• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.2
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• pp.165-170
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• 2012

The resin bonded diamond wheel is used to grind the difficult-to-cut materials. Traditionally, the resin bonded diamond wheel is manufactured without any pores due to the characteristics of resin bond. In this study, two porous resin bonded diamond wheel were made and the grinding characteristics were compared with traditional nonporous ones. The experimental results indicate that the porous resin bond diamond wheel require less grinding forces and powers.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.3
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• pp.22-28
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• 2022

In the semiconductor and display component industries, the use of ceramic materials, which are high-strength materials, is increasing for ensuring durability and wear resistance. Among them, alumina materials are used increasingly. Alumina materials are extremely difficult to process because of their high strength; as such, research and development in the area of mineral material processing is being promoted actively to improve their processing. In this study, the processability of an electrodeposition tool is investigated using the electrodeposition method to smoothly process alumina materials. Furthermore, processing is conducted under various processing conditions, such as spindle speed, feed speed, and depth of cut. In addition, the processing characteristics of the workpiece are analyzed based on the tooling.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.2
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• pp.171-176
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• 2012

So far, carbide insert production technology was carried out using a diamond grinding wheel. This production technology has problem that raise production costs and decrease in productivity. The SIDE PRESS method to solve this problem have been developed. In this paper, the machining characteristics of lateral chip breaker turning inserts produced by the SIDE PRESS method was studied. The cutting force and the resulting surface roughness were measured at various cutting conditions. The experimental results indicate that the chip breaker inserts of three-dimensional geometry is the best cutting performance.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.3
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• pp.66-71
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• 2016

Reducing the wafer breakage rate and sawing thinner wafers will decrease the cost of solar cells. This study was carried out in order to identify ways to achieve this goal. In this study, the cutting force characteristics using an ingot tilting-type diamond multi wire-sawing machine were analyzed. The cutting force was analyzed while varying the tilting angles and wire speed. The obtained data were analyzed by classifying the tangential cutting force and the normal cutting force. In this cutting force experiment, the difference between the forces was confirmed; it was found that it rises with increasing the tilting angles and decreases when the wire speed elevates. The resulting value can be utilized as basic data for the determination of an ideal cutting recipe.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.2
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• pp.73-78
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• 2011

The existent cutting insert have occupied most product of grinding style, because it has a problem of accuracy and manufacturing process. The product has a concept but development is difficult, because grinding and manufacturing by press are impossible. But by development and stabilization of a technology, preference of non-ground insert increases gradually. And then insert that grinding is impossible is developed availably as non-ground product by using developed equipment and software. In this paper reports some experimental results on the machining performance of non-ground Cutting inserts. Three kinds of Cutting inserts were manufactured without using grinding process. Machining experiments were carried out to compare the machining performance of non-ground inserts with that of ground ones. The experimental results indicate that the cutting forces and tool wear and surface roughnesses of machined surface of both ground and non-ground inserts are comparable.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.3
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• pp.105-110
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• 2020

Alumina, a typical ceramic material used for semiconductors and display parts, is the subject of research and development efforts for mineral material processing. Alumina is extremely difficult to process since it is brittleness to either fine ceramics material. We have studied the shape of diamond particles and their use in machinability for alumina processing. Our study was carried out under various processing conditions, including cutting speed, table speed, and the surface roughness of the work piece. We also analyzed the wear characteristics of the tool by total cutting.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.283-287
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• 1997

공작기계의 가공정도는 공작기계의 운동기구가 가지고 있는 기하오차와 절작작업시 발생하는 진동, 열,절삭력에 의해서 공작기계의 구조계,주축계,이송계의 변형에 의해서 직접적인 영향을 받는다. 또 가공정도는 제품의 정밀도 및 품질에 직접적인 영향을 미치기 때문에 가공정도를 향상시키기 위한 방법으로 공작기계의 오차를 측정/해석하는 방법이 연구되고 있다. 일반적으로,공작기계의 오차는 Quasi-static 오차와 Dynamic오차로 구분할수 있다. Dynamic 오차는 기계의 진동,채터 및 스핀들의 진동에 의해서만 발생하는 오차이며,Quasi-static 오차는 공작기계 구성요소인 안내면,칼럼,볼스크류등의 기하오차와 온도변화에 의한 열변형오차에 의해서 발생한다. 특히,공작기계 및 절삭가공중에 발생하는 열원에 의한 열변형 오차는 공작기계의 기하오차에 비해서 가공정도에 큰 영향을 미치며[1,2],발생오차의 약 40~70% 정도가열변형 오차에 기인한 것으로 알려져 있다[1]. 실제 많은 실험결과를 볼 때 CNC공작기계이 경우는 열변형에 의한 오차는 기하오차에 비해서 매우 크게 나타났다. 이러한 열변형 오차는 공작기계 주위 온도와 공작기계 구성요소(칼럼,이송유니크,스핀들유니트)의 비선형적인 온도 특성에 의해서 주로 발생하고, Time-variant특성을 가지고 있기 때문에 작업중에 발생하는 온도특성에 따른 열변형 오차를 최소화 할 수 있는 방법이 필요하다. 스핀들유니트는 냉각방식을 사용하여 온도변화를 줄이고 있으나 반복적인 작업과 스핀들의 고속회전으로 인해서 복합 적인 온도변화를 발생시킨다. 또, 볼스크류의 지지방식이 양쪽 고정단 형태이기 때문에 조립시 예압(pre-load)을 주어서 열팽창을 보상하고 있으나 공작기계의 반복적인 이송으로 인해서 발생하는 온도변화에 의한 열오차를 보상하는데는 어려움이 있다.됩니다. 생리적 저항력이 없는 어린이들은 이러한 공해와 생활조건의 제일희생자가 되는 것입니다. 엄마들이 "얘는 감기, 비염, 편도선을 달고 삽니다...." "얘는 코감기, 목감기 번갈아 가면서 하도 앓고 있어서 양약율 중지하고 현재 한약을 먹고 있습니다." 이러한 역경은 극복할 수 있는가\ulcorner 질병의 메카니즘은 어떻게 작용되는가\ulcorner 등등을 육미회 센타에서 체험한 사례를 가지고 말씀드리고자 합니다..ell layer (PCL)와 glia에 SOD-1이 강하게 염색되었다. APT 병용 투여로 상당수의 경련이 일어나지 않은 흰쥐는 해마의 DG에 FRA가 경미하게 염색되었고, PCL에 SOD-1도 경미하게 나타났으나, 경련이 나타난 쥐에서는 KA만을 투여한 흰쥐와 구별되지 않았다. 이상의 APT의 항산화 효과는 KA로 인한 뇌세포 변성 개선에 중요한 인자로 작용할 것으로 사료되나, 보다 명확한 APT의 기전을 검색하고 직접 임상에 응응하기 위하여는 보다 다양한 실험 조건이 보완되어야 찰 것으로 생각된다. 항우울약들의 항혈소판작용은 PKC-기질인 41-43 kD와 20 kD의 인산화를 억제함에 기인되는 것으로 사료된다.다. 것으로 사료된다.다.바와 같이 MCl에서 작은 Dv 값을 갖는데, 이것은 CdCl$_{4}$$^{2-}$ 착이온을 형성하거나 ZnCl$_{4}$$^{2-}$ , ZnCl$_{3}$$^{-}$같은 이온과 MgCl$^{+}$, MgCl$_{2}$같은 이온종을 형성하기 때문인것 같다. 한편 어떠한 용리액에서던지 NH$_{4}$$^{+}$의 경우 Dv값이 제일 작았다. 바. 본 연구