Manufacturing Process
We ensure only the best for your spaces, which is why our tile manufacturing goes through a lot of processes to maintain the highest standards and obtain the final product.
Raw Materials
Here is how we source our raw material
Our Process
After processing the raw materials, numerous steps take place to obtain the finished product. These include batching, mixing and grinding, spray-drying, forming, drying, glazing and firing. Many of these steps get accomplished using automated equipment.
The amount and type of raw materials determine the body composition of many ceramic products, including tiles. The raw materials also influence the colour of the tile body, which can be either red or white depending on the amount of iron-containing raw materials used. As a result, it is critical to combine the proper amounts to achieve the desired properties. Batch calculations are thus required, which consider the physical and chemical compositions of the raw materials. After determining the appropriate weight for each raw material, the raw materials get mixed together.
After the ingredients are weighed, they get combined in a shell mixer, ribbon mixer, or intensive mixer. A shell mixer is made up of two cylinders connected by a V that rotates to tumble and mix the material. A ribbon mixer employs helical vanes, whereas an intensive mixer uses rapidly rotating ploughs. This step grinds the ingredients, even more, resulting in finer particle size, which improves the forming process.
Water is sometimes required to improve the mixing of a multi-ingredient batch as well as to achieve fine grinding. This is known as wet milling, and it is commonly done with a ball mill. Slurry or slip is the name given to the resulting water-filled mixture. The water is then removed from the slurry by filter pressing (which eliminates 40-50% of the moisture), followed by dry milling.
When using wet milling first, the excess water usually gets removed by spray drying. This entails pumping the slurry to an atomizer, which is made up of a rapidly rotating disc or nozzle. Slip droplets are dried as they are heated by a rising hot air column, resulting in small, free-flowing granules and a powder suitable for forming.
Dry grinding followed by granulation can also be used to prepare tile bodies. Granulation employs a machine that mixes previous dry-ground material with water to form the particles into granules, which then create a powder ready for forming.
Most tiles are formed by dry pressing. In this method, free-flowing powder — containing an organic binder or a lower moisture percentage — flows from a hopper into the forming die. The material is compressed in a steel cavity by steel plungers and then ejected by the bottom plunger. Automated presses with operating pressures as high as 2,500 tons are employed.
The process also consists of several other methods where the tile body is in a wetter, more moldable form. The extrusion plus punching process produces an irregularly shaped tile and thinner tile faster and more economically. It involves compacting a plastic mass in a high-pressure cylinder and forcing the material to flow out of the cylinder into short slugs. These slugs are then punched into one or more tiles using hydraulic or pneumatic punching presses.
- Ram pressing
Heavily profile tiles often deploy ram pressing, wherein extruded slugs of the tile body get pressed between two halves of a hard or porous mould mounted in a hydraulic press. The formed part first gets removed by applying a vacuum to the top half of the mould to free it from the bottom half, followed by forcing air through the top half to free the top part. Moreover, the formed part may also require excess material removal and additional finishing.
- Pressure glazing
Pressure glazing is a recently developed process that combines glazing and shaping simultaneously by pressing the glaze (in spray-dried powder form) directly in the die filled with the tile body powder. Its advantages include the elimination of glazing lines and glazing waste material (sludge) that gets produced with the conventional method.
After forming, ceramic tile must usually be dried (at high relative humidity), especially if a wet method is used. Drying removes water at a slow enough rate to prevent shrinkage cracks, which can take several days. Continuous or tunnel dryers, heated with gas or oil, infrared lamps, or microwave energy are used. Infrared drying is ideal for thin tiles, whereas microwave drying is ideal for thicker tiles. Another method, impulse drying, employs short bursts of hot air flowing transversely rather than continuously in the material flow direction.
The glaze gets prepared in the same way as the tile body. Following the calculation of a batch formulation, the raw materials are weighed, mixed, and dry or wet milled. The milled glazes are then applied using one of several methods. The glaze is fed through a rotating disc that flings or throws it onto the tile in centrifugal glazing or discing. A stream of glaze falls onto the tile as it passes underneath on a conveyor in the bell/waterfall method. Sometimes, the glaze gets simply sprayed on. Screen printing on, under, or between wet glazed tile is used for multiple glaze applications. The glaze is forced through a screen using a rubber squeegee or other device in this process.
Dry glazing is another option that gets employed. Powders, crushed frits (glass materials), and granulated glazes are applied to a wet-glazed tile surface. After firing, the glaze particles meld together to form a surface resembling granite.
After glazing, the tiles must be heated intensely to strengthen them and achieve the desired porosity. For firing the tiles, two types of ovens, or kilns, are used. Wall tile, or tile prepared by dry grinding rather than wet milling, typically necessitates a two-step process. Before glazing, the tile goes through a low-temperature firing called bisque firing. This step removes the volatiles from the material as well as the majority (if not all) of the shrinkage.
The body and glaze are then fired together in a technique known as glost firing. Both firing processes take place in a tunnel or continuous kiln, which consists of a chamber through which the ware is slowly moved on a conveyor on refractory batts (high-temperature-resistant shelves) or in saggers (containers). Tunnel kiln firing can take two to three days, with temperatures around 2,372 degrees Fahrenheit (1,300 degrees Celsius).
Roller kilns are usually used for tiles that only require a single firing — typically tiles prepared by wet milling. These kilns use a roller conveyor to transport the wares and do not require kiln furniture such as batts or saggers. Roller kiln firing times can be as short as 60 minutes, with temperatures reaching 2,102 degrees Fahrenheit (1,150 degrees Celsius) or higher.
The Final Output
