scholarly journals PP in 3D Printing - Technical and Economic Aspects

2019 ◽  
Vol 56 (4) ◽  
pp. 931-936
Author(s):  
Ionel Danut Savu ◽  
Sorin Vasile Savu ◽  
Dalia Simion ◽  
NicuȘor-Alin Sirbu ◽  
Mirela Ciornei ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
3D Printing ◽  
Entire Range ◽  
Microscopic Analysis ◽  
Heating Cycle ◽  
Economic Aspects ◽  
Dynamic Shear ◽  
Elongation Viscosity ◽  
Lower Viscosity ◽  
Storage Energy

FDM is 3D printing technology using mainly PLA and ABS as filament materials. PP has close characteristics to PLA and, due to that, is a potential material for for deposition. Paper aims to analyse the behaviour of PP during heating cycle specific to 3D printing process. Macroscopic and microscopic analysis of the deposited strings have been performed. They revealed less stiffness of the PP deposition comparing to PLA, which is due to the lower viscosity of PP. DSC Thermal analysis has been done at it revealed a 30% higher heat flux in PP comparing to PLA and that increases its fluidity. It was recorded a difference between the elongation viscosity of the PP filament and the PP deposited by FDM process. After 5s the deposited PP proves higher values for the elongation viscosity. Dynamic shear rheology measurements the was applied on samples deformed under 210 kN at 190oC. It has been found that the PP requires lower storage energy and that means that it has a lower viscosity for the entire range of applied frequencies. In the same time, the complex viscosities prove different behavior. To improve the control of the deposition shape, it is necessary to reduce the extrusion temperature with 4-5%. That leads to economy in power consumption.

scholarly journals Laser Marking of PLA FDM Printed Products

2019 ◽  
Vol 57 (2) ◽  
pp. 228-238
Author(s):  
Ionel Danut Savu ◽  
Sorin Vasile Savu ◽  
Nicusor-Alin Sirbu ◽  
Mirela Ciornei ◽  
Robert Cristian Marin ◽  
...  
Keyword(s):  
3D Printing ◽  
Storage Modulus ◽  
Laser Heating ◽  
Loss Modulus ◽  
Elastic Response ◽  
Heating Cycle ◽  
Laser Marking ◽  
Printing Process ◽  
Elongation Viscosity ◽  
High Elasticity

The paper aimed to reveal, qualitatively and quantitatively, the modifications suffered by the PLA during the complex heating cycle specific to the 3D printing followed by laser marking. The obtained results showed that the melting point of the PLA decreases from 162.2oC (which is specific to PLA filament) to 153.1oC after the 3D printing process and to 149.7oC after the laser heating. The glass transition suffered the same lowering after the printing process but an important increasing after the laser heating. The elastic modulus evolution proved a decreasing of the plasticity and that is hapenning when the material suffers an increasing of its rigidity. The elongation viscosity was analyzed and its values were decreasing with the increasing of the temperature that happened on the material. The decreasing was produced by the reduction of the elasticity, when the chain branches are decreasing their length. The decreasing is more pronounced with the increasing of the temperature. The ratio between the loss modulus to the storage modulus and quantifies the way in which the PLA absorbs and disperses energy moves its peak from 65oC (curve specific to the PLA filament) to 45oC (curve specific to the last layer deposited by 3D printing process and re-heated by laser beam for marking). The peak means the lowest storage modulus, which is a measure of elastic response of a material, so the transition from glass to high elasticity moves to the lower temperatures.

Experimental and numerical thermal analysis of open-cell metal foams developed through a topological optimization and 3D printing process

2018 ◽  
Vol 83 (1) ◽  
pp. 10904 ◽  
Author(s):  
Abdelatif Merabtine ◽  
Nicolas Gardan ◽  
Julien Gardan ◽  
Houssem Badreddine ◽  
Chuan Zhang ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
3D Printing ◽  
Numerical Simulations ◽  
Lattice Model ◽  
Metal Foam ◽  
Complex Geometry ◽  
Metal Foams ◽  
Topological Optimization ◽  
Plaster Mold ◽  
Open Cell

This study focuses on the thermal analysis and comparing a lattice model and an optimized model of open-cell metal foams manufactured thanks to a metal casting process. The topological optimization defines the complex geometry through thermal criteria and a plaster mold reproduces it in 3D printing to be used in casting. The study of the thermal behavior conducted on the two open foam metal structures is performed based on several measurements, as well as numerical simulations. It is observed that the optimized metal foam presented less and non-homogenous local temperature than the lattice model with the gap of about 10 °C between both models. The pore size and porosity significantly affect the heat transfer through the metal foam. The comparison between numerical simulations and experimental results regarding the temperature fields shows a good agreement allowing the validation of the developed three-dimensional model based on the finite element method.

Thermal-Mechanical Study of 3D Printing Technology for Rail Repair

2018 ◽  
Author(s):  
Ershad Mortazavian ◽  
Zhiyong Wang ◽  
Hualiang Teng
Keyword(s):  
Thermal Analysis ◽  
Thermal Expansion ◽  
3D Printing ◽  
Stress Distribution ◽  
Temperature Gradient ◽  
Initial Temperature ◽  
Mechanical Analysis ◽  
Von Mises Stress ◽  
Additive Materials ◽  
Von Mises

The complicated steel wheel and rail interaction on curve causes side wear on rail head. Thus, the cost of maintenance for the track on curve is significantly higher than that for track on a tangent. The objective of this research is to develop 3D printing technology for repairing the side wear. In this paper, the study examines induced residual thermal stresses on a rail during the cooling down process after 3D printing procedure using the coupled finite volume and finite element method for thermal and mechanical analysis respectively. The interface of the railhead and additive materials should conserve high stresses to prevent any crack initiation. Otherwise, the additive layer would likely shear off the rail due to crack propagation at the rail/additive interface. In the numerical analysis, a cut of 75-lb ASCE (American Society of Civil Engineers) worn rail is used as a specimen, for which a three-dimensional model is developed. The applied residual stresses, as a result of temperature gradient and thermal expansion coefficient mismatch between additive and rail materials, are investigated. At the beginning, the worn rail is at room temperature while the additive part is at a high initial temperature. Then, additive materials start to flow thermal energy into the worn rail and the ambient. The thermal distribution results from thermal analysis are then employed as thermal loads in the mechanical analysis to determine the von-Mises stress distribution as the decisive component. Then, the effect of preheating on residual stress distribution is studied. In this way, the thermo-mechanical analysis is repeated with an increase in railhead’s initial temperature. In thermal analysis, the temperature contours at different time steps for both the non-preheated and preheated cases indicate that preheating presents remarkably lower temperature gradient between rail and additive part and also represents a more gradual cooling down process to allow enough time for thermal expansion mismatch alignment. In mechanical analysis, the transversal von-Mises stress distribution at rail/additive interface is developed for all cases for comparison purposes. It is shown that preheating is a key factor to significantly reduce residual stresses by about 40% at all points along transversal direction of interface.

On the Development of a 3D Printer for Combinatorial Structural Composite Research

2015 ◽  
Author(s):  
Seyed Allameh
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
Partial Slip ◽  
Shear Stresses ◽  
3D Printer ◽  
Dynamic Shear ◽  
Structural Composites ◽  
Structural Composite ◽  
The Right ◽  
Selection Of

Bioinspired materials have enabled the fabrication of tough lightweight structures for load- and impact-bearing applications of which an example is fiber-reinforced plastics use in aerospace. If applied to the field of construction, biomimicked composites can save lives, otherwise lost to earthquakes and other disasters that cause collapse of buildings. The main culprit is the low resistance of structures exposed to dynamic shear stresses, typical of earthquakes. Recent work on the application of biomimicry to structural composites has clearly shown the advantage of these materials in resisting dynamic shear. Adding natural or synthetic reinforcement fibers may alleviate the need for conventional steel rebars and make it possible to print buildings by conventional 3D printing technology. The main hurdles are to find the right type of composite that is compatible with 3D printing and the right process for deposition of such material. In the past, combination of carbon fiber, glue and concrete has been demonstrated to enhance the toughness of resulting structural composites. Inspired by the microstructure of oyster and mother of pearl, layering of these materials mitigates the localization of deformation by distributing the imposed displacement over a large area. The intricate structure of these layers, and the minute details of the interfaces are important for affecting good dynamic shear resistance. In nacre, a partial slip of sandwiched layers occurs before it stops and deformation is transferred to the adjacent area. This energy-absorption capability underlies the high-toughness behavior of nacre and similar structures. By mimicking nacre, bone and tooth, it is possible to benefit from their good properties, however, it is important to determine the type of material, layering scheme, geometry, and other factors that affect mechanical properties. A recently-developed medium-sized 3D printer was developed to deposit structural materials. These include cement, plaster, polymer and clay. Combinatorial structural composite research (CSCR) comprising the simultaneous fabrication and characterization of multiple specimens with different microstructures allows fair comparison of mechanical properties of various structural composites. Novel application of deposition techniques to the extrusion of plaster, cement and clay paves the way to layer these materials along with glue and fibers in desired schemes. Use of ANOVA tables in the selection of various types of ceramics, polymers and reinforcement materials for the fabrication of different composites will be discussed. In addition to selection of the type of the materials, deposition schemes such as those of solid and hollow structures, different layer thickness applications, and the effect of timing will be elucidated. Microscopy conducted on the fractured surfaces enables the investigation of the mechanisms of fracture and failure for these CSCR composites. The details of experiments conducted, microscopy performed and the results of mechanical tests will be presented.

scholarly journals The Impact of the Preparation Method on the Properties of Orodispersible Films with Aripiprazole: Electrospinning vs. Casting and 3D Printing Methods

Pharmaceutics ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1122
Author(s):  
Ewelina Łyszczarz ◽  
Witold Brniak ◽  
Joanna Szafraniec-Szczęsny ◽  
Tomasz Mariusz Majka ◽  
Dorota Majda ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
Microscopic Analysis ◽  
Storage Condition ◽  
Stability Studies ◽  
Disintegration Time ◽  
Manufacturing Method ◽  
Orodispersible Films ◽  
Swallowing Problems ◽  
The Impact

Orodispersible films (ODFs) address the needs of pediatric and geriatric patients and people with swallowing difficulties due to fast disintegration in the mouth. Typically, they are obtained using the solvent casting method, but other techniques such as 3D printing and electrospinning have already been investigated. The decision on the manufacturing method is of crucial importance because it affects film properties. This study aimed to compare electrospun ODFs containing aripiprazole and polyvinyl alcohol with films prepared using casting and 3D printing methods. Characterization of films included DSC and XRD analysis, microscopic analysis, the assessment of mechanical parameters, disintegration, and dissolution tests. Simplified stability studies were performed after one month of storage. All prepared films met acceptance criteria for mechanical properties. Electrospun ODFs disintegrated in 1.0 s, which was much less than in the case of other films. Stability studies have shown the sensitivity of electrospun films to the storage condition resulting in partial recrystallization of ARP. These changes negatively affected the dissolution rate, but mechanical properties and disintegration time remained at a desirable level. The results demonstrated that electrospun fibers are promising solutions that can be used in the future for the treatment of patients with swallowing problems.

scholarly journals Fabrication of Conductive Filaments for 3D-printing: Polymer Nanocomposites

2020 ◽  
Vol 10 (6) ◽  
pp. 6577-6586 ◽  
Keyword(s):  
3D Printing ◽  
Carbon Nanostructures ◽  
Stress Test ◽  
Microscopic Analysis ◽  
Processing Temperature ◽  
Electrical Measurements ◽  
Electrically Conductive ◽  
3 Dimensional ◽  
Dimensional Printing ◽  
Mixture Homogeneity

With the promise of producing electrically conductive circuits, 3-dimensional-printing (3DP) filaments infused with carbon nanostructures are now commercially available; however, it is still difficult to control the mixture homogeneity between the polymer and conductive charge thereby increasing its conductive mobility. Herein, we describe the fabrication, characterization and application of conductive polymernanocomposites processed into filament form intended for 3DP of electronic circuits. For this, graphene, carbon nanotubes and carbon black fillers were loaded into several resin matrixes including ABS, PLA, HDPE, LLDPE, PETG, and PP. Electrical measurements, thermal, crystallographic and morphological profiles are here described. Filaments obtained present values of resistivity and conductivity ranging from 0.2 to 1.4 S/cm and 0.71 to 5.0 S/cm respectively. Thermal analysis showed that the processing temperature of materials studied is inside the standard range for extrusion and 3D-printing. Microscopic analysis revealed a heterogeneous mix between resins and fillers. The electrical and thermal stress test showed increases in resistivity and decreases in conductivity of prepared filaments since these quantities are inversely proportional.

Physical-Chemical Studies and Evaluation of the Suitability of Chernoyarskoe Deposit’s Diatomite for the Synthesis of Foam Glass

2020 ◽  
Vol 299 ◽  
pp. 188-193
Author(s):  
Elena A. Yatsenko ◽  
V.A. Smoliy ◽  
A.A. Chumakov
Keyword(s):  
Thermal Analysis ◽  
Foam Glass ◽  
Microscopic Analysis ◽  
Mineralogical Composition ◽  
Raw Material ◽  
Polymorphic Transformations ◽  
Chemical Methods ◽  
Physical Chemical ◽  
Chemical Studies ◽  
Complex Thermal Analysis

The macro- and microstructure is investigated by microscopic analysis methods. The elemental, granulo-metric and mineralogical composition of diatomite of the Chernoyarskoe deposit is determined. As a result of complex thermal analysis, using a differential scanning calorimeter, intervals of continuous dehydration of diatomite were studied, as well as polymorphic transformations of quartz and other minerals. Physical-chemical methods of research have discovered that diatomite of the Chernoyarskoe deposit contains amorphous silica, quartzite, clay impurities, opal and minor amounts of calcite, mica, zeolite, and so this diatomite is a promising raw material for the synthesis of foam glass.

scholarly journals Economical and technical aspects of using air heat pumps for hot water

2018 ◽  
Vol 46 ◽  
pp. 00014 ◽  
Author(s):  
Mariusz Szreder
Keyword(s):  
Heat Pump ◽  
Storage Tank ◽  
Heat Pumps ◽  
Hot Water ◽  
Heating Cycle ◽  
Economic Aspects ◽  
Technical Aspects ◽  
Domestic Hot Water ◽  
Heating Water ◽  
Higher Temperature

The paper presents selected technical and economic aspects related to the use of air heat pumps for the preparation of domestic hot water DHW. The research shows that heating the water in the 130 dm3 storage tank with the A21/W30-50 profile lasted an average of 130 minutes, and the heat pump consumed about 2.2 kWh of energy per one heating cycle. Heating water in a 130 dm3 storage tank from 25°C to 40°C lasted an average of 60 minutes, while heating water for another 5°C took 30 minutes. The operation of the heat pump in the higher temperature of the water in the storage tank is less effective, making the heating of water in the tank above 50°C is ineffective.

Characterization of Materials by Thermoanalytical Techniques

MRS Bulletin ◽  
1988 ◽  
Vol 13 (7) ◽  
pp. 23-27 ◽  
Author(s):  
P.K. Gallagher
Keyword(s):  
Thermal Analysis ◽  
Entire Range ◽  
Physical Property ◽  
Chemical Concentration ◽  
Thermal Methods ◽  
Thermoanalytical Techniques ◽  
The Subject ◽  
Characterization Of Materials ◽  
Standard Techniques

The generally accepted definition for thermal analysis is that it covers “a group of techniques in which a physical property for a substance and/or its reaction product(s) is measured as a function of temperature while the substance is subjected to a controlled temperature program.” From this broad scope, it is evident that at some point in their careers nearly all experimental materials scientists have been practicing thermal analysts. It is also obvious that the techniques of thermal analysis are applicable to the entire range of materials. Consequently, it is difficult, it not impossible, to properly review such a topic in several pages, but I hope that a carefully selected handful of examples will acquaint the readers with the standard techniques and the enormous versatility inherent in thermal methods. One aspect which simplifies the review is that the methods are conceptionally very simple and do not require extensive descriptions.Table I describes some of the more common techniques for which examples will be presented. Obviously, many more properties have been studied; however, those listed will suffice as an introduction to the subject.Because all information derived from thermal methods frequently has only an indirect correlation with the chemical concentration or process of interest, it is important to use more than one technique where possible.

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