1 Implementation steps of EPC production process
EPC technology is the key and equipment is the guarantee.
(1) Preliminary investigation work
The preliminary investigation work is divided into two aspects: first, to understand the knowledge about EPC from the Internet and professional books; The second is to bring their own products to the same industry or similar products of enterprises to visit, to see their production situation, the redeeming points and deficiencies in the production process.
(2) the trial production
The pilot production process includes a vacuum negative pressure system, a vibrator, several vacuum sand boxes and several tons of sand. White mold to support the main, relying on the relevant professional manufacturers to provide white mold sample or with foam board for cutting and bonding. Smelting can be done with existing cupolas or electric furnaces. Vacuum negative pressure system for the choice of 2BE series of water ring vacuum pump, if the future development of a large scale can also increase 1. The selection of the vibrating table is generally three-dimensional. The size of the table is determined according to the size of the workpiece and the number of the workpiece placed in the sand box. In principle, the size of the vibrating table shall not be less than the size of the vacuum sand box. In addition, if the choice of the vibration platform is the assembly line operation, it is necessary to match the roller or the movable three-dimensional vibration platform, otherwise the three-dimensional vibration platform can be used as a flat plate. In addition to the size of the vacuum sand box, the main consideration is the form of vacuum pumping. The conventional bottom pumping type can also be designed as the bottom pumping type and both sides pumping type to make the vacuum uniformity good, the sand strength is high, the box is not easy to collapse, and the gauze net is easy to be replaced. There is no need to turn over the sand box, it is side leakage type, not easy to damage the gauze net, there is no need to add bottom sand every time after one use, greatly reduce the labor intensity of workers, save working time and improve work efficiency. Baozhu sand should be selected for sand, Baozhu sand has high refractoriness, is not easy to break, high reuse rate, no dust, good air permeability, good filling, no silica dust harm, belongs to the green environmental protection foundry sand.
(3) mass production and economic effect
For their own products, according to the trial production of the development of process, batch expansion of production. Mass production, not blind investment, must pay attention to its economy. It is not comprehensive to combine economy with technology and only look at technology without looking at economy. The service life, technical life and economic life of EPC equipment should be considered together. The design and manufacturing quality of the equipment, the frequency of use, the intensity and the maintenance level of the equipment determine the service life; Technological progress and technological innovation affect technical life. From the perspective of the development of EPC technology in China, the technical life of the equipment is only 3 ~ 5 years, and the economic life and service life of the equipment can reach 6 ~ 8 years, which is longer than the technical life. Therefore, the investment of vanishing mode equipment should be saved and reduced as much as possible, and economic benefits should be put in the first place.
2 Selection of sand treatment equipment
General small and medium-sized enterprises lost mold sand treatment system selection of annual production capacity within 8000T, installed capacity is not more than 50KW, in order to make the equipment investment, cover an area of small, save energy. The production of sand screening machine is a double-layer structure, both screening and cooling, while the vibration motor has a protective effect, because the sand in this level of the highest temperature. In addition, the screen of the sand screen machine is also specially made, long service life, convenient replacement. Pre-cooling the sand at the first stage also relives the pressure on the equipment behind it, and allows for more complete cooling at the end. Second, when the sand through the chain bucket to the preparatory sand to reach the air separation magnetic separator, can be further cooling, dust removal and magnetic separation of sand and iron beans, and then again bucket to reach the sand temperature regulator. The key to the effect of sand treatment system is dust removal and cooling. The cooling methods are generally divided into two kinds: water cooling and air cooling. Water cooling is the use of circulating cooling water, low inlet and high way to let the water flow to take away the heat of sand and cool down; Air cooling takes heat away by blowing the sand with a fan and allowing it to “boil.” Whether water-cooled, air-cooled or both are used alone, the sand must be reduced from about 800℃ after casting out of the box to within 50℃ for re-use. From the principle of comparison, the water cooling power consumption is small, the effect is obvious, the air cooling energy consumption is large, is a “through type”, the cooling is not complete, can only take away the surface temperature of the sand, can not reduce the temperature of the sand. From the point of view of the current domestic sand temperature regulation equipment, the first use is boiling cooling bed, using the dual principle of water cooling and air cooling, but the actual use effect is not satisfactory. The reason is that although the sand is “boiling”, the water and the wind, but through the speed is too fast, can only reduce the temperature of the surface of the sand, can not completely reduce the temperature of the sand. So the operation of the boiling cold rise lengthen, and some even do two – stage boiling bed cooling. The principle is good, the effect can also basically achieve the purpose of cooling, but the disadvantages are obvious: equipment investment is large, covers an area of large, more serious is the huge consumption of energy, a boiling cooling bed power is often reached more than 20 kilowatts, while the noise is also large. Later, a sand temperature regulator was developed to allow circulating cooling water to enter and rise in the seamless steel tube. After the sand temperature was completely reduced to the required temperature, the sand gate was opened to release the sand. Compared with the boiling cooling bed, although the sand temperature regulator only uses the principle of water cooling, the cooling is thorough, the area is small, the energy consumption is low, the only shortage is long cooling time, and discontinuous. The cooling drum developed later is driven by a speed regulating motor to rotate the drum, and the sand is cooled with circulating water. The effect is more ideal, but the drum is longer, occupies a larger area, and also has appropriate energy consumption.
Post time: Jul-06-2021