Influence of Tool Blunting on the Value of the Axial Component of the Cutting Force and the Drilling Process

2021 ◽  
Vol 410 ◽  
pp. 692-696
Author(s):  
Alexey N. Shulgin ◽  
Olesya A. Chuprina ◽  
Vasiliy V. Pykhov
Keyword(s):  
Copper Foil ◽  
Printed Circuit Board ◽  
Cutting Tool ◽  
Circuit Board ◽  
Tool Geometry ◽  
Axial Component ◽  
Drilling Process ◽  
Special Equipment ◽  
Printed Circuit

One of the main technological criteria affecting the quality of drilling the holes is the correct geometry of a cutting tool and the amount of its wear. The determination of the “critical” amount of a drill wear is possible only through the indirect way, in particular by the presence of the copper foil burrs at the tool output from the printed circuit board, since with the up-to-date degree of integration of micro-assemblies, the main part of the processed holes has the diameter of about 0.6-0.8 mm, and it is quite challenging to determine the tool wear without special equipment, and in conditions of mass production it is almost impossible. A number of industrial experiments with the hard-alloy drills of standard sharpening geometry of various amount of wear was carried out in order to assess the influence of the cutting tool geometry and the amount of wear on the drilling process. To assess the quality of the processed holes, the chip size (Lch), the micro-roughness of the holes (Ra) and the size of the copper foil burrs at the output of the workpieces (Hb) were additionally measured with a specialized precision tool. In total, 1500 holes were drilled at each previously determined operating mode. The “critical” value of the tool blunting, the maximum allowable values of Lch,Ra and Hbwere practically defined in the course of work. On the basis of the conducted experiments, the threshold values of the axial feed speeds for the work of the “worn out” and “blunted” tool were defined. In addition, the general recommendations were formulated for the operator when drilling the foiled fiberglass and eliminating mass defects at printed circuit board manufacture.

Thermal Model of Printed Circuit Board Plated-Through Hole under One-Sided Heating Conditions

2021 ◽  
Vol 26 (5) ◽  
pp. 426-431
Author(s):  
V.A. Sergeev ◽  
◽  
A.M. Khodakov ◽  
M.Yu. Salnikov ◽  
◽  
...  
Keyword(s):  
Quality Control ◽  
Thermal Resistance ◽  
Thermal Model ◽  
Printed Circuit Board ◽  
Circuit Board ◽  
Thermal Models ◽  
Printed Circuit ◽  
Plated Through Hole ◽  
Through Hole

Thermal methods of quality control of the plated-through hole (PTH) of printed circuit board (PCB) are based on thermal models. However, known thermal models of PTH take no account of heat transfer to PCB material thus not allowing for PTH heat characteristic tying up with adhesion quality. In this work, an axisymmetric thermal model of a single-layer PCB PTH under one-sided heating conditions is considered. It was shown that the ratio of the temperature increments of the upper (heated) and lower end of the PTH in the considered range of heating power does not depend on the power level. A linear thermal equivalent scheme of the PTH has been proposed, which includes the longitudinal thermal resistance of the PTH metallization, de-termined by the parameters and quality of the metallization layer, the thermal resistance, which determines the convection heat exchange between the ends of the PTH with the adjacent PCB surface and the environment, and the thermal resistance of the area of the PCB material adjacent to the PTH, depending on the quality of the metallization adhesion and the PCB dielectric. Thermal equivalent circuit parameters determined by the ratio of the temperature increment of the upper and lower ends of the PTH and their difference can serve as the basis for the development of a nondestructive inspection procedure for PTH quality control by way of its unilateral heating, for example, by a laser beam.

Patterned ZnO Nanowires between Interdigitated Electrodes by Integrating Hydrothermal Approach with Photolithography Process

2020 ◽  
Vol 990 ◽  
pp. 283-287
Author(s):  
Yaw Jen Chang
Keyword(s):  
Copper Foil ◽  
Printed Circuit Board ◽  
Simple Approach ◽  
Zno Nanowires ◽  
Circuit Board ◽  
Interdigitated Electrodes ◽  
Printed Circuit ◽  
Lift Off ◽  
Hydrothermal Approach ◽  
Photolithography Process

This paper presents a simple approach to selectively synthesize the ZnO nanowires between interdigitated electrodes by integrating the hydrothermal method with the photolithography process. The printed circuit board (PCB) was adopted as the substrate. Interdigitated electrodes were fabricated by etching the copper foil of PCB. Then, both the positive and negative photoresists were used to control the growth of nanowires through lift-off concept. No costly materials and expensive apparatuses are required. Biotin–streptavidin reaction was used as an example to examine this proposed device. When histidine-tagged biotin was added and the reaction of biotin–streptavidin was completed, the distinguishable I-V curves were detected, respectively. The experimental results reveal that this proposed device is sensitive.

Research on fixture hole drilling quality of printed circuit board

2013 ◽  
Vol 14 (4) ◽  
pp. 525-534 ◽  
Author(s):  
Xiaohu Zheng ◽  
Dapeng Dong ◽  
Lixin Huang ◽  
Qinglong An ◽  
Xibin Wang ◽  
...  
Keyword(s):  
Printed Circuit Board ◽  
Circuit Board ◽  
Hole Drilling ◽  
Printed Circuit ◽  
Drilling Quality

The Investigation of Thrust Force of Printed Circuit Board Drilling

2011 ◽  
Vol 496 ◽  
pp. 259-265 ◽  
Author(s):  
Li Juan Zheng ◽  
Cheng Yong Wang ◽  
Yun Peng Qu ◽  
Li Peng Yang ◽  
Yue Xian Song
Keyword(s):  
Tool Wear ◽  
Feed Rate ◽  
Copper Foil ◽  
Printed Circuit Board ◽  
Thrust Force ◽  
Spindle Speed ◽  
Circuit Board ◽  
Wall Roughness ◽  
Printed Circuit ◽  
The Difference

This work is focused on the investigation of the influence of the materials of PCB, feed rate, spindle speed and tool wear on thrust force when drilling PCB using 0.3 mm diameter cemented tungsten carbide drills. The results indicate that thrust force increases with feed rate and drill wear, but decreases with spindle speed firstly and then increases with it within the cutting range tested. Thrust force caused by the copper foil is much larger than that caused by the epoxy glass fiber cloth when feed rate is low. However, the difference between them decreases as feed rate increases. The thickness of nail head increases with thrust force. The accuracy of hole location increases with thrust force firstly but decreases afterward. The influence of thrust force on hole wall roughness is not obvious.

scholarly journals Comparative assessment of the conditions of direct and electrochemical metallization of blind holes of multilayer printed circuit boards

2019 ◽  
Vol 58 (5) ◽  
pp. 98-104
Author(s):  
Radic R. Latypov ◽  
◽  
Alexandra O. Desyatova ◽  
Sergey V. Golybev ◽  
Larisa N. Maskaeva ◽  
...  
Keyword(s):  
Printed Circuit Boards ◽  
Printed Circuit Board ◽  
Comparative Assessment ◽  
Copper Coating ◽  
Circuit Board ◽  
Circuit Boards ◽  
Drilling Depth ◽  
Printed Circuit ◽  
Catalyst Layers

The metal blind holes acting as interconnectors allow significantly reduce the number of layers, increase the efficiency of trace and decrease interference between the holes and signal conductors in the high frequency printed circuit boards. In this work, a comparative assessment of the conditions of direct and electrochemical metallization blind holes with diameters: 0,2; 0.25; 0.3; 0.4; 0.6; 0.8; 1.0 mm and a drilling depth of 0.5 mm located on experimental four-layer multilayer printed circuit boards, differing in the method of applying a conductive and copper coating was carried out. It has been established that in case non-fulfillment of mandatory conditions for the production of blind holes, in particular the aspect ratio is less than or equal to unity, incomplete metallization of the walls and especially the bottom of the holes is observed. The ways of combining the processes of direct and electrochemical metallization of holes, which provide the required thickness and quality of the copper coating at reduction of general duration of operations have been proposed based on the experimental data obtained during the work with multilayer printed boards. Also it has been established that the joint placement of blind holes with a smaller and larger diameter on one multilayer printed circuit board requires a more long direct metallization in combination with electrochemical at low values of current density. Copper films deposited on the walls of the holes and on the surface of the contact pads, regardless of the proposed way of metallization, have a highly dispersed structure. The composition of the palladium catalyst layers has been studied by energy dispersive analysis. The conductive coating on the blind hole’s walls contains between 1.55 and 6.77 at.% palladium.

The entry drilling process of flexible printed circuit board and its influence on hole quality

Circuit World ◽  
2015 ◽  
Vol 41 (4) ◽  
pp. 147-153 ◽  
Author(s):  
Lijuan Zheng ◽  
Chengyong Wang ◽  
Xin Zhang ◽  
Yuexian Song ◽  
Lunqiang Zhang ◽  
...  
Keyword(s):  
Printed Circuit Board ◽  
Circuit Board ◽  
Drilling Process ◽  
Hole Quality ◽  
Location Accuracy ◽  
Content Type ◽  
Printed Circuit ◽  
Flexible Printed Circuit ◽  
Micro Drilling ◽  
Micro Hole

Purpose – The purpose of this study is to present the entry drilling process of flexible printed circuit board (FPCs) and its influence on hole quality, especially hole location accuracy. Compared with the traditional PCB drilling process, the technology of drilling FPCs is facing more problems, such as hole location accuracy, smear on the hole wall surface, burned hole wall surface, etc. Moreover, the materials of FPCs are quite different from the rigid printed circuit boards (RPCs). FPCs no longer contain glass fiber cloths to reinforce resin, resulting in flexibility. Micro-hole quality is the most important issue in FPC drilling. Suggestions were given to obtain higher hole qualities and higher FPC reliability. Design/methodology/approach – The entry drilling process of FPC with different kind of entry boards was observed by a high-speed camera. The hole qualities of FPC micro-drilling, especially hole location accuracy and hole entrance quality, were measured. The relationship between entry boards and hole quality was analyzed. Findings – Significant sliding occurred when drilling FPC with using no-entry board or pure aluminum plate entry board. On the contrary, no significant sliding occurred when using LC-110 or resin-coated aluminum foil (MVC) entry boards. The type, thickness and use-pattern of entry boards influenced hole location accuracy of FPCs seriously. In addition, entry board also influenced the micro-hole entrance quality and micro-hole diameter. The entrance quality of drilling FPC with LC-110 entry board was the best. The diameter variation of drilling FPC with MVC entry board was the smallest. The hole location accuracy decreased as the thickness of entry board increased. Thus, the best use-pattern of entry board was putting a LC-110 under MVC entry board, resulting in best entrance quality and hole location accuracy. Originality/value – The technology and manufacturing of FPCs in China are obviously behind. Research of FPCs micro-drilling and research data are lacking so far. Thus, it is most necessary to improve the technology level of FPCs micro-drilling in China. Researches on hole quality, especially hole location accuracy of FPCs drilling, were performed in this paper. Suggestions were given to obtain higher hole quality of FPCs.

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