Nominal elastic modulus assessment in 3D-printed components under varying printing parameters using Bayesian methods and random forest surrogate modeling

The expanding range of materials available for 3D printing is driving its widespread adoption in advanced fields. As 3D printing becomes increasingly prevalent in the manufacturing of industrial components, its advantages in accommodating complex geometries and reducing material waste are attracting significant attention. Acquiring and applying precise elastic properties of materials during structural design is crucial for ensuring part safety and consistency. However, non-destructive mechanical property assessment methods remain limited. In this paper, we propose an efficient surrogate model, built using a Bayesian model updating approach combined with a random forest algorithm, to achieve high-precision calibration of material elastic constants. In the experiment, samples were 3D printed using fused deposition modeling, and modal information was obtained using operational modal analysis with one end fixed to simulate cantilever beam boundary conditions. Parameter updating was then performed within a Bayesian Markov Chain Monte Carlo framework. The deviation between the updated calculated frequencies and the measured frequencies was significantly reduced, and the Modal Assurance Criterion value between the updated calculated mode shapes and the measured mode shapes was higher than 0.99, demonstrating the accuracy of the updated parameters. Compared to traditional destructive testing methods, the proposed method directly calibrates the structural elastic modulus at the component level without affecting the normal use of the component, providing a more practical approach for the analysis and research of material properties in 3D printing additive manufacturing. The related technology can be extended to other structural forms of 3D-printed products.

This paper presents a procedure to estimate unmeasured rotation mode shapes of a test structure as a linear combination of those of the corresponding finite-element (FE) model. In this procedure, weighting coefficients for each mode shape combined are determined by comparing experimentally measured translation mode shapes with analytical mode shapes of the FE model. Since the accuracy of the estimated strongly depends on the selection of the mode shapes combined, a method based on the modal assurance criterion (MAC) values between experimental and analytical translation mode shapes for assessing the significance of mode shapes to be combined is proposed. The proposed method is shown to be suitable for a proper selection of mode shapes through a numerical example using a frame structure model. In addition, a practical technique to use the MAC values as the mode selection indicator under incomplete conditions of the measurements of translation mode shapes is suggested.

The widespread use of digital imaging can now be combined with additive three-dimensional (3D) printing, changing traditional clinical dentistry, especially in challenging cases. Visualizing the bone and soft tissue anatomy using computed tomography (CT) and intraoral scanning generated digital files that can be further processed for 3D printing. Among the popular 3D printing approaches, fused filament fabrication (FFF) and stereolithography (SLA) are broadly used due to their rapid production, precision, and ease of use. The current case series outlines three challenging clinical scenarios where a combination of CT and intraoral scans were utilized for digital planning. FFF multicolor anatomical models and SLA surgical guides were produced using 3D printing technology. The first case outlines the utility of this approach to place the optimal surgical window at the lateral sinus lift with anticipated difficult access. In the second case, distinct sites for autogenous bone harvesting were identified while preserving critical adjacent structures with surgical simulation. Finally, the third case outlines this strategy for optimal surgical access to expose an impacted second premolar. Both clinicians and patients benefited from the educational use of FFF‒SLA 3D-printed models, and all cases were successfully treated without complications. These cases demonstrate the significant utility of these digital technologies and rapid prototyping for improved pre-surgical planning, patient motivation, and didactic training that contribute to improved quality of clinical care. To the authors' knowledge, this is the first case reports employing both fused filament fabrication (FFF) and stereolithography (SLA) printing techniques in dental surgery. This innovative approach addresses a range of clinically challenging scenarios presented in this report. Computed tomography (CT) and intraoral scanning are essential for three-dimensional (3D) reconstruction. Specialized software is required to design the guide with precise specifications, and FFF and SLA printers are necessary for fabricating the 3D model. Three-dimensional reconstruction can be time-intensive, particularly when manual segmentation is necessary. Acquiring proficiency in the software may require additional time, and multicolor 3D printing also demands extended printing durations. This study explores how digital imaging and three-dimensional (3D) printing can improve complex dental surgeries. Using tools such as computed tomography scans and intraoral scans, dentists can create detailed 3D models of a patient's bone and soft tissues. Two popular 3D printing methods-fused-filament fabrication (FFF) and stereolithography (SLA)-were used to make these models, which help with surgical planning. The study includes three cases where 3D-printed models were used to prepare for difficult dental procedures. In the first case, the 3D model helped plan the best way to access a difficult area for sinus surgery. The second case used the model to identify the best sites for bone harvesting. The third case used the model to plan how to safely expose an impacted tooth. These helped both the dentist and the patient understand the procedure better. All surgeries were successful, demonstrating how FFF and SLA 3D printing enhance planning, making advanced dental surgeries safer and more efficient.

In order to identify the supporting condition of cable-stayed bridges with semi-floating system by using the measured mode shapes, this paper proposed an actual supporting condition evaluation method of cable-stayed bridges based on the indicator of modal assurance criterion (MAC). Firstly, the measured mode shapes and theoretical mode shapes under different supporting conditions could be obtained. Then the corresponding MAC indicator values were calculated, which would be compared to evaluate the supporting condition of bridges. The experiment results revealed that the MAC values between the measured mode shapes and theoretical mode shapes were in good agreement with MAC values above 0.9, which indicated that the actual structural support condition was consistent with the theoretical calculation condition. The experimental results of actual bridges proved that the proposed method in this paper is feasible and effectiveness.

The field of three-dimensional (3D) printing has witnessed significant advancements in recent years, and its potential for revolutionizing medical applications is rapidly emerging. This review aims to provide an overview of the current state and scope of 3D printing in the medical field. The review begins by highlighting the various 3D printing technologies currently employed in healthcare settings, including stereolithography, selective laser sintering, fused deposition modeling, and inkjet printing. Each technology's advantages and limitations are discussed, shedding light on their suitability for different medical applications. Next, the review delves into the diverse range of medical applications where 3D printing has shown promise. These applications include the fabrication of patient-specific anatomical models for preoperative planning, surgical guides and tools, customized implants and prosthetics, tissue engineering scaffolds, and drug delivery systems. The potential benefits of using 3D printing in these areas, such as enhanced surgical accuracy, improved patient outcomes, reduced surgery time, and personalized medicine, are explored. Furthermore, the review addresses the challenges and limitations associated with implementing 3D printing in medical settings. These challenges include regulatory concerns, standardization of processes, material biocompatibility, cost-effectiveness, and scalability. The ongoing efforts to overcome these barriers and the future directions of 3D printing in medicine are also discussed. In conclusion, 3D printing holds immense potential for transforming various aspects of medical practice. While considerable progress has been made, there are still challenges to be addressed before widespread adoption can be achieved. With continued research and development, coupled with regulatory support and collaboration between academia, industry, and healthcare professionals, 3D printing is poised to International Journal of Scientific Research in Engineering and Management (IJSREM) Volume: 07 Issue: 07 | July - 2023 SJIF Rating: 8.176 ISSN: 2582-3930 © 2023, IJSREM | www.ijsrem.com DOI: 10.55041/IJSREM24845 | Page 2 make a substantial impact in the field of medicine, improving patient care and treatment outcomes. Key words: Additive manufacturing (AM); Bio-medical; Fused Deposition Modelling (FDM); Selective Laser Sintering (SLS); Stereolithography (SLA); Digital Light Processing (DLP); Binder Jetting; Material Jetting; Direct Energy Deposition (DED).

Three dimensional (3D) printing as an advanced manufacturing technology is progressing to be established in the pharmaceutical industry to overcome the traditional manufacturing regime of 'one size fits for all'. Using 3D printing, it is possible to design and develop complex dosage forms that can be suitable for tuning drug release. Polymers are the key materials that are necessary for 3D printing. Among all 3D printing processes, extrusion-based (both fused deposition modeling (FDM) and pressure-assisted microsyringe (PAM)) 3D printing is well researched for pharmaceutical manufacturing. It is important to understand which polymers are suitable for extrusion-based 3D printing of pharmaceuticals and how their properties, as well as the behavior of polymer–active pharmaceutical ingredient (API) combinations, impact the printing process. Especially, understanding the rheology of the polymer and API–polymer mixtures is necessary for successful 3D printing of dosage forms or printed structures. This review has summarized a holistic materials–process perspective for polymers on extrusion-based 3D printing. The main focus herein will be both FDM and PAM 3D printing processes. It elaborates the discussion on the comparison of 3D printing with the traditional direct compression process, the necessity of rheology, and the characterization techniques required for the printed structure, drug, and excipients. The current technological challenges, regulatory aspects, and the direction toward which the technology is moving, especially for personalized pharmaceuticals and multi-drug printing, are also briefly discussed.

Estimation of modal parameters of a beam under random excitation using a novel 3D continuously scanning laser Doppler vibrometer system and an extended demodulation method

Three-dimensional (3D) printing has long been used in the manufacturing sector as a way to automate, accelerate production and reduce waste materials. By using this technology, it is possible to build a wide variety of objects if the necessary specifications are provided to the printer and no problems are presented by the limited range of materials available. With 3D printing becoming cheaper, more reliable and, as a result, more prevalent in the world at large, it may soon make inroads into the construction industry. Little is known, however, of 3D printing in current use in the construction industry and its potential for the future, and this paper seeks to investigate this situation by providing a review of the relevant literature. In doing this, the three main 3D printing methods of contour crafting, concrete printing and D-shape 3D printing are described, which, as opposed to the traditional construction method of cutting materials down to size, deliver only what is needed for completion, vastly reducing waste. The paper also identifies 3D printing's potential to enable buildings to be constructed many times faster and with significantly reduced labour costs. In addition, it is clear that construction 3D printing can allow the further inclusion of building information modelling into the construction process, thus streamlining and improving the scheduling requirements of a project. However, the current 3D printing processes are known to be costly, unsuited to large-scale products and conventional design approaches and have a very limited range of materials that can be used. Moreover, the only successful examples of construction in action to date have occurred in controlled laboratory environments and, as real world trials have yet to be completed, it is yet to be seen whether it can be equally proficient in practical situations.

Graphene is an important nanocarbon nanofiller for polymeric matrices. The polymer–graphene nanocomposites, obtained through facile fabrication methods, possess significant electrical–thermal–mechanical and physical properties for technical purposes. To overcome challenges of polymer–graphene nanocomposite processing and high performance, advanced fabrication strategies have been applied to design the next-generation materials–devices. This revolutionary review basically offers a fundamental sketch of graphene, polymer–graphene nanocomposite and three-dimensional (3D) and four-dimensional (4D) printing techniques. The main focus of the article is to portray the impact of 3D and 4D printing techniques in the field of polymer–graphene nanocomposites. Polymeric matrices, such as polyamide, polycaprolactone, polyethylene, poly(lactic acid), etc. with graphene, have been processed using 3D or 4D printing technologies. The 3D and 4D printing employ various cutting-edge processes and offer engineering opportunities to meet the manufacturing demands of the nanomaterials. The 3D printing methods used for graphene nanocomposites include direct ink writing, selective laser sintering, stereolithography, fused deposition modeling and other approaches. Thermally stable poly(lactic acid)–graphene oxide nanocomposites have been processed using a direct ink printing technique. The 3D-printed poly(methyl methacrylate)–graphene have been printed using stereolithography and additive manufacturing techniques. The printed poly(methyl methacrylate)–graphene nanocomposites revealed enhanced morphological, mechanical and biological properties. The polyethylene–graphene nanocomposites processed by fused diffusion modeling have superior thermal conductivity, strength, modulus and radiation- shielding features. The poly(lactic acid)–graphene nanocomposites have been processed using a number of 3D printing approaches, including fused deposition modeling, stereolithography, etc., resulting in unique honeycomb morphology, high surface temperature, surface resistivity, glass transition temperature and linear thermal coefficient. The 4D printing has been applied on acrylonitrile-butadiene-styrene, poly(lactic acid) and thermosetting matrices with graphene nanofiller. Stereolithography-based 4D-printed polymer–graphene nanomaterials have revealed complex shape-changing nanostructures having high resolution. These materials have high temperature stability and high performance for technical applications. Consequently, the 3D- or 4D-printed polymer–graphene nanocomposites revealed technical applications in high temperature relevance, photovoltaics, sensing, energy storage and other technical fields. In short, this paper has reviewed the background of 3D and 4D printing, graphene-based nanocomposite fabrication using 3D–4D printing, development in printing technologies and applications of 3D–4D printing.

Three-dimensional (3D) printing is a new rapid additive method to make 3D objects with exact shapes and structures. 3D printing is being used for a variety of applications, including automotive, medical, dental, aerospace, consumer goods, toys, novelty items, embedded electronics and appliances. The goal of this work was to investigate the smoothness, precision and topography of plastic materials that can be used for three-dimensional printing applications. These three performance characteristics are crucial to performance of any 3D printed product. Fused Deposition Modeling (FDM) and PolyJet™ technology were used to produce 3D printed shapes for testing these performance measures for the different processes. Three samples of acrylonitrile butadiene styrene (ABS) were printed utilizing different numbers of layers. That is, one, two and three layers at a 45o (head angle) were printed. The angle is related to the direction of the printing, which is controlled automatically by MakerWare software of the 3D printer itself, without any external control from the operator or technician. Thickness and roughness for each sample were subsequently measured. One sample of polylactic acid (PLA) was printed with one layer at 45o and its thickness and roughness were also measured. Two other samples of ABS, having one and two layers, were printed at 90o then thickness and smoothness were measured. Polyvinyl alcohol (PVA) was printed with one layer at 45° and 90o. Digital ABS™ was printed at 6 different layer thicknesses. Thickness and roughness of printed 3D samples were measured using a White Light Interferometer. The results show that the roughness of ABS at 45° and 90° increased with increasing thickness. The samples printed at 90° were smoother than at 45°, which means the orientation had a significant influence on roughness, but little on thickness. We found that the minimum thickness that MakerBot can reach is 50 µm, while with FlashForge it is 80 µm. The samples that were printed by Stratasys 500 Objet Connex3 were smoother than those printed by MakerBot replicator 2X and FlashForge Creator Pro. Also, Stratasys 500 Objet Connex3 is more precise than either and it can reach thinner levels than either of them. However, the highest performance printer does not produce sufficient precision and smoothness for most 3D printing applications.

To reduce the carbon footprint of manufacturing processes, it is necessary to reduce the number of stages in the development process. To this end, integrating additive manufacturing processes with three-dimensional (3D) printing makes it possible to eliminate the need to use tooling for component manufacturing. Furthermore, using 3D printing allows the generation of complex models to optimize different components, reducing the development time and realizing lightweight structures that can be applied in different industries, such as the mobility industry. Printing process parameters have been studied to improve the mechanical properties of printed items. In this regard, although the failure of most structural components occurs under dynamic load, the majority of the evaluations are quasistatic. This work highlights an improvement in fatigue strength under dynamic loads in 3D-printed components through heat treatment. The fatigue resistance was improved regarding the number of cycles and the dispersion of results. This allows 3D-printed polylactic acid components to be structurally used, and increasing their reliability allows their evolution from a prototype to a functional component.

Telemedicine is defined as the delivery of healthcare services at a distance using electronic means. The incorporation of 3D printing in the telemedicine cycle could result in pharmacists designing and manufacturing personalised medicines based on the electronic prescription received. Even with the advantages of telemedicine, numerous barriers to the uptake hinder the wider uptake. Of particular concern is the cyber risk associated with the remote digital transfer of the computer-aided design (CAD) file (acting as the electronic prescription) to the 3D printer and the reproducibility of the resultant printed medicinal products. This proof-of-concept study aimed to explore the application of secure remote 3D printing of model solid dosage forms using the patented technology, DEFEND3D, which is designed to enhance cybersecurity and intellectual property (IP) protection. The size, shape, and colour of the remote 3D-printed model medicinal products were also evaluated to ensure the end-product quality was user-focused. Thermoplastic polyurethane (TPU) and poly(lactic) acid (PLA) were chosen as model polymers due to their flexibility in preventing breakage printing and ease of printing with fused deposition modelling (FDM). Our work confirmed the potential of secure remote 3D (FDM) printing of prototype solid dosage forms resulting in products with good reproducibility, resolution, and quality towards advancements in telemedicine and digital pharmacies. The limitation of the work presented here was the use of model polymers and not pharmaceutically relevant polymers. Further work could be conducted using the same designs chosen in this study with pharmaceutically relevant polymers used in hot-melt extrusion (HME) with shown suitability for FDM 3D printing. However, it should be noted that any challenges that may occur with pharmaceutically relevant polymers are likely to be related to the polymer’s printability and printer choice as opposed to the ability of the CAD file to be transferred to the printer remotely.

PurposeThis paper aims to provide a review of four-dimensional (4D) printing using fused-deposition modeling (FDM). 4D printing is an emerging innovation in (three-dimensional) 3D printing that encompasses active materials in the printing process to create not only a 3D object but also a 3D object that can perform an active function. FDM is the most accessible form of 3D printing. By providing a review of 4D printing with FDM, this paper has the potential in educating the many FDM 3D printers in an additional capability with 4D printing.Design/methodology/approachThis is a review paper. The approach was to search for and review peer-reviewed papers and works concerning 4D printing using FDM. With this discussion of the shape memory effect, shape memory polymers and FDM were also made.Findings4D printing has become a burgeoning area in addivitive manufacturing research with many papers being produced within the past 3-5 years. This is especially true for 4D printing using FDM. The key findings from this review show the materials and material composites used for 4D printing with FDM and the limitations with 4D printing with FDM.Research limitations/implicationsLimitations to this paper are with the availability of papers for review. 4D printing is an emerging area of additive manufacturing research. While FDM is a predominant method of 3D printing, it is not a predominant method for 4D printing. This is because of the limitations of FDM, which can only print with thermoplastics. With the popularity of FDM and the emergence of 4D printing, however, this review paper will provide key resources for reference for users that may be interested in 4D printing and have access to a FDM printer.Practical implicationsPractically, FDM is the most popular method for 3D printing. Review of 4D printing using FDM will provide a necessary resource for FDM 3D printing users and researchers with a potential avenue for design, printing, training and actuation of active parts and mechanisms.Social implicationsContinuing with the popularity of FDM among 3D printing methods, a review paper like this can provide an initial and simple step into 4D printing for researchers. From continued research, the potential to engage general audiences becomes more likely, especially a general audience that has FDM printers. An increase in 4D printing could potentially lead to more designs and applications of 4D printed devices in impactful fields, such as biomedical, aerospace and sustainable engineering. Overall, the change and inclusion of technology from 4D printing could have a potential social impact that encourages the design and manufacture of such devices and the treatment of said devices to the public.Originality/valueThere are other 4D printing review papers available, but this paper is the only one that focuses specifically on FDM. Other review papers provide brief commentary on the different processes of 4D printing including FDM. With the specialization of 4D printing using FDM, a more in-depth commentary results in this paper. This will provide many FDM 3D printing users with additional knowledge that can spur more creative research in 4D printing. Further, this paper can provide the impetus for the practical use of 4D printing in more general and educational settings.

As the importance of visual aids increases, textbooks are including more figures and images to help with students' understanding. These visual aids enable students to learn concepts more effectively by hearing and seeing them simultaneously. However, for students who are visually impaired (that is, blind or have low vision), reading and understanding a textbook poses challenges. Teachers of students who are visually impaired have difficulty teaching with textbooks because they are compelled to explain and describe the complex figures and content verbally. Even after being explained, the image or concept might still remain nebulous for the student. Therefore, to help both students and their teachers, instructional materials should be prepared with easy, cheap, and customizable methods such as three-dimensional (3D) printing. Instead of seeing and hearing, students can use their sense of touch to recognize the 3D tactile aids, which might improve their learning and memory processes. Recently, 3D printing technology has emerged as an exciting technological tool for creating sophisticated and custom-made objects with relatively low-cost materials (Melchels, Feijen, & Grijpma, 2010; Peltola, Melchels, Grijpma, & Kellomaki, 2008; Pham & Gault, 1998). 3D printing is the process of fabricating 3D objects by building up materials layer by layer with a specific layer thickness in the range of 100 to 400 micrometers (^m). The most important advantage of 3D printing is its ability to build new objects in a customized way. Thus, 3D printing can be a powerful tool to make tactile patterns or objects related to textbooks. Stangl et al. tried to make 3D-printed picture books for visually impaired children (Stangl, Kim, & Yeh, 2014). They transcribed the images of the classic book Goodnight Moon, by Margaret Wise Brown, by printing features with different plastic layers. However, this study presented only plane-based shapes and not complete 3D objects. In this research, we investigate how 3D printing technology could be utilized for instructional materials that allow visually impaired students to have full access to high-quality instruction in history class. Researchers from the 3D Printing Group of the Korea Institute of Science and Technology (KIST) provided the Seoul National School for the Blind with tactile instructional materials and resizable braille made by 3D printers as shown in Figure 1. The teacher provided side-by-side hands-on instruction to guide students in understanding the characteristics of the shapes and their meanings. Students also used their hands to independently explore the 3D materials, allowing them to appropriately feel the historical pictures, maps, or relics. This procedure reinforced delivery of the lecture immensely since it clarified potential misunderstanding of text descriptions. The resulting implication was that the 3D instructional materials were beneficial and more suitable to help visually impaired students successfully comprehend content taught in the classroom. METHODS Three different types of 3D printing methods were utilized: (1) fused deposition modeling (FDM); (2) three-dimensional printing (3DP); and (3) digital light processing (DLP). The 3D printing process involves multiple stages, as shown in Figure 2. All 3D printing techniques are based on the use of computer-aided design (CAD) information that describes the geometry and size of the objects to be printed. The CAD data is converted to an STL (STereoLithography) file format which has extensive triangular coordination of 3D surface geometry (Chen, Ng, & Wang, 1999). Once the file is in a printable format, the 3D model is sliced into a series of digital crosssectional layers of specific thickness. Then the designed structure is built through a layerby-layer fabrication process with each layer thickness being 100 |m. When the printing is completed, the last step involves post-treatment operations to the object to improve its softness, durability, and safety. …

Three-dimensional (3D) printing has showed great potential for the construction of electrochemical sensor devices. However, reported 3D-printed biosensors areusually constructed by physical adsorption and needed immobilizing reagents on the surface of functional materials. To construct the 3D-printed biosensors, the simple modification of the 3D-printed device by non-expert is mandatory to take advantage of the remote, distributed 3D printing manufacturing. Here, a 3D-printed electrode was prepared by fused deposition modeling (FDM) 3D printing technique and activated by chemical and electrochemical methods. A glucose oxidase-based 3D-printed nanocarbon electrode was prepared by covalent linkage method to an enzyme on the surface of the 3D-printed electrode to enable biosensing. X-ray photoelectron spectroscopy and scanning electron microscopy were used to characterize the glucose oxidase-based biosensor. Direct electrochemistry glucose oxidase-based biosensor with higher stability was then chosen to detect the two biomarkers, hydrogen peroxide and glucose by chronoamperometry. The prepared glucose oxidase-based biosensor was further used for the detection of glucose in samples of apple cider. The covalently linked glucose oxidase 3D-printed nanocarbon electrode as a biosensor showed excellent stability. This work can open new doors for the covalent modification of 3D-printed electrodes in other electrochemistry fields such as biosensors, energy, and biocatalysis.