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 ◽  
...  

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).

2014 ◽  
Vol 66 (3) ◽  
Author(s):  
Mohd Amran ◽  
Siti Salmah ◽  
Mohd Sanusi ◽  
Mohd Yuhazri ◽  
Noraiham Mohamad ◽  
...  

This paper presents the effect of drilling parameters on surface roughness and surface appearance by applying response surface method (RSM). The mathematical model for correlating the interactions of drilling parameters such as spindle speed, feed rate and drill diameter on surface roughness was developed. RSM methodology was used as it is a technique that most practical and effective way to develop a mathematical model. In addition, this method also can reduce trial and error in experiment. Since the number of factors are three; spindle speed, feed rate and drill diameter, by applying RSM the total numbers of experiment involved are 20 experimental observations. From the experimental result, it is found that the minimum surface roughness on the hole was 1.06 mm from combination of 2000 rpm spindle speed, 78 mm/min feed rate and 2.5 mm drill diameter. While the maximum surface roughness 2.59 mm was the combination of 250 rpm spindle speed, 153 mm/min feed rate and 3.5 mm drill diameter. A mathematical equation was developed with percentage of error are 0% to 29%. Thus, from the result we understand that to find the smooth surface in drilling process, it needs higher spindle speed with lower feed rate and smaller diameter.


2020 ◽  
Vol 57 (1) ◽  
pp. 57-68 ◽  
Author(s):  
Florin Susac ◽  
Felicia Stan

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.


Author(s):  
Haojun Yang ◽  
Yan Chen ◽  
Jiuhua Xu

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.


2018 ◽  
Vol 249 ◽  
pp. 01006 ◽  
Author(s):  
Ankit Sharma ◽  
Atul Babbar ◽  
Vivek Jain ◽  
Dheeraj Gupta

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.


2015 ◽  
Vol 1119 ◽  
pp. 622-627 ◽  
Author(s):  
Chye Lih Tan ◽  
Azwan Iskandar Azmi ◽  
Noorhafiza Muhammad

Drilling is an essential secondary process for near net-shape of hybrid composite as to achieve the required dimensional tolerances prior to final application. Dimensional tolerance is often influenced by the surface integrity or surface roughness of the workpart. Thus, this paper aims to employ the Taguchi and response surface methodologies in minimizing the surface roughness of drilled carbon-glass hybrid fibre reinforced polymer (CGCG) using tungsten carbide, K20 drill bits. The effects of spindle speed, feed rate and tool geometry on surface roughness were evaluated and optimum cutting conditions for minimizing the aforementioned response was determined. Subsequently, response surface methodology (RSM) was utilised in finding the empirical relationships between experimental parameters and surface roughness based on the Taguchi results. The experimental analyses reveal that surface roughness is greatly influenced by feed rate and tool geometry rather than the spindle speed. This is due to the increment of feed that attributed to the increased strain rate and hence, deteriorated the surface roughness of the hybrid composite. The predicted results (via regression model) and theoretical results (via additivity law) were in good agreement with experiment results. This indicates that the regression model from response surface methodology (RSM) can be used to predict the surface roughness in machining of CGCG hybrid composite.


Author(s):  
Mostafa A. Abdullah  , Ahmed B. Abdulwahhab   ,   Atheer R.

In the curents study aimed to assess the effects of cutting conditions  (spindle speed, feed rate, tool diameter) parameters as input impact on material removal rate (MRR) and surface roughness (Ra) as output of steel (AISI 1015). A number of drilling experiments were conducted using the L9 orthogonal array on conventional drilling machine with use feed rate (0.038,0.076,0.203) mm/rev and spindle speed (132,550,930) rpm and tool diameter (11,15,20) mm HSS twist drills under dry cutting conditions. Analysis of variance (ANOVA) was employed to determine the most significant control factors affecting on surface roughness and MRR. The result shown the tool diameter the important factor effect with (64.08%) and (76.12%) on MRR and surface roughness respectively.


2018 ◽  
Vol 42 (2) ◽  
pp. 147-155 ◽  
Author(s):  
Rajkumar Tibadia ◽  
Koustubh Patwardhan ◽  
Dhrumil Shah ◽  
Dinesh Shinde ◽  
Rakesh Chaudhari ◽  
...  

In recent years, the major reason for the rejection of composite pipes in industrial applications is due to the poor quality of the drilled hole. This paper investigates the effect of drilling process parameters on the hole quality in composite pipes made of an aluminium core surrounded by polyethylene layers. An empirical model is designed for the two input variables using response surface methodology (central composite design). An experimental investigation is carried out to study the effect of spindle speed and feed rate on quality of drilled holes, especially circularity error. It is observed that a moderate spindle speed and low feed rate are most effective in minimizing the circularity error. Microstructural investigation of drilled hole surface is also carried out using scanning electron microscopy (SEM).


2014 ◽  
Vol 903 ◽  
pp. 45-50
Author(s):  
Prasanth Asok ◽  
Palanisamy Chockalingam

The use of aluminium alloy in the manufacturing industry has increased tremendously in the past decade mainly in the areas of aeronautics and automobiles. The ease of machinability of this material makes it a more desirable operand in manufacturing usage. Hence, in this research, a study was undertaken to perform a comparative analysis of dry and cold air drilling on 6061 aluminium alloy. The drill tool used in the drilling process was HSS Cobalt coated tool which has not featured in many research papers. Subsequently, the quality of each hole was identified based on the diameter accuracy of the hole and the surface roughness of the hole. A variation in the parameters was employed to identify the best feed rate and spindle speed that can accommodate a quality hole. In addition, during the drilling operations, force was measured to analyse the ensemble of parameters that present the highest and lowest force. Based on the data collected, an analysis was performed to identify the best quality hole. The force measured for cold air drilling was relatively lower than those measured in dry drilling primarily when high feed rate of 80 mm/min and high speed of 6000 rpm is used. The surface roughness and hole diameter does not differ much between cold air and dry drilling. Therefore, it is highly recommended that feed rate of 80 mm/min coupled with a spindle speed of 6000 rpm be used for drilling operations with a 5mm diameter tool.


2016 ◽  
Vol 835 ◽  
pp. 236-241
Author(s):  
P.Y.M. Wibowo Ndaruhadi ◽  
Bambang Santosa

Drilling process has many applications including making molds and dies, all requires different quality of the drilled hole. The aim of this study is to establish models and optimization of cutting parameter to get the best hole quality, including enlargement diameter, circularity error and surface roughness in drilling hardened steel. Drilling experiments have been performed using different cutting parameters (i.e. cutting speed and feed rate) and employ and uncoated carbide drill under flooded cooling. The experimental results show that both of the cutting speed and feed rate significantly affect all responses. Models for responses have been developed for investigation in this study, and their optimizations have been obtained, showing better quality of the drilled hole produced at higher cutting speed and lower feed rate. Desirability for the optimum criteria is 0.944 at the highest cutting speed (60 m/min) and lowest feed rate (0.05 mm/rev).


Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1628
Author(s):  
Mohd Fathullah Ghazali ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Shayfull Zamree Abd Rahim ◽  
Joanna Gondro ◽  
Paweł Pietrusiewicz ◽  
...  

This paper reports on the potential use of geopolymer in the drilling process, with respect to tool wear and surface roughness. The objectives of this research are to analyze the tool life of three different economy-grade drill bit uncoated; high-speed steel (HSS), HSS coated with TiN (HSS-TiN), and HSS-cobalt (HSS-Co) in the drilling of geopolymer and to investigate the effect of spindle speed towards the tool life and surface roughness. It was found that, based on the range of parameters set in this experiment, the spindle speed is directly proportional to the tool wear and inversely proportional to surface roughness. It was also observed that HSS-Co produced the lowest value of surface roughness compared to HSS-TiN and uncoated HSS and therefore is the most favorable tool to be used for drilling the material. For HSS, HSS coated with TiN, and HSS-Co, only the drilling with the spindle speed of 100 rpm was able to drill 15 holes without surpassing the maximum tool wear of 0.10 mm. HSS-Co exhibits the greatest tool life by showing the lowest value of flank wear and produce a better surface finish to the sample by a low value of surface roughness value (Ra). This finding explains that geopolymer is possible to be drilled, and therefore, ranges of cutting tools and parameters suggested can be a guideline for researchers and manufacturers to drill geopolymer for further applications.


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