5600b
hy-5600b印刷体耐磨擦试验机操作规范(编辑修改稿)
、 400水砂纸、 铅笔硬度测试仪；Preparation: 2B Zhonghua brand drawing pencil, Great Wall brand drawing eraser, pencil sharpener, water abrasive paper and pencil hardness tester. b. 试用铅笔的备制，用削笔刀削去木杆部分，使笔芯呈圆柱状露出约