Trehøje døre

Retrofit of actuators for polishing machine

Trehøje Døre A/S is a modern, consolidated Danish wood industry company which manufactures a wide portfolio of internal doors.


Trehøje Døre has an old machine for polishing of door frame seals where 5 polishing brushes automatically adapts to the seal height and width. Previously, they were controlled by 5 pneumatic cylinders with oil brakes, which – contrary to traditional pneumatic cylinders – are able to stop in a given position. As the cylinders were worn down and discontinued, a new system was needed for the brush movements.

The solution

The existing defective cylinders were replaced with electric actuators of the same length of stroke. As the existing control was unchangeable, a new electrical panel with a new PLC was designed to control the electric actuators. For each actuator, the signals for the existing valves are led into the new PLC control which controls when the actuators are activated. The new control is controlled by the main machine and is also turned off at the same time. The operating signal is transferred to ensure that the new actuators are controlled automatically. Moreover, signals from emergency stops and door contactors are transferred too so that the new actuators are implemented directly in the existing safety circuit.

The benefits

With the fitting of the modern electric actuators, the speed, acceleration and deceleration can be adjusted and thus ensure a more optimal movement of the polishing brushes. The electric actuators provide a more energy efficient and sustainable solution compared to the pneumatic solution which was used before the retrofit.

The opportunities

With Tech Invent as a business partner, we can offer Trehøje Døre continuous assistance to optimize its production – partly with updates of existing equipment, partly in the development of new machines or production equipment where a standard solution is not already available for the project. When Tech Invent is developing new equipment, standard components are selected to a great extent so that the equipment will be as simple and affordable as possible in purchase and servicing.

The outcome of the cooperation

Instead of purchasing a new machine, the task was completed by retrofitting electric actuators and associated control which – in terms of safety and quality – ensures that the machine can remain in operation many years ahead. Thanks to this update, the energy consumption of the machine is reduced, which thus leads to operational savings in the production.
“We had a machine that did not work, and therefore we contacted Tech Invent which quickly understood this special project and intended to find the right solution. Our communication about the project was excellent, the process was every efficient, and today we have a well-functioning machine which is now updated with a minimal interruption of our operations.”

Flemming Larsen – Production Manager at Trehøje Døre A/S