Glass Powder Additive on Recycled Polypropylene Filaments: A Sustainable Material in 3D Printing

This study aimed to characterize the effect of a glass powder additive on recycled polypropylene (rPP) materials from food packaging to be used as filaments in material extrusion (MEX) 3D printing applications. The composite filaments studied were rPP filaments with glass powder (GP) additive in the 2.5%, 5%, and 10% fractions. As a baseline, the filaments made of pure virgin PP and rPP without additive were used. The filament that has been successfully made is then printed into a tensile test specimen and an impact test to observe its mechanical properties. Fourier-transform infrared spectroscopy (FTIR) characterization was also carried out to determine the effect of chemical bonding and thermal characterization using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The results of FTIR characterization on the sample rPP + 10% do not show a typical peak shift of PP, but give rise to new peaks at wavenumbers of 1000 cm−1 (Si-O-Na), 890 cm−1 (Si-H) and 849 cm−1 (O-Si-O), which indicate the typical peaks of the glass constituent compounds. In the thermal characteristics, the addition of GP shows the improved stability of mass changes to heat and increases the melting temperature of rPP. The ultimate tensile strength and Young’s modulus for rPP-based specimens with 10% GP additive showed an increase of 38% and 42% compared to PP specimens. In addition to the improved mechanical strength, the addition of GP also reduces the bending deformation, which can be well controlled, and reduces curvature, which is a problem in semicrystalline polymer-based filaments.

Development mechanical and fatigue properties of AA7001 after combined SP with deep cryogenic treatment and UIP with deep cryogenic treatment

Al alloys have long been of interest to the aerospace community, due to their modest specific strength, ease of manufacture, and low cost. In recent years, with the rapid development of weaponry, 7XXX ultra-high strength aluminum alloys used increasingly in military fields. Chemical analysis of the AA 7001 is supported out at The Company State for Engineering, Rehabilitation and Inspection (SIER) in Iraq. Strengthening the surface (shot penning) is beneficial to delay crack nucleation and extend life. The test samples (tensile and fatigue) are subject to the SP process by using ball steel with the parameters (Pressure=12 bars, Speed=40 mm/min, Distance=150 mm, Shot size=2.25 mm, Coverage=100 %). The ultrasonic impact treatment (UIP) machine is used for enhancing the surface properties. For the Deep Cryogenic Treatment (DCT), the samples have been placed in the cooling chamber. A standard tensile test specimen is prepared in a round section with the dimensions chosen according to ASTM (A370-11). Tensile and fatigue of rotating bending with R=–1 have been conducting, after the effect of deep cryogenic treatment (DCT), combined shot peening (SP+DCT), and ultrasonic impact peening (UIP+DCT) of AA7001 have been examining. The maximum improvement percent in ultimate tensile strength (UTS) due to (DCT), (SP+DCT), and (UIP+DCT) were about 3 %, 8.27 %, and 6.25 %, respectively. The rise in the yield stress due to (DCT), (SP+DCT), and (UIP+DCT) were 9.5 %, 14.6 %, and 13.14 %, respectively. The ductility reduced by constituents of 8.57 %, 12.5 %, and 11.42 % sequentially. The improvement in fatigue strength in a high cycle regime is 16 % for (SP+DCT) due to combined effects, it is an 8 % increase in the endurance limit on fatigue behavior due to inducing compressive residual stress (CRS)

Prediction of Tensile Strength of 3D Printed Bronze PLA Part Using Response Surface Modelling

Background - 3D printing is a dynamic process with many process parameters influencing the product, including the type of the material; it is often difficult to understand the combined influence of these parameters. Purpose - The tensile strength of 3D printed parts is important for the functionality of components. The effects of process parameters on tensile strength must therefore be examined. The objective of this study is to develop a response surface model (RSM) to predict the final quality of a 3D printed bronze part from a different set of input parameters. Methods - The tensile test specimen was built in a Makerbot 3D printer with bronze polylactic acid (PLA) material. The three controllable input parameters were; thickness of layers, number of shells, and infill density. The three levels of layer thickness were 0.1mm, 0.2mm and 0.3mm. The number of shells was 2, 3 and 4. The infill densities were 20%, 30% and 40%. A tensile experiment tested the strength of the specimens. RSM is a statistical approach for modelling and analyzing how different variables affect the response of interest, and for optimizing it. Results - The result obtained shows that the specimen with a high layer thickness of 0.3mm and infill density of 40% is the best among all the other parameters. Finally, the regression equation produced was used for random values of layer thickness, the number of shells, and infill density, to see whether the values obtained from the tests fall into the range of experimental data. Conclusion - Infill density and layer thickness are the two criteria that significantly influence the tensile property. The number of shells has the least influence on the tensile property. However, the best tensile strength is the part printed with higher infill density, a greater number of shells, and higher layer thickness.

Pembuatan dan Pengujian Papan Komposit (Composite Board) Dari Limbah Kantong Plastik (Kantong Kresek)

Abstrak Pada penelitian ini akan diteliti proses pembuatan papan komposit (Composite Board) dengan metode pemasan menggunakan media minyak goreng. Papan komposit yang dibuat ada 4 spesimen yaitu papan komposit tanpa bahan pengisi dan papan komposit dengan bahan pengisi. Bahan pengisi menggunakan serat alam yaitu serat bambu, serat kelapa dan serat ijuk. Berdasarkan hasil pengujian bending didapat hasil kekuatan bending untuk spesimen 1 (tanpa serat) 393,283 N, spesimen 2 (dengan serat bambu) 128,627 N, spesimen 3 (dengan serat kelapa) 260,627 N dan spesimen 4 (dengan serat ijuk) 477,785 N. Berdasarkan hasil pengujian tarik didapat hasil kekuatan tarik untuk spesimen 1 (tanpa serat) 524,475 N, spesimen 2 (dengan serat bambu) 523,687 N, spesimen 3 (dengan serat kelapa) 464,399 N, spesimen 4 (dengan serat ijuk) 387,361 N. Secara garis besar papan komposit dengan bahan pengisi serat ijuk mempunyai kekuatan mekanis yang lebih baik di bandingkan papan komposit spesimen lainnya. Kata kunci: Limbah Plastik, Kantong Plastik, Kantong Kresek, Komposit, Serat Alam,Daur ulang. Abstract This research will examine the process of making a composite board with the heating method using cooking oil as a heating media. There are 4 specimens are made of composite boards and it divided into two category, such as composite boards with fillers and composite boards without fillers. Fillesr which are used in composite boards is a natural fiber, namely bamboo fiber, coconut fiber and palm fiber. Based on the results of the bending test, specimen 1 (without fibers) obtained the bending strength of 393,283 N, specimen 2 (with bamboo fibers) of 128,627 N, specimen 3 (with coconut fiber) of 260,627 N and specimen 4 (withpalm fiber) of 477,785 N. Based on the results of the tensile test, specimen 1 (withoutfibers) obtained tensile strength of 524,475 N, specimen 2 (with bamboo fibers) of 523,687 N, specimen 3 (withcoconut fiber) of 464,399 N, and specimen 4 (with palm fiber) of 387,361 N. Generally, the composites board with palm fiber as a filler materials have better mechanical strength than other specimen composite boards. Keywords: PlasticWaste, Plastic, PlasticBags, Composites, Natural Fibers, Recycle

Investigations on Mechanical Properties of Carbon and Glass Fiber Composites with Titanium Oxide and Silicon Dioxide Filler

The utilization of carbon and glass fiber composites is very extensive in the fields of aviation and automobiles. The strength to weight fraction of these composites is immense. Even though, the modern applications require a lot of improvement in strength. The addition of Nano fillers had brought about significant changes in mechanical properties of the composites. The present work aims at finding out the effects on mechanical properties of composites due to the addition of titanium oxide 10% + silicon dioxide 10% hybrid filler. Hand layup process is used for the fabrication of tensile and flexural test specimens which are prepared as per the ASTM standards. The tensile test specimen is D-638 type-iv and the flexural specimen is D-790. Epoxy is used as resin and forms the matrix whereas the carbon and glass fibers act as reinforcement. The comparison is made between the specimens with and without hybrid filler. Two specimens of each type are prepared to have repeatability. The tensile and flexural tests are carried on universal testing machine (UTE-10) and results were obtained. The results showed a significant improvement in tensile and flexural strengths of carbon composites and only flexural strength in glass fibers with hybrid filler.

The effect of fibre treatment on water absorption and mechanical properties of buri palm (Corypha utan) fibre reinforced epoxy composites

Over the past century, there has been a dramatic increase in natural fibre composites in which natural fibre has served as reinforcement in polymer. However, the existence of moisture and defects in natural fibres has impacted the mechanical and physical properties of natural fibre polymer composites. The main objective of this study is to fabricate the buri palm fibre reinforced epoxy composite and evaluate the effects of fibre treatment on water absorption and tensile properties. The buri palm fibre were treated by using 5 wt.% NaOH for 24 h and the laminated composite of untreated and treated four-layer and five layer fibres were fabricated via hand lay-up process. The tensile specimens are prepared according to the ASTM D638 standard and the water absorption experiment was conducted by immersing the specimen in distilled water at room temperature until it reached the saturated moisture absorption. The results revealed that the percentage of moisture uptake was reduced to 69% and 95% in treated four-layer and five-layer sequences. It is observed that the thickness swelling of the composite increased with the increase of sequence layering, while the thickness swelling decreased with treated fibre. Alkali treatment affected the properties of buri palm fibre which improved the interfacial bonding between the fibre and epoxy matrix for better tensile properties and reduced water absorption. Finally, morphology examinations were carried out to analyse the fracture behaviour and fibre failure on the tensile test specimen by using microscope analysis.

Optimal Extrusion Die Design for Production of Polymer Tensile Test Specimen

This work aims to present the design of an extrusion die for the production of polymeric tensile test specimens. Computational Fluid Dynamics is used during the optimization process to minimize the overall pressure drop across the die, achieve uniform exit velocity, low energy consumption, high throughput, and excellent properties of the extruded specimens. A three-dimensional incompressible viscous flow is considered and the Cross model is employed for taking into account the non-Newtonian behavior of the flow. Several geometries are analyzed before devising an optimum shape. The final design includes, in the beginning, a conical flow profile and then it gradually transitions into the rectangular cross-section of the slab. The die land is an elongated flow restriction channel of smaller cross-section, where the material experiences gradually-decreasing pressures along the length of the land and finally converging the molten polymer into a melt laminate at the exit.

Microstructural Evolution and Fracture Mechanism for Scar Defect Formation on Advanced High Strength Steel during a Shearing Process

To form a required shape of the advanced high strength steels especially DP steel sheets, shearing process being one of major processes is commonly used. In general, although the good cut-edge with small fracture could be achieved by setting small shearing clearance, the tearing being a major defect commonly occurred on the cut-edge. Therefore, in the present research, a tearing mechanism on the DP steel sheet, grade SPFC980Y (JIS) during shearing process is investigated and clearly clarified based on the microstructure evolution, fracture mechanism, and stress distribution analysis. The microstructure evolutions on both tensile test specimen and sheared workpiece were performed to clarify the fracture mechanism. The angle between shear band and elongated grain flow direction is examined based on tensile test and it is used to predict an angle of initial fracture and its propagation on the shearing process as well. By associated with stress distribution analysis generated in shearing zone during shearing phase, the results revealed that the fracture propagated out of shearing zone and the fracture could be easily delayed. This resulted in that the tearing could be generated in the case of SPFC980Y. Vice versa, the fracture propagation is all in shearing zone, the fracture could not be delayed and the fracture completely generated on the cut-edge in the case of SPCC. In the present resents, the tearing mechanism on the DP steels in shearing process is clearly characterized.

Optimization of Welding Parameters and Microstructure and Fracture Mode Characterization of GMA Welding by Using Taguchi Method on SS304H Austenitic Steel

This study is centre on optimizing different welding parameters which affect the weldability of SS304H, Taguchi technique was employed to optimize the welding parameters and fracture mode characterization was studied. A number of experiments have been conducted. L9 orthogonal array (3×3) applied for it. Analysis of variance (ANOVA) and signal to noise ratio (SNR), a statistical technique was applied to determine the effect of different welding parameters such as welding current, wire feed speed and gas flow rate on weldability of SS304H. Tensile strength, toughness, micro hardness and mode of fracture was examined to determine weldability of SS304H and it was observed from result that welding voltage have major impact whereas gas flow rate has minour impact on ultimate tensile strength of the welded joints and optimum process parameters were found to be 23 V, 350 IPM travel speed of wire and 15 l/min gas flow rate for tensile strength and mode of fracture was ductile fracture for tensile test specimen.