Circularity Error Research Articles

Geometrical improvement in machined micro-hole using adaptive tool feed system in electrochemical based discharge machining

Electrochemical based discharge machining (ECDM) removes the material by utilizing the thermal heating of the sparks followed by the chemical action. The tool feed method in ECDM controls the geometrical accuracies since gravity assisted and constant tool feed results in tool contacts that further deteriorates the micro-hole geometry. Moreover, high number of thermal cracks are produced with these tool feed methods.The present study investigates the adaptive tool feed system that withdraws the tool in upward direction when its contact with the work material is observed. Adaptive tool feed results in minimum tool contact and enhances the geometrical accuracies of the micro-holes. Hole circularity error (HCE) is taken as the response parameters for investigating the geometrical accuracies. The microscopy images reported a significant improvement in the geometry of the micro-holes machined with adaptive tool feed when compared to other tool feed methods. An improvement of 43.7% in HCE is acquired with the application of adaptive tool feed at 40 V. Moreover, the effect of input parameters on geometrical characteristics in terms of HCE is also discussed. The present study successfully reports the geometrical improvement of micro-holes in ECDM.

Analysis of Hole Quality and Chips Formation in the Dry Drilling Process of Al7075-T6

Millions of holes are produced in many industries where efficient drilling is considered the key factor in their success. High-quality holes are possible with the proper selection of drilling process parameters, appropriate tools, and machine setup. This paper deals with the effects of drilling parameters such as spindle speed and feed rate on the chips analysis and the hole quality like surface roughness, hole size, circularity, and burr formation. Al7075-T6 alloy, commonly used in the aerospace industry, was used for the drilling process, and the dry drilling experiments were performed using high-speed steel drill bits. Results have shown that surface roughness decreased with the increase in spindle speed and increased with the increase in the feed rate. The hole size increased with the high spindle speed, whereas the impact of spindle speed on circularity error was found insignificant. Furthermore, short and segmented chips were achieved at a high feed rate and low spindle speed. The percentage contribution of each input parameter on the output drilling parameters was evaluated using analysis of variance (ANOVA).

Evaluation of the Surface Defects and Dimensional Tolerances in Multi-Hole Drilling of AA5083, AA6061, and AA2024

Drilling is one of the most performed machining operations for riveting and assembly operations in many industrial sectors. The accuracy of the drilled holes and their surface finish play a vital role in the longevity and performance of the machined components, which, in turn, increase productivity. Therefore, this study investigated the effect of the multi-spindle drilling process on dimensional hole tolerances, such as hole size, circularity, cylindricity, and perpendicularity. In addition, the surface defects formed in the holes were examined using scanning electron microscopy. Three aluminium alloys, AA2024, AA6061, and AA5083, which are commonly used in the aerospace, automotive, and marine sectors, were chosen as the study materials. The results showed that the holes drilled in AA2024 gave less circularity error, cylindricity error, and perpendicularity error. In the case of hole size, the holes drilled in AA6061 were less deviated from the nominal size following holes drilled in AA2024 and AA5083 alloys. Surface damage in the form of metal debris adhesion, smeared material, side flow, and feed marks was found on the inner hole surface. Holes drilled in AA5083 alloy had the worst surface finish and were the most oversized, which was associated with noticeable damage and deformations in their inner surface. The ANOVA results revealed that the spindle speed was more influential than feed and mainly affected the hole size and cylindricity errors. However, in the case of circularity error and perpendicularity error, drilling parameters were found to be insignificant.

Prediction of drilled hole quality in bidirectional woven carbon fiber reinforced plastic using wavelet packets of force–torque signals

Drilling of fibrous composites like carbon fiber reinforced plastics (CFRPs) is always considered a grim job to perform owing to its abrasiveness and inhomogeneous properties. Compared to the available studies, the present work addresses the parametric investigation on drilling capability of TiAlN- and TiN-coated drills over the uncoated one. The delamination factor, surface roughness, and circularity error in CFRP were considered as the quality features. The acquired thrust and torque were analyzed in the time domain as well as the time–frequency wavelet field, followed by a sensitivity analysis between decomposed original force–torque signals in different phases. Finally, an attempt was made to improve the predictability of drilled hole quality using decomposed wavelets of force and torque extended to hybrid force–torque wavelets of the best features to the developed regression models. The feed rate was more predominant than spindle speed on delamination evidenced by higher axial thrust particularly using coated tools. However, the coated drills generated more uniform torque than the uncoated drills and improved the drilled hole quality as well. The torque wavelet was a better indicator of hole surface integrity than force wavelets in which intermediate frequency band torque and low-/high-frequency band force wavelets were found to be more significant.

Experimental modeling and optimization of surface quality and thrust forces in drilling of high-strength Al 7075 alloy: CRITIC and meta-heuristic algorithms

Al 7075 is a renowned high-strength engineering material used in automotive and aerospace applications, wherein many functional cylindrical parts are subjected to internal or external loads. Engineered parts with form errors (cylindricity CE and circularity error Ce) result in undesirable vibration and high deformation in rotating parts. In addition, reduced surface roughness (SR) and thrust forces (TF) are essential to limit the secondary process (namely, polishing) and power consumption. Experiments are performed based on central composite design considering drilling parameters (point angle, cutting speed, and feed rate) as inputs and output performances as CE, Ce, TF, and SR. It is noted that, except feed rate for Ce, all other parameters are found significant toward the output performance. Also, prediction accuracy with ten random experimental cases resulted with the percent error of 8.4% for SR, 5.41% for TF, 10.64% for Ce, and 10.35% for CE, respectively. Continuous ribbon-like chips at higher cutting speed, loose fragmented chips at higher feed rate, and increased arc length and radius at higher point angle were observed from the chip morphology analysis. Criteria importance through inter-criteria correlation (CRITIC) method applied to determine the weight fractions for Ce, CE, TF, and SR was found equal to 0.2802, 0.1991, 0.3293, and 0.1914, respectively. Four algorithms (genetic algorithm GA, particle swarm optimization PSO, teaching learning-based optimization TLBO, and JAYA algorithm) were applied to determine the optimal drilling conditions. JAYA algorithm determined optimized drilling conditions ensure predicted output values found close to experimental values with an acceptable percent error of 10.8% for Ce, 8.9% for CE, 6.73% for SR, and 3.51% for TF, respectively.

Investigating the Efficacy of Adhesive Tape for Drilling Carbon Fibre Reinforced Polymers

In the present research work, an effort has been made to explore the potential of using the adhesive tapes while drilling CFRPs. The input parameters, such as drill bit diameter, point angle, Scotch tape layers, spindle speed, and feed rate have been studied in response to thrust force, torque, circularity, diameter error, surface roughness, and delamination occurring during drilling. It has been found that the increase in point angle increased the delamination, while increase in Scotch tape layers reduced delamination. The surface roughness decreased with the increase in drill diameter and point angle, while it increased with the speed, feed rate, and tape layer. The best low roughness was obtained at 6 mm diameter, 130° point angle, 0.11 mm/rev feed rate, and 2250 rpm speed at three layers of Scotch tape. The circularity error initially increased with drill bit diameter and point angle, but then decreased sharply with further increase in the drill bit diameter. Further, the circularity error has non-linear behavior with the speed, feed rate, and tape layer. Low circularity error has been obtained at 4 mm diameter, 118° point angle, 0.1 mm/rev feed rate, and 2500 RPM speed at three layers of Scotch tape. The low diameter error has been obtained at 6 mm diameter, 130° point angle, 0.12 mm/rev feed rate, and 2500 rpm speed at three layer Scotch tape. From the optical micro-graphs of drilled holes, it has been found that the point angle is one of the most effective process parameters that significantly affects the delamination mechanism, followed by Scotch tape layers as compared to other parameters such as drill bit diameter, spindle speed, and feed rate.

A novel methodology of Combined Compromise Solution and Principal Component Analysis (CoCoSo-PCA) for machinability investigation of graphene nanocomposites

The interest in the application of Graphene oxide/polymer nanocomposites is recently rising in various industries such as drug delivery, bioimaging, aircraft structures, sensors, battery application, etc., due to the improved features of Graphene oxide. The machining behavior of polymers is remarkably different from metallic alloys due to anisotropic and high synergistic effects. This article investigates the machinability aspect and machining response optimization of the developed hybrid nanocomposites. The drilling responses, namely, average surface roughness (Ra), Mean roughness depth (Rz), and Circularity error (Ce), were optimized by using the integrated approach of Combined Compromise Solution and Principal Component Analysis (CoCoSo-PCA). Response Surface Methodology (RSM) array is utilized to execute the drilling tests. The optimal setting is obtained as drill speed 2400rpm, feed 80mm/min, 1 weight% of Graphene oxide (G%). The feed rate shows a primary role in controlling both the surface roughness indices and Circularity error. The high feed value affects the development of the drilling-induced defect and cracks. The SEM analysis of the machined samples was performed to check the machined hole quality and surface finishing. ANOVA estimates the model adequacy of the proposed hybrid model. The obtained results have been validated by a confirmatory test, which proves the proposed hybrid module practicality in the manufacturing environment. Besides, the proposed approach is compared with the recently developed optimization modules to evaluate the application potential.

Mathematical Analysis of Process Parameters in Drilling of Various Aluminium Matrix Composites Using TOPSIS

Drilling is one of the major material removal processes to produce holes and the key parameters involved in the process are speed of the drilling tool and feed rate of the tool into the work piece to be machined. A conventional study would include the diameter of the drill bit as a key geometric feature that affects the output parameters: thrust, torque, roundness error and the surface roughness. Drilling experiments are performed on three different hybrid composite specimen of Al6061 alloy. Keeping the diameter constant and by varying the point angle of the tool, drilling is performed and the responses of the output parameters are recorded and tabulated. Using the data from the experiment, analysis of the data is done by one of the multi-criteria decision analysis method, TOPSIS. This method is used to determine the optimal condition to drill a particular specimen of the composite. In TOPSIS method, the data is ranked based on performance of the drill, to find the parameters which are ideal to obtain a hole with minimum roughness, circularity error and thrust force. But it is enough to keep the goal as minimum roughness because the other parameters will invariably get minimized as they are dependent

WITHDRAWN: Machinability study and optimization of CNC drilling process parameters for HSLA steel with coated and uncoated drill bit

This research focused to find the machinability characteristics of the HSLA steel by the way of using CNC drilling machine. Drilling is the method of production of a hole used in a assembly section of industries and the parts fitting in the machine. In this study two types of drill bits are used to evaluate the machinability study of HSLA steel, the drill bits are High speed steel and coated drill bit TiALN- Titanium aluminium nitride. Both drill bits are used to make a drill effectively and compare the result of surface roughness and circularity error. The optimization process is considered to minimize the surface roughness and circularity error, the process parameters are chuck speed of 800, 1000 and 1200 rpm, feed rate of 0.04, 0.06 and 0.08 mm/rev and depth increment of 0.5, 1.0 and 1.5 mm. The ANOVA statistical analysis is consider finding the performance of the drill bits and the machining surface efficiently.

Analysis and optimization of circularity error in drilling Process using statistical technique

Drilling is a complex manufacturing process and its process parameter optimization enhances machining performance. Titanium alloy is extensively used in automobile and aerospace sectors because of its inherent properties. However, it is categorized into difficult to machine because of its properties. In this work, drilling process is carried out on titanium alloy with different machining conditions. Cutting conditions used are dry, wet and dry with cryogenically treated drill. Experiments are executed as per L9 orthogonal array. Statistical approaches such as orthogonal array and Analysis of Variance (ANOVA) are used to find the importance and effects of machining parameters. Process parameters are optimized and the effect of significance is estimated. Input parameters include feed, cutting speed and depth of cut. Output parameter includes circularity error. The result suggests that cryogenically treated carbide tool exhibits better machining performance than the dry and wet of non-treated tool and enhance sustainability in manufacturing.

ESSENCE OF THE TAGUCHI AND GRA METHOD IN OPTIMIZATION OF CUTTING PARAMETERS: A REVIEW

Nowadays, there is a drastic competition in manufacturing industries to provide the finest quality to the consumers with minimized production cost. Various processes are used for machining of different materials accordingly. But there are some major challenges which arise in machining of various alloys like poor surface finish, circularity error, burr formation etc. Different producers are adapting different techniques to optimize these features. This paper reviews different techniques used by researchers but it is observed that the taguchi with grey relational analysis is extensively used.

Experimental investigation on surface roughness and circularity error during drilling of polymer nanocomposites

In recent years, the researcher working in material science targeted composites due to the ability to tailor properties according to end application. The polymer nanocomposites are novel engineering polymer composites material with nano-scale reinforcement. The Nano carbon reinforced epoxy nanocomposites are widely used for the development of the product for medical and engineering applications. The machining characteristic is quite different from the machining of conventional material. During the machining of polymer composites, various types of defects associated with the machined component. The adequate and depth knowledge and understanding of the machining behavior is indeed necessary to identify the most favorable machining environments. In this paper, a drilling experiment was performed, and an investigation has been made under machining constrain for surface roughness and circularity error. The surface roughness and circularity error play a significant role in deciding the machined components' quality and performance. The ANOVA analysis has been performed to evaluate the drilling parameter’s significance on surface roughness and circularity error. For the drilling experiment, three different kinds of Tool Materials, i.e., HSS, Carbide, and TiAlN is used and experimentally examine their performance on the surface roughness and circularity error. The machining behavior of polymer composites largely depends on the nature of support, the amount of reinforcement within the matrix, and matrix material behavior.

Sustainable machining: Modelling and optimization using Taguchi, MOORA and DEAR methods

Sustainable machining of metallic parts offers significant economic, environmental and societal benefits to metal cutting industries. Although dry machining technology bring sustainability in machining industries but requires significant attention to get high productivity without affecting the geometrical accuracy and surface finish. The present work proposed a unified framework to model and optimize the process, when applied to sustainability. A CNC machine is used to turn the mild steel parts with the help of carbide inserts (TNMG 160408CQ). Taguchi L27 orthogonal array is used to model the turning process and analyze the factors (cutting speed, depth of cut and feed rate) on material removal rate, MRR, surface roughness, SR and circularity error, CE. Further, attempts are made to optimize the sustainability index taken into account of economic (higher MRR), social (desired lower SR and CE) and environmental (dry machining) aspects. To attain the said goal two popular optimization models (data envelopment analysis ranking, DEAR and multi-objective optimization on the basis of ratio analysis, MOORA) are considered. The said models are compared among themselves and proposed a single optimal condition for the turning process.

An Experimental Comparative Analysis of Twist Drilling, Helical Milling and Pilot Hole Machining for Large Diameters in CFRPs

Carbon fiber-reinforced polymer (CFRP) large diameter hole drilling is certifiably not a broadly examined theme on account of their non-homogeneity and anisotropic highlights. In the scope of aerospace industrial uses of this material, thousands of holes have to be machined for purposes of assembly. The quality of this machined hole is influenced adversely by matrix grid cratering, thermal damage, spalling, surface delamination, and material debasement or fiber pullout. Among these different deformities, delamination is considered the most severe for CFRP composite. The main objective of this work is to compare twist drilling, helical milling and pilot hole machining technologies concerning unidirectional CFRP composite. In addition, the force modules were also discussed. In the scope of this work, numerous machining experiments were conducted in unidirectional CFRP composite: herein the impact of the type of cutting tool and of process parameters on the quality of machined holes are analysed and discussed (diameter of holes, circularity error and characteristics of uncut fibres). In other to achieve a better hole quality, the Scanning electron microscope (SEM) analysis and evaluation of acquired data were conducted. Experimental results show holes machined using twist drilling method present the lowest-quality, with damages present at the tool entry and exit as compared to the other studied methods. This study intended to help in assisting technicians working on assembly large structural parts in aircraft or automobile industries in choosing the best hole machining procedure when this three are in consideration.

Effect of abandonment of cooling and lubrication on surface roughness and cylindricity in turning of steel

One of the defining global issues today is to reduce the load on the environment. Thus, in this paper, the effect, and consequences of the abandonment of cooling and lubrication were investigated when turning of non-alloyed steel. The 2D and 3D surface roughness parameters, cylindricity deviations and circularity errors were examined at different feeds and cutting speeds. The experiments were performed, using the full factorial experimental design method. It was found that with dry machining, the average roughness is slightly higher with increasing productivity, however, at lower feed and cutting speeds, the surface has better wear resistance and lubricant retention, and cylindricity deviation can be minimized.

Ultrazvukom potpomognuto bušenje laminatnog kompozita sa matricom od aluminijuma 2024 ojačanom SiC nanočesticama

Aluminum metal matrix composites are widely used in various engineering areas due to their excellent mechanical properties. However, due to their heterogeneous structure, efficient machining of these materials is still a challenging task. Therefore, in the present study the drilling performance of aluminium-copper alloy (Al 2024) reinforced with SiC nanoparticles was experimentally investigated, in the presence of ultrasonic vibration.In this regard, the influence of ultrasonic vibration, SiC weight fraction and drilling parameters was assessed on circularity error and drilling thrust force. Also, the optimization of process parameters was investigated using grey relational analysis. The performed calculations revealed that ultrasonic vibration, SiC content of 2 %wt, feed rate of 20 mm/min and spindle speed of 1400 rpm is the optimal parameters setting in the present study.

Parametric studies on SiC-abrasive jet assisted machining of alumina ceramics

Abstract Present study investigates machinability of K-90 alumina ceramic for Fluidized-Bed Abrasive Jet Machining (FB-AJM) in presence of Silicon Carbide (SiC) abrasives. Four input process factors such as pressure, standoff distance, abrasive temperature, and abrasive mesh size are considered associated with L16 orthogonal array design of experiment. Effects of AJM parameters on output responses viz. Material Removal Rate (MRR), Overcut (OC), and circularity error (deviation) are studied. In addition, Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) integrated with Taguchi method is applied to determine the most appropriate setting of AJM parameters in purview of maximum MRR, minimal OC, and minimal circularity error.

Eksperimentalno proučavanje kvaliteta rupe i različitih pristupa delaminaciji kod bušenja novog CARALL FML kompozita

In this study, the hole quality was investigated in the drilling of CARALL composite. In addition, the delamination factor calculation approaches of Chen, Davim, and Machado were compared in terms of the delamination damage at the hole entrance surface. Chen's approach is based on the conventional delamination factor (F d) and Davim's on the adjusted delamination factor (F da). Finally, Machado's approach is based on the minimum delamination factor (F min). The values closest to the nominal hole diameter value were obtained with the uncoated (T1), followed by the TiN-TiAlN-coated (T2) and TiAl/TiAlSiMoCr-coated (T3) carbide drills, respectively. The average circularity error values for the hole top and bottom surfaces were 6.184 µm, 7.647 µm, and 8.959 µm for T1, T2, and T3 tools, respectively. Delamination factor values varied between 1.174 and 1.804. The F da values were found to be the highest, followed by F d values, with F dmin values determined as the lowest.

Reducing circularity error by optimizing the Operating parameters in Fused deposition modeling using Genetic Algorithm

The Additive manufacturing of materials is growing rapidly in the area of research and development. Since it neglects the cost to make molds, jigs or fixtures for newly developed component which may be tested later. This work focuses on building parts using Fused Deposition Modelling (FDM) by producing optimum strength of materials. The property of the manufactured parts varies with change in process parameters. This limits the strength of the component manufactured using FDM which rely on controllable variables like raster width, bead width, contours, air gap, part orientation, rate of deposition, extrusion speed and printing speed. Deciding the optimum combination of all these parameters are difficult while making a product. This project focuses on an investigation on find an optimum level of part orientation, layer thickness and air gap for maximizing tensile strength and reducing the circularity error on manufactured part.

Experimental study on Titanium diamond by fabricating micro-holes using Micro-EDM with Taguchi’s method and response surface method

Titanium alloys are very hard to machine materials, which can be machined effectively by using advanced manufacturing processes. Electro discharge machining (EDM) process is one of the most efficient methods of machining electrically conductive materials. EDM is focused more on the precision and accuracy of the machined parts. This particular work focuses on the machinability study of titanium diamond using micro-EDM. Input parameters such as voltage, capacitance, feed rate and tool rotation speed (TRS) are varied and their effects are analyzed by evaluating responses such as material removal rate (MRR), machining time (MT), overcut (OC) and circularity error (CE). X-ray diffraction (XRD) analysis of the material is also conducted to observe the material phases and elements. The observed responses are simultaneously optimized by formulating overall evaluation criteria (OEC) for generating the optimal value of process parameters. Further, the analysis of variance (ANOVA) provides the influence of input parameters on each output response. The variation of different response measures with respect to input parameters is shown through 3D response surface plots. It is observed in micro EDM that the MT decreases with the increase in voltage, capacitance, feed rate and TRS, whereas MRR and OC increase with an increase in voltage and capacitance. In the case of CE, it decreases with the increase in voltage and it increases with the increase in capacitance.