Certified structural steelwork, CNC machining, welded assemblies and electrical installation for plant and mechanical engineering.
Schweiß- und Metallbau-Centrum Steffen GmbH
Königsee OT Rottenbach · AmmelstädtNew on Amplifa
About SMC Steffen
SMC Steffen GmbH, based in Königsee OT Rottenbach (Thuringia), has been manufacturing customised solutions in steel and metal construction since 1989. The company produces steel assemblies made of carbon steel and stainless steel up to the assembly of complete systems, including certified load-bearing steel structures according to DIN EN 1090 (EXC2), steel structures for battery formation systems, louvre systems, damper systems and pressure relief flaps made of steel and aluminium. The service portfolio also includes CNC milling and CNC drilling of components up to 3000 x 1000 x 1100 mm, CNC turning, welding of assemblies on two welding robot systems as well as electrical installations up to small-scale switchgear construction. Production covers single parts as well as series. With around 2300 m² of production space at the main plant in Königsee and 800 m² at the Ammelstädt plant, which has been in operation since 2024, the company supplies industries such as plant engineering, mechanical engineering, steel construction and automotive engineering with 50 employees.
- Site
- Königsee OT Rottenbach
- Processes
- CNC machining milling, CNC machining drilling, CNC turning, Welded assembly manufacturing (welding robots, MAG, MIG/TIG, manual arc welding), Sawing/cutting (band saw, double mitre saw), Certified structural steelwork according to DIN EN 1090 (EXC2), Steel and light metal construction (louvre systems, damper systems, pressure relief flaps), Assembly of complete systems / large-scale systems
- Materials
- Carbon steel (load-bearing steel structures), Stainless steels (stainless steel), Aluminium, Carbon steel, Stainless steel
- Certificates
- DIN EN 1090-1 (CPR, EXC2), Welding certificate EN 1090-2, Sustainability agreement Thuringia, DIN EN 1090-1 (EXC2)
- Founded
- 1989
- Employees
- 50
- Industries
- Plant engineering, Mechanical engineering, Steel construction, Automotive engineering, Industrial sector, Battery formation systems
- 01
Cutting (band saw, double mitre saw)
- 02
CNC milling and CNC drilling
- 03
CNC turning
- 04
Welded assembly manufacturing (welding robots, MAG, MIG/TIG)
- 05
Certified structural steelwork according to DIN EN 1090
- 06
Assembly of complete systems
- 07
Electrical installation and switchgear construction
Materials and Processes
Carbon steel
Load-bearing steel structures and welded assemblies for steel construction, plant and mechanical engineering according to material group 1.1/1.2 per CEN ISO/TR 15608.
Stainless steel
Stainless steels for corrosion-resistant steel assemblies and welded constructions.
Aluminium
Light metal for constructions such as louvre systems and damper systems in industrial applications.
Locations
Königsee OT Rottenbach
DEMain plant: production, CNC machining, welding, warehouse
- Part weight / size
- Components up to 3000 x 1000 x 1100 mm (CNC)
- Lot size
- Single parts up to series production
- Materials
- Carbon steel, stainless steel, aluminium
- 2 welding robot systems
- 3-axis CNC machining centre 2350 x 1000 mm, Z=1000 mm, with swivel axis
- 4-axis machining centre 3000 x 1050 mm, Z=1300 mm, with swivel axis
- 4-axis machining centre 3000 x 1000 mm, Z=1100 mm, with swivel axis and rotary table Ø1000 mm
- Travelling column milling machine Ibarmia (2023, components up to 3000 mm length)
- CNC lathe with sub-spindle and driven tools (up to 560 mm turning length, from December 2025)
- CNC drilling-milling machine for steel beams
- Fully automatic drilling machine (2020)
- Double mitre saw technology (2020)
- 2 CNC-controlled band saw systems
- Tacking and welding workstations with positioning technology and welding/clamping tables
- Industrial robot system (2025)
Ammelstädt
DEPlant 2: certified structural steelwork, assembly of large-scale systems (since October 2024)
- Part weight / size
- Large assemblies (5 t crane load capacity)
- Lot size
- Large-scale systems and assemblies
- Materials
- Steel, stainless steel
- Hall crane 5 t load capacity
- 3 gates accessible to trucks
- 800 m² hall for welding projects and assembly
Components and Services
Inside the production
Industries
Processes & technical limits
| Processes | Tolerance | Max. part | Weight | Lot size | Materials |
|---|---|---|---|---|---|
| CNC machining millingMachining | – | 3000 mm × 1050 mm × 1300 mm | – | Single parts – Series production | Steel, Stainless steel, Light metal |
| CNC machining drillingMachining | – | 3000 mm × 1000 mm × 1100 mm | – | – | Steel, Stainless steel, Light metal |
| CNC turningMachining | – | 560 mm | – | – | – |
| Welded assembly manufacturing (welding robots, MAG, MIG/TIG, manual arc welding)Joining | – | – | – | – | Steel, Stainless steel |
| Sawing/cutting (band saw, double mitre saw)Machining | – | – | – | – | Steel |
| Certified structural steelwork according to DIN EN 1090 (EXC2)Assembly | – | – | – | – | Steel, Stainless steel |
| Steel and light metal construction (louvre systems, damper systems, pressure relief flaps)Joining | – | – | – | – | Steel, Aluminium, Stainless steel |
| Assembly of complete systems / large-scale systemsAssembly | – | – | – | – | Steel |
| Electrical installation up to small-scale switchgear constructionAssembly | – | – | – | – | – |
13 Anlagen & Maschinen
| Machine | Manufacturer / model | Quantity | Working area | Year built | Site |
|---|---|---|---|---|---|
| Welding robot system | – | 2 | – | – | Königsee plant |
| 3-axis CNC machining centre with swivel axis | – | 1 | 2350x1000 mm, Z=1000 mm | – | Königsee plant |
| 4-axis machining centre with swivel axis | – | 1 | 3000x1050 mm, Z=1300 mm | – | Königsee plant |
| 4-axis machining centre with swivel axis and rotary table Ø1000 mm | – | 1 | 3000x1000 mm, Z=1100 mm | – | Königsee plant |
| CNC lathe with sub-spindle and driven tools | – | 1 | up to 560 mm turning length | 2025 | Königsee plant |
| CNC-controlled band saw system | – | 2 | – | – | Königsee plant |
| CNC drilling-milling machine for steel beams | – | 1 | – | – | Königsee plant |
| Travelling column milling machine | Ibarmia | 1 | Components up to 3000 mm length | 2023 | Königsee plant |
| Fully automatic drilling machine | – | 1 | – | 2020 | Königsee plant |
| Double mitre saw technology | – | 1 | – | 2020 | Königsee plant |
| Tacking and welding workstations with positioning technology and welding/clamping tables | – | – | – | – | Königsee plant |
| Hall crane | – | 1 | 5 t load capacity | – | Ammelstädt plant |
| Industrial robot system | – | 1 | – | 2025 | – |
Additional services
Quality and Certification
The company is certified according to DIN EN 1090-1 for load-bearing steel structures up to EXC2 (DVS ZERT GmbH) and holds a welding certificate according to EN 1090-2 for manual arc welding, MAG and TIG welding on carbon and stainless steel. The welding production is under responsible welding coordination (IWS); the in-house production control is monitored by the notified body.
| Evidence | Königsee OT Rottenbach | Ammelstädt |
|---|---|---|
| DIN EN 1090-1 (EXC2) | ||
| Welding certificate EN 1090-2 |
Company History
- 1989
Founding of the forge and metalworking shop of Uwe Steffen from a part-time trade into self-employment
- 1990
Completion of the master craftsman studies "Master Metalworker" by Uwe Steffen
- 1993
Expansion of the service portfolio with the qualification of a master electrician
- 1994
Expansion of the electrical installation segment up to small-scale switchgear construction
- 1999
Company foundation "Schweiß- und Metallbau-Centrum Steffen GmbH" with the construction of a new production hall as well as a warehouse/cutting hall; entry into the industrial sector
- 2005
Expansion of the company premises in Rottenbach to 3.500 m² of property size
- 2009
Company anniversaries "20 years forge and metalworking shop" and "10 years SMC Steffen GmbH"
- 2013
Merger of Schweiß- und Metallbau-Centrum Steffen GmbH and Metall- und Elektrobau Steffen
- 2014
New acquisition of a CNC machining centre for large-part milling; first issuance of the EN-1090 certificate
- 2016
Reconstruction of the production hall in industrial and commercial area 16
- 2018
New acquisition of another CNC machining centre for large-part milling
- 2020
New acquisition of a fully automatic drilling machine and double mitre saw technology; construction of a cutting/warehouse hall with 450 m²
- 2023
New acquisition of an Ibarmia travelling column milling machine for components up to 3000 mm length
- 2024
Expansion of production capacity by 800 m² at the new Ammelstädt plant (in operation since October 2024)
- 2025
Acquisition of a modern industrial robot system; planned addition of a CNC lathe with sub-spindle from December 2025