液体火箭发动机等倾角螺旋冷却通道加工技术

将液体火箭发动机燃烧室的冷却通道设计为斜航线(等倾角螺旋线)槽形，可以大幅度改善燃烧室的冷却性能。斜航线冷却槽的槽宽尺寸较小而槽深尺寸较大，所以无法使用棒铣刀铣削、电化学等加工方式。针对这些特点，提出了五轴控制、四轴联动的数控片铣刀铣削加工方法。由于燃烧室外表面的母线轮廓复杂，手工编制数控加工程序难度大。为了解决数控加工程序的编制问题，研究了斜航线的数学模型，开发了自动编程软件系统。使用该系统，可以生成多种母线轮廓回转体外表面上的斜航线数控加工程序。燃烧室收敛—扩张段的母线斜率变化大，加工难度大，是斜航线冷却通道加工的最典型工件。经过理论分析和实际切削实验，研究了针对该类型工件的片铣刀直径选择、铣削方式和方向、刀具调整和起刀点的设置等多项实际的加工方案。采用上述的一系列技术，已经成功地加工了数十个合格工件。经过两年多的实际生产过程应用，验证了所开发的斜航线冷却通道加工方法的正确性和可行性。这些加工技术的研制成功，对其他相似类型零件的加工亦具有参考意义。

Technology of loxodrome coolant channel machining on liquid rocket engine

Disigning coolant channel on the firebox of liquid rocket engine to loxodrome(equal-angle helix) groove can improve firebox coolant capability greatly.Because the width dimension of loxodrome groove is narrow and the depth is deep,some machining methods are incapable,such as end-milling or electrochemistry.According to the peculiarities,a CNC disk-cutter-milling method which is composed of five motion axes with four simultaneously interpolated ones is researched.Because most firebox generatrix is composed of complex curves,it is very difficult to get CNC cutting program with manual means.In order to deal with the problem,the loxodrome mathematics model is studied,and an auto-programming software system is developed.The software system can generate CNC cutting program of loxodrome on many kinds of turned surface.The constriction-distension segment of firebox is the most representative workpiece.The sharp changing of its generatrix slope makes loxodrome milling difficult.With the theory analyzing and practice cutting experiment,some applied techniques,which include milling mode and direction,choosing cutter diameter and cutting start point setting,are developed.Adopting the technology above,tens regular workpiece have been manufacturing.The two-year manufacture practice has confirmed the validity and feasibility of developed loxodrome coolant channel milling method.The developed technology is also worth to be referenced to other similar workpiece.