A History of Swiss Aluminium
The components of Ville Kokkonen’s lounge chair. (image: Ville Kokkonen).
Europe’s aluminium industry was born in Neuhausen am Rheinfall, a Swiss town in Schaffhausen, the country’s northernmost canton. It was here that the Aluminium Industrie Aktien Gesellschaft established its first production facility in the late 1880s, drawing power from the nearby Rhine Falls, Europe’s most powerful waterfall. “So,” explains Moritz Schmid, a designer based in Bern, “there is a history of aluminium use in Swiss design and industry.”
As a result of the country’s mountainous geography and lack of other natural energy sources, Switzerland’s electricity sector is heavily reliant upon hydroelectric power. Today, Switzerland operates 638 hydroelectric power plants, which account for 59.9 per cent of the nation’s total domestic electricity production. The remaining electricity is largely generated by four nuclear reactors, although these are not expected to be replaced at the end of their lifespan: a fifth reactor, Kernkraftwerk Mühleberg, was shut down in December 2019. Now, following a 2017 referendum, the country will prioritise the development of renewable energy sources, likely deepening Switzerland’s dependence on hydropower. For the aluminium industry, this energy mix has traditionally been a boon. In comparison to fossil fuels, hydropower is a renewable source of energy – albeit not devoid of greenhouse gas emissions – and represents one of the more ecologically responsible forms of powering the metal’s primary production: a notoriously energy-intensive process.
Kokkonen’s aluminium lounge chair, cast by Switzerland’s Christenguss foundry (image: Ville Kokkonen).
To create a tonne of aluminium requires somewhere between 13,000 and 16,000 kWh of electricity. Although aluminium is the most abundant metal in the Earth’s crust, representing 8.1 per cent of its composition, it is typically only found bonded within minerals such as bauxite and cryolite. In order to obtain pure metal, therefore, industrial smelters employ the Hall-Héroult process, which dissolves aluminium oxides in molten cryolite before electrolytically reducing the mixture to generate aluminium. To put Hall-Héroult’s energy demands in context, Australia’s national CSIRO research agency estimates that production of a tonne of steel requires an embodied energy of 22.7 GJ. Hall-Héroult and its associated processes run to around 211 GJ – almost 10 times as much. “So making aluminium in Switzerland made sense historically because of hydropower,” says Schmid, particularly given that this enabled the country, which has few mineral resources, to adopt aluminium as a quasi-national material.
Although Switzerland is no longer a major producer of aluminium, its history in the field has become a pet topic for Schmid and his collaborator Ville Kokkonen, a Swiss-based Finnish designer. “We’ve been looking into the history of aluminium in furniture, at least in terms of our immediate surroundings,” Schmid begins.
“Because people tend to just think of Vitra when it comes to Swiss furniture design,” Kokkonen continues, “but Switzerland actually has a not so well-known, but really quite interesting, history in design.”
Moritz Schmid’s aluminium dining chair, cast by Christenguss (image: Rasmus Norlander).
There is, Kokkonen notes, the history of Wohnbedarf, a modern furniture manufacturer founded in 1931 by Werner Max Moser, Sigfried Giedion and Rudolf Graber. Wohnbedarf’s debut collection featured pieces by Wilhelm Kienzle, Werner Max Moser, Flora and Rudolf Steiger, and Alvar Aalto, while it also commissioned graphic design by Max Bill and showrooms from Marcel Breuer and Robert Winkler. “And of course there’s everything that Le Corbusier did here too,” adds Kokkonen. But 20th-century Swiss design history, the pair explain, particularly comes alive in relation to aluminium.
“There are, of course, the famous works,” explains Schmid, citing Swiss designer Hans Coray’s 1938 Landi chair. The Landi features a perforated, pressed aluminium seat that nestles between two bent aluminium legs, a design which pioneered the three-dimensional shell form that would later be adopted in plastic by designers such as Charles and Ray Eames. The Landi was developed for the 1939 Schweizerische Landesausstellung national exhibition, with 1,500 units created by the manufacturer Blattmann Schweiz AG to be scattered around the exhibition grounds and the shores of Lake Zürich. A newspaper report at the time described how Coray’s “subtly gleaming silver chairs can be carried wherever our desire leads us, as easily as a newspaper or a book”, and although the Landi eventually drifted from production, its enduring appeal saw it re-editioned in 2016 under the auspices of Vitra. The Landi, Vitra’s chairman emeritus Rolf Fehlbaum explained at the time, was a “masterstroke” of furniture design, which “comes from Switzerland and represents something eminently Swiss”. To Fehlbaum, “[the] first aluminium facilities in Europe were at the Rhine Waterfalls. In this respect, aluminium was a modern, Swiss material.”
Schmid’s aluminium dining chair with an orange detail (image: Rasmus Norlander).
“The Landi is a very important piece,” continues Schmid, “but there are many lesser known ones too.” There is, for example, Max Ernst Haefeli’s Elektron chair, which was designed for the German Werkbund in Stuttgart-Weissenhof’s 1927 Die Wohnung exhibition. Haefeli developed a system for the show that relied upon structural elements produced using a castaluminium alloy called Elektron, which he subsequently paired with plywood elements to create an assortment of furniture typologies, including functional, attractive seating. “The Elektron,” Schmid notes, “was one of the world’s first pieces of furniture with aluminium components”. Kokkonen and Schmid further cite Marcel Breuer’s 1097 aluminium lounge chair, designed for the Alliance Aluminium Compagnie’s 1933 Concours international du meilleur siège en aluminium – an aluminium furniture competition that Breuer’s design triumphed in after being selected by a jury containing Sigfried Giedion and Walter Gropius. “And we should also mention Lehni,” Schmid adds. “It’s a company that has strong roots in Swiss design history and which produced several works in sheet aluminium with Donald Judd – very strong pieces, but not well known.”
“It is,” Kokkonen summarises, “an incredible past,” but the present realities of aluminium furniture are perhaps less glorious. Bar notable exceptions such as Emeco’s Navy chair and Herman Miller’s Eames Aluminum Group, aluminium is relatively underutilised within contemporary furniture design, “but it’s a material that is actually very appropriate in use,” Kokkonen explains. Functionally, aluminium is blessed with a number of properties that render it suitable for furniture design. The material is lightweight and lends itself readily to casting, machining and forming. Despite this malleability, it is strong and corrosion resistant, ensuring that its forms are long-lasting and durable. Aluminium is also recyclable, with use of recycled (as opposed to primary) metal offering somewhere between a 90 and 95 per cent reduction in energy consumption during production. Moreover, each time the metal is recycled, there is little degradation in performance. “You have an almost 99 per cent perfection in quality [from recycling],” Kokkonen notes, with this circularity resulting in a number of recent design ventures. Emeco, for instance, began measuring its carbon footprint in 2020, noting in its sustainability report from the same year that its commitment to using a minimum of 80 per cent recycled material in its aluminium products “means our footprint is significantly smaller than comparable products made from virgin materials”; Swedish furniture brand Hem has launched the T Shelf (2022), an extruded shelving system designed by Formafantasma using recycled aluminium; and Apple has made various commitments to produce its components from 100 per cent recycled aluminium, writing in 2019 that the company hoped to move towards “a future where we no longer need to mine precious materials from the Earth to make our products”.
“We talk about these issues a lot,” says Kokkonen, “particularly in the Swiss context where working with aluminium can be slightly more green.” Although their interest in aluminium may have been longstanding (“I’ve been working on extrusion profiles for years,” Kokkonen notes), the pair’s recent discussions around the material stemmed from a particular commission. In autumn 2019, they began speaking to Heinz Caflisch, an architect and designer who founded the Okro design gallery in Chur, east Switzerland, in 2014. “There isn’t really a design gallery scene outside of Basel in Switzerland,” says Kokkonen, “but Heinz has started up with the idea of trying to do something proper in design.” Schmid had already worked with the gallery in 2019, launching both Hoist, a curtain system that can be gathered vertically, and Duo, a selection of works formed from overlapping green and clear glass plates. Okro’s proposed project with Kokkonen and Schmid, however, was to take a different direction. “Heinz was interested in not just editing pieces, but also making connections between designers and industry,” Schmid explains.
While previous projects from Okro – predominantly executed by designers based in Switzerland such as Marie Schumann and Dimitri Bähler – had manifested as straightforward objects, it was determined that any works created by Schmid and Kokkonen would emerge from a dedicated industrial research project. “Instead of just doing an object, it was felt that it should be a deeper collaboration with an industrial partner,” Kokkonen explains. “The gallery wanted to do something with a material-specific producer. In this case, that material was cast aluminium.”
Although there are multiple methods of casting, some of which are more technologically complex than others, the root of the process is simple: molten material is poured or forced into a mould and allowed to cool into shape. “It’s a centuries-old method,” explains Kokkonen, who adds that the final form their research into the technique was to take remained uncertain when beginning the process. Although the pair hoped to design furniture as part of the Swiss aluminium tradition, they wanted to tailor any objects they created to the demands of the casting process. “Aluminium has been used in different ways in the past: as a sheet material or as an extrusion,” says Kokkonen, “but we wanted to see the possibilities of what could be done [with casting] before nailing down a particular typology.” As such, Caflisch paired Kokkonen and Schmid with Christenguss, a family-run foundry in Bergdietikon, north Switzerland, which specialises in small-batch, high-complexity sand castings of copper and aluminium alloys.
In sand casting, molten metal is poured into a cavity formed within a sand mould – a comparatively low-cost means of mould making when compared to other technologies such as die casting. At Christenguss, an initial mould is milled from a block of epoxy that provides a positive of the finished cast, from which a negative can then be taken using a mixture of sand, natural binder and water. In its basic conception, sand casting is one of the simpler casting techniques (the designer Max Lamb’s 2006 project Pewter Stool used a version of the technique that could be produced on a beach in Cornwall) but its industrialised form is highly skilled and an increasing rarity in many European countries. “There are not so many foundries left in Switzerland,” Schmid explains. “It’s a really old way of working and there are issues of high salary costs [within European industry].” Christenguss is well aware of this. The company was founded in 1923 by Fritz Christen and is today led by a fourth-generation member of the same family, Florian. Although the foundry works with companies of all scales, the bulk of its output revolves around casting machine parts for engines and similar applications. “It’s heavy industry and those who haven’t found their niche or fully optimised mass production are having a tough time,” says Christen, who took over the foundry from his father Theo. “We’re in Switzerland, so we can’t differentiate ourselves through pricing. The only way we can compete is through complexity.”
The connection between the two components of Schmid’s cast seat shell (image: Rasmus Norlander).
When Christen was appointed CEO of Christenguss in 2012, the foundry set out to modernise its production capabilities. Automatic sand processing was introduced in the foundry in 2013 and its compressed-air supply was upgraded in the same year, followed by an induction oven system to melt down metals two years later. Yet alongside these initial changes, a more radical adjustment to Christenguss’s operations was also being discussed. “Regardless of what medium you work in, the next step up in complexity is 3D printing,” Christen explains. In order to carve out a niche for itself, the foundry knew that it wished to move into 3D printing, but the precise form which the technology was to take remained up for debate. “We had to decide,” says Christen, “whether we were going to go straight into 3D printing metal, or just 3D print our sand moulds, which we could then flow back into our conventional production lines. Ultimately, the latter represented the more organic way.” In 2016, the foundry’s first 3D printer was installed.
Printing its sand moulds gives Christenguss two chief advantages over its competitors. Working directly from CAD files, the opportunity to prototype – and the speed with which this process can take place – is vastly increased. “It brings prototyping to a different level,” notes Kokkonen. “You can quickly try out different shapes, sizes, volumes and wall thicknesses, without investing in a final tool.” Alongside this increased pace, the technology allows for the creation of more intricate castings than would be possible using a conventional mould, markedly increasing the range of the foundry’s output. Yet this increased complexity brings with it the need for handcraft. “People have this romantic idea with 3D printing that you just take the thing out of the machine and it’s there,” explains Christen. “But it actually comes with a whole bunch of processes. You have to clean the support structures where loose sand has stuck to the mould, for instance.” This cleaning, he notes, is highly challenging, particularly with intricate moulds. “Sand is very abrasive, so when you blow or brush it off you have to be very soft and gentle or else you compromise your technical measurements and tolerances. You can’t just get anyone to do that – they have to have an eye for it.”
Another challenge of 3D printing sand moulds is that it costs more. Whereas a conventional mould can be made using multiple grades of sand, 3D printing requires extremely fine, standardised particles. “We use quartz sand and, conventionally, we have a little more room when it comes to grain sizes,” says Christen. “With the 3D printer, that is reduced to one specific size of grain. So that is a cost factor, because that sand is approximately five to six times more expensive than what we use in the regular process.” Further costs arise from the fact that manufacturers of 3D printers require customers to purchase all parts and materials directly from them if they are to extend the warranty on their machines. “Everything on this thing is just ridiculously expensive,” says Christen, “and that’s down to the [3D printer-makers’] business model.” To mitigate this expense, Christenguss operates both 3D-printed and conventionally produced moulds. While the latter is more economical when producing at scale and can satisfy many conventional casting requirements, 3D-printed moulds come into their own for more specialist applications. “Most technical parts have a very simple outer geometry but a very complex interior,” Christen explains. “For certain cases, we can produce the outer geometry on a conventional machine but print the core to get the inner geometry.”
Some projects, however, are entirely reliant upon printing. In 2017 and 2018, for instance, the foundry partnered with students from ETH Zürich to create Digital Metal and Deep Facade, two projects built around highly complex, sand-cast aluminium elements. The former cast intricate joints that could knit together aluminium tube profiles to create a pavilion structure, while the latter focused on curling ribbons of metal that snaked around one another to build up a building’s fascia. “Those projects pushed 3D printing to the absolute limits,” says Christen, “but we weaned ourselves off [work like that] a little, because we could see what the workload was in comparison to the outcome – it just didn’t match up.” What Christen hoped for instead was a project that could explore the production capabilities of his family firm, while also resulting in a saleable final outcome. In place of casting components to order, could Christenguss produce a customer-facing product? “This had never materialised up to this point because there are artists, and then there are artists/salespeople,” Christen explains. “We were always waiting for that second type of person, which is what Moritz and Ville represented – they’re designers who can tailor things to a market. That was the draw.”
Schmid and Kokkonen’s portfolios eased the process. Schmid, for instance, has created designs for brands such as Kvadrat, Atelier Pfister and Glas Trösch, having founded his studio in 2008 following a tenure within the studio of Alfredo Häberli. Kokkonen, meanwhile, has operated his office since 2004, providing strategic design and product development for companies including Nokia and Iittala, as well as having served as design director for Artek, the celebrated Finnish furniture brand. “From an economical standpoint that was interesting for me, because it suggested they would create something we could develop, produce and sell,” says Christen. In kind, Schmid and Kokkonen would gain access to a highly specialised aluminium production facility that could aid their development of cast furniture components. In so doing, they hoped to explore the potential for designers based in Europe to expand their industrial repertoire by branching out from traditional design producers and overseas manufacturing facilities, and instead work with small and medium-sized enterprises (SMEs) in their countries of residence.
“SMEs are their own sector of industrial production, but they often don’t do any commodity goods or customer-focused products,” says Kokkonen. While such companies have considerable expertise and technical proficiency, he notes, there are typically few opportunities for them to develop new outlets for their skill. Christen agrees. “Only a fraction of people actually know that there are still foundries in Switzerland,” he says, “but I think they’re starting to become interested again, and seeing the necessity of having these industries domestically.” Although Christenguss has historically worked to produce specialist industrial castings, there is little reason that its facilities cannot also serve designers and companies hoping to produce consumer objects – particularly gallery-based works that can carry higher price tags than their more mass-produced equivalents. “A tendency we’re now seeing in the markets, and what Ville and Moritz picked up on, is the excitement of casting and production,” says Christen. “For the last 20 years, the default was that nobody cared where design came from, but with the circular economy and reducing carbon footprints, many people are now coming back to their respective continents and trying to find producers. They want the whole picture – from designing the parts through to the final production.”
This is where Schmid and Kokkonen felt they could make a difference, anchoring Christenguss’s production to a contemporary consumer object “Visiting factories is always fascinating, because you get to really look at it from their perspective,” says Kokkonen. “What would suit them and get them motivated and interested?” With this in mind, the two designers began to investigate furniture elements that could be developed through Christenguss’s 3D-printed moulds, with each designer conscious of the need to balance the process’s benefits against their desire to create pieces that were economically viable and suitable for the market. “3D-printing technology opens up a lot of possibilities, but we wanted to break it down to find something that made sense,” explains Schmid. Kokkonen is similarly wary of the trap of pursuing complexity for complexity’s sake. “The goal was not to go for the craziest shape possible,” he says. “If you do that, the price becomes super expensive because it’s laborious to work with moulds that delicate.” In this respect, the process began to differentiate itself from the previous collaborations with ETH. “I had initially expected their work to be more towards the actual 3D printing being pushed to its limits,” acknowledges Christen, “but we needed to realise that these guys have a different perspective, and see things through another lens, which is why they’re the designers and we’re not.” He pauses. “Actually, we suck at designing. We can produce pretty much whatever you want, but we can’t design anything.”
Driven by the constraints they had set themselves, Schmid and Kokkonen began to investigate separate typologies. Schmid, for example, focused on creating a dining chair, and the possibility of casting an aluminium seat shell that could be flat-packed for delivery. “Printing and casting give you opportunities for complexity, but I wanted to ensure that if I were to develop a cast piece, all the chair’s complexity could be contained within that casting,” he says, adding that he subsequently created his chair’s legs from a standard aluminium profile. The cast shell itself, meanwhile, was broken down into two separate castings: a seat and a backrest that could be connected to make the chair. “Casting in aluminium, which has more strength than plastic, opened up new possibilities to work with that shell typology,” he says. “So you could use that seat and four legs as a classic stool, but the backrest then completes it to form a chair – it adds a few extra centimetres at the back because of the radius it has.”
“Moritz’s design is an exploration of how far design can push us,” acknowledges Christen. “He was really trying to push the radiuses and shapes, and there are some undercuts in there which aren’t possible with a conventional mould.” The two castings in Schmid’s chair curve to accommodate one another, for example, before being secured with a single oversized screw – a technical element that, on at least one version of the chair, has been anodised in a zesty orange as an aesthetic flourish to highlight the construction methodology of his design. “It was important to find a nice, simple solution to connect the two parts that is understandable to everyone, but which also gifts the chair its character,” he says. “So you have this big screw head, which works because the backrest has been cast to slightly grab under the seat, meaning that it can’t then turn any further.” Although the chair’s 3D mould was reasonably straightforward, Schmid’s design challenged Christenguss’s team with its material demands. “We pushed this chair beyond where theory says it’s safe,” Christen notes, explaining that a cast of this kind would not typically be allowed to drop below a 6mm thickness. “But Moritz’s chair works perfectly fine at just 4mm,” he says, explaining that Schmid drove this reduction process to help limit the design’s weight. “What we’ve ended up with is really, really thin and weighs 4kg,” Schmid explains. “OK, you can’t compare that to the Landi chair [c. 3.4kg], but to other classic chairs I would say it’s quite alright.”
While Schmid pushed at cast aluminium’s functional limits, Kokkonen’s approach was different. “From the very beginning, Ville had the sense that, at some point, you could translate his design from a 3D-printed mould into conventional production,” Christen explains. In place of a dining chair, Kokkonen chose to investigate lounge chairs and, in particular, the opportunity to cast a basic frame structure that might encompass a front and back leg in one pouring. “I was very fond of thinking about a lounge chair as something offering comfort, where weight limitations play a slightly different role to those on a side chair,” he explains. “I wanted to work on a frame in which durability played a big part.” Mindful of the potential for future mass production, Kokkonen favoured the creation of a single mould (although he eventually used two mirrored components to avoid repetition), which would provide the entire structural basis for his subsequent design. “Today, you really want to focus on minimum logistical costs for economic and ecological reasons,” he says, “so I wanted to create a robust component that could be easily flat-packed.”
The resultant frame appears simple, but much like Schmid’s work contains all of the design’s complexity within its casting. Each cast contains a front and back leg, connected by a panel of aluminium that traces the V-shaped geometry of a seat suspended between its two legs. Although Kokkonen’s final casting is simple enough to mean that it could be produced conventionally if desired, 3D printing was used in order to prototype the piece and develop its final form. Initially, for instance, Kokkonen created a hollow, lightweight test version of his structure, before accelerating the design process by shifting into a more solid casting. “But I was surprised by the resultant weight, so I wanted to cut every single centilitre out of it,” he says, with his resulting amendments leaning on weight reduction methods already widely used in industry. At the edge of the casting, for instance, the thickness of the metal increases to provide strength, before thinning out in the centre to generate a kind of I-beam profile. “It gives you a particular tool-like aesthetic that I really like,” says Kokkonen, “which was the principle behind the shape of the frame.” With these castings providing the overarching structure, Kokkonen was free to experiment with the material of the seat that would be suspended between them: while the anodised casting is rough and industrial in tone, this element of the design was a space to introduce a contrasting aesthetic. “I ultimately used bent aluminium for Okro, but you could also use leather or plywood,” he explains. “Something comfortable and luxurious in the centre of the chair, but the edges of the design remain as very industrial structures which are there to support the seat. Any bent sheet material would work as that stabilising structure – you don’t need any extra stretchers in the front or in the back because it’s really rigid.”
Schmid and Kokkonen’s aluminium chairs – cast by Christenguss before being assembled by the designers and exhibited at Okro under the exhibition title Al 13 – offer a reflection on the present realities of production and design in Switzerland. “Usually, Christenguss only makes a component of a larger entity, but we wanted to highlight their wider expertise,” says Kokkonen. “They work with industry, and do extremely complex parts for engines and so forth, but we felt there was more design potential there.” The opportunity to create the Al 13 castings, Schmid observes, is an opportunity for the foundry to rekindle something of the history of Switzerland’s 20th-century aluminium furniture: an opportunity to make a mark alongside Coray’s Landi and Haefeli’s Elektron. “Typically the foundry just have orders to fill, but once we had assembled our chairs, and everyone could finally see them and sit on them, they were so happy,” says Schmid, “which is where it got a bit emotional for all of us.”
This, Christen notes, is the power of the project. “It’s been nice to see that there are things that can be done outside of our usual production,” he says. “We essentially have our own product now. It’s something that we helped to develop, and not just something that a customer approached us with to produce. It’s kind of our baby, you know?” Moving forward, Christenguss can produce the designs in small-batch series according to demand, with the two chairs intended as a testament to the sand casting that makes them possible. “It sparks this sense of industrial romance,” concludes Christen. “It gives you a sense of how aesthetic production can actually be.”
Words Oli Stratford
Photographs Rasmus Norlander
This article was originally published in Disegno #33. To buy the issue, or subscribe to the journal, please visit the online shop.