Air groove structure of lower pressing head of grinding sub four-cavity hot pressing die

The utility model discloses an air groove structure of a lower pressing head of a four-cavity hot pressing die of a grinding head, which comprises a blocky lower pressing head, an air escape part is arranged on the outer surface of the lower pressing head, and the outer surface of the lower pressing head is provided with an upper end face, a lower end face and a side peripheral face located between the upper end face and the lower end face. And the air escape part extends from one end surface to the other end surface and can discharge air out of the mold. According to the utility model, the air escape part is arranged, and the size of the air escape part is limited, so that the vacuum air of the mold in the pressing process can be completely exhausted in the range of less material escape of product powder materials, and the problem of air hole cracking of the product caused by incomplete vacuum exhaust in the pressing process is effectively solved; meanwhile, the exhaust frequency and time are reduced for man