• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.4
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• pp.87-93
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• 2021

The mold industry is competitive, and mold should be processed under optimal conditions for efficient processing. However, the cutting conditions of the ball-end mill, which are a major factor in mold processing, are mostly set empirically, and considerable research is required for increasing the tool life and processing accuracy. In this study, a tool dynamometer and an eddy current sensor were used along with NI-DAQ, a data acquisition device, to obtain characteristic values of the cutting force and tool deformation during the ball end-mill machining of inclined surfaces at a machining center. The cutting force and tool deformation were measured in an experiment. It was found that the tool received the greatest cutting force at the end of the machining process, and the deformation of the tool increased rapidly. Furthermore, the cutting force tended to increase with the angle and number of rotations. The deformation increased rapidly during the machining of a 45° inclined surface.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.1
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• pp.75-84
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• 2021

In this study, to evaluate deterioration propagation life and deterioration curve of the shop painted and field re-painted steel bridges, accelerated corrosion tests were carried out on 4 types of heavy-duty painting systems with different surface treatments. The surface treatments prior to painting were examined by hand tool(SSPC SP-2), power tool(SP-3,) or blast cleaning(SP-10) considering shop painting and field re-painting. The paint deterioration curves for each painting system and surface treatment were evaluated based on corrosion propagation from the initial paint defects. From the test results, the paint deterioration life of shop painted and field re-painted system was evaluated and compared by using corrosivity categories and durability performance evaluation of structural steel. The deterioration propagation life of shop and field paint was estimated in 18 to 21 years and 5.3 to 8.0 years with atmospheric corrosion category C4.