Moving column type gantry milling machine driven by single lead screw and assembling technique thereof

The invention discloses a moving column type gantry milling machine driven by a single lead screw and an assembling technique of the moving column type gantry milling machine. The moving column type gantry milling machine driven by the single lead screw comprises a bed body, a workbench, a first slide table, a portal frame, a second slide table, a main shaft component and a lead screw, wherein a rectangular gap is arranged between the workbench and the bed body, the first side table passes through the rectangular gap, and the first slide table is glided along lead rails at both sides of the bed body; the portal frame is rigidly connected with the first slide table to form a hollow square shaped structure; a second slide table is arranged between the main shaft component and the portal frame, and the second slide table is crossly glided along a cross arm of the portal frame; the main shaft component is glided in longitudinal direction along the slide rail of the second slide table, and middle part of the bed body is provided with a sole lead screw; the middle position of a bottom part of the slide table is fixed with a lead screw nut. The structure has very good rigidity of the mobile portal frame at the greatest extent, and largely improves the stress deformation of the device at work, promotes equipment precision, simplifies assembling technique; moreover, requirement on the control stem is low, and cost is saved.