Granite belongs to high hardness stone, and its Mohs hardness is about 6, so it is difficult to process. Later, due to the wide application of synthetic diamond tools, granite processing industry developed rapidly and became the most widely used and used natural veneer at present.

Granite has a wide range of applications, whether indoors or outdoors, villas or square buildings, its shadow can be seen everywhere. Among them, granite plate is the most widely used and the most traded product is granite plate.

1. A processing method of granite plate

Granite board is widely used, but there are many kinds of products, such as paving stones, specification boards, small squares, arc boards, corners, lines and so on. However, the main processing methods of granite are not complicated. The basic processing methods include sawing, grinding and polishing, cutting, chiseling, singeing, auxiliary processing and inspection and repair.

1) sawing

Sawing is to cut granite waste into rough plates (generally 20mm or 10mm in thickness) or semi-finished products in strips or blocks with a stone saw. This process is a rough machining process, which has great influence on the yield, plate quality and economic benefits of enterprises.

The main processing equipment in sawing is a special frame-type automatic sanding saw for granite, a multi-blade bidirectional cutting machine, a multi-blade computer-controlled granite cutting machine and a granite circular saw.

2) grinding and polishing

The purpose of grinding and polishing is to further process the sawed wool board to make its thickness, flatness and gloss meet the requirements. This process needs rough grinding and leveling first, and then gradually through semi-fine grinding, fine grinding and polishing, to fully display the color and texture of granite.

The main processing equipment are: automatic multi-head continuous grinder, diamond straightener, bridge grinder, disc grinder, reverse rough grinder and manual grinder.

3) cutting and processing

The cutting process is to cut the rough board or polishing board according to the required specifications and sizes with a cutting machine.

The main processing equipment includes longitudinal multi-blade cutting machine, transverse cutting machine, bridge cutting machine, cantilever cutting machine and manual cutting machine.

4) Chiseling and cutting processing

Chiseling is a traditional processing method. The rough embryo is processed into required products by wedging, chiseling, chopping, trimming, polishing and other methods, and its surface can be pineapple noodles, longan noodles, litchi noodles, natural noodles, mushroom noodles, furrow noodles and the like.

Chiseling, cutting and adding are mainly processed by hand, such as hammer, chopping axe, chisel and chisel. But some processing procedures can be completed by machines. The main equipment includes stone chipper, planer, automatic hammer chipper and automatic sandblasting machine.

5) singeing treatment

Singeing processing, also known as fire processing and spray processing, makes use of the difference of thermal expansion coefficients of different mineral particles that make up granite, so that some particles on its surface thermally expand, crack and fall off with the flame spraying, forming a rough surface pattern with ups and downs. This rough granite slab

Very suitable for floor decoration and outdoor wall decoration in wet places.

The main equipment is granite automatic singeing machine.

6) Auxiliary processing

Auxiliary processing is to polish, chamfer, drill holes, groove milling and edge milling the cut and polished stone as required.

The main processing equipment includes automatic chamfering machine, copying milling machine, thin-wall drilling machine, hand-held diamond circular saw, hand-held polishing machine and so on.

7) Inspection and repair

Natural granite will inevitably have cracks, holes and other defects, and there will inevitably be some bumps and some small defects during processing. Therefore, after the processing is completed, all granite plates need to be inspected. First, it should be cleaned and then dried. Qualified products should be packaged and put into storage, and unqualified products should be picked out first. In the case of meeting the requirements of the order, some granite products with slight defects can be repaired, that is, bonded repair, thus reducing the rejection rate.

Inspection and repair are usually manual operations, but some advanced processing production lines will adopt automatic continuous blowing and repair air dryers.

2. Granite plate processing process

There are four main production lines for processing granite plate products:

Specification plate production line, thin plate production line, rough decorative plate production line, special-shaped plate production line.

1. Processing technology of granite specification plate

The waste is loaded on the scrap car by crane, sent to the working position of frame sand saw by car ferry, sawed into rough plates, then sent to grinding, polishing, cutting and other processes to be processed into smooth plates, and finally inspected, packaged and put into storage.

Main process:

Raw material hoisting → sawing → water washing inspection → rough grinding → fine grinding → fine grinding → polishing → cutting and repairing → inspection and packaging.

2. Processing technology of granite plate

The processing of granite plate is basically completed by automatic processing line, and the process is basically the same as that of specification plate, and the processes are connected by raceway, unloader and turnover machine.

Main process:

Hoisting raw materials → sawing into thin plates → cutting → grinding and polishing → cutting → edging, chamfering, slotting, repairing, cleaning and drying → inspection and packaging.

3. Processing technology of granite rough decorative board

The granite semi-finished blank plate is sent to the automatic roughing machine through the raceway (the cutter head is selected according to the required pattern thickness), and the cutter head chisels out various required coarse decorative patterns according to the predetermined trajectory. If you need a singeing, send it to the automatic singeing machine.

Main process:

Semi-finished blank plate → shaving or singeing → cutting → inspection and packaging.

4. Processing technology of special-shaped plate

According to the user's special requirements for the shape and specifications of granite plates, design and manufacture templates, such as round and oval desktops, oval hole bathroom countertops, flower windows, etc. Then, according to the template shape (or microcomputer preset program), use copying milling machine to process the required shape on the semi-finished plate.

Main process:

Semi-finished plate → trimming → special milling → drilling → edge grinding and chamfering → inspection and packaging.

On the present situation and development of domestic stone processing equipment

. In ancient times, stone processing relied entirely on manual operation. Until the 9th century, the first stone processing equipment appeared in Europe, which brought a revolution to the stone processing industry. From then on, stone processing began to develop from manual operation to equipment. Over the past 20 years of reform and opening up, China's stone industry has achieved rapid development, and the level of stone equipment has also been continuously improved. From the end of 1980s to the end of 1990s to the beginning of this century, the stone industry experienced two climaxes of introducing foreign advanced equipment, which promoted the rapid improvement of the manufacturing level of domestic stone equipment. Of course, if it is compared vertically, it means that compared with its own past, there is no doubt that China's stone industry equipment has developed by leaps and bounds; The horizontal ratio, that is, compared with the developed countries in the international stone industry, the industry will admit that there is a gap. According to the different stone processing methods, this paper makes a simple analysis of the present situation and development trend of domestic stone equipment.

Second, the sawing equipment

There are many kinds of sawing equipment for stone, but at present, frame saw and Jing 'an circular saw are still the main ones.

Frame saw is mainly composed of saw frame, chain bar, column frame, saw blade and other parts. Its working principle is that the saw blade installed on the saw frame moves back and forth with the saw frame under the drive of the connecting rod, and at the same time, it moves down continuously through the lifting transmission mechanism, so as to realize the sawing of stone. The earliest frame saw was called steel grit saw because the tools used were steel bars and sand. Nowadays, the development trend of steel grit saw is automation and large-scale. For example, at present, the large frame in the world can produce 120 plates at a time, and the stroke of the saw blade is 80 cm. In addition, the sawing process parameters of the sawing machine can be automatically adjusted within a certain range, and the connecting rod stroke can be automatically compensated without stopping.

Because the steel grit saw consumes a lot of steel grit and lime, a large amount of steel scrap mortar produced after processing is difficult to treat, causing serious environmental pollution and loud noise. Therefore, a significant development trend of the current frame is to use the saw blade with diamond sintered block as the cutting tip. 1970, Italy first introduced two kinds of large frame sawing machines using diamond bit saw blades. The sawable marble block is 2 meters wide and 3.5 meters long. It can saw 100 pieces of plate with thickness of 2 cm at a time, and the production efficiency is 20% higher than that of ordinary frame saw.

At present, this kind of diamond saw blade is mainly limited to the processing of marble, and cannot be used to cut hard stones such as granite. The reason is that when the saw blade of the frame saw moves back and forth, the diamond abrasive on the diamond sintered block cutter head can not form trailing support, and the clamping force is small, so it is easy to fall off from the matrix. Therefore, frame saws have been used to saw granite slabs.

Because the sawing process of frame saw is discontinuous, the sawing speed is slow, generally less than 2, which seriously restricts the improvement of machining efficiency. Therefore, a new stone processing equipment-diamond circular saw came into being. The sawing machine is mainly composed of a frame, a saw blade driving motor, a diamond circular saw blade, a lifting feed guide device, a saw blade translation guide device and the like. Its working principle is that the diamond circular saw blade installed on the spindle rotates on the beam guide rail and makes linear reciprocating motion, and the saw blade moves up and down through the lifting feed guide device and eats the knife accurately. Compared with frame saw, the cutting speed of circular saw can reach 30~45, which greatly improves the processing efficiency. Therefore, at present, the disc sawing machine is the most widely used sawing equipment in stone sawing. However, on the other hand, the sawing depth of circular saw is limited by the diameter of the saw blade, and generally cannot exceed the diameter of the saw blade. 1980, Germany successfully developed a circular saw blade with a diameter of 5 meters, which is said to be the largest circular saw in the world. However, because the driving shaft of the sawing machine can not completely and effectively support the heavy circular saw blade to cut along the vertical plane of space, and because the diameter of the saw blade is too large and the sawing path is not straight, it is technically difficult to make the circular saw blade very large. Although the tangential speed of circular saw blade is much higher than that of frame saw, it is not as good as that of frame saw in terms of sawing depth and the number of plates sawed at one time. Therefore, in the production of slate, it is impossible for the circular saw to completely replace the frame saw in a short time.

In order to further improve the efficiency of stone processing, people put forward a combined saw on the basis of a single circular saw, that is, multiple circular saws are installed on a main shaft at certain intervals to process stone. Although the combination saw and the single-disc saw have not greatly improved the structure of the saw, the number of saw blades of the combination saw can be as many as hundreds. Therefore, hundreds of wool boards can be produced in one process, which greatly improves the production efficiency. On the other hand, in order to improve the automation of stone processing, people use combination saws to cut stone slabs and horizontal saws to cut stone slabs into slats. This kind of Jigsaw and cross saw are concentrated on one machine, which is a two-way cutting machine. Bi-directional cutting machine is the main engine of production line and the fastest developing equipment in modern stone industry. Using bidirectional cutting machine for machining can greatly improve production efficiency and reduce production cost.

Diamond frames and granite sand saws used in domestic stone industry are mainly imported from Italy. After entering the 20th century, several domestic companies began to digest and absorb the technology of Italian large-scale plate processing equipment, and produced domestic frame materials and granite sand saws. However, due to the lack of mastery of key technologies, there is still a big gap between the two in terms of work efficiency, cost reduction and continuous trouble-free operation. Guangdong Lida, Fujian Sheng Da, Guangdong Keda and Jinan Hengyunda all produce frame materials and sand saws. The granite sand saw produced by Shanghai Feizhou Company has introduced the technology of Italian BM company, which has good quality and performance and has a high market share in China. Marble row saw is widely used in China, and the domestic equipment is relatively mature. The main problem is that there are many faults in the guide rail system and hydraulic tensioning system of the saw frame. Italy's equipment is mainly double-link and domestic equipment is mainly single-link. Shandong Huaxing has designed a hydrostatic guide rail and a diamond frame saw driven by double-link and will put it on the market this year.

Granite sand saw is seldom used in domestic stone industry. Except for a few large enterprises and foreign-funded enterprises, most enterprises have basically stopped production of sand saws. The main reason is the lack of experience in the operation and management of sand saws in China, especially the mortar batching and slurry supply system of sand saws is still far behind that of Italian stone enterprises.

The number of domestic marble frame saw blades is mainly 80 and 400; Granite sand saw includes 120 saw blade and 156 frame saw. The development of sand saw is mainly in the direction of high-speed cutting and ultra-thin saw blade, and the development of sand saw is mainly in the direction of large-scale multi-saw blade. At present, Shandong Huaxing has developed a new type of granite sand saw, which is being tested. After the success of this technology, the cutting efficiency of sand saw will be increased by more than 10 times, which will greatly promote the progress of granite plate cutting technology.

A few domestic enterprises use diamond beaded wire saw to cut large format plates, but there is a big flatness error when cutting large format plates with wire saw. When the thickness requirement is strict, it is necessary to fix the cut plate with a constant thickness machine, and the cutting cost is high.

In addition, when cutting pillar and lath, diamond disc sawing machine and special cutting machine are mainly used for processing. At present, there are many stone cutting machines, stone cutting machines and mushroom stone cutting machines.

Spindle and pressurizing device, upright post, rocker arm seat, lifting motor, screw, handrail, etc.

The working principle of the machine is that the main motor drives the vertically installed spindle and the grinding disc installed below the spindle to rotate, and the grinding disc can move up and down along the surface of stone products in a limited range with the help of two rocker arms, and the grinding stone on the grinding disc can polish the stone surface through a pressurizing device or manual pressurization, thus completing the grinding and polishing operation. It can replace the grinding disc manually on the same machine tool, and complete all the operations of rough grinding, semi-fine grinding, fine grinding, fine grinding and polishing. Its main advantages are simple structure, convenient operation and low investment, but the strength of workers is high and the area of plates that can be processed is limited. Because the replacement of grinding discs with different particle sizes is determined by the naked eye observation of workers, it requires high technical level of workers, and the final product quality will vary from person to person. At present, the equipment is mainly used for grinding and polishing special-shaped plates. Multi-head continuous grinding and polishing machine is a new advanced grinding and polishing equipment. By installing several different grinding blocks and polishing blocks on the production line, the whole processing process of rough grinding, fine grinding, fine grinding and polishing of stone can be completed at one time. This machine is mainly composed of grinding head, grinding head motor, grinding disc transmission frame, frame, automatic conveyor belt and transmission shaft, main control panel, grinding disc control panel, oil pressure station and water spray cooling device. Continuous multi-head grinding and polishing machine has a high degree of automation. Operators have low labor intensity, high production efficiency, good reliability, low production loss, high machining accuracy and stable quality of polished plates. This kind of equipment has been widely used at home and abroad. At the same time, it also has some shortcomings, such as complex installation and debugging, large investment, high production cost, etc., and it can only process plane plates, but not special-shaped plates. At present, the equipment is widely used in the processing of ordinary flat plates, especially the processing of large-area decorative plates.

Domestic continuous grinding and polishing production line has been widely used by domestic stone enterprises in recent years. For example, the continuous grinding and polishing machines produced by Guangdong Keda, Fujian Sheng Da and Guangdong Hesheng are also widely used in the domestic stone processing industry. Shandong Huaxing developed a continuous grinding and polishing production line, which was sold to countries such as Vietnam and Kazakhstan last year. Stone polishing technology is also developing constantly. In recent years, resin abrasives have widely replaced magnesia abrasives, and diamond abrasives have also been widely used.

The main development direction of stone polishing equipment is to adopt new electrical control technology to realize the integration of light, liquid and electricity. At present, the grinding and polishing thickness of large-scale plate grinding and polishing equipment is getting thinner and thinner, and the grinding and polishing technology of wide thin plate will be applied.

The gap between the technical level of domestic stone grinding and polishing equipment and Italy's advanced technology is narrowing. With the continuous improvement of the manufacturing and design level of stone equipment manufacturers, domestic grinding and polishing equipment will surpass Italy.

Four. Special-shaped processing equipment

Due to the high added value of special-shaped stone products, the requirements for special-shaped stone products are increasing day by day, whether in modern architecture or in the manufacture of stele furniture. If the special-shaped processing of stone is processed by hand or single process equipment, the labor is large, the production efficiency is low, the polishing cost is high, and it is difficult to meet the quality requirements; In addition, the use of high-quality steel is a rapid tool wear. Therefore, there are many equipments specially designed for special-shaped stones at home and abroad. Special-shaped stone processing equipment can be divided into two types according to the different processing shapes of products: one is used to process special-shaped stone products with equal cross section, or the other is special-shaped rotary products with known cross section shapes but different areas; The other is used to process three-dimensional products with different cross-sectional shapes, and their control dimensions are different. According to the different processing shapes of special-shaped stone products, the requirements for equipment are different. For special-shaped stone products with equal cross-section or special-shaped rotary products with different cross-section shapes, diamond beaded rope saw and high-pressure water jet technology are mainly used, and for three-dimensional space products with different cross-section shapes, copying numerical control equipment is mainly used.

Numerical control diamond beaded saw is a numerical control processing equipment for processing special-shaped stone products with flexible tools, which is mainly composed of rope pulley, diamond beading, guide wheel motor, frame, rope pulley propulsion equipment and so on. The cutting tool used in this machine is beaded rope, which uses the diamond particles contained in beading (diamond sintered ring) to move at a high speed on the stone surface at a linear speed of 20 or higher. Cutting stone is suitable for processing special-shaped stone products with large volume and thickness. The rope saw has the advantages of high cutting efficiency, large cutting area, flexible use, no noise and vibration, and smooth cutting surface. At present, the beading saw has developed from a single-rope beading saw that can only install one diamond beading rope to a multi-rope diamond beading saw that can install 60 beading ropes at the same time. Compared with the earlier multi-rope beaded saw, the multi-rope beaded saw has become more portable and practical, and the overall size of the equipment is almost the same as that of the ordinary beaded molding machine.

High-pressure water jet technology is a stone processing technology with high-pressure water jet or abrasive jet as cutting means. It enters the field of stone processing with the processing of special-shaped stone products as a breakthrough, and its application in stone processing has developed rapidly. This is a cutting technology with simple cutter, no dust pollution, low noise and narrow incision. In the stone industry, it is mainly used for the processing of stone jigsaw puzzles and various flat stone signs, with large batch and high precision. Numerical control high-pressure water jet cutting machine consists of high-pressure water pump, working host and numerical control system. This technology and equipment are far lower than the processing equipment used in the current production, with low processing cost and energy consumption, and the wear materials and water can be recycled, so the equipment has a wide range of applications. It is a promising new technology in the development of China stone industry. Because the related technology and key problems have not been completely solved, it has not been widely used in domestic stone processing.

Although rope sawing machine and high-pressure water jet cutting machine are widely used in the processing of special-shaped stone, strictly speaking, these two devices can not complete the processing of real three-dimensional stone products. With the development of computer technology, various multi-functional and efficient NC machining equipment have appeared for three-dimensional products with different cross-sectional shapes. These processing equipment can be programmed to complete the processing of various complex shaped stone special-shaped products, such as revolving body, main body carving products processing, plane carving processing and so on. The biggest advantage of this kind of processing equipment is that it can complete multi-process operations with one clamping, and the processing quality and accuracy are very high, which is very suitable for processing complex contours. The disadvantage is that it can only be produced in one piece, and the technical requirements for tools are very high.

At present. There are also dozens of special-shaped stone processing equipment in China, but there is still a big gap compared with advanced equipment such as Italy. In recent years, a few large stone processing enterprises in China have imported CNC special-shaped processing equipment from Italy to process complex special-shaped stones. Imported special-shaped processing equipment mainly includes stone processing center, horizontal CNC machining machine tool, vertical CNC machining machine tool and CNC desktop machining machine tool.

Special-shaped stone processing has many processes, even large enterprises do it by hand, especially the grinding and polishing of irregular surfaces. Although there are many kinds of special-shaped processing equipment in China, there are no really powerful CNC machine tools, mainly simple CNC (two-axis linkage, three-axis linkage) machine tools, and then special-shaped processing is carried out by using forming tools. Special-shaped stone processing equipment has a large development space, and its main direction is multi-dimensional numerical control, grinding and polishing technology of special-shaped stone equipment, and processing equipment and tools of various complex spatial curved surfaces. Special-shaped stone processing equipment can learn from the structure and control technology of metal numerical control processing equipment. The technology of special-shaped processing equipment for stone plane is mature, and the special-shaped processing equipment such as CNC diamond beaded rope saw, CNC water cutting machine tool and 3D CNC milling machine are mature, which are widely used in stone processing. The cutting, grinding and polishing technology of round stone and spherical stone is relatively mature. In recent years, special-shaped edge grinding equipment (especially all kinds of round edges) has been continuously pushed to the market, realizing multi-head continuous grinding and polishing, and the equipment level has been continuously improved.

It should be pointed out that in addition to the above centralized main processing equipment, stone equipment should also include diamond chain saws and chamfering machines. The use of other equipment in stone processing is limited, so I won't go into details here.

3. Stone equipment is developing towards environmental protection, such as the development and application of environmental protection processing equipment such as diamond beaded rope saw and high-pressure water jet.

It can be predicted that with the progress of stone processing technology and equipment, stone processing enterprises will develop in the direction of factory, information management, high quality, low consumption and high efficiency automation, which is still the eternal theme of stone equipment development!