Papers by Keyword: High Speed Drilling

Abstract: This paper presents a research on experimental and response surface methodology (RSM) approach in evaluating the damage factor of the drilled holes in high speed drilling of glass fiber reinforced polymer (GFRP). From the experiment, the influences of drilling parameters toward damage factor are more prominent in thicker GFRP; where high speed drilling using high speed steel twist drill bit produces lower damage factor in thicker GFRP. Lastly an optimized set of drilling parameters was generated for the use of high speed steel twist drill bit in high speed drilling.

Abstract: Electro discharge machining (EDM) is a process that uses an electric sparks to generate the high temperature and melt the workpiece. One of the EDM process is drilling. In EDM drilling, an electro thermal mechanism is introduced between the electrode and work piece to create the hole. The hole size is dependent on the diameters of electrode used during the drilling process. The present study performs Taguchi method to investigate the optimal process parameters for high-speed EDM super drill machine that is used to make a small hole. The workpiece used is made from titanium alloy (Ti-6: ASTM B348 Grade 5) and the copper electrode is 2.0 mm in diameter. In this experiment, the process parameters that were selected to be optimised are: current pulse off, maximum current and standard voltage levels. An orthogonal array L₉ were employed to analyze the hole enlargement and material removal rate (MRR) depending on 2.0 mm diameter hole penetration. The optimum EDM parameters for hole making process was established and verified with the acquired results.

Abstract: Electro discharge machining (EDM) is a process that use an electric sparks to generate the high temperature and melts the work piece. One of the processes using this method is drilling process. By using this concept, an electro thermal mechanism between electrode and work piece can creates the hole enlargement and the size of the hole its depend on the diameters of electrode are used. The present study performs Taguchi method to investigate the optimal process parameters for high speed super drill machine that was used to make a small hole from titanium alloy (Ti-6: ASTM B348 Grade 5) by using 2.0 mm diameter of copper electrodes. In this experiment, the process parameters namely, current pulse off; maximum current and standard voltage level were selected to optimize. An orthogonal array L₉ was employed to analyze the material removal rate (MRR) of the copper electrode of diameter 2.0 mm penetration. The optimum EDM hole process can be established through this method and the major parameters that effect the MRR can be also detected and verified the effectiveness through experimental results.

Abstract: Cutting force is one of the most important parameters in the drilling process of FPC (Flexible printed circuit board). It has a directly affect on the micro-drills’ life and the micro-holes quality. It causes the FPC delamination, pulling of the plastic, the burr of exit hole and other processing defects. In this paper, some experimental investigations of cutting force of high speed micro-drilling are carried out to improve the drilling quality of FPC. The results indicate that the drilling parameters(spindle speed, feed speed and drill-bit diameter) have significant influence on micro-drilling thrust force. The thrust force of drill copper foil is larger than the thrust force of drill adhesiver layer and the thrust force of drill PI layer is the smallest. The larger the thrust force is, the bigger the exit burr is.

Abstract: Surface integrity is particularly important for the aerospace industry components in order to permit longer service life and maximized its reliability. This present work compares the performance of palm oil and synthetic ester on surface roughness, surface defect, microhardness and subsurface deformation when high speed drilling of Ti-6Al-4V under MQL condition. The drilling tests were conducted with AlTiN coated carbide tool. The surface roughness decreased with increasing in cutting speed and thicker subsurface deformation was formed underneath the machined surface. Grooves, cavities, pit holes, microcracks and material smearing were the dominant surface damages thus deteriorated the machined surface. For both lubricants, the machined surface experienced from thermal softening and work hardening effect thus gave a variation in microhardness values. The results indicated the substantial benefit of MQL by palm oil on surface integrity.

Abstract: This paper describes the results of application of different MQL liquids (synthetic ester and palm oil) to high speed drilling of Ti-6Al-4V. The investigation was focused on the surface integrity of the machined surface. It was found that palm oil could be a viable alternative to the synthetic ester for MQL liquid application.

Abstract: The Composites are difficult machining materials which widely used in aerospace industry due to their excellent mechanical properties. Tool wear and delamination are considered the major concern in manufacture the parts and assembly. The thrust force and torque affect the tool life and delamination mostly. This paper investigated the drilling force and torque of carbon fibred composite with carbide drilling tools and half core drilling tool. The experiments were carried out under air cooling cutting conditions and the drilling force using carbide tool and half core tool were compared and the experimental results indicated that the drilling forces using half core drill were smaller than that of using carbide tool.