EVALUATION OF THE EFFECTS OF DRILLING PARAMETERS, TOOL GEOMETRY AND CORE MATERIAL THICKNESS ON THRUST FORCE AND DELAMINATION IN THE DRILLING OF SANDWICH COMPOSITES

This study examined the effects of drilling parameters, tool geometry, and core material thickness (CMT) on thrust force and the delamination factor in the drilling of sandwich composites. Aluminum honeycomb (10 and 15[Formula: see text]mm in thickness) was used as the core material, with carbon fiber-reinforced polymer (CFRP) as the top and bottom surfaces. In the drilling experiments, three different cutting speeds (60, 78 and 100[Formula: see text]m/min) and two different feed rates (0.05 and 0.075[Formula: see text]mm/rev) were used. Drills having a diameter of 6.35[Formula: see text]mm and three different geometries (candlestick drills, twist drills and dagger drills) were used in the experiments. At the end of the experiments, thrust force was seen to increase with increased feed rate and CMT. Increased cutting speed generally decreased the thrust forces and the minimum thrust force was achieved with the 10 mm thick core material, 0.05[Formula: see text]mm/rev feed rate and 100[Formula: see text]m/min cutting speed using the dagger drill. The delamination factor at the entrance area was very low when drilling the sandwich composites and there was no significant difference based on drilling parameters, tool geometry, or CMT. Tool geometry was the main effective factor on exit delamination, and the highest delamination occurred with the use of the candlestick drill. Although increased feed rate increased delamination with all tools, with the dagger drill, increased cutting speed led to a severe increase. Delamination, tearing, and uncut fiber formation were observed when images of the exit areas of the drilled holes were examined.

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Evaluation of Factors Affecting Delamination, Tensile Strength, Thrust Force and Surface Roughness in Drilling of GFRP

10.21203/rs.3.rs-207947/v1 ◽

2021 ◽

Author(s):

Erol KILICKAP ◽

Yahya Hışman Celik ◽

Burak Yenigun

Keyword(s):

Surface Roughness ◽

Tensile Strength ◽

Feed Rate ◽

Thrust Force ◽

Cutting Temperature ◽

Cutting Speed ◽

Gfrp Composites ◽

Glass Fiber Reinforced Plastic ◽

Delamination Factor ◽

Drilling Parameters

Abstract The drilling operation of glass fiber reinforced plastic (GFRP) composites has gained importance because they are used as structural components in many industries such as aerospace and aviation. In the drilling of GFRP composites, some problems such as deformation and fiber breakage occur. Thrust force, delamination, surface quality and cutting temperature are affected by drilling parameters and woven types in the drilling of GFRP composites. At the same time, delamination also affects tensile strength. In this study, the effects of drilling parameters and woven types of GFRP composites on thrust force, surface roughness, delamination factor, and cutting temperature were examined in the drilling of GFRP composites produced in unidirectional (UD), ± 45º and 0°/90º woven types. The effects of drilling parameters and the delamination factor on the tensile strength of the drilled specimen were also investigated. The result of this study indicated that thrust force, delamination factor, and surface roughness increased with increasing cutting speed and feed rate. An increase in feed rate decreased the cutting temperature while an increase in cutting speed increased the cutting temperature. Also, it was found that the delamination had a critical influence on the tensile strength of the GFRP composites.

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EFFECT OF DRILLING PARAMETERS ON THRUST FORCE AND TORQUE DURING DRILLING OF ALUMINIUM 6061 ALLOY - BASED ON TAGUCHI DESIGN OF EXPERIMENTS

Journal of Mechanical Engineering ◽

10.3329/jme.v46i1.32522 ◽

2017 ◽

Vol 46 (1) ◽

pp. 41-48 ◽

Cited By ~ 8

Author(s):

Reddy Sreenivasulu ◽

Chalamalasetti Srinivasa Rao

Keyword(s):

Feed Rate ◽

Thrust Force ◽

Rectangular Cross Section ◽

Cutting Speed ◽

Tool Geometry ◽

Drill Bit ◽

Taguchi Design Of Experiments ◽

Drilling Parameters ◽

Signal Amplifier ◽

Twist Drills

Hole generating process with drill bit called as drilling, which is very important because large portion of overall machining of any component in production industry needs assemble of parts to make a final shape with rivets and fasteners. It is well known that the drill point geometry has a significant effect on thrust force exerted by a drill bit while drilling. In this study, experimentally investigate the influence of drilling parameters such as pointangle, clearance angle, cutting speed, feed rate and drill diameter on the thrust force and torque in drilling. Drilling experiments have been conducted over a wide a range of machining conditions such as cutting speed varied in the range 500 rpm to 1000 rpm in 3steps, feed rate varied from 0.3 to 0.6mm /min in three steps using two flutesuncoated conventional twist drills of three different diameters (8, 10 and 12mm) with 1180 point and 450 helix angles. Drill bits tool geometry altered by tool&cutter grinder and obtained 1100, 1000 point angles also clearance angles varied by 40, 60 and 80. Holes are performed on Aluminium 6061 alloy material of rectangular cross section having dimensions 300mmx50mmx10mm as per taguchi technique. A kistler (type 9272), four components drill tool dynamometer was used to measure thrust force (Th) and torque (M) exerted by the drill bit during hole making on a work material further the signal was processed to a computer by a multichannel signal amplifier (Kistler 5070 type) was used to record the thrust force and torque. Finally, ANOVA test have been carried out to confirm thesignificance of factors considered during drilling and compare the predicted values with the experimental values on influence of factors on responses.

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Defect evaluation of the honeycomb structures formed during the drilling process

International Journal of Damage Mechanics ◽

10.1177/1056789519860573 ◽

2019 ◽

Vol 29 (3) ◽

pp. 454-466

Author(s):

P Ghabezi ◽

M Farahani ◽

A Shahmirzaloo ◽

H Ghorbani ◽

NM Harrison

Keyword(s):

Feed Rate ◽

Cutting Speed ◽

Drilling Process ◽

Delamination Factor ◽

Drilling Parameters ◽

Principal Factors ◽

Novel Method ◽

Full Factorial Experimental Design ◽

Tool Diameter ◽

Full Factorial

In this paper, a comprehensive experimental investigation was carried out to precisely characterize the delamination and uncut fiber in the drilling process. A digital imaging procedure was developed in order to calculate the damage resulted from the drilling process. A novel method is proposed in this article based on image intensity to verify the obtained results. A full factorial experimental design was performed to evaluate the importance of the drilling parameters. Among other process parameters, feed rate, cutting speed, and tool diameter are the principal factors responsible for the delamination damage size during the drilling. The drilling process was assessed based on two proposed incurred damage factors, specifically the delamination factor and uncut fiber factor. Experimental results demonstrated that the feed rate was the paramount parameter for both delamination and uncut fiber factors. It was observed that both factors increased with an increase in the feed rate. Additionally, by increasing the tool diameter, the delamination and uncut fiber factors significantly increase. The effects of the cutting speed on damage factors were not linear. The minimum delamination factor and uncut fiber factor were obtained at the cutting speed of 1500 and 2500 r/min, respectively.

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Surface quality optimization of CFRP plates drilled with standard and step drill bits using TAGUCHI, TOPSIS and AHP method

Engineering Computations ◽

10.1108/ec-04-2020-0202 ◽

2020 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

Gökhan Sur ◽

Ömer Erkan

Keyword(s):

Surface Roughness ◽

Surface Quality ◽

Thrust Force ◽

Cutting Speed ◽

Cutting Parameters ◽

Tool Geometry ◽

Ahp Method ◽

Content Type ◽

Delamination Factor ◽

Drill Bits

Purpose Drilling of carbon fiber reinforced plastic (CFRP) composite plates with high surface quality are of great importance for assembly operations. The article aims to optimize the drill geometry and cutting parameters to improve the surface quality of CFRP composite material. In this study, CFRP plates were drilled with uncoated carbide drill bits with standard and step geometry. Thus, the effects of standard and step drill bits on surface quality have been examined comparatively. In addition, optimum output parameters were determined by Taguchi, ANOVA and multiple decision-making methods. Design/methodology/approach Drill bit point angles were selected as 90°, 110° and 130°. In cutting parameters, three different cutting speeds (25, 50 and 75 m/min) and three different feeds (0.1, 0.15 and 0.2 mm/rev) were determined. L18 orthogonal sequence was used with Taguchi experimental design. Three important output parameters affecting the surface quality are determined as thrust force, surface roughness and delamination factor. For each output parameter, the effects of drill geometry and cutting parameters were evaluated. Input parameters affecting output parameters were analyzed using the ANOVA method. Output parameters were estimated by creating regression equations. Weights were determined using the analytic hierarchy process (AHP) method, and multiple output parameters were optimized using technique for order preference by Similarity to An ideal solution (TOPSIS). Findings It has been determined from the experimental results that step drills generate smaller thrust forces than standard drills. However, it has been determined that it creates greater surface roughness and delamination factor. From the Taguchi analysis, the optimum input parameters for Fz step tool geometry, 90° point angle, 75 m/min cutting speed and 0.1 mm/rev feed. For Fd, are standard tool geometry, 90° point angle, 25 m/min cutting speed and 0.1 mm/rev feed and for Ra, are standard tool geometry, 130° point angle, 25 m/min cutting speed and 0.1 mm/rev feed. ANOVA analysis determined that the most important parameter on Fd is the tip angle, with 56.33%. The most important parameter on Ra and Fz was found to be 40.53% and 77.06% tool geometry, respectively. As a result of the optimization with multiple criteria decision-making methods, the test order that gave the best surface quality was found as 4–1-9–5-8–17-2–13-6–16-18–15-11–10-3–12-14. The results of the test number 4, which gives the best surface quality, namely, the thrust force is 91.86 N, the surface roughness is 0.75 µm and the delamination factor is 1.043. As a result of experiment number 14, which gave the worst surface quality, the thrust force was 149.88 N, the surface roughness was 3.03 µm and the delamination factor was 1.163. Practical implications Surface quality is an essential parameter in the drilling of CFRP plates. Cutting tool geometry comes first among the parameters affecting this. Therefore, different cutting tool geometries are preferred. A comparison of these cutting tools is discussed in detail. On the other hand, thrust force, delamination factor and surface roughness, which are the output parameters that determine the surface quality, have been optimized using the TOPSIS and AHP method. In this way, this situation, which seems complicated, is presented in a plain and understandable form. Originality/value In the experiments, cutting tools with different geometries are included. Comparatively, its effects on surface quality were examined. The hole damage mechanism affecting the surface quality is discussed in detail. The results were optimized by evaluating Taguchi, ANOVA, TOPSIS and AHP methods together.

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Optimization for drilling process of metal-composite aeronautical structures

Science and Engineering of Composite Materials ◽

10.1515/secm-2021-0027 ◽

2021 ◽

Vol 28 (1) ◽

pp. 264-275

Author(s):

Cristiano Devitte ◽

Gabriel S. C. Souza ◽

André J. Souza ◽

Volnei Tita

Keyword(s):

Feed Rate ◽

Composite Laminates ◽

Thrust Force ◽

Cutting Speed ◽

Statistical Design ◽

Burr Formation ◽

Drilling Process ◽

Metal Composite ◽

Aircraft Manufacturing ◽

Delamination Factor

Abstract 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 significant factor was the influence of the drill type (combined or not with feed rate). In fact, it was verified that the feed rate and the drill type were the most significant parameters on the delamination factor, while the feed rate was the most relevant on thrust force. The cutting speed did not affect significantly thrust force and delamination factor at exit ( F da S ) \hspace{.25em}({F}_{{\text{da}}_{\text{S}}}) . However, the combination f × v c was significant in delamination factor at entrance ( F da E ) \text{ }({F}_{{\text{da}}_{\text{E}}}) . Based on the optimized input parameters, they presented lower values for delamination factors ( F da E = 1.18 {F}_{{\text{da}}_{\text{E}}}=1.18 and F da S = 1.33 {F}_{{\text{da}}_{\text{S}}}=\hspace{.25em}1.33 ) and thrust force ( F t = 67.3 N {F}_{\text{t}}=67.3\hspace{.5em}\text{N} ). These values were obtained by drilling the metal-composite laminates with 85C-tool, 0.05 mm rev−1 feed rate, and 20 m min−1 cutting speed. However, the burrs at the hole output of AA2024 were considered unsatisfactory for this specific condition, which implies additional investigation.

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Effect of Cutting Environments on Drilling Induced Damage in GFRP Nanocomposites

Volume 2B: Advanced Manufacturing ◽

10.1115/imece2020-23302 ◽

2020 ◽

Author(s):

Panchagnula Kishore Kumar ◽

Panchagnula Jayaprakash Sharma

Keyword(s):

Feed Rate ◽

Thrust Force ◽

Cutting Speed ◽

Cutting Parameters ◽

Machining Process ◽

Glass Fiber Reinforced Plastic ◽

Delamination Factor ◽

Glass Fiber Reinforced ◽

Solid Carbide ◽

Torque Values

Abstract Drilling is most commonly used secondary machining process for structural joining of Glass Fiber Reinforced Plastic (GFRP) composites. Performing drilling operations on GFRPs/Multi-Walled CarbonNanoTubes (MWCNTs) reinforced GFRPs is really a challenging task due to their non-homogeneity and anisotropic behavior, which directs to generation of material damages. The prime focus of current work is to identify the suitable process parameters for enhancing the performance of drilling of GFRP nanocomposites. In this study, the drilling experiments are conducted on 0.3wt.% MWCNT-GFRP nanocomposites with solid carbide, TiCN and TiAlN coated drills (6mm diameter) under dry and chilled air cutting environments. The dry drilling experiments are conducted without any assistance of cooling fluid in ambient condition. The chilled air at a temperature of 3°C was supplied from the vortex tube. Experimental data is used for ANOVA (balanced) analysis. The cutting parameters such as feed rate, cutting speed and tool type (coating) are considered as input and the measured thrust force, delamination factor and AE RMS signal are treated as output responses. From ANOVA results, it is observed that the influence of feed rate is more on thrust force as compared to cutting speed. The coefficients of determination (R2) shows good fit between thrust force and cutting parameters and the corresponding confidence levels are above 98% for all cutting environments. Similarly, R2 values of delamination factor and AE RMS signals are above 90% and 96% respectively. The minimum thrust force and torque values are noted as 12.61 N and 0.152 N-m respectively at lower feed rate (10 mm/min) and higher cutting speed (1500 RPM) using TiCN coated drill under chilled air cutting environment. The delamination factor is also low (1.025) under the same cutting conditions of minimum cutting forces. A good correlation exists between the thrust force vs. delamination factor (> 0.85) and the delamination factor vs. AE RMS signal (> 0.80) for the selected cutting environments. The recommended range of RMS voltage is 0.083 to 0.121 volts for producing the delamination free holes on GFRP nanocomposites.

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Multi-objective optimization of process parameters for drilling fibermetal laminate using a hybrid GRA-PCA approach

FME Transaction ◽

10.5937/fme2102356e ◽

2021 ◽

Vol 49 (2) ◽

pp. 356-366

Author(s):

Ergün Ekici ◽

Ali Motorcu ◽

Gültekin Uzun

Keyword(s):

Feed Rate ◽

Thrust Force ◽

Cutting Speed ◽

Gray Relational Analysis ◽

Effective Control ◽

Multi Objective Optimization ◽

Multi Objective ◽

Control Factors ◽

Delamination Factor ◽

Tool Coating

This study investigated the effects of drilling parameters and cutting tool coating conditions on the thrust force, surface roughness, and delamination factor in the drilling of fiber-reinforced carbon reinforced aluminum laminate (CARALL) composite, a commercial type of fibermetal laminate. Gray relational analysis (GRA) was used as a multi-objective optimization method to determine optimum processing parameters and principal component analysis (PCA) was used to determine the weights. According to the findings of this experimental study, the most effective control factors for the thrust force, surface roughnes, and delamination factor were the feed rate, tool coating condition-cutting speed interaction, and tool coating condition, with 93.87%, 66.504%, and 29.137% contribution rates, respectively. From the results of the GRA-PCA analysis, the optimum levels of the control factors were determined as 110 m/min cutting speed, 0.1 mm/rev feed rate, and the uncoated tool.

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Machinability Analysis of Delamination and Thrust Force in Drilling of Pure and Added GFRP Composites

10.21203/rs.3.rs-217050/v1 ◽

2021 ◽

Author(s):

Ali Unuvar ◽

Osman Öztürk

Keyword(s):

Feed Rate ◽

Thrust Force ◽

Cutting Speed ◽

Cutting Parameters ◽

Cutting Conditions ◽

Machining Parameters ◽

Glass Fiber Reinforced ◽

Drilling Parameters ◽

Machinability Index ◽

Parametric Relationships

Abstract The aim of this work is to define the cutting conditions that allow the drilling of added glass fiber reinforced epoxy composite materials by taking into consideration the exit delamination factor, thrust force and the optimum combination of drilling parameters. The experiments were carried out under two cutting parameters such as cutting speed and feed rate for three levels each. Taguchi experimental design is used to reduce the excessive number of experiments. The experiment design was accomplished by application of the statistical analysis of variance (ANOVA). Correlations between cutting speed/feed rate and the various machining parameters were established to optimize cutting conditions. These correlations were found by quadratic regression using response surface methodology (RSM). Multiple regression analysis (MRA) was also employed to establish parametric relationships between the experimental parameters and the machinability outputs consisting of delamination and thrust force. The machinability refers to the relative ease or difficulty under certain cutting conditions. Therefore, it is very important to understand the factors affect the machinability and to evaluate their effects. Machinability of GFRP composites was enquired. It is aimed to evaluate the machinability of these materials. A machinability index has been developed in current study.

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Effect of Twist Drill Geometry and Drilling Parameters on Hole Quality in Single-Shot Drilling of CFRP/Al7075-T6 Composite Stack

Journal of Composites Science ◽

10.3390/jcs5070189 ◽

2021 ◽

Vol 5 (7) ◽

pp. 189

Author(s):

Muhammad Hafiz Hassan ◽

Jamaluddin Abdullah ◽

Gérald Franz ◽

Chim Yi Shen ◽

Reza Mahmoodian

Keyword(s):

Feed Rate ◽

Thrust Force ◽

Critical Dimension ◽

Helix Angle ◽

Single Shot ◽

Twist Drill ◽

Hole Quality ◽

Drilling Parameters ◽

Industry Practice ◽

Maximum Thrust

Drilling two different materials in a layer, or stack-up, is being practiced widely in the aerospace industry to minimize critical dimension mismatch and error in the subsequent assembly process, but the compatibility of the drill to compensate the widely differing properties of composite is still a major challenge to the industry. In this paper, the effect of customized twist drill geometry and drilling parameters are being investigated based on the thrust force signature generated during the drilling of CFRP/Al7075-T6. Based on ANOVA, it is found that the maximum thrust force for both CFRP and Al7075-T6 are highly dependent on the feed rate. Through the analysis of maximum thrust force, supported by hole diameter error, hole surface roughness, and chip formation, it is found that the optimum tool parameters selection includes a helix angle of 30°, primary clearance angle of 6°, point angle of 130°, chisel edge angle of 30°, speed of 2600 rev/min and feed rate of 0.05 mm/rev. The optimum parameters obtained in this study are benchmarked against existing industry practice of the capability to produce higher hole quality and efficiency, which is set at 2600 rev/min for speed and 0.1 mm/rev for feed rate.

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Effect of Cutting Parameters and Tool Geometry on the Performance Analysis of One-Shot Drilling Process of AA2024-T3

Metals ◽

10.3390/met11060854 ◽

2021 ◽

Vol 11 (6) ◽

pp. 854

Author(s):

Muhammad Aamir ◽

Khaled Giasin ◽

Majid Tolouei-Rad ◽

Israr Ud Din ◽

Muhammad Imran Hanif ◽

...

Keyword(s):

Feed Rate ◽

Surface Defects ◽

Thrust Force ◽

Cutting Tools ◽

Chip Thickness ◽

Cutting Parameters ◽

Spindle Speed ◽

Machining Process ◽

Tool Geometry ◽

Drilling Process

Drilling is an important machining process in various manufacturing industries. High-quality holes are possible with the proper selection of tools and cutting parameters. This study investigates the effect of spindle speed, feed rate, and drill diameter on the generated thrust force, the formation of chips, post-machining tool condition, and hole quality. The hole surface defects and the top and bottom edge conditions were also investigated using scan electron microscopy. The drilling tests were carried out on AA2024-T3 alloy under a dry drilling environment using 6 and 10 mm uncoated carbide tools. Analysis of Variance was employed to further evaluate the influence of the input parameters on the analysed outputs. The results show that the thrust force was highly influenced by feed rate and drill size. The high spindle speed resulted in higher surface roughness, while the increase in the feed rate produced more burrs around the edges of the holes. Additionally, the burrs formed at the exit side of holes were larger than those formed at the entry side. The high drill size resulted in greater chip thickness and an increased built-up edge on the cutting tools.

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