Pengaruh Variasi Kecepatan Dan Kuat Arus Terhadap Kekerasan, Tegangan Tarik, Struktur Mikro Baja Karbon Rendah Dengan Elektroda E6013

Low carbon steel can be welded with all kinds of electric welding using shielded metal arc welding (SMAW), therefore it is compulsory that the design and method of welding should match to the behavior of welding, the material properties to be welded, utilizing of the construction and surrounded circumstances. In this research the influence of welding speed and current on hardness, ultimate strength and micro structure of materials will be investigated. The results show that the highest value of average VHN (Vickers Hardness Number) of specimens occurred at currents 80A with a speed of 0.35cm/sec and currents100A with a speed of 0.37cm/sec. While in the tensile test, the highest ultimate strength was resulted at currents 80A and a speed of 0.15cm/sec. In captured microstructure on HAZ region (Heat Affected Zone), can be seen the irregular elements in the area HAZ ferrite and perlite Based on these results, it can be concluded that, hardness value tend to be higher if low current and higher welding speed used

Effects of metal fillers on properties of epoxy for rapid tooling inserts

Metal filled epoxy has been recognised as an alternative material used in rapid tooling application such as core and cavity for injection moulding. The addition of fillers into the metal filled epoxy has proven to increase the epoxy's mechanical performance such as wear, strength, improved machinability and thermal properties. Physical and thermal properties such as density, thermal diffusivity, thermal conductivity and compressive strength were analysed to evaluate the effects of inclusion of metal fillers such as copper and brass particles into the blended epoxy matrix. Brass and copper powders were added separately ranging from 10%, 20% and 30% of its weight into the aluminium filled epoxy mix ratio. Increased density, thermal diffusivity, and thermal conductivity values were evident with a linear trend when both filler compositions were increased from 10% to 30%. Brass and copper density values of 2.22 g/cm3 and 2.08 g/cm3 respectively were recorded at the highest filler composition. Copper fillers with 30% composition in epoxy matrix exhibited the highest average value of thermal diffusivity of 1.12 mm2/s and thermal conductivity of 1.87 W/mK, while the inclusion of brass showed no significant improvement in the properties. Compressive strength increased from 76.8 MPa to 93.2 MPa with 20% of brass fillers and 80.8 MPa with 10% of copper fillers composition. The addition of more metal fillers resulted in a decrease in compressive strength due to the presence of porosity. This study validated previous researchers that fillers enhance mechanical, thermal properties and density of aluminium filled epoxy

Application of RSM and ANN in predicting surface roughness for side milling process under environmentally friendly cutting fluid

The paper presents a potential study on prediction of surface roughness in side milling by optimization techniques approaches. Two methods, response surface methodology (RSM) and artificial neural networks (ANN) were used for optimized prediction. The model of surface roughness was expressed as the main parameter in side milling term of cutting speed, feed rate and axial depth of cut. Rotatable central composite design (RCCD) is employed in developing second-order response surface mathematical model. The ANN model using a multi-layer feed forward, back propagation and training function Levenberg-Marquardt (LM) algorithm with a single hidden layer. Vegetable oils have often been recommended as sustainable alternative cutting fluid since the ecological and health impacts in the use of mineral oil have been questioned and also the rising cost of mineral oil. The advantages of oxidative stability of coconut oil as vegetable oil were utilized in this study to investigate surface roughness of low carbon steel. The machining of ferrous alloy like steel is sometimes a difficult task. This study used uncoated tool because it is suitable when turning and milling alloy. Flood condition was selected because it has been proved effective at low cutting speed. The analysis predicted by RSM and ANN models resulted a good agreement between the experimental and predicted values. The results indicated that the ANN model predict with more accurate compared with the RSM model

Machinability analysis of drilled bamboo fibre reinforced polymer (BFRP) composite

In globally the technology keep improving continuously from time to time especially in materials development. Many researchers and manufacturer found interested in substituting synthetic with natural materials. By utilizing natural surrounding sources, it will impact on the product improvement and creating environmental awareness. Besides on many available natural fibres for reinforcements, bamboo fibre has been identified as one of reliable reinforcement in polymer matrix. The mechanical properties of bamboo fibre composite at moderate strength compared with another types. However, bamboo is grows naturally in the foothills or can be planted and easily to find in the Peninsular Malaysia. Further machining process on composites such as drilling will affecting strength properties of the composite, this is due to discontinuous of the fibre after drilled. This study will evaluating on influence of machining parameters and tool geometry on residual tensile strength and delamination damage of drilled bamboo fibre reinforced polymer (BFRP) composites. Fabrication of the composite using resin infusion process by vacuum assisted resin transfer moulding. The experiments were developed using Taguchi method and tested according to ASTM D3039 requirement. The results were analysed using analysis of variance (ANOVA). Finally, the optimum condition for maximizing residual tensile strength and minimizing delamination factors on the drilled bamboo fibre reinforced composite are suggested

Optimization of surface roughness using RSM and ann modelling on thin-walled machiningunder biodegradable cutting fluids

Precise milling of thin-walled components is a difficult task process owing to the geometric complexity and low stiffness connected with them. This paper is concerned with a systematic comparative study between predicted and measured surface roughness. RSM and ANN applied in prediction and optimization of milling thin-walled steel components. Cutting speed, feed rate, radial and axial depth of cut are the main affecting process parameters on surface roughness. In order to protect our precious environment, this work utilized vegetable oil as biodegradable cutting fluids that resolve the lowest amount of ecological contamination provide well economic conditions. The milling have done under flood cooling and using uncoated carbide as cutting tool. The results indicate that the RSM and ANN models are very close to the experimental results, ANN predictions show better convergence than the RSM model. The best of surface roughness value (0.314 μm) can be achieved with a desirability of 98.6%, cutting speed, feed rate, radial and axial depth of cut were 125 m/min, 0.04 mm/tooth, 0.25 mm and 10 mm, respectively. The best configuration of the ANN structure was 4-16-1. The feed rate cause most significant effect on surface roughness, followed by axial and radial depth of cut

Experimental vibration study in milling thin-walled Ti6Al4V under MQL using coconut oil as cutting fluid

In thin-walled Titanium Ti6Al4V machining, vibration is the dominant factor affecting the quality of components. Excessive vibrations can generate chatter, this condition occurs because it is not suitable in choosing machining parameters. Chatter is not expected because it causes dimensional errors, rapid tool wear and poor surface finish. This experiment tries to identify chatter-free conditions with the appropriate parameters. Uncoated carbide is used as a cutting tool with a diameter of 10 mm and machining under the MQL system with coconut oil as a cutting fluid. In the result of the milling showed if this machining is free of chatter, where from frequency was achieved is not equal to the natural frequency from simulation, then this is also approved from result surface roughness and surface photography. In surface roughness result, the value is smaller than minimum critical amplitude, where good result in high value of the cutting speed and small feed rate and result of the surface photography was identified no severe surface condition along thin-walled. The experiment also calculated for non-thin-walled Ti6Al4V as evaluation, where the result of both acceleration and surface roughness was obtained smaller than milling thin-walled

A review of minimum quantity lubrication technique with nanofluids application in metal cutting operations

Minimum quantity lubrication (MQL) technique did not only serve as a better alternative to flood cooling during machining but enhance better surface finish, minimizes the cost, reduces the impact loads on the environment and health hazards on the operation personnel. However, the coolant or lubrication media used in MQL technique posed certain restrictions especially at very high cutting speeds where the lubricating oil tends to evaporates as it strikes the already heated cutting tool at elevated temperature. Desire to compensate for the shortcomings of the lubricating media in the MQL technique led to the introduction of nanoparticles in the cutting fluids for use in the MQL lubrication process. Nanoparticles have much higher and stronger temperature-dependent thermal conductivity and enhanced heat transfer coefficient at very low particle concentration, which are key parameters for their enhanced performance in many of the machining applications. Optimizing the nanoparticles concentration leads to efficiency in most of their application. Their ball bearing effect lubrication at the cutting zone through formation of film layer which reduces friction between the contact surfaces thereby reducing cutting force, temperature and tool wear. It has been reported in various studies that nanoparticles introduction in cutting fluids led to excellent machining performance in reduction of cutting forces, reduced tool wear, reduced cutting temperature and improved surface finish of the work piece thereby increasing productivity and reduction of hazards to the health of personnel and the environment better than the pure or conventional MQL process. Thus, the application of various nanoparticles and its performances in metal cutting operations with respect to the cutting forces, surface finish, tool wear and temperature at the cutting zone are evaluated and highlighted

Investigation of tool entry strategy when pocket milling titanium alloy, ti-6al-4v under wet condition

Tool entry strategy determines how the cutting tool enters and moves into the workpiece during pocket milling operation without collision between the tool and workpiece. Optimal selection of tool entry and its parameters settings during pocket milling are crucial in order to improve the tool life and accuracy of the machined part. Pocket milling process is performed purposely to reduce the weight of the parts as it involved high material removal and generally associated with high manufacturing costs. This work aims to investigate the effect of tool entry strategies on the tool wear of TiAlN coated carbide insert when pocket milling titanium alloy, Ti-6Al-4V under wet coolant condition. Two tool entry strategies namely circular and angular ramping were evaluated under rough machining condition. Three main cutting parameters of cutting speed (Vc), feed rate (fz) and depth of cut were used with constant values at 90m/min, 0.1mm/tooth and 2mm respectively using fixed entry angle of 3°. Tool wear was observed and recorded for both circular and angular ramping entry modes at the end of the experiment. Experimental results showed that tool flank wear increases as the number of pass or run increases. During the first run, the recorded flank wear was at 0.016mm and 0.033mm for circular and angular entries respectively. At the fifth or the last run, the recorded flank wear was 0.028mm and 0.041mm for circular and angular entries respectively. It can be clearly concluded that the best tool entry when pocket milling Ti-6Al-4V was circular ramping as compared to angular entry due to the small immersion angle and intermittent tool engagement. These phenomena made it possible to ensure better stability during machining and prolong the tool life thus reducing the machining cost and enhance the overall performance of the pocket milling process

Cutting force prediction when green machining of thin-walled ti-6al-4v under dry and mql-cutting using response surface methodology and artificial neural networks-algorithm

Thin-walled parts most frequently used to decrease the weight of different design part of the aviation industry. Ti6Al4V is highly applied in thin-walled because it possesses several promising inherent characteristics like high strength maintained at elevated temperature, low density, high creep etc. Nevertheless, the machinability of titanium alloys is discussed to be poor. The cutting of these materials is difficult owing to the brittle nature and the high chemical affinity to cutting tools. The cutting temperature between tool and chip with easy reaches beyond 1000°C. Cutting force will enhance as a result of high cutting temperature. Consequently, the investigation of the cutting force is necessary, which spindle speed, feed rate and depth of cut were usually chosen as cutting parameters. In order to meet the increasing requests for cleaner manufacturing of titanium alloys, it wiser to apply vegetable oil as cutting fluids wherever it is biodegradable at all stages of its life. Coconut oil was utilized in this work owing to its oxidative stability higher than that of other vegetable oils in machining industries. However, the costs of vegetable cutting fluids are still high enough, and the cost associated with titanium machining is also high due to lower cutting velocities. Therefore, the dry cutting process and minimum quantity lubrication (MQL) were considered to decrease the cost of related to fluid and energy consumption significantly. In this paper, MQL cutting using coconut oil and dry cutting are associated with studying cutting force during milling thin-walled Ti6Al4V with uncoated carbide tools. The result of this investigation showed that the cutting force is lower when MQL was applied than the dry cutting condition. The analysis through ANN indicated better prediction with the experiment rather than RSM