Analysis of drilling surface microgeometry (original) (raw)
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Effects of drill microgeometry and cooling supply in the surface integrity
Purpose: The objective of this paper is to investigate the effect of drill microgeometry and cooling supply in the surface integrity of machined holes. The changes in the holes surface and subsurface due to differences on tools features were presented. Design/methodology/approach: Two types of carbide drills with differences in microgeometry and internal/external cooling were used in the machining of SAE 1045 steel. The surface integrity of the holes was evaluated in terms of surface and subsurface quality. The holes surface was examined using optical microscopy (texture) and roughness measurement. The subsurface analysis included plastic deformations, and micro and nanohardness. Findings: The differences in the cooling supply and drills microgeometry showed influence on surface integrity results. The drill type with internal cooling and improved microgeometry produced holes with a smoother surface and subsurface changes of lower magnitude. The most influent feature of microgeometry...
Effect of the Cutting Edge Preparation on the Surface Integrity after Dry Drilling
Procedia CIRP, 2014
Nowadays, cutting edge preparation is a widely applied tool improvement method, especially when concerns tool's life. However, the effects of the tool treatments on the generated hole surface are still an ongoing investigation. The machined hole is subject to severe contact with the tool, in particular the drill corner and guide, providing an increase of friction and thus, heat generation. Consequently, the surface integrity suffers several alterations. Therefore, this study aims to understand the effect of the cutting edge preparation on the surface integrity of holes. Experiments performed with carbide tools, coated with TiAlN and three configurations of tools (sharpened, polished with abrasive brushes and treated with drag finishing surface treatment) during dry drilling, showed that the tool condition has an important effect on the surface roughness, temperature and subsurface plastic deformation.
The influence of drill point geometry on tool life
Tehnički glasnik, 2018
Drilling is a cutting process that uses a rotary cutting tool to cut a cylindrical hole in a solid material. During machining, drill bits are exposed to rapid wear at high temperature. Sometimes, due to an ecological need for dry technology without any lubricant, the use of drill bits with coatings is required, typically titanium nitride (TiN), titanium carbon nitride (TiCN) or titanium aluminium nitride (TiAlN). This paper presents research on drilling done to determine how drill point geometry affects the drill lifetime and finished surface quality. We compared the chip removal ability and surface quality of bored holes in Hardox 500 created with high-speed steel drill bits and drill bits manufactured from hard metals, with and without coatings, under constant processing parameters. A cost/efficiency comparison was also carried out with respect to drill bit fabrication, sharpening, and use. Based on the data obtained on the damage drill points, the most economical drill bit for pr...
Effect of machining parameters on hole quality of micro drilling for brass
Modern Applied Science, 2009
This paper present the effect of drilling parameter such as spindle speed, feed rate and drilling tool size on material removal rate (MRR), surface roughness, dimensional accuracy and burr. In this work, a study on optimum drilling parameter for HSS drilling tool in micro-drilling processes in order to find the best drilling parameter for brass as a workpiece material. Micro drilling experiment with 0.5 mm to 1.0 mm drill sizes were performed by changing the spindle speed and feed at three different levels. The results were analyzed using microscope and surface roughness device. Comparatives analysis has been done between surface roughness, MRR and accuracy of drilled holes by experimentation. From the result, the surface roughness are mostly influenced by spindle speed and feed rate. As the spindle and feed rate increases, the surface roughness will decrease. The tool diameter gives less influence on the value of surface roughness. The value of MRR is decreased when the tool diameter, spindle speed and feedrate are decreases. As drilling tool diameter, feedrate and spindle speed increase the dimensional accuracy of drilled hole will decrease. The increment of spindle speed and feed rate value mostly will affect the tool wear and size of burr on the edge of drilled holes.
Drilling is most often associated with hole-making. The surface roughness parameters represent a measure of surface quality, and it is mainly influenced by the cutting process parameters (cutting speed, feed rate, drill diameter), tool geometry, tool material, tool type, type of processing, coolant and lubricating fluid, tool machine and type of work piece material. The purpose of this paper is to explore the effects of drilling parameters such as; cutting speed (v c), feed rate (f), drill diameter (d) and drill point angle (θ) on the surface roughness. There are different parameters used to estimate the severity of the surface roughness (Ra, Rz, Rq and Rt). The arithmetic average deviation Ra is commonly used for finish surface processing. The experimental plan was based on Box-Wilson Central Composite Design. First order model predicting equations for surface roughness have been established by using RSM methodology to collecting the experimental data, during machining of Ck45E ste...
2014
In these days, the key elements for the reliability and the safe operation of technical devices are the following: surface of the tools, the surface quality and the roughness of the connecting elements. The present work is going to introduce the idea that different machining methods that create microgeometries that are very much different from each other and of diverse roughness parameter proportions. It will be shown that the wear and the change of the tool edge(s)-resulting from the deterioration process of the tools, used during production-cause significant arithmetical, average and form deviations. The uncertainties of the roughness measuring technique, arising during the evaluation of the real and filtered surface profiles, will be shown via samples.
OPTIMIZATION OF PARAMETERS AFFECTING SURFACE ROUGHNESS AND HOLE DIAMETER IN BORING PROCESS.doc
Boring operation is performed on bucket Oriels of earth moving equipment. As in other machining operations, boring process is also influenced by multiple parameters like feed rate, depth of cut, type tool & coolant, speed of cutter, etc. The objective of the present work is to improve the quality of the surface finish (Ra) and the accuracy of bore diameter. The parameters considered for optimization of the boring process are speed and feed rate of the cutting tool, while the depth of cut maintained at a constant value of 1 mm. After the completion of the boring process, each individual Oriel is checked for surface roughness (Ra) and dimensional conformance. Experiments are carried out on 18 different samples (using full factorial). The response data in the form surface finish and diameter of the bore are obtained for each sample. The Analysis of Variance (ANOVA) is carried out to find the significant factors and their individual contribution on the response functions. The most optimal values for the given boring conditions of speed (1000 rpm), feed rate (100 mm/min) and depth of cut 1 mm expected to give a hole Dia 70.005 mm and surface roughness Ra 1.843 µm. The optimal values are further confirmed by carrying out nine confirmatory tests by three different operators. The results for all the three cases are closely following the optimal solution obtained by DOE process, indicating that the solution adopted is good for the given environment of boring operation.
ASME Journal, 2018
Analyzing the effect of cutting parameters on surface roughness and tool wear when machining nickel based hastelloy-276 Basim A Khidhir and Bashir Mohamed-Experimental investigation of various surface integrity aspects in hard turning of AISI 4340 alloy steel with coated and uncoated cermet Anshuman Das, S. K. Patel, Ch. Sateesh Kumar et al.-Study of ultrasonically assisted turning of stainless steel and brass alloys S M A Mahdy, M A Gouda and V V Silberschmidt-This content was downloaded from IP address 91.75.70.162 on 02/05 Abstract. Nickel based super alloys manufactured through powder metallurgy (PM) route are required to increase the operational efficiency of gas turbine engines. They are material of choice for high pressure components due to their superior high temperature strength, excellent corrosion, oxidation and creep resistance. This unique combination of mechanical and thermal properties makes them even more difficult-to-machine. In this paper, the hole making process using coated carbide inserts by drilling and plunge milling for a nickel-based powder metallurgy super alloy has been investigated. Tool life and process capability studies were conducted using optimized process parameters using high pressure coolants. The experimental trials were directed towards an assessment of the tendency for surface malformations and detrimental residual stress profiles. Residual stresses in both the radial and circumferential directions have been evaluated as a function of depth from the machined surface using the target strain gauge / center hole drilling method. Circumferential stresses near workpiece surface and at depth of 512 µm in the starting material was primarily circumferential compression which was measured to be average of-404 MPa. However, the radial stresses near workpiece surface was tensile and transformed to be compressive in nature at depth of 512 µm in the starting material (average:-87 Mpa). The magnitude and the depth below the machined surface in both radial and circumferential directions were primarily tensile in nature which increased with hole number due to a rise of temperature at the tool-workpiece interface with increasing tool wear. These profiles are of critical importance for the selection of cutting strategies to ensure avoidance/minimization of tensile residual stresses that can be detrimental to the fatigue performance of the components. These results clearly show a tendency for the circumferential stresses to be more tensile than the radial stresses. Overall the results indicate that the effect of drilling and milling parameters is most marked in terms of surface quality in the circumferential direction. Material removal rates and tool flank wear must be maintained within the control limits to maintain hole integrity.
Statistical Analysis of the Effects of Feed, Speed, and Wear on Hole Quality in Drilling
Journal of Manufacturing Science and Engineering, 1996
A statistical analysis of hole quality in drilling was performed. Using standard twist drills, holes were drilled dry in hot rolled steel. The effects of feed and speed on the hole quality features of oversize, out-of-roundness, location error, angularity error, and taper were examined using a full factorial analysis of variance. The effects of workpiece surface condition, geometrical variation among drills, and drill wear were qualitatively observed. The results showed that feed and speed have a relatively small effect on the measured hole quality features. With the exception of hole location error, the hole quality was not predictably or significantly affected by the cutting conditions. Although these results were not expected, they have the important positive implication that production rates may be increased without sacrificing hole quality. The drilling feeds and speeds would be constrained by factors other than hole quality, such as drill wear, drill breakage, or force, torque...
DAAAM Proceedings, 2016
The optimization of surface integrity in drilling process using response surface method (RSM) is presented. This paper investigates the machining parameters affecting the roughness of surfaces produced in dry drilling process. Three parameters were selected for study: cutting speed, feed rate and drill diameter. In this study developed a model of surface roughness based on the response surface method, logarithmic linearized approach for determining the processing parameters in drilling process of steel EN 1.0038, using HSS coated TiN drill tools. The experiment has been designed and carried out on the basis of a three level factorial design. Obtained results are in good accordance with the experimentally obtained data, confirming the effectiveness of regression analysis in modeling of surface roughness in the dry drilling process. The established predictive model shows that the surface roughness increases with the increase of feed rate and depth of cut but decreases with cutting speed increase.