How many spare cylinders are available?

Generally speaking, according to the wearing parts, more wearing parts should be prepared, and at least two sets of non-wearing parts should be prepared if the procurement cycle is long. Spare parts refer to unfinished processed products, such as metal parts to be finely ground and balls to be dipped in fire. Spare parts refer to the processed parts prepared for the processed products and the main engine, such as outsourced standard parts and various cutterheads for the main engine.