deposition Modeling (FDM), a type of 3d printing, is a process of additive manufacturing in which a molten thermoplastic material is extruded to create the desired geometry. Many potential heat transfer applications of 3d printed parts, including the development of additively manufactured heat exchangers, exist. In addition, the availability of metal/polymer composite filaments, first used for applications such as tooling for injection molding applications and to improve wear resistance, could lead to increased performance 3d printed heat exchangers because of the higher thermal conductivity of the material. However, the exploitation of 3d printing for heat transfer applications is hindered by a lack of reliable thermal conductivity data for as-printed materials, which typically include significant void fractions. In this experimental study, an apparatus to measure the effective thermal conductivity of 3d printed composite materials was designed and fabricated. Its ability to accurately measure the thermal conductivity of polymers was validated using a sample of acrylic, whose conductivity is well understood. Finally, the thermal conductivities of various 3d printed polymer, metal/polymer composite, and carbon/polymer composite filaments were measured and are reported in this paper. The materials used are acrylonitrile butadiene styrene (ABS), polylactic acid (PLA), stainless steel/PLA, Brass/PLA, and Bronze/PLA.

3D Printing for Manufacturing Antique and Modern Musical Instrument Parts

2016 ◽  
Author(s):  
Frank Celentano ◽  
Nicholas May ◽  
Edward Simoneau ◽  
Richard DiPasquale ◽  
Zahra Shahbazi ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
3D Printing ◽  
Cloud Model ◽  
Low Cost ◽  
Sound Quality ◽  
Musical Instrument ◽  
Original Design ◽  
Manufacturing Method ◽  
3D Print ◽  
3D Printed

Professional musicians today often invest in obtaining antique or vintage instruments. These pieces can be used as collector items or more practically, as performance instruments to give a unique sound of a past music era. Unfortunately, these relics are rare, fragile, and particularly expensive to obtain for a modern day musician. The opportunity to reproduce the sound of an antique instrument through the use of additive manufacturing (3D printing) can make this desired product significantly more affordable. 3D printing allows for duplication of unique parts in a low cost and environmentally friendly method, due to its minimal material waste. Additionally, it allows complex geometries to be created without the limitations of other manufacturing techniques. This study focuses on the primary differences, particularly sound quality and comfort, between saxophone mouthpieces that have been 3D printed and those produced by more traditional methods. Saxophone mouthpieces are commonly derived from a milled blank of either hard rubber, ebonite or brass. Although 3D printers can produce a design with the same or similar materials, they are typically created in a layered pattern. This can potentially affect the porosity and surface of a mouthpiece, ultimately affecting player comfort and sound quality. To evaluate this, acoustic tests will be performed. This will involve both traditionally manufactured mouthpieces and 3D prints of the same geometry created from x-ray scans obtained using a ZEISS Xradia Versa 510. The scans are two dimensional images which go through processes of reconstruction and segmentation, which is the process of assigning material to voxels. The result is a point cloud model, which can be used for 3D printing. High quality audio recordings of each mouthpiece will be obtained and a sound analysis will be performed. The focus of this analysis is to determine what qualities of the sound are changed by the manufacturing method and how true the sound of a 3D printed mouthpiece is to its milled counterpart. Additive manufacturing can lead to more inconsistent products of the original design due to the accuracy, repeatability and resolution of the printer, as well as the layer thickness. In order for additive manufacturing to be a common practice of mouthpiece manufacturing, the printer quality must be tested for its precision to an original model. The quality of a 3D print can also have effects on the comfort of the player. Lower quality 3D prints have an inherent roughness which can cause discomfort and difficulty for the musician. This research will determine the effects of manufacturing method on the sound quality and overall comfort of a mouthpiece. In addition, we will evaluate the validity of additive manufacturing as a method of producing mouthpieces.

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