ONEJOON GmbH is a German based thermal processing equipment manufacturer with locations in Bovenden and Böblingen Germany. ONEJOON recently acquired Eisenmann Thermal Solutions and the new company has a combined 100 years of experience with high temperature equipment used in the Thermal Processing industry. ONEJOON GmbH has 195 employees at its locations in Germany, 108 of them in Bovenden and 87 in Böblingen.

ONEJOON is the technology and market leader for oxidation ovens and carbonization furnaces used in the production of carbon fiber. ONEJOON also has a very strong position in the markets for cathode and anode material production for lithium-ion batteries. Other key target markets include the following:

  • Hardening of blades and saw bands
  • Sintering of metals and ceramics
  • Heat treatment of aluminium wheels and structural parts
  • Powder chemistry and advanced materials

ONEJOON supplies not only customized furnace technology but can also provide all supporting equipment and services as well. This includes the application of automation equipment, material flow expertise, process integration and system optimization.

Since the acquisition of Eisenmann Thermal Solutions in January 2020, all operations in Germany, USA and China are now subsidiaries of ONEJOON Group.

The parent company ONEJOON Co., Ltd. is a mechanical engineering company based in Suwon, South Korea, whose primary market is the production of high temperature furnace systems including the required material handling and process technology for the treatment of cathode and anode material in lithium-ion batteries.

Head Office in Bovenden

Company History

ONEJOON Germany looks back on a long company history. In 1888, the two brothers Adolf and Ernst Ruhstrat founded an electrical shop, which soon developed into a medium-sized family business. 

In 1894, Ruhstrat, in cooperation with the Nobel Prize winner Prof. Walter Nernst, University of Göttingen, created the basis for setting or changing resistances as well as current and voltage with the adjustable sliding resistor. Further development led to the construction of the first resistance-heated high-temperature furnace in 1896 and, from 1898, to the transfer of the construction of high-temperature furnaces for industrial purposes to the "Elektromechanische Werkstätten Gebr. Ruhstrat". Since this time Ruhstrat has manufactured high-tech industrial furnace systems up to 3000 °C for a wide variety of heat treatments.

In 2011 Ruhstrat was taken over by EISENMANN AG and incorporated into Eisenmann Thermal Solutions GmbH & Co. KG. By bundling the core competences for carbon fibre production under one roof, far-reaching synergy effects were opened up both in product development and in sales and project management.

The cooperation between ONEJOON Korea and Eisenmann Thermal Solutions (Germany) started in 2016 on the basis of a cooperation agreement.

This was followed in 2018 by a joint order for a major battery material project in Asia (battery furnaces and process equipment). 

2019 saw the establishment of the joint venture "Eisenmann Thermal Solutions (Zhejiang) Co. Ltd." in China between ONEJOON Korea and Eisenmann Thermal Solutions GmbH & Co. KG.

After the Eisenmann Group's economic difficulties in the same year, ONEJOON Co., Ltd. Korea acquired Eisenmann Thermal Solutions GmbH & Co. KG in January 2020 and founded ONEJOON GmbH with headquarters in Germany.


Zeitstrahl 2020 GB


Bovenden and Böblingen


Head Office:
Auf der Mauer 1, 37120 Bovenden, Germany

Office South Germany:
Tübinger Str. 81, 71032 Böblingen, Germany

Size of the administrative and production areas

Head Office & Factory (Bovenden)

  • Land area: 50.000 m2
  • Production area: 7.500 m2, thereof 500 m2 Test Center
  • Administration area: 2.000 m2

Office South Germany (Böblingen)

  • Administration area: 1.650 m2

Management Board in Germany

André Goernhardt Managing Director/CEO +49 551 820 830 - 0
Wilkens Detlef
Detlef Wilkens Managing Director/COO +49 551 820 830 - 0
Company Profile
ONEJOON Korea read more
Company Profile
ONEJOON China read more
Company Profile
ONEJOON USA read more
Heat treatment plants More than 120 years experience in industrial furnace construction
ONEJOON GmbH Bovenden, Germany +49 551 820 830 - 0