Academic literature on the topic 'DMLS'

In this paper, the nickel-based superalloy SU718 is developed through the Direct Metal Laser Sintering (DMLS), an additive manufacturing process. Further, the material has been focused to study the effect of heat treatment and abrasive particle erosion. Two different heat treatment (HT) cycles are planed with ageing and annealing to enrich the metallurgical quality of the DMLS processed SU718 alloy. The heat treatment is performed with two different combinations of temperatures for annealing/solutionizing followed by ageing to improve the metallurgical properties. The influence of heat treatment on additively manufactured IN718 is imparting variations in the hardness, microstructure, and erosion resistance. Vickers hardness for as built, HT 1, and HT 2 of DMLS alloy is 264.15, 385.55, and 352.43 Hv; which has been increased for 45% for HT 1 and 33% for HT 2 from the as built DMLS alloy. After solutionizing, the grains are refined within the track boundary and the majority of the grains are homogenized. The air jet erosion test arrangement is used to conduct the study at a velocity of 250 m/s and impact angle of 90° at room temperature. The hardness of the treated samples has taken vital role to resist the erosion. The rate of erosion is higher for bare DMLS alloy whereas HT 1 has low erosion rate when compared with HT 2 and bare DMLS alloy. The erosion morphology of the samples was carried out by SEM images, and erosion mechanism is discussed. The ploughing and microcutting were found in all the impact angles, whereas erodent impingement is found in the bare DMLS alloy in additional. The good erosion resistance is observed for HT 1 DMLS alloy in all the impact angles.

Direct Metal Laser Sintering (DMLS) is one of the additive manufacturing technologies involving a metal powder bed and a laser source to obtain components of complex geometry. The fatigue life of an as-built DMLS part is negatively influenced by the rough surface compared to a machined surface. Since most DMLS components are expected to have also stress concentrations, here the combined effect on fatigue of a as-built surface and a geometrical notch in as-built DMLS Ti6Al4V was investigated using a new test methodology. Miniature specimens having three different directions with respect to build direction were fabricated and tested determining the directional fatigue notch sensitivity of as-built DMLS Ti6Al4V Optical inspection of notch surface quality and roughness measurements demonstrated a ranking of the directional notches that inversely correlated to the measured fatigue performance. The link among the curved surface orientation, the peculiar layer-wise additive manufacturing fabrication and the fatigue notch sensitivity is clarified.

Statement of Problem. Direct metal laser sintering (DMLS) is a technology that allows fabrication of complex-shaped objects from powder-based materials, according to a three-dimensional (3D) computer model. With DMLS, it is possible to fabricate titanium dental implants with an inherently porous surface, a key property required of implantation devices.Objective. The aim of this review was to evaluate the evidence for the reliability of DMLS titanium dental implants and their clinical and histologic/histomorphometric outcomes, as well as their mechanical properties.Materials and Methods. Electronic database searches were performed. Inclusion criteria were clinical and radiographic studies, histologic/histomorphometric studies in humans and animals, mechanical evaluations, andin vitrocell culture studies on DMLS titanium implants. Meta-analysis could be performed only for randomized controlled trials (RCTs); to evaluate the methodological quality of observational human studies, the Newcastle-Ottawa scale (NOS) was used.Results. Twenty-seven studies were included in this review. No RCTs were found, and meta-analysis could not be performed. The outcomes of observational human studies were assessed using the NOS: these studies showed medium methodological quality.Conclusions. Several studies have demonstrated the potential for the use of DMLS titanium implants. However, further studies that demonstrate the benefits of DMLS implants over conventional implants are needed.

Background: Direct metal laser Sintering (DMLS) is an additive manufacturing technique that allows fabrication of dental implants and related components with a highly porous surface. To date, no human studies have investigated the soft tissue adhesion and presence of inflammatory infiltrate with porous DMLS healing abutments (HAs), nor have they compared these with the classic machined ones. Purpose: To evaluate the degree of cell adhesion (integrin expression) and the quantity/quality of inflammatory infiltrate, on HAs with different surfaces; full DMLS, full machined, and hybrid (half DMLS and half machined). Methods: Fifty implant patients were randomly assigned to receive one of these different Has: T1, full DMLS (11 subjects); T2, machined in the upper portion and DMLS in the lower one (10 subjects); T3, DMLS in the upper portion and machined in the lower one (19 subjects); T4, full machined (10 patients). Thirty days after placement, circular sections of soft tissues around HAs were retrieved for immunohistochemical evaluation. Results: With regard to the adhesion molecules, the samples showed different intensity of integrin expression, with a statistically significant difference (p < 0.001) between T1 and the other groups. All the samples were positive for the different clusters related to the inflammatory infiltrate (T lymphocytes, CD3; B lymphocytes, CD20; and macrophages, CD68), but a lower infiltrate was found in T1, with statistically significant differences (p < 0.001) among the groups. Conclusions: The HA surface seems to influence the degree of cell adhesion and the inflammatory infiltrate of the surrounding soft tissues.