三牙轮钻头是石油钻井的重要工具，是否其性能的好坏将直接影响质量的钻进，钻进效率，降低钻井成本。在传统的三牙轮钻头设计是基于实践经验并结合方法的试验和错误、 重复的设计和计算，所以设计精度低、 周期长，很难提高设计质量。每个计算的设计也只能是一点，但与低效率。因此，制定一套三牙轮钻头钻头 CAD 系统，实现参数化绘图的三牙轮钻头是十分必要的。

系统的总体设计。三牙轮钻的参数化绘图系统采用模块化的编程方法;整个系统分为四个功能模块: 用户界面管理模块、 钻头的牙表面结构设计模块、 数据库管理模块和参数化绘图模块。性能的辊锥钻头设计的用户界面使用 VBA，嵌入在 AutoCAD 中，实现第二个工具的开发。用户通过用户接口模块输入相关参数的三个锥形钻头设计，实现人机通信。钻头牙齿三锥位三位数据的复杂的计算设计理论设计了结构设计模块的主要功能。数据库管理模块被由 Access 2003 作为一种数据从数据库的建立。

Three cone bit is the important tool in oil drilling, whether its performance is good or bad will directly affect the quality of drilling, drilling efficiency and drilling cost. Three cone bit's design in the traditional is based on practical experience and combined with the method of trial and error, repeated design and calculation, so the accuracy of design is low, the cycle is long and it is difficult to improve the quality of design. And the design of each calculation can only be a bit and with low efficiency. Therefore, to develop a set of three teeth wheel drill bit CAD system and realize parametric drawing of three cone bit are very necessary.

Total design of the system. The parametric drawing system of three teeth wheel drill adopts the modular programming method; the whole system is divided into four functional modules: user interface management module, the bit of tooth surface structure design module, database management module and parametric drawing module. The performance of roller cone bit design of user interface use VBA, which is embedded in AutoCAD, to realize second tools development. The user through the user interface module input relevant parameters of three cone bit design to realize the man-machine communication. The main function of the bit teeth structure design module is designed according to the theory of three cone bit three bit data for the design of complex calculations. Database management module is composed of Access 2003 as a data from the establishment of the database.