Performance evaluation of different types of graphite electrodes on titanium (Ti - 6A1 - 4V)

This thesis presents the EDMing of Titanium (Ti-6A1-4V) using POCO EDM 3 and POCO EDM C3 graphites electrodes with diameter of 10 mm. The main purpose of this study was to investigate the influenced of various parameters involved in EDM on the machining characteristics, namely, material removal rate (MRR), electrode wear ratio (EWR), surface roughness (Ra), recast layer (RL) and heat affected zone (HAZ) after undergone EDMing process and to compare the performance of both electrodes. The Full Factorial Design of Experiment (DOE) approach with two-level was used to formulate the experimental layout, to analyze the effect of each parameter such as pulse on (ON), pulse off (OFF), peak current (IP) and servo voltage (SV) on the machining characteristics EDM . In this investigation, the machining operation for titanium was performed using a Sodick linear motor EDM sinker series AQ55L. Meanwhile, for the measurement equipments; Mitutoyo Surftest SJ-400 was used to measure the surface roughness, and the thickness of recast layer and heat affected zone were examined using the Scanning Electron Microscope XL40. In general, results revealed that pulse on (ON) and peak current (IP) have appeared to be the most significant effect to all responses investigated. In term of performance, POCO C3 gives better material removal rate (MRR) value compare to POCO 3 but in term of electrode wear ratio (EWR) and also surface roughness (SR) POCO 3 gives better result compare to POCO C3. On the Recast layer and HAZ both the good and the worst came from POCO 3. The lowest recast layer achieved was 13.5 fxm and the lowest HAZ achieved was 12.7 Hm. Confirmation tests were also conducted for the optimum conditions for each machining characteristics in order to verify and compare the results from the theoretical prediction using Design Expert software and experimental confirmation tests. Overall, the results from the confirmation tests showed that the percentage of performance was acceptable due to all the results obtained were within the allowable values which was less than 15% of margin error

Assessment of residual strength of corrosion damaged concrete structures

The corrosion of steel reinforcement in concrete is one of the major problems with respect to the durability of reinforced concrete structures. In addition, the residual strength of concrete with corroded reinforcement is much debated. This is because many parameters are implicated when assessing reinforcement corrosion, such as by using the percentage of loss of bar area, percentage of mass loss, reduction of bar radius, percentage of corroded area in the overall beam, and the width of the surface crack. The aim of the current study is to integrate correlations between deterioration and strength degradation into a systematic methodology for estimation of the residual strength of concrete structures based on their serviceability limit state. In the numerical analysis, the objective is to understand the effects of corrosion expansion on the behaviour of surface crack width. Results from the numerical study are used to determine parameters for the experimental investigation. The experimental approach is used to assess the influence of corrosion parameters, which are quantified as a percentage of the section loss, radius loss or corrosion penetration, and crack width on the residual bond strength based on different bar locations, casting positions, and impressed currents. Results from the experimental analyses show that the corrosion level on the main reinforcing bar in this study cannot be used as an indicator in assessing the residual bond strength due to many factors consideration during the assessment. However, corrosion-induced crack width on the bottom cast correlated well with residual bond strength. When crack width increased, most of the bar had a lower residual bond strength value

The Machinability Performance of RBD Palm Oil Dielectric Fluid on Electrical Discharge Machining (EDM) of AISI D2 Steel

Electrical discharge machining (EDM) is a high-precision manufacturing process that may be implemented to any electrically conductive material, notwithstanding its of mechanical residences. It’s far a non-contact process using thermal energy that is used in a wide range of applications, especially for difficult-to-cut materials with complicated shapes and geometries. The dielectric is critical in this process as it focuses the plasma channel above the processing and also serves as a debris carrier. The long-term use of dielectric used in EDM process pollutes to the atmosphere and is harmful to the operator's health. This study compares the efficiency of refined, bleached, and deodorized (RBD) palm oil (cooking oil) with traditional hydrocarbon dielectric, kerosene using copper electrode in the finishing process of AISI D2 steel. Low peak current, Ip 1A to 5A and pulse duration, ton up to 150μs were chosen as the main parameters. The effects of material removal rate (MRR), electrode wear rate (EWR), and surface roughness (Ra) were evaluated. The result shows that RBD palm oil has higher MRR which is 33.4821mm3/min while kerosene is 22.4888mm3/min, both at Ip=5A and ton=150µs. The improvement when RBD palm oil is used as dielectric is 48.88% compared to kerosene. With the increase in peak current, the EWR increases but it is inversely proportional to the pulse duration. The lowest EWR is obtained at the same IP=1A and ton=150µs for both RBD palm oil and kerosene which is 0.0010mm3/min and 0.0002mm3/min respectively. The minimum value of Ra for RBD palm oil is 2.15µm at IP=1A and ton=150µs, while for kerosene it is 2.11µm at IP=1A and ton=150µs. In terms of finishing process efficiency, RBD palm oil, a biodegradable oil-based dielectric fluid, has shown significant potential in EDM processing of AISI D2 steel

Impact test and bioactivity properties of polycaprolactone (PCL) by addition of nano-montmorillonite (MMT) and hydroxyapatite (HA)

This report described the Impact Test result and Bioactivity Properties of biodegradable Polycaprolactone (PCL) blend with nano- Montmorillonite (MMT) and Hydroxyapatite (HA). The amount of nano-MMT is varies from 2 to 4 by weight % meanwhile the amount of HA is fixed to 10 by weight percentage (wt%). The addition of nano-MMT and HA filler is to tune and indirectly improve the mechanical and bioactive properties of PCL. The samples for these test are injected from injection molding machine. The Impact test are conducted using Charpy Method. From the analysis it is found that the toughness of PCL are decreased by the addition of these fillers. PCL/MMT composites gives a better result compare to PCL/MMT/HA composites. This is due to the HA characteristic which is brilttle and tends to reduce the ductile properties of the polymer. From the Simulated Body Fluis (SBF) result, formation of apatite layer at the surface of the composites is evidence of excellent bioactivity properties of HA. The enhance of bioactivity has been proved while incorporation of HA into PCL/MMT composite. SEM-EDX image showed the bulk formation of apatite layers on the composite surface with 10 wt% HA after 3 days immersed in SBF solution

Mechanical Properties of PCL/PLA Composite Sample Produce from 3D Printer and Injection Molding

Currently there are a lot of studies have been carried out regarding on composite material that can be used for 3D printing. The main reasons is to minimize the cost related to the molds that need to be prepared for injection molding. The question is how far will be the differences in term of mechanical properties for part produce from this 2 techniques. This study are done to investigate the mechanical properties of PCL/PLA composite sample prepared from Fused Deposition Modelling (FDM) 3D printer. The mechanical properties that were evaluated are tensile, flexural and impact. The result were later compared with samples produced from injection molding. The dimensional accuracy result shows a very minimal percentage error on samples produced using 3D printer for mechanical testing. The parameter of 3D printer used to produce sample was 136°C print temperature, 0.12mm deposition of height, 20mm/s print speed and 22mm/s travel speed. The mechanical properties of PCL/PLA prepared by injection molding generally came superior in all the conducted test if compared to those of 3D printer. Tensile strength result showed that injection molding value was higher than 3D printer which is 10MPa and 6.513MPa respectively. The results of tensile strength and modulus of elasticity showed injection molding ware better than 3D printing with value of 118.26MPa and 61.223MPa respectively. For flexural strength, the highest values were injection molding which is 7.59MPa while 3D printing is 4.96Mpa. While the highest for flexural modulus are 35.33GPa for injection molding and 30.911GPa for 3D printing. Impact strength for PCL/PLA sample was 1.33 Joule for injection molding and 0.543 Joule for 3D printer method

What Key Drivers Are Needed To Implement Material Efficiency Strategies? An Analysis Of The Electrical And Electronic Industry In Malaysia And Its Implications To Practitioners

A circular economy can be achieved by the efficient use of materials across different industries and sectors. In the manufacturing sectors, practicing material efficiency is one of the effective strategies to reduce material usage and solid waste generation. However, due to many unknown factors, such as key drivers to enhance material efficiency, most of the time, manufacturers are practicing at the minimum level of material saving. This study aims to examine the key drivers of material efficiency among electrical and electronic (E&E) companies to fulfill the aims of sustainable manufacturing. The data collection and synthesis were conducted using semi-structured interviews and an analytical hierarchy process survey. In this study, thirteen key drivers were found. Five internal drivers and eight external drivers with different priorities were found to influence E&E companies in the practice of material efficiency strategies. In addition, the drivers’ implications to different practitioner groups are suggested. To conclude, achieving material efficiency can be done effectively if the incentivized key drivers are clearly notified. This research is important to show the key drivers that influence the implementation of material efficiency strategies in the E&E industrie

EFFECT OF ZINC DOPED CALCIUM PHOSPHATE THROUGH MECHANOCHEMICAL SYNTHESIS

ABSTRACT In this research, zinc was doped into calcium phosphate through mechanochemical synthesis. Zinc mol concentration was varied from 0.1%, 0.3% and 0.5%. The main precursors employed in this work are calcium hydroxide, phosphoric acid and zinc hydroxide. The synthesized powders were examined through FTIR and XRD analyses to validate the presence of all the chemical elements. The synthesized powders were then compacted into green bodies and sintered at 1000 o C. Density test showed a linear change towards the different concentration on the zinc where zinc dopants improved the densification and microstructure of the calcium phosphate

The Machinability Performance of RBD Palm Oil Dielectric Fluid on Electrical Discharge Machining (EDM) of AISI D2 Steel

Electrical discharge machining (EDM) is a high-precision manufacturing process that may be implemented to any electrically conductive material, notwithstanding its of mechanical residences. It’s far a non-contact process using thermal energy that is used in a wide range of applications, especially for difficult-to-cut materials with complicated shapes and geometries. The dielectric is critical in this process as it focuses the plasma channel above the processing and also serves as a debris carrier. The long-term use of dielectric used in EDM process pollutes to the atmosphere and is harmful to the operator's health. This study compares the efficiency of refined, bleached, and deodorized (RBD) palm oil (cooking oil) with traditional hydrocarbon dielectric, kerosene using copper electrode in the finishing process of AISI D2 steel. Low peak current, Ip 1A to 5A and pulse duration, ton up to 150μs were chosen as the main parameters. The effects of material removal rate (MRR), electrode wear rate (EWR), and surface roughness (Ra) were evaluated. The result shows that RBD palm oil has higher MRR which is 33.4821mm3/min while kerosene is 22.4888mm3/min, both at Ip=5A and ton=150µs. The improvement when RBD palm oil is used as dielectric is 48.88% compared to kerosene. With the increase in peak current, the EWR increases but it is inversely proportional to the pulse duration. The lowest EWR is obtained at the same IP=1A and ton=150µs for both RBD palm oil and kerosene which is 0.0010mm3/min and 0.0002mm3/min respectively. The minimum value of Ra for RBD palm oil is 2.15µm at IP=1A and ton=150µs, while for kerosene it is 2.11µm at IP=1A and ton=150µs. In terms of finishing process efficiency, RBD palm oil, a biodegradable oil-based dielectric fluid, has shown significant potential in EDM processing of AISI D2 steel

Synthesis and characterization of magnesium doped calcium phosphatefor bone implant application

Calcium phosphate (CaP) has been extensively studied for its excellent performance in promoting bone tissues ingrowth or osseointegration as in bone graft substitute and biomimetic coating of prosthetic implants. However poor mechanical properties of CaP has made its limited in a load bearing application and it has become an interests in research investigation for biomedical applications challenging. Here we employ an optimized mechanochemical method to synthesis calcium phosphate and Magnesium-doped Calcium Phosphate (Mg-CaP) in various weight percentages. The change of adsorption band in FTIR indicates that the Mg has been substituted into CaP. Doping by MgOH is found to effectively increase the densification and hardness of CaP when sintered at 1200 oC. Mg doping could be contributes to the improvement in artificial implant of calcium phosphate (CaP) for bone implant application in load bearing area