On the afternoon of April 20, the "Cross-regional Slate Determines the Future" 2021 China Slate Summit, co-organized by China Ceramics Headquarters, China Slate New Material Exhibition and Procurement Base, and Ceramic Industry News Digest, was shared offline in China The multi-energy conference hall on the third floor of the Ceramics Headquarters came to a successful conclusion. Sharing from multiple angles and dimensions, I believe it will bring a lot of thinking and help to friends in the industry. The following is the dry information shared by Zhang Boqing, a professor at Jingdezhen Ceramics University!
Stone slabs have brought a blue ocean to the industry, but how to make slabs well? How to make slate well in the home furnishing industry and the general home furnishing industry? These problems not only bring difficulties to the industry, but also bring challenges to ceramic machine equipment operators. For ceramic machine equipment and even the entire rock slab industry, a very critical question for making rock slabs is: how to process the slabs well? This prevents cutting and cracking during processing.
Slate, as a kind of plate, must be cut and processed to be used in different scenarios. Therefore, how to objectively evaluate the processability of rock slabs is an issue that needs to be solved urgently.
/ How to determine the workability of rock slabs? /
What parameters can be used to characterize the processability of rock slabs? Some people have proposed to determine it through density analysis method and stress distribution, but it is relatively difficult. In the future, there may be newer technologies and equipment that can meet these determination methods. Although it is difficult to determine the processing performance of rock slabs, some people have done some research and development work in the past two years. Professor Wu Jianqing of South China University of Technology used ultrasonic waves to mark the stress distribution of each plate. Professor Wu encountered several situations during the test. One is that the cracks deflect in the direction of small compressive stress. The other is the first knife cracking (cracking from the compressive stress toward the tensile stress area), and the cut will cause a change in the stress state. The actual stress of some plates is different, but during the cutting process, no cracking occurs, or the cracks do not follow the direction.
At present, it is temporarily impossible to evaluate the processing performance of rock slabs theoretically. So how do companies do it in reality? I have visited several companies and basically use trial cutting methods to verify the processability of rock slabs. For example, the board is divided into many grids, cut into many pieces, and tested in the workshop to prove that it will not crack.
Some companies use curve cutting, which means that the stress situation can be seen through curve cutting. I have also discussed this method with many people. Assuming that it does not crack when cut with one knife, in principle, the possibility of cracks in this kind of board is relatively small. Because under normal circumstances, if the first cut is made, it will crack, and it will crack; if it does not crack, it will not crack later.
/ Causes of cutting cracks /
The second question I want to briefly talk about is what causes rock slab cutting cracks? How to hack it? I believe that the root cause of cutting cracks in rock slabs is the release of residual stress within the material. If the residual stress is not completely released, cracks will inevitably occur during the cutting process of the rock slab. This is the fundamental reason.
Materials will inevitably generate stress during processing, so how to solve the residual stress? I think there are two aspects. First, during the production and manufacturing process, we must strictly control the formula, glaze, firing and the entire process to produce rock slabs that meet the requirements; formulate a scientific formula structure and start from the microstructure of the product to improve It improves the crystal structure of the green body and improves the fracture toughness of the product. Tailor-made rock slab firing process. During the firing process, the firing curve is scientifically adjusted to reduce the impact of thermal stress on the product, improve toughness and workability, and make the rock slab less likely to crack.
Second, the processing process must be controlled. If the board is very good, but the processing equipment is not well controlled, such as the sharpness of the blade, rotation speed, etc., cutting cracks or even chipping will occur, and the board will be useless. Therefore, the correct use of tools is important. When cutting boards, you must use a special rock board cutting saw blade, and always keep the saw blade sharp. Otherwise, the surface of the cut rock board products will chip, showing jagged edges, severe bottom collapse, and possible corner breakage, seriously affecting the product. quality, and may even lead to product scrapping.
Pay attention to the details. After all, rock slabs are different from other materials. We found that the processing of rock slabs is much more difficult than the processing of glass, and there is a common problem of cutting cracks in various enterprises. I have been to many companies, and some companies that were early in the industry in making slates should have figured out a set of technical parameters for slate production that are suitable for them, so that the products they produce can be processed and cut at will. Some companies even have slate finished product processing with a damage rate of 30%-40% in the early stage, and now the processing integrity rate can basically reach 99%.
/ Things to note when processing rock slabs /
The third question is about what should be paid attention to when processing rock slabs. The processing of rock slabs mainly includes cutting, drilling and edging.
Slabs below 6 mm generally use a glass tile cutting machine, which is manually broken and then edged, which is more convenient and fast. For rock slabs thicker than 6 mm, bridge cutting and waterjet are generally used. The waterjet cutting process has high stability, and the cut rock slabs are smooth. It can increase the smoothness of the rock slabs when cutting straight lines or curves, and can complete the cutting of any complex shapes and patterns.
Feed speed, operating pressure, work force during cuttingImproper rotational speed of the tool, uneven cutting table, movement or vibration of the rock plate during the cutting process, improper cutting tools, etc. will all cause the rock plate to break during the cutting process.
/ Main equipment for rock slab processing /
The fourth question is to introduce the main equipment currently used for processing. The first is the bridge cutting machine. The bridge cutting machine now has double heads and double knives. The first knife and the second knife are made of different materials. The first knife is a resin blade with slotting, and the second knife is alloy steel. Blade, cutting. A knife is used to groove and then cut, so that the problem of cutting cracks is less likely to occur during the processing.
Aitao 3200x1600 rock plate double-head CNC bridge cutting machine
Then there is the water jet. Now the water jet can cut into various special-shaped rock slab parts. The fully automatic CNC cutter head can achieve precise cutting, fast speed, linked cutting in any direction, etc. The rock slab, especially the panel, needs to be made beautiful. Without the equipment of water jet, it is definitely not possible.
/ Development trend of deep processing of rock slabs /
Finally, let’s briefly share the development trend of deep processing of rock slabs. Personally, I feel like we need to do three things.
First, manufacturers should set up stone slab processing centers (enterprises and regions). The upgrading of processing technology and the establishment of automated rock slab processing centers are important processes for converting rock slabs into products. Because slate is not just selling boards, but also selling finished products. Last time I had a student from Hangzhou ask me if it would be okay to use slate for home decoration. I said yes, and he asked what should I do if I drill a hole? I said that when you buy, tell the other party the size and requirements, and ask the other party to prepare the finished product or semi-finished product before sending it over. If you buy a rock slab and take it home directly, you won’t be able to use it yourself. In the future, the goal of rock slab manufacturers is to sell finished products instead of selling a single slab, and solve all cutting and cracking problems within the factory. If there are one or two cutting cracks in the factory, it doesn't matter. The deep processing problem must be eliminated in the factory. What the company sells is not boards, but components, including the final kitchen and bathroom countertops and cabinet panels.
2. Rock slab companies cannot just sell rock slabs, but must build a whole industry service chain. This is the key to the success of rock slab supporting services in the future. In order to complete personalized customization and improve the quality of consumer demand, it is necessary to improve basic processing and supporting services and create a full-line service chain. Establish a platform for logistics distribution, design application, and cross-border innovation integration. By establishing regional storage warehouses, we can achieve efficient regional operation, efficient distribution and delivery, and truly achieve the platform benefits of "short, frequent, and fast".
3. The deep processing of rock slabs will develop in the direction of flexibility, dataization and intelligence. The client's demand data is directly input into the processing equipment, and the processed products are delivered to the customer through logistics to achieve interconnection and reduce intermediate links. If a complete service chain like this is opened up, I believe that China's rock slabs will be a blue ocean in the future.
