Laminate route to flexible circuit boards
Walki-4E technology is a new way of producing flexible circuit boards using a dry process and paper as the substrate
A new patented approach from a Finnish company is challenging the use of etching to produce flexible circuits for RFID antennae.
Developed by Walki, the Walki-4e method produces flexible circuit boards efficiently and sustainably using a dry production process. It involves no liquid chemicals and uses paper as the substrate. It also allows for computer to antenna production and extremely accurate laser cutting of the circuit board patterns.
The traditional way of producing RFID antennas by etching has for a long period undergone only modest development. Walki, a leading producer of technical laminates, looked for ways to simplify the manufacturing process, while making use of its knowledge in lamination.
“We think that Walki-4E technology is the first feasible alternative to etching and that it will bring new dimensions of cost efficiency and sustainability to the industry,” says Sami Liponkoski, global product manager at Walki.
The process involves making a special laminate of aluminium and and a paper substrate. The aluminium foil is then cut in patterns using a laser.
The technology can be used for any flexible circuits boards, from RFID antennas to boards for radiators and flexible displays. The first product to be launched using Walki-4E technology is Walki-Pantenna, a UHF RFID antenna.
The four E’s of Walki-4E stand for efficient, exact, economical and ecological. Compared with etching, the technology eliminates a whole step from the tag production process or from the converter’s process, thus combining efficiency and economy.
“Since paper is used as a substrate, the RFID manufacturers can leave out the insertion of the PET inlay into paper, a necessary step when the antenna has been produced by etching. Moreover, the computer to antenna production method speeds up design and development, an advantage especially when it comes to producing short series, involving a fewer number of antennas,” Sami Liponkoski says.
Cost efficiency comes hand-in-hand with environmental benefits. The dry process does not involve any chemicals, thus resulting in process residue that is easily recyclable. The absence of liquid chemicals also leaves the RFID manufacturers with a product that is 100 % recyclable.
“Since the antenna is free from plastics, made of paper and aluminium only, it is easily recycled in a fibre recycling process, where metal detectors sort out the aluminium.” Sami Liponkoski says.
The precision of the laser cutting of the patterns allows for smaller chips, greater repeatability in the production process and higher accuracy of the antenna.
“This does not only overcome certain accuracy problems that etching brings, but also gives new possibilities for developing the antennas and the chips,” Sami Liponkoski says.
Digitalisation of the production process, i.e. computer to antenna production, brings efficiency and allows for an endless number of variations in the patterns.
“Our vision is that the antenna production eventually will be completely digital. Laser cutting can speed up the production process by ten times, and taking into account the development that laser technology undergoes every year, the possibilities of producing flexible circuit boards with lasers are almost limitless,” Sami Liponkoski says.
Walki’s first product, Walki-Pantenna, will be ready for mass production in 2012.
“We are now in the ramp-up phase for our new production line in Pietarsaari, Finland, and we are looking forward to introduction in the market. There is a lot of interest in our product and we strongly believe it has the capacity to change the industry,” Liponkoski says.
Caption: Walki-4E technology is a new way of producing flexible circuit boards using a dry process and paper as the substrate, the first real alternative to the wet, chemical based process of etching.
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