The material aging in selective laser sintering SLS of polyamide 12 is one challenge, which has to be overcome for implementation this technique serial production. High temperatures and along going processing times lead chemical physical effects the supporting partcake material. Resulting mechanisms are not understood up now. investigations study aims at influence time temperature on molecular changes thermal properties sintering. focus lays global heat exposure bulk und thus changes. Gel...

Selective laser sintering (SLS) of thermoplastic materials is an additive manufacturing process that overcomes the boundary between prototype construction and functional components. This technique also meets requirements traditional established production processes. Crystallization behavior one most critical properties during cooling needs to be fully understood. Due huge influence crystallization on mechanical thermal properties, it important investigate this more closely. A commercial SLS...

A major factor slowing down the establishment of additive manufacturing processes as production is insufficient reproducibility and productivity. Therefore, this work investigates influence ring-shaped beam profiles on process stability productivity in laser-based powder bed fusion AISI 316L. For purpose, weld track geometries single tracks multi-track segments with varying laser power, scan speed, hatch distance, profile (Gaussian three different profiles) are analyzed. To evaluate...

Abstract Next‐generation additive manufacturing processes based on UV‐curing acrylate photopolymers extend the barriers of functional part production by deploying rapid processing speeds, complex geometries with high resolutions, and an extended material spectrum. Many technologies introduce temperature‐dependent curing decomposition behavior acrylates to list process‐related challenges. This investigation targets a comprehensive analysis thermal stability acrylic implementing analyzing...

Achieving precise control in laser-based powder bed fusion of polymers is crucial for ensuring the structural integrity aerospace and automotive components. Closed-loop feedback systems using process monitoring techniques, such as infrared thermography, have potential to provide reliable production by controlling temperature melt. However, challenges arise from complex interactions among variables, part geometry, scan strategy, laser parameters, affecting melted polymer's temperatures...

Additive manufacturing technologies, such as selective laser melting of polymers enable complex parts without tools and forms. Due to high temperature during processing, a degradation the used plastic powder occurs. The unmolded material in building chamber, so-called partcake, can be removed from finished component after reused for another process. To realize reproducible part properties refreshing partcake is necessary. This paper presents results on investigations behavior polyamide 12...

Selective laser sintering (LS) of thermoplastic powders allows for the construction complex parts with higher mechanical properties and durability compared to other additive manufacturing methods. According current model isothermal sintering, semi-crystalline thermoplastics need be processed within a certain temperature range, resulting in simultaneous presence material both molten solid state, which is present during part building. Based on this process model, high cycle times ranging from...

Commercially available materials for selective laser sintering (SLS) include mainly semicrystalline polymers and only a few composites like polyamide 12 filled with glass beads or aluminum. Powder can be used setting tailored properties. Exemplarily, mechanical properties as well thermal electrical conductivity improved. Thermally conductive SLS parts copper particles have not been under investigation before. This study contains the characterization of acting metal filler high conductivity....

In laser-based powder bed fusion of metals (PBF-LB/M), the laser beam shape significantly influences temperature distribution and melt pool dimensions. Recent advances in shaping technology allow for more flexibility changing profile time space. For example, ring-shaped top-hat profiles can improve process efficiency product quality compared to common Gaussian profiles, as they distribute heat input over a larger area. Non-rotationally symmetric shapes are interesting homogeneous fields...

In order to understand the absorption characteristic, a ray trace model is developed by taking into account reflection, and refraction. The paths are resolved on sub-powder grid. For validation, simulation results compared analytic solutions of irradiation laser beam onto plain surface. addition, absorptance, reflectance transmittance PA12 powder layers measured an integration sphere setup with numerical our model. It shown that effective penetration depth can be lower than in bulk material...

Despite the maturity of laser-based powder bed fusion metals (PBF-LB/M), some barriers prevent manufacturing process from fully being established in industry. One drawback is spatter formation, which disadvantageous to PBF-LB/M for three main reasons. First, adhering can initiate coater collision, resulting failure. Second, large may cause lack-of-fusion defects as they require more energy remelt sufficiently compared unprocessed powder. Furthermore, big nonadhering cannot be recycled The...

Multi-material additive manufacturing (AM) pushes the boundaries of modern processing by creating parts with synergetic material-related effects and superior properties. A promising technology is represented so-called fusion jetting (FJ) process which simultaneously combines thermosets thermoplastics into multi-material AM parts. However, bonding behavior between thermoset-reinforced non-reinforced regions proved to be a challenge within FJ investigated in context this study. Based on shear...

By selective laser sintering (SLS), polymer powders are molten layer by to build conventional prototypes or parts in small series with geometrical freedom that cannot be achieved other manufacturing technologies. The SLS process is mainly defined the beam–matter interaction between powder material, radiation and different material characteristics itself. However determination of these problematic because imposes certain requirements sufficiently provided measurement methods. Hence new...

Concerning individualization, the requirements to products have increased. The trend towards individualized serial faces manufacturing techniques with demands of increasing flexibility. Additive generate components directly out a CAD data set while requiring no specific tool or form. Due this additive processes comply, in opposite conventional techniques, these increased on processing technology. With variety available some them high potential series reproducible properties. Selective laser...

Additive manufacturing techniques, such as selective laser melting of plastics, generate components directly from a CAD data set without using specific mold. The range materials commercially available for sintering merely includes some semi crystalline polymers mainly polyamides, which leads to an absence realizable component properties. presented investigations are concerned with the and analysis made filled polymer systems by means sintering. test specimens were generated at varied filler...

In state-of-the-art laser-based powder bed fusion processes, a thin layer of metal is typically melted by means small, Gaussian-shaped laser spot, limiting the stability and productivity process. The application alternative beam shapes current research topic to stabilize, accelerate extend metals, e.g. tailoring microstructure. Static sizes limit theoretically possible process geometry freedom. To overcome those limitations, an approach for flexible highly dynamic shaping presented....

Abstract Several studies demonstrate the potential of pulsed exposure strategies for improving spatial accuracy, surface quality, and manufacturability low-angle overhangs in laser-based powder bed fusion metals. In this paper, those fundamental potentials are transferred to support-free manufacturing heat exchanger structures with partial horizontal made Ti6Al4V. The pulse repetition rates 20 kHz duration 25 µs enabled these complex densities more than 99%. A comparison Archimedean density...

Abstract Next‐generation additive manufacturing (AM) processes such as multiphoton lithography and the fusion jetting (FJ) process demonstrate increasing demands toward temperature stability a thoroughly understood curing behavior of acrylate photopolymers. This investigation targets utilization different kinetic models based on experimentally determined calorimetric results systems. The goal is to determine holistic model that successfully describes simultaneous dependency UV intensity. Two...

Concerning individualization, the requirements to products have increased. Additive manufacturing technologies, such as selective laser melting allow of complex parts without tools and forms. Due this additive processes comply, in opposite conventional techniques, with these increased demands on processing technology. high temperature during processing, a degradation used plastic powder occurs. The non-molten material building chamber, so-called partcake, can be removed after from finished...