2 straight shank twist drill rolling groove grinding back process principle When the groove is rolled by the groove rolling and back grinding process, the original four-high rolling mill can still be used, but the section shape of the two blade back sector plates is changed, that is, there is no blade groove. At this time, the role of the two blade-back sector plates is only to fix the drill bit section and adjust the amount of blade-back charge. According to the shape of the parabolic crown and the chisel edge, the s-blade drill tip can be basically divided into three types, namely the high-crown s-blade, low-crown s-blade and low-crown small s-blade type
Features: Because the main cutting edge is short, the torque in machining is small; because the main cutting edge has high strength and small crown curvature, the self-centering and stability are better than the high crown s-edge drill point. The straight main cutting edge of this type of drill is longer. For different rolling cracks, different methods can be adopted to reduce the rolling crack rate. But when the rolling crack aluminum case hand tool set Factory rate is higher than 5%, the groove rolling and back grinding process should be used.
When the groove rolling and back grinding process is used for groove rolling, the rolling mill has a simple pass shape, a reasonable structure, and conforms to the metal flow characteristics, so the occurrence of the above phenomenon can be avoided; at the same time, because the blade band is formed separately, the adjustment difficulty of the four-high rolling mill is also reduced. Especially when the blank is cooled, the narrow and high cutting edge is at the edge of the drill body, the cooling rate is fast, and stress concentration is easy to occur. For example, the rolling crack rate after trial rolling is less than 5%, and the production batch is large, the straight shank twist drill can still be processed by the groove rolling back process.
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