The requirements of high quality machined surface as well as demand of enhanced contact time of cutting tools drive towards adopting multilayer coated carbide inserts. The industry requires higher productivity, hence ...The requirements of high quality machined surface as well as demand of enhanced contact time of cutting tools drive towards adopting multilayer coated carbide inserts. The industry requires higher productivity, hence higher machining parameters need to be used in order to meet the industry requirements. The alloy steel material used to fabricate machine parts consists of alloying elements like nickel, chromium and molybdenum difficult to machine, since the cutting tool fails by high tool wear, if we use uncoated carbide inserts to machine alloy steels. Hence in the present research work it is intended to use tungsten carbide inserts coated with different coatings for the experiments. The turning experiments were carried out using different grades of uncoated and coated carbide inserts of identical tool signature. The cutting speed selected for the experiments was 100 to 500 m/min in steps of 100 m/min, and the feed per revolution was 0.1 mm to 0.4 mm in step of 0.1 mm. The experimentation was carried out following ISO3685 standards. The results of the experiments revealed that the surface roughness measured was the least at cutting speed 500 m/min and feed per revolution of 0.1 mm, however the chip breaking found better when the feed used was greater than 0.2 mm/revolution.展开更多
文摘The requirements of high quality machined surface as well as demand of enhanced contact time of cutting tools drive towards adopting multilayer coated carbide inserts. The industry requires higher productivity, hence higher machining parameters need to be used in order to meet the industry requirements. The alloy steel material used to fabricate machine parts consists of alloying elements like nickel, chromium and molybdenum difficult to machine, since the cutting tool fails by high tool wear, if we use uncoated carbide inserts to machine alloy steels. Hence in the present research work it is intended to use tungsten carbide inserts coated with different coatings for the experiments. The turning experiments were carried out using different grades of uncoated and coated carbide inserts of identical tool signature. The cutting speed selected for the experiments was 100 to 500 m/min in steps of 100 m/min, and the feed per revolution was 0.1 mm to 0.4 mm in step of 0.1 mm. The experimentation was carried out following ISO3685 standards. The results of the experiments revealed that the surface roughness measured was the least at cutting speed 500 m/min and feed per revolution of 0.1 mm, however the chip breaking found better when the feed used was greater than 0.2 mm/revolution.
文摘目的 探讨不同吻合术在行腹腔镜远端胃癌根治术(laparoscopic distal radical gastrectomy,LDRG)患者中的应用效果。方法 选取2020年3月—2022年3月于福鼎市医院行LDRG的58例患者。采用随机数字表法分为观察组29例与对照组29例。对照组术后接受Roux-en-Y吻合术,观察组患者术后接受非离断Roux-en-Y吻合术。比较2组患者手术指标、术后并发症发生率以及患者生活质量。结果 观察组排气时间短于对照组(P<0.05),2组手术时间、吻合时间、住院时间、术中出血量、淋巴结清扫数目比较,差异无统计学意义(P>0.05)。观察组患者术后6个月ROUX淤滞综合征(ROUX stasis syndrome,RSS)发生率为3.45%,低于对照组的27.59%(P<0.05);2组吻合口出血、胃食管反流、吻合口溃疡、吻合口瘘、腹腔感染发生率比较,差异无统计学意义(P>0.05)。术后2组患者各项健康调查简表(the MOS item short from health survey,SF-36)评分高于术前,且术后观察组各项SF-36量表评分均高于对照组(P<0.05)。结论 对LDRG患者术后采用非离断Rouxen-Y吻合术可降低患者排气时间,降低RSS的发生率,同时不会增加其他并发症发生,并改善患者生活质量。
