Search Results (143)

This article presents the results of the tribological performance of 20MnCr5 (1.7147) tool steel countersamples produced by Direct Metal Laser Sintering (DMLS), as a potential material for inserts or working layers of sheet metal forming tools. Tribological tests were performed using a roller-block tribotester. The samples were sheet metals made of materials with significantly different properties: Inconel 625, titanium-stabilised stainless steel 321, EN AW-6061 T0 aluminium alloy, and pure copper. The samples and countersamples were analysed in terms of their wear resistance, coefficient of friction (COF), changes in friction force during testing, and surface morphology after tribological contact under dry friction conditions. The tests were performed on DMLSed countersamples in the as-received state. The largest gain of countersample mass was observed for the 20MnCr5/EN AW-6061 T0 friction pair. The sample mass loss in this combination was also the largest, amounting to 19.96% of the initial mass. On the other hand, in the 20MnCr5/Inconel 625 friction pair, no significant changes in the mass of materials were recorded. For the Inconel 625 sample, a mass loss of 0.04% was observed. The basic wear mechanism of the samples was identified as abrasive wear. The highest friction forces were observed in the 20MnCr5/Cu friction pair (COF = 0.913) and 20MnCr5/EN AW-6061 T0 friction pair (COF = 1.234). The other two samples (Inconel 625, 321 steel) showed a very stable value of the friction force during the roller-block test resulting in a COF between 0.194 and 0.213. Based on the changes in friction force, COFs, and mass changes in friction pair components during wear tests, it can be concluded that potential tools in the form of inserts or working layers manufactured using 3D printing technology, the DMLS method, without additional surface treatment can be successfully used for forming sheets of 321 steel and Inconel 625. Full article

This narrative review explores the role of additive manufacturing (AM) technologies in the production of dental implants, focusing on materials and key AM methods. The study discusses several materials used in implant fabrication, including porous titanium, trabecular tantalum, zirconium dioxide, polymers, and composite materials. These materials are evaluated for their mechanical properties, biocompatibility, and suitability for AM processes. Additionally, the review examines the main AM technologies used in dental implant production, such as selective laser melting (SLM), electron beam melting (EBM), stereolithography (SLA), selective laser sintering (SLS), and direct metal laser sintering (DMLS). These technologies are compared based on their accuracy, material limitations, customization potential, and applicability in dental practice. The final section presents a data source analysis of the Web of Science and Scopus databases, based on keyword searches. The analysis evaluates the research trends using three criteria: publication category, document type, and year of publication. This provides an insight into the evolution and current trends in the field of additive manufacturing for dental implants. The findings highlight the growing importance of AM technologies in producing customized and efficient dental implants. Full article

Laser beam powder bed fusion of metals (PBF-LB/M, or simply L-PBF) has emerged as one of the most competitive additive manufacturing technologies for producing complex metallic components with high precision, design freedom, and minimal material waste. Among the various categories of additive manufacturing processes, L-PBF stands out, paving the way for the execution of part designs with geometries previously considered unfeasible. Despite offering several advantages, parts with overhang features require the use of support structures to provide dimensional stability of the part. Support structures achieve this by resisting residual stresses generated during processing and assisting heat dissipation. Although the scientific community acknowledges the role of support structures in the success of L-PBF manufacturing, they have remained relatively underexplored in the literature. In this context, the present work investigated the impact of laser power and scanning speed on the dimensioning, integrity and tensile strength of single-walled block type support structures manufactured in AISI 316L stainless steel. The method proposed in this work is divided in two stages: processing parameter exploration, and mechanical characterization. The results indicated that support structures become more robust and resistant as laser power increases, and the opposite effect is observed with an increment in scanning speed. In addition, defects were detected at the interfaces between the bulk and support regions, which were crucial for the failure of the tensile test specimens. For a layer thickness corresponding to 0.060 mm, it was verified that the combination of laser power and scanning speed of 150 W and 500 mm/s resulted in the highest tensile resistance while respecting the dimensional deviation requirement. Full article

Additive manufacturing (AM) has emerged as a transformative technology in dentistry, enabling the production of patient-specific dental applications with reduced costs and fabrication times. Despite the growth of applications, a consolidated understanding of current 3D printing technologies, materials, and performance in dental settings remains fragmented. Here, we perform a Systematic Literature Review (SLR) using the PRISMA protocol, retrieving 19 closely related primary studies. The evidence is synthesized across three axes: application domain, AM technology, and critical quality parameters. Dental restorations, prosthetics, crowns, and implants are the most common applications, while fused deposition modeling, stereolithography, digital light processing, selective laser sintering, and laser-directed energy deposition are the most used technologies. AM materials include polymers, metals, and emerging biomaterials. Key quality determinants include dimensional accuracy, wear and corrosion resistance, and photosensitivity. Notably, biocompatibility and cytotoxicity remain underexplored yet critical factors for ensuring long-term clinical safety. The evidence also suggests a lack of in vivo studies, insufficient tribological and microbiological testing, including limited data degradation pathways of AM materials under oral conditions. Understanding that there are disconnects between the realization of the clinical and the economic benefits of 3D printing in dentistry, future research requires standardized testing frameworks and long-term biocompatibility validation. Full article

Background and Objectives: Bone regeneration (BR) is a cornerstone technique in reconstructive dental surgery, traditionally using either barrier membranes, titanium meshes, or perforated non-resorbable membranes to facilitate bone regeneration. Recent advancements in 3D technology, including CAD/CAM and additive manufacturing, have enabled the development of customized scaffolds tailored to patient needs, potentially overcoming the limitations of conventional methods. Materials and Methods: A scoping review was conducted according to the PRISMA guidelines. Electronic searches were performed in MEDLINE (PubMed), the Cochrane Library, Scopus, and Web of Science up to January 2025 to identify studies on digital technologies applied to bone augmentation. Eligible studies encompassed randomized controlled trials, cohort studies, case series, and case reports, all published in English. Data regarding digital workflows, software, materials, printing techniques, and sterilization methods were extracted from 23 studies published between 2015 and 2024. Results: The review highlights a diverse range of digital workflows, beginning with CBCT-based DICOM to STL conversion using software such as Mimics and Btk-3D^®. Customized titanium meshes and other meshes like Poly Ether-Ether Ketone (PEEK) meshes were produced via techniques including direct metal laser sintering (DMLS), selective laser melting (SLM), and five-axis milling. Although titanium remained the predominant material, studies reported variations in mesh design, thickness, and sterilization protocols. The findings underscore that digital customization enhances surgical precision and efficiency in BR, with several studies demonstrating improved bone gain and reduced operative time compared to conventional approaches. Conclusions: This scoping review confirms that 3D techniques represent a promising advancement in BR. Customized digital workflows provide superior accuracy and support for BR procedures, yet variability in protocols and limited high-quality trials underscore the need for further clinical research to standardize techniques and validate long-term outcomes. Full article

The aim of the study was to assess the mechanical and material properties of porous titanium capsules, produced by 3D printing via the DMLS (Direct Metal Laser Sintering) technique based on their potential application as carriers for anticancer drugs. The study used capsules made from the Ti-6Al-4V alloy, and analyzes the impact of geometric parameters, structural features, and printing angles (0°, 45°, and 90°) on their compressive strength. A total of 36 capsules were tested, 18 of type KTD and 18 of type KTM, each in two loading directions. The surface roughness and damage characteristics resulting from mechanical loading have also been evaluated. Statistical analysis of the results was performed using Student’s t-test. The results show that the capsules printed at an angle of 45° are characterized by the highest compressive strength, while their resistance significantly exceeds the values typical of human bone tissue. Additionally, the observed damage does not lead to the formation of sharp edges or loose fragments, which confirms the safety of their use in the body. The high surface roughness promotes tissue integration and limits capsule migration after implantation. The analyses confirm the potential of 3D-printed titanium capsules as effective and safe drug carriers in personalized anticancer therapy. Full article

Ti6Al4V titanium alloy is one of the most studied for its properties after additive manufacturing. Due to its widely use in medical applications, its properties are investigated in various aspects of surface layer property improvement and later compared to conventionally manufactured Ti-6Al-4V. In this study, the corrosion behavior in a 0.9% NaCl solution of shot peened Ti-6Al-4V prepared using direct metal laser sintering (DMLS) was examined using corrosion electrochemical testing and compared with conventionally forged titanium alloy. Shot peening was performed on previously polished samples and subsequently treated with the CrNi steel shots. Two sets of peening pressure were selected: 0.3 and 0.4 MPa. X-ray diffraction analysis (XRD), X-ray micro-computed tomography (Micro-CT), scanning electron microscope (SEM) tests with roughness and hardness measurements were used to characterize the samples. The conventional samples were characterized by an α + β structure, while the additive samples had an α’ + β martensitic structure. The obtained results indicate that the corrosion resistance of the conventionally forged Ti-6Al-4V alloy was higher than DMLSed Ti-6Al-4V alloy. The lowest corrosion rates were noted for untreated surfaces of CM/ref and DMLS/ref samples and reached 0.041 and 0.070 µA/cm², respectively. Moreover, the development of the surface has an influence on corrosion behavior. Therefore, increasing pressure results in inferior corrosion resistance. However, better performance for shot peened samples was reported in the low frequency range. This is due to the refinement of the grain acquired after the peening process. All the results obtained, related to the corrosion behavior, were satisfactory enough that the all samples can be characterized as materials suitable for implant applications. Full article

In this paper, the characterization of the deformation behavior of additively manufactured 3D-printed Ti-6Al-4V alloys during elastic and plastic deformation was carried out on the test samples deformation zone during cold deformation at room temperature. The additive manufacturing process direct metal laser sintering (DMLS) was used to 3D print the Ti-6Al-4V test samples. The temperature, i.e., stress, changes, strain, and strain rate distribution in the deformation zone of the 3D-printed Ti-6Al-4V alloy during elastic and plastic deformation were compared using static tensile tests, thermography, and digital image correlation (DIC) simultaneously. Periodic oscillations of the maximum temperature changes during elastic and plastic deformation were observed in the deformation zone. The thermoelastic effect with the lowest temperature drop between −0.47 °C and −0.54 °C was observed in the deformation zone of the 3D-printed Ti-6Al-4V testing samples during elastic deformation. A significant difference between strain and strain rate localization in the deformation zone was found immediately before fracture of the test sample. Maximum strain amounts in the range of 0.078–0.080 and strain rates of 0.025–0.027 s⁻¹ were determined. Static tensile tests, thermography, and digital image correlation were proved to be valid methods for determining the localization of stress, strain, and strain rate in the deformation zone of 3D-printed Ti-6Al-4V test samples. Full article

Additive manufacturing of metals is limited by a fundamental tradeoff between deposition rates and manufacturability of fine-scale features. To overcome this problem, a laser-ablated bound metal deposition (laBMD) process is demonstrated in which 3D-printed green-state bound metal deposition (BMD) parts are post-processed via laser ablation prior to conventional BMD debinding and sintering. The laBMD process is experimentally characterized via a full-factorial design of experiments to determine the effect of five factors—number of laser passes (one pass, three passes), laser power (25%, 75%), scanning speed (50%, 100%), direction of laser travel (perpendicular, parallel), and laser resolution (600 dpi, 1200 dpi)—on as-sintered ablated depth, surface roughness, width, and angle between ablated and non-ablated regions. The as-sintered ablation depth/pass ranged from 3 to 122 µm/pass, the ablated surface roughness ranged from 3 to 79 µm, the angle between ablated and non-ablated regions ranged from 1° to 68°, and ablated bottom widths ranged from 729 to 1254 µm. This study provides novel insights into as-manufactured ablated geometries and surface finishes produced via laser ablation of polymer–metallic composites. The ability to inexpensively and accurately manufacture fine-scale features with tailorable geometric tolerances and surface finishes is important to a variety of applications, such as manufacturing molds for microfluidic devices. Full article

This article provides a comparative analysis of the dimensional accuracy and post-surface characteristics of gears produced by the 3D printing technique Direct Metal Laser Sintering (DMLS) from 1.2709 steel immediately after printing and after grinding and grinding treatment. The following tests were performed on the fabricated samples: metallography, hardness measurement, self-stress, surface roughness, and the gears’ shape were dimensioned and measured. The results show that post-processing influences the distribution of residual stress and the printed model’s hardness. The results show that heat treatment results in clear directionality marks and micropores, increasing the material’s hardness to 54.3 HRC ± 0.6 HRC, indicating effective strengthening. Grinding significantly improved the holes’ accuracy, changed the compressive intrinsic stresses to a tensile state, and reduced radial runout, improving gear geometries. In addition, it was noted that different results were obtained for roughness parameters depending on the gear tooth tested. Full article

This publication presents the results of research on selected quality features of sample models made using 3D printing technology from the Powder Bed Fusion (PBF) group and a material based on aluminum powder. Two quality areas were analyzed: tensile strength and geometric surface structure. Strength tests of thin-walled models were carried out for samples with four given thicknesses of 1, 1.4, 1.8, and 2 mm and four printing directions, namely, three in the XZ plane and one in the XY plane. The measurement of the geometric structure was carried out using optical measuring devices and by taking into account the assessment of roughness and waviness parameters. Using scanning electron microscopy (SEM), an analysis of the fracture of samples after rupture was carried out and the surface was assessed for technological defects created in the manufacturing process. The test results showed that for thin-walled sample models, there are certain technological limitations regarding the minimum sample thickness in the manufacturing process and that the strength of thin-walled models in relation to “solid” samples depends on both the sample thickness and the printing direction. Roughness parameters that determine functional quality characteristics such as friction and wear were determined and also showed a dependence on the printing direction. Full article

Cemented carbides, renowned for their exceptional strength, hardness, elastic modulus, wear resistance, corrosion resistance, low coefficient of thermal expansion, and chemical stability, have long been indispensable tooling materials in metal cutting, oil drilling, and engineering excavation. The advent of additive manufacturing (AM), commonly known as “3D printing”, has sparked considerable interest in the processing of cemented carbides. Among the various AM techniques, Selective Laser Melting (SLM), Selective Laser Sintering (SLS), Selective Electron Beam Melting (SEBM), and Binder Jetting Additive Manufacturing (BJAM) have garnered frequent attention. Despite the great application potential of AM, no single AM technique has been universally adopted for the large-scale production of cemented carbides yet. The SLM and SEBM processes confront substantial challenges, such as a non-uniform sintering temperature field, which often result in uneven sintering and frequent post-solidification cracking. SLS notably struggles with achieving a high relative density of carbides. While BJAM yields WC-Co samples with a lower incidence of cracking, it is not without flaws, including abnormal WC grain growth, coarse WC clustering, Co-rich pool formation, and porosity. Three-dimensional gel-printing, though possessing certain advantages from its sintering performance, falls short in dimensional and geometric precision control, as well as fabrication efficiency. Cemented carbides produced via AM processes have yet to match the quality of their traditionally prepared counterparts. To date, the specific densification and microstructure evolution mechanisms during the AM process, and their interrelationship with the feedstock carbide material design, printing/sintering process, and resulting mechanical behavior, have not been thoroughly investigated. This gap in our knowledge impedes the rapid advancement of AM for carbide processing. This article offers a succinct overview of additive manufacturing of cemented carbides, complemented by an analysis of the current research landscape. It highlights the benefits and inherent challenges of these techniques, aiming to provide clarity on the present state of the AM processing of cemented carbides and to offer insights into potential future research directions and technological advancements. Full article

In recent years, the application of 3D-printed implant cages or trusses for foot arthrodesis has emerged as a personalized approach to address complex bone defects and deformities. Twenty studies involving different regions of the foot, such as the ankle and subtalar joints, were reviewed to document the 3D-printed custom solutions. The design of these implants is also discussed, including custom titanium trusses and lattice structures, which can promote osseointegration and fit the bone geometries. From a mechanical perspective, these implants proved to be stable and compatible with natural bone, aiming to reduce stress shielding while offering the mechanical strength needed for optimal outcomes. This systematic survey also addresses the additive manufacturing processes involved, namely EBM, SLM, or DMLS. Clinical cases were focused on patients with large bone loss, failed prior fusions, and deformity corrections, with the follow-up results showing high rates of fusion and functional improvement. Of the analyzed studies, three provide level III evidence, while the rest provide level IV or V, consisting of case series or reports. Since 2015, 148 patients have been reported to receive such implants. This review addresses the question, “how effective are 3D-printed titanium cage implants in foot arthrodesis in addressing large bone defects and deformities?” It is the first review to gather data on the use of such customized implants in foot arthrodesis, providing critical insights to enhance their application, including amputation avoidance. This study highlights the advantages of personalized 3D-printed implants in achieving a better anatomical fit, improving clinical outcomes, and ensuring faster recovery times, while also addressing considerations such as the cost and the need for long-term clinical data. Full article

Metal powders for additive manufacturing are expensive, and producing new ones from mined metals has a negative ecological impact. In this work, recycled and reused metal powders from MS1 steel for direct metal laser sintering (DMLS) 3D printing were evaluated in the laboratory. The powders were recycled by melting followed by gas atomizing. Virgin, recycled, and reused metal powders were evaluated using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), metallography analysis, microhardness measurements, particle size distribution (PSD), shape factor by digital image processing (DIP), and flowability testing. The results showed that the particle distribution was modified after recycling. Kurtosis analysis revealed a reduction from −0.64 for virgin powders to −1.29 for recycled powders. The results demonstrated a positive skewness, indicating that the recycled powder contained a greater proportion of smaller particles. The shape factor was also modified and changed from 1.57 for virgin powders to 1.28 for recycled powders. The microstructure also changed, and austenite was found in the recycled powders. The microhardness of recycled powder decreased by 39% compared to the virgin powder. Recycled powders did not flow, using two different funnels to evaluate their flowability. The flowability of used powder was reduced from 4.3 s to 2.9 s. Full article

This narrative review aimed to evaluate the effectiveness of computer-aided design (CAD), computer-aided manufacturing (CAM) milled, and direct metal laser sintering (DMLS) titanium frameworks in hybrid denture prostheses. A structured PICO analysis and a review of ten publications were used to compare titanium frameworks for hybrid dentures made through milling, DMLS, and CAD-CAM milling. Prosthesis success, bone loss, patient satisfaction, framework fit, and biofilm adhesion were among the outcome indicators. The inclusion criteria included comparisons between DMLS and milled titanium frameworks, investigations of hybrid dentures with metal frameworks, and various study designs. The exclusion criteria included reviews, case reports, non-comparative research, and studies unrelated to hybrid dentures. A comprehensive search was performed up to December 2023 across PubMed, PubMed Central, Cochrane Library, Scopus, and Google Scholar, using terms such as CAD-CAM, dental implantation, dental prosthesis, bone loss, damaged maxilla/mandible, implant framework, and bone volume. Ten studies were available for the final analysis. These studies shed light on milled titanium framework’s relative effectiveness and characteristics versus DMLS for implant-supported hybrid dentures. This narrative analysis clarifies the critical roles of the CAD-CAM and DMLS frameworks in implant-supported hybrid dentures. Despite the significant benefits of both of these technologies, it is evident that more investigation is required to identify the optimal framework option for specific clinical scenarios, highlighting the importance of continuing research in this field. Full article