Stone has long been one of the main materials in buildings. Today, building stones are categorized into artificial and natural. Nevertheless, a stone facade is usually a thin stone that is usually extracted from open-pit mines and in the form of blocks. The block needs to be processed in different steps to be converted into a stone facade. In the stone cutting industry, how the stone is extracted and processed is of great importance in the beauty and value of the stone facade. If you wish to learn more about the differences between the artificial and natural stone facade, how the natural stones are extracted, processed, and cut, stay with us.
What you will read in this article:
- The comparison between the artificial and natural stone facade
- Natural stone extraction
- Natural stone facade extraction method
- Natural stone process
- Waterjet stone cutting
Natural or artificial stone facade?
Today, building stones are categorized into two main groups. Natural stones and manufactured or artificial stones (also called stone-clad). Although the artificial stone industry has significantly grown in years and now is the main rival for the natural stone, it is not a sufficient replacement for it yet.
What is the natural stone?
Natural stone is directly extracted from nature without having any materials added or removed. The color you see on the natural stones are its natural shadows, and there are no materials added. Depending on the manufacturer, the stone form could be in the original form or cut in a way the customer prefers.
What is the artificial stone?
Another type of stone is the artificial stone. As mentioned before, there are different names for this stone, which might seem a bit confusing at first sight. To rapidly review, manufactured stone, artificial stone, stone-clad, and cultured stone all have the same meaning: a stone produced by humans. Manufactured stones are basically engineered stones aimed at mimicking the real stones. Cement, aggregates, and iron oxide are mixed and processed until a structure similar to the natural stone is obtained.
The choice between natural stones and those produced by humans, ultimately, depends on your project. For example, if your design needs higher originality and uniqueness, the best choice would be the natural stone. Furthermore, artificial stones are not comparable with natural stones in terms of resistance and strength. Therefore, the main stones used in the building are natural stones.
Natural stone extraction
Natural stones are extracted from the mine walls in the form of large blocks. Then, the manufacturer divides these blocks into other forms. The cutting of these stones isperformed with the help of a saw.
As mentioned, the natural stone must be extracted with precision and preferably in the form of large blocks. Therefore, the first step is to extract the “primary block,” which is a large piece of stone that is separated from mine walls. This is often done by drilling, blasting, and/or sawing. Depending on the stone type, the initial size of a primary block could be more than 1000 m3 and 2700 tons.
During the drilling and blasting process, the important point is that the extraction process must not shred the stone. To prevent this from happening, first, using a drill, a set of holes are created on the main stone to determine the main cutting line. Blasting some stones are easier than others; therefore, the distance between the drill holes should be accordingly set. When extracting stone facades, the use of blasting materials should be restricted as much as possible. Using dynamite is prohibited in some countries. Gunpowder was formerly used in blasting. However, there are highly specialized blasting materials, and numerous explosive fuses are available that facilitate the operation. The blasting method should usually be chosen according to the stone type.
Natural stone facade extraction method
The extraction of stone facade blocks is uniquely sensitive, and the quality of the natural stone must be maintained during the extraction process. There are different ways to do so, including cutting stones by stone cutting machines using cutting discs or circular mills and wire saws, which is mainly used to extract soft and moderately-hard stones, such as marble stone, limestone, and dolomite shell. When extracting stones, drilling stonecutting units could also be used. The methods of destruction of rocks by impact include a drill-hole and shock-cut, and methods of explosion destruction are performed by drilling and blasting method, which is used mainly for the extraction of hard rocks.
Methods for thermal destruction of stones include thermal jet, which is used to extractthe stone block containing quartz. Because in a tense situation, high temperatures rapidly subside. Using this method, stone blocks are directly cut in certain sizes using thermal stonecutting tools, which expels a gas jet with high temperature at an ultrasonic speed.
Nowadays, the most common method of extracting stone from mines is cutting the primary block using a wire saw. The diamond wire cables pass through the holes created by the drill and, in the next step, make large cuts by tightening the wire while sawing. This method of sawing is usually the only method of extracting marble stone blocks and limestone. For this type of stone, chain saws and sword saws could also be used. Even different hard stones could be extracted using a wire saw; however, in most cases, only one or two blocks could be extracted this way, and other blocks must be blasted.
After loosening the primary block from the mine, using drilling/ blasting, sawing, or inserting wedge in the created holes, the block could be divided into smaller pieces. In the stonecutting industry, primary blocks are usually small.
When formed in the right way, the blocks are ready to be transported to the closest factory. If they are supposed to be traded in international markets, fastidious quality standards must be met. Blocks must be in the form of a rectangle. Moreover, they must be intact and without any cracks because they might turn into larger cracks during the processings.
The sold blocks must be homogeneous in terms of color and structure and not contain color stains. The deposits of natural stone usually contain multiple cracks and other defects. Therefore, it is not unexpected that only a few are provided in the standard market.
The steps of stone facade processing
What is stone processing? Stone processing is a series of processing operations that result in stones with a certain shape and size, and its surface reaches a certain texture. Stone processing steps are:
- Approximate processing of stone facade form and size
- Accurate processing of stone facade form and size
- Processing of stone texture
Modern stonecutting workshops are experts in manufacturing products with moderate to high hardness and natural stone. Edging and grinding of stones with different hardness is performed in different steps. The processing steps of hard stone plates are sawing, edging, and grinding. In contrast, the steps for soft stones are sawing, edging, and ultimately, grinding. Regarding soft stones, it will be sawing and edging. Given that in general, some 90% of materials produced from natural stone are stone facades, most stonecutting companies use the most common processing method, which is based on sawing processes.
In the stonecutting industry, how the stone façade is processed and cut has a significant effect on the quality and price. Slate plates are divided over and over along their cleavage lines. In fact, the distance between these lines determines the thickness of the slab. After cleaving along the cleavage line, the stone surface could remain intact.
Cutting the stone block is usually performed using a saw. There are different types of natural stone saws that can be ordered. These include diamond saw blades, band saws (or frame saws) that have a number of parallel and straight saw blades, as well as circular saws in various sizes. Today, advanced natural stone sawing methods are using modern technologies, which include advanced assembly line control system.
After sawing the stones, it is time to polish their surfaces. To do so, a polisher would be used. For this purpose, large materials are used first and then continued with fine abrasives until a shining surface is obtained. This way, the natural color and texture of the stone would be improved. Moreover, different tools could be used to create a smooth surface. Including scanning, sandblasting, or heat and flame treatment. The flame treatment process would lead to smaller crusts of stones due to increased shedding of some mineral materials, mainly quartz. Fire refining is usually performed in the polishing of granite plates, which are used in open spaces (surfaces or facades)
Ultimately, it is time to cut the polished stones in desired sizes. Nowadays, there are modern methods for stonecutting that minimize the wastes, and by cutting in high precision, guarantee the obtained stone quality. The method is used by most stonecutting factories of Tehran, Isfahan, and Koohestan.
Using waterjet in stonecutting
As mentioned, there are numerous methods for polishing and cutting stones in the stonecutting industry. One of the very modern and effective methods is the use of water pressure to cut stones, which is otherwise known as waterjet cutting. Using this method leads to great benefits such as environmental protection and increased accuracy, and decreased waste. You can visit The importance of waterjet cut in stone cutting industry and stone facade for further information.
The Tra-Onyx Co. is one of the leading manufacturers in the production of various marble stones and other types of building and facade stones, which uses up-to-date technologies, such as waterjet stonecutting, provides customers with quality stones in their desired pattern and size.