Dimensional Printing Research Articles

Multimaterial Embedded 3D Printing of Composite Reinforced Soft Actuators.

Soft pneumatic actuators (SPAs) have attracted enormous attention in the growing field of robotics. Among different SPAs, composite reinforced actuators (CRAs) are widely used because of their simple structure and high controllability. However, multistep molding, a time-consuming method, is still the predominant fabrication method. Here, we propose a multimaterial embedded printing method (ME3P) to fabricate CRAs. In comparison with other 3-dimensional printing methods, our method improves fabrication flexibility greatly. Via the design and fabrication of the reinforced composites' patterns and different geometries of the soft body, we demonstrate actuators with programmable responses (elongation, contraction, twisting, bending, and helical and omnidirectional bending). Finite element analysis is employed for the prediction of pneumatic responses and the inverse design of actuators based on specific actuation needs. Lastly, we use tube-crawling robots as a model system to demonstrate our ability to fabricate complex soft robots for practical applications. This work demonstrates the versatility of ME3P for the future manufacturing of CRA-based soft robots.

Experimental analysis of 3D printed specimens with different printing parameters for Izod impact strength

Three dimensional printing process which helps rapid design and manufacture of complex component using computer aided design models is called Additive manufacturing (AM). The properties of fused deposition modelling components depend on the printing parameter. The objective of the paper is to experimentally evaluate the Izod impact property of 3D printed test specimens. The test specimen are printed using a commercial 3D printer. Considering different printing parameters like infill density, printing orientation and pattern, Izod impact strength of the test specimens was analyzed. The specimen was designed with infill density ranging from 20% to 100% and four infill pattern are grid, rectilinear, honeycomb, cubic and three printing orientation which is edge, vertical, flat. The specimens were printed using two types of filament ABS and ASA. The specimen is prepared according to ASTM D256 type E with shrinkage allowance. The study concluded that the Izod impact strength of the specimen manufactured with the ABS has more strength than ASA.

3D Printing Basic Knowledge and Skills Training for Teachers of SMAN 2 Palopo

3-Dimensional printing is a manufacturing technique used to create 3-dimensional products. The tool used is a 3D printer with constituent materials such as plastic, metal and powder. This community service activity uses a 3D printer made from plastic because it is considered more practical and effective for laboratory scale. The training participants were teachers at SMAN 2 Palopo, with the presenters being lecturers at Cokroaminoto University, Palopo. The aim of this community service activity is to introduce and provide training to SMAN 2 Palopo teachers in using 3D printer machines. The training participants provided basic material: using a 3D printer machine, how to install the tool, create a design, transfer the design file to the printer, and so on printing the 3D design. The evaluation process is grouped into four categories, namely understanding the concept, installation and use, machine maintenance and desire for further study. Participants' understanding increased by 1.7 points after attending the training. In the skills of installing and using and maintaining machines, the participants' pretest scores were quite low (1.8 and 2.1 points respectively) and increased quite sharply by 2.5 and 2.1 points after training. Meanwhile, the pretest score for wanting to know 3D printing technology reached 3.4 points and increased after participating in the training to 4.5 points. The evaluation results show that 3D printing technology is not yet well known by the public, especially educational institutions. With this existing training, it is hoped that teachers at SMAN 2 Palopo will be able to know and master 3D printing technology which was developed according to their respective knowledge. Furthermore, these skills can be taught to students through seminars, extracurricular activities or can be included in curricular learning materials.

USE OF THREE DIMENSIONAL (3D) PRINTED MODELS OF SHEEP BRAIN IN ONLINE VETERINARY ANATOMY EDUCATION

Three dimensional (3D) printing technology in veterinary anatomy education is an evolving area providing accurately, rapidly, and reproducibly anatomical specimens. In this study, 3D printed sheep brain models were produced using magnetic resonance imaging (MRI) scanning, and their effectiveness was compared with cadaveric materials by creating three groups from undergraduate veterinary students. The study was performed when veterinary anatomy lectures in Erciyes University were carried out via live fully online learning platforms in virtual classes like many other universities in the world due the Covid-19 pandemic. Participants were subjected to an approximately 30 minute online lecture on the external and internal anatomy of the sheep brain using cadaveric materials only (n=21, Group 1), 3D printed models only (n=20, Group 2), or a combination of cadaveric materials and 3D printed models (n=20, Group 3) as teaching aids. Online post-tests carried out following the online lectures showed no statistically significant difference between the scores of the groups. Furthermore, online questionnaires conducted after the post-tests demonstrated that 3D printed models helped students learn about sheep brain anatomy. The finding of this study suggests that 3D printed models can be considered as a supplement teaching resource to cadaveric materials in veterinary anatomy education particularly when students are supposed to learn more in a limited time regardless of whether or not the Covid-19 pandemic might end.

Development of a Pedicle Screw Fixation Simulation Model for Surgical Training Using a 3-Dimensional Printer

Training surgeons in pedicle screw fixation (PSF) techniques during actual surgery is limited because of patient safety, complications, and surgical efficiency issues. Recent technical developments are leading the world to an era of personalized three-dimensional (3D) printing. This study aimed to evaluate the educational effect of using a 3D-printed spine model to train beginners in PSF techniques to improve screw accuracy and procedure time. Computed tomography (CT) scan data were used in a 3D printer to produce a life-size lumbar spine replica of L1-3 vertebrae. Four residents performed PSF thrice. Each resident performed 18 screw fixations on both sides (6 screws per trial). The time to complete the procedure and pedicle violation was recorded. The average time for the 3 procedures was 42.1±2.9 minutes, 38.8±3.3 minutes, and 32.1±2.5 minutes, respectively. Furthermore, the average pedicle screw score for the 3 procedures was 13.0±0.8, 14.5±0.6, and 16.0±0.8, respectively. As the trial was repeated, the procedure time decreased and the accuracy of screw fixation tended to be more accurate. It was possible to decrease the procedure time and increase accuracy through repeated training using the 3D-printed spine model. By implementing a 3Dprinted spine model based on the patient's actual CT data, surgeons can perform simulation surgery before the actual surgery. Therefore, this technology can be useful in educating residents to improve their surgical skills.

Preliminary Application Research of 3D Bioprinting in Craniofacial Reconstruction.

In recent years, 3-dimensional (3D) printing has been widely used in regenerative medicine research and other fields because of its ability to customize macroscopic morphology and precisely control microstructure. Polymer scaffolds are 1 of the commonly used 3D bioprinting materials for defect repair and have recently been a research focus. Our article explored the bone-formation accelerating effect of 3D-printed porous scaffold Poly(glycerol sebacate) [PGS] in the critical bone defect of an enhancing rabbit mandibular model. Also, we overview and summarize the classification of 3D bioprinting materials and prospects for their various application scenarios in craniofacial reconstruction surgery. A PGS elastomer scaffold was prepared by polymerizing equimolar amounts of sebacic acid and glycerol using a biological 3D printer. Six male New Zealand white rabbits were prepared (3 for the control group and 3 for the PGS group), each weighing 3kg. Osteotomy was performed at the anterior edge of the ascending ramus of the mandible with a bone saw to open the 8mm defect. Defects of the control group were empty, and defects of the PGS group were put into 8mm-wide PGS elastomer scaffolds. The rabbits were euthanized 6 weeks after the operation, and the postoperative mandibles were collected. Information (presence or absence of pus from infection, nonunion, degree of macroscopic bone healing) was recorded, and the skeletal tissue was fixed in a paraformaldehyde solution. The mandible on the enhanced side was significantly longer than that on the opposite side, and the contralateral incisor was hyperplasia. The mandibles of rabbits in each group healed well, and there was no obvious local infection and purulence. The gross specimen appearance showed that both ends of the defect were connected. When comparing the reconstructed mandibles of the two groups, it is apparent that the width and thickness of the new bone in the PGS group were significantly better than that in the control group. This article verifies the effect of 3D polypore PGS scaffolds in animal craniomaxillofacial bone defects and introduces various application scenarios of 3D printing materials in craniomaxillofacial reconstruction surgery. There are quite good application prospects for 3D bioprinting in animal experiments and even clinical treatment of craniofacial defects.

A voxel-by-voxel method for mixing two filaments during a 3D printing process for soft-tissue replication in an anthropomorphic breast phantom

Objective. In this study, a novel voxel-by-voxel mixing method is presented, according to which two filaments of different material are combined during the three dimensional (3D) printing process. Approach. In our approach, two types of filaments were used for the replication of soft-tissues, a polylactic acid (PLA) filament and a polypropylene (PP) filament. A custom-made software was used, while a series of breast patient CT scan images were directly associated to the 3D printing process. Each phantom´s layer was printed twice, once with the PLA filament and a second time with the PP filament. For each material, the filament extrusion rate was controlled voxel-by-voxel and was based on the Hounsfield units (HU) of the imported CT images. The phantom was scanned at clinical CT, breast tomosynthesis and micro CT facilities, as the major processing was performed on data from the CT. A side by side comparison between patient´s and phantom´s CT slices by means of profile and histogram comparison was accomplished. Further, in case of profile comparison, the Pearson´s coefficients were calculated. Main results. The visual assessment of the distribution of the glandular tissue in the CT slices of the printed breast anatomy showed high degree of radiological similarity to the corresponding patient´s glandular distribution. The profile plots´ comparison showed that the HU of the replicated and original patient soft tissues match adequately. In overall, the Pearson´s coefficients were above 0.91, suggesting a close match of the CT images of the phantom with those of the patient. The overall HU were close in terms of HU ranges. The HU mean, median and standard deviation of the original and the phantom CT slices were −149, −167, ±65 and −121, −130, ±91, respectively. Significance. The results suggest that the proposed methodology is appropriate for manufacturing of anthropomorphic soft tissue phantoms for x-ray imaging and dosimetry purposes, since it may offer an accurate replication of these tissues.

Three-dimensional printing template for intraoperative localization of pulmonary nodules in the pleural cavity.

Localization of pulmonary nodules is challenging. However, traditional localization methods have high radiation doses and a high risk of complications. We developed a noninvasive 3-dimensional printing navigational template for intraoperative localization. It can reduce puncture-related complications and simplify the localization process. This study will verify the feasibility of this method. Patients with peripheral pulmonary nodules were included in this study. The computed tomography scan sequences were obtained to design a digital template model, which was then imported into a 3-dimensional printer to produce a physical navigational template. Finally, the navigational template is placed into the patient's pleural cavity for intraoperative localization. The precision of the nodule localization and associated complications were evaluated. Twelve patients were finally included in this study. Intraoperative navigational template localization was used in all patients. The success rate of intraoperative nodule localization was 100%, and the median time of localization was 19.5minutes (range, 16-23.5minutes). The deviation median of the navigational template was 2.1mm (range, 1.1-2.7mm). Among the included patients, no significant complications occurred during intraoperative localization. The 3-dimensional printing template for intraoperative localization is feasible, will cause no trauma to the patient, and has acceptable accuracy for application in nodules localization. This navigational template greatly simplifies the localization process and may potentially break the dependence of percutaneouslocalization on computed tomography scanning.

A digital workflow for fabricating an interim obturator after partial maxillary resection

This article describes a digital workflow for fabricating an interim obturator after partial maxillectomy which utilizes the radiopacity of iodoform gauze, a common surgical packing material, to simulate postoperative oronasal defect cavities through a computer-aided design and computer-aided manufacturing (CAD-CAM) workflow and to generate the interim obturator by 3-dimensional printing. This technique may serve as a promising alternative technique for the fabrication of an interim obturator and, in particular, benefit patients who have not seen a prosthetic specialist before surgery and present without a surgical obturator.

Trueness and precision of artificial teeth in CAD-CAM milled complete dentures from custom disks with a milled recess

Statement of problemStudies on the movement of artificial teeth during the manufacturing of computer-aided design and computer-aided manufacturing (CAD-CAM) complete dentures using the custom disk method with milled recesses and on whether the movement is within a clinically acceptable range are lacking. PurposeThe purpose of this in vitro study was to assess the trueness and precision of the artificial teeth on custom disks the recesses of which were manufactured using a milling machine and to compare the results with the recesses manufactured using a 3-dimensional (3D) printer. Material and methodsFour types of artificial teeth (maxillary left central incisors [Max-L1], mandibular left central incisors [Man-L1], maxillary left first premolars [Max-L4], and maxillary left first molars [Max-L6]) were prepared. Milling data were created, and 3 of each type of tooth were attached to each disk made up of 3 concentric circles (large, medium, and small). Five each of the 3D-printed custom disks and custom disks with milled recesses were milled based on the milling data. Standard tessellation language data were obtained through cone beam computed tomography and superimposed by using a CAD software program. Mean absolute error (MAE) values were calculated to assess trueness and precision; MAE values of artificial teeth in custom disks with milled recesses and 3D-printed custom disks were statistically compared by using the 2-way analysis of variance test with 2 factors, 2 types of custom disks and 4 types of artificial teeth, and the Tukey post hoc comparison (α=.05). ResultsRegarding position trueness, the MAE value of Man-L1 on the milling custom disk was significantly lower than that of the 3D-printed custom disk (P<.001), whereas the MAE values of Max-L4 and Max-L6 on the milling custom disk were significantly higher than those on the 3D-printed custom disk (P<.001). No significant difference was found in the MAE value of the position trueness of Max-L1 between the milling and 3D-printed custom disks. Regarding position precision, the MAE values of Max-L1, Man-L1, and Max-L4 on the milling custom disk were significantly lower than those on the 3D-printed custom disks (P=.002, P<.001, P=.025, respectively). However, no significant difference was seen in the MAE value of position precision of Max-L6 between the milling and 3D-printed custom disks (P=.180) ConclusionsMovement of artificial teeth during the manufacture of dentures using the custom disk method and custom disks with milled recesses was within a clinically acceptable range.

Comparison of 2 open-sourced 3-dimensional modeling techniques for orthopaedic application.

Objectives: Although 3-dimensional (3D) printing is becoming more widely adopted for clinical applications, it is yet to be accepted as part of standard practice. One of the key applications of this technology is orthopaedic surgical planning for urgent trauma cases. Anatomically accurate replicas of patients' fracture models can be produced to guide intervention. These high-quality models facilitate the design and printing of patient-specific implants and surgical devices. Therefore, a fast and accurate workflow will help orthopaedic surgeons to generate high-quality 3D printable models of complex fractures. Currently, there is a lack of access to an uncomplicated and inexpensive workflow. Methods: Using patient DICOM data sets (n = 13), we devised a novel, simple, open-source, and rapid modeling process using Drishti software and compared its efficacy and data storage with the 3D Slicer image computing platform. We imported the computed tomography image directory acquired from patients into the software to isolate the model of bone surface from surrounding soft tissue using the minimum functions. One pelvic fracture case was further integrated into the customized implant design practice to demonstrate the compatibility of the 3D models generated from Drishti. Results: The data sizes of the generated 3D models and the processing files that represent the original DICOM of Drishti are on average 27% and 12% smaller than that of 3D Slicer, respectively (both P < 0.05). The time frame needed to reach the stage of viewing the 3D bone model and the exporting of the data of Drishti is 39% and 38% faster than that of 3D Slicer, respectively (both P < 0.05). We also constructed a virtual model using third-party software to trial the implant design. Conclusions: Drishti is more suitable for urgent trauma cases that require fast and efficient 3D bone reconstruction with less hardware requirement. 3D Slicer performs better at quantitative preoperative planning and multilayer segmentation. Both software platforms are compatible with third-party programs used to produce customized implants that could be useful for surgical training. Level of Evidence: Level V.

Digital workflow for low-cost 3D-printed custom healing abutment based on emergence profile CBCT segmentation

Several protocols have been used with computer-aided design and computer-aided manufacture (CAD-CAM) prostheses after image-guided implant surgery based on a prosthetically driven surgical plan. For delayed approaches, a CAD-CAM custom healing abutment can be manufactured before the surgery and installed immediately after implant placement. However, information on the use of emergence profile segmentation on which to base the digital design and on the use of low-cost 3-dimensional printers to produce custom healing abutments are lacking. The purpose of this article was to present a fully digital workflow to digitally design and 3-dimensionally print custom healing abutments with a biocompatible light-polymerizing resin based on the natural emergence profile of the tooth to be replaced.

REPLY FROM AUTHORS: Septal myectomy performed along the "septal band".

We appreciate the insightful comments on our paper from Dr Andrushchuk and his colleagues.1 First and foremost, we admire their pioneering work on the introduction of 3-dimensional printing technology in septal myectomy.

3D printed cylindrical capsules as a Chlorella pyrenoidosa immobilization device for removal of lead ions contamination.

Immobilization is considered as a promising strategy toward the practical applications of powdered adsorbent. Herein, three dimensional (3D) printing cylindrical capsules with cross-linked PVA hydrogels membrane in encapsulate Chlorella pyrenoidosa (Cp) were utilized for removal of lead ions. The chemical compositions, hydrogels performance and morphologies of the membranes were determined by Fourier transformed infrared spectroscopy (FTIR), cross-linking degree, swelling degree, membrane flux and scanning electron microscopy (SEM). It is found that PVA cross-linking structure is successfully synthesized on the surface of capsule body and cap due to the presence of PVA in the filament. The lead ions adsorption capacity related to initial concentration of 50mg/L in 48h is reached 75.61%, revealing a good removal ability. The self-floating 3D printed capsules device also shows an excellent recovering property. After 7 runs of adsorption experiment, the lead ions adsorption ratio remains 78.56%, which will bring a broad prospect in wastewater treatment, chemical slow release along with sample preparation and separation.

Three-dimensional Printing Technologies in Craniofacial Plastic Surgery: An Institutional Experience.

Rapid developments in 3-dimensional(3D) printing technologies in craniofacial plastic surgery have provided a new treatment modality for patients. In this article, we intend to share our institution's experience using 3D printing in 3 modes-namely, 3-dimensional printing for manufacturing contour models, guides, and implants. Fifty-nine patients were enrolled in our study between September 2009 and September 2021. Among the 3D printing-assisted technologies, 41 cases were used for congenital malformations, 82 for trauma repair, and 112 for cosmetic surgery. Preoperative design and postoperative data were compared and analyzed based on imaging data. In craniofacial plastic surgery, all patients had excellent postoperative objective bone measurements close to the preoperative design and improved esthetic appearance. Our survey of postoperative satisfaction showed that patients were quite satisfied with the surgery, especially concerning congenital deformities. Rapid prototyping 3-dimensional printing technology provides a practical and anatomically accurate means to produce patient-specific and disease-specific translational tools. These models can be used for surgical planning, simulation, and clinical evaluation. Expanding this technology in craniofacial plastic surgery will provide adequate assistance to practitioners and patients.

Extrusion 3D printing of minicaplets for evaluating in vitro &in vivo praziquantel delivery capability

This study aimed to explore extrusion three dimensional (3D) printing technology to develop praziquantel (PZQ)-loaded minicaplets and evaluate their in vitro and in vivo delivery capabilities. PZQ-loaded minicaplets were 3D printed using a fused deposition modelling (FDM) principle-based extrusion 3D printer and were further characterized by different in vitro physicochemical and sophisticated analytical techniques. In addition, the % PZQ entrapment and in vitro PZQ release performance were evaluated using chromatographic techniques. It was in vitro observed that PZQ was fully released in the gastric pH medium within the period of gastric emptying, that is, 120 min, from the PZQ-loaded 3D printed minicaplets. Furthermore, in vivo pharmacokinetic (PK) profiles of PZQ-loaded 3D printed minicaplets were systematically evaluated using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The PK profile of the PZQ-loaded 3D printed minicaplets was established using different parameters such as Cmax, Tmax, AUC0-t, AUC0-∞, and oral relative bioavailability (RBA). The Cmax value of pristine PZQ was found at 64.79 ± 13.99 ng/ml, while PZQ-loaded 3D printed minicaplets showed a Cmax of 263.16 ± 47.85 ng/ml. Finally, the PZQ-loaded 3D printed minicaplets showed 9.0-fold improved oral RBA compared with that of pristine PZQ (1.0-fold). Together, these observations potentiate the desired in vitro and improved in vivo delivery capabilities of PZQ from the PZQ-loaded 3D printed minicaplets.

Application of 3D printing technology combined with PBL teaching method in clinical teaching of cerebrovascular disease: An observational study

Traditional clinical teaching does not allow medical students to combine theoretical knowledge with practical knowledge. As such, we aimed to determine the effectiveness of three dimensional (3D) printing technology combined with problem-based learning (PBL) in the clinical teaching of cerebrovascular diseases. Medical interns were randomly divided into an experimental group (n = 136) that was taught using 3D printing technology + PBL method and a control group (n = 133) that was taught using traditional methods. We compared assessment results of theoretical and clinical practice skills and the subjective evaluation of teaching methods between the 2 groups. The assessment results of the experimental group were significantly higher than those in the control group (P < .05). The survey assessing the evaluation of teaching methods showed higher satisfaction with teaching methods, increased learning interest, and improvement in the spatial thinking ability of interns in the experimental group compared to the control group (P < .05). There was no significant difference when assessing which teaching method better improved the interns' understanding of cerebrovascular diseases (P < .05). The application of 3D printing technology combined with the PBL teaching method in neurosurgery clinical teaching can stimulate interest in learning and significantly improve academic performance and problem-analysis and solving skills.

Effect of sterilization processes on alginate/gelatin inks for three-dimensional printing.

309Sterilization is a crucial step in the process of developing bioinks for tissue engineering applications. In this work, alginate/gelatin inks were subjected to three sterilization methods: ultraviolet (UV) radiation, filtration (FILT), and autoclaving (AUTO). In addition, to simulate the sterilization effect in a real environment, inks were formulated in two different media, specifically, Dulbecco's Modified Eagle's Medium (DMEM) and phosphate-buffered saline (PBS). First, rheological tests were performed to evaluate the flow properties of the inks, and we observed that UV samples showed shear thinning behavior, which was favorable for three-dimensional (3D) printing. Furthermore, the 3D-printed constructs developed with UV inks showed better shape and size fidelity than those obtained with FILT and AUTO. In order to relate this behavior to the material structure, Fourier transform infrared (FTIR) analysis was carried out and the predominant conformation in protein was determined by deconvolution of the amide I band, which confirmed that the prevalence of a-helix structure was greater for UV samples. This work highlights the relevance of sterilization processes, which are essential for biomedical applications, in the research field of bioinks.

Use of 3D anatomical models in mock circulatory loops for cardiac medical device testing.

Mock circulatory loops (MCLs) are mechanical representations of the cardiovascular system largely used to test the hemodynamic performance of cardiovascular medical devices (MD). Thanks to 3 dimensional (3D) printing technologies, MCLs can nowadays also incorporate anatomical models so to offer enhanced testing capabilities. The aim of this review is to provide an overview on MCLs and to discuss the recent developments of 3D anatomical models for cardiovascular MD testing. The review first analyses the different techniques to develop 3D anatomical models, in both rigid and compliant materials. In the second section, the state of the art of MCLs with 3D models is discussed, along with the testing of different MDs: implantable blood pumps, heart valves, and imaging techniques. For each class of MD, the MCL is analyzed in terms of: the cardiovascular model embedded, the 3D model implemented (the anatomy represented, the material used, and the activation method), and the testing applications. MCLs serve the purpose of testing cardiovascular MDs in different (patho-)physiological scenarios. The addition of 3D anatomical models enables more realistic connections of the MD with the implantation site and enhances the testing capabilities of the MCL. Current attempts focus on the development of personalized MCLs to test MDs in patient-specific hemodynamic and anatomical scenarios. The main limitation of MCLs is the impossibility to assess the impact of a MD in the long-term and at a biological level, for which animal experiments are still needed.

3D-Printed Fiber-Reinforced Polymer Composites by Fused Deposition Modelling (FDM): Fiber Length and Fiber Implementation Techniques.

Fused Deposition Modelling (FDM) is an actively growing additive manufacturing (AM) technology due to its ability to produce complex shapes in a short time. AM, also known as 3-dimensional printing (3DP), creates the desired shape by adding material, preferably by layering contoured layers on top of each other. The need for low cost, design flexibility and automated manufacturing processes in industry has triggered the development of FDM. However, the mechanical properties of FDM printed parts are still weaker compared to conventionally manufactured products. Numerous studies and research have already been carried out to improve the mechanical properties of FDM printed parts. Reinforce polymer matrix with fiber is one of the possible solutions. Furthermore, reinforcement can enhance the thermal and electrical properties of FDM printed parts. Various types of fibers and manufacturing methods can be adopted to reinforce the polymer matrix for different desired outcomes. This review emphasizes the fiber types and fiber insertion techniques of FDM 3D printed fiber reinforcement polymer composites. A brief overview of fused deposition modelling, polymer sintering and voids formation during FDM printing is provided, followed by the basis of fiber reinforced polymer composites, type of fibers (synthetic fibers vs. natural fibers, continuous vs. discontinuous fiber) and the composites' performance. In addition, three different manufacturing methods of fiber reinforced thermoplastics based on the timing and location of embedding the fibers, namely 'embedding before the printing process (M1)', 'embedding in the nozzle (M2)', and 'embedding on the component (M3)', are also briefly reviewed. The performance of the composites produced by three different methods were then discussed.