Deep-hole drilling is a dedicated deep-hole drilling bits, which can be divided into two types of external chip and chip removal. The biggest drawback of deep drilling is the heat and chip removal difficulties.
Specifically for the processing of deep hole drill. In machinery Deep hole drilling Processing is usually the hole depth and aperture ratio of more than 6 holes called deep hole. Deep hole drilling, cooling and chip removal difficulties, and due to the drill pipe slender and poor rigidity, easy to produce bending and vibration. Generally need to use pressure cooling system to solve the problem of cooling and chip removal.
Deep hole drilling by chip removal method is divided into two types of external chip and chip removal. Outside the chip with a gun drill, deep hole flat drill and deep hole twist drill; within the chip due to the processing system used, divided into BTA deep hole drilling, jet drilling and DF deep hole drilling three. ① gun drill: only a cutting part, the earliest for processing barrel. During drilling, the cutting fluid enters the middle of the drill pipe, is injected into the cutting zone through the small hole in the head of the drill, and is discharged from the V-shaped groove of the drill bit with the swarf. Gun drill suitable for processing aperture 2 ~ 20 mm, hole depth and aperture ratio of greater than 100 deep holes. ② BTA deep hole drilling: cutting fluid from the drill pipe and hole wall into the gap, the pressure of the cutting fluid from the drill pipe hole in the discharge. BTA deep hole drilling for drilling more than 6 mm in aperture, hole depth and aperture ratio of less than 100 deep holes, the production efficiency of more than 3 times higher than the gun drill.
③ jet: a multi-blade deep hole drilling chip, with inner and outer two drill pipe, most of the cutting fluid from the inner and outer drill pipe clearance into the cutting area, and then together with the chip into the inner tube; the other A small part of the cutting fluid enters the inner tube through the crescent-shaped hole at the tail end of the inner tube to generate a spray effect and form a low pressure area, which helps suction the chips. Jet drills do not require a strict cutting fluid seal and are suitable for drilling deep holes with a hole diameter of 18 mm or more and a hole depth of less than 100. ④ DF deep hole drilling: This drill incorporates the advantages of BTA deep hole drilling and jet drilling, using single tube, chip removal by pushing and suction dual role to improve chip removal capacity, drilling more than 8 mm in diameter Deep hole. Gun drill commonly used high-speed steel or carbide. All kinds of deep hole drilling chip evacuation can be based on the size of the welding or mechanical clamping can be indexable cemented carbide blade structure. The guide block on the deep hole drilling guides and centers the center to reduce the deviation of the drilling hole and the vibration during cutting. Deep hole drilling teeth and guide block layout mainly consider the chip and cutting radial force balance. Tool body and drill pipe can be welded or square thread connection.