Papers by Keyword: Burr Height

Abstract: Drilling Aramid Fiber Reinforced Plastic (AFRP) with aluminium (AL7075-T6) is challenging. It is crucial to maintain the dimensional accuracy and minimize burr formation. In this study, two carbide drill bit were tested across 13 runs with varying combinations of feed rates (0.05, 0.08, 0.10 mm/rev) and spindle speeds (2000, 4000, 6000 rev/min), using a central composite design (CCD) methodology within the Design of Experiment (DOE) framework. The drill geometries included angles such as the helix angle, primary clearance angle, chisel edge angle, and point angle. For the tapered web drill bit, angles were set at 10º, 6º, 45º, and 130º, while for the burnishing drill bit, they were 20º, 8º, 30º, and 135º, respectively. The primary focus of the experiment was to assess hole quality, specifically evaluating hole diameter error and burr height formation. Among the 13 runs conducted, the tapered web drill bit exhibited superior performance in terms of hole diameter error, showing a deviation of-0.5 µm in Run 8, compared to a deviation of 1.2 µm for the burnishing drill bit in Run 12. Additionally, the tapered web drill bit demonstrated a lower burr height of 63.97 µm in Run 12, while the burnishing drill bit resulted in a burr height of 95.44 µm in Run 4. These findings enhance aircraft production by promoting better hole quality with optimal drill bits, leading to material savings, lower rejection rates and cost reduction, thus boosting reliability and productivity.

Abstract: In past few decades, a lot of research has been done in the field of machining to improve the quality of machined surface. Out of these machining operations, drilling is widely used in the areas of marine and aerospace for assembly requirements. Titanium alloy Ti-6Al-4V, owing to its vast applications, is regarded as an important material for these industries. Ti-6Al-4V is categorized as difficult to machine material. Based on above stated facts, an experimental study was conducted on the dry drilling of Ti-6Al-4V. The objective of this study was to establish the correlations between drilling parameters such as feed rate and spindle speed, and quality of machined surface which is evaluated in terms of drill hole diameter deviation, exit burr height and surface roughness.

Abstract: This study presents an experimental investigation on the effects of cutting speed, feed and percentage of alumina particle on the burr height in drilling of Al 6063 reinforced with Al₂O₃ and Gr particles using solid carbide twist drills of 6 mm diameter. Taguchi method with three factors at three levels is employed to analyze the drilling characteristics of these composites. For all cutting conditions, Al 6063/6%Al₂O₃/1%Gr composite has lower burr height values than other fabricated composites. The results revealed that exit hole burr height are greatly influenced by the feed rate rather than the speed for all the samples of hybrid composites.

Abstract: Due to the high precision and strong molding capacity, micro-milling plays an important role in the field of micro-machining. The components machined in micro-machining is smaller than conventional components, and sometimes the generated burrs are as large as the feature size of components, so the study of micro burr control is very important. In the reseach, cutting-direction burrs are based on the traditional milling characteristics, also combined with the characteristics of micro-milling. The experimental data verify the correctness of the model well, so it provides theoretical guidance for the burrs control in micro-milling.

Abstract: The micro patterning on a cylindrical surface is conventionally carried out by electrochemical machining, chemical etching, cutting and so on. However, there exists some problems in machining dimensional errors and tool lives. On the other hand, blasting is expected as one of micro fabrication methods and progresses to apply for machining of hard and brittle materials. The purpose of this study is to develop the micro blasting technique for patterning of micro herring-bone grooves on spindle surfaces of the fluid dynamic bearings. Then, machining characteristics in blasting of rotating workpieces are experimentally investigated, analyzing stock removals, burr heights and groove shapes. In addition, micro herring-bone grooves are patterned on spindle surfaces by blasting and the performance of herring-bone bearings are evaluated. The herring-bone bearings with micro grooves patterned on a spindle surface by blasting have enough performance, compared with conventional ones.

Abstract: Burr in drilling plays an important role on product quality, so analysis the burr size is essential at the final production. This paper presents the application of Taguchi method for survey the burr height and burr thickness by adding ultrasonic vibration to the process. In this paper L18 orthogonal array based on Taguchi techniques was used in the design of experiments. Analysis of Variance (ANOVA) was used to determination the effect of drilling parameter on burr formation. Influence of cutting speed, feed rate and percentage of SiC particle was investigated in with and without Ultrasonic assisted drilling. Al/SiCp MMC with 5, 15 and 20 wt% of particulate SiC in dry drilling operation with TiN coated drill tools were investigated.

Abstract: In this paper the characteristics of pulse electrochemical deburring (PECD) is analyzed through a developed mathematical model and main influencing factors such as applied voltage, pulse duty factor, deburring time, initial burr height and initial interelectrode gap on burr height have been analyzed. The paper also highlights the scheme of the developed PECD system designed to operate within the parametric limits. The calculated results obtained from the mathematical model are found to be approximately consistent with the experimental results. The results show that initial burr height h₀=0.057mm is removed, and the fillet radius R=0.248mm is obtained. The present paper through various parametric studies will act as a guideline for the operation of a PECD system.

Abstract: This paper discusses burr formation in micromilling of AISI 304 stainless steel. Chip load, cutting speed and the application of coolant were chosen as the milling parameters. Experiments were conducted using 500 µm diameter tungsten carbide end milling tool. Milling parameters and measured burr height values were analyzed and statistical models were developed for the estimation of burr height. The models showed that the chip load and cutting speed both have direct and interactive contribution to burr formation. When micromachining without coolant, the burr height increases about 40% compared to that of machining with coolant. The optimized values of chip load and cutting speed were found to be 1 µm/tooth and 78 mms-1 respectively. The predicted burr heights were 5-7% larger than that of measured values.