There is a limit block under the hook on the packing tensioner fixed mode, which is bonded to the back of the hook; the screw on the second moving mode as described by the tensioner manufacturer is connected to the screw, which is connected to the fixed mold by rotating the other end of the screw, and there is a manual wheel connected to the driving end of the screw. Fast tensioner beneficial effect: molten metal liquid enters the cavity through the hole on the fixing, the molten metal liquid is cured by pressure, after forming the workpiece, the worm drives the screw to rotate, the screw is fixed axially, the second motion die causes the screw to move axially, pushing the second motion mode to move, and the hook is under the restrictor block of the fast tensioner, and the hook of the hook and the shoulder of the table on the second motion mode are closely adhered together.