BTA 드릴의 가공정밀도를 위한 가공방법개선에 관한 연구

A Study on Drilling Process of Fuel Common Rail for BTA Drill

The BTA drilling has not shown much progress in its technology since its development by Beisner in 1942, which is currently used for deep hole drilling among several drilling technologies, but its cutting ability is improving by the development and adoption of cemented carbide tip and coating of tool surface, also the research is recently progressing to apply ceramics on the guide pad. The machining by BTA drill performs unique distribution of cutting power and chip discharging by high-pressure coolant supply based on the self-guiding method of the pad. As its characteristic is superior to other drilling methods in deep hole drilling of big length/diameter ratio as well, its applications are now being expanded for hole drilling of big molds, machining of tube sheet, which is a core part of heat exchanger, machining of various parts for automobile, and so on, which is equipped with modified general machine or dedicated equipment for the production of various kinds of parts. However, the biggest problem currently appearing in the deep hole drilling of big length/diameter ratio is the degree of tolerance, such as precision of diameter (bending, hole enlargement), concentricity, parallelism, cylindricity, surface roughness, and so on. The causes of such troubles are assembly error of BTA drill machining system, unbalance of cutting power due to the shapes of work pieces and tools, etc., which cannot satisfy the quality level requested.