Abstract:  When using sodium chloride grain jet to cut biological bone materials， the deformations of the jet beam might cause unexpected damage to the cutting sections of the bone materials， which was not conducive to the later recovery of biological tissue. In order to explore the deformations under the constraints of the side wall during jet cutting and the quality characteristics of the corresponding machined surfaces， a visualization experiment of abrasive water jet cutting was designed. A high-speed camera was used to photograph the abrasive water jet machining processes， the deformations of the jet beam were observed by visual means， and the surface roughness Ra was used to characterize the quality of the machined surfaces. It is found that the jet beam has a diameter-increasing deformation along the cutting feed direction under the joint constraints of the front-end sidewall and the two-side sidewalls， this deformation increases the range and frequency of the reduction in surface roughness along the depth of cut. Finally， through the secondary processing of the change data of surface roughness Ra along the depth of cut， a new idea of establishing the surface roughness prediction model of abrasive water jet cutting material was proposed. 

Key words: abrasive water jet, constrained deformation, surface roughness, visualization experiment

摘要： 利用氯化钠晶粒射流切削生物骨材料时，射流束变形可能会导致骨材料切削断面产生预期之外的损伤，不利于生物组织的后期恢复。为探索射流束切削加工时在边壁约束下产生的变形，以及相应加工表面的质量特点，设计了磨料水射流切削可视化实验。使用高速摄影机拍摄磨料水射流加工过程，利用可视化手段观测射流束变形情况，并使用表面粗糙度Ra表征加工表面质量。研究发现，射流束在前端边壁与两侧边壁共同约束下存在沿切削进给方向的直径增大变形，该变形使加工表面粗糙度沿切深的减小幅度增大及出现频率增多。最后对表面粗糙度Ra沿切割深度的变化数据进行二次处理，提出了一种新的建立磨料水射流切削材料表面粗糙度预测模型的思路。

关键词: 磨料水射流, 约束变形, 表面粗糙度, 可视化实验