If the grinding wheel is dull, it means that the quality of the grinding wheel is not good and the internal fraud of the grinding wheel is too serious. If the sand is dull, it means that you have used up all its edges and corners. The sand is round, so it is dull, which leads to the decrease of polishing efficiency and poor effect.
The grinding wheel can only be restored to a good working condition after dressing, which can be divided into shaping and sharpening.
Plum trees are easily infected with diseases and insect pests under poor management conditions, which affects the developmen