In the early 1970s, drilling machines were controlled by common relays in the world. For example, the mega50 of Eldorado company of the United States, t30-3-250 of TBT company of Germany, b4-h30-c / L of Nagel company, and DEG type drilling machines of Japan's Shenqi advanced Seiko production Institute were all controlled by relays. < br style = "list style type: none;" / > folding was gradually applied to deep hole drilling machines in the late 1980s due to the emergence of numerical control technology, especially after 90 years. For example, in the ML series deep hole drilling machine launched by TBT company in the early 1990s, in addition to the fact that the feed system of the ML series deep hole drilling machine is changed from the mechanical stepless transmission to the AC servo motor driven ball screw pair, and the sliding table guide rail adopts the rolling linear guide rail. In order to ensure high-speed rotation and stable accuracy, the drill pipe box drive is changed from the variable frequency drive driven by the exchange belt pulley and belt, and the two speed motor into the variable frequency stepless speed regulation Motor to motorized spindle drive, for drilling small hole deep hole drilling machine and improve the horizontal quality of deep hole drilling machine to create favorable conditions. In order to process oblique holes, vertical holes or parallel holes on some parts with cross or arbitrary angle, or with the machining part center line at a certain angle, various countries specially develop a variety of special deep hole drilling machines. For example, it is specially used for machining oil holes on crankshaft, inclined oil holes on connecting rod, parallel holes and multiple radial discharge holes of feed machine upper die. It is especially suitable for bw250-kw deep hole drilling machine for crankshaft oil hole of large and medium-sized trucks. They all have X, y, Z, w four axis CNC. The first flexible crankshaft machining center was designed and manufactured in 2000, which can process all oil holes on different crankshafts of 2-12 cylinders. The special deep hole drilling machine with six equal parts and six spindles for processing six holes on the same workpiece is manufactured by mollart company. There are as many as 36000 holes in the workpiece. It's all controlled by a numerical control system. < br style = "list style type: none;" / > later, 3D drilling came into being. With the development of society, drilling machines are also constantly improving.