HelioChrome NEO – or: Changeover from chromium VI to chromium III now getting serious
von Ansgar Wessendorf,
To increase the sustainability of the gravure printing process in general and the cylinder preparation in special, the industry is developing promising alternatives to the traditional chromium (VI) trioxide coating, such as chromium (III) chloride or polymer and elastomer coatings. After more than 10 years of development by German company K Walter and co-partner Huhtamaki Ronsberg, the HelioChrome NEO electroplating technology is a Chromium(III) based alternative to the Chromium(VI) process. It reached industrial maturity in 2021 and is already in successful use by some companies.
Growing interest in the new technology
In July, representatives of 4 Packaging, a leading German company in the field of the production of gravure cylinders and embossing dies as well as digital reproduction, visited Kaspar Walter to talk about the new sustainable future of chrome plating with HelioChrome NEO. Prior to this, Kaspar Walter had a lot of visitors already explored this new technology, with the 2nd machine now ready to go.
In addition, representatives of Daetwyler UK and Riverside Gravure Ltd., a Great Britain based specialist gravure cylinder manufacturer visited Huhtamaki Ronsberg to see the technology in person. As a co-development partner, the company already runs a HelioChrome NEO device. According to Huhtamaki, they were very impressed by this new technology.
The HelioChrome NEO electroplating technology
In 2015, the proven and trusted partnership with Kaspar Walter saw the installation of a newly developed system for the chrome plating of gravure cylinders at Huhtamaki Flexible Packaging Germany in Ronsberg.
The objective of this development was to achieve environmentally friendly plating by using chrome (III) technology that matched the mechanical properties and quality standards offered by chrome (VI) plating. Various electrolyte formulations and system modifications were tested and refined, and Kaspar Walter has subsequently awarded several patents for this new chrome plating process. Known as HelioChrome NEO, this new plating technology is now commercially available.
With a Vickers hardness of around 1200 HV, it is possible to achieve cylinder surfaces with HelioChrome NEO that match classic chrome plating using chrome (VI). What’s more, there are no fundamental changes in the workflow for the user, although it is not possible to use current chrome (VI) plating systems for the HelioChrome NEO process. However, the same grinding and polishing systems can be used which means that the surface of the new chrome layer does need to be worked in a different way as chrome (VI).
A step forward in sustainability
At around 20 A/dm² at 40°C, the energy demand of HelioChrome NEO is relatively low and the bath temperature is 20 degrees lower than for classic chrome plating. As a result, the environment benefits from lower emissions and energy costs are also lower. Currently, it is possible to deposit chrome (III) layers up to 25 µm thick and it takes around 20 minutes, or roughly the same time as with chrome (VI) plating, to lay down the 6 to 8 µm thick layers that are usual in gravure printing. Chrome (III) salts have also proved to be less harmful to the environment and health than chrome (VI) salts. Their toxicity is less than that of the copper bath, so no REACH authorization should be required.