• 산업공학
• /
• 제18권3호
• /
• pp.247-252
• /
• 2005

In the automated production environment in the present days, the minimization of manual operation becomes a very important factor in increasing the efficiency of the production system. The exit burr produced through the milling operation on the edge of workpiece usually requires manual deburring process to enhance the level of precision of the resulting product. So far, researchers have developed various methods to understand the formation of exit burr in cutting process. One method to analytically identify the formation of exit burr was to use the geometrical information of CAD and CAM data used in automated machining. This method, in turn, generated the information resulting from the analysis such as burr type, cutting region, and exit angle. Up to now, the geometrical data were restricted to the single feature and single path. In this paper, a method to deal with the complicated geometric features such as line segment, arc, hole, and spline will be presented and validated using the field data. This method also deals with the complex workpiece shape which is a combination of multiple features. As for the cutting path, multiple tool path is analyzed in order to simulate the real cutting process. All this analysis is combined into a Windows based software and real data are used to validate the program in the conclusion.

• Journal of Korean Neurosurgical Society
• /
• 제60권6호
• /
• pp.717-722
• /
• 2017

Objective : To evaluate the effectiveness and efficacy of delayed burr hole surgery in relation to the reduction of postoperative subdural hematoma (SDH) volume in patients with acute SDH. Methods : We retrospectively analyzed patients with acute SDH who received delayed burr hole surgery at our institute. Age, sex, Glasgow coma scale, maximal SDH thickness, volume of SDH, midline shifts, hounsfield unit (HU), and medical history of anticoagulant agent usage were recorded. Outcome measures were delayed operation day, reduction of SDH volume after operation, and the Glasgow outcome scale (GOS) score at discharge. The patients were divided two groups according to the postoperative reduction of volume of SDH (${\geq}50%$, group A; <50%, group B). We also analyzed variables and differences between two groups. Results : Eighteen patients were available for this analysis. The mean delayed of surgery was $13.9{\pm}7.5$ days. Maximal thickness of SDH was changed from $10.0{\pm}3.5mm$ to $12.2{\pm}3.7mm$. Volume of SDH was changed from $38.7{\pm}28.0mL$ to $42.6{\pm}29.6mL$. Midline shifts were changed from $5.8{\pm}3.3mm$ to $6.6{\pm}3.3mm$. HU were changed from $66.4{\pm}11.2$ to $53.2{\pm}20.6$. Post-operative reduction of SDH volume was $52.1{\pm}21.1%$. Eleven patients (61%) had a discharge GOS score of 1 (good recovery). Ten patients (56%) were enrolled in group A. Midline shifting was greater in group A than in group B ($7.4{\pm}3.3$ vs. $3.0{\pm}2.4mm$; p<0.02). The delay of surgery was shorter for group A than group B ($9.2{\pm}2.3$ vs. $19.8{\pm}7.7$ days; p<0.0008). Conclusion : Among well selected patients, delayed burr hole surgery in patients with acute SDH may be effective for reduction of SDH volume. Further studies will be necessary to establish the effectiveness and safety of delayed burr hole surgery in patients with acute SDH.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2005년도 춘계학술대회 논문집
• /
• pp.159-162
• /
• 2005

The milli-components for electronic and medical device etc. have been manufactured by conventional process. Forming and machining process for those milli-components need tremendous cost and time because products require higher dimensional accuracy than the conventional ones. For instance, conventional mechanical punching process has many drawbacks for applying to high accuracy products. The final radius of hole can be varied and burr which interrupting another procedure is generated. Hydro-mechanical punching process makes possible to reduce amount of burr and obtain the fine shearing surface using the operating fluid. Hydrostatic pressure retards occurrence of initial crack and induces to locate the fracture surface in the middle of sheet to thickness direction. In this paper, Hydro-mechanical punching process is analyzed using finite element method and the effect of hydrostatic pressure is evaluated during punching process. The prediction of fracture is performed adopting the various ductile fracture criteria such as Cockcroft, Brozzo and Oyane's criterion using a user subroutine in ABAQUS explicit.

• International Journal of Precision Engineering and Manufacturing
• /
• 제1권1호
• /
• pp.152-159
• /
• 2000

In piercing operation for small hole in very thin plate, micro burrs are formed. The micro burr is very difficult to remove because the thin plate is to be deformed during deburring and deteriorate accuracy. As a first step to remove the micro burrs effectively, the burr must be measured accurately as much as possible. For most micro burrs are so small as less than 10$\mu\textrm{m}$, it is very difficult to measure. Several methods are reviewed to measure the micro burr formed in piercing operation from very thin plate with thickness less than 0.1mm. Also the effective deburring methods are reviewed. Barreling ultrasonic and chemical deburring methods are performed and the results are compared.

• 한국기계가공학회지
• /
• 제17권1호
• /
• pp.8-15
• /
• 2018

Recently, the manufacturing market for low-cost airlines has led to an increase in aircraft demand. Most processes in the production of these aircrafts are manual such as drilling, sealing, and swaging. A drilling and riveting machine is a numerical-control based equipment that automatically performs drilling, sealing, and swaging operations. The accuracy of the drilled holes and the exit burr length has a significant impact on the quality of the aircraft wing during assembly. This study was conducted to identify the conditions necessary to maintain a uniform quality by controlling the rotation speed of the spindle, which directly affects the hole diameter and the quality of the exit burr.

• 대한기계학회논문집A
• /
• 제28권6호
• /
• pp.867-875
• /
• 2004

In order to inspect burr geometry and hole quality in micro-drilling processes, a cost-effective method using an image processing and shape from focus (SFF) methods on the machine tool is proposed. A CCD camera with a zoom lens and a novel illumination unit is used in this paper. Since the on-machine vision unit is incorporated with the CNC function of the machine tool, direct measurement and condition monitoring of micro-drilling processes are conducted between drilling processes on the machine tool. Stainless steel and hardened tool steel are used as specimens, as well as twist drills made of carbide are used in experiments. Validity of the developed system is confirmed through experiments.

• Journal of Korean Neurosurgical Society
• /
• 제48권4호
• /
• pp.357-359
• /
• 2010

While a delayed intracerebral hemorrhage at the site of a ventricular catheter has occasionally been reported in literature, a delayed hemorrhage caused by venous infarction secondary to ventriculoperitoneal shunting has not been previously reported. In the present case, a 68-year-old woman underwent ventriculoperitoneal shunting through a frontal burr hole, and developed a hemorrhagic transformation of venous infarction on the second postoperative day. This massive venous infarction was caused by bipolar coagulation and occlusion of a large paramedian cortical vein in association with atresia of the rostral superior sagittal sinus. Thus, to eliminate the risk of postoperative venous infarction, technical precautions to avoid damaging surface vessels in a burr hole are required under loupe magnification in ventriculoperitoneal shunting.

• Journal of Korean Neurosurgical Society
• /
• 제53권1호
• /
• pp.59-61
• /
• 2013

Authors report a rare case of acute intracranial subdural and intraventricular hemorrhage that were caused by intracranial hypotension resulted from cerebrospinal fluid leakage through an unidentified dural tear site during spinal surgery. The initial brain computed tomography image showed acute hemorrhages combined with preexisting asymptomatic chronic subdural hemorrhage. One burr hole was made over the right parietal skull to drain intracranial hemorrhages and subsequent drainage of cerebrospinal fluid induced by closure of the durotomy site. Among various methods to treat cerebrospinal fluid leakage through unidentified dural injury site, primary repair and spinal subarachnoid drainage are well known treatment options. The brain imaging study to diagnose intracranial hemorrhage should be taken before selecting the treatment method, especially for spinal subarachnoid drainage. Similar mechanism to its spinal counterpart, cranial cerebrospinal fluid drainage has not been mentioned in previous article and could be another treatment option to seal off an unidentified dural tear in particular case of drainage of intracranial hemorrhage is needed.

• Journal of Korean Neurosurgical Society
• /
• 제45권6호
• /
• pp.397-400
• /
• 2009

This article presents the case of a bilateral chronic subdural hematoma which was contaminated with Klebsiella pneumoniae and resulted in a life-threatening central nervous system infection. After repeated of bilateral burr-hole drainage, the patient became hyperpyrexic and drowsy. Suppuration within the subdural space was suspected and then the patient underwent bilateral fronto-temporo-parietal craniotomies, and pus was evacuated. Its cultures revealed Klebsiella pneumoniae. Intravenous meropenem was given for 6 weeks. He recovered completely. Microorganisms like Klebsiella pneumoniae may directly infect the subdural space with iatrogenic contamination.

• The Korean Journal of Pain
• /
• 제9권2호
• /
• pp.415-418
• /
• 1996

The first reported the neural blockade of ganglion impar for pain control of perineal pain in 1990 by Plancarte and his fellows. they used 6ml of 10 percent phenol. but the point of issues, same as other neurolytics, are that it is impossible to check and control its spreading, so it might be possible to destruct the coccygeal plexus and sacral nerve, and also it has only short action time. Because of these problems, it could be very dangerous to attempt this procedure especially not for relieving the pain on cancer terminal patient, but for the sympathectomy of ganglion impar on the other purpose. We used the RF generator which had the control ability to point out the destructive lesion accurately. inserted We made the small burr hole on the sacrum near the sacrococcygeal junction directly, through the hole, and performed thermocoagulation to the ganglion impar.