rotary drill

基本解释

The rock stratum drilled by a rotary drill is random distributed and complicated, so it is difficult to define the drilling process.
牙轮钻机钻凿的岩层是随机分布、错综复杂的，因而钻进过程难以定义。
This paper demonstrates developing history of the technique, introduces some new types of percussion-rotary drill and operating technology, and analyzes developing trend.
简要阐述了冲击旋转钻进技术的发展历程，着重介绍了一些冲击器新品种及其相关的钻进新工艺，分析了该项技术的发展趋势。
In rock drilling process with percussion-rotary drill rotating drilling tool bears two toques: dynamic torque which drives drilling tool into rock mass, and resistance torque of rock mass.
前言：在冲击—回转式凿岩机向岩石钻进过程中，旋转中的钻具承受着两种力矩的作用：一是驱动其旋转的动力矩；二是被钻岩石阻止其旋转的阻力矩。

The number of oil and gas rotary drill operates in the metropolitan region is 14 times the national average.
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