scholarly journals Effects of Thin Pipe Electrodes with Grooves in Small Deep Hole EDM

2021 ◽  
Vol 26 (0) ◽  
pp. 46
Author(s):  
Hideki Takezawa ◽  
Hiroki Toyoda ◽  
Kenta Yuasa
Keyword(s):  
Deep Hole

Deep Hole Drilling Technique (DHD)

2019 ◽  
Vol 88 (6) ◽  
pp. 485-488
Author(s):  
Shinji KAWAI ◽  
Takuya NAGAI ◽  
Shigetaka OKANO
Keyword(s):  
Hole Drilling ◽  
Deep Hole ◽  
Deep Hole Drilling ◽  
Drilling Technique

Deep hole trap properties ofp‐type ZnSe grown by molecular beam epitaxy

1993 ◽  
Vol 63 (2) ◽  
pp. 191-193 ◽  
Author(s):  
K. Ando ◽  
Y. Kawaguchi ◽  
T. Ohno ◽  
A. Ohki ◽  
S. Zembutsu
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Hole Trap ◽  
Deep Hole

scholarly journals Cooperative Control Mechanism of Long Flexible Bolts and Blasting Pressure Relief in Hard Roof Roadways of Extra-Thick Coal Seams: A Case Study

2021 ◽  
Vol 11 (9) ◽  
pp. 4125
Author(s):  
Zhe Xiang ◽  
Nong Zhang ◽  
Zhengzheng Xie ◽  
Feng Guo ◽  
Chenghao Zhang
Keyword(s):  
Coal Seam ◽  
Cooperative Control ◽  
Field Tests ◽  
Surrounding Rock ◽  
Deep Hole ◽  
Coal Seams ◽  
Thick Coal Seam ◽  
Structure Damage ◽  
Hard Roof

The higher strength of a hard roof leads to higher coal pressure during coal mining, especially under extra-thick coal seam conditions. This study addresses the hard roof control problem for extra-thick coal seams using the air return roadway 4106 (AR 4106) of the Wenjiapo Coal Mine as a case study. A new surrounding rock control strategy is proposed, which mainly includes 44 m deep-hole pre-splitting blasting for stress releasing and flexible 4-m-long bolt for roof supporting. Based on the new support scheme, field tests were performed. The results show that roadway support failure in traditional scenarios is caused by insufficient bolt length and extensive rotary subsidence of the long cantilever beam of the hard roof. In the new proposed scheme, flexible 4-m-long bolts are shown to effectively restrain the initial expansion deformation of the top coal. The deflection of the rock beam anchored by the roof foundation are improved. Deep-hole pre-splitting blasting effectively reduces the cantilever distance of the “block B” of the voussoir beam structure. The stress environment of the roadway surrounding rock is optimized and anchorage structure damage is inhibited. The results provide insights regarding the safe control of roadway roofs under extra-thick coal seam conditions.

scholarly journals Wear Resistance Improvement of Cemented Tungsten Carbide Deep-Hole Drills after Ion Implantation

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 239
Author(s):  
Dmitrij Morozow ◽  
Marek Barlak ◽  
Zbigniew Werner ◽  
Marcin Pisarek ◽  
Piotr Konarski ◽  
...  
Keyword(s):  
Ion Implantation ◽  
Tungsten Carbide ◽  
Photoelectron Spectroscopy ◽  
Secondary Ion Mass Spectrometry ◽  
Carbon Layer ◽  
Hole Drilling ◽  
Deep Hole ◽  
Tungsten Nitrides ◽  
Lubrication Effect ◽  
Secondary Ion

The paper is dedicated to the lifetime prolongation of the tools designed for deep-hole drilling. Among available methods, an ion implantation process was used to improve the durability of tungsten carbide (WC)-Co guide pads. Nitrogen fluencies of 3 × 1017 cm−2, 4 × 1017 cm−2 and 5 × 1017 cm−2 were applied, and scanning electron microscope (SEM) observations, energy dispersive spectroscopy (EDS) analyses, X-ray photoelectron spectroscopy (XPS) and Secondary Ion Mass Spectrometry (SIMS) measurements were performed for both nonimplanted and implanted tools. The durability tests of nonimplanted and the modified tools were performed in industrial conditions. The durability of implanted guide pads was above 2.5 times more than nonimplanted ones in the best case, presumably due to the presence of a carbon-rich layer and extremely hard tungsten nitrides. The achieved effect may be attributed to the dissociation of tungsten carbide phase and to the lubrication effect. The latter was due to the presence of pure carbon layer with a thickness of a few dozen nanometers. Notably, this layer was formed at a temperature of 200 °C, much smaller than in previously reported research, which makes the findings even more valuable from economic and environmental perspectives.

scholarly journals Temperature monitoring in the subsurface during single lip deep hole drilling

2020 ◽  
Vol 87 (12) ◽  
pp. 757-767
Author(s):  
Robert Wegert ◽  
Vinzenz Guski ◽  
Hans-Christian Möhring ◽  
Siegfried Schmauder
Keyword(s):  
Cutting Parameters ◽  
Drill Hole ◽  
Machining Process ◽  
Hole Drilling ◽  
Drilling Process ◽  
Deep Hole ◽  
Machining Processes ◽  
Deep Hole Drilling ◽  
Feed Force ◽  
Cutting Zone

AbstractThe surface quality and the subsurface properties such as hardness, residual stresses and grain size of a drill hole are dependent on the cutting parameters of the single lip deep hole drilling process and therefore on the thermomechanical as-is state in the cutting zone and in the contact zone between the guide pads and the drill hole surface. In this contribution, the main objectives are the in-process measurement of the thermal as-is state in the subsurface of a drilling hole by means of thermocouples as well as the feed force and drilling torque evaluation. FE simulation results to verify the investigations and to predict the thermomechanical conditions in the cutting zone are presented as well. The work is part of an interdisciplinary research project in the framework of the priority program “Surface Conditioning in Machining Processes” (SPP 2086) of the German Research Foundation (DFG).This contribution provides an overview of the effects of cutting parameters, cooling lubrication and including wear on the thermal conditions in the subsurface and mechanical loads during this machining process. At first, a test set up for the in-process temperature measurement will be presented with the execution as well as the analysis of the resulting temperature, feed force and drilling torque during drilling a 42CrMo4 steel. Furthermore, the results of process simulations and the validation of this applied FE approach with measured quantities are presented.

Optimization of roundness error in deep hole drilling using moth-flame optimization

2021 ◽  
Author(s):  
Anis Farhan Kamaruzaman ◽  
Azlan Mohd Zain ◽  
Noordin Mohd Yusof ◽  
Farhad Nadjarian ◽  
Rozita Abdul Jalil
Keyword(s):  
Hole Drilling ◽  
Deep Hole ◽  
Roundness Error ◽  
Deep Hole Drilling
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