Influence of Drill Geometry Parameters on Helical Point Micro Drilling Performance

2016 ◽  
Vol 836-837 ◽  
pp. 198-204
Author(s):  
Su Yan Zhang ◽  
Zhi Qiang Liang ◽  
Xi Bin Wang ◽  
Tian Feng Zhou ◽  
Pei Yan ◽  
...  
Keyword(s):  
Thrust Force ◽  
Helix Angle ◽  
Contributory Factor ◽  
Drilling Performance ◽  
Micro Drilling ◽  
Moderate Effect ◽  
Drill Point ◽  
Micro Drill ◽  
Selection Of ◽  
Small Point

Helical point micro-drill is characterized by a continuous helical flank instead of the piecewise planar flank, and its improved drilling performance is validated compared with planar drill point by some researchers. In this study, to analyze the effect of geometry parameters of helical point drill on the drilling performance, the micro-drills with different point angles, web thicknesses and helix angles of the flute are fabricated on a 6-axis CNC tool grinder, and a serial of micro-drilling experiments involving these drills on 1Cr18Ni9Ti austenitic stainless steel are carried out. In experiments, the drilling forces are measured and exit burrs are observed. Within a certain range of geometry parameters, thrust force increases with the increase of point angle and web thickness, and the decrease of the helix angle of the flute. The point angle is the main contributory factor for the thrust force followed by web thickness, while helix angle has a moderate effect on the force. Furthermore, poisson burr and rollover burr are generated with different point angles. Based on the results, a good selection of the helical point drill geometry parameters with small point angle, big helix angle and small web thickness are proposed to improve the micro-drilling performance.

A 5-Axis Coordinated CNC Grinding Method for the Flank of a Non-Coaxial Helical Micro-Drill with the Cylinder Grinding Wheel

2014 ◽  
Vol 1017 ◽  
pp. 654-659 ◽  
Author(s):  
Zhi Qiang Liang ◽  
Hong Chao Jian ◽  
Xi Bin Wang ◽  
Wen Xiang Zhao ◽  
Su Yan Zhang ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Grinding Wheel ◽  
Three Dimension ◽  
Drilling Performance ◽  
Grinding Method ◽  
Cnc Grinding ◽  
Micro Drilling ◽  
Drill Point ◽  
Micro Drill ◽  
Drill Tool

Micro-drilling become more widely used from precision mechanics to electronics. Nowadays, the main commercial tools are planar point micro-drills. However, that geometry often causes a high thrust force, high temperature, and rapid wear during micro-drilling. Furthermore, it is difficult to adjust the four flank surfaces to accurately intersect at one point, particularly when the drill diameter becomes smaller. To solve this problem, non-coaxial helical drills points have been proposed by some researchers, and is characterized by a continuous helical flank instead of the piecewise planar flank. Its drilling performance is improved compared with planar drill point. This study presents a 5-axis coordinated CNC grinding method of the non-coaxial helical drill flank. Mathematical models of the drill flank and its engagement line between cylinder grinding wheel and drill tool are established, and then the path of the grinding wheel with respect to the drill tool is obtained. In order to verify the availability of the proposed methods, three dimension (3D) grinding simulation of non-coaxial helical drills with diameter 0.5mm was carried out using the CAD software, and then were fabricated on a 6-axis Makino CNC tool grinder. The ground micro-drills examined by 3D laser scanning microscope show good identity with the simulated result. These indicate that the manufacturing model presented in this paper provides a practical and efficient method to grind the flank of a non-coaxial helical micro-drill.

Improvement of Chip Evacuation in Drilling of Lead-Free Brass Using Micro Drill

2014 ◽  
Vol 8 (6) ◽  
pp. 874-879 ◽  
Author(s):  
Hideharu Kato ◽  
◽  
Shingo Nakata ◽  
Noriaki Ikenaga ◽  
Hiroaki Sugita ◽  
...  
Keyword(s):  
Thrust Force ◽  
Helix Angle ◽  
Cutting Edge ◽  
Lead Free ◽  
Deep Drilling ◽  
Discharge Performance ◽  
Aspect Ratios ◽  
The Impact ◽  
Micro Drill ◽  
Small Holes

As the miniaturization of integrated circuits has progressed, the penetration holes of bonding jigs have become smaller. However, micro drills have a tendency to break when drilling small holes with high aspect ratios. Moreover, to reduce the impact on the environment, there has been a recent trend towards the use of lead-free brass as jig materials, but these are very difficult to drill. In the present study, small holes are drilled in lead-free brass using a micro drill, and the effects of web thinning, the helix angle, and the nick geometry on chip evacuation are investigated. The results indicate that drills with a helix angle of 15° have the longest tool life. The formation of a nick on the cutting edge is found to help decrease the thrust force during deep drilling. A drill with a relatively shallow nick perpendicular to the cutting edge have excellent chip discharge performance, and its cutting force is stable. Nick treatment effectively decreases the thrust force at a deep drilling position.

Mathematical Model and Simulation of Regrind Chisel Edge for Helical Micro-Drill

2006 ◽  
Vol 304-305 ◽  
pp. 550-554 ◽  
Author(s):  
W.J. Xiang ◽  
Zhi Xiong Zhou ◽  
S.J. Hu ◽  
J. Yang ◽  
J.P. Liang
Keyword(s):  
Mathematical Model ◽  
Geometric Model ◽  
Drilling Performance ◽  
Model And Simulation ◽  
Kinematic Relationship ◽  
Micro Drilling ◽  
Novel Method ◽  
Relationship Of ◽  
Micro Drill ◽  
Easy Operation

Micro-drills are becoming more and more important in precision and micro fabrications. They have been widely used in applications, e.g., precision and micro drilling. In this paper, a novel method is advanced and used for regrinding of chisel edges of helical micro-drills. In this method, a geometric model is established for the chisel edge regrinding. Based on the kinematic relationship of regrinding, the model simplifies machine movement so as to facilitate an easy operation. Computer simulation is applied to the regrinding process of the micro-drills. The results demonstrate that the proposed method is effective in regrinding chisel edges, which allows for a more reasonable distribution of the angles along the chisel edge of a drill, and enhances the drilling performance.

The Study of High Speed Micro-Drilling Performance and Machining Quality of Coated Micro-Drills with Zr-C:H Coatings

2012 ◽  
Vol 591-593 ◽  
pp. 342-346 ◽  
Author(s):  
Wen Hsien Kao ◽  
Yan Liang Su ◽  
Sun Hui Yao ◽  
H.C. Huang ◽  
M.S. Chen
Keyword(s):  
High Speed ◽  
Printed Circuit Board ◽  
Circuit Board ◽  
Hole Drilling ◽  
Closed Field ◽  
Machining Performance ◽  
Machining Quality ◽  
Drilling Performance ◽  
Micro Drilling ◽  
Micro Drill

The Zr-C:H coatings with various C2H2 flow rate were deposited on micro-drills (a diameter of 0.2 mm) used a closed field unbalanced magnetron sputtering system. The ultrahigh speed (drilling speed of 160000 rpm) through-hole drilling printed circuit board tests used to evaluate the drilling performance of the coated micro-drills. The rejection criteria of service lives of the coated micro-drills were evaluated using two different criteria: (1) a nail head ratio greater than 1.5; (2) a drilled hole surface roughness greater than 25.4 μm. Adopting a service life criterion of a nail head ratio of 1.5, the Zr-C:H-5 coating possesses the optimal high-speed machining performance, which yields a micro-drill lifetime of above 6000 drilled holes. It represents a three-fold improvement on that of an uncoated micro-drill and it also improves machining quality.

Improvement in Drilling Performance of Micro Compound Tool

2010 ◽  
Vol 447-448 ◽  
pp. 96-100
Author(s):  
Osamu Ohnishi ◽  
Hiromichi Onikura ◽  
Toshihiko Eguchi ◽  
Muhammad Aziz ◽  
Toshiro K. Doi ◽  
...  
Keyword(s):  
Ultrasonic Vibration ◽  
Small Difference ◽  
Burr Formation ◽  
Diamond Grit ◽  
Part Geometry ◽  
Drilling Performance ◽  
Large Size ◽  
Micro Drilling ◽  
Micro Drill ◽  
Secondary Cutting

The present paper deals with the development of micro compound tools and their application to the micro drilling. The micro compound tool consists of a micro drill part and an electroplated part with a nominal finishing diameter of 100 µm and they are fabricated by grinding and electroplating processes. Fabricated tools are used in drilling tests with or without ultrasonic vibration. Influences of drill part geometry on burr formation and influences of diamond grit size on peeling of the electroplating layer are investigated. As the results, secondary cutting edges do not seem to have remarkable ability for reduction of burrs. And large size of diamond grit at the electroplated part of a micro compound tool with a small difference between a diameter of electroplated part and a diameter of drill part seems to be effective in preventing peeling of the electroplating layer and improving drilling performance.

Experimental Investigation of Tool Breakage in Micro Drilling of EN AW-5083 Aluminium

2013 ◽  
Vol 581 ◽  
pp. 119-124 ◽  
Author(s):  
Tibor Szalay ◽  
Karali Patra ◽  
Balázs Zsolt Farkas
Keyword(s):  
Experimental Investigation ◽  
Thrust Force ◽  
Hole Drilling ◽  
Experimental Measurements ◽  
Tool Breakage ◽  
Monitoring Method ◽  
Micro Drilling ◽  
Micro Hole ◽  
High Thrust ◽  
Micro Drill

Nowadays micro hole drilling is more and more applied machining operation. Because of less than 1 millimeter diameter, and of the relatively high thrust force, micro drills are more easily break than conventional ones. In this paper the experiences of micro drilling tests are summarize in order to demonstrate that measuring thrust force is efficient way to recognize the tool breakage. In order to evaluate the micro drill breakage monitoring method the authors carried out experimental measurements varying the cutting conditions, too.

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

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.

Influence of chisel edge thinning on helical point micro-drilling performance

2018 ◽  
Vol 99 (9-12) ◽  
pp. 2863-2875 ◽  
Author(s):  
Haixin Guo ◽  
Zhiqiang Liang ◽  
Xibin Wang ◽  
Tianfeng Zhou ◽  
Li Jiao ◽  
...  
Keyword(s):  
Drilling Performance ◽  
Micro Drilling

Effects of Twist Drill Point Angle on Thrust Force and Delamination Factor in Hybrid Fiber Composites Drilling

2014 ◽  
Vol 564 ◽  
pp. 501-506 ◽  
Author(s):  
Mohd Azuwan Maoinser ◽  
Faiz Ahmad ◽  
Safian Shariff ◽  
Tze Keong Woo
Keyword(s):  
Feed Rate ◽  
Thrust Force ◽  
Polymeric Composite ◽  
Drilling Process ◽  
Twist Drill ◽  
Fiber Reinforced ◽  
Hybrid Fiber ◽  
Frp Composites ◽  
Delamination Factor ◽  
Drill Point

Drill point angle of twist drill has a significant effect on thrust force and delamination factor on drilled holes in fiber reinforced polymer (FRP) composites. In this study, three drill point angle of twist drill; 85°, 118° and 135° were used to drill holes in hybrid fiber reinforced polymeric composite (HFRP). HFRP composites were fabricated using vacuum infusion molding (VIM) technique. The test samples were cured at 90°C for two hours. In drilling process various drill point angle and feed rate were employed to investigate the effect of both parameters on thrust force and delamination factor when drilling the HFRP composite. The results showed that small drill point angle and low feed rate can reduce the thrust force leading to the reduction of damage factor at the holes entrance and exit.

Prediction of Thrust and Torque for Multifacet Drills (MFD)

1994 ◽  
Vol 116 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Horng-Tsann Huang ◽  
Cheng-I Weng ◽  
Chao-Kuang Chen
Keyword(s):  
Analytical Model ◽  
Theoretical Method ◽  
Cutting Mechanics ◽  
Drilling Performance ◽  
Proposed Model ◽  
Wide Range ◽  
Drill Point ◽  
Thrust And Torque

A multifacet drill (MFD), developed around 1953, has been used to improve the drilling performance by modifying the drill point geometry. A theoretical method for predicting the thrust and torque for an MFD is developed on the basis of the cutting mechanics for a conventional drill. Experiments show the proposed model is quite satisfactory for a wide range of applications. Also, from the analytical model the effects of the major features of the drill point geometry on thrust and torque can be studied.

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