The so-called deep hole machining is a hole with a ratio of the length of the hole to the diameter of the hole greater than 6.
In deep hole machining, in most cases, the depth-to-diameter ratio of deep holes is L/d ≥ 100.
Such as cylinder holes, axial oil holes of shafts, hollow spindle holes and hydraulic valve holes, etc.
Some of these holes require high machining accuracy and surface quality, and some of the processed materials have poor machinability, which often become a major problem in production.
