Resistive-IR Hybrid Heating in FDM Printing

2021 ◽  
Vol 890 ◽  
pp. 157-164
Author(s):  
Mirela Ciornei ◽  
Ionel Dănuț Savu ◽  
Nicușor Alin Sîrbu ◽  
Sorin Vasile Savu ◽  
Bebe Adrian Olei
Keyword(s):  
Heat Source ◽  
Deposition Process ◽  
Tensile Tests ◽  
Extrusion Process ◽  
Slow Cooling ◽  
Hybrid Heating ◽  
Elongation Viscosity ◽  
Ir Heating ◽  
Material Stiffness ◽  
The Difference

FDM printing is based on resistance to heat of the polymer filament, which starts in a viscous state and is extruded from nozzle to the printing area. The printing area is hot around 70°C for a better adherence of the deposited polymer and for slow cooling of it. The later deposited layers will experience faster cooling and the characteristics of the polymer will suffer light changes. The paper aims to present the results of a preliminary research regarding the double source successive heating and double source hybrid heating of the extruded polymer in FDM process. There were used two distinct heat sources, the resistive source mounted in the extrusion nozzle and IR lamp heat source placed in the printing chamber. The first heating, which acts during the extrusion process, is a hybrid heating and it is developed inside the extrusion nozzle (hot-end); it is given by the resistive heat source by the IR lamp. After the extrusion, during the deposition process and after the deposition process, the heating of the polymer continues due to the IR lamp. The difference between the printing with IR heating and without IR heating was monitored. A decreasing of about 5-8% of the material stiffness was noticed when the IR lamp was introduced. The material became more viscous and the bonding of the successive layers was improved. DSC analysis has been performed in both cases: with and without IR heat source. The evolution of the elastic modulus proved a decreasing of the plasticity during the simple printing process. The decreasing was less (at least by about 25%) when used IR heat source. The elongation viscosity was analysed and its values were decreasing while the temperature was increasing that took place. The decreasing was produced by the reduction of the elasticity, when the chain branches were decreasing their length. The decreasing is more pronounced while the increasing of the temperature. A low difference (of about 2-5%) was observed to the mechanical characteristics after tensile tests.

scholarly journals Study of the Ultraviolet Effect and Thermal Analysis on Polypropylene Nonwoven Geotextile

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1080
Author(s):  
Clever Aparecido Valentin ◽  
Marcelo Kobelnik ◽  
Yara Barbosa Franco ◽  
Fernando Luiz Lavoie ◽  
Jefferson Lins da Silva ◽  
...  
Keyword(s):  
Uv Light ◽  
Polymeric Materials ◽  
Tensile Tests ◽  
Thermomechanical Analysis ◽  
Material Stiffness ◽  
Before And After ◽  
Electron Microscopy Analysis ◽  
Physical Tests ◽  
Nonwoven Geotextile

The use of polymeric materials such as geosynthetics in infrastructure works has been increasing over the last decades, as they bring down costs and provide long-term benefits. However, the aging of polymers raises the question of its long-term durability and for this reason researchers have been studying a sort of techniques to search for the required renewal time. This paper examined a commercial polypropylene (PP) nonwoven geotextile before and after 500 h and 1000 h exposure to ultraviolet (UV) light by performing laboratory accelerated ultraviolet-aging tests. The state of the polymeric material after UV exposure was studied through a wide set of tests, including mechanical and physical tests and thermoanalytical tests and scanning electron microscopy analysis. The calorimetric evaluations (DSC) showed distinct behaviors in sample melting points, attributed to the UV radiation effect on the aged samples. Furthermore, after exposure, the samples presented low thermal stability in the thermomechanical analysis (TMA), with a continuing decrease in their thicknesses. The tensile tests showed an increase in material stiffness after exposition. This study demonstrates that UV aging has effects on the properties of the polypropylene polymer.

scholarly journals Tensile Testing with Cyclic Strain Holding to Analyze Dynamic Recrystallization of Pure Lead

2014 ◽  
Vol 2014 ◽  
pp. 1-8
Author(s):  
Mayu Muramatsu ◽  
Motomichi Koyama ◽  
Ikumu Watanabe
Keyword(s):  
Dynamic Recrystallization ◽  
Tensile Testing ◽  
Cyclic Strain ◽  
Tensile Tests ◽  
Pure Lead ◽  
Factors Affecting ◽  
Before And After ◽  
Dynamic Recrystallization Behavior ◽  
The Difference ◽  
Strain Responses

We analyzed the dynamic recrystallization of pure lead by tensile testing with cyclic strain holding at room temperature. The specimens were held at an identical strain and subsequently reloaded, providing the strength before and after the strain holding process. The difference in strength enables factors affecting dynamic recrystallization behavior to be analyzed through mechanical testing. For instance, the effects of strain rate on dynamic recrystallization were analyzed by comparing the results obtained from tensile tests with and without strain holding. This experimental technique demonstrated some parts of contribution of elastic strain, dynamic recovery, dynamic recrystallization, and necking to stress-strain responses.

Effects Of Gettering On Device Characteristics

1996 ◽  
Vol 442 ◽  
Author(s):  
Mitsuhiro Horikawa ◽  
Akihiko Yaoita ◽  
Tsuyoshi Nagata ◽  
Tomohisa Kitano
Keyword(s):  
Heat Treatment ◽  
State Of The Art ◽  
Annealing Process ◽  
Clean Room ◽  
Data Retention ◽  
Effective Technique ◽  
Slow Cooling ◽  
Metal Impurities ◽  
The Difference ◽  
Metallic Impurities

AbstractEffective methods of gettering metallic impurities were proposed. To achieve effective gettering, an annealing process to induce gettering was modified taking fundamental gettering steps and the difference in the gettering mechanism into account. As the concentration of heavy metal is below solubility in a state-of-the-art clean room, a combination of segregation type gettering and slow cooling heat treatment is an effective technique to remove metal impurities from the device active region. Using this technique, DRAM device characteristics such as leakage current and data retention time can be improved.

scholarly journals Spark Plasma Diffusion Bonding of TiAl/Ti2AlNb with Ti as Interlayer

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3300
Author(s):  
Boxian Zhang ◽  
Chunhuan Chen ◽  
Jianchao He ◽  
Jinbao Hou ◽  
Lu Chai ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Base Metal ◽  
Diffusion Bonding ◽  
Energy Dispersive Spectrometer ◽  
Tensile Tests ◽  
Slow Cooling ◽  
Ti2alnb Alloy ◽  
Heat Treated ◽  
Plasma Diffusion ◽  
Spark Plasma

To solve the problem of poor weldability between TiAl-based and Ti2AlNb-based alloys, spark plasma diffusion bonding was employed to join a TiAl alloy and a Ti2AlNb alloy with a pure Ti foil as interlayer at 950 °C/10 KN/60 min. After welding, slow cooling was carried out at a rate of 5 °C/min, followed by homogenization at 800 °C for 24 h. The microstructural evolution and elemental migration of the joint were analyzed via a scanning electron microscope equipped with an energy dispersive spectrometer, while the mechanical properties of the joint were assessed via microhardness and tensile tests. The results show that the spark plasma diffusion bonding formed a joint of TiAl/Ti/Ti2AlNb without microcracks or microvoids, while also effectively protecting the base metal. Before heat treatment, the maximum hardness value (401 HV) appeared at the Ti2AlNb/Ti interface, while the minimum hardness value (281 HV) occurred in the TiAl base metal. The tensile strength of the heat-treated joint at room temperature was measured to be up to 454 MPa, with a brittle fracture occurring in the interlayer. The tensile strength of the joint at 650 °C was measured to be up to 538 MPa, with intergranular cracks occurring in the TiAl base metal.

Effect of temperature on the biaxial mechanics of excised lung parenchyma of the dog

1992 ◽  
Vol 73 (3) ◽  
pp. 1171-1180 ◽  
Author(s):  
J. C. Debes ◽  
Y. C. Fung
Keyword(s):  
Mechanical Properties ◽  
Lung Parenchyma ◽  
Tensile Tests ◽  
Stretch Ratio ◽  
Effect Of Temperature ◽  
Uniaxial Tensile ◽  
Slow Cooling ◽  
Influence Of Temperature On ◽  
Creep And Stress Relaxation ◽  
Tissue Material

The influence of temperature on the mechanical properties of excised saline-filled lung parenchyma of the dog was studied at low lung volume. The motivation of this study was to determine whether lung tissue material without the influence of surface tension undergoes a phase transition in the 20–40 degrees C range, as does synthetic elastin studied by Urry in 1984–1986. Dynamic biaxial and uniaxial tensile tests were done, and strain vs. Lagrangian stress curves were recorded during slow cooling and heating between 40 and 10 degrees C. To emphasize the effects of elastin, strains (defined as stretch ratio minus one) were kept below 30%. A slight decrease in compliance occurred with cooling over the entire temperature range. This effect may be attributed to collagen. It was accompanied by a gradual increase in length as the tissue cooled, an effect that may be attributed to elastin. This process was partially reversible with reheating. However, this effect is in contrast with the sudden drastic change in mechanical properties of synthetic elastin described by Urry. Hysteresis, creep, and stress relaxation were small at these low strains. Possible causes of these effects are discussed.

Stress in Titanium Disilicide Layers, During and After Formation.

1988 ◽  
Vol 130 ◽  
Author(s):  
J. F. Jongste ◽  
F. E. Prins ◽  
G. C. A. M. Janssen ◽  
S. Radelaar
Keyword(s):  
Silicon Substrate ◽  
Semiconductor Device ◽  
Linear Thermal Expansion ◽  
Deposition Process ◽  
Device Fabrication ◽  
Titanium Disilicide ◽  
Titanium Layer ◽  
Thermal Expansion Coefficients ◽  
The Difference ◽  
Interconnect Lines

AbstractDuring and after formation of a thin layer of titanium disilicide (TiSi2) on a silicon substrate stress is caused in several ways: Intrinsic stresses are due to the deposition process or to phase transformations and grain growth of the deposited material. Extrinsic stresses are caused by thermal effects: the difference in linear thermal expansion coefficients of the layer and the substrate respectively. Problems related to stresses can occur in semiconductor device fabrication. Stresses can deteriorate gate oxides in MOSFETs and can cause cracks in interconnect lines. Also, focusing problems in lithographic steps can occur because of wafer warpage. In this paper some examples of the different types of stress that can occur are shown and discussed. Both multilayer and self aligned Ti-Si samples have been studied: The advantage of the use of Ti-Si multilayers to produce TiSi2 is that diffusion has to proceed only over a short distance i.e., the multilayer period. So the annealing time can be short. In the self aligned silicidation process, where a layer of a titanium layer on top of a silicon substrate is annealed, the diffusion length is equal to the thickness of the Ti layer. Because longer annealing times are needed, the latter type is used to monitor stress during formation.

scholarly journals Development of a novel high straining backward extrusion process

2018 ◽  
Vol 190 ◽  
pp. 06001 ◽  
Author(s):  
Qiang Wang ◽  
Zhimin Zhang ◽  
Xubin Li ◽  
Huifang Zhang
Keyword(s):  
Flow Direction ◽  
Effective Strain ◽  
Fibrous Tissue ◽  
Axial Direction ◽  
Extrusion Process ◽  
Backward Extrusion ◽  
New Process ◽  
Processed Sample ◽  
The Difference ◽  
Low Performance

In this study, a new method of backward extrusion is proposed. In this new process, a punch with a movable mandrel was designed. A hollow billet was firstly backward extruded and subsequently upset with the use of the punch after the mandrel returned. The extrusion and upsetting processes were successively executed in order for a higher effective strain to be imposed and a fibrous tissue flow direction to be controlled. In order for the capability of this process to be investigated, experimental and finite element (FE) methods were used. The effective strain of the final part prepared by both the conventional and the new process were compared along the bottom radial and wall axial direction respectively. In the results, it is shown that the plastic strain applied through the processed sample was approximately higher in twice the value of the sample processed via conventional backward extrusion. Consequently, this may improve the mechanical properties and anisotropy of the final products. The difference of the UTS and the TYS between radial and tangential at the bottom was less than 3%.This new process has proven to be promising for parts with a central hole at the bottom production in order for the parts low performance to be improved.

Natural Convective Characteristics of an Oblique Heat Source Module in the Closed and Ventilated Cabinets

2010 ◽  
Author(s):  
Yeong-Ley Tsay ◽  
Jen-Chieh Cheng ◽  
Yong-Lin Zhuang
Keyword(s):  
Heat Source ◽  
Hot Spot ◽  
Velocity Fields ◽  
Thermal Interaction ◽  
Surrounding Area ◽  
The Difference ◽  
Conjugate Conduction ◽  
Temperature And Velocity Fields ◽  
Air Streams ◽  
Spot Temperature

A numerical analysis is performed to study the characteristics of heat transfer from a block heat source module at different angles in two-dimensional cabinets. Great efforts are carried out to conduct the effects of thermal interaction between the air steams inside and outside the cabinet on the conjugate conduction–natural convection phenomena. Moreover, the enhancement of cooling performance of the heat source module through the construction of air vents on cabinet wall is rigorously examined. The computation domain covers the cabinet and the surrounding area, and the temperature and velocity fields of the cabinet and surrounding area are solved simultaneously. Results show that the thermal interaction between the airs inside and outside the cabinet, the module angle and vent position can significantly affect the transfer characteristics. Comparing the results for cases with and without the consideration of thermal interaction between the air streams, the difference in hot spot temperature of module can be up to 26% for Pr = 0.7, Kbf = Kpf = Kwf = 100, 105 ≦ Ra ≦ 107 and φ = 0°, 90°, 270°. The maximum reduction in hot spot temperature is about 41% when two air vents are constructed on cabinet wall. The variation of module angle results in the maximum difference of the hot spot temperature is 15% for closed cabinet, and 10% for ventilated cabinet.

scholarly journals Influence of glass beads filler and orientation process on piezoelectric properties of polyethylene composites

2019 ◽  
Vol 30 (24) ◽  
pp. 21032-21047 ◽  
Author(s):  
Halina Kaczmarek ◽  
Marta Chylińska ◽  
Bogusław Królikowski ◽  
Ewa Klimiec ◽  
Dagmara Bajer ◽  
...  
Keyword(s):  
Piezoelectric Properties ◽  
Tensile Tests ◽  
Extrusion Process ◽  
Glass Beads ◽  
Mechanical Resistance ◽  
Scanning Calorimetry ◽  
Crystallinity Degree ◽  
X Ray ◽  
Polyethylene Composite ◽  
Polyethylene Composites

AbstractThe effect of silica filler (in the form of glass beads) on polyethylene composite properties has been studied. Conditions for obtaining polyethylene-based composites in the extrusion process were developed. Two types of such composites were prepared: non-oriented and oriented in the uniaxial stretching process in a ratio of 3:1. The morphology, microstructure (including crystallinity degree), mechanical resistance, and thermal stability of the obtained composites containing 2.5–10% of the filler were analyzed by the scanning electron microscopy connected with energy dispersive X-ray analysis, X-ray diffraction, differential scanning calorimetry, thermogravimetry methods, and tensile tests. In order to induce piezoelectric effect, the samples were charged with a direct current of 100 V/μm at 85 °C. The piezoelectric properties of the polyethylene composites were determined by the measurement of charge and voltage of current generated during action of stress up to 120 kPa. Piezoelectric coefficients, d33 and g33, versus applied stress were determined and the stability of electrets stored during 2–5 months was tested too. The best piezoelectric properties were found for medium-density polyethylene composite containing 5% of glass beads.

scholarly journals Effect of Carbon Nanotubes (CNT) Functionalization and Maleic Anhydride-Grafted Poly(trimethylene terephthalate) (PTT-g-MA) on the Preparation of Antistatic Packages of PTT/CNT Nanocomposites

2020 ◽  
Vol 4 (2) ◽  
pp. 44 ◽  
Author(s):  
Natália Ferreira Braga ◽  
Henrique Morales Zaggo ◽  
Larissa Stieven Montagna ◽  
Fabio Roberto Passador
Keyword(s):  
Carbon Nanotubes ◽  
Maleic Anhydride ◽  
Interfacial Adhesion ◽  
Morphological Analysis ◽  
Electrostatic Discharge ◽  
Electronic Devices ◽  
Tensile Tests ◽  
Extrusion Process ◽  
Agent Based ◽  
Trimethylene Terephthalate

Electronic devices require the use of antistatic packing to prevent electrostatic discharge during their storage or transport. Poly (trimethylene terephthalate) (PTT) is a polyester with excellent properties and can be a good candidate for this application. To make this insulating polymer an extrinsic conductor, carbon nanotubes (CNT) can be added to reduce the electrical resistivity of the nanocomposites. In order to facilitate the CNT distribution on polymeric matrix, it was proposed a chemical functionalization using nitric acid for the creation of functional groups on its surface. Moreover, the PTT matrix was modified with a compatibilizer agent based on maleic anhydride grafted PTT (PTT-g-MA), to improve interfacial adhesion between the nanofiller and matrix. In this work, nanocomposites based on PTT/PTT-g-MA/CNT were prepared by extrusion process, with 0.5 wt% and 1.0 wt% of CNT and functionalized CNT. CNT was characterized by stability dispersion in water, Raman spectroscopy, FTIR and XPS analysis, which prove the success of functionalization. The nanocomposites were evaluated by thermal analysis, tensile tests, electrical conductivity, and morphological analysis. The CNT functionalization and the addition of PTT-g-MA increased the dispersion and distribution of CNT in the PTT matrix. The electrical properties show that this material can be used as an antistatic packaging.

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