생체용 마그네슘 합금은 전연성 부족과 열에 의한 팽창률 변화가 심하여 2mm 이하의 판재를 만드는 것이 매우 어려움 문제이다. 이를 해결하기 위해 압연 방식, 세이퍼 방식, 밀링 방식 등의 다양한 방법이 존재할 수 있다. 압연 방식을 적용하여 실험을 진행하였으나 Mg 합금은 전연성, 취성의 문제로 인해 파괴되는 현상이 발생하였다. 그리고 세이퍼 방식은 가공시 충격이 발생하는 단속절삭이기 때문에 표면에 자국이 남게 되고 시험편이 휘어지는 현상이 발생하는 문제가 발생하였다. 최종적으로 밀링 방식으로 전환하여 가공실험을 수행해 본 결과 매우 만족할 만한 결과값을 얻게 되었고, 이 결과는 절삭조건을 절삭회전수 1000rpm, 이송속도 127mm/rev, 절삭깊이 0.5mm로 엔드밀 사용하여 가공하였을 때 Ra = 0.44㎛의 표면거칠기값을 얻게 되었다. 본 논문에서는 생체 마그네슘 합금재료로 미소판재를 가공하였을 때 매우 좋은 표면을 유지하며 2mm 이하의 미소 두께를 지속적으로 가공이 가능하도록 하였으며, 다양한 절삭조건, 2날과 4날 엔드밀 날수 변화 등을 통해 최적의 가공조건을 알아보는 실험을 진행하였다.

Currently, due to the development of technology, the industry is proceeding with the development of advanced materials with high performance such as light weight, heat resistance and electric conductivity. Carbon Fiber Reinforced Plastics (CFRP) is an excellent material with high heat resistance, high strength and thermal shock resistance. In order to obtain excellent hole shape in CFRP drilling, we compared the modified drill shape and the conventional carbide drill. On the other hand, we determine the proper helix angle by observing the CFRP surface according to the helix angle at the trimming of the end mill proceeding after the hole machining.

The development of machining technology has coincided with the recent development of a diverse amount of materials and tools. The developed materials largely consist of hardened steel for vehicle and the mechanical industry. The machining of the hardened steel is performed in a lathe and many kind of machining centers, but it is difficult to machine because its hardness is the most difficult-to-cut materials. Hard-turning is a kind of machining process which omits the final grinding process and replaces it with a single accurate cutting process. In this paper, the turning of SKD 11(HRC 58) was performed using the CBN tool in order to recognize the optimum process conditions. The cutting force, tool life and wear, surface roughness were measured. Examining the machining characteristics when cutting of high hardened steel, low cutting speed and high conveying speed were identified to be effective in cutting conditions of SKD 11. Tool life was most effective in the conditions with 65m/min of cutting speed and 0.193mm/rev of feedrate and approximately 0.5um of very good surface profile was acquired at 0.079mm/rev of feedrate. Therefore, when cutting with Low CBN tool, it could be considered to be sufficient in reducing the steps of precision machining or replacing the polishing

Excavator working in the quarry and junkyard, is very difficult to move the things in the truck, because the position of the cab is low, eyesight is not visible. The cab visibility, safety and ease of operation is obtained by the development of the cab lifting system moving the position. To apply cab lifting system on the existing excavator, development of new sub-frame is positively necessary. In this study, the sub-frame, which is suitable for its main function, is manufactured and is verified through hardness test, finite element analysis and endurance test.

In commercial vehicle, sub-frame which equipped in main frame supporting dump deck and oil tanker. This is the main structure for all equipment which including joint function. Sub-frame is made by welding process, this susceptible to deform and crack by its longitudinal size. Also various kind of sub-frame make it difficult to standardization in manufacturing process and exclusive jig is not adapted yet. Frame size is over 6~8m and weight is more than 300kg this make re-work more difficult. If manufacturing company made precise sub-frame, this is not only convenient for customers but also save the company money by reducing the working time. In this study manufacture the sub-frame be suitable for its main function and develop exclusive welding jig for obtain checking fixture function as well.

The concrete mixer truck which is in charge of raw materials in civil engineering construction of the concrete loading, transport, placement, is used 6m3, 7m3 class in domestic(Korea). But in the case of the international construction fields are utilized 9m3 or above class because of the large-scale engineering and construction circumstances. In this paper, to develop a large 9m3 class mixer drum and the mixer drum in order to complement the technical and discharge that is responsible for stirring the blades by applying optimal design through implementation of the optimal shape of the concrete in the drum maintenance and placement of high-quality effects on increasing discharge such as advanced conventional drum mixer is to secure and differentiated technology. Large, heavy weight in development and uphold the drum mixer vehicle sub-frame is required to settle the design of the existing class mixer drum frames per 6m3 changed to account for changes in slope and length using CATIA V5 3D modeling work was performed.

The purpose of this study is to investigate cutting characteristics and wear behavior in SCM440 steel with different cutting tools, CBN(Cubic Boron Nitride) and coated CBN. During the test coated CBN toolespecially with TiAlN showed better wear resistance behavior than orginal CBN tools. In the interruptedcutting condition, axial groove affected tool surface with impact force during the turning operation. Foradvantageous turning parameter in the interrupted process it is recommendable that lower speed. Also surface roughness showed better behavior in the coated CBN tool conditions than normal CBN conditions. Mainly this is caused by reduced friction between material and tool surface with coated layer.

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.

The swivel joint is an important part in hydraulic machine. The analysis on the material was made using the EDAX method to localize the swivel joint. Also, the modeling and design drawing were finalized with application of 3 dimensional measurement and structure analysis. The prototype product based on design drawing was made with cutting and grinding process. No abnormalities were found in the prototype product through the durability test and measurement. The localized swivel joint with light weight, price reduction and diversification was developed in this study.