Casting sand box for 3D printer

The utility model discloses a casting sand box for a 3D printer. The casting sand box comprises a box body, a convex plate and a residual sand recycling box, the upper portion and the lower portion of the box body are both of an opening structure, the protruding plate is arranged on the upper portion of the box body and forms a step structure on the upper portion of the box body, and the protruding plate is provided with an opening with the same caliber as the opening structure of the upper portion of the box body. The residual sand recycling box is arranged on the periphery of the box body and located on the same horizontal plane with the protruding plate on the box body. The residual sand recycling box is designed on the periphery of the box body, the scraper below the printer nozzle can scrape the surface of sand to be flat, redundant sand falls into the residual sand recycling box, the redundant sand is prevented from being scraped to other positions of the printer, meanwhile, the redundant sand is effect