INVESTIGATION ON HARDENED STEEL MILLING WITH MICRO-END MILL

Tool wear and breakage of the micro-milling tool is an important problem for high speed machining of hardened steel die and mould. Dry milling of S136 hardened steel is carried out using TiA1N coated carbide micro-end mill (Ф2 mm). The effect of cutting speed, feed per tooth and radial depth of cut on cutting force is analyzed. Cutting parameters adapting to dry machining and strategy optimized for higher rate of material removal with lower cutting force are attained. Results of SEM observation show that the main failure patterns of micro-end mill are breakage of tool tip, wear and drop-off of surface coating, micro-chipping, and breakage of flank.

基于修复理念的单侧游离腓骨肌皮瓣同期重建上下颌骨缺损

目的:探讨单侧游离腓骨肌皮瓣修复重建同侧上下颌骨缺损为义齿修复奠定基础方法的可行性。方法:回顾性研究2016年1月至2017年6月期间就诊于福建医科大学附属协和医院的患者并采用单侧游离腓骨肌皮瓣同期重建上下颌骨缺损的病例信息,全面分析患者的基本信息、临床特征、病例诊断、治疗方式以及术后并发症等相关信息。结果:4位患者在此期间应用单侧游离腓骨肌皮瓣同期重建上下颌骨缺损,其中3位患者病理诊断为鳞状细胞癌,另1位患者病理诊断为骨化性纤维瘤;四位患者颌骨缺损范围均不同程度涉及同侧上下颌尖牙远中区域,术中血管吻合均采用腓骨动脉与颌外动脉吻合、腓骨静脉与颈外静脉吻合的方式,平均手术时长7小时,皮瓣最大制取面积约10cm×6cm。术后1例患者皮瓣发生静脉血栓,其余患者皮瓣存活良好,所有患者术后张口度与术前无明显变化。所有患者在随访期间腓骨供区愈合良好,未见明显并发症。结论:采用单侧游离腓骨肌皮瓣同期重建同侧上下颌骨缺损是一种相对可行的外科修复重建手段,有利于义齿修复。