From their website:
Door Components began in a rented space in a warehouse in Pico Rivera, Calif., manufacturing hinge reinforcements, stick sections, and channels. The industry began to take notice, and our customers started asking for additional supplies and custom hollow metal doors and frames. In 1986 we responded by moving into our own 11,000 square-foot facility in Irwindale, Calif., allowing us to expand our manufacturing capabilities. With the addition of some new equipment, Door Components upgraded from making sticks to making jambs prepped with hardware, welding the jambs, and making complete door frames.
Over the next 10 years we built a reputation as the service company that manufactures hollow metal doors and frames, and business was booming. In 1997 we moved again into a 45,000-square-foot facility in Rancho Cucamonga, Calif., and in 2000 we opened another 45,000-square-foot facility to accommodate the increased need for manufactured doors.