硬质合金内冷钻头三维参数化建模研究
Three？？Dimensional Parametric Modeling of Carbide Internal Cooling Aiguille

针对硬质合金内冷钻头结构复杂、尺寸多、建模难度大的问题,进行三维参数化建模,在UG软件中建立了三维参数化设计系统。按照设计参数,首先将端刃截形沿螺旋线扫掠,生成内冷钻头的螺旋槽模型。其次,与传统麻花钻的钻尖仅包含单曲面或双曲面不同,内冷钻头的钻尖包含了第一后刀面、第二后刀面等多个曲面;根据端刃第一后角、第二后角、Gash角等具体参数,建立了第一后刀面、第二后刀面、Gash面等钻尖曲面的模型。在细节处理部分,由于退刀槽由光滑曲面过渡衔接而成,难以通过数学模型的方式进行建模,因此利用UG强大的曲面造型功能,使用桥接曲线、网格曲面等操作,生成了过渡自然的退刀槽模型。运行实例表明,硬质合金内冷钻头三维参数化设计系统能够根据设计需要快速完成三维模型的建立,生成的模型准确描述了螺旋角、端刃后角、Gash角等关键参数,在退刀槽等细节部位过渡自然,实现了硬质合金内冷钻头三维模型的精确表达。
Aiming at complex structure and difficult parametric modeling of carbide internal cooling aiguille, a system for three？？dimensional parametric design is developed in Unigraphics NX (UG). According to the design parameters, a mathematical model of the cross section of the end cutting edge is established. Then the cross section is swept along the helical curve to construct the helical groove model in UG. Differing from the point of the normal twist drill, which includes only single curved surface or double curved surface, the point of carbide internal cooling aiguille consists of several surfaces, like first flank face and second flank face, so their corresponding three？？dimensional models are set up in UG with such parameters as first clearance angle, second clearance angle, and gash angle of this point. The detailed structure undercut is composed of a series of smooth surfaces, the undercut model can be created by a few UG operations, such as bridge curve, through curve mesh, etc. It is found that this three？？dimensional model of carbide internal cooling aiguille is sufficiently precise, and the key parameters of carbide internal cooling aiguille, such as helix angle, clearance angle and Gash angle, can be described accurately with smooth transition at the undercut in the design system