Essentially, the same raw materials have been used to produce high-quality porcelain from primeval times to the present day: kaolin, clay, feldspar and quartz sand. These materials are delivered by the ton – from European clay and loam pits, especially in Germany, France, the United Kingdom and the Czech Republic – to our production facilities. LAUFEN processes many thousands of tons of these solid materials each year.
and quartz sand
Careful handling of raw materials
This is not mere paying lip service, and can be seen directly in our manufacturing processes. Incorrectly cast pieces are eliminated and returned to the processing cycle. Even items that have already been glazed and fired, but which do not meet our high-quality standards, will not end up on a disposal site, but are finely ground by external partners. This “ceramic powder” is then added to the compounds used for new products. Water is needed to transform these materials extracted from the earth into castable compounds. Surplus water is collected and purified in our in-house treatment plant. It can then be re-used in the production process, after which it will once again be purified.
Extracted from the earth
A brownish-grey, liquid slurry, known as the mass, is formed when the ingredients from the raw material containers and silos are mixed with water – according to precise formulae.
Mixed anew – every day
In principle, processing the mass for manufacturing sanitary ware can be compared with preparing bread or cake dough. In both cases, success will depend on the correct procedure as well as the dosage and mixture of ingredients. Preparing the mass begins by mixing the clays with water as well as electrolytes, which serve as plasticisers. Sieving the clay mass removes particles that have not dissolved. Strong magnets are used to extract ferrous components from the mass.
Mass temperature: 28° Celsius
Beautiful shapes need perfect moulds
The right moulds – a different one for each model – are needed to cast various products such as WCs and washbasins from the slurry. For a simple washbasin, such a mould is not very complicated, but for a WC, with its complex interior, the construction of the mould is a very laborious process. While the simplest plaster moulds consist of two sections, the most complex can feature up to 24 components. Plaster moulds are used for battery casting machines and the hand casting of small batches and complicated items; the plaster extracts moisture from the slurry. For machine pressure casting, synthetic moulds are used.
Larger or smaller numbers of each mould are required for production, since entire series of the same model are manufactured simultaneously, and moulds cannot be used indefinitely. Depending on the model, plaster moulds can be used for 80 to 120 casts. To produce the moulds, a so-called mother mould is first made in the mould studio. This is not so simple, because there can be shrinkage of up to 12 percent when the mould is fired. As the shrinkage is not linear, it is not possible simply to factor in an extra 12 percent when constructing the mould. It takes a great deal of experience and instinct to achieve the right balance.
80 to 120
casts per plaster mould
The mass doesn’t react to every mould the same way
Once a new model has been cast and fired, it is examined and analysed, inside and out, with the greatest precision. Any deviation from the specified design is measured exactly and mapped on the item itself. Experienced mould-makers then painstakingly adapt the mother mould by hand. Another article must then be cast and fired in order to see how the mass reacts to the altered mould. If the result still fails to meet specifications, the mould will be modified again – or as many times as it takes for the end product to conform to all requirements. Only then will the casting moulds for serial production be made, based on the mother mould.
Remixed – every day
Thereafter, the correct dosage of kaolin and so-called hard material components – a powder consisting of feldspar, quartz and shards – is added to the mixture. Once the ingredients have been mixed, the mass is sieved and magnetised once again.
Also known as pourable slurry, the mass is kept moving by an agitator at a temperature of 28 degrees Celsius in large tanks until it is cast. The entire process of preparing the mass lasts approximately 20 hours. A new mass is produced every day to cover the needs of one day’s production.
The SaphirKeramik hand-casting workshop, where Ino countertop washbasins are produced, resembles an artist’s studio.
Think of shrinkage when firing
When cast from traditional materials, double-wall products densify – and thus “shrink” by between 6 and 8 percent. In order to achieve perfect results, this shrinkage must be taken into account from the very beginning. This is more complicated than it seems, because shrinkage is not linear. This is why, unlike SaphirKeramik, casting straight lines from traditional materials presents a considerable challenge.
cast: 1 metre
0.88 metres = 12% shrinkage
Large items – thanks to fine fire clay
By developing fine fire clay in the 1980s, LAUFEN made it possible to produce larger items. Adding refractory, especially fired clay enables us to reduce non-linear shrinkage to below 10 percent, thus giving greater control over the way the mass reacts and allowing the production of ceramic items of more than 1.80 metres in height and 70 kg in weight.
Traditional, conventional casting is the most complex casting process, and is applied when more complex items, very large models and small batches are produced. It requires a great deal of technical skill. Preparing the mould and casting a single piece can take up to 40 minutes. Using this method, an employee will produce approximately 16 to 30 items per day. Pieces manufactured using this method account for between 5 and 10 percent of production.
Battery casting machines are used for the production of large numbers of standard items. To a great extent, the production process is mechanised, but the proportion of craftsmanship required remains high. In this process, there are one or two sprues per day; depending on the level of difficulty, between 30 and 70 articles are produced per employee. 60 to 70 percent of production is manufactured in this way. When products are removed from their moulds, they are still relatively soft. For this reason, they must be handled with care. LAUFEN designed new, internal transport solutions especially for the handling of very heavy, new models such as the free-standing washbasins manufactured in cooperation with Italian design company Alessi.
Putting a hand to it
As soon as articles are taken from their moulds, they will be finished by hand – before they’re even dry. Every single piece is carefully deburred; in other words, rough edges resulting from casting are smoothed. Various apertures, such as washbasin overflows or holes for later installation, are also recut and deburred, and any irregularities adjusted. Only once every item has been hand-finished will it be placed carefully – it is still relatively soft – on the conveying system to dry.
An innovation is revolutionising bathroom design
Broad rims and wide radii are typical characteristics of conventional porcelain sanitary ware. This is due to the materials used. However, in 2013, LAUFEN launched SaphirKeramik. In five years of intensive research and development, an innovative material with special qualities was perfected for industrial application: SaphirKeramik makes it possible to produce thin yet extremely resilient walls, and very narrow radii are no longer a problem. The material is hygienic, very robust and recyclable. Thanks to this innovation, modern designs of the highest quality can be created. Washbasins made of SaphirKeramik are cast both by hand and using the pressure casting process.
The machine pushes the synthetic moulds together, and the mass is automatically pumped into the mould. This pourable slurry is desiccated over the porous synthetic mould at a pressure of 12 to 16 bar. A few minutes later, the moulds split with a hiss and release the cast washbasin. A few finishing touches by hand are still required before the article is placed on the conveyor system to dry. The machine disgorges the new washbasins every twelve to fifteen minutes.
This efficient pressure casting process for washbasins, developed especially by LAUFEN, enables the production of 80 to 120 washbasins per day and employee. Advantages of this method include high-quality surfaces and the little effort involved in manual finishing. Moreover, the synthetic moulds can be used for 20,000 to 25,000 casts. By comparison, a plaster mould used for battery casting produces between 80 and 120 casts.
How the ROBOT handles WCs
It’s fascinating to watch a handling robot at work. The way it removes the pieces from the pressure casting mould and assembles them. The way, while one WC is being cast, it removes and assembles the WC that has just been cast and cleans it with the greatest precision. The way it changes the tools attached to its gripper arms. Moves the heavy components with ease. The robot can handle between 60 and 80 WCs per day. However, when it passes on the finished items, more work by hand is required. Every WC is critically examined by the human eye, and if necessary, given the finishing touches by hand. Only then will the WC, which to a large extent has been manufactured automatically, be placed on the conveyor system to dry.
Almost everywhere, cast WCs, washbasins and other items are constantly in transit, gliding through the production halls as if by magic. But there’s no magic at work here: automated conveyor systems bring the products from one step of the manufacturing process to the next. These automated systems make an important contribution to ensuring that production remains in Central Europe, where staff costs are comparatively high. After casting, the individual components have to be dried. Certain items are simply dried in the warm workshops for about three days. Continuous dryers are faster; at 60 degrees Celsius, humidity is reduced from 15 to 18 percent to 1 percent within four to six hours. For WCs, there are chamber dryers, in which wall-mounted WCs are dried at up to 70 degrees Celsius in 11 and standing WCs in 22 hours. Incidentally, the dryers are heated – à propos sustainability – using waste heat from the tunnel kiln, in which our products are fired at up to 1250 degrees Celsius.
GLAZING seals and beautifies
The glaze embellishes the surface of ceramic products; it forms a cohesive, glass-like layer and makes porcelain even more hygienic. Most of LAUFEN’s products are covered in a white, shiny glaze, but in principle the widest variety of colours is possible, and there are frequent requests for matte glazes.
The vast majority of LAUFEN products – about 95 percent – pass through a fully automated glazing line. All manner of items and models are transported in succession on the conveyor system to the glazing facility. This automatically recognises the product, and all its operations are adjusted to the specific shape of the item in question.
For WCs, LAUFEN has developed an automatic pouring system for glazing the cavities. The liquid glaze is automatically poured into the WC; automatically generated movements ensure that all the necessary surfaces are covered. The next step consists of the robot taking on the task of glazing in a closed chamber. Following the shapes of the model previously identified, it then glazes all the surfaces of the item that are accessible from the outside. Approximately 300 items are glazed per shift.
Special pieces are glazed by hand
A little apart from the industrious robot, hard-working people are doing almost the same job. Complex or very large items are glazed by hand, as are small batches in unusual colours or of rare models. This accounts for approximately 5 percent of production. In these cases, the glaze is applied by hand with a spray gun. This intensive manual work requires experience and sensitivity, for the coat of glaze applied must be consistently between 0.6 and 0.8 millimetres thick.
The glaze only becomes completely smooth when fired
Whether applied by a robot or a human being, the unfired glaze looks slightly uneven, a little like cellulite, but will become completely smooth once fired.
and kiln wagons
After glazing, the unfired articles are placed on firing batts. Ten firing batts consisting of a total of 20 to 25 items are known as a “kiln wagon.” The products are placed in a storage facility until firing, when they are loaded on to the kiln wagons. This is done automatically. The kiln wagons are covered in a layer of refractory bricks on which in turn fireproof ceramic fibre mats are laid, above which the firing batts, which resemble low tables, stand on supports. A seemingly coincidental collection of WCs, urinals, washbasins and other items stands on these batts.
RESIDUAL HUMIDITY IS EXTRACTED
Before items are fired, they are put through a pre-dryer, in which they are heated to temperatures between 100 and 120 degrees Celsius. This extracts any residual humidity. The pre-dryer is heated with the waste heat of the tunnel kiln.
Off to the kiln!
The imposing tunnel kiln is more than 100 metres long. No wonder it’s also very hot next to the kiln, which is heated by natural gas to temperatures of up to 1250 degrees Celsius. One kiln wagon after another rolls very slowly into the tunnel. At any one time, there will be 50 wagons in the kiln, which is heated 24 hours a day. Their journey will take between 20 and 22 hours.
Only firing makes porcelain really hard, robust and ready for use. This process renders the material insoluble in water, and the glaze merges with the porcelain, which contracts – hence the shrinkage of 6 to 8 percent – and thus hardens.
After the firing process, the introduction of air from the workshop via ventilators over a stretch of just under ten metres causes what is known as instant cooling from 1250 down to 650 degrees Celsius. Thereafter, the fired items roll through a cooling zone in which their temperature slowly falls. An important stage is reached at 573 degrees Celsius: quartz inversion. At precisely this temperature, the quartz components in the porcelain undergo a transformation that is important for the consistency of the material.
Through the tunnel at 0.005 km/h
After more than 100 metres and just over 20 hours, the kiln wagons arrive at the end of the tunnel. Having passed through a cooling zone, at 40 degrees Celsius the items are cool to the touch.
with Q-Plus certification
After the fully automated firing process, human eyes and hands are required for control and final assembly. Every single item is thoroughly examined and verified: Are the form and glaze entirely as they should be? Are there defects or flaws? Any imperfections in the assembly surfaces are ground away. Urinals and WCs are checked for flush performance and to ensure that they are impermeable. As far as flush performance is concerned, requirements differ according to the country of destination. Items that pass these tests are allocated to the CQ – commercial quality – category, meaning that they will meet all requirements for daily use for many years.
Items with minor surface defects that will have no adverse effects – either on the durability of the material or its functional capabilities – are sent to be refinished. Imperfect areas in the glaze are touched up, and the items are put through the kiln again.
PERFECTION – one of our FUNDAMENTAL PRINCIPLES
Items with large cracks or other defects that cannot be corrected are categorised as breakages. They are collected and later finely ground down by external partners. The resulting powder is then mixed into the slurry used for new products.
In addition to these final checks, the internal quality inspection department regularly takes spot checks from the entire production to ensure that the articles manufactured meet all technical specifications and comply with regulations. Even prototypes and pilot series are thoroughly scrutinised by the quality control department, because LAUFEN considers perfection – be it in terms of form or workmanship – to be one of its fundamental principles.
Items that have passed all quality controls and thus meet commercial quality criteria are entered in the data collection system and packaged, after which they are transported to the finished goods warehouse. According to the orders placed, the items are then taken from the logistics warehouse and prepared for despatch within Switzerland and abroad.
It has taken up to one week for raw materials extracted from the earth to have been transformed into well-designed, elegant, high-quality sanitary ware – products that over a long lifetime will not only render good service, but will also look wonderful.
once, now, here