What isdeep hole drill bit? What is the problem with deep hole drills?

Deep hole drill refers to the hole depth diameter ratio L/d≥ 5, is a difficult problem in processing, especially the deep hole processing of large aspect ratio. The difficulty lies in the slender tool, poor rigidity, low strength, easy to cause tool skew, heat dissipation and chip removal difficulties. Often larger diameter, taper or hole skew, etc., can not meet the quality requirements.

　　deep hole drill bitProcessing rare method 1, the larger diameter of the deep hole (generally more than 50mm in diameter) should be processed with a set of knives. This method increases the cutting load, thereby improving productivity and increasing material consumption. When the diameter of the cutter is small, the overall welding type is used, and when the diameter is large, the assembly type or adjustable type can be selected. The tool should be equipped with wear-resistant blades for guidance, the material can be cloth bakelite, hard alloy, rolling bearings, etc., blade design should also consider chip separation and chip breaking. Suitable for mass production.

2, with the general machine tool with a long shank twist drill processing. Due to the large axial force during drilling, the symmetry of the two edges of the drill is not easy to grind, the grinding quality of the cross edge of the drill is not easy to guarantee, and the rigidity of the tool holder is poor. Poor, so it is easy to vibrate during processing, and the center line of the hole is easy to skew. The chip accommodation space is unlimited. In order to remove chips and cool the tool, it is necessary to add a drill bit after machining a length (usually 5-10mm). For the main shaft with a long shaft hole, the method of drilling holes from both ends is adopted. Therefore, this deep hole processing method has poor quality, low productivity and high labor intensity. However, due to its simple tool manufacturing and the use of general-purpose equipment, it is widely used in single-piece and small-volume production. The material selection of the standard tool and tooth should be selected according to the load and cutting conditions of each tooth. The base tooth bears a large axial force, the kneading conflict is serious, and the cutting conditions are harsh. Therefore, consideration should be given to high bending strength, good impact resistance YG or YW carbide blade; if the cutting speed is high, should use red hard, high wear resistance YT alloy, guide block selection of high wear resistance YT material.

3. Select the deep hole drill head to process on the public deep hole drill bit. Using deep hole drill to process deep holes can better solve the problems of tool deflection, tool cooling and chip removal in deep hole processing, and significantly improve processing quality and productivity. For deep hole processing machine tools, you can choose a dedicateddeep hole drill bitbed, also can be modified ordinary lathe. The selection standard of the cutter tooth standard is mainly selected according to the cutting load borne by each cutter in the cutting process, and the cutting load is related to the width of the cutter tooth. The cutter width should be determined according to the cutting conditions of each cutter and drill. The size of the dispense diameter. The tooth width distribution should meet three conditions: a. ensure that the eccentricity of the drill tip e =(0.1~0.2)d0.e value is related to the processed material and the diameter of the drill bit, and its size determines the size and direction of the radial resultant force of the drill bit. Reasonable eccentricity makes moderate radial force press on the processed hole wall, which plays a role in stabilizing the drilling, enhancing the guidance and improving the surface quality of the hole. At the same time, the zero cutting of the drill tip is avoided, and the harsh cutting conditions at the drill core are improved. B, A C e F>d0/2 (1~2)mm, I .e. a certain overlapping contact amount is required between the cutter teeth; C, A C- e-F>(1~3)mm, the cutting radial force can always press the guide block and push the guide block forward against the machined hole wall, make full use of the guiding action block of the guide block to ensure the straightness of the drilling.

Some other techniques for deep hole processing 1. The processing method of workpiece rotation and tool feed is used to make the drill bit have self-centering ability to prevent deflection during drilling.

2. After machining a relatively accurate guide hole on the workpiece, so that the drill will not produce deviation at the beginning of cutting.

3. Use pressure to send enough cutting fluid into the cutting area, cool and level the drill bit, and discharge it with the chips.

The above is the deep hole drill bit related content is introduced.