Headbox is known as the "heart" of paper machine. It is the key component of paper machine, the hub connecting "flow" and "forming". It is also one of the fastest developing components of paper machine. In papermaking, the function of the headbox is to send the required pulp to the forming net according to the requirements of the forming part of the paper machine, so as to provide a necessary premise for the good forming of the paper web.

　　As the combination of "flow" and "forming" of the paper machine, the basic task of the headbox is to provide good preconditions for paper sheet forming, that is, evenly distribute the paper material along the width direction of the paper machine to ensure the uniform distribution of pressure, speed, flow, concentration and fiber orientation controllability and uniformity; Effectively disperse pulp fibers, prevent fiber flocculation, and provide and maintain stable sizing head and pulp net speed ratio according to process requirements.

　　In the long-term development of pulp and paper technology, although there are many structural forms of headbox, its main functions remain basically the same, namely pulp distribution, homogenization and spraying.