Door and window corner combining production line and working method

The invention relates to a door and window corner combining production line and a working method, and the door and window corner combining production line comprises a feeding unit which comprises a material conveying mechanism and a panel with a positioning roller and is used for receiving a pre-assembled door and window and driving the pre-assembled door and window to move towards a fastening unit through the material conveying mechanism; the fastening unit receives the pre-assembled door and window or the door and window from the overturning unit, fastens the four corners of the door and window from the upper surface and conveys the door and window to the overturning unit; the overturning unit comprises a clamping support, a fixed conveying frame and a movable conveying frame which are arranged in parallel are arranged on the clamping support, the fixed conveying frame and the movable conveying frame get close to each other to clamp doors and windows, the driving assembly drives the clamping support to rota