Effects of Feedrate and Chisel Edge on Delamination in Composites Drilling

1993 ◽  
Vol 115 (4) ◽  
pp. 398-405 ◽  
Author(s):  
S. Jain ◽  
D. C. H. Yang
Keyword(s):  
Composite Laminates ◽  
Thrust Force ◽  
Plate Theory ◽  
Tool Geometry ◽  
Laminated Plate ◽  
Elliptical Plate ◽  
Time Optimal ◽  
Critical Thrust Force ◽  
Clamped Edges ◽  
Central Load

Delamination accompanied with the drilling of composite laminates has been recognized as a major problem. An analytical model is established to predict critical thrust force and critical feedrate at which the delamination crack begins to propagate. For unidirectional composites, the delamination zone is modeled as an elliptical plate, with clamped edges and subjected to a central load. Based on fracture mechanics, laminated plate theory and cutting mechanics, expressions are developed for critical thrusts and critical feedrates at which delamination is initiated at different ply locations. This model has been verified by experiments. A variable feedrate strategy is formulated based on this model, which avoids delamination while drilling in a time-optimal fashion. In addition, the need to modify tool geometry to avoid delamination is highlighted. Chisel edge width has been identified as an important factor contributing to the thrust force and hence delamination.

Delamination-Free Drilling of Composite Laminates

1994 ◽  
Vol 116 (4) ◽  
pp. 475-481 ◽  
Author(s):  
S. Jain ◽  
D. C. H. Yang
Keyword(s):  
Composite Laminates ◽  
Thrust Force ◽  
Tool Geometry ◽  
Elliptical Plate ◽  
Hole Quality ◽  
Drilling Operation ◽  
Twist Drills ◽  
Drill Tool

Composite laminates in significant numbers are rendered unacceptable due to delamination that occurs during the drilling operation. Thrust generated during the drilling operation is identified as responsible for delamination. Expressions developed for critical thrusts and critical feed rates, by modeling the delamination zone as an elliptical plate in unidirectional laminates, appear to be fairly accurate. It has been demonstrated that the critical thrusts and feed rates obtained for unidirectional laminates can be conservatively used for multi-directional laminates. With regard to the tool geometry, the chisel edge width appears to be the single most important factor contributing to the thrust force and hence delamination. A diamond-impregnated tubular drill tool was designed and tested. This tool resulted in a much smaller thrust and much better hole quality as compared with the standard twist drills.

Optimal control during drilling in GFRP composite laminates

2014 ◽  
Vol 10 (4) ◽  
pp. 611-630 ◽  
Author(s):  
Amrinder Pal Singh ◽  
Manu Sharma ◽  
Inderdeep Singh
Keyword(s):  
Optimal Control ◽  
State Space ◽  
Feed Rate ◽  
Composite Laminates ◽  
Transfer Functions ◽  
Thrust Force ◽  
Optimal Controller ◽  
Content Type ◽  
Force Profile ◽  
Critical Thrust Force

Purpose – Damage due to delamination is an important issue during drilling in polymer-matrix composites (PMCs). It depends on thrust force and torque which are functions of feed rate. Transfer function of thrust force with feed rate and torque with feed rate is constructed through experiments. These transfer functions are then combined in state-space to formulate a sixth-order model. Then thrust force and torque are controlled by using optimal controller. The paper aims to discuss these issues. Design/methodology/approach – A glass fiber reinforced plastic composite is drilled at constant feed rate during experimentation. The corresponding time response of thrust force and torque is recorded. Third-order transfer functions of thrust force with feed rate and torque with feed rate are identified using system identification toolbox of Matlab®. These transfer functions are then converted into sixth-order combined state-space model. Optimal controller is then designed to track given reference trajectories of thrust force/torque during drilling in composite laminate. Findings – Optimal control is used to simultaneously control thrust force as well as torque during drilling. There is a critical thrust force during drilling below which no delamination occurs. Therefore, critical thrust force profile is used as reference for delamination free drilling. Present controller precisely tracks the critical thrust force profile. Using critical thrust force as reference, high-speed drilling can be done. The controller is capable of precisely tracking arbitrary thrust force and torque profile simultaneously. Findings suggest that the control mechanism is efficient and can be effective in minimizing drilling induced damage in composite laminates. Originality/value – Simultaneous optimal control of thrust force and torque during drilling in composites is not available in literature. Feed rate corresponding to critical thrust force trajectory which can prevent delamination at fast speed also not available has been presented.

Prediction of critical thrust force for exit-ply delamination during drilling composite laminates: thermo-mechanical analysis

2016 ◽  
Vol 18 (1/2) ◽  
pp. 77 ◽  
Author(s):  
Jamel Saoudi ◽  
Redouane Zitoune ◽  
Suhasini Gururaja ◽  
Salah Mezlini ◽  
Akshay Amaranath Hajjaji
Keyword(s):  
Composite Laminates ◽  
Thrust Force ◽  
Mechanical Analysis ◽  
Critical Thrust Force

scholarly journals The effect of thrust force in drilling composite materials using step core-ball drill

2018 ◽  
Vol 185 ◽  
pp. 00016
Author(s):  
Hsing-Ming Teng ◽  
Chung-Chen Tsao
Keyword(s):  
Composite Materials ◽  
Composite Laminates ◽  
Thrust Force ◽  
Weight Ratio ◽  
Composite Plates ◽  
High Strength ◽  
Tool Geometry ◽  
Machining Parameters ◽  
Chip Flow ◽  
Hole Making

Composite materials have gained increasing popularity over the past few decades due to their superior mechanical properties, such as high strength-to-weight ratio, fighting against high temperature and corrosion resistance. The assembly of enormous aeronautical components and structures require the machining of composite materials. Drilling is the most important hole-making process in the final assembly. When drilling composite materials, a number of defects are generating. Delamination caused by drilling thrust has been showed as one of the most problematic defects after drilling composite laminates. With a pressing need for decreased delamination, many studies are turning more and more toward tool geometry and machining parameters. Drilling of composite plates using a step core-ball drill, which is a special drill to improve the chip flow and reduces the thrust force at the exit of hole, is investigated in this study. The experimental results found that the step core-ball drill was efficient in drilling of carbon fiber reinforced plastic (CFRP) and did not produce loading on the drill exit at the proper drilling conditions. The results obtained from this study feeding back for fundamental research efforts could steer future studies on the drilling composite materials in the most promising direction.

The Effect of Thrust Force in Drilling Composite Materials Using a New Step Core-Ball Drill

2020 ◽  
Vol 830 ◽  
pp. 77-84
Author(s):  
Hsing Ming Teng ◽  
Ming Chang Wu ◽  
Jin Yi Kao ◽  
Chun Yao Hsu ◽  
Chung Chen Tsao
Keyword(s):  
Composite Materials ◽  
Composite Laminates ◽  
Thrust Force ◽  
Composite Plates ◽  
High Strength ◽  
Tool Geometry ◽  
Lower Weight ◽  
Final Assembly ◽  
Chip Flow ◽  
Metal Materials

Compared with conventional metal materials, composite materials can sustain more loads under lower weight and lower space, which is more suitable to use in high strength environment for structure parts application in aerospace, military, transportation and leisure. The enormous aeronautical components and structures of composite materials require assembly and machining. Drilling is the most important making-hole process in the final assembly. However, conventional drill cannot avoid delamination in drilling composite materials effectively depending on tool geometry only. Delamination caused by drilling thrust has been showed as one of the most problematic defects after drilling composite laminates. Drilling of composite plates using a new step core-ball drill (NSCBD), which is a special drill to improve the chip flow and reduces the thrust force (delamination) at the exit of hole, is studied and compared to the traditional step core-ball drill (TSCBD). The thrust force of new step core-ball drill in drilling composite materials was investigated in this study. The theoretical analysis and experimental results show that the NSCBD can improve the thrust force (delamination) and efficiency than TSCBD in drilling composite materials.

Mechanics of delamination-free drilling in polymer matrix composite laminates: A review

2020 ◽  
pp. 095440622093482
Author(s):  
Anurag Thakur ◽  
Amrinder Pal Singh ◽  
Manu Sharma
Keyword(s):  
Polymer Matrix ◽  
Composite Laminates ◽  
Thrust Force ◽  
Point Load ◽  
Machining Parameters ◽  
Isotropic Composite ◽  
Distributed Load ◽  
Anisotropic Composite ◽  
Uniformly Distributed Load ◽  
Critical Thrust Force

There is a critical limit of thrust force during drilling operation in a composite laminate below which no delamination takes place, which is known as the “critical thrust force”. In this paper, various critical thrust force models have been discussed in detail for circular- and elliptical-shaped delaminations around the drilled hole. Critical thrust force models for circular-shaped delamination for isotropic composite laminates and anisotropic composite laminates for different loadings like point load, uniformly distributed load, triangular load, and their combinations using different drill geometries have been discussed. With elliptical-shaped delamination, critical thrust force models for anisotropic composite laminates are discussed for: point load, uniformly distributed load, combined point plus distributed load, and point load for antisymmetric composite laminates. At several locations, graphs have been created to illustrate the dependence of various parameters on the critical thrust force. These graphs will be of use for practising engineers while selecting tool or/and machining parameters during drilling of polymer matrix composites. A tool designer can get good insight from these graphs while designing an optimal drilling tool. The paper highlights the importance of load distribution across the drill causing deflection leading to damage due to delamination in composite laminates. Special drill geometries help in better distribution of thrust forces towards periphery and improve the critical thrust force for the prevention of damage due to delamination during drilling in composite laminates.

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

Metals ◽  
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.

Nonlinear Oscillations of a Composite Laminated Plate with Parametrically and Externally Excitations

2013 ◽  
Vol 699 ◽  
pp. 641-644
Author(s):  
Xiao Li Bian ◽  
Shuang Bao Li
Keyword(s):  
Thin Plate ◽  
Nonlinear Oscillations ◽  
Plate Theory ◽  
Laminated Plate ◽  
Rectangular Thin Plate ◽  
Third Order ◽  
Composite Laminated Plate ◽  
Strain Relationship ◽  
Relationship Of ◽  
Equations Of Motions

Nonlinear oscillations of a simply-supported symmetric cross-ply composite laminated rectangular thin plate are investigated in this paper. The rectangular thin plate is subjected to the transversal and in-plane excitations. Based on the Reddy’s third-order shear deformation plate theory and the stress-strain relationship of the composite laminated plate, a two-degree-of-freedom non-autonomous nonlinear system governing equations of motions for the composite laminated rectangular thin plate is derived by using the Galerkin’s method. Numerical simulations illustrate that there exist complex nonlinear oscillations for composite laminated rectangular thin plate.

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