On the Simulation of 3D Printing Process by a Novel Meshless Analysis Procedure

ABSTRACTTo evaluate the thermal deformation induced by 3D Printing (Three Dimensional Printing) process, a novel meshless analysis procedure is established. To account for the heat transfer and solidification effects of each printing layer from liquid to solid phase transition, the layer temperature is measured by the implanted thermocouples. Based on the temperature variation measured, the printing layer temperature can be averaged and considered as uniform for thermal analysis. In addition, as observed by the deformation of the printed target through experiment, only linear thermal elastic analysis is performed.A rigorous algorithm for simulating the 3D Printing process is presented herein. Since the interpolation functions are no longer polynomials, a simple integration scheme using uniform integration points is applied to calculate the global stiffness matrix. Thus, the density and location of the integration points can be easily adjusted to fulfill the required accuracy. Further, for practical implementation, the simulation is also carried out by the concept of equivalent layer.Demonstrative cases of printing a rectangular PLA (Polylactic Acid) brick are tackled to prove the accuracy and efficiency of the proposed meshless analysis procedure. The effects of layer thickness, equivalent layer and slenderness ratio on the thermal deformation of the printed brick are also investigated.

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A Heuristic Scaling Strategy for Multi-Robot Cooperative Three-Dimensional Printing

Journal of Computing and Information Science in Engineering ◽

10.1115/1.4045143 ◽

2020 ◽

Vol 20 (4) ◽

Author(s):

Laxmi Poudel ◽

Chandler Blair ◽

Jace McPherson ◽

Zhenghui Sha ◽

Wenchao Zhou

Keyword(s):

3D Printing ◽

Fused Deposition Modeling ◽

Three Dimensional ◽

Evaluation Framework ◽

Geometric Constraints ◽

Mathematical Representation ◽

Printing Process ◽

Fused Deposition ◽

3D Printers ◽

Printing Time

Abstract While three-dimensional (3D) printing has been making significant strides over the past decades, it still trails behind mainstream manufacturing due to its lack of scalability in both print size and print speed. Cooperative 3D printing (C3DP) is an emerging technology that holds the promise to mitigate both of these issues by having a swarm of printhead-carrying mobile robots working together to finish a single print job cooperatively. In our previous work, we have developed a chunk-based printing strategy to enable the cooperative 3D printing with two fused deposition modeling (FDM) mobile 3D printers, which allows each of them to print one chunk at a time without interfering with the other and the printed part. In this paper, we present a novel method in discretizing the continuous 3D printing process, where the desired part is discretized into chunks, resulting in multi-stage 3D printing process. In addition, the key contribution of this study is the first working scaling strategy for cooperative 3D printing based on simple heuristics, called scalable parallel arrays of robots for 3DP (SPAR3), which enables many mobile 3D printers to work together to reduce the total printing time for large prints. In order to evaluate the performance of the printing strategy, a framework is developed based on directed dependency tree (DDT), which provides a mathematical and graphical description of dependency relationships and sequence of printing tasks. The graph-based framework can be used to estimate the total print time for a given print strategy. Along with the time evaluation metric, the developed framework provides us with a mathematical representation of geometric constraints that are temporospatially dynamic and need to be satisfied in order to achieve collision-free printing for any C3DP strategy. The DDT-based evaluation framework is then used to evaluate the proposed SPAR3 strategy. The results validate the SPAR3 as a collision-free strategy that can significantly shorten the printing time (about 11 times faster with 16 robots for the demonstrated examples) in comparison with the traditional 3D printing with single printhead.

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A Collaborative and Ubiquitous System for Fabricating Dental Parts Using 3D Printing Technologies

Healthcare ◽

10.3390/healthcare7030103 ◽

2019 ◽

Vol 7 (3) ◽

pp. 103 ◽

Cited By ~ 10

Author(s):

Wang ◽

Chen ◽

Lin

Keyword(s):

3D Printing ◽

Three Dimensional ◽

Mixed Integer ◽

Printing Process ◽

Planning Optimization ◽

Integer Quadratic Programming ◽

Ubiquitous System ◽

Independent Decision ◽

Mixed Integer Quadratic Programming ◽

And Control

Three-dimensional (3D) printing has great potential for establishing a ubiquitous service in the medical industry. However, the planning, optimization, and control of a ubiquitous 3D printing network have not been sufficiently discussed. Therefore, this study established a collaborative and ubiquitous system for making dental parts using 3D printing. The collaborative and ubiquitous system split an order for the 3D printing facilities to fulfill the order collaboratively and forms a delivery plan to pick up the 3D objects. To optimize the performance of the two tasks, a mixed-integer linear programming (MILP) model and a mixed-integer quadratic programming (MIQP) model are proposed, respectively. In addition, slack information is derived and provided to each 3D printing facility so that it can determine the feasibility of resuming the same 3D printing process locally from the beginning without violating the optimality of the original printing and delivery plan. Further, more slack is gained by considering the chain effect between two successive 3D printing facilities. The effectiveness of the collaborative and ubiquitous system was validated using a regional experiment in Taichung City, Taiwan. Compared with two existing methods, the collaborative and ubiquitous 3D printing network reduced the manufacturing lead time by 45% on average. Furthermore, with the slack information, a 3D printing facility could make an independent decision about the feasibility of resuming the same 3D printing process locally from the beginning.

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New Materials for 3D-Printing Based on Polycaprolactone with Gum Rosin and Beeswax as Additives

Polymers ◽

10.3390/polym12020334 ◽

2020 ◽

Vol 12 (2) ◽

pp. 334 ◽

Cited By ~ 4

Author(s):

Cristina Pavon ◽

Miguel Aldas ◽

Juan López-Martínez ◽

Santiago Ferrándiz

Keyword(s):

Tensile Strength ◽

3D Printing ◽

Mechanical Characterization ◽

Three Dimensional ◽

New Materials ◽

Elongation At Break ◽

Printing Process ◽

Gum Rosin ◽

The Matrix ◽

Natural Additives

In this work, different materials for three-dimensional (3D)-printing were studied, which based on polycaprolactone with two natural additives, gum rosin, and beeswax. During the 3D-printing process, the bed and extrusion temperatures of each formulation were established. After, the obtained materials were characterized by mechanical, thermal, and structural properties. The results showed that the formulation with containing polycaprolactone with a mixture of gum rosin and beeswax as additive behaved better during the 3D-printing process. Moreover, the miscibility and compatibility between the additives and the matrix were concluded through the thermal assessment. The mechanical characterization established that the addition of the mixture of gum rosin and beeswax provides greater tensile strength than those additives separately, facilitating 3D-printing. In contrast, the addition of beeswax increased the ductility of the material, which makes the 3D-printing processing difficult. Despite the fact that both natural additives had a plasticizing effect, the formulations containing gum rosin showed greater elongation at break. Finally, Fourier-Transform Infrared Spectroscopy assessment deduced that polycaprolactone interacts with the functional groups of the additives.

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Recent Cell Printing Systems for Tissue Engineering

International Journal of Bioprinting ◽

10.18063/ijb.2017.01.004 ◽

2017 ◽

Vol 3 (1) ◽

Cited By ~ 25

Author(s):

Hyeongjin Lee ◽

YoungWon Koo ◽

Miji Yeo ◽

SuHon Kim ◽

Geun Hyung Kim

Keyword(s):

Tissue Engineering ◽

Growth Factors ◽

3D Printing ◽

Cell Damage ◽

Three Dimensional ◽

Human Tissues ◽

Printing Process ◽

Cell Printing ◽

3D Space ◽

Printing Ink

Three-dimensional (3D) printing in tissue engineering has been studied for the bio mimicry of the structures of human tissues and organs. Now it is being applied to 3D cell printing, which can position cells and biomaterials, such as growth factors, at desired positions in the 3D space. However, there are some challenges of 3D cell printing, such as cell damage during the printing process and the inability to produce a porous 3D shape owing to the embedding of cells in the hydrogel-based printing ink, which should be biocompatible, biodegradable, and non-toxic, etc. Therefore, researchers have been studying ways to balance or enhance the post-print cell viability and the print-ability of 3D cell printing technologies by accommodating several mechanical, electrical, and chemical based systems. In this mini-review, several common 3D cell printing methods and their modified applications are introduced for overcoming deficiencies of the cell printing process.

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Novel Design and Three-Dimensional Printing of Variable Stiffness Robotic Grippers

Journal of Mechanisms and Robotics ◽

10.1115/1.4033728 ◽

2016 ◽

Vol 8 (6) ◽

Cited By ~ 20

Author(s):

Yang Yang ◽

Yonghua Chen ◽

Ying Wei ◽

Yingtian Li

Keyword(s):

3D Printing ◽

Degrees Of Freedom ◽

Shape Memory Polymer ◽

Three Dimensional ◽

Acrylonitrile Butadiene Styrene ◽

Variable Stiffness ◽

Analytical Models ◽

Printing Process ◽

Finger Joints ◽

Rotational Degrees Of Freedom

In this paper, a novel robotic gripper design with variable stiffness is proposed and fabricated using a modified additive manufacturing (hereafter called 3D printing) process. The gripper is composed of two identical robotic fingers and each finger has three rotational degrees-of-freedom as inspired by human fingers. The finger design is composed of two materials: acrylonitrile butadiene styrene (ABS) for the bone segments and shape-memory polymer (SMP) for the finger joints. When the SMP joints are exposed to thermal energy and heated to above their glass transition temperature (Tg), the finger joints exhibit very small stiffness, thus allow easy bending by an external force. When there is no bending force, the finger will restore to its original shape thanks to SMP's shape recovering stress. The finger design is actuated by a pneumatics soft actuator. Fabrication of the proposed robotic finger is made possible by a modified 3D printing process. An analytical model is developed to represent the relationship between the soft actuator's air pressure and the finger's deflection angle. Furthermore, analytical modeling of the finger stiffness modulation is presented. Several experiments are conducted to validate the analytical models.

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Fine Details Obtained by 3D Printing and Using Polymers

Materiale Plastice ◽

10.37358/mp.18.4.5056 ◽

2018 ◽

Vol 55 (4) ◽

pp. 474-477

Author(s):

Laurentiu Slatineanu ◽

Oana Dodun ◽

Gheorghe Nagit ◽

Margareta Coteata ◽

Gheorghe Bosoanca ◽

...

Keyword(s):

3D Printing ◽

Three Dimensional ◽

Printing Process ◽

Three Dimensional Printing ◽

Manufacturing Method ◽

Nozzle Orifice ◽

Systemic Analysis ◽

Dimensional Printing ◽

Printing Techniques ◽

Isosceles Triangles

The three-dimensional printing is a manufacturing method involving the addition of materials by using certain principles valid in printing techniques. There are various techniques of a three-dimensional printing method and the most of them could be applied inclusively to generate objects of polymers. The objective of the research presented in this paper was to analyze the capabilities of 3D printing process or equipment of generating fine details and to identify a way of evaluating these capabilities when using polyester PLA as filament material. The systemic analysis of the printing techniques which use a fused polymer filament deposition showed that there are some groups of factors able to affect the obtaining of fine details. An experimental research was designed in order to highlight the influence exerted by the diameter of the nozzle orifice and by the values of sharp angles of isosceles triangles on the heights of these triangles, thus obtaining an image concerning the possibilities of generating sharp edges by three-dimensional printing. To evaluate the capacity of the 3D printing process of obtaining thin walls, a spiral including linear segments with a decreasing thickness from 1 mm was also achieved on the test piece. By mathematical processing of the experimental results using a specialized software, empirical mathematical models were determined to evaluate the intensity of influences exerted by the two process input factors on the heights corresponding to isosceles triangles characterized by sharp angles.

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Solid-state foaming of acrylonitrile butadiene styrene through microcellular 3D printing process

Journal of Cellular Plastics ◽

10.1177/0021955x211009443 ◽

2021 ◽

pp. 0021955X2110094

Author(s):

Rupesh Dugad ◽

G Radhakrishna ◽

Abhishek Gandhi

Keyword(s):

3D Printing ◽

Three Dimensional ◽

Acrylonitrile Butadiene Styrene ◽

Average Cell Size ◽

Average Cell ◽

Printing Process ◽

Specific Strength ◽

Nozzle Temperature ◽

Printing Parameters ◽

Butadiene Styrene

The lightweight products with superior specific strength are in great demand in numerous applications such as automotive, aerospace, biomedical, sports, etc. This work focussed on the manufacturing of lightweight products using the cellular three dimensional (3D) printing process. In this work, the continuous microcellular morphology has been developed in a single foamed filament using 3 D printing of carbon-di-oxide (CO2) saturated acrylonitrile butadiene styrene (ABS) filaments. The microcellular structures with average cell size in the range of 6–1040 µm were developed. The influence of printing parameters; nozzle temperature, feed rate, and flow rate on the foam characteristics and cell morphology at different levels were investigated. The different kinds of observed foamed extrudate irregularities were discussed.

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FABRICATION CYCLES COMPARISON OF ASSEMBLIES AND MONOLITHIC PARTS MADE BY 3D PRINTING METHOD

International Journal of Modern Manufacturing Technologies ◽

10.54684/ijmmt.2021.13.3.158 ◽

2021 ◽

Vol 13 (3) ◽

pp. 158-163

Author(s):

Kinga Skrzek ◽

◽

Mariusz Piotr Hetmanczyk ◽

Keyword(s):

3D Printing ◽

Three Dimensional ◽

Post Processing ◽

Material Consumption ◽

Printing Process ◽

Practical Applications ◽

Energy Consuming ◽

Definition Of ◽

Printing Method ◽

Made In

The article presents an analysis of the time-consuming, energy-consuming, and cost-consuming nature of 3D printing a three-dimensional polymer components made in two separate approaches: assembly and monolith structure of various materials (automatic filament change required). The introduction includes the definition of 3D printing, its advantages and examples of practical applications, as well as the reason for undertaking the researches described in the article. The justification of the form of 3D sample models was discussed in detail, as well as the methodology adopted by the authors for comparing the print characteristics and the steps of the printing cycles (print preparation, the course of the printing process and post-processing). A comparison of the materials consumption in the phasess of manual and automatic filament change in the mixer were also described. The test printout was made on the Prusa i3 MK3S printer for filament deposition (FDM or FFF methods). For automatic filament mixing, the Palette 2 Pro device was used. The conclusions also include guidelines for the design and production of models made in one continuous printing cycle (using automatic filament feeding devices). Monolithic elements are less accurate, while elements with replaceable filaments are cheaper, less energy-consuming and the material consumption is lower.

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3D printing: a useful tool for the fabrication of artificial electromagnetic (EM) medium

Rapid Prototyping Journal ◽

10.1108/rpj-09-2014-0122 ◽

2016 ◽

Vol 22 (2) ◽

pp. 251-257 ◽

Cited By ~ 5

Author(s):

Xiaoyong Tian ◽

Ming Yin ◽

Dichen Li

Keyword(s):

3D Printing ◽

Design Methodology ◽

Three Dimensional ◽

Manufacturing Strategy ◽

Low Loss ◽

Printing Process ◽

Content Type ◽

Design And Manufacturing ◽

3D Printed ◽

Loss Characteristic

Purpose Artificial electromagnetic (EM) medium and devices are designed with integrated micro- and macro-structures depending on the EM transmittance performance, which is difficult to fabricate by the conventional processes. Three-dimensional (3D) printing provides a new solution for the delicate artificial EM medium. This paper aims to first review the applications of 3D printing in the fabrication of EM medium briefly, mainly focusing on photonic crystals, metamaterials and gradient index (GRIN) devices. Then, a new design and fabrication strategy is proposed for the EM medium based on the 3D printing process, which was verified by the implementation of a 3D 90o Eaton lens based on GRIN metamaterials. Design/methodology/approach A new design and manufacturing strategy driven by the physical (EM transmittance) performance is proposed to illustrate the realization procedures of EM medium based device with controllable micro- and macro-structures. Stereolithography-based 3D printing process is used to obtain the designed EM device, an GRIN Eaton lens. The EM transmittance of the Eaton lens was validated experimentally and by simulation. Findings A 3D 90o Eaton lens was realized based on GRIN metamaterials structure according to the proposed design and manufacturing strategy, which had the broadband (12-18 GHz) and low loss characteristic. The feasibility of 3D printing for the artificial EM medium and GRIN devices has been verified for the further real applications in the industries. Originality/value The applications of 3D printing in artificial EM medium and devices were systematically reviewed. A new design strategy driven by physical performance for the EM device was proposed and validated by the firstly 3D printed 3D Eaton lens.

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Design and Implementation of 3D Printing System for Continuous CFRP Composites

MATEC Web of Conferences ◽

10.1051/matecconf/201821301011 ◽

2018 ◽

Vol 213 ◽

pp. 01011 ◽

Cited By ~ 1

Author(s):

Ningda Han ◽

Jun Cheng ◽

Jiquan Yang ◽

Yijian Liu ◽

Wuyun Huang

Keyword(s):

Carbon Fiber ◽

3D Printing ◽

Three Dimensional ◽

Printing Technology ◽

Printing Process ◽

Three Dimensional Printing ◽

Cfrp Composites ◽

Continuous Carbon Fiber ◽

Printing System ◽

Dimensional Printing

The rapid and low-cost manufacturing of continuous Carbon Fiber Reinforced Polymer (CFRP) composites using 3D printing technology is a hot topic in the field of composite materials’ research. Due to the continuity and infusibility of the long carbon fiber, a series of problems such as loosening of fiber, breakage, and nozzle clogging occurred in the printing process, which result in poor surface quality and performance in the printed product. This paper aims to solve these problems based on the researches and optimizations of three-dimensional printing technology for continuous CFRP composite components. Firstly, the coupling mechanism of continuous fiber and resin polymer in the flow path of nozzle is analyzed, the finite element simulation models of flow field and temperature field of CFRP three-dimensional printing are established by using ANSYS CFX software, and the coupling characteristics and interface performance in the printing process are studied. Then, based on the results of simulation analysis, a modification method of the surface coating film is applied, and a special modification solution is configured to modify the surface of the carbon fiber so as to increase its strength and bondability with the molten resin. Finally, the mechanical structure of the three-dimensional printing system of continuous CFRP components is designed to achieve the synchronization of printing and fiber modification. Considering the continuity of continuous carbon fiber, this paper proposed a new method of printing path design called “unicursal” for continuous CFRP parts, that is, when designing and planning a three-dimensional print path, it ensured that there is no interruption in the printing process, so as to achieve carbon fiber continuity in composite parts. The reliability and superiority of the printing system designed in this paper are confirmed by printing of the composite parts.

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