Hollow Metal Door Manufacturing Process

The process begins with blanking of cold-rolled carbon steel or galvannealed sheet — in gages from 18 ga through 14 ga for frames, and from 20 ga through 16 ga for doors.

Each blank is then formed on press brakes to tolerances that do not accept dimensional variation greater than 0.030 in. (30 thousandths of an inch). Once the part is formed, all internal hardware reinforcements are spot-welded in place.

Door leaves are transferred to the assembly tables, where the fire-retardant core is installed and the top and bottom channels are spot-welded closed. The finished doors are then painted using an automated electrostatic paint system.

Frames are washed, phosphate-treated, and painted through a spray-booth tunnel. They are then oven-cured to set the finish.