Advances in technology has magnified the potential in furniture design infinitely with new machinery and processing techniques enabling the manufacture of work pieces featuring complex and imaginative contours and shapes. The design sandbox has been extended from orthodox box-shaped templates to free forms in any direction.
Naturally, coating and surface technologies have also evolved accordingly to provide protection and decoration for sophisticated designs that are becoming more and more common in the market and to consumers. In recent years, development of surface finish has been geared towards the concept of seamlessness by reducing the thickness of the adhesive layer or eliminating edge joints altogether.
In this regard, 3D thermoforming can provide many advantages. Initially introduced as a cheap alternative to surface treatment for door applications, the technology has been improved over the years and embraced by the furniture manufacturers.
“Decorative thermoplastic films for 3D thermoforming application are widely established in the furniture industry,” Florian Hauswirth, sales manager of Klöckner Pentaplast, said. “In particular, furniture fronts and cabinet doors are laminated with such decorative films. The range of use covers furniture for living rooms, kitchens and bathrooms, as well as for shop fitting, hospitality and the office area.”
The main draw of 3D thermoforming lies in its ability to conform and wrap around the contours of the substrate to create curved profiles and seamless components. As a result, there is no need for edgebanding or T-moulding.
During application, thermoplastic films are applied and glued onto medium density fibreboards (MDFs) or other types of panels. Normally, boards with melamine paper layer on the back side are used. Prior to pressing, the MDFs are formatted, sized and profiled to their final shape.
Thermoforming is done through a ‘vacuum press’ process. Unlike normal presses, these vacuum presses do not apply pressure from the top using a press plate. Instead, they develop an under pressure from underneath the workpiece in a way such that the thermoplastic film is ‘sucked’ onto the surface of the MDF.
Bonding between the film and the board is secured with PUR glue. Glue application can be done with manual spraying equipment or, alternatively, by spray robots. The gluing process is activated by heat during the vacuum pressing cycle. It is recommended to use decorative films with a primer layer on the back.
High performance presses are equipped with an additional rubber membrane which is positioned on top of the workpieces. Through the vacuum created from underneath, the membrane adheres tightly to the shape of the workpiece. This equipment type, also known as the ‘membrane press’, can improve the vacuum effect considerably and improves the efficiency of the process.
“The 3D thermoforming technology offers a small, yet decisive side effect—simultaneously with the surface lamination, the decorative film encapsulates all edges,” he added. “All contours, profiles and even the angles and corners of the workpiece are neatly and tightly wrapped by the film.”
As a result, the edges are sealed and protected in one single manufacturing process and using one single surface material. No additional edgebanding process is required.
“Colour matching of surface and edge materials is not an issue any more.
Moreover, there is no glue joint between the flat surface and the edge which is considered a visual quality advantage.”
According to Mr Hauswirth, 3D films are typically made of polyvinyl chloride (PVC), but also other polymers found in the market, such as polyethylene terephthalate (PET) and polypropylene (PP).
“PVC offers excellent physical properties that make downstream processing particularly convenient,” he said. “The broad operable temperature range of PVC provides for a high processing safety.”
High-end 3D films are usually made from plasticiser-free PVC to ensure no harmful substance can vaporise from the furniture into the living environment. Plasticiser-free PVC films are also suitable for children rooms.
Another crucial feature of high-quality films is the surface finish: it is important that the film surface is lacquered with a resistant varnish system. In this way, products will be resistant to cleaning and the decorative layer will be protected from scratching and from other mechanical and chemical influences.
In the past, the decorative layer typically features a solid colour with no pattern or design. These days, there is a magnitude of different colour combination and textural pattern options to choose from with the mimic of other construction materials, such as wood, metal and even fur, becoming more popular. The rich details and realism offered by the decorative layer makes it a particularly intriguing component in design, allowing designers to flex their brain muscles to achieve the desired interior effects.
“A wide range of unicolours and of printed wood grain designs is available in the market,” he said. “Gloss grades can be super matt, silk matt, normal matt and even extremely brilliant. Brilliance can go up to 85 gloss and higher which is another benefit compared with other surface materials.”