麻花钻外圆转点倒角对切削性能的影响

为了提高麻花钻的寿命,减小外圆转点处崩刃,采用六支外圆转点处不同倒角宽度的麻花钻对45#钢进行钻孔试验。通过分析钻削加工中的轴向力、扭矩和刀具表面质量,研究了麻花钻外圆转点处倒角对钻削加工的影响,试验结果表明倒角宽度为0.5~0.7mm时,切削性能最佳。

扩孔用硬质合金立铣刀的试验研究

整体硬质合金立铣刀也用于扩孔加工,其周齿设计与普通铣刀、钻头不同。在使用过程中存在的主要问题有切削噪音大、外转点处容易崩刃。分析实际加工条件的特征后,修改原设计的周齿和刃口形式。经过试验,解决了加工中的噪音和外转点的崩刃延长刀具寿命近两倍,提高加工效率。

Predictive factors of lymph node metastasis in intramucosal poorly differentiated early gastric cancer and their impact on the laparoscopic surgery

Objective The aim of this study was to identify clinicopathological factors predictive of lymph node metastasis (LNM) in intramucosal poorly differentiated early gastric cancer (EGC), and further to expand the possibility of using laparoscopic surgery for the treatment of intramucosal poorly differentiated EGC.