• Title/Summary/Keyword: Drill diameter

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Enhancement of Life Time for PCB (Printed Circuit Board) Drill Bit by Nitrogen Ion Implantation

  • Lee, Chan-Young;Lee, Jae-Sang;Kim, Bum-Suk
    • Transactions on Electrical and Electronic Materials
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    • v.9 no.5
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    • pp.206-208
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    • 2008
  • Implantation of metals and ceramics with ions of nitrogen and other species has improved surface properties such as friction, wear and corrosion in numerous industrial applications. In recent years, PCB drills tend to be more minimized increasingly as the electronics components have been more highly accumulated and minimized. Therefore nitrogen ion implantation was performed onto PCB drill (0.15 & 0.3 mm in diameter), in order to investigate mechanical properties of WC-Co cermets surface through Nano-indentation tests. PCB drill was implanted at energy of 70 keV, 90 keV, 120 keV and with the dose range of $1{\times}10^{17}$ and $5{\times}10^{17}\;ions/cm^{2}$. After ion implantation, WC-Co PCB drill bits was tested in actual operating situation to apply cutting tools industry and is concluded that the life time of nitrogen ion implanted PCB drills is one and a half times longer than the unimplanted.

Downward Method of H-PILE Alternative Materials of Percusion Rotary Drill (PRD시공시 H-PILE 대체 자재로 원가절감 할수 있는 공법 사례)

  • Lee, Wang-Hee;Lee, Il-Jae;Iim, Si-Nae
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2014.11a
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    • pp.199-202
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    • 2014
  • In recent years the downtown, Top-down method has been applied in a major method to solve the complaints due to noise, vibration, dust and safety issues such as cracking due to settlement when the excavation close to the building. Until it is installed underground permanent foundation, the Pre-founded Column is a pile foundation as well as a column to bear the upper construction load. The Pre-founded Column is constructed by PRD method generally. The EnP(Enlarging Pile) method can be expanded locally boring diameter of the embedment zone as compared to the PRD method existing general. Since the bearing capacity is increased by the boring diameter is expanded, the embedment length is reduced, the construction cost is reduced.

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A study on the Drilling according to the Stacking Sequence of the CFRP (탄소섬유강화플라스틱의 적층구성에 따른 드릴 가공에 관한연구)

  • Kim, S.B.;Shin, H.G.;Kim, T.Y.
    • Journal of the Korean Society of Mechanical Technology
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    • v.13 no.2
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    • pp.1-7
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    • 2011
  • The CFRP composite has a lot of merits such as mechanical characteristic, light and thermal resistance. For these merits, CFRP is applied to so many industrial area. In order to use the composite materials in the aircraft structures or machine elements, accurate surfaces for bearing mounting or joints must be provided, which require precise, machining. In this study, the specimens differentiating the stacking sequence of 5kinds were used. When drilling the carbon fiber reinforced plastics, it was checked on whether the stacking sequence reached any effect on the cutting force. Also relationship between the drill diameter is examined from the drilling experiment, which is the drilling of Fabric, Unidirectional specimen with ∅6mm, ∅10mm, ∅12mm cemented carbide drill. Considering cutting force and drilling diameter, the results are analyzed.

Parameters Affecting the TiN Coated Machining Tool's Life (질화 티타늄이 코팅된 절삭공구의 수명에 영향을 미치는 인자)

  • 최병대;김동수
    • Journal of the Korean institute of surface engineering
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    • v.28 no.2
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    • pp.77-82
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    • 1995
  • In this study, we examined the relationships between the coating film's properties, such as microhardness, adhesion of coating fil $m_strate, and machining tool's life time. Samples were prepared by coating TiN on the 5.5 diameter twist drills using reactive ion plating technology, For measuring microhardness and adhesion of fil $m_strate, HSS plate was used for substrate. TiN coated drill's life time was dependent on the adhesion of fil $m_strate and averagely increased by several ten times more than uncoated drill's. The major parameter affecting TiN coated drill's life time was the strong adhesion between coating film and substrate.ate.

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Standardization of Cautious blasting (정밀발파의 표준화(下))

  • Huh, Ginn
    • Journal of the Korean Professional Engineers Association
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    • v.23 no.6
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    • pp.41-46
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    • 1990
  • First of all, Under given condition such as bit gage of 36mm Drill bit with right class of jack-logs experimental test carried out from two face of Bench, firing of each hole brought 90 degree Angle face and them measured length of Burden and charged ammount of powder as following. (equation omitted) A=Activated Area A=ndi=m S=Peripheral length of Charged. room Ca=Rock Coeffiecency d : di=Hole diameter When constructed subway of Seoul in 1980 the blasting works increased complaint of ground vibration. in order to prevent the damage to structures. Some empirical equations were made as follows on condition with Jackleg Drill (Bit Gage ø 36mm) and within 30 meter distance between blasting site and structures. V=K(D / W)$\^$-n/ N=1.60-1.78 K=48-138 Project one of contineous works to above a determination of empirical equation on the cautious blasting vibration with Crawler Drill(ø 70-75mm) in long distance. V=41(equation omitted) V=124(equation omitted).

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A Pilot Study of Stiffness Mesurements for Tunnel-Face Materials Using In-hole Seismic Method (인홀 시험을 이용한 터널 막장의 암반강성 측정에 대한 적용성 연구)

  • Mok, Young-Jin;Kim, Young-Su
    • Proceedings of the Korean Geotechical Society Conference
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    • 2005.03a
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    • pp.445-456
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    • 2005
  • The research concentrates on improving the in-hole seismic probe, which has been developed in past five years, to be used in stiffness measurements of tunnel-face materials. The probe was down-sized to be fit in 45-mm diameter holes(or BX) drilled by a jumbo-drill, which is used to drill holes to install explosives for tunneling. Also trigger system was improved by using a down-speeding motor for operating convenience and air packing system was replaced with a set of plate-springs to eliminate supply of compressed air. These modifications are to adjust the probe for the unfavourable environment inside of tunnels and to test without any further drilling cost. The probe and testing procedure were successfully adopted with horizontal holes drilled by a jumbo-drill at a tunnel-face to evaluate the stiffness of rock mass. The measured shear wave velocities can be used to estimate deformation properties of rock mass for tunnel analyses.

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A Study on the Charactdristics of CNC Deep Hole Maching for Marine Part Materials with the Sintered Carbide Gun Drill (초경합금 Gun Drill에 의한 박용 부품 재료의 CNC 심공가공 특성에 관한 연구)

  • 전태옥;심성보
    • Journal of Advanced Marine Engineering and Technology
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    • v.18 no.2
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    • pp.64-74
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    • 1994
  • The gundrill is capable of machining for having large length to diameter ratio in single pass. The techniques of gundrill and gun boring began developing in the late 18th century with the need for more accurate bores in rifle, cannon, machinery part and marine part etc. The main feature of the gun drilling provides a stabilizing cutting force resultant necessary for self guidance of the drill head. A study of the accuracy and surface finish of holes produced would reveal quite useful information regarding the process. The thesis deals with the experimental results obtained during gun drilling on marine part materials for different machining conditions.

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An Empirical Study on Drilling Characteristics of Titanium Carbide Metal Matrix Composites (1) (탄화 티타늄 금속기 복합재의 드릴가공 특성에 대한 경험적 고찰(1))

  • Lee, Jeong-Keun
    • Journal of Powder Materials
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    • v.13 no.6 s.59
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    • pp.445-449
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    • 2006
  • The experimental data from the central composite design runs were utilized for mathematical models far the drilling characteristics containing linear, quadratic and interactive effects of the parameters such as volume fraction of TiC in the composites, drill speed, feed rate and drill diameter. The models were developed via stepwise selection where the insignificant effects were removed using t-test. The models were subjected to optimization of maximizing drill life and satisfying the other constraints.

Standardization of Cautious blasting (정밀발파의 표준화)

  • Huh Ginn
    • Explosives and Blasting
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    • v.8 no.3
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    • pp.3-13
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    • 1990
  • First ot of all, under given condition such as bit gage of 36mm Drill bit with right class of jack-leg-experimental test carried out from two face of Bench, firing of each hole brought 90 degree Angle face and them measured length of Burden and charged ammount of powder as following. $ca=\frac{A}{SW}$ A=Activated Area A=nd i=m S=Peripheral length of charged, room Ca=Rock Coeffiecency d: di=Hole diameter When constructed subway of Seoul in 1980 the blasting works increased complaint of ground vibration, in order to prevent the damage to structures. Some empirical equations were made as follows on condition with Jackleg Drill (Bit Gage 36mm) and within 30 meter distance between blasting site and structures. $V=K(D/W)^{-n}$ N=1.60 - 1.78 K= 48 - 138 Project is one of contineous works to above a determination of empirical equation on the cautious blasting vibration with Crawler Drill (70-75mm) in long distance. $V=41(D/\sqrt[3]{W})^{-1.41}$ $30m\le{D}\le{100m}$ $V=124(D/\sqrt[3]{W})^{-1.66}$ $100m\le{D}\le{285m}$.

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MORDERN METHODS FOR TUNNEL (지하철 터널 굴착공법)

  • Heo, Jin
    • Journal of the Korean Professional Engineers Association
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    • v.14 no.3
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    • pp.9-21
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    • 1981
  • The rationalization for Tunnel Drifting is based on the high productivity which is achievable due to Continuous work with a Jumbo Drill, resulting in a much higher efficiency them the Conventional method of blasting, mucking and supporting services. Large projects of over 4,000m Tunnel Drifting are condidated to justify the use of a Jumbo Drill with a combination of superior explosives, machinery and techniques. During a Tunnel Drifting test, Gulita, Nabit and slurry made by Nitro Nobel were employed with following results. 1, Conditions: a. Granite Rock with Two free face b. Burden (W), 2m c. Diameter of hole, 42mm d. Depth of hole 3.5m e. Hole pitch 0.6m f. Charged Explosive per hole Gelatin Dynamite 4 pieces (112.5${\times}$4ea)+Guuita 5 pieces(110g${\times}$5ea) g. Simal-taneous Detonation h. After the blasting resultant rock size was Less 40% of the 0.3m Lumps. 2. Calculation results W=q/Wn=100cm‥‥‥Burden in simultaneous blasting 0.865kg(7.7ea)/hole ‥‥‥Amount of charge but hole pitch is 1.5W-2W The estimated cost of using a Jumbo Drill for the Construction of a 3,000,000 bbL sub-surface oil storage would be as follows: This calculation is based on the Jumbo Drill advancing 3.6m per blasting cycle. Unit cost/bbL Excavation $3.13 The attached sheet shows ideal Drilling pattern with Burn Cut & Smooth blasting method. In conclusion, it is my opinion that this method will assure safety and save cost and improve our technical know-how.

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