PSO pioneers in sheet metal printing

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Hoffmann Neopac, using Zeller+Gmelin’s Uvalux U3 UV ink series, has become the first printing plant to gain PSO-certification for sheet metal printing with UV inks. In conventional printing the Process Standard Offset printing (PSO) criterion which is covered by the international standard ISO 12647-2, has been established for a number of years. For Hoffmann Neopac AG, however, the certification was a special challenge as the company specialises in UV-offset printing of metal sheet. The core business at the location Thun in Switzerland is the production of high-quality printed pocket packs, metal tins and metal/plastic dispensers for the confectionery, tobacco and food industry. For this market segment the printer was therefore unable to refer to any previous history of sheet metal printing with UV-inks according to the PSO standard.

Originally, Process Standard Offset printing was developed by the unions of the printing and media industry together with the research institutes Fogra and Ugra and was only for printing on paper. There were therefore no existing standards for the printing of tin plate sheets. Moreover, Hoffmann Neopac focused on the use of UV-curing printing inks, leading to even greater difficulties in achieving this accreditation.

The company firstly acquired the PSO-certificate for the pre-press department and then worked towards adding the verification for print at a later stage. This was successfully achieved in August 2009.

The company Hoffmann Neopac therefore became the first printing plant world wide in the field of metal printing to possess Process Standard Offset certification for printing sheet metal using UV inks. As a result Hoffmann Neopac now leads the way in quality management for this segment of tin plate sheet printing.

The Hoffmann-Neopac-group which includes Neopac in Oberdiessbach/Switzerland and Tu-Plast in Debrecen/Hungary, both producing tubes, employs more than 600 staff in total. Around 85% of their production is exported, mainly to European countries, but also to the USA, Japan and China. In the USA and in South Korea the company works with partners who have obtained a production licence from Hoffman-Neopac-group.

Thanks to the PSO-certification, the company feels able to guarantee a consistant quality from pre-press to offset printing. “This is achieved because we have made the entire process chain measurable and checkable“, says Guntmar Ludin, Manager of the printing plant at Hoffmann Neopac. Due to the absence of standards for the printing of coated tin plate sheets the values related to paper classes 1 and 2 were used for the certification.

With their successful certification Hoffmann Neopac has shown that in the field of metal printing it is also possible to produce orders from receipt of data to the finished print product within the narrow tolerances of standard ISO 12647. At the same time it also demonstrates that for repeat orders accurate reproducibility can be guaranteed.

Guntmar Ludin confirmed that the printing inks that had been used contributed considerably to their success as they complied in all respects with the unique requirements of printing on metal. The inks supplied by Zeller+Gmelin GmbH & Co KG were their Uvalux® U3 series which having S4100 to S4400 specifications were tailor-made for the process of the PSO-certified metal sheet printing. In additon, the ink specialists from Eislingen contributed their wide experience and expertise in UV-offset printing as support for the certification process.

As well as process inks and Pantone basic inks the Uvalux® U3 series includes a mono-pigmented basic ink mixing system and an opaque white with good formability and high opacity. These radiation curing printing inks have been especially developed for the field of metal printing and decoration. They offer high flexibility and very good adhesion on lacquered metals. As Michael Rakoci the application engineer for Zeller+Gmelin‘s metal decoration product range explained that this is the basic requirement for trouble-free processing in the forming and deep-drawing process. Moreover Michael confirmed that the inks possess increased colour strength due to the high pigment concentration, a high degree of gloss and fulfil the high demands of fastness and resistance properties. This especially applies to light fastness (at least level 6 according to DIN 16525), fastness to perspiration and saliva (DIN 53 160) as well as  resistance against silver varnish or solvent mixtures (DIN 16524). In addition, a very good scratch resistance is essential for the processing.

The Zeller+Gmelin-group with it’s parent company in Eislingen has been involved with UV-curing of printing inks and lacquers since 1970. The printing inks division of the company concentrates on the development and production of radiation curing ink systems and consequently this specialist ink manufacturer is the market leader in satisfying applications where this special knowledge is particularly important. Various market segments in the field of packaging fall into this category such as adhesive labels, moulded containers (cups, tubes, etc.) and metal packaging as well as direct mailings and other specialist products printing.

For conventional offset and dry offset printing of lacquered and unlacquered metal sheets Zeller+Gmelin offer the Eurapid O3 series which is an oxidation drying ink system.

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