Design and simulation of dust extraction for composite drilling

Journal of Manufacturing Processes, 2007

The generation of fine dust during dry machining is a serious problem both for the environment and for workers. During machining, the fine dust particles generated remain suspended in the air for long periods, during they can be inhaled by workers. The quantity of dust generated is influenced by factors such as material type and heat treatment condition, temperature, and the associated chip formation mode. The aim of this work is to discover how these parameters influence dust generation during dry machining, which could lead to the control of dust production in the future. The materials tested are the wrought 6061 and foundry A356 aluminum alloys and 70-30 brass. It is found that pre-cooling a workpiece material leads to changes in chip formation, in the reduction of cutting forces, and hence in a reduction in fine dust generation by at least 70%, depending on the materials and cutting conditions used. Also, preheating the workpiece increases chip ductility and dust production levels.

This paper presents the particle-size distribution of dust created by the drilling of selected wood composites, which was carried out using a CNC machine. The particle-size distribution was studied through two methods. Two analyses were performed: the sieve analysis of samples from the whole mass of collected dust and the laser diffraction analysis of the finest fraction isolated by sieving. The results presented general information about the particle-size distribution of the dust, as well as detailed information on the content of the finest particles. This information revealed that the particles might pose a potential risk to the health of workers employed in the woodworking industry. This potential risk is due to the possibility of their dispersion in the atmosphere surrounding the workplace and their size, which allows them to be respirable. The relationship between the fineness of the dust and the type of wood composite was also tested. Most ultrafine particles are formed during the drilling of fibreboards and are especially produced in traditional wet technology.

This paper dealt with an attemp to overcome dust problem to improve health in working area. Dust are side product of machining process in jewellery master machining using CNC. Resin material is showing good performance to be used as jewellery master material. Its machineability resulting high quality surface when machined using CNC. Unfortunately, its small size and light density resulting very light tiny dust that able to pass-through the vaccuun cleaners filter. Moreover those dust are fly to anywhere and makes working area become dirty and severe for respiratory problem. In this paper, cyclone method is discussed to trap dust into chambers. Multiple cyclones is used to increase efficiency of filtering mechanism. As a result an alternative filter is introduced but it can only reduce about 60% of dust.

IRJET, 2020

This paper discusses the influence of cutting parameters in drilling of Delrin material. The experiments are conducted to study the effect of drill diameter, point angle, spindle speed, feed rate and depth of cut on material removal rate using HSS twist drills. In this thesis, the input parameters considered are point angle, tool diameter, spindle speed, feed rate and depth of cut. Different combinations of the above parameters are considered to get the maximum material removal rates using L12 orthogonal array in Taguchi method. The parameters are drilling diameter of cutting tool-6mm, 10mm, point angle-118˚ & 120˚, Speed-800rpm, 1200rpm, Feed Rate-30mm/min, 50mm/min and depth of cut-0.5mm, 1mm.Theoretical calculations are done to calculate to verify the Material Removal Rate (MRR) and calculating time taken has been calculated by the experiment. Experiments are conducted on CNC milling machine using Taguchi design of experiments a model is developed with the drilling parameters. The experimental results were analyzed using MINITAB V19. By observing the Taguchi results to optimize parameters for time taken for drilling, the optimum speed is 1200rpm, feed rate is 50mm/min, depth of cut is 0.5mm, tool angle is 118 0 and drill diameter is 6mm. Signal-to-Noise (S/N) ratio is employed to analyze the effect of drilling parameters on the quality of the drilled holes.

International Journal of the Physical Sciences, 2012

A study was carried out to analyze the particles produced during drilling process with twist drills with one and two spirals (length 70 mm, diameter 8 mm) with different feeding speeds, executed in beech (Fagus sylvatica), pine (Pinus sylvestris) and oak (Quercus petraea) woods, and also, medium density fiberboard (MDF), particleboard and poplar plywood panels. Drilling of solid woods was performed by following its longitudinal and transversal directions. The measurement and counting of wood dust particles was performed with a Particle Scan Pro instrument that measures the concentration of wood dust particles (milligrams per cubic meter or particles/l) present in the air. This instrument is able to count particles with diameter equal to and larger than 0.3 μm. A total of 281 tests were made with an average number of repetitions of eight for each material. The larger quantity of particles was produced by the wood-based panels, followed by hardwoods and finally, softwood. All drilled woods produced more particles on the longitudinal direction than on the transversal direction. For lower feeding speed, the number of particles increased with the increase of the number of bit's spirals. In general, the bits with one spiral produced a smaller number of pending particles than two spirals bits. Most of produced particles were registered in small sized categories (≤ 1 μm Ø), where most of them were occupied by micro fines particles with 0.3 to 0.5 μm diameter, which were produced massively during V 2 2 b work regime.

Journal of Materials Processing Technology, 2018

Electrical discharge machining (EDM) is a non-contact machining process that removes material through spark erosion and is often used for drilling holes in difficult-to-cut materials such as Nickel-based super alloys. However, this process becomes slower with the increase of the hole depth. This is because the flushing pressure becomes inefficient for the effective evacuation of process debris leading to secondary discharges and resulting in increased machining time. This study presents an innovative simultaneous flushing and vacuum-assisted debris removal system, which facilitates better debris removal for deep-hole EDM drilling. Improvement in the drilling time and better surface roughness have been achieved using the developed setup. To evaluate the performance of the vacuum-assisted debris removal system, a novel computational fluid dynamics model is also proposed in this study. Experimentally measured particle size data of full length scale act as a reference for the proposed numerical model.The analysis presented in this study provides significant insight into sizes of the debris particles in different machining conditions, in full length scale using an automated image processing technique. The presented numerical model can be used to investigate the various factors influencing the removal of debris from the machining zone. The experimental and numerical components of this research complement each other in the design of the presented vacuum-assisted debris removal system.

Science and Engineering of Composite Materials, 2021

Metal-composite laminates and joints are applied in aircraft manufacturing and maintenance (repairing) using aluminum alloys (AA) and glass fiber-reinforced polymer (GFRP). In these applications, drilling has a prominent place due to its vast application in aeronautical structures’ mechanical joints. Thus, this study presents the influence of uncoated carbide drills (85C, 86C, H10N), cutting speeds (v c = 20, 40, and 60 m min−1), and feed rates (f = 0.05, 0.15, and 0.25 mm rev−1) on delamination factor, thrust force ( F t {F}_{\text{t}} ), and burr formation in dry drilling metal-composite laminates and joints (AA2024/GFRP/AA2024). Experiments were performed, analyzed, and optimized using the Box–Behnken statistical design. Microscopic digital images for delamination evaluation, piezoelectric dynamometer for thrust force acquisition, and burr analysis were considered. The major finding was that the thrust force during drilling depends significantly on the feed rate. Another signific...

Advances in Materials Science and Applications, 2014

In most drilling applications, pre-holes are often performed prior to the final hole drilling in order to obtain holes with good quality (dimensional accuracy, surface finish, and reduced burr). While this operation can improve the process stability, it might however also have an impact on process performance indicators such as dust emission, energy required for the drilling process, cycle time and chip breakability. This work investigates the effects of pre-holes on cutting forces, chip formation, surface finish and dust emission. Aluminum alloys (6061-T6 and 7075-T6) were drilled at different cutting speeds using uncoated HSS drills and the thrust forces, dust emissions and surface finish were analysed. It was found that drilling with pre-holes reduced the cutting forces, improved hole surface finish and chip breakability, and increased the total amount of metallic particle emission.

Mining Science and Technology, 1991

The aim of this work was to investigate the size distribution of dust particles produced during the drilling process. It has already been proved that the degree of harmful effect of inhaled dust is closely related with dust particle size. The dust data needed to determine size distribution were obtained by sampling dusty atmospheres during the drilling process with a short-period thermal precipitator. Drilling and dust sampling processes were carried out in a model gallery which simulated the working face. Rock samples used in drilling were brought from the various galleries of Kozlu mines, Zonguldak Colliery. The tests were carried on four types of sandstones, two types of shales and conglomerate, in total seven types of sedimentary rock. For each type of rock six dust samples were taken and evaluated. It is concluded that the frequency distribution of airborne dust particles produced by each rock type is approximately lognormal. The geometric mean values of dust particles for sandstone, shales and conglomerate are found to be 0.89.0.95 and 0.83/~m respectively. In other words, the mean value of dust particles produced during the drilling operation of different rocks are around 1/tm in diameter, which has the maximum probability to be retained in the lungs during respiration.

SAE Technical Paper Series, 2008

This work aims to study the drilling dry process in the aircraft structures. In the first stage were used helical speed steel drills with different geometries. This was used various combinations of cutting parameters. The power cut was monitored by sensors connected to the machine tool. The burr were measured and evaluated in accordance with the terms of cut. The structure deformation and the roundness of the holes were evaluated. Based on preliminary results, there is a need to replace the process of drilling using drills by helical interpolation milling. The second stage was used the same method of evaluation.