Prediction of Cutting Force in End Milling of Inconel 718

Inconel is prominently known as a hard material to be machined. Due to stability during extreme temperature, it is widely used in aerospace components especially turbine blade (Kitagawa et al. , 1997, Ulutan and Ozel, 2011). Some processes require ball end type due to intricate and complex shape. This curve cutting tip tool reduces stress concentration. However, the complex shape of round nose geometry exhibit tool wear mode that different than flat end milling tool (Aspinwall et al. , 2007). Studies from previous researchers found that the interrupted cutting process causes flaking especially during machining high tensile strength (Figure 1) (Kasim et al. , 2013). This paper presents the effect of cutting speed, feed rate, and depth of cut on the cutting force when machining Inconel 718 under minimum quantity lubrication. The response surface methodology (RSM) was used in the experiment, and a Box–Behnken design was used to determine the cause and effect of the relationship between the four cutting parameters and cutting force. The investigation milling parameters were cutting speed (100, 120, and 140 m/min), feed rate (0.1, 0.15, and 0.2 mm/tooth), axial depth of cut (0.5, 0.75, and 1.0 mm) and radial depth of cut (0.2, 1, and 1.8 mm). The result shows that the radial depth of cut was the dominating factor controlling cutting force, it was followed by axial depth of cut and feed rate. The relationship between cutting force of various factors was expressed in a three-dimensional response graph (Figure 2). The second order prediction cutting force equation (1) was developed with a 95% confidence level. The optimum condition required for minimum cutting force include cutting speed of 110 m/min, feed rate of 0.1 mm/rev, axial depth of cut of 0.5 mm, and radial depth of cut of 0.25 mm. The error between the predictive model and the actual of cutting force was less than 3%. With this optimum condition, a cutting force of 144N was obtained

Study on Machinability of Laser Sintered Materials Fabricated By Layered Manufacturing System: Influence of Different Hardness of Sintered Materials

This paper investigates machinability of laser sintered materials fabricated by layered manufacturing system. Different types of sintered materials; chromium molybdenum (SCM) sintered material and maraging steel (MAS) sintered material were fabricated by using selective laser melting (SLM) method. Measurement of cutting force and cutting temperature were carried out by using ball end mill in order to understand the influence of different hardness of sintered materials on machinability. Bulk carbon steel (JIS S55C) was selected as reference steel. Experimental results show that MAS sintered material is difficult to machine material where cutting force of MAS sintered material was higher than SCM sintered material. However, even though MAS sintered material has higher hardness than SCM sintered material, cutting temperature was low due to high thermal conductivity. From these results, MAS sintered material can be considered as good material to produce mold due to its high hardness and good machinability

Helical Micro-Hole Drilling Of Chemically Strengthened Glass Using Capsule-Shaped Electroplated Diamond Tool

This study investigates the micro-hole drilling performance of chemically strengthened glass plate by using a capsule-shaped electroplated diamond tool and the helical drilling method. Three different helical pitch conditions were tested to drill holes with a diameter of 1 mm. The number of drilled holes, grinding force, and maximum crack size were measured along with the observation of the drilled holes to evaluate the performance of the micro-hole drilling. From the experimental results, it was found that as the size of helical pitch decreased, the number of drilled holes increases where the average grinding force generated becomes smaller. By using small helical pitch condition, 43 holes could be drilled but the maximum crack size generated at the outlet side of the drilled hole is not able to achieve the high-grade quality compared to the inlet side. The resultant grinding force generated when the tool tip nearing the outlet side of the glass plate has caused the large crack at a certain position on the outlet side

Study on reduction of residual stress induced during rapid tooling process: Influence of heating conditions on residual stress

金沢大学理工研究域機械工学系This paper deals with the reduction of residual stress induced during the selective laser melting with a mixture of ferrous based metal powder. To evaluate the residual stresses induced during layered manufacturing processes, a strain gauge is attached on the bottom face of the base plate. The residual stress within the consolidated structure is calculated from the amount of strain change measured by the strain gauge when the consolidated structure is cut with an end mill. The influences of base plate thickness and consolidated structure height on the residual stresses are investigated. In addition, the effect of pre-heating and post heating by a laser beam irradiation are evaluated. The results showed that the deformation of the base plate increased with the increase of the consolidated layer and the decrease of base plate thickness, and the deformation was flattened when the consolidated structure was completely removed with the end mill. The deformation was related to the induced residual stresses. The residual stress distribution within the consolidated structure in the z direction was extremely large at the top layer of the structure and the boundary between the base plate and consolidated structure. The residual stress at the first layer of the structure decreased when the base plate was heated before consolidating the deposited powder. The residual stresses decreased when each of the consolidated layers was repeatedly heated by the laser beam irradiation. © (2010) Trans Tech Publications

Thermal conductivity of metal powder and consolidated material fabricated via selective laser melting

Selective Laser Melting (SLM) is a direct fabrication of part through layer by layer powder deposition and successive laser beam irradiation based on Computer Aided Design (CAD) data. One of the important properties in SLM is thermal conductivity of metal powder. This is because the ability of metal powder to conduct heat will affect the consolidation process during SLM. In this paper, thermal conductivity of metal powders with different particle diameters and their mixture was analysed. Other than that, thermal conductivity of consolidated materials fabricated via SLM process was also studied. In order to measure the thermal conductivity of metal powder, a theoretically verified method which was previously developed by the authors was used. Determination of thermal conductivity of consolidated material was analysed using laser flash technique. It was found that the thermal conductivity of powder metal was influenced by bulk density and particle diameter of metal powder. In this study also, metal powders of different particle diameters were mixed with various volume ratios, and its effect was discussed. Thermal conductivity of the consolidated materials was also examined, and its relation to porosity was elaborated. © (2012) Trans Tech Publications, Switzerland

Electroless Ni-Co-Cu-P Alloy Deposition in Alkaline Hypophosphite Based Bath

The use of electroless deposition method to deposit nickel alloy attracts attention due to its uniformity, corrosion resistance in neutral media and low friction. Quaternary nickel alloy deposit can be achieved by adding metal ion additive into the plating bath. Furthermore, the use of alkaline bath can accelerate the deposition rate, and provide sufficient thickness for corrosion protection. In this study, an electroless quaternary nickel alloy is deposited on iron coupons by adding cobalt and copper ions in hypophosphite based Ni-P alkaline bath. The nickel alloy deposit surface morphology is studied using scanning electron microscope (SEM) and x-ray fluorescence(XRF). Corrosion behavior of the nickel alloy is investigated using polarization curve measurement in 3.5wt% NaCl aqueous solution. From the results, the elecroless Ni-Co-Cu-P alloy coating produced at higher plating bah pH is harder than the lower bath pH. Higher Co, Cu and P content in the Ni alloy exhibit broader passive area in the polarization curve measurement results

WARPAGE ANALYSIS VERIFICATION BETWEEN SIMULATION AND EXPERIMENTAL OF DUMBBELL PLASTIC PART IN THE INJECTION MOULDING PROCESS

Injection moulding is widely used to produce a variety of plastic parts. Its process involved various process parameters, which plays an important roles in influencing the quality and productivity of plastic parts. In this case, the application of Computer Aided Engineering (CAE) software is essential to enhance the quality of plastic parts in the injection moulding industry. This paper deals with the application of Moldflow Plastic Insight (MPI) intergrated with a statistical technique using Taguchi Method. The purpose of this application is to study the effect of process parameters on warpage deflection in dumbbell plastic part. Subsequently, the result of CAE simulation was validated with the aid of experimental data result. The Process parameters involved in this study were core temperature, cavity temperature, melt temperature and cooling time. Based on the simulation and experimental results, it was found that the most significant parameter affected warpage deflection is cavity temperature, followed by core temperature, melt temperature and cooling time. In addition, the results show that the minimum and maximum percentages of the differential of warpage deflection between the simulation and experiment are 4% and 10.89% respectively. Thus, this indicates that there is a good agreement between the simulation and the experimental data result

Study on thermal and strain behaviour in selective laser sintering process

This paper investigates thermal and strain behaviour in the selective laser sintering process with a mixture of SCM, Cu and Ni metal powder. In-process monitoring of strain change and temperature at the base plate is proposed in order to investigate thermal and strain behaviour induced by selective laser sintering. A strain gauge was attached to the bottom surface of the base plate while a thermocouple was inserted at a distance of 2 mm from the top surface of the base plate. Changes in the strain and the base plate temperature were observed using an oscilloscope during the laser sintering process. The results showed that the development of strain within the sintered structure was affected by the processing temperature. Besides that, after the laser sintering process was completed, the strain value increased gradually and became constant as it reached room temperature. This strain value was found to correspond with the test model\u27s deformation. In addition, the effects of laser scanning direction and laser energy density during the process were observed. Measurement of the test model\u27s deformation was also carried out to discover its relationships to strain change and processing temperature. The results showed that the sintered structure produced by laser scanning of a sector along the width induced less residual strain, which resulted in less deformation. In contrast, both residual strain and deformation were found to be higher when the laser scanning was carried out along the length. Furthermore, when a low laser energy density was used, less deformation of the sintered structure could also be obtained. © (2012) Trans Tech Publications

Interchangeable Core And Cavity Plates For Two-Plate Family Injection Mould

This study modified a two-plate family plastic injection mould to become interchangeable by changing the core and cavity plates using an existing mould base. The plastic parts produced in the modified two-plate family plastic injection mould included tensile, hardness, impact and flexural test specimens. The cavities of the plastic parts were machined at the parting surface of core plate. Meanwhile, the feeding systems including runner and gate system were machined at the cavity plate to ensure molten plastic can be injected in the cavity area. Various factors have been considered during the designing and fabricating process. This is to ensure the process of assembly between mould plate and standard mould parts can be done perfectly. The plastic parts in the family mould were successfully injected after mould was completed assembled and mould trial was performed. The plastic parts which had been ejected from the family injection mould are purposely produced for future research to study the mechanical properties of plastic materials