Material Extrusion Processes Research Articles

Geopolymer additive manufacturing: A review

This paper analyzes the current development of additive manufacturing (AM) technologies exploiting geopolymers (GPs) as promising green and sustainable 3D printable aluminosilicate inorganic materials. Material design and processing strategies to achieve or enhance three-dimensional printability of various geopolymer systems are summarized. The main methods of GPs additive manufacturing based on material extrusion and powder-based printing processes are considered. Their features, advantages, and limitations are scrutinized. There is presented a brief description and a principle of operation of the varieties of 3D printers, with whose help these fabrication approaches are implemented. Fresh and hardened state properties of 3D printed GPs are discussed in detail from the point of view of chemical reactions and structural transformations occurring in the material. The areas and specific examples of the application of advanced printable geopolymer materials and products are surveyed. The main current challenges, perspectives and directions of future work required to improve this technology have been delineated.

A parameterized g-code compiler for scaffolds 3D bioprinting

Parameterization of geometries for g-code compiling arises as an attractive option to control 3D printers. Based on the geometry of the object to be fabricated, and the construction platform, or the container where de material will be deposited, tool-paths can be obtained and compiled in the g-code format. This last includes the tool-path coordinates and all the process parameters. Thus, without the need for CAD(Computer-Aided Design) software or slicers, it is possible to obtain g-code files quickly. This article reports the development of a g-code compiler software called BioScaffolds PG V2.0.; it is compatible with open-source desktop 3D printers and is oriented to be used in the 3D bioprinting field by material extrusion processes. The software was programmed using the VB.NET language and enables the scaffolds fabrication in the construction platform, inside Petri dishes, or in cell culture plates. The deposition process was also parameterized; it is calculated as a function of the tool-path and considers the mass conservation according to the printing head geometry. The graphical user interface allows easily set the process and geometrical parameters to generate a g-code file. As validated through CAM (Computer-Aided Manufacturing) simulations and hydrogel samples fabrication, the parameterized g-codes were successfully compiled. First, the hydrogel-based ink was formulated and rheologically characterized. Then, it was used to test the software in a desktop 3D printer. Once validated, the ink was used to formulate a bioink to perform a 3D bioprinting validation. The in vitro qualitative and quantitative assays were performed using Incucyte live-cell analysis up to 4 days of culture. The results showed cellular proliferation in the printed samples, which is a promising in vitro result. Then, considering that open-source 3D printers are widely used for bioprinting, this free software could help to expand and automate applications in this field.

In-situ adaptive thermal simulation method for predicting and avoiding hotspots in material extrusion processes

PurposeThis study aims to design a novel strategy to avoid thermal defects in three-dimensional (3D) printing processes. A combination of subroutines and utility routines allows for in situ variations of the key process parameters (KPP) in the thermal simulation and produces by post-processing the output an updated machine code for enhanced quality of the printed part in a single iteration.Design/methodology/approachThe input data for the thermal simulation were obtained by characterising an acrylonitrile butadiene styrene filament and calibrating an Ultimaker S5 printer. Abaqus subroutines were used to accurately simulate the continuous deposition of molten material. A utility routine extracted the nodal temperatures during simulation and detected regions that were prone to overheating. We developed a method, enabling the introduction of variable process parameters in the thermal simulation and validated it by printing several test geometries.FindingsThe results of the thermal simulation indicate that decreasing the print speed enhances the amount of heat dissipated to the environment. Therefore, it is an efficient way to avoid overheating of the printed geometry. The validation geometries showed improvements when adapting the print speed.Originality/valueThis approach is the first to demonstrate the potential of variable process parameters using implemented routines in the thermal process simulation. Here, the focus is on predicting and avoiding thermal hotspots. However, more potential can be obtained by enabling the prediction and adaptation of KPP to ensure mechanical performance. This would be an alternative way to tackle the cost- and time-inefficient post-processing of 3D-printed parts.

Analytical and Numerical Models of Thermoplastics: A Review Aimed to Pellet Extrusion-Based Additive Manufacturing.

Recent developments in additive manufacturing have moved towards a new trend in material extrusion processes (ISO/ASTM 52910:2018), dealing with the direct extrusion of thermoplastic and composite material from pellets. This growing interest is driven by the reduction of costs, environmental impact, energy consumption, and the possibility to increase the range of printable materials. Pellet additive manufacturing (PAM) can cover the same applications as fused filament fabrication (FFF), and in addition, can lead to scale towards larger workspaces that cannot be covered by FFF, due to the limited diameters of standard filaments. In the first case, the process is known as micro- or mini-extrusion (MiE) in the literature, in the second case the expression big area additive manufacturing (BAAM) is very common. Several models are available in literature regarding filament extrusion, while there is a lack of modeling of the extrusion dynamics in PAM. Physical and chemical phenomena involved in PAM have high overlap with those characterizing injection molding (IM). Therefore, a systematic study of IM literature can lead to a selection of the most promising models for PAM, both for lower (MiE) and larger (BAAM) extruder dimensions. The models concerning the IM process have been reviewed with this aim: the extraction of information useful for the development of codes able to predict thermo-fluid dynamics performances of PAM extruders.

Material extrusion and sintering of binder-coated zirconia: Comprehensive characterizations

Material extrusion processes have been increasingly employed in the fabrication of advanced ceramics in the aerospace, automotive, and biomedical fields. Such processes—which involve printing compositions containing ceramic powders and sacrificial binder, debinding the binders, and sintering the parts to obtain pure ceramics—can be used to produce more complex structures than traditional ceramic manufacturing techniques. In this study, a rod-shaped feedstock comprised of binder-coated zirconia containing 87 wt% zirconia was supplied to a motorized piston extruder in a customized 3D printer to fabricate green ceramic structures, and the structures were then subjected to debinding and sintering. A comprehensive set of characteristics were examined: the thermal and rheological properties of the feedstock, the printability of the feedstock, the influence of the layer thickness and raster angle on the surface roughness and flexural/tensile/compressive strengths of the sintered zirconia, Vickers hardness, relative density and porosity, shrinkage behavior, and the micro/macro structure of green and sintered 3D-printed zirconia structures. The mechanical properties and relative density were found to increase as the layer thickness decreased. The maximum flexural, tensile, and compressive strengths of the sintered zirconia were 435, 36.13, and 689 MPa, respectively, and the relative density was 98.85% at a layer thickness of 200 µm. The comprehensive characteristics of 3D printed green and sintered zirconia that were obtained in this study can facilitate the successful 3D printing of ceramics. Moreover, the characterization contributes to an understanding of the effects of additive manufacturing process parameters on the physical and mechanical properties of ceramic materials and can aid in optimizing the performance and properties of 3D printed ceramic structures. • Comprehensive characterizations of green and sintered zirconia parts was conducted. • A binder-coated zirconia was developed for material extrusion additive manufacturing. • A piston-based extrusion process was developed to fabricate highly dense zirconia parts. • Defect-free zirconia structures were produced using solvent and thermal debinding, followed by sintering.

The effect of process parameters in material extrusion processes on the part surface quality: A review

Material Extrusion Additive Manufacturing (MEAM) method has been focused for its capability to fabricate complex geometrical parts without any specific tooling and its suitability for customized parts production. Many studies have recognized the role of MEAM methods in small scale manufacturing and in-house fabrication. But higher surface roughness in material extrusion’ parts is a major drawback which limits its industrial applications. The obtained surface roughness of fabricated parts beyond the desired limits needs further investigations. Since the surface roughness in the parts can't be totally eliminated but it can be reduced significantly. Various researchers have quantified the effect of extrusion parameters and some of them have worked on the post processing methods. This literature work focuses on the effect of majorly used extrusion variables and post processing techniques for the improvements of surface quality.

Estimation and Improvement of the Achievable Tolerance Interval in Material Extrusion Additive Manufacturing through a Multi-State Machine Performance Perspective

Dimensional quality is still a major concern in additive manufacturing (AM) processes and its improvement is key to closing the gap between prototype manufacturing and industrialized production. Mass production requires the full working space of the machine to be used, although this arrangement could lead to location-related differences in part quality. The present work proposes the application of a multi-state machine performance perspective to reduce the achievable tolerance intervals of features of linear size in material extrusion (MEX) processes. Considering aspecific dimensional parameter, the dispersion and location of the distribution of measured values between different states are analyzed to determine whether the production should be treated as single-state or multi-state. A design for additive manufacturing strategy then applies global or local size compensations to modify the 3D design file and reduce deviations between manufactured values and theoretical values. The variation in the achievable tolerance range before and after the optimization of design is evaluated by establishing a target machine performance index. This strategy has been applied to an external MEX-manufactured cylindrical surface in a case study. The results show that the multi-state perspective provides a better understanding of the sources of quality variability and allows for a significant reduction in the achievable tolerance interval. The proposed strategy could help to accelerate the industrial adoption of AM process by reducing differences in quality with respect to conventional processes.

Product Design by Additive Manufacturing for Water Environments: Study of Degradation and Absorption Behavior of PLA and PETG.

Additive manufacturing technologies are shifting from rapid prototyping technologies to end use or final parts production. Polymeric material extrusion processes have been broadly addressed with a specific definition of all parameters and variables for all different of technologies approaches and materials. Recycled polymeric materials have been studied due to the growing importance of the environmental awareness of the contemporary society. Beside this, little specific research has been found in product development applications for AM where the printed parts are in highly moisture environments or surrounded by water, but polymers have been for long used in such industries with conventional manufacturing approaches. This work focuses on the analysis and comparison of two different additively manufactured polymers printed by fused filament fabrication (FFF) processes using desktop-size printers to be applied for product design. The polymers used have been a recycled material: polyethylene terephthalate glycol (PETG) and polylactic acid (PLA). Degradation and water absorption behaviors of both materials are presented, analyzed and discussed in this paper, where different samples have been immersed in saturated solutions of water with maritime salt and sugar together with a control sample immersed in distilled water. The samples have been dimensionally and weight-controlled weekly as well as microscopically analyzed to understand degradation and absorption processes that appear in the fully saturated solutions. The results revealed how the absorption process is stabilized after a reduced number of weeks for both materials and how the degradation process is more remarked in the PLA material due to its organic nature.

Advances in additive manufacturing of shape memory polymer composites

Purpose A review on additive manufacturing (AM) of shape memory polymer composites (SMPCs) is put forward to highlight the progress made up to date, conduct a critical review and show the limitations and possible improvements in the different research areas within the different AM techniques. The purpose of this study is to identify academic and industrial opportunities. Design/methodology/approach This paper introduces the reader to three-dimensional (3 D) and four-dimensional printing of shape memory polymers (SMPs). Specifically, this review centres on manufacturing technologies based on material extrusion, photopolymerization, powder-based and lamination manufacturing processes. AM of SMPC was classified according to the nature of the filler material: particle dispersed, i.e. carbon, metallic and ceramic and long fibre reinforced materials, i.e. carbon fibres. This paper makes a distinction for multi-material printing with SMPs, as multi-functionality and exciting applications can be proposed through this method. Manufacturing strategies and technologies for SMPC are addressed in this review and opportunities in the research are highlighted. Findings This paper denotes the existing limitations in the current AM technologies and proposes several directions that will contribute to better use and improvements in the production of additive manufactured SMPC. With advances in AM technologies, gradient changes in material properties can open diverse applications of SMPC. Because of multi-material printing, co-manufacturing sensors to 3D printed smart structures can bring this technology a step closer to obtain full control of the shape memory effect and its characteristics. This paper discusses the novel developments in device and functional part design using SMPC, which should be aided with simple first stage design models followed by complex simulations for iterative and optimized design. A change in paradigm for designing complex structures is still to be made from engineers to exploit the full potential of additive manufactured SMPC structures. Originality/value Advances in AM have opened the gateway to the potential design and fabrication of functional parts with SMPs and their composites. There have been many publications and reviews conducted in this area; yet, many mainly focus on SMPs and reserve a small section to SMPC. This paper presents a comprehensive review directed solely on the AM of SMPC while highlighting the research opportunities.

Reusable support for additive manufacturing

Abstract Additive manufacturing (AM) processes such as material extrusion and vat photopolymerization all require supports to print parts with overhang features. These additional supports using the same or different materials are a waste of materials since they need to be removed after the three-dimensional (3D) printing process and cannot be reused. The printing of supports is also time-consuming for the nozzle-based material extrusion processes. A new type of reusable support has been developed to address the support-related challenges in AM. The main idea is to use a set of dynamically controlled metal pins as a programmable building platform. In the layer fabrication, the metal pins will move up one-layer thickness after the printing of each layer. Also, each metal pin will automatically stop at a specified height that is determined by a combination of metal tubes, magnetic discs, and magnetic rings. Additional supports can be 3D-printed on the top surface of the metal pins, while the amount of the supports is dramatically reduced. After the printing process, the metal rods can be separated from the part and reset for the next printing job. A prototype system has been constructed to demonstrate the reusable support principle. The layout optimization and toolpath generation algorithms for the reusable support are also presented. The experimental results of several test cases show an average of nearly 40% saving on the printing time and material with increased reliability and robustness. The reusable support provides a support generation strategy that could be beneficial to other AM processes such as stereolithography and selective laser melting.

Part decomposition and evaluation based on standard design guidelines for additive manufacturability and assemblability

In comparison to traditional manufacturing, Additive Manufacturing (AM) provides unique capability to create complex part geometries. However, AM often suffers from its own limitations, such as the need for support structures, the presence of the stair-step effect and long build time. Recently, Part Decomposition (PD) techniques have been deployed to overcome these limitations. PD refers to the process of decomposing an original model into sub-assemblies. In the literature, PD studies have often proposed specific design considerations to evaluate that an original model is properly decomposed. For a comprehensive perspective, we address common and essential design considerations based on the standard design guidelines for AM in ISO/ASTM 52910. Since the standard design guidelines cover a variety of perspectives, we focus on the design considerations for additive manufacturability and assemblability . Then, evaluation indicators are defined for the design considerations as mathematical forms to quantitatively evaluate decomposed parts. The evaluation indicators are applied to the optimization of PD. As an optimization approach, a genetic algorithm (GA) is employed to recursively evaluate the outcomes of PD. In the GA, PD processes including concave feature-based PD (CPD) and convex feature-based PD (VPD) are considered to elaborately decompose an original model. In case studies, 9 models are compared with their decomposed parts for material extrusion (ME) and vat photopolymerization (VP) processes. On average, the build time decreases by 21% for ME and 70% for VP and the material consumption is reduced by 27% for ME and 22% for VP. Furthermore, when our optimization approach is compared to another similar method, Near-convex Decomposition (NCD) , the material consumption is reduced by an average of 26% and 62% for ME and VP processes, respectively. • Design considerations for part decomposition are organized in terms of additive manufacturability and assemblability. • To quantitatively assess decomposition, evaluation indicators are developed based on the design considerations. • An optimization method for part decomposition is suggested to represent how the evaluation indicators are applied.

Investigation of Parameter Spaces for Topology Optimization With Three-Dimensional Orientation Fields for Multi-Axis Additive Manufacturing

Abstract The layer-by-layer deposition process used in material extrusion (ME) additive manufacturing results in inter- and intra-layer bonds that reduce the mechanical performance of printed parts. Multi-axis (MA) ME techniques have shown potential for mitigating this issue by enabling tailored deposition directions based on loading conditions in three dimensions (3D). Planning deposition paths leveraging this capability remains a challenge, as an intelligent method for assigning these directions does not exist. Existing literature has introduced topology optimization (TO) methods that assign material orientations to discrete regions of a part by simultaneously optimizing material distribution and orientation. These methods are insufficient for MA–ME, as the process offers additional freedom in varying material orientation that is not accounted for in the orientation parameterizations used in those methods. Additionally, optimizing orientation design spaces is challenging due to their non-convexity, and this issue is amplified with increased flexibility; the chosen orientation parameterization heavily impacts the algorithm’s performance. Therefore, the authors (i) present a TO method to simultaneously optimize material distribution and orientation with considerations for 3D material orientation variation and (ii) establish a suitable parameterization of the orientation design space. Three parameterizations are explored in this work: Euler angles, explicit quaternions, and natural quaternions. The parameterizations are compared using two benchmark minimum compliance problems, a 2.5D Messerschmitt–Bölkow–Blohm beam and a 3D Wheel, and a multi-loaded structure undergoing (i) pure tension and (ii) three-point bending. For the Wheel, the presented algorithm demonstrated a 38% improvement in compliance over an algorithm that only allowed planar orientation variation. Additionally, natural quaternions maintain the well-shaped design space of explicit quaternions without the need for unit length constraints, which lowers computational costs. Finally, the authors present a path toward integrating optimized geometries and material orientation fields resulting from the presented algorithm with MA–ME processes.

An Overview of Material Extrusion Troubleshooting

Material extrusion (ME) systems offer end-users with a more affordable and accessible additive manufacturing (AM) technology compared to other processes in the market. ME is often used to quickly produce low-cost prototyping with the freedom of scalability where parts can be produced in different geometries, quantities and sizes. As the use of desktop ME machines has gained widespread adoption, this review paper discusses the key design strategies and considerations to produce high quality ME parts, as well as providing actional advice to aid end-users in quickly identifying and efficiently troubleshooting issues since current information is often fragmented and incomplete. The systemic issues and solutions concerning desktop ME processes discussed are not machine-specific, covering categories according to printer-associated, deposition-associated and print quality problems. The findings show that the majority of issues are associated with incorrect printer calibration and parameters, hardware, material, Computer Aided Design (CAD) model and/or slicing settings. A chart for an overview of ME troubleshooting is presented allowing designers and engineers to straightforwardly determine the possible contributing factors to a particular problem.

Supportless Lattice Structures for Energy Absorption Fabricated by Fused Deposition Modeling.

Additively manufactured cellular structures represent a promising engineering design concept for making customized products where user-specific mechanical properties are required. One of the major challenges in the additive manufacturing (AM) process is removal of unwanted support structures from the lattice. The support structure consumes extra material, printing time, and energy for manufacturing. Postprinting, it needs extensive postprocessing work to remove it from the lattice structure chemically or mechanically. In the case of flexible materials such as thermoplastic polyurethane (TPU), removing the support structure from the lattice is very difficult with the material extrusion process. In this article, a new type of a shell-shaped lattice structure inspired by sea urchin (SU) morphology is designed. This lattice can be additively manufactured by material extrusion processes such as fused deposition modeling (FDM) without requiring any support structures. The mechanical properties of the proposed structure, such as stiffness and energy absorption during loading and unloading, have been evaluated as they are important for cushioning. The compressive results indicate that the stiffness property is almost twice as high compared with the benchmarked, bending-dominated, body-centered cubic (BCC) lattice structure of the same relative density and ethylene vinyl acetate (EVA) foam. Energy absorption is almost equal to the BCC lattice and 20% better than EVA foam. Last, a predictive model on stiffness behavior and energy return was developed to facilitate a systematic way to select optimal densities of the SU lattice structure for energy-absorbing applications. Visual inspection has also revealed that there is no sagging or failure of the lattice, which reduced the manufacturing time and postprocessing time, saving a significant amount of material without compromising on quality. Supportless lattice printing was also validated by printing the specimen with a different FDM printer and TPU filament. A possible application for supportless lattice structures can be for AM of customized shoe midsoles at low cost, ski boots, tires, automotive crush boxes, or any other energy-absorbing structures.

Feature-based Print Method for Multi-Axis Material Extrusion in Additive Manufacturing

Additive manufacturing technology develops very dynamically in terms of new processes, materials and areas of application. Cost intensive post processing, especially removal of support structures is one big challenge in material extrusion (ME) processes and drives development of new machine designs like 5-axis printers. Currently, time intensive manual programming of machine code is necessary in order to slice parts for multi-axis printing. This paper deals with an experimental study of state-of-the-art 3D-printers developing a feature-based print method for multi-axis systems by using an adaptive layer height while reducing support structures and stair-step effect. Computer-aided manufacturing for ME is investigated in order to develop a geometric model for trajectory planning.

The Design of Application Model using Manufacturing Data in Protection Film Process for Smart Manufacturing Innovation

세계 제조업은 장기적인 경기침체, 노동 원가 및 원자재 가격 상승으로 성장 한계에 봉착하게 되었으며, 이에 대한 해결방안으로 ICT와 센서 기술을 바탕으로 제조업의 4차 산업혁명을 진행하고 있다. 이러한 흐름에 따라 화학 산업에서의 스마트공장 보급 확산과 스마트제조 기술 향상을 위해, 본 논문은 스마트 제조혁신을 위한 보호필름 공정 제조데이터 활용모델의 설계를 제안한다. 보호필름 공정 중에서 원료 배합 및 교반, 압출, 그리고 검수 공정에 대해서 온도, 압력, 습도, 그리고 동영상 및 열화상의 제조 데이터를 획득한다. 또한 획득된 제조 데이터는 대용량 스토리지에 저장되며, AI 서비스에 의한 시계열 및 이미지 분석과 시각화가 진행된다.The global manufacturing industry has reached the limit to growth due to a long-term recession, the rise of labor cost and raw material. As a solution to these difficulties, we promote the 4th Industry Revolution based on ICT and sensor technology. Following this trend, this paper proposes the design of a model using manufacturing data in the protection film process for smart manufacturing innovation. In the protective film process, the manufacturing data of temperature, pressure, humidity, and motion and thermal image are acquired by various sensors for the raw material blending, stirring, extrusion, and inspection processes. While the acquired manufacturing data is stored in mass storage, A.I. platform provides time-series image analysis and its visualization.

Virtual bead representation and surface roughness evaluation challenges for additive manufacturing material extrusion processes

Additive manufacturing (AM) processes, such as material extrusion, are part of a popular growing technology field; with limited human assistance required and advanced rapid prototyping capabilities, this technology is advertised to have limitless possibilities. The common challenge faced by users is a lack of design control of the surface roughness, which is highlighted by a characteristic “stair case” layering effect at the boundary. Focusing on material extrusion processes, the goal of this research is to model representative bead shapes, and highlight the surface roughness challenges for assessing boundary-fill regions. Various bead shapes are explored and compared through virtual simulation. Unique material extrusion AM-related issues arise, and it is shown that machining solutions may not provide the desired surface smoothness. This research illustrates that specific physical and virtual assessment tools and standards need to be further developed to convey surface roughness attributes for material extrusion additive manufactured components.

3D Printing and Characterization of Hydroxypropyl Methylcellulose and Methylcellulose for Biodegradable Support Structures

Abstract Additive manufacturing process based on fused deposition modeling (FDM) and material extrusion (ME) typically use thermoplastic materials like ABS, PLA, or nylon to fabricate parts layer-by-layer. In order to build a part successfully with complex features such as pores or holes or irregular shapes, the build part requires support structures to hold the deposited material and to prevent collapse of the finished parts before solidification. The support material acts as a sacrificial layer that should be easily removed later on by chemicals/enzymes, or broken by mechanical force. The present support materials used with FDM technology have challenges of poor dissolvability in chemical solution and difficulty to be removed from the finished part. In addition, these support materials are usually petroleum based which has a negative impact on the environment. The goal of the project is to identify a suitable biomaterial for support structures that will eliminate the challenges of poor dissolvability and toxic waste generated by the current material. This paper is focused on extrusion-based 3D printing process of thermoset biopolymers to fabricate support structures. In this study, three biodegradable cellulose derivatives, i.e. methylcellulose (MC) A4M, HPMC K4M, and hydroxypropyl methylcellulose (HPMC) E4M, with different degree of substitution of hydroxyl group were used. We investigated the effect of concentrations (8, 10, and 12% w/v) of all three cellulose derivatives on the rheological properties for understanding their printability. The rheological analysis revealed that all hydrogels exhibit shear-thinning properties with relatively low yield stress. At the same concentration, the apparent viscosity of HPMC K4M tended to be higher than HPMC E4M, followed by MC A4M. Effects of printing parameters (extrusion rate, nozzle diameter, and printing speed) were optimized to obtain the desired three-dimensional structures. The sample of 12% MC A4M and 12% w/v HPMC K4M showed higher complex shear modulus than other materials, which indicated higher rigidity and shape retention capacity of the printed parts. The ideal material for extrusion during printing and least deformation after printing was also observed for 12% MC A4M, which indicated a relationship between rheological properties and printability. The water dissolution of the MC and HPMC hydrogels allowed easy removal of the support structures from the build material. Biopolymers like MC and HPMC, when 3D printed as a support material via ME processes, help in moving closer towards sustainable manufacturing.

Design and manufacture of life size human model using material extrusion and vat photopolymerization additive processes

Nowadays, Additive Manufacturing (AM) is increasingly being used in various fields of medicine. Using Material Extrusion additive process – Fused Filament Fabrication (FFF) method are produced 3D models of organs or body parts designed for preoperative planning, individual prosthetic and orthopaedic appliances and others. The Vat Photopolymerization additive process – Stereolithography (SLA) method is used to produce precision hearing aids, wearable assist devices, prosthetics, orthotics and so on. The content of the article describes the process of designing and manufacturing the life size human model to show the possibilities and advantages of using selected additive methods in the field of medicine and thus pointing out the versatility of using the AM technology on a concrete example. The aim of thisarticle is to provide an up-to-date practical application of FFF and SLA additive methods in the fast-growing field of AM and to present to the reader a specific example of the use of AM with the idea of raising a better general understanding and supporting research into the use of AM technology in medicine.

The FaaS system using additive manufacturing for personalized production

PurposeIn this paper, a three-dimensional (3D) printer-based manufacturing line and supporting system, which supports personalized/customized manufacturing for individual businesses or start-up companies, was studied to evaluate the practicality of using additive manufacturing for personalization/mass customization.Design/methodology/approachFirst, factory-as-a-service (FaaS) system, which provides factory as a service to customers, was proposed and designed to manufacture various products within a distributed manufacturing environment. This system includes 3D printer-based material extrusion processes, vapor machine/computer numerical control machines as post-processes and assembly and inspection processes with an automated material handling robot in the factory. Second, a virtualization module for the FaaS factory was developed using a simulation model interfaced with a cloud-based order and production-planning system and an internet-of-things-based control and monitoring system. This is part of the system for manufacturing operations, which is capable of dynamic scheduling in a distributed manufacturing environment. In addition, simulation-based virtual production was conducted to verify and evaluate the FaaS factory for the target production scenario. Main information of the simulation also has been identified and included in the virtualization module. Finally, the established system was applied in a sample production scenario to evaluate its practicality and efficiency.FindingsAdditive manufacturing is a reliable, feasible and applicable technology, and it can be a core element in smart manufacturing and the realization of personalization/mass customization.Originality/valueVarious studies on additive manufacturing have been conducted with regard to replacing the existing manufacturing methods or integrating with them, but these studies mostly focused on materials or types of additive manufacturing, with few advanced or applied studies on the establishment of a new manufacturing environment for personalization/mass customization.