The Hilchenbach site is where SMS group has its roots. Today, on the same spot where offices and workshops cover an area of 145,000 square meters, the Klein brothers built an iron foundry in 1834. The factory halls initially faced an east-west direction along the Wittgensteiner Strasse. The first halls facing north-south were built at the beginning of the 20th century. The site was given a new administration building in 1923, currently known as building A. In 1927, Siegener Maschinenbau AG (Siemag) took over the company from the Klein brothers and moved its headquarters from Siegen to Dahlbruch.

The growth of the company and the expansion of its production portfolio meant the site had to be steadily expanded from 1960 onwards. The large assembly shop, also known as the 'high bay', was built first. It still shapes the landscape of the location today. In the decades that followed, SMS group continued to expand its site to accommodate more offices, workshop space, and new IT headquarters.