(1) High machining accuracy is required（Li-battery pump). A pair of molds is generally composed of concave die, punch and mold base, and some may also be multi piece modules. Therefore, the combination of upper and lower dies, the combination of insert and cavity and the combination between modules all require high machining accuracy. The dimensional accuracy of precision molds often reaches μ Class M.

(2) The shape and surface are complex(Li-battery pump). The surface of some products, such as automobile panels, aircraft parts, toys and household appliances, is composed of a variety of curved surfaces. Therefore, the mold cavity surface is very complex. Some surfaces must be treated mathematically.

(3) (Li-battery pump)The production of small batch molds is not mass production. In many cases, only one pair is produced.

(4) There are many processes, such as milling, boring, drilling, reaming, tapping and so on.