Selective Laser Sintering Process Research Articles

Artificial bone scaffolds of coral imitation prepared by selective laser sintering

Coralline hydroxyapatite (CHA) has been used in clinical for over 20 years. However, coral is an endanger species and has been banned from mining. In addition, coral artificial bone has slow biodegradation of the defects, hindering the growth of new bone. In order to explore the natural coral artificial bone substitute materials, this work proposed using Selective Laser Sintering (SLS) to fabricate natural calcium carbonate/biopolymer composite imitation coral porous structures, and then the surface of the 3D printing product was transformed into a hydroxyapatite thin layer by hydrothermal conversion reaction. The mechanical properties and porosity were optimized by adjusting the SLS processing parameters including laser power, scanning speed and layer thickness. In the composites with the PLLA of 15 wt%, the SLS processing parameters with the laser power of 15 W, laser scanning speed of 1500 mm/s and single layer thickness of 0.08 mm result in the better mechanical properties. After hydrothermal conversion, the products were confirmed to be a mixture of hydroxyapatite (HA) and calcium carbonate by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and energy dispersive X-ray spectroscopy (EDX). The TGA results revealed that increasing the reaction temperature or prolonging the reaction time can increase the degree of hydrothermal reaction and thus promote the transformation of calcium carbonate into hydroxyapatite. The results of cytotoxicity assay and Life/Dead staining showed that the scaffold is not toxic to L929 cells. This work has the materials system innovation and focuses on the study of the effects of the SLS and hydrothermal processes on the mechanical performance and the degree of hydroxylation. Then, the preparation process of imitation coral artificial bone preparation was optimized. it is concluded that the imitation coral artificial bone is a nontoxic biomaterial; however, further study on its osteogenic capacity should be warranted in the future.

An Investigation into Thermal History and Its Correlation with Mechanical Properties of PA12 Parts Produced by Selective Laser Sintering Process

Thermal history is a key factor affecting mechanical properties of polymeric parts made by the selective laser sintering (SLS) process. In this research, the effect of thermal history on the mechanical properties of PA12 parts produced by the SLS process has been investigated. It is hypothesized that different cool-down methods (normal to very slow cooling) and built orientations, resulted from flat and edgewise layouts fabrication, could be influencing factors on the thermal history during the SLS process. The temperature changes at different points inside the powder bed were recorded during the fabrication of specimens. Afterward, the morphology of fabricated samples was examined using scanning electron microscopy. In addition, the degree of crystallinity and melting point of the parts were studied by differential scanning calorimetry analysis. It was found that the built orientation was more effective than the cooling methods on ultimate tensile strength (UTS) and elongation at break (EaB), so that UTS and EaB of the edgewise parts were 10%, 50% greater than the flat parts. On the other hand, the variation of crystallinity with cooling methods has been found to be much less than might be expected from the implemented various fabrication conditions. However, the applied slowest cool-down method slightly increased the edgewise parts crystallinity to 23%, compared to 19.2% for the normal cooled down samples, leading to greater UTS than the normal cooled specimens. The morphology observation of specimens fracture surfaces suggests that better mechanical performance of the edgewise samples is likely connected to fewer defects such as pores and un-melted powder particles remained in their cross sections due to experiencing higher temperature during fabrication. The work is relevant to attempts to build high mechanical performance parts by selective laser sintering.

Mode I and II fracture toughness investigation of Laser-Sintered Polyamide

This paper presents experimental investigations on the geometrical and fracture properties of specimens obtained by Additive Manufacturing technology. The experimental tests were performed on Single Edge Notch Bend (SENB) specimens obtained through the Selective Laser Sintering process, based on the polyamide PA2200 material. The SENB specimens were manufactured using three different process energies-PEs (E1, E2 and E3), respectively three different spatial orientations-SOs (Vertical-V, Horizontal-H and Oblique-O). Symmetric and asymmetric four-point bending tests were used to determine the mode I and II fracture toughness (KIC and KIIC). It was observed that the density (ρ) of the 3D printed specimens is highly dependent on the PE and SO, the highest density values being obtained for the highest PE (E1), respectively for the V-SO. Maximum relative errors of the main geometrical parameters (thickness, length and width) of the SENB specimens were obtained for E3-PE and H-SO. With respect to the fracture toughness, it was observed that, regardless of PE and SO, the KIC values are higher than KIIC ones. The highest KIC value was found for E1 and V-SO, while KIIC highlight the highest value for E1 and H-SO. Finally, analysis of variance (ANOVA) method is used to analyze the influence of various factors on outcome parameters.

Thermal Transport in Nanoparticle Packings Under Laser Irradiation

Abstract Nanoparticle heating due to laser irradiation is of great interest in electronic, aerospace, and biomedical applications. This paper presents a coupled electromagnetic-heat transfer model to predict the temperature distribution of multilayer copper nanoparticle packings on a glass substrate. It is shown that heat transfer within the nanoparticle packing is dominated by the interfacial thermal conductance between particles when the interfacial thermal conductance constant, GIC, is greater than 20 MW/m2K, but that for lower GIC values, thermal conduction through the air around the nanoparticles can also play a role in the overall heat transfer within the nanoparticle system. The coupled model is used to simulate heat transfer in a copper nanoparticle packing used in a typical microscale selective laser sintering (μ-SLS) process with an experimentally measured particle size distribution and layer thickness. The simulations predict that the nanoparticles will reach a temperature of 730 ± 3 K for a laser irradiation of 2.6 kW/cm2 and 1304 ± 23 K for a laser irradiation of 6 kW/cm2. These results are in good agreement with the experimentally observed laser-induced sintering and melting thresholds for copper nanoparticle packing on glass substrates.

Investigation of Mechanical Properties and Binding Mechanism of Metal Based SLS Prototype Coated with Ceramics using High Velocity Oxy Fuel

Abstract In recent times, there has been a growth in use of Rapid Prototyping and Manufacturing (RPM) in various industries globally. Selective Laser Sintering (SLS) used with coated metallic powders has been of special interest as it has widespread application for direct manufacturing especially in the Automotive, Aerospace and Injection Molding industries. This study aims at analyzing the mechanical properties of the fabricated samples at the various stages of a commercial SLS process developed by 3D Systems. Further, a few samples have been coated with a mixture of SiC and Al2O3 using HVOF coating process to improve the mechanical properties and surface properties of the samples. Simultaneously, a study of the surface of the samples was done using SEM analysis. This was aimed to understand the binding mechanism during the various stages of SLS. Finally, we have attempted to establish how the binding mechanism affects the density and the mechanical properties. This will not only establish which industries can directly use the SLS process in its current form with the appropriate coating process, but also lay the groundwork for future research in the variation of machine parameters and powder based raw material for improved mechanical properties

Uncertainties in the attenuation performance of a multi-frequency metastructure from additive manufacturing

Additive manufacturing has been used to propose several designs of phononic crystals and metamaterials due to the low cost to produce complex geometrical features. However, like any other manufacturing process, it can introduce material and geometrical variability in the nominal design and therefore affect the structural dynamic performance. Locally resonant metamaterials are typically designed such that the distributed resonators have the same natural frequency or, in the case of rainbow metastructures, a well-defined spatial profile. In this work, the effects of the break of periodicity caused by additive manufacturing variability on the attenuation performance of a multi-frequency metastructure is investigated. First, an experimental investigation on the manufacturing tolerances of test samples produced from a Selective Laser Sintering process are assessed and variability levels are used to propose a random field model for the metastructure. Subsequently, the stochastic model is used to investigate the vibration suppression performance of broadband multi-frequency metastructures. An analytical model based on a transfer matrix approach is used to calculate transfer receptance due to a point time harmonic force in a finite length metastructure, which is composed of evenly spaced non-symmetric resonators attached to a beam with Π-shaped cross-section. This design creates a multi-frequency metastructure, i.e. band gaps in more than one frequency band. Individual samples of the random fields are used to show that the mistuned resonators can change the vibration attenuation performance of the metastructure and that even small levels of variability, given by less than 1% for the mass and less than 3% for the Young’s modulus can have a significant effect on the overall vibration attenuation performance of the metastructure when considered together. It is also shown that different spatial profiles can have a significant effect on the vibration attenuation performance in both band gaps. Therefore, the modelling of the uncertainty metastructures has to take into account the spatial correlation of the properties of the metastructure resonators. The obtained results are expected to be useful for further robust design in mass produced industrial applications.

Performance analysis of tool electrode prepared through laser sintering process during electrical discharge machining of titanium

Nowadays, additive manufacturing (AM)-based rapid prototyping (RP) is used as a convenient route for making tool electrodes required in electrical discharge machining (EDM). AM enables direct fabrication of complex shaped EDM electrode in comparatively less time in contrast to subtractive machining processes. In this study, an EDM electrode is prepared directly by selective laser sintering (SLS) process using metal matrix composite of aluminium (Al), silicon (Si) and magnesium (Mg). To study the performance of the prepared RP tool electrode in electrical discharge machining, titanium is used as workpiece material and EDM-30 oil as dielectric medium during machining. The performance of the prepared tool electrode is compared with conventional copper and graphite tool electrodes. Experiments have been conducted changing EDM process parameters viz. open circuit voltage (V), peak current (Ip), duty cycle (τ) and pulse duration (Ton) along with three tool electrodes such as RP, graphite and copper tool electrodes. The performance measures considered during the experimental study are material removal rate (MRR), tool wear rate (TWR), average surface roughness (Ra), white layer thickness (WLT), surface crack density (SCD) and micro-hardness (MH) on white layer. SEM and EDX of the machined surface reveal that tool material is generally eroded and deposited on the machined surface with formation of metal carbides. However, tool erosion is more pronounced in case of RP tool electrode. XRD analysis reveals the formation of titanium carbides on the machined surface resulting in increase in the micro-hardness of white layer. Discharge current and tool type are found to be significant parameters influencing the performance measures considered in the study. The surface produced when machined with RP tool electrode exhibits superior surface characteristics while graphite tool electrode produces better MRR and TWR.

A novel microscale selective laser sintering (\u03bc-SLS) process for the fabrication of microelectronic parts

One of the biggest challenges in microscale additive manufacturing is the production of three-dimensional, microscale metal parts with a high enough throughput to be relevant for commercial applications. This paper presents a new microscale additive manufacturing process called microscale selective laser sintering (μ-SLS) that can produce true 3D metal parts with sub-5 μm resolution and a throughput of greater than 60 mm3/hour. In μ-SLS, a layer of metal nanoparticle ink is first coated onto a substrate using a slot die coating system. The ink is then dried to produce a uniform nanoparticle layer. Next, the substrate is precisely positioned under an optical subsystem using a set of coarse and fine nanopositioning stages. In the optical subsystem, laser light that has been patterned using a digital micromirror array is used to heat and sinter the nanoparticles into the desired patterns. This set of steps is then repeated to build up each layer of the 3D part in the μ-SLS system. Overall, this new technology offers the potential to overcome many of the current limitations in microscale additive manufacturing of metals and become an important process in microelectronics packaging applications.

Comparative study of selected indoor concentration from selective laser sintering process using virgin and recycled polyamide nylon (PA12)

Additive manufacturing (AM) stands out as one of the promising technologies that have huge potential towards manufacturing industry. The study on additive manufacturing impact on the environment and occupational exposure are attracting growing attention recently. However, most of the researcher focus on desktop and fused deposition modelling type and less attention given to the industrial type of AM. Usually, during the selective laser sintering process, recycle powder will be used again to reduce cost and waste. This article compares the PM 2.5, carbon dioxide (CO2) and total volatile organic compound (TVOC) concentration between virgin and recycles powder using polyamide-nylon (PA12) towards indoor concentration. Four phases of sampling involve during air sampling accordingly to the Industry Code of Practice on Indoor Air Quality 2010 by DOSH Malaysia. It was found that PM 2.5 and CO2concentration are mainly generated during the pre-printing process. The recycle powder tended to appear higher compared to virgin powder in terms of PM 2.5, and CO2. The peak value of PM 2.5 is 1452 µg/m3 and CO2 is 1218 ppm are obtained during the pre-printing process during 8 hours of sampling. TVOC concentration from recycling powder is slightly higher during the post- printing phase where confirm the influence of the powder cake and PA12 temperature from the printing process. In summary, this work proves that elective laser sintering (SLS) machine operators are exposed to a significant amount of exposure during the SLS printing process. Mitigation strategies and personal protective equipment are suggested to reduce occupational exposure.

The Microstructural Revolution of Ti-6Al-4V Specimens Fabricated by Selective Laser Sintering of Pre-alloyed Powders

Selective laser sintering (SLS) is known as a cutting-edge technique to manufacture complex geometry products. Among various kinds of materials, Ti-6Al-4V is one of the most popular materials for the SLS process. The as-built Ti-6Al-4V products were widely applied in many applications such as aerospace, automobile, and especially in medical and implant parts. The purpose of this research is to investigate the microstructure and other properties of Ti6Al4V pre-alloyed powders produced by selective laser sintering technique. Through this research, the direct fabrication of Ti6Al4V metal object by SLS machine has been carried out using MetalSys250 machine. Different parameters of the SLS process were used to produce 1cm x1cmx1cm cubic samples and then microstructure, as well as mechanical properties of the as-built samples were investigated. Powder particles are fully dense, possess a spherical shape and are composed of acicular α phase. The as-build sample shows the oriented acicular martensitic phase with the defined columnar grain structures.

PREPARATION OF Cu-SiO2/PA12 COMPOSITE POWDERS BY ELECTROLESS PLATING FOR USE IN SLS PROCESSING

In this work, SiO2-encapsulated copper particles/PA12 (Cu-SiO2/PA12) composite powders were prepared by electroless composite plating, and the laser sintering behavior was investigated. Results showed that Cu, Cu2O, CuO, and SiO2 (Cu-SiO2) composite particles were plated on the surface of KH550-modified PA12 powders. The Cu-SiO2 particles existed independently on PA12 surface, and the size was around 200 nm. The melting temperature and crystallization temperature of Cu-SiO2/PA12 composite powders were 183∘C and 150∘C. The results indicate that the selective laser sintering (SLS) process involved the contact of Cu-SiO2/PA12 powders, the formation of sintering neck, the growth of sintering neck, and the formation of fused solid. The Cu-SiO2 composite particles uniformly dispersed in the part due to surface tension, and the contact interface was good due to their similar polarity. The Cu-SiO2/PA12 SLS parts had excellent dimensional precision. The tensile strength of the 15[Formula: see text]W-sintered Cu-SiO2/PA12 specimen was 48[Formula: see text]MPa.

Surface Characteristics of EDMed Titanium Alloy and AISI 1040 Steel Workpieces Using Rapid Tool Electrode

Recently, additive manufacturing-based rapid tools are conveniently used in electrical discharge machining (EDM) process because complex-shaped tools can be produced in less time as compared to various conventional and nonconventional tool-making processes. However, sustainability of a rapid tool in terms of electrical and mechanical environment experienced in EDM process needs to be evaluated before recommending for real application. To address this issue, performance of AlSi10Mg tool manufactured by selective laser sintering process, a rapid prototype (RP) process, is compared with conventional copper and brass tools while machining titanium alloy and AISI 1040 steel in EDM process using EDM-30 oil as dielectric medium. Specifically, influence of EDM variables such as pulse-on-time (Ton) and discharge current (Ip) on performance measures like average surface roughness of machined surface (Ra), surface crack density, white layer thickness and micro-hardness of white layer has been studied. The study indicates that tool type is the most influential parameter followed by discharge current and pulse-on-time for both the workpiece materials. Superior surface characteristics can be obtained using AlSi10Mg RP tool at low level of parametric setting of discharge current and pulse-on-time. The machined surface by different tools is examined by scanning electron microscope to observe surface cracks. Energy-dispersive X-ray spectroscopy analysis reveals transfer of tool materials into the machined surface resulting in increase in percentage of carbon and oxygen on the machined surfaces. Finally, Grey-TOPSIS method has been adopted to obtain optimal parametric setting that simultaneously optimizes all the performance measures.

ПОЛУЧЕНИЕ ВЫЖИГАЕМЫХ МОДЕЛЕЙ МЕТОДОМ 3D-ПРИНТИНГА ДЛЯ ОТЛИВОК ГАЗОТУРБИННЫХ ДВИГАТЕЛЕЙ

A study of the fuse deposited pattern and castings of gas turbine hot section, which was obtained with additive manufacturing, has been carried out in the present article. A pattern of the castings had been produced by selective laser sintering (SLS) process from the polystyrene powders according to developed in special program complex 3D-model. With involving of the obtained FDM-pattern via burned pattern casting process have been produced a parts of gas turbine hot section from nickel-base superalloy VKh4L-VI. The castings were investigated as in the as-cast state, thus and after inherent superalloy VKh4L-VI heat treatment with prior hot isostatic pressing (HIP). An analysis of the obtained FDM-pattern for the presence of surface defects and geometry compliance are provided, together with the macro- and microstructure study of obtained castings and evaluation of mechanical properties and stress rupture strength results. It was established that investigated patterns as precisely as possible reproduce dimensions accuracy of the parts, and castings had satisfactory surface cleanliness, roughness, dense and middle crystalline macrostructure. Micro-structure of castings material is typical for nickel-base superalloy VKh4L-VI in the as-cast state with carbides, carbonitrides and eutectic phase’s presence.HIP with subsequent heat treatment provides almost full micro porosity releases in the inner volumes of the metal and getting more uniform solid-state, almost full eutectic dissolving, and carbides dispersivity. Mechanical properties and stress rupture strength (rupture life) of the specimens produced by considered production processes meet the specification requirements. Application of HIP with subsequent heat treatment (homogenization and ageing) for specimen’s production provides slightly bigger indexes of mechanical properties at room temperature.Selective laser sintering application for FDM-patterns production made it possible to obtain qualitative castings with satisfactory microstructure, the acceptable level of the properties and realize traditional advantages inherent for both considered processes.

Fabrication of Al2O3‐SiO2 ceramics through combined selective laser sintering and SiO2‐sol infiltration

AbstractIn this study, different posttreatment methods, including silica‐sol infiltration (SI), vacuum silica‐sol infiltration (vSI), debinding (DB), and pressure‐less sintering (PS), were combined with selective laser sintering (SLS) to fabricate Al2O3‐SiO2 ceramics. The macro‐morphology and microstructure of sample fabricated under different laser processing parameters and posttreatment process were investigated. Results show that the geometric dimension accuracy and surface quality of the final samples can be effectively improved with appropriate SLS parameters and posttreatment. The optimal SLS processing parameters are determined to be 0.15 mm, 10 W, 0.1 mm, and 1500 mm/s for the hatch spacing, laser power, layer thickness, and scanning speed, respectively. The SLS/DB/vIN/FS samples have the smallest linear shrinkage ratio (<1%), the least warpage degree (<3%), and the best surface quality (surface altitude difference <170 μm). Mullite, quartz, corundum, and cristobalite composed the phases of the sample, of which cristobalite came largely from the infiltrated silica‐sol. Since a higher amount of silica‐sol infiltrated into the sample under SLS/DB/vIN/FS process, more cristobalite phase formed in the pore of the sample during sintering, which avoided excessive microstructure shrinkage during sintering and ensured the high geometric accuracy and surface quality of the final sample.

Indoor Air Concentration from Selective Laser Sintering 3D Printer using Virgin Polyamide Nylon (PA12) Powder: A Pilot Study

Environmental emission from additive manufacturing (AM) have attracted much attention recently. The capability in fabricating complex part make AM famous in developing prototype and product in various industries especially in aerospace, medical, automotive, and manufacturing industries. However, the study on emission and exposure mainly focusses on the desktop type such as fused deposition modelling. This study investigates the emission and indoor concentration from powder bed fusion of selective laser sintering (SLS) technologies. Prior to the investigation, virgin PA12 undergone characterization in terms of morphology, size and thermal analysis. Calibration block using virgin polyamide nylon (PA12) are selected to be printed in this study. Parameters such particulate matter size 2.5 µm (PM 2.5), total volatile organic compound (TVOC), carbon dioxide (CO2), formaldehyde, temperature and relative humidity (RH) are set to be monitored through real time sampling of 8 hours based on Industry Code of Practice on Indoor Air Quality 2010 by Department Occupational Safety and Health (DOSH) Malaysia. Four phases of printing process involve are background data, preprinting, during printing and post printing. Based on the study it was found that PM 2.5 and CO2 exceed the acceptable limit recommended by DOSH Malaysia during preparation of powder (preprinting) at 1218 ppm and 1070 µg/m3 respectively. Meanwhile TVOC concentration was influence by the sintered powder temperature and recorded at 0.5 ppm. Temperature, relative humidity and formaldehyde were maintained throughout the SLS process. Mitigation strategies using mechanical ventilation and personal protective equipment (PPE) are recommended to be used to reduce potential of occupational hazard to the operators.

Obtainment of the alumina polyamide-coated spherical particles

The indirect selective laser sintering (SLS) process consists of a powder-based additive manufacturing (AM) technique. Recently, an attempt was carried out using the indirect-SLS method on ceramics to obtain complex geometric parts without the need to fabricate tools or molds. In this context, the ceramic particles employed in indirect-SLS must be coated with a polymer layer and retain spherical format. Currently, several processes of encapsulation and balling up of ceramic particles are available, among which thermally induced phase separation (TIPS) is noteworthy. The present study describes the synthesis, via TIPS, of spherical micrometric alumina particles coated with polyamide 12 to be employed in indirect-SLS. Dimethyl sulfoxide (DMSO) was used as a solvent to obtain these particles. After encapsulation, the agglomerates were characterized according to granulometry, microstructure, thermal behavior, and flowability. The obtained results delineated the ideal conditions to synthesize agglomerates with adequate flowability, particle size profile, and similar thermal behavior to that verified for PA-12, a currently used material in SLS printing. Based on the results of the present study, it is possible to confirm the effectiveness of the TIPS technique in obtaining ceramic polymer-coated spherical particles that are suitable for use in AM processes via indirect-SLS.

Comparison of the Microstructure of Machined and Laser Sintered Shaped Charge Liner in the Hydrodynamic Regime

To gain further insight into the mechanisms underlying jet formation and elongation of laser sintered shaped charge liners under high strain rate deformation, Cu–Cr–Zr alloy liners fabricated by selective laser sintering process were deformed by explosive detonation. Their as-manufactured (liner) and resultant (slug) microstructure have been investigated in comparison with those of traditional machined liners employing both optical and scanning electron microscopy. The resultant slug microstructure of both machined and laser sintered liners revealed a smaller refined equiaxed grain size consistent with traditionally fabricated liners, characteristic of dynamic recrystallization. The disappearance of the (originally present) pores in the post-shot/recovered material microstructure was observed for laser-sintered liners. Comparison of the forward and rear region of the slug revealed variations in liner deformation, a result attributed to temperature variation across the slug. In contrast with the machined liner, a unique feature of precipitation, observed in the ending (slug) microstructure of the laser sintered liner is indicative of the associated extreme high strain and strain rate liner deformation which occurred during slug formation. The precipitates are likely compounds of Chromium and Zirconium which are constituents of the laser sintered copper alloy—the first time this observation is reported. This study provides a link between post charge evolution microstructure and liner manufacturing processes, potentially providing a new route to help optimise jet formation and effectiveness.

Fabrication of Porous Hydrogenation Catalysts by a Selective Laser Sintering 3D Printing Technique.

Three-dimensional selective laser sintering printing was utilized to produce porous, solid objects, in which the catalytically active component, Pd/SiO2, is attached to an easily printable supporting polypropylene framework. Physical properties of the printed objects, such as porosity, were controlled by varying the printing parameters. Structural characterization of the objects was performed by helium ion microscopy, scanning electron microscopy, and X-ray tomography, and the catalytic performance of the objects was tested in the hydrogenation of styrene, cyclohexene, and phenylacetylene. The results show that the selective laser sintering process provides an alternative and effective way to produce highly active and easily reusable heterogeneous catalysts without significantly reducing the catalytic efficiency of the active Pd/SiO2 component. The ability to control the size, porosity, mechanical properties, flow properties, physical properties, and chemical properties of the catalyst objects opens up possibilities to optimize devices for different reaction environments including batch reactions and continuous flow systems.

Improvement on Selective Laser Sintering and Post-Processing of Polystyrene.

Amorphous polymers are heavily utilized materials in selective laser sintering (SLS) due to their good dimensional accuracy. However, sintered parts of amorphous polymers cannot be used as functional parts owing to their poor forming performance, including their low relative densities and tensile strength. Therefore, post-processing methods are employed to enhance the mechanical properties of amorphous polymers SLS parts without damaging their relatively high dimensional accuracy. In this study, the forming process of selective laser sintering (SLS) and post-processing on polystyrene (PS) was investigated. The orthogonal experiment was designed to obtain the optimal combination of process parameters. The effect of a single process parameter and the laser volumetric energy density (LVED) on dimension accuracy and warpage of the sintered parts were also discussed. In addition, a three-dimensional (3D) thermal model was developed to analyze the temperature fields of single-layer SLS parts and PS powder sintering mechanism. Then, infiltrating with epoxy resin was employed to enhance the mechanical properties of the PS parts. Good resin-infiltrated formulation was obtained based on the mechanical property tests and fractured surface analysis. This research provides guidance for SLS process and post-processing technology in polymers.

Validation of an Experimental Procedure to Quantify the Effects of Powder Spreadability on Selective Laser Sintering Process

Glass beads powders of different particle size were spread with a procedure similar to the one adopted for Selective laser sintering in order to verify the effect of the powder compression produced with a roller spreading tool. The effect is verified in terms of indentation strength and of mechanical strength of the sintered specimens. Results indicate a significant effect of powder compression on the SLS process with fine powders.