Effect of machining parameters on hole quality of micro drilling for brass (original) (raw)
Related papers
An Experimental Investigations on Machining Parameters in Micro-drilling Process
2017
Under various fundamental machining process Drilling is one of them. For getting holes below 1mm Micro Drilling process which is high precision process are preferred. It is used for the purpose increasing quality of special parts and items. Along with high precision it is also preferred for high spindle speed application to improve productivity and quality. It has an attractive applications like Printed circuit boards, Fuel injection nozzles, Watch parts, Camera parts, Medical needles, Aeronautics, Mobilephones, Computerset. One of the major goal in machining operation is material Removal Rate . This paper deals with how the MRR can be optimized considering the input parameters like, speed, feed and depth of hole and Investigation had done by Designing Experiment in Taguchi and Analyzing using ANNOVA and signal to noise ratio. Taguchi method not only optimize quality characteristics through the setting of design parameters, but also reduce the sensitivity of the system performance t...
A review on Optimization of material removal rate in micro-drilling process
2015
Introduction Drilling is one of the basic technology.Micro Drilling is high precision process for smaller holes below 1mm.It is used for the purpose increasing quality of special parts and items. The price of a micro-drill cutting tool itself is relatively low, the costs caused by tool failures are considerably higher.Material removal rate is one of the major manufacturing goal in machining operations. Taguchi method is a well known experiment design method applied in many industries to optimize quality characteristics through the setting of design parameters with orthogonal array, followed by optimization of the Fuzzy parametric deduction to improve MRR. II. Micro Drilling Micro drilling small diameter presents greater problems since coolant fed drills cannot be used and high spindle speeds are required. High spindle speeds also require the use of balanced tool holders Micro drilling is characterized not just by small drills but also a method for precise rotation of the micro drill and a special drilling cycle. In addition, the walls of a micro drilled hole are among the smoothest surfaces produced by conventional processes. This is largely due to the special drilling cycle called a peck cycle. The smallest micro drills are of the spade type. The drills do not have helical flutes as do conventional drills and this makes chip removal from the hole more difficult. Drills with a diameter of 50 micrometers and larger can be made as twist drills. Drills smaller than this are exclusively of the spade type because of the difficulty in fabricating a twist drill of this size.[2] Drilling may affect the mechanical properties of the work piece by creating low residual stresses around the hole opening and a very thin layer of highly stressed and disturbed material on the newly formed surface. This causes the work piece to become more susceptible to corrosion at the stressed surface. A finish operation may be done to avoid the corrosion. Zinc plating or any other standard finish operation of 14 to 20 µm can be done which helps to avoid any sort of corrosion. For fluted drill bits, any chips are removed via the flutes. Chips may be long spirals or small flakes, depending on the material, and process parameters. The type of chips formed can be an indicator of the mach inability of the material, with long gummy chips reducing mach inability.[8] The recommended speeds and feeds for micro drilling are as varied as the materials which can be drilled. Micro drilling is not generally a high speed process since dwelling of the drill at the bottom of the hole can cause hardening of the work piece leading to increased drilling forces. For most metals, typical spindle speeds are in the 2000 to 4000 rpm range and feeds are in the range of a micrometer per revolution, or so. Care must be taken when drilling plastics to avoid melting of the material which can lead to adhesion of the plastic to the drill. This can cause drill breakage or poor sidewall smoothness.[7]
High precision and high spindle speed applications is one of the most significant factors in fundamental technologies in machining processes, which is of good productivity and quality. When the basic machining process, 'drilling' is performed below 1mm hole diameter, it is called, " Micro-Drilling " , which is the precision hole drilling process. This study deals with Response Surface Methodology approach in Micro-drilling machine for optimizing the material removal rate. Drilling is performed on Brass material with machining parameters as Feed, Speed, Machining time and Depth of hole. The experiments were conducted with Box-Behken Design method based on response surface design. Analysis of variance (ANOVA) was used to determine the effect of the parameters after getting the values of MRR. The interaction of their parameters was also considered to be important. Regression analysis was performed and for MRR, a Linear model was fitted. This was done considering the significant interactions and the parameters. Finally, optimization was performed using desirability approach and experiments for confirmation were conducted.
Analysis of drilling surface microgeometry
The improving quality of hole boring, primarily by tool innovation activities, allows us to use drilling as a finishing technology. It is well known that the attainment of a perfect chip-forming ability poses an enormous technical challenge to developers. In order to succeed in this challenge, in practice it is not enough to reach a sufficient cutting condition be sides the right combination of the construction-geometry-coating triple. However, any chip forming disorder will significantly influence the quality of the machined surface. The wear resistance of the surfaces and their adequate functional behavior are definitely linked to surface quality parameters. It is well known that the lifetime of parts and their functional behavior and reliability depend, besides shape and bore accuracy, on the deviation of the microgeometry of the machined surface (waviness (W) and roughness (R)): on surface quality in a broader sense. For an accurate evaluation of the surface profile, typical descriptive parameters have to be analyzed in a complex manner. It is not enough to deal with the roughness (R) profile, but the unfiltered (P) profile should rather be focussed on. I.
Analysis of Micro-Drilling Process Using Response Surface Methodology
2017
In current scenario micro drillings have a great influence for manufacturing to apply special parts and items. The micro drill tools play a critical role is increasing the productivity of a cutting process. One of the most important factor in fundamental technologies in machining processes is high precision and high spindle speed applications with good quality and productivity. Drilling is the basic machining process, when it is performed below 1mm hole diameter then it is called Micro-Drilling, which is the precision hole drilling process. Many researchers had worked on Micro-drilling for analyzing behavior of drill tool , torques,thrust forces, stresses etc.also optimization works are carried out but the drill diameters considered were from 0.6mm to 1mm. while below that the process had carried out on Non-conventional machining processes. This research paper deals with Response Surface Methodology approach for optimizing the material removal rate in Micro-drilling machine for dril...
Journal of Mechanical Engineering Research and Developments, 2019
In manufacturing, the quality of holes produced is very important. For instance, the hole size may determine the ability of two parts to be assembled. At the same time, the hole surface may also contribute to the ease in assembly process. However, the quality of holes produced in drilling operation is affected by drilling parameters such as the drill speed and feed rate. Therefore, it is necessary to determine the suitable drilling parameters' setting such that optimum hole quality can be achieved. This project aimed to determine the effect of drill speeds and feed rates on material surface roughness and radius accuracy. The experiment was designed based on the Taguchi method. The drilling operation was conducted using Okuma CNC milling machine on mild steel plate with different settings of spindle speeds and feed rates. The experimental results showed that the spindle speed affects significantly the surface roughness and radius accuracy. Whereas, the feed rate is only affect significantly the surface roughness. Besides, it is found that the optimum spindle speed and feed rate are 500 rpm and 150 mm/min to produce the minimum surface roughness. At the same time, the analysis also shown that the optimum spindle speed and feed rate to produce maximum radius accuracy are at 2000 rpm and 150 mm/min.
Diarotech is Belgian company specialized in manufacturing all types of cutting inserts for various industries. Diarotech is developing new drilling tools, in different sizes and geometries, by implementing various metallic matrix developed by the technology of powder metallurgy to include synthetic diamonds of different grit sizes and variable forms. Current developments require the evaluation of the tools performances in order to obtain effective tools. The Civil Engineering Department of the University of Mons has developed in recent years a micro-drilling testing bench originally dedicated to the characterization of the mechanical properties of geomaterials encountered in the sector of the construction or the restoration of the cultural heritage. This testing bench has been modified and adapted in the context of the "Nanofor" research project to test small drilling bits developed by Diarotech. The goal of the project is to define the most adapted drilling parameters for...
Parametric Optimization of Tool Wear Rate in Micro Drilling of Maraging Steel 300 Alloy
Reason-A Technical Journal, 2016
ABSTRACT Micro EDM, a variant of Electrical Discharge Machining (EDM) process, is used to drill micro holes in hard and electrically conducting materials. Since Maraging Steel 300 alloy has not been studied on micro EDM process, an attempt has been made in this research paper to investigate the effect of various process parameters on tool wear rate (TWR) in micro EDM drilling of holes in Maraging Steel 300 alloy using Taguchi Methodology. Process parameters taken up for study are Pulse-on time, Pulse-off time, Tool diameter and current. Brass electrode of 300 μm, 400 μm and 500 μm diameter is used as tool material. The experiments were carried out using L9 (34) orthogonal array. Based on eroded length of tool and volume measurements, the tool wear rate is calculated for various combinations of factors and levels. The results of experiments are thoroughly discussed and the effect of process parameters on tool wear rate is presented.
A review of modern advancements in micro drilling techniques
Journal of Manufacturing Processes, 2017
The demand for micro drilling with a diameter in a range of a few microns to several hundred microns is increasing in industries such as electronics, aerospace, medicine and automobiles, due to a significant uptake in the use of miniaturised products and devices. In order to satisfy the demand, a number of different micro drilling techniques have been developed. There has been, however, no report which explains, compares and contrasts all of these micro drilling techniques. This study examines the lasts micro drilling methods and techniques, categorises them into different groups, highlights recent developments and new trends, and depicts the future requirements in the field of micro drilling. Both conventional and non-conventional micro drilling techniques used in modern age applications are categorized. Conventional micro drilling makes use of drill bits of different configurations such as twist, spade, D-shaped, single flute, compound drill and coated micro drill, while non-conventional micro drilling involves electrical, chemical, mechanical and thermal means which include laser, EDM, ECM, SACE, electron beam, ultrasonic vibration or combinations of these approaches. We present here, a comparative study of conventional and non-conventional micro drilling techniques in order to show the potential and versatility of various micro drilling methods.
Towards the Prediction of Micro-EDM Drilling Performance on WC Varying the Hole Depth
Manufacturing Technology
The present work deals with the execution of through micro-holes on tungsten carbide plates using a micro-EDM (Electrical Discharge Machining) machine. The investigation focuses on the monitoring of the performance during the drilling phase in order to obtain the in progress behavior of the performance indexes. The experiments were carried out by varying some process parameters such as peak current, voltage and frequency to achieve both high and low power discharge conditions. Regarding electrodes, the most commonly industrial used ones were selected: tubular tungsten carbide and brass. The performance indexes taken into account were machining time, Material Removal Rate (MRR), Tool Wear (TW) and Tool Wear Ratio (TWR). Brass electrode always resulted to be the best solution in terms of drilling speed even though the wear of this electrode type is remarkable higher than the tungsten one. The evolution of the performance indexes during the drilling operation showed the same trend for both electrodes: increasing the hole depth, the drilling operation proceeds in a more difficult way, due to the evacuation of debris that becomes more difficult and therefore the performance indexes get worse. Finally, the technology windows of the cumulated MRR and TWR were defined for both electrode materials, in order to predict the micro EDM process performance varying the hole depth.