Preparation method of one-step molded sintered neodymium-iron-boron magnet

The invention discloses a preparation method of a one-step molded sintered neodymium-iron-boron magnet. The preparation method comprises the following steps: a, smelting to obtain an alloy sheet; b, hydrogen decrepitation and powder preparation: preparing the obtained alloy sheet into coarse powder by adopting a hydrogen decrepitation process, preparing the coarse powder into fine powder by virtue of airflow grinding, pouring the fine powder into an active stirring device for stirring, adding an agent by virtue of an agent adding device in the stirring process, and sub-packaging the powder into a powder barrel after the stirring is completed; c, pressing: enabling the powder in the powder barrel to fall into a feeding device, homogenizing the apparent density of the powder in the feeding device by adopting a homogenizing device, progressively adding the powder in the feeding device into a die cavity by controlling the floating speed of a female die of a pressing machine, and pressing the powder into a one-ste