Abstract: This study presents the results of experimental studies carried out to conduct a comprehensive investigation on the influence of Electrical Discharge Machining (EDM) input parameters on characteristics of EDM process. The machining parameters include peak current, servo voltage, pulse ON time and pulse OFF time. The study was conducted using 2 levels of Full Factorial Method in Design of Experiments. The design expert software employed to perform all the data analysis for Full Factorial and Central Composite Design (CCD) experiments. This study evaluates the machining performance of the Stainless Steel 316L using Sodick EDM linear motor series AM3L which employed Copper impregnated graphite diameter 7.0 mm as the tool electrode. The response variables are material removal rate (MRR), electrode wear rate (EWR), surface roughness (SR) and dimensional accuracy. The result shows that the peak current was the most significant factors to all variable responses. The servo voltage does not have significant effects to the machining responses in RSM. Higher current produced higher MRR, EWR, SR and Dimensional Accuracy. Maximum MRR was obtained at peak current range from 27amp to 38amp, pulse on time range from 120μs to 145μs and 60μs of pulse off time. Maximum EWR was obtained at peak current range from 27amp to 37amp, pulse on time range from 140μs to 160μs and 60μs of pulse off time. High probably, the minimum EWR only can be obtained if peak current parameter sets greater than 45amp. Lower dimensional accuracy and SR obtain at 5amp of pulse on time. Higher pulse off time produced lower MRR and EWR.Keywords: EDM Die sinking, Stainless Steel 316L, Copper Impregnated Graphite Electrode, Response Surface Methodology, Surface Roughness, Material Removal Rate, Electrode Wear Rate, Dimensional Accuracy
Abstract: In micro scale, the size of cutting tool and shape significantly contributed to the machining performance. Many studies have been done to improve the cutting tool life and machined surface quality. Problems could become more severe when the workpiece has a low thermal conductivity while having high level of ductility such as titanium alloy. In this study, micro ball mill cutting tool is selected to produce a linear groove on a titanium alloy plate. The process is integrated with a laser source as a pre-heating element on the work piece surface. The condition of the flank surface of the tools and cutting force were observed and discussed. The influence of tool orientation and laser heating parameters in laser assisted micro ball milling (LAMM) were also discussed. It was found out that adhesion is the dominant tool wear mechanism thus fluctuate the cutting force value.
Abstract: Nowadays, carbon fiber reinforced plastics (CFRP) composites is widely used in the aerospace industry due to its excellent mechanical properties. In laser cutting process, high powers are used to cut materials then material melts and burns leaving edges with a high quality finish. To fulfill the high demand of cutting quality, a set of laser cutting parameters of CFRP material are studied. The objective of this experiment is to obtain an optimum laser cutting parameter thus minimizing the cutting defects particularly on kerf width at the top and bottom surfaces. The analysis of process parameter was carried out using DOE, Design Expert 6.0.8. Cutting speed, pulse duration, pulse repetition rate and pulse energy were analyzed at two levels. By the optimizing the parameter setting, significant improvement in cutting quality has been achieved.
Abstract: Advancing of micro-milling process via ultrasonic vibration assist has been proven able to improve machining characteristics such as surface roughness quality and dimension accuracy. The improvement is due to the cutting motion of Vibration Assisted Machining (VAM) process. Thus, for every vibration motion manner, the cutting characteristic of the VAM system will be difference from one to another. This paper presents the development approach of ultrasonic vibration assisted micro-milling (UVAM) using tilted 45° XY stage. It covers theoretical perspective and the influence of Minimum Quantity Lubrication (MQL) system as cutting fluid. It will emphasize on the theory of surface roughness, dimension tolerance and cutting tool life. Piezo-actuator is used as fast servo vibration mechanism in specific axis input with controlled signal. The input signal is sine wave with controllable frequency and amplitude to allow mechanism control algorithms to be develop during the process. In addition, the effect of cutting fluid was be analyzed to understand the potential capabilities of this aid on UVAM process.
Abstract: This study discussed about the influence of the cutting speed and radial depth of cut on surface integrity (microhardness and work-hardening) when performing hard milling of AISI D2 workpiece. By using PVD-TiAlN, nine experimental trials were performed at various cutting speeds of 80, 100 and 120 m/min and various radial depth of cut of 3, 4 and 5 mm as feed and depth of cut remain constant at 0.05 mm/tooth and 0.05 mm. From the result, due to high cutting temperature generated, the cutting speed adversely affects the microhardness value of the subsurface layer. At higher cutting speed of 120 m/min higher hardness values were obtained when compared with lower cutting speed of 80 m/min. As for the effect of the radial depth of cut it is clear that it influences the microhardness beneath the surface. Higher microhardness recorded from the radial depth of cut increment associated with high cutting temperature generated during machining.
Abstract: Metal casting is a process of metallurgical forming by liquidize of material up to certain high temperature to achieve perfect chemical reaction and high level quality products. Auto pour means pouring the metal liquid into the mould not by manual operation but more than automatically done by a set of machine without any human intervention. This paper aims to describe the process of automation for brake drums where several parameters are compare with manual process. The standard time, cycle time, rejection rate, dimension, chemical composition and product quality have been analyzed. The results shows that the standard time reduce to 40%, rejection rate less 5%, tensile strength 3% higher because of better pouring process. The other parameters are the same for both manual or automatic pouring process. The conclusion of this research is that the auto pour provides better results in term of productivity and quality.
Abstract: Micro milling of super alloy materials such as nickel based alloys is challenging due to the excellent of its mechanical properties. Therefore, new techniques have been suggested to enhance the machinability of nickel based alloys by pre-heating the workpiece’s surface to reduce its strength. Determining the processing parameters and their effects to the processing characteristics are crucially important. However, not only the micro-milling parameters need to be considered, but the pre-heating parameters are also need to take into consideration as well. These parameters are expected to improve the machinability. In this study, the experiment of LAMM in Inconel 718 was conducted with considering laser power, cutting speed, depth of cut, feed rate and laser-to-cutting tool distance. From the result, the effectiveness of laser assisted and cutting parameter in term of cutting force and tool wear was identified by comparing between conventional and LAMM. Finally, the optimum range of machining parameters can be determined.
Abstract: This paper presents the melt flow behavior (MFB) of an acrylonitrile butadiene styrene (ABS), Polyproplene (PP), Polylactic Acid (PLA), ABS mix 10% Copper and ABS mix 10% Iron in the simulation. In this study, the effect MFB of ABS mix with 10% Iron and 10% Copper material was investigated based on the viscosity, density, thermal conductivity, melting temperature and specific heat of material properties. The MFB of metal filled in polymer matrix composite (PMC) through the FDM nozzle was investigated using Finite-Element Analysis (ANSYS CFX 12). Based on the result obtained, pressure outlet of mix ABS copper and ABS iron in extruder nozzle was higher value compared with others plastic material. The velocity was increased since the nozzle diameter is smaller than the entrance diameter. It can be observed that, the melt flow behavior of metal filled in PMC are affected on pressure drop, velocity and the nozzle size at the exit nozzle.
Abstract: This paper presents the melt flow behavior (MFB) of an acrylonitrile butadiene styrene (ABS), High Density Polyethlene (HDPE), Polyproplene (PP) and a combination of ABS-Iron in the extrusion process. In this study, the effect MFB of variety's polymers and ABS mix with 10% Iron material was investigated based on the viscosity, density, thermal conductivity, melting temperature and specific heat material properties. The MFB of FDM system was investigated using Finite-Element Analysis (FEA) by ANSYS CFX 12. Based on the result obtained, it was found that, the material velocity increase when the nozzle diameter is smaller than the entrance diameter. The higher temperature distribution along the MFB of ABS mix with 10% Iron is 43.15 K compared with original ABS, which is 539.15K.
Abstract: Design and fabrication of an object with parts embedded internally within the part has always been a difficult challenge to fabricate. This is mainly due to limitations in design for manufacturing (DFM). The objective of this work is to investigate improvements in overcoming limitations in DFM of non-metallic object with embedded part within a part through 3D printing technology and silicone rubber. 3D printing technology is a type of Rapid Prototyping (RP) method which has limitations in its material durability and product failure rate. This technology combined with silicone rubber is envisaged capable to overcome some of the limitations in DFM while increasing its durability. Layer manufacturing using 3D printing is used to construct scaffolding of the end product and silicone rubber used as material to fill the cavities. The end product is a unique “one-piece” outdoor water-feature cage that has no assembly of parts between its various internal and external components which entraps a free rotating ball feature inside the cage. Both limitations in DFM of a part within a part and improving prototype materials durability had been overcome.