Evaluation of CFRP Hole Quality in Low Frequency Vibration-Assisted Dry Drilling of CFRP/Ti Stacks

2018 ◽  
Author(s):  
Haojun Yang ◽  
Yan Chen ◽  
Jiuhua Xu
Keyword(s):  
Feed Rate ◽  
Kinematic Model ◽  
Mechanical Damage ◽  
Low Frequency ◽  
Spindle Speed ◽  
Hole Quality ◽  
Drilling Force ◽  
Low Frequency Vibration ◽  
The Impact ◽  
Conventional Drilling

Low frequency vibration assisted drilling (LFVAD) is regarded as one of the most promising process in CFRP/Ti stacks drilling. This work carries the investigation of the difference between conventional drilling and LFVAD based on kinematic model. The experiments are conducted under varied vibration amplitude to a specific feed rate, also under varying spindle speeds, feed rates when the ratio of amplitude to feed rate is fixed. Then the hole quality of CFRP is evaluated based on the analysis of drilling force, chip morphology, chip extraction. The results show that there is rarely no difference between conventional drilling and LFVAD in drilling mechanism when the drilling diameter is over 1 mm. Because the impact effect caused by drill vibration is already weak. It is found that the severe mechanical damage of the CFRP holes surface could be significantly reduced due to the fragmented chips obtained in vibration drilling. The maximum instantaneous feed rate combined with feed rate and amplitude plays a significant role in CFRP hole quality. Lower maximum instantaneous feed rate results in better hole wall quality and less entry delamination. Spindle speed has no visible influence on entry delamination, while higher spindle speed improves the hole surface quality due to the resin coating phenomenon.

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

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 891
Author(s):  
Numan Habib ◽  
Aamer Sharif ◽  
Aqib Hussain ◽  
Muhammad Aamir ◽  
Khaled Giasin ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Feed Rate ◽  
High Speed Steel ◽  
Spindle Speed ◽  
Drilling Process ◽  
Hole Size ◽  
Hole Quality ◽  
Dry Drilling ◽  
Drilling Parameters ◽  
The Impact

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).

scholarly journals Experimental Investigation, Modeling and Optimization of Circularity, Cylindricity and Surface Roughness in Drilling of PMMA Using ANN and ANOVA

2020 ◽  
Vol 57 (1) ◽  
pp. 57-68 ◽  
Author(s):  
Florin Susac ◽  
Felicia Stan
Keyword(s):  
Surface Roughness ◽  
Experimental Investigation ◽  
Feed Rate ◽  
Quality Characteristics ◽  
Spindle Speed ◽  
Hole Quality ◽  
Modeling And Optimization ◽  
Taguchi Design Of Experiments ◽  
The Impact ◽  
Cylindricity Error

In this paper, experimental investigation, modeling and optimization of the drilling of PMMA are performed using the Taguchi Design of Experiments (DOE), analysis of variance (ANOVA) and artificial neural networks (ANN) methods. Drilling experiments were conducted on PMMA to assess the impact of process parameters (drill diameter, spindle speed, and feed rate) on the hole-quality characteristics (surface roughness, circularity error, and cylindricity error). ANOVA was performed to identify the drilling parameters that have a statistically significant influence on the hole-quality characteristics. A predictive model for the hole-quality characteristics was derived using a four-layer ANN with a backpropagation algorithm and a sigmoidal transfer function at the hidden layers. The ANN model was able to accurately predict the hole-quality parameters with the absolute mean relative errors of the testing data in the limits of 3 to 7%. Based on the experimental results and analytical modeling, it was found that drilling of PMMA requires lower spindle speed and high feed rate when the integrity of the drill hole is the main quality criterion.

scholarly journals Comparative Analysis of Cutting Forces, Torques, and Vibration in Drilling of Bovine, Porcine, and Artificial Femur Bone with Considerations for Robot Effector Stiffness

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Oluseyi Adewale Orelaja ◽  
Xingsong Wang ◽  
Donghua Shen ◽  
Dauda Sh. Ibrahim ◽  
Tianzheng Zhao ◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Cutting Forces ◽  
Spindle Speed ◽  
Depth Of Cut ◽  
Drilling Process ◽  
Robot Arm ◽  
Drilling Force ◽  
Significant Drop ◽  
Negative Effect ◽  
Conventional Drilling

Bone drilling is known as one of the most sensitive milling processes in biomedical engineering field. Fracture behavior of this cortical bone during drilling has attracted the attention of many researchers; however, there are still impending concerns such as necrosis, tool breakage, and microcracks due to high cutting forces, torques, and high vibration while drilling. This paper presents a comparative analysis of the cutting forces, torques, and vibration resulted on different bone samples (bovine, porcine, and artificial femur) using a 6dof Robot arm effector with considerations of its stiffness effects. Experiments were conducted on two spindle speeds of 1000 and 1500 rpm with a drill bit diameter of 2.5 mm and 6 mm depth of cut. The results obtained from the specimens were processed and analyzed using MATLAB R2015b and Visio 2000 software; these results were then compared with a prior test using manual and conventional drilling methods. The results obtained show that there is a significant drop in the average values of maximum drilling force for all the bone specimens when the spindle speed changes from 1000 rev/min to 1500 rev/min, with a drop from (20.07 to 12.34 N), approximately 23.85% for bovine, (11.25 to 8.14 N) with 16.03% for porcine, and (5.62 to 3.86 N) with 33.99% for artificial femur. The maximum average values of torque also decrease from 41.2 to 24.2 N·mm (bovine), 37.0 to 21.6 N·mm (porcine), and 13.6 to 6.7 N·mm (artificial femur), respectively. At an increase in the spindle speed, the vibration amplitude on all the bone samples also increases considerably. The variation in drilling force, torque, and vibration in our result also confirm that the stiffness of the robot effector joint has negative effect on the bone precision during drilling process.

scholarly journals Enhancement of surface roughness for brittle material during rotary ultrasonic machining

2018 ◽  
Vol 249 ◽  
pp. 01006 ◽  
Author(s):  
Ankit Sharma ◽  
Atul Babbar ◽  
Vivek Jain ◽  
Dheeraj Gupta
Keyword(s):  
Surface Roughness ◽  
Feed Rate ◽  
Vibration Amplitude ◽  
Research Study ◽  
Float Glass ◽  
Spindle Speed ◽  
Ultrasonic Machining ◽  
Rotary Ultrasonic Machining ◽  
Hole Quality ◽  
The Core

Surface roughness is the key aspect which could increase the application of float glass by enhancing the machined hole quality. Glass is extensively used in microfluidic devices, bio-medical parts and biosensors. The core objective of the research study is to optimize the best parametric combination to achieve the least amount of surface roughness. The three major parameters which are used for designed experimental study are spindle speed, ultrasonic amplitude and feed rate. The least value of surface roughness is noticed at spindle speed (5000 rpm), vibration amplitude (20 μ m) and feed rate (6 mm/min) which be adopted for increasing its functional application. Consequently, after optimizing the parameters, least value of surface roughness at hole internal region is revealed as 1.09 μm.

Drilling Force and Chip Morphology in Drilling of PCB Supported Hole

2011 ◽  
Vol 188 ◽  
pp. 429-434 ◽  
Author(s):  
L.P. Yang ◽  
Li Xin Huang ◽  
Cheng Yong Wang ◽  
L.J. Zheng ◽  
Ping Ma ◽  
...  
Keyword(s):  
Feed Rate ◽  
Printed Circuit Board ◽  
Thrust Force ◽  
Chip Morphology ◽  
Cutting Parameters ◽  
Spindle Speed ◽  
Circuit Board ◽  
Drilling Process ◽  
Drilling Force ◽  
Drill Bits

Supported holes of Printed circuit board (PCB) are drilled with two different drill bits. Drilling force (thrust force and torque) and chip morphology are examined at different cutting parameters, and the effects of the two drills are discussed. The results indicate that the drilling force and chip morphology are affected by the feed rate, spindle speed and drill shape. Thrust force increases with the increasing feed rate, and decreases with the increasing spindle speed. Optimization of drill geometry can reduce the thrust force significantly, and is effective in chip breaking which can improve the chip evacuation during the drilling process.

Experimental Study of Ultrasonic Vibration Drilling Ceramic Material

2012 ◽  
Vol 217-219 ◽  
pp. 1863-1868 ◽  
Author(s):  
Ke Rang Zou ◽  
Chao Wang ◽  
Liao Yuan Zhang
Keyword(s):  
Ceramic Material ◽  
Ultrasonic Vibration ◽  
Diamond Tool ◽  
Superposition Principle ◽  
Kinematic Model ◽  
Drilling Force ◽  
Processing Efficiency ◽  
Vibration Drilling ◽  
The Impact

Abstract According to the high frequency vibration of the diamond tool and feed motion of the machine tool, the kinematic model of ultrasonic vibration machining was established by superposition principle. Its motion law was analyzed in theory. The experiments on the drilling force, the impact of load on the processing efficiency, and the surface quality of the workpiece with ultrasonic vibration drilling and traditional machining were carried out on the improved ultrasonic vibration drilling machine by way of drilling the ceramic material.

Study on hole machining for the constant feed rate of Al2O3 engineering ceramics through low-frequency axial vibration

2019 ◽  
Vol 234 (6-7) ◽  
pp. 971-979
Author(s):  
Lei Zheng ◽  
Chen Zhang ◽  
Xianglong Dong ◽  
Yong Feng ◽  
Wendong Wei ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Feed Rate ◽  
Low Frequency ◽  
Wall Surface ◽  
Axial Vibration ◽  
Drilling Force ◽  
Edge Chipping ◽  
Engineering Ceramics ◽  
Hole Machining ◽  
Constant Feed Rate

Engineering ceramics are increasingly extensively applied in the aerospace, vehicle, armor protection and other fields due to their excellent performances such as high compression strength, high hardness, low density and high protection performance. However, engineering ceramics are typical difficult-to-machine materials, especially in the hole machining under constant feed rate, which limits the promotion and application. In this study, by combining a specially developed novel thin-wall diamond trepanning bit with a low-frequency axial vibration machining, the hole machining process for the constant feed rate of Al2O3 engineering ceramics was experimentally studied and the influence of the low-frequency axial vibration process on the axial drilling force, hole-wall surface roughness and edge chipping size of holes machined was analyzed. The results showed that the low-frequency axial vibration machining obtained a lower axial drilling force and a smaller edge chipping size compared to the traditional drilling process. Moreover, both the axial drilling force and the edge chipping size declined markedly with the rise in amplitude. However, the hole-wall surface roughness presented a rising trend due to the hammering effect of vibration. The process technology proposed in this article realizes the hole machining for a constant feed rate of Al2O3 engineering ceramics and provides a reference for the engineering lot-size hole machining of engineering ceramics.

Study on Looseness and Impact - Rub Coupling Faults of a Vertical Dual-Disk Cantilever Rotor- Bearing System

2007 ◽  
Vol 353-358 ◽  
pp. 2479-2482
Author(s):  
Yan Jun Lu ◽  
Zhao Hui Ren ◽  
Hong Chen ◽  
Nai Hui Song ◽  
Bang Chun Wen
Keyword(s):  
Finite Element ◽  
Low Frequency ◽  
Element Model ◽  
Coupling Faults ◽  
Mechanics Model ◽  
Low Frequency Vibration ◽  
Rotor Bearing ◽  
Impact And Rubbing ◽  
The Impact ◽  
Bearing System

Because of wrong setting or long-term running of rotating machinery, the looseness may ouur in the bearing seats or bases. And also bring impact and rubbing of rotor-stator, That is the looseness and rub-impact coupling fault. In the paper,a mechanics model and a finite element model of a vertical dual-disk cantilever rotor- bearing system with coupling faults of looseness and rub-impact are set up. Based on the nonlinear finite element method and contact theory, the dynamical characteristices of the system under the influence of the looseness rigidity and impact-rub clearance is studied. The results show that the impact-rub of rotor-stator can reduce the low frequency vibration caused by looseness, and the impact-rub caused by looseness has obvious orientation. Also, the conclusion of diagnosing the looseness and rub-impact coupling faults is given in the end of the paper.

Experimental Investigation on Drilling Force and Hole Quality when Drilling of T800S/250F CFRP Laminate

2013 ◽  
Vol 797 ◽  
pp. 155-160 ◽  
Author(s):  
Qing Long An ◽  
Jin Yang Xu ◽  
Xiao Jiang Cai ◽  
Ming Chen
Keyword(s):  
High Strength ◽  
Spindle Speed ◽  
Machining Process ◽  
Twist Drill ◽  
Commercial Aircraft ◽  
Hole Quality ◽  
Drilling Force ◽  
Cfrp Laminate ◽  
Cfrp Laminates ◽  
Drilling Performance

High-strength carbon fiber reinforced plastic (CFRP) T800S/250F is used as the large commercial aircraft material for manufacturing the main load-bearing structural components. Drilling is the mostly used in final machining process of CFRP laminates, while the delamination and burrs occur frequently at the drill exit in the CFRP laminate. In this paper, the machinability of T800S/250F was investigated in term of drilling force and hole quality by using a twist drill and a dagger drill. The experimental results indicated that high spindle speed and low feed rate favor the reduction of thrust force for both drill bits. High spindle speed is a preference to gain the good hole quality at drill exit especially for the dagger drill, which also shows excellent drilling performance than the twist drill and was more suitable for drilling of T800S/250F CFRP laminate.

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