• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2007년도 춘계학술대회 논문집
• /
• pp.383-386
• /
• 2007

In this study, the analysis was carried out for Electrical Discharge Machining (EDM) characteristics of the Cu electrodes by LIGA process. The shape of electrodes has 324 pins for the cavity of BGA(Ball Grid Array) type test socket mold. BGA test sockets are used in the inspection process of the semi-conductor I.C chip manufacturing. In the work, the machining performance for EDM of the electrodes was analyzed on dimensional accuracy and wear rate. The dimensional accuracy was measured for dimension of the pins, pitch size between the pins and the roundness of corner edge using optical measuring machine.

• 한국생산제조학회지
• /
• 제9권4호
• /
• pp.117-122
• /
• 2000

This paper presents an indirect compensation of thermal errors during machining , in which thermal error is modelled as a linear regression of temperatures measured at 4 specified positions. In this regression model, weighting coefficients of the measured temperatures were estimated by using the least square method. The grinding test with compensation , after 4 -hour warning-up operation before the test, showed that the maximum machining error of the work pieces was reduced to 12${\mu}{\textrm}{m}$ while it measured by 28${\mu}{\textrm}{m}$ without compensation . Furthermore the standard deviation of machining errors was also reduced from 8${\mu}{\textrm}{m}$ to 2${\mu}{\textrm}{m}$.

• 한국공작기계학회:학술대회논문집
• /
• 한국공작기계학회 2000년도 춘계학술대회논문집 - 한국공작기계학회
• /
• pp.673-678
• /
• 2000

This paper presents an indirect compensation of thermal errors during machining, in which thermal error is modeled as a linear regression of temperatures measured at 4 specified positions. In this regression model, weighting coefficients of the measured temperatures were estimated by using the least square method. The grinding test with compensation, after 4-hour warming-up operation before the test, showed that the maximum machining error of the work pieces was reduced to 12${\mu}{\textrm}{m}$ while it measured 28${\mu}{\textrm}{m}$ without compensation. Furthermore the standard deviation of machining errors was also reduced from 8${\mu}{\textrm}{m}$ to 2${\mu}{\textrm}{m}$.

• 한국정밀공학회지
• /
• 제13권1호
• /
• pp.123-130
• /
• 1996

The procedure on the design of a new tungsten cabide throw-away cutting tool system for deep grooving or cut-off machining is suggested. For relieving the maximum stress level at the corner radius of the blade holder, the finite element method is used. Also the pulling test device is proposed for measuring the holding force of the insert between the blade holder and the insert considering the materials in contact and configuration parameters of the holder.

• 한국공작기계학회:학술대회논문집
• /
• 한국공작기계학회 2005년도 춘계학술대회 논문집
• /
• pp.473-476
• /
• 2005

Today's manufacturing industry is facing challenges from advanced difficult-to-machine materials (WC-Co alloys, ceramics, and composites), stringent design requirements (high precision, complex shapes, and high surface quality), and machining costs. Advanced materials play an increasingly important role in modem manufacturing industries, especially, in aircraft, automobile, tool, die and mold making industries. The greatly-improved thermal, chemical, and mechanical properties of the material (such as improved strength, heat resistance, wear resistance, and corrosion resistance), while having yielded enormous economic benefits to manufacturing industries through improved product performance and product design, are making traditional machining processes unable to machine them or unable to machine them economically. In this paper, mechanical characteristic evaluation test of fine powder type WC-Co alloy was accomplished to obtain clear data for miniaturized special die parts machining with high reliability and high quality.

• 한국군사과학기술학회지
• /
• 제15권3호
• /
• pp.315-321
• /
• 2012

In the study, corrosion characteristics of AZ31 magnesium alloy under various environments exposed during machining(immersion in cutting oil, 5 % cutting oil aqueous solution and distilled water & contact with dissimilar metals, SPC4 and A5052-H32) were investigated. A corrosion test was performed AZ31 magnesium alloy was immersed in each electrolyte solution after contacting with each dissimilar metals, and the results were observed by an electron microscope. In immersion tests, corrosion of AZ31 magnesium alloy showed to be in the sequence of distilled water> 5 % cutting oil aqueous solution> cutting oil> air, and in the test of contact with dissimilar metals, corrosion showed to be in the sequence of SPC4> A5052-H32> AZ31. It can be concluded that to prevent corrosion during machining, AZ31 magnesium alloy must prevent contacting water and use magnesium alloy for raw material of Jig & Fixture.

• 한국기계가공학회지
• /
• 제11권1호
• /
• pp.13-19
• /
• 2012

In this study, ultrasonic vibration tool designed and made by using FEM analysis. And machining test was carried out in various machining conditions using ultrasonic vibration capable CNC machine. For work material, alumina ceramic ($Al_2O_3$) was used while for tool material diamond electroplated grinding wheel was used. To evaluate ultrasonic vibration effect, grinding test was performed with and without ultrasonic vibration in same machining condition. In ultrasonic mode, ultrasonic vibration of 20kHz was generated by HSK 63 ultrasonic actuator. The two grinding speeds, 1.67m/s and 3.35m/s, were applied. On the other hand, grinding forces were measured by KISTLER dynamometer.

• 한국기계가공학회지
• /
• 제10권1호
• /
• pp.54-61
• /
• 2011

Ball screw systems are largely used in industry for motion control and motor applications. But the problem of noise, which really perplexes us, is highly correlated with the quality in ball screw systems all the way. In this paper, machining process parameters were evaluated in respects of technique, business, produce and quality to verify which impact influences the noise most. In order to adjust and compare, two comparison groups were set with the present parameters bench mark. Different ball screws were produced as specimens for the noise tests. Through comparing the noise performance of different parameters in the machining process respectively, a group of optimized machining process parameters were obtained. Another noise test was proceeded to know how noise performance was improved by optimizing the machining process parameters. At last, surface roughness tests have been done to know how surface roughness improved by optimization. The improvement of surface roughness is the main factor influences the noise performances.

• 반도체디스플레이기술학회지
• /
• 제18권3호
• /
• pp.133-139
• /
• 2019

The utilizations of ceramics in the modern industries are increasing due to the desirable combinations of electrical, mechanical and physical properties found in ceramics. Ceramic materials are brittle, hard, strong in compression, weak in shearing and tension which is prone to affect the defects such as scratch, crack and breakage during the machining. Generally, the defects of the ceramic machining are generated from the structural vibrations of the machine. In this study, the dynamic characteristics of a machining center for ceramic machining were investigated to analyze the structural vibrations for the improved stability. Frequency response test and computer simulation have been conducted for the analysis and the design improvement. The improved design is suggested to suppress vibrations for the higher stability of the machine and further to reduce vibrations. And the result shows that simple design alterations without any change of major parts of the machine can reduce the vibration of the machine effectively.

• 한국산학기술학회논문지
• /
• 제17권2호
• /
• pp.642-648
• /
• 2016

3차원 솔리드모델링이 일반화되면서 이를 이용한 여러 응용이 가능해졌으며, 가장 대표적인 응용분야인 CAM과의 통합을 위한 다양한 연구가 진행되어왔다. 그 결과 설계된 부품의 CAD모델로부터 실제가공에 필요한 특징형상을 자동으로 인식하는 기술들이 개발되었다. 하지만 이러한 방법으로 인식된 특징형상들을 이용하여 절삭가공순서 등을 자동으로 생성하기 위해서는 고려하여야 할 가공순서의 조합의 수가 너무 많아 이를 구현하기에는 현실적으로 문제가 발생한다. 이에 본 연구에서는 절삭가공에 관련된 규칙을 수집하고 이를 이용하여 특징형상 간 가공우선순위를 적용함으로써 고려하여할 조합의 수를 대폭 감소시키고, 이들 조합으로부터 효율성을 최대화 하는 가공순서를 결정하는 방법을 제안하였다. 또한 항공기 부품에 대한 테스트를 통하여 20개의 특징형상으로부터 가공시간이 적은 가공순서를 자동으로 생성할 수 있었다.