Optimization of SLM productivity by aligning 17-4PH material properties on part requirements

2014 ◽  
Vol 20 (6) ◽  
pp. 444-448 ◽  
Author(s):  
A. B. Spierings ◽  
M. Schoepf ◽  
R. Kiesel ◽  
K. Wegener
Keyword(s):  
Mechanical Properties ◽  
Material Properties ◽  
Processing Parameters ◽  
Powder Layer ◽  
Clear Correlation ◽  
Porosity Level ◽  
Content Type ◽  
Wide Range ◽  
Material Porosity ◽  
Process Productivity

Purpose – The purpose of this study is the development of a global SLM-manufacturing optimization strategy taking into account material porosity and SLM process productivity. Selective laser melting (SLM) is a master forming process generating not only a near net shape geometry, but also the material with its properties. Research focuses primarily on optimal processing parameters for maximised material properties. However, the process allows also designing the material structure by internal porosity, affecting global material properties and the process productivity. Design/methodology/approach – The study investigates the influence of the main SLM process parameters on material porosity and consequently on the static mechanical properties of hardened SS17-4PH material. Furthermore, a model for the SLM scanning productivity is developed based on the SLM processing parameters. Findings – The results show a clear correlation between porosity level and mechanical properties. Thereby, the mechanical strength and material modulus can be varied in a wide range. The degree of internal material porosity can be correlated to the energy input defined by a set of SLM processing parameters, such as Laser power, powder layer thickness and scan speed, allowing pre-definition of a specific degree of porosity. Originality/value – Aligning of the SLM processing parameters to the technical material requirements of the parts to be produced, e.g. maximal stresses in service, required E-modulus or lightweight aspects, enlarges the general design space significantly. In combination with the presented model for the scanning productivity, it is further possible to optimize the SLM build rate.

PREDICTION OF PEEK RESIN PROPERTIES FOR PROCESSING MODELING USING MOLECULAR DYNAMICS

2021 ◽  
Author(s):  
KHATEREH KASHMARI ◽  
PRATHAMESH DESHPANDE ◽  
SAGAR PATIL ◽  
SAGAR SHAH ◽  
MARIANNA MAIARU ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Residual Stresses ◽  
Crystallization Kinetics ◽  
Material Properties ◽  
Elevated Temperatures ◽  
Processing Parameters ◽  
Thermomechanical Properties ◽  
Volumetric Shrinkage ◽  
Processing Temperature ◽  
Wide Range

Polymer Matrix Composites (PMCs) have been the subject of many recent studies due to their outstanding characteristics. For the processing of PMCs, a wide range of elevated temperatures is typically applied to the material, leading to the development of internal residual stresses during the final cool-down step. These residual stresses may lead to net shape deformations or internal damage. Also, volumetric shrinkage, and thus additional residual stresses, could be created during crystallization of the semi-crystalline thermoplastic matrix. Furthermore, the thermomechanical properties of semi-crystalline polymers are susceptible to the crystallinity content, which is tightly controlled by the processing parameters (processing temperature, temperature holding time) and material properties (melting and crystallization temperatures). Hence, it is vital to have a precise understanding of crystallization kinetics and its impact on the final component's performance to accurately predict induced residual stresses during the processing of these materials. To enable multi-scale process modeling of thermoplastic composites, molecular-level material properties must be determined for a wide range of crystallinity levels. In this study, the thermomechanical properties and volumetric shrinkage of the thermoplastic Poly Ether Ether Ketone (PEEK) resin are predicted as a function of crystallinity content and temperature using molecular dynamics (MD) modeling. Using crystallization-kinetics models, the thermo-mechanical properties are directly related to processing time and temperature. This research can ultimately predict the residual stress evolution in PEEK composites as a function of processing parameters.

scholarly journals A processing diagram for high-density Ti-6Al-4V by selective laser melting

2018 ◽  
Vol 24 (9) ◽  
pp. 1469-1478 ◽  
Author(s):  
Yinmin (Morris) Wang ◽  
Chandrika Kamath ◽  
Thomas Voisin ◽  
Zan Li
Keyword(s):  
Mechanical Properties ◽  
Energy Density ◽  
Processing Parameters ◽  
High Density ◽  
Low Density ◽  
Laser Powder Bed Fusion ◽  
Content Type ◽  
Powder Bed ◽  
Melt Pool ◽  
Hatch Spacing

Purpose Density optimization is the first critical step in building additively manufactured parts with high-quality and good mechanical properties. The authors developed an approach that combines simulations and experiments to identify processing parameters for high-density Ti-6Al-4V using the laser powder-bed-fusion technique. A processing diagram based on the normalized energy density concept is constructed, illustrating an optimized processing window for high- or low-density samples. Excellent mechanical properties are obtained for Ti-6Al-4V samples built from the optimized window. Design/methodology/approach The authors use simple, but approximate, simulations and selective experiments to design parameters for a limited set of single track experiments. The resulting melt-pool characteristics are then used to identify processing parameters for high-density pillars. A processing diagram is built and excellent mechanical properties are achieved in samples built from this window. Findings The authors find that the laser linear input energy has a much stronger effect on the melt-pool depth than the melt-pool width. A processing diagram based on normalized energy density and normalized hatch spacing was constructed, qualitatively indicating that high-density samples are produced in a region when 1 < E* < 2. The onset of void formation and low-density samples occur as E* moves beyond a value of 2. The as-built SLM Ti-6Al-4V shows excellent mechanical performance. Originality/value A combined approach of computer simulations and selected experiments is applied to optimize the density of Ti-6Al-4V, via laser powder-bed-fusion (L-PBF) technique. A series of high-density samples are achieved. Some special issues are identified for L-PBF processes of Ti-6Al-4V, including the powder particle sticking and part swelling issues. A processing diagram is constructed for Ti-6Al-4V, based on the normalized energy density and normalized hatch spacing concept. The diagram illustrates windows with high- and low-density samples. Good mechanical properties are achieved during tensile tests of near fully dense Ti-6Al-4V samples. These good properties are attributed to the success of density optimization processes.

Effects of Direct Thermal Method Processing Parameters on Mechanical Properties of Semisolid A6061 Feedstock

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
M. F. M. Tajudin ◽  
A. H. Ahmad ◽  
M. M. Rashidi
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Room Temperature ◽  
Processing Parameters ◽  
Holding Time ◽  
Thermal Method ◽  
Pouring Temperature ◽  
Porosity Level ◽  
Experimental Works ◽  
Temperature Water

This paper highlights the effects of pouring temperature and holding time on the mechanical properties of aluminium 6061 semisolid feedstock billets. The semisolid metal feedstock billets were prepared by a direct thermal method (DTM), in which the molten metal was poured into a cylindrical copper mould with a different combination of pouring temperature and holding time before it was solidified in room temperature water. The results show that the sample with pouring temperature slightly above aluminium 6061 liquidus temperature has the lowest porosity, thereby the highest mechanical properties value. The sample with a pouring temperature of 660 °C and holding time of 60 s has the density, tensile strength and hardness properties of 2.701 g/cm3, 146.797 MPa, and 86.5 HV, respectively. Meanwhile, the sample at a pouring temperature of 640 °C and holding time of 20 s has density, tensile strength and hardness properties of 2.527 g/cm3, 65.39 MPa, and 71.79 HV, respectively. The density and fractography tests were conducted to confirm the existence of porosity within the samples. The results from these experimental works suggested that the mechanical properties of DTM semisolid feedstock billet merely depended on processing parameters, which influenced the porosity level within the feedstock billet, thus directly affected their mechanical properties.

Effect of Processing Parameters on Mechanical Properties of Al7175/Boron Carbide (B4C) Composite Fabricated by Powder Metallurgy Techniques

2021 ◽  
Vol 105 ◽  
pp. 8-16
Author(s):  
Guttikonda Manohar ◽  
Krishna Murari Pandey ◽  
Saikat Ranjan Maity
Keyword(s):  
Mechanical Properties ◽  
Composite Material ◽  
Powder Metallurgy ◽  
Sintering Temperature ◽  
Processing Parameters ◽  
Matrix Composites ◽  
Composite Powders ◽  
Porosity Level ◽  
Milling Operations ◽  
Boron Carbide B4c

Metal matrix composites attain a significant position in Industrial, defense, structural and automobile applications. To amplify that strategy there is a need to find out the conditional behavior of the composites and enhancing the properties will be mandatory. The present work mainly investigates on the effect of processing parameters like densification rates, sintering temperature, reinforcement content on the microstructure, mechanical properties of the Al7175/B4C composite material fabricated by mechanical milling and powder metallurgy techniques. Results show there is a grain size reduction and refinement in the composite material through ball milling operations and along with that increasing B4C content in the composite powders make milling conditions very effective. Increasing the sintering temperature results in a consistent grain growth along with that porosity level decreases up to a limit and then attain a steady state, the strength of the composites increases with compaction pressures but reinforcements content effects the strength of the material by losing its ductility making it brittle.

Fuzzy logic approach for investigation of microstructure and mechanical properties of Sn96.5-Ag3.0-Cu0.5 lead free solder alloy

2017 ◽  
Vol 29 (4) ◽  
pp. 191-198 ◽  
Author(s):  
Muhammad Aamir ◽  
Izhar Izhar ◽  
Muhammad Waqas ◽  
Muhammad Iqbal ◽  
Muhammad Imran Hanif ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fuzzy Logic ◽  
Solder Alloy ◽  
Thermal Aging ◽  
Fuzzy Rule ◽  
Rule Base ◽  
Content Type ◽  
Wide Range ◽  
Fuzzy Logic Approach ◽  
Free Solder

Purpose This paper aims to develop a fuzzy logic-based algorithm to predict the intermetallic compound (IMC) size and mechanical properties of soldering material, Sn96.5-Ag3.0-Cu0.5 (SAC305) alloy, at different levels of temperature. The reliability of solder joint in materials selection is critical in terms of temperature, mechanical properties and environmental aspects. Owing to a wide range of soldering materials available, the selection space finds a fuzzy characteristic. Design/methodology/approach The developed algorithm takes thermal aging temperature for SAC305 alloy as input and converts it into fuzzy domain. These fuzzified values are then subjected to a fuzzy rule base, where a set of rules determines the IMC size and mechanical properties, such as yield strength (YS) and ultimate tensile strength (UTS) of SAC305 alloy. The algorithm is successfully simulated for various input thermal aging temperatures. To analyze and validate the developed algorithm, an SAC305 lead (Pb)-free solder alloy is developed and thermally aged at 40, 60 and 100°C temperature. Findings The experimental results indicate an average IMCs size of 5.967 (in Pixels), 19.850 N/mm2 YS and 22.740 N/mm2 UTS for SAC305 alloy when thermally aged at an elevated temperature of 140°C. In comparison, the simulation results predicted 5.895 (in Pixels) average IMCs size, 19.875 N/mm2 YS and 22.480 N/mm2 UTS for SAC305 alloy at 140°C thermally aged temperature. Originality/value From the experimental and simulated results, it is evident that the fuzzy-based developed algorithm can be used effectively to predict the IMCs size and mechanical properties of SAC305 at various aging temperatures, for the first time.

Effect of aluminium content and processing parameters on the microstructure and mechanical properties of laser powder-bed fused magnesium-aluminium (0, 3, 6, 9wt%) powder mixture

2019 ◽  
Vol 25 (4) ◽  
pp. 744-751 ◽  
Author(s):  
Xiaomiao Niu ◽  
Hongyao Shen ◽  
Guanhua Xu ◽  
Linchu Zhang ◽  
Jianzhong Fu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Powder Mixture ◽  
Processing Parameters ◽  
Al Alloy ◽  
Content Type ◽  
Powder Bed ◽  
Al Content ◽  
Microstructure And Mechanical Properties ◽  
Al Powder

Purpose Mg-Al powder mixture was used to manufacture Mg-Al alloy by laser powder bed fusion (LPBF) process. This study aims to investigate the influence of initial Al content and processing parameters on the formability, microstructure and consequent mechanical properties of the laser powder bed fused (LPBFed) component. Design/methodology/approach In this study, Al powder with different weight ratio ranged from 3 to 9 per cent was mixed with pure Mg powder, and the powder mixture was processed using different LPBF parameters. Microstructure and compressive properties of the LPBFed components were examined. Findings It was found that the presence of Al significantly modified the microstructure and improved the mechanical properties of the LPBFed components. Higher volume of ß-Al12Mg17 precipitates was produced at higher initial Al content and higher laser energy density. For this reason, the a-Mg was significantly refined and the compressive strength was improved. The highest yield compressive strength achieved was 279 MPa when using Mg-9 Wt. % Al mixture. Originality/value This work demonstrates that LPBF of Mg-Al powder mixture was a viable way to additively manufacture Mg-Al alloy. Both Al content and processing parameters can be modified to control the microstructure and mechanical properties of the LPBFed components.

Direct polymer additive tooling – effect of additive manufactured polymer tools on part material properties for injection moulding

2019 ◽  
Vol 25 (10) ◽  
pp. 1575-1584 ◽  
Author(s):  
Achim Kampker ◽  
Johannes Triebs ◽  
Sebastian Kawollek ◽  
Peter Ayvaz ◽  
Tom Beyer
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Mechanical Behaviour ◽  
Material Properties ◽  
Tensile Elongation ◽  
Morphological Structure ◽  
Mould Insert ◽  
Content Type ◽  
3D Print ◽  
Standard Specimens

Purpose This study aims to investigate the influence of additive manufactured polymer injection moulds on the mechanical properties of moulded parts. Therefore, polymer moulds are used to inject standard specimens to compare material properties to specimens produced using a conventional aluminium tool. Design/methodology/approach PolyJet technology is used to three-dimensional (3D)-print a mould insert in Digital ABS and selective laser sintering (SLS) technology is used to 3D-print a mould insert in polyamide (PA) 3200 GF. A conventionally aluminium milled tool serves as reference. Standard specimens are produced to compare resulting mechanical properties, shrinkage behaviour and morphology. Findings The determined material characteristics of the manufactured prototypes from the additive manufactured tools show differences in terms of mechanical behaviour to those from the aluminium reference tool. The most significant differences are an up to 25 per cent lower tensile elongation and an up to 63 per cent lower elongation at break resulting in an embrittlement of the specimens produced. These differences seem to be mainly due to the different morphological structure caused by the lower thermal conductivity and greater surface roughness of the polymer tools. Research limitations/implications The determined differences in mechanical behaviour can partly be assigned to differences in surface roughness and morphological structure of the resulting parts. The exact extend of either cause, however, cannot be clearly determined. Originality/value This study provides a comparison between the part material properties from conventionally milled aluminium tools and polymer inserts manufactured via additive tooling.

Effect of processing parameters on forming defects during selective laser melting of AlSi10Mg powder

2020 ◽  
Vol 26 (5) ◽  
pp. 871-879 ◽  
Author(s):  
Haihua Wu ◽  
Junfeng Li ◽  
Zhengying Wei ◽  
Pei Wei
Keyword(s):  
Selective Laser Melting ◽  
Laser Power ◽  
Scanning Speed ◽  
Processing Parameters ◽  
Argon Pressure ◽  
Powder Layer ◽  
Laser Melting ◽  
Content Type ◽  
Scan Speed ◽  
Forming Defects

Purpose To fabricate a selective laser melting (SLM)-processed AlSi10Mg part with almost full density and free of any apparent pores, this study aims to investigate the effect of ambient argon pressure and laser scanning speed on the particles splash during the AlSi10Mg powder bed laser melting. Design/methodology/approach Based on the discrete element method (DEM), a 3D model of random distribution of powder particles was established, and the 3D free surface of SLM forming process was dynamically tracked by the volume of fluid, where a Gaussian laser beam acts as the energy source melting the powder bed. Through the numerical simulation and process experimental research, the effect of the applied laser power and scanning speed on the operating laser melting temperature was studied. Findings The process stability has a fundamental role in the porosity formation, which is process-dependent. The effect of the processing conditions on the process stability and the resultant forming defects were clarified. Research limitations/implications The results shows that the pores were the main defects present in the SLM-processed AlSi10Mg sample, which decreases the densification level of the sample. Practical implications The optimal processing parameters (argon pressure of 1,000 Pa, laser power of 180 W, scan speed of 1,000 mm/s, powder layer thickness of 35 µm and hatch spacing of 50 µm ) applied during laser melting can improve the quality of selective laser melting of AlSi10Mg, Social implications It can provide a technological support for 3D printing. Originality/value Based on the analysis of the pore and balling formation mechanisms, the optimal processing parameters have been obtained, which were argon pressure of 1,000 Pa, laser power of 180 W, scan speed of 1,000 mm/s, powder layer thickness of 35 µm and hatch spacing of 50 µm. Then, a near-fully dense sample free of any apparent pores on the cross-sectional microstructure was produced by SLM, wherein the relative density of the as-built samples is larger than 97.5%.

Effects of Water Exposure on the Mechanical Properties of Early Artists' Acrylic Paints

2004 ◽  
Vol 852 ◽  
Author(s):  
Eric Hagan ◽  
Alison Murray
Keyword(s):  
Mechanical Properties ◽  
Material Properties ◽  
Water Soluble ◽  
Secant Modulus ◽  
Water Exposure ◽  
Wide Range ◽  
Before And After ◽  
Strength And Stiffness ◽  
Paint Films ◽  
Acrylic Paints

ABSTRACTThe mechanical properties of early artist's acrylic paints were investigated under controlled aqueous additive leaching for the purpose of identifying changes caused by cleaning paintings with water. Strength and stiffness values were obtained using a tensiometer to collect stress-strain curves of paint films. The results were compared to those from similar experiments in which paint films were tested under various age, temperature, and relative humidity (RH) values. Strength and stiffness both increased with decreased temperature, decreased RH, increased age, and increased additive removal. The most significant impact on mechanical properties was caused by lowering temperature to the Tg region around 5°C. Dramatic changes in properties were caused by RH fluctuations; however, the magnitudes were negligible in comparison to those induced by low temperature. Removal of water-soluble additives produced a uniform increase in tensile strength and secant modulus at all RH values. The films were equally responsive to fluctuations in RH before and after additive leaching. In comparing the material properties across a wide range of conditions it is evident that the acrylic paints in this study were not significantly altered by the amount of water exposure involved in cleaning paintings.

The Effect of SAS Materials and Modeling in Transferring Impact Loads to the Brain

2010 ◽  
Author(s):  
Parisa Saboori ◽  
Ali Sadegh
Keyword(s):  
Mechanical Properties ◽  
Material Properties ◽  
Brain Injuries ◽  
Impact Load ◽  
Compressive Load ◽  
Impact Loads ◽  
Modeling Methodology ◽  
Wide Range ◽  
The Impact ◽  
The Brain

While subarachnoid space (SAS) trabeculae play an important role in damping and reducing the relative movement of the brain with respect to the skull, thereby reducing traumatic brain injuries, their mechanical properties and modeling are not well established in the literature. A few studies, e.g., Zhang et al. (2002) and Xin Jin et al. (2008) have reported a wide range the elastic modulus of the trabeculae up to three orders of magnitudes. The histology of the trabeculae reveals a collagen based structure. Thus, a few investigators have estimated the mechanical properties of trabeculae based on collagen’s properties. The objective of this study is to determine the stress/strain changes in the brain as a function of the mechanical properties and modeling methodology of the trabeculae, when the loading and the boundary conditions of the model are kept the same. This study was performed through several modeling steps. A wide range of the mechanical properties of the trabeculae was employed and the transductions of blunt impact loads from the skull to the brain were determined. The mechanical properties of the SAS trabeculae were determined based on the validation of the models with experimental results of Sabet et al. (2009). The result indicated that when we use softer material properties for the trabeculae the meningeal layers absorb and damp the impact load. It is also concluded that the material properties of the trabeculae can be simulated by only tension element since the trabeculae buckles with minimal compressive load. Finally, an optimum material property of SAS was proposed.

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