Investigation of Burr in High Speed Microdrilling

2013 ◽  
Vol 278-280 ◽  
pp. 389-392
Author(s):  
Mohammad Yeakub Ali ◽  
A. R. Mohamed ◽  
Nor Fadila ◽  
Noor Hannah

This paper discusses burr in microdrilling that affect forms and functions of parts. The effects of microdrilling parameters on burr length and width are identified. The experiment was conducted using Mikrotools DT110 machine with one millimetre diameter of HSS on copper workpiece. Burr heights in terms of burr length and burr width were measured by using scanning electron microscope. The data was analyzed using Taguchi method to find the optimum micro-drilling process parameter for minimizing the burr height. The relationship among spindle speed, feed rate and burr has been developed. It is found that feed rate is the most influential factors on the burr height. The desirability of getting the minimum burr height is 72% and the optimum parameters are 30000 rpm spindle speed and 0.2 mm/min feed rate.

2020 ◽  
Vol 402 ◽  
pp. 125-130
Author(s):  
Muhammad Tadjuddin ◽  
Suhaeri ◽  
Muhammad Dirhamsyah ◽  
Aulia Udink ◽  
Fatur Rahmatsyah

The micro-drill is one of the manufacturing processes that is developing, especially in the electronics, aerospace, pharmaceutical, and automotive industries. This paper describes the results of the high-speed microdrill process in stainless steel. The drilling process is used to make the micro screen. The cutting tool material is tungsten carbide with a diameter of 0.2 mm. Drilling holes arranged in a honeycomb configuration. The machining parameters used are spindle speed of 20,000 rpm, 22,000 rpm, 24,000 rpm, and feed rate of 1 mm/min, 1.5 mm/min, 2 mm/min. Micro-drilling holes are visually analyzed using a Scanning Electron Microscope (SEM) to measure the accuracy of the hole dimensions. The results of the machining process found that the most significant deviation of the hole dimension size with a value of 0.276 mm occurred at a spindle speed of 20,000 rpm with a feed of 1 mm/min. While the deviation of the smallest hole size with a value of 0.2019 mm occurred at a spindle speed of 24,000 rpm with a feed of 2 mm/min, these results conclude that the accuracy of the hole dimensions will increase in proportion to the increase in spindle speed and feeding.


2020 ◽  
Vol 402 ◽  
pp. 73-80
Author(s):  
Teuku Firsa ◽  
Muhammad Tadjuddin ◽  
Aulia Udink ◽  
Iskandar Hasanuddin

Micromachining technology is a challenge in industrial production to meet the demand for components for machinery. In this research, a study of the best parameters was required to produce the best hole accuracy and the lowest burr formation in the inlet and exit holes using micro-drilling. The work-piece material and cutting tool used respectively was a brass plate with a thickness of 0.5 mm and a micro drill with a diameter of 0.2 mm commonly used for electronic PCBs. The quality of holes was measured and observed by using a stereomicroscope (optical equipment). This microscope can zoom up to 50x objects to facilitate measurement. The microscope was attached by using a digital camera type YW-200 so that the object of observation could be measured using a computer. The result shows that the largest deviation of hole diameter (0.217 mm) occurred at a spindle speed of 14,000 rpm with the lowest feed rate (5 mm/min). Meanwhile, the smallest deviation of hole diameter (0.202 mm) occurred at a spindle speed of 20,000 rpm with a maximum feed rate of 10 mm/min. The maximum burr height (0.050 mm) occurred at a spindle speed of 17,000 rpm and a feed rate of 10 mm/min. In addition, the minimum burr height (0.038 mm) occurred at a spindle speed of 14,000 rpm and a feed rate of 5 mm/min. Therefore, it can be concluded that the deviation of hole diameter was inversely proportional to the spindle speed, and the height of the burr formation was directly proportional to the feed rate.


Carbon Fiber Reinforced Polymer (CFRP) is extensively used in aircraft and automotive industries due to it exceptional material properties such as high strength to weight ratio and corrosion resistance. Nevertheless, micro drilling process of CFRP material poses various challenge as it has irregular material properties along the structure. High cutting force which lead to poor hole quality is one of the issues that always occur when drilling this material. Hence, the understanding on the relationship between process parameter and material behavior is vital to achieve optimum performance of machining process. The experiment was carried out using 2-level factorial design with variable spindle speed range of 8,000 – 12,000 rpm and feed rate range of 0.01-0.015 mm/rev. Micro drill bit with diameter of 0.9 mm was used and new fresh drill were used for every run to avoid tool wear effect. As a result, lower thrust force of 6.3742 N is obtained from the combination of spindle speed 10k rpm and feed rate 0.0125 N. Therefore, it can be concluded that, optimum parameter falls between the range of 8,000 – 12,000 rpm of spindle speed and 0.01-0.015 mm/rev of feed rate. Validation of the optimum parameter suggested from 2-level factorial which are 8,000 rpm and 0.01 mm/rev is executed. The final result obtained shows 4.5% of error from targeted value and this result is absolutely acceptable and portray the reliability of the experiment.


Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 854
Author(s):  
Muhammad Aamir ◽  
Khaled Giasin ◽  
Majid Tolouei-Rad ◽  
Israr Ud Din ◽  
Muhammad Imran Hanif ◽  
...  

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.


2015 ◽  
Vol 1115 ◽  
pp. 12-15
Author(s):  
Nur Atiqah ◽  
Mohammad Yeakub Ali ◽  
Abdul Rahman Mohamed ◽  
Md. Sazzad Hossein Chowdhury

Micro end milling is one of the most important micromachining process and widely used for producing miniaturized components with high accuracy and surface finish. This paper present the influence of three micro end milling process parameters; spindle speed, feed rate, and depth of cut on surface roughness (Ra) and material removal rate (MRR). The machining was performed using multi-process micro machine tools (DT-110 Mikrotools Inc., Singapore) with poly methyl methacrylate (PMMA) as the workpiece and tungsten carbide as its tool. To develop the mathematical model for the responses in high speed micro end milling machining, Taguchi design has been used to design the experiment by using the orthogonal array of three levels L18 (21×37). The developed models were used for multiple response optimizations by desirability function approach to obtain minimum Ra and maximum MRR. The optimized values of Ra and MRR were 128.24 nm, and 0.0463 mg/min, respectively obtained at spindle speed of 30000 rpm, feed rate of 2.65 mm/min, and depth of cut of 40 μm. The analysis of variance revealed that spindle speeds are the most influential parameters on Ra. The optimization of MRR is mostly influence by feed rate. Keywords:Micromilling,surfaceroughness,MRR,PMMA


2017 ◽  
Vol 748 ◽  
pp. 254-258
Author(s):  
Chang Yi Liu ◽  
Bai Shou Zhang ◽  
Suman Shrestha

Drilling experiments of titanium alloy Ti6Al4V were conducted. Taking the speed and feed as the process variables, a set of experimental cutting forces are obtained and compared. From the experimental results it is concluded that within the experimental extent the thrust force and torque of drilling process rises with the feed rate. The lower spindle speed resulted in the greater amount of thrust. Feed rates have greater influence on the thrust force than the spindle speed. The combination of greater feed rate and lower spindle speed results in the maximum amount of thrust. However, combination of greater feed rate and spindle speed resulted in maximum amount of torque.


2011 ◽  
Vol 188 ◽  
pp. 429-434 ◽  
Author(s):  
L.P. Yang ◽  
Li Xin Huang ◽  
Cheng Yong Wang ◽  
L.J. Zheng ◽  
Ping Ma ◽  
...  

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.


2010 ◽  
Vol 447-448 ◽  
pp. 836-840 ◽  
Author(s):  
Eiichi Aoyama ◽  
Toshiki Hirogaki ◽  
Keiji Ogawa ◽  
Satoshi Nojiri ◽  
Yutaka Takeda

A drilling technique using micro-drills of 0.2 mm or less in diameter and a super-high-speed spindle of 160000 rpm or more has been developed for drilling ultra-micro holes in printed wiring boards (PWBs). The drilling process requires higher reliability and quality to maintain the reliability of the electrical connection between circuit layers. On the other hand, higher processing efficiency is also required in PWBs manufacturing. To maintain high productivity, drilling is normally performed using a non-step method, but heat damage called B-RING occurs around the drilled holes with this method. To solve these problems without the loss of processing efficiency, we applied the rapid-feed step-drilling cycle method. We investigated the B-RING for drilling quality and evaluated the drilling time for processing efficiency under various drilling conditions. We found that using a rapid-feed step-drilling cycle with an appropriate number of steps and feed rates ensures a higher level of hole quality and processing efficiency compared with the conventional non-step drilling.


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.


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