Breakthrough in furniture coating with UV LED curing
Monday 27. May 2019 - First intelligent UV-LED based high-speed furniture coating line going into service utilizing inline UV monitoring and control
SC Freda, Lithuania’s oldest furniture company founded in 1880, has started production on their new high-speed furniture coating line. SC Freda specializes in manufacturing flat pack furniture from chipboard, MDF and cellular lightweight construction panels. The surfaces range from decorated paper surfaces with clear UV varnish, to highly pigmented UV coating systems.
SC Freda is a major supplier for IKEA manufacturing multiple product series.
As a measure to increase their manufacturing capacity, SC Freda expanded with a new production facility, featuring a high-speed production line with UV-curing. This new line must comply with the high IKEA quality and process control standards, to supply superior products. In addition, sustainability and energy efficiency are important topics that are taken into consideration to ensure a strategic, long-term investment, and to stay in forefront of sustainable manufacturing.
EFSEN UV & EB TECHNOLOGY, founded in 1986, are experts in radiation curing technology, with extensive experience in measuring and integrating UV-curing equipment for a wide range of applications and industries. Due to the strong heritage of furniture production in Denmark and its neighbouring countries, it has been natural for EFSEN to develop a unique understanding for optimizing curing solutions for the wood and furniture industry. With an innovative and dynamic team, EFSEN always thinks a step further in order to design solutions that are not only user friendly and safe but that also provides an energy efficient, long lasting, stable process to consistently deliver high performance products.
EFSEN and Freda has been working on optimizing UV for many years, and the discussions about the super-efficient and intelligent UV line started between Freda and EFSEN in 2017. There have been many things for Freda to consider, with cost efficiency, superior product quality and maximized production capacity being some of them. Their intention to implement modern, effective and environmentally friendly production process was key directives from the start of the project.
At EFSEN, this challenging request was highly appreciated. It was clear that the only reasonable way to supply a highly efficient and future-proof production line would be with UV-LED curing. While UV-LED curing in the wood industry is nothing unique anymore, the current UV-LED curing production lines are only using a fraction of the capability the UV-LED technology can offer. EFSEN wanted to go one step further, not limiting the use of UV-LEDs to gelling positions, which is how UV-LEDs are used in most lines. The intention was to change the whole process to UV-LED curing on all positions except the final top coat cure. The price / performance of conventional Mercury lamps can’t be matched yet for the final layer, due to the challenges of formulating price competitive UV-LED curing top coatings that meets the high resistance and colour accuracy requirements of a top coat.
Curing the sanding sealer with LED only is an industry first, and such a challenging task goes beyond what an equipment supplier can accomplish alone. With the high-power output of LEDs today, the primary limiting factor of the technology, and also the main cost driver, is the coating itself. Therefore, it was a benefit that Akzo Nobel was the designated coating supplier for this project. Akzo Nobel, a leading manufacturer of wood coatings, is known as an innovative company with extensive R&D capabilities. Already from the first discussions Akzo Nobel agreed into a cooperation to develop a UV-LED curable process which with as much UV-LED as possible, without a negative impact in coating price or properties. EFSEN has been working closely with Akzo Nobel, sharing not only the technical expertise, but also utilizing the chemical expertise of David Ivarsson, the EFSEN chemist, highly specialized in UV-LED formulations. In direct contact with Akzo Nobel, it was possible to develop a new curing process, replacing all conventional UV systems with the exception of Mercury lamps at the end of the production line. A key decision to make this a reality, was the choice of 365 nm LED for the sanding position.
Going through the normal coatings process, starting with sealing of the surface with two clear coats, following up with sanding the surface, and then proceeding to build the colour with multiple layers of base coats, to finally finish it off with a top coat, the challenge has been to find a process solution with only one LED unit in each position, replacing multiple conventional UV lamps on each station.
The conventional line setup which was the starting point at SC Freda is as follows, with 50 m/min as the target speed: