• Title/Summary/Keyword: screws

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Three dimensional finite element analysis of static deflections of a machine tool structures (3차원 유한요소 모델링을 통한 공작기계 구조의 정적 변형도 해석)

  • 김현석;이수정;정광섭;이대길
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1993.10a
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    • pp.638-643
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    • 1993
  • The three dimensional finite element models for the basic deflection of linear motion guides and ball screws were developed. Form the comparison of the results calculated by the finite element method with those by the experiment, it was proved that the modeling method might be applied to real machine tool structures. Form the structural analysis of the headstock of the machine tool, it was found that the static stiffness was calculated within 6.5% error

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The Influence of elastic stiffness for a Starting State of Linear Actuator (선형액추에이터의 초기구동에 미치는 탄성계수의 영향)

  • Woo, Byung-Chul;Kang, Do-Hyun;Hong, Do-Kwan
    • Proceedings of the KIEE Conference
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    • 2004.10a
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    • pp.77-79
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    • 2004
  • A typical conventional systems of a linear motion use rack and pinions or ball screws to convert rotary motions from DC servo motors. A linear motor has been used a several field for a MEMS technology and a aircraft carrier. We was studied a transient response of a linear actuator with a damping ratio, spring constant and a pressed power.

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NC 선반의 동적이송오차에 관한 연구

  • 여인완;박철우;이상조
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1996.04a
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    • pp.641-645
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    • 1996
  • Ball screws are used in the feeding system for transmission of driving force. The friction effect between bed and table, which can affect in accuracyin one dimension feeding and describe the dynamic feeding error, could be simplified as a specific model through experiments. The experiments for dynamic feeding errors were performed om tje NC lathe eith a ball screw. The errors in feeding were measured with respect to the variances of feed, spindle speed and motor current for feeding. A rotary encoder and a current sensor were installed with NC lathe.

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Instrumentation in Maxillofacial Surgery: Few Practical Tips

  • Shrotriya, Raghav;Puri, Vinita
    • Archives of Plastic Surgery
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    • v.44 no.6
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    • pp.573-574
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    • 2017
  • When a newly inducted plastic surgery resident embarks on maxillofacial surgery, with drills, screws, plates and burrs, it seems like a new domain altogether. As a new resident, it is truly fascinating as to how such wide variety of bony work is done without scarring over the face. Here we discuss a few practical tips which the author has learned during his surgical sojourn in residency. It is hoped that the readers who are new to maxillofacial surgery, shall find these useful.

Transient Response of a linear actuator with a damping ratio (공진형 선형 액추에이터의 감쇄지수 변화에 따른 과도 응답특성)

  • Woo Byung Chul;Kang Do Hyun
    • Proceedings of the KIEE Conference
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    • summer
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    • pp.1037-1039
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    • 2004
  • A typical conventional systems of a linear motion use rack and pinions or ball screws to convert rotary motions from DC servo motors. A linear motor has been used a several field for a MEMS technology and a aircraft carrier. We was studied a transient response of a linear actuator with a damping ratio, spring constant and a pressed power.

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Investigation in Influence of Screw Design on the MIM Process

  • Gornik, Christian
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 2006.09a
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    • pp.213-214
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    • 2006
  • The results of investigations in screw design for metall injection molding (MIM) will be presented. The consistency of cavity pressure, metering time and MFQ (monitoring of feedstock quality; parameter measured during metering) was chosen to compare different screws. A simulation program was used to optimize the conveying and melting mechanisms in the plastification unit. The theoretical background of this simulation programm will be explained.

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CONSERVATIVE TREATMENT OF BILATERAL CONDYLAR FRACTURE BY A SIMPLIFIED TECHNIQUE OF MAXILLOMANDIBULAR FIXATION (단순악간고정법을 이용한 양측성 하악과두골절의 보존적 치료)

  • Kim, Jong-Pil;Ahn, Sang-Hun;Chang, Heon-Soo;Park, Jae-Bum;Jo, Byung-Woan;Ann, Jye-Jynn
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.17 no.2
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    • pp.171-179
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    • 1995
  • The conservative treatment of the condylar fracture has been used for a long time because of its simplicity, good prognosis and less complication. Traditionally the conservative treatment has been carried out by maxillomandibular fixation using arch bar and wire. But a simplified technique of maxillomandibular fixation introduced here is a procedure that 4 bone screws are placed above the apecies of the maxillary and mandibular canines and then ipsilaterally placed maxillary and mandibular bone screws are linked by a loop of wire each other. This procedure has several advantages compared with the traditional maxillomandibular fixation method. 1) it provides simplicity for the operators. 2) it sustains maxillomandibular fixation more rigidly compared with arch bar technique. 3) it keeps stable maxillomandibular fixation in the region of the anterior teeth so that anterior open bite tendency can be remarkably minimized. 4) it does not injure the periodontal tissue because the teeth are not engaged and causes less discomfort to the patient. 5) it decreases the possibility of operator's AIDS infection through inadvertent skin puncture. 6) it is highly recommended for the patients whose teeth are available for maxillomandibular fixation. The two male patients were diagnosed as bilateral condylar and symphyseal fracture of the mandible. They restored stable occlusion and functional mandibular movement only by a simplified technique of maxillomandibular fixation.

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