The current problems in the transformation of ingot casting equipment are the same as in other industries in the photovoltaic industry: low-cost fights. The industry lacks access thresholds, and some customers have short-sighted views. In order to reduce procurement costs, they only seek low prices. Customers, ignoring their safety, reform their own profits and cause some recent security incidents. For the healthy development of the industry and the customer's personal safety, some safety protection measures for the ingot transformation process are discussed here.
The following are the main points that lead to security risks:
First, auxiliary materials (mainly here to talk about)
One of the most important factors for the safety of ingot furnaces is the quality of the crucible, and the occurrence of safety hazards is the root cause of the ingot ingot. This requires:
1. G6 manufacturers should not randomly innovate equipment, and should be cautious before entering into the market without security protection and mature technology. Do not use concepts or functional flaws because of vicious competition in the industry;
2. The manufacturer shall strictly control the process control, inspection and control of the factory's quality.
3, wafer factory quality inspection department to the factory inspection and ingot casting department before use, all equipment should be a detailed inspection, put an end to go through the field;
4, the silicon factory procurement department should not blindly bargain, should pay more attention to quality and select the industry's mainstream manufacturers of products; Similarly, the sales company can not be in order to win the market and suddenly product quality, otherwise it will only outweigh the gains. "Good and cheap" may only be an ideal situation. Purchasing personnel should seek cost-effective products. While cost control is in place, safety production is also checked at the initial level.
Second, the production process control (the following mainly describes the enamel spray, helium silicon material loading and ingot casting process)
1. Slightly different from helium spraying G6 spraying and G5. At present, some manufacturers in the industry use domestically-made powders in order to reduce costs, and minimize the amount of powder, but the final spraying results are not satisfactory. Before the company will use Japan's Ube or Germany's Steck, and other imported powder, but now manufacturers are mostly used to replace the domestic powder, there is no strict amount of the specific dosage standards, most manufacturers use the weight between 600-650g, there are some manufacturers to use 700-800g of powder, but in fact should be based on the actual situation of each manufacturer to determine the amount of powder, such as: silicon material ratio, ingot process, concrete properties, which requires a groping process. The author believes that more reliable imported powder should be used, and the mixing amount should be controlled at about 750g, especially in the vicinity of the four corners and the waste layer. If the bottom is treated, the treatment effect must be paid attention to. The crude quartz sand The occurrence of sticking is more likely than fine quartz sand, and the bottom side of silicon powder must be carefully handled to prevent damage to the spray coating.
2. The bottom of the crucible and the surrounding silicon material should be filled with some flat silicon blocks or side materials to protect the bottom. The four corners should leave gaps. The bottom should be filled with fine materials before the bottom is filled. Due to different sources and different processes, manufacturers can continue to explore and summarize the actual operation process, and pay attention to handling gently when loading. I have visited several manufacturers and found that many manufacturers have problems in this regard, G6 loading large quantities do not respond to success, but can not be ordered by the executive order to set the number of furnaces per day. Large-scale wafer factories are more professional in process control;
3. In the process of material transfer, attention should be paid to the use of a good transfer trolley. The weight of silicon material is more than 1 ton. The loading process is also the same. The personnel at the production line are more aware of this aspect, and the author will not go into details.
4, according to the actual situation of the ingot process optimization: shorten the running time, especially the time of melting the high temperature segment, as far as possible to slow the extent of cooling. If full-fusion efficient technology matures, I still advocate the use of total melting (personal view of the insulation cage half-melting process overflow risk is greater than the total melting process), therefore, in order to reduce the risk, should be a professional process commissioning engineer to operate;
Third, the professional transformation of the ingot furnace (the following discussion of the ingot furnace thermal field design, professional installation and safety device multiple effectiveness)
1. The design of G6 thermal field (thermal field and insulation cage) is a gradual process. Actually, some manufacturers are still adopting the first-generation design, but some manufacturers have already conducted several updates and developed third-generation heat. Field. At present, the dimensions of the main equipments in the domestic mainstream are mostly 1830-1850mm (except for Beijing Yuntong), and the size of the insulation cage is also different. On the one hand, it is required that the cages can be placed in the sill and the guard plate and must not come into contact with the heater. On the other hand, it is required that the four corners of the insulating cage leave as much space as possible for the furnace wall. This requires the design engineer to make a reasonable plan for the size (to exclude the wrong installation of overflowing cotton, personally think that this is the most dangerous area of ​​the accident);
2. The thermal field of the polycrystalline ingot furnace needs to be installed and debugged by a professional equipment installation engineer. Due to the relatively small size of the furnace cavity, if the deviation of the insulation cage on the furnace cavity may cause a safety accident, the installation of the lower furnace cavity is more important. The most important, such as the thickness of the overflow surface, the accuracy of the opening of the overflow cotton and laying, laying of the overflow wire, the setting of the diversion space, and the protective sleeve of the graphite support column. In particular, it is necessary to pay attention to the safety protection at the four corners. Recently, it has also been found that the remanufacturers have installed graphite blocks to prevent overflow in the four corners of the insulation board in the insulation cage. This is to hope that the overflow will trap silicon liquid. . All in all, the details determine the success or failure, manufacturers in the installation of debugging polycrystalline ingot furnace hot field should be walking thin ice, so that stability and stability, try to find professional technical staff;
3. In terms of the safety setting of the polycrystalline ingot furnace, in addition to the above-mentioned design and bottom installation protection measures, there are pressure relief valve inspections and school temperature baking prior to ingot furnace operation. Do not underestimate these details. The key moments are often related to the safety of personnel and equipment. The pressure relief valve design itself is an important safety protection measure for the ingot furnace. This is a summary of previous experience on safety issues. Whether the valve is installed correctly is directly related to whether the pressure can be relieved after an accident. Secondly, the school temperature process does not seem to be important, but the actual furnace temperature monitoring is the only means for our internal monitoring of the cavity, and can guarantee the stability of the ingot process, but many retrofit manufacturers often overlook this step. As regards baking, I will not explain it any more. It is well-known that this is a necessary measure before formal production. Through baking, the overall performance of the oven can be checked.
The author believes that the security of G5's upgrades and transformations is controllable and the technology is feasible. Everyone still needs to look at this new thing with a strange eye. The above experience will hopefully help everyone. Due to the limited level of personal skills, I also forgive me for the inadequacies and hope that more people will discuss this. Live in the moment, and do and cherish! (Neutral: Xiong Yongping)
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