Expert glassmaker working toward greater technology gains

(This is a sample article from the latest issue)


Sven-Roger Kahl fell in love with glass and its endless possibilities at the age of 12. Now Manager of Furnace Operations and Innovations Group for Ardagh Group, Glass – Europe, he spoke exclusively to Glass Worldwide about highlights from an illustrious career in the industry, including his involvement with GlassTrend as an Advisory Board member.

As Manager of Furnace Operations for Ardagh Group’s European glass container business, Sven-Roger Kahl and his nine-strong team of experts are responsible for the glass melting process at 20 plants throughout the continent, involving facilities in Denmark, Germany, Italy, the Netherlands, Poland, Sweden and the UK. This work begins with the specification and selection of raw materials, the definition of glass compositions and the delivery of plant support for furnace operations. Central laboratory, furnace start-up and tuning specialists are also important members of the team.

Among the most rewarding aspects of the role is the ability to combine experience and knowledge to avoid or solve problems, ensuring that manufacturing sites continue to run at optimal efficiency levels. “It is possible to improve yourself and your knowledge every single day” the glass packaging industry stalwart explains, while emphasising that it can be challenging to convince colleagues that things can and must change. “Sometimes, it is difficult to be patient and wait for an adjustment to work out. Especially when we lose production and everybody is keen to get back to packing, it is difficult to wait and give the process the necessary time to stabilise.

Melting technology focus

Born in Leipzig, Germany, Sven-Roger Kahl attended university and gained an MSc in glass technology in Moscow. His first job was as a Furnace Operator in eastern Germany for Lausitzer Expert glassmaker working toward greater technology gains Sven-Roger Kahl fell in love with glass and its endless possibilities at the age of 12. Now Manager of Furnace Operations and Innovations Group for Ardagh Group, Glass – Europe, he spoke exclusively to Glass Worldwide about highlights from an illustrious career in the industry, including his involvement with GlassTrend as an Advisory Board member. Glaswerke Weisswasser, working shifts, before making his way up to Production Manager for the site within two years. In 1992, Mr Kahl joined the glass container industry and worked in quality control, forming and cold end inspection functions for Gerresheimer Glas and Glashütte Budenheim, before becoming Furnace Manager at Heinz Glas in 1996. Since then, his career has been dedicated to melting furnaces and glass technology, based in the Netherlands for the former PLM Glasindustrie Dongen, then Rexam and now Ardagh Group business.


I fell in love with glass and its endless possibilities at the age of 12 after reading my first book about glass and glassmaking” he recalls. “To this day, I have never regretted my choice because every day brings something new. I am still impressed by the material and its possibilities! We take glass for granted but very few people realise how much our standard of living and the products around us are based on the availability of glass.

Among the key individuals to have influenced Mr Kahl’s glass industry career is Ruud Beerkens, whose comprehensive knowledge and network within the glass industry are described as inspirational. Ruud Beerkens was a Senior Scientist and Professor of Glass Technology at Eindhoven University, TNO Glass Group and CelSian Glass & Solar. He was one of the founders of GlassTrend and retired in 2014. “In addition, I’ve been privileged to work with colleagues who have worked in multiple departments, so that they could oversee the entire process, without necessarily being a specialist in more than one area. Their holistic approach to solving problems in the process and in projects provided me with a good example to follow.

Notable achievements

In almost every area, Ardagh Group is a standards-driven organisation, so the successful standardisation of glass chemistry across Europe by Sven-Roger Kahl’s team ranks as one of his greatest achievements. Another is the improvement of emissions during furnace repairs, starting from modelling, through furnace design, start-up and tuning. “It was a lot of work that also involved liaising with external partners but the end result was even better than we had hoped for” he says.

I enjoy being part of Ardagh Group’s global Innovation Team and was proud to be part of the project team that successfully developed the award-winning Absolut Originality bottle, in partnership with the customer.

In Europe, Ardagh Group’s glassmaking network extends from near Glasgow in the west to Warsaw in the east, Gothenburg in the north and Rome in the south. Glass bottles and jars are produced via a combination of BB, PB and NNPB processes, in 10 different colours.

Under the direction of Sven-Roger Kahl, the Furnace Operations team comprises nine people, based in Germany, the UK, the Netherlands and Sweden. Four people, including SvenRoger, travel from site to site, while the others are based at the central laboratory and other locations.

Current projects include the further implementation of advanced control systems, plus a glass chemistry standardisation that also involves Ardagh plants in the USA. In addition, daily routines include the provision of necessary chemical analyses for glass and raw materials so that plants can control and stabilise their processes.

Close co-operation is essential

As a key service provider to Ardagh’s glass manufacturing facilities, the Furnace Operations team co-operates closely with individual factory personnel and colleagues within the Central Technical Services organisation, such as Furnace Maintenance and Furnace Design. Any raw material issues are solved together with the supply chain, the team taking care of technical questions, while others handle commercial implications.

Because Ardagh Group operates across two continents and multiple countries, close co-operation with suppliers is considered essential. “We want to improve and develop our business together, for the mutual benefit of all partners” Sven-Roger Kahl explains. When selecting external suppliers to support Ardagh investments, for example, the company looks for the best value for money. Its normal procedure is to create an Invitation To Tender (ITT) and send it to potential suppliers. Decisions are then based on the package offered.


Mr Kahl acknowledges that certain elements of the glass container production process are in greater need of development solutions than others, including the adoption of plant-wide Industry 4.0 technologies. “While some parts of the process will be more difficult to apply it to initially, this is just a question of time and development” he suggests. “In particular, however, the glass container industry should place special emphasis on understanding more about the surface and the surface defects of a container; this is what causes breakages and stops us using the full potential of the material in terms of strength.”

Another area for special attention relates to the harnessing of heat extracted from the glass in the forming machine. “We use a considerable amount of energy to heat the glass up to forming temperatures and then spend more energy cooling the glass down… we need to recover and harness the heat from the cooling process.”

Towards CO2 neutrality

Following every furnace repair, Ardagh Group is improving its CO2 footprint but every day, the glassmaker is evaluating opportunities to minimise its energy consumption. According to Sven-Roger Kahl, to achieve this goal, the company applies advanced control techniques and uses as much recycled cullet as possible within the limits of quality, availability and cost. “For glass manufacturing that complies with the Paris Agreement, new technologies must be developed by the whole industry, with co-operation and input from organisations like FEVE and GlassTrend” he explains. “In terms of national initiatives, we also participate in the development and realisation of roadmaps and other initiatives. CO₂ objectives and improvement programmes are part of our sustainability strategy.”

Where available and depending on the cost of alternative energy sources, fossil fuels will be replaced by electricity and/or renewable sources. “The timeframe is two more furnace repairs before we must meet the EU 2050 target for CO2 reduction, so time is ticking to work on such unanswered questions as fuel availability, combustion and flame properties and process control” Mr Kahl warns.

Industry-wide responsibilities

For the past decade, Sven-Roger Kahl has been Ardagh’s representative on the Advisory Board at GlassTrend, an international consortium of industrial glass producers, suppliers, research institutes and other partners operating in the field of glass production. He confirms that membership of this organisation provides a valuable opportunity to participate in research projects, where the industry has significant influence on the subject and direction of research. Other benefits include the chance to participate in regular, high quality workshops and networking opportunities with fellow glassmakers, suppliers, universities and research institutes.

The Advisory Board has considerable theoretical knowledge, combined with direct input from the industry” says Mr Kahl. “This combination allows us to develop research topics and projects that have practical value and are highly relevant to the industry. Within GlassTrend, there is considerable applied research that has a direct impact on the industry. For applied research, GlassTrend sets trends and directions.”

Elsewhere, Sven-Roger Kahl is Chairman of the NCNG, a Dutch foundation that supports training and research for the glass industry and within FEVE, he is a member of the Innovations working group, representing Ardagh Group. He also participates in FEVE’s Food Contact Materials working group and in the P&E Committee, both for Ardagh and the Netherlands.


Looking to the future

Having spent the vast majority of his career in the European glass packaging industry, Sven-Roger Kahl remains confident that glass, like no other material, maximises the premium quality of products, while also combining inertness, transparency, variation in design and sustainability. “What we as an industry need to overcome is the potential risk of breakage, however, as well as the assumption that glass is a commodity product. We need to realise that our competition is not so much other glassmakers but the producers of composite materials made up of multiple layers” he concludes. “From my (not fully objective) point of view, glass is superior to all other materials!

Further Information: 

Ardagh Group, Glass – Europe,
Dongen, the Netherlands
tel: +31 135 79 29 11