Mohd Hamdi Abd Shukor

Experimental Study on Minimizing Edge Chipping in Glass Milling Operation Using an Internal CBN Grinding Tool

Glass is one of the most difficult materials to be machined due to its brittle nature and unique structure as frequent occurrence of fracture and edge chipping during machining has to be avoided. To minimize edge chipping of the machined glass, which is common when cutting materials harder than 50 HRC, adopting right parameters is required followed by additional effort and cost. This article presents experimentation in minimizing the edge chipping for glass milling operations using an internal cubic boron nitride grinding tool by optimizing the machining parameters. Taguchi optimization method is the most effective method to optimize the machining parameters, in which the most significant response variables affecting edge chipping could be identified. In glass milling operation, several machining parameters are considered to be significant in affecting edge chipping. These parameters include lubrication pressure and direction, feed rate, spindle speed, and depth of cut. The standard orthogonal array of L 16 (44) is used, while the signal-to-noise response analysis and analysis of variance methods are carried out to determine which parameters are statistically significant. Finally, confirmation tests are carried out to investigate the optimization improvements.

Optimizing the Machining Parameters in Glass Grinding Operation on the CNC Milling Machine for Best Surface Roughness

Glass is one of the most difficult materials to be machined due to its brittle nature and unique structure such that the fracture is often occurred during machining and the surface finish produced is often poor. CNC milling machine is possible to be used with several parameters making the machining process on the glass special compared to other machining process. However, the application of grinding process on the CNC milling machine would be an ideal solution in generating special products with good surface roughness. This paper studies how to optimize the different machining parameters in glass grinding operation on CNC machine seeking for best surface roughness. These parameters include the spindle speed, feed rate, depth of cut, lubrication mode, tool type, tool diameter and tool wear. To optimize these machining parameters in which the most significant parameters affecting the surface roughness can be identified, Taguchi optimization method is used with the orthogonal array of L8(26). However, to obtain the most optimum parameters for best surface roughness, the signal to noise (S/N) response analysis and Pareto analysis of variance (ANOVA) methods are implemented. Finally, the confirmation test is carried out to investigate the improvement of the optimization. The results showed an improvement of 8.91 % in the measured surface roughness.

Novel uses of SiO2 nanolubrication in end milling of medium carbon steel for higher compressive residual stress measured by high-energy X-ray diffraction data

Milling is a machining process that removes any desired material from the surface by using relative motion between a work piece and a rotating cutter where the cutting tool intermittently enters and leaves the work piece. The milling process operates in two modes, namely, conventional (up) mode and climb (down) mode. Both modes are known for their significant effects on surface integrity due to the entering movement of the cutting tool and the formation of the chips during cutting process. Use of flood lubrication can improve the residual stress and surface quality of the component. It controls the temperature in cutting zone, reduces the power required, washes away chips, and reduces friction between chips, tools, and workpieces. Moreover, it has a great effect on the environment too. Minimum quantity lubrication can be used as an alternative of lubrication for clean machining. With an addition of nanoparticles into the minimum quantity lubrication, it is expected to enhance the machining performance that meets the environmental friendly purposes. Residual stresses remain in a solid material in the absence of external loading or thermal gradients, which is sometimes undesirable. The presence of compressive residual stresses is beneficial, while the presence of tensile stresses is detrimental. In order to study the residual stress and its relation with the surface quality (after milling process), the effects of reduced oil consumption in minimum quantity lubrication and the addition of SiO2 nanoparticles in minimum quantity lubrication for clean machining are presented in this research. Results indicate that there is an improvement in residual stresses and surface quality especially during conventional (up) milling under minimum quantity lubrication and minimum quantity lubrication–SiO2 nanolubrication condition.

Interfacial Reaction Analysis of Cu-Sn-Ni-P/Cu Joint Using Microwave Hybrid Heating

Microwave hybrid heating (MHH) technique was used to investigate the formation of intermetallic compound layer at Cu-7.0Ni-9.3Sn-6.3P/Cu interface. Two different susceptor materials; graphite and silicon carbide were used to provide initial heating of the filler alloy before it starts couple with the microwaves and melted on the Cu surface. The interface of IMC layer was characterized using Scanning Electron Microscope (SEM), energy dispersive X-ray spectrometry (EDS) and microhardness. Metallurgical study showed the formation of the IMC layer with multiphase at the joint interface for microwave heating of both susceptor materials. The thickness of IMC layer heating in silicon carbide susceptor was three times thinner than heating in graphite susceptor; 16.5 μm and 50.5 μm, respectively. The findings showed that microwave hybrid heating can be used to join Cu-7.0Ni-9.3Sn-6.3P/Cu and controlled the thickness of IMC layer.

Investigate the Lubrication Effects on Cutting Force and Power Consumption in Up and Down End Milling

Milling is a machining process by which a surface is generated by a progressive chip removal. An experimental investigation has been carried out on the performance of up and down milling under dry and flood conditions when end milling medium carbon steel utilizing titanium coated carbide tools. The performances are evaluated in terms of the cutting force, specific energy and power of cutting tool. The results show that milling in dry condition under up milling mode produce higher cutting force, specific energy and power. However, cutting under down milling mode gives less significant effect either being cut in dry or flood condition.

Enhancement of as-sputtered silver-tantalum oxide thin film coating on biomaterial stainless steel by surface thermal treatment

Stainless steel 316L (SS316L) is extensively used as surgical/clinical tools due to its low carbon content and excellent mechanical characteristic. The fabrication of metal ceramic based on this metallic biomaterial favor its biofunctionality properties. However, instability phase of amorphous thin film lead to degradation, corrosion and oxidation. Thus, thin film coating requires elevated adhesion strength and higher surface hardness to meet clinical tools criteria. In this study, the SS316L was deposited with micron thickness of Ag-TaO thin film by using magnetron sputtering. The microstructure, elemental analysis and phase identification of Ag-TaO thin film were characterized by using FESEM, EDX and XRD, respectively; whereas the micro scratch test and micro hardness test were performed by using Micro Scratch Testing System and Vickers Micro Hardness Tester, respectively. It was found that the coating thin film’s adhesion and hardness strength were improved from 672 to 2749 mN and 142 to 158 Hv respectively. It was found that the as-deposited surface were treated at 500 °C of temperatures with 2 °C/min ramping rate enhance 4.1 times of the adhesion strength value. Furthermore, FESEM characterization revealed coarsening structure of the thin film coating which can provide high durability service.Stainless steel 316L (SS316L) is extensively used as surgical/clinical tools due to its low carbon content and excellent mechanical characteristic. The fabrication of metal ceramic based on this metallic biomaterial favor its biofunctionality properties. However, instability phase of amorphous thin film lead to degradation, corrosion and oxidation. Thus, thin film coating requires elevated adhesion strength and higher surface hardness to meet clinical tools criteria. In this study, the SS316L was deposited with micron thickness of Ag-TaO thin film by using magnetron sputtering. The microstructure, elemental analysis and phase identification of Ag-TaO thin film were characterized by using FESEM, EDX and XRD, respectively; whereas the micro scratch test and micro hardness test were performed by using Micro Scratch Testing System and Vickers Micro Hardness Tester, respectively. It was found that the coating thin film’s adhesion and hardness strength were improved from 672 to 2749 mN and 142 to 158 Hv respect...

Effect of Isothermal Aging on Mechanical Properties of Sn-3.0Ag-0.5Cu Solder Alloy with Porous Cu Interlayer Addition

The performance of Pb-free SAC305 solder joint added with porous Cu interlayer was investigated. The porous Cu interlayer was placed in a sandwich-like layer between SAC305 solder alloy and rod Cu as the substrate metal. Two different pores, 15 ppi (pore per inch, P15) and 25 ppi (P25) with the pore size approximately ϕ1.7 and ϕ1.0 mm, respectively were used. The soldering process of solder joint was carried out in three different soldering temperatures of 267, 287 and 307 °C while the holding time was set at 300 s. Tensile test was performed to evaluate the joining strength of the solder alloy with loading rate of 0.5 mm/min. The highest joint strength was recorded at 53 MPa when soldered with P25 porous Cu interlayer at 307 °C. High thermal aging test was performed in an oven, heated to temperature of 150 °C for aging time of 100, 200 and 500 h to investigate the heat and time effect on the joint strength. The results indicate the reduction of strength at the aged sample with the increased aging time. The crack initiates dominantly at the interfaces between the porous Cu/SAC305. In general, solder joint soldered with P25 of porous Cu joints have greater tensile strength (23 MPa) than P15 of porous Cu interlayer after aging test.

Addition of porous Cu interlayer to Sn-3.0Ag-0.5Cu lead-free solder joint for high temperature application

The microstructural and mechanical properties of Sn-3.0Ag-0.5Cu lead-free solders added with a porous Cu interlayer were investigated. Two types of porous Cu, P15 and P25 with the diameter of φ1.7 mm and φ1.0mm respectively were used in this study. The porous Cu was arranged in a sandwich-liked layer in between Sn-3.0Ag-0.5Cu solder alloys with rod Cu as a substrate metal. Solder joint without porous Cu interlayer were also prepared as the control sample. Three soldering temperatures of 267°C, 287°C and 307°C with soldering time of 5 minute were applied. Tensile test was performed to evaluate the joint strength of the solder alloy. The result shows that the joint strength increased proportionately with increasing soldering temperature and smaller pore size of porous Cu. Microstructure and fracture surface were observed by using optical microscopy (OM) in order to understand the failure behavior of the joint. It is found that penetration of molten solder alloy into the various pore sizes of porous Cu interlayer significantly influenced fracture morphology and strength of the joint.

Investigation on Spot Welding Effect on Truss Core Panel for Crashworthiness

One of the main concerns of the automotive industry is reduction in structural weight of automobiles. Reduction of weight on vehicles has been proven to lower the usage of fuel, and therefore save a lot of energy in order to move from one place to another. At the same time, reduction of weight often means reduction in material usage, often regarded to be threatening structural strength of parts, components or vehicles body in white (BIW). Truss Core Panel, which has been developed from the study of origami engineering, specifically plane-tilings and space fillings, is a suitable candidate because it can be produced from thin sheet metals and can be joined using spot welding. In this paper, method for evaluating truss core panels for crashworthiness has been established based previous research on crashworthiness evaluation on thin shells. The effect of different configuration of spot welding has been investigated. The number of spot weld (n) along central member and side members of truss core panel has been varied and modeled from n = 2, 4, 6 ... to n = 30, and compared to a truss core panel model that is fully welded along central member and side members. The results also show that it is possible to attain similar mean crush force to fully welded structure with smaller number of spot welds.

Surface Quality Improvement in CNC End Milling of Aluminum Alloy Using Nanolubrication System

Aerospace applications and energy saving strategies in general raised the interest and study in the field of lightweight materials, especially on aluminum alloys. Aluminum Al2017-T4 and Al6061-T6 alloy which are used in this research work have low specific weight and high strength.The (CNC) milling machine facilities provides a wide variety of parameters setup, making the machining process of the aluminum alloy excellent in manufacturing complicated special products. However, the demand for high quality focuses attention especially on the roughness of the machined surface. The key solution for this issue is by introducing the nanolubrication system since it could produce much less friction in the tool-chip interface. In this research work, the Al2017-T4 and Al6061-T6 is machined by using the carbon onion nanoparticle and \(\mathrm{{SiO}}_{2}\) nanoparticles, respecticely when it mixed with ordinary mineral oil at various concentrations as a nanolubrication system. The reduction of surface roughness could be obtained when carbon onion and \(\mathrm{{SiO}}_{2}\) nanolubricant are used compared with the case of using ordinary lubricant due to the tribological properties of the carbon onion and \(\mathrm{{SiO}}_{2}\) nanolubricant to reduce the coefficient of friction in the tool-chip interface.