First, the low pressure casting machine is constantly improving
The control method of the low-pressure casting machine is to integrate many advanced control systems, including PC electrical control, microcomputer control, thyristor control and high-flow cartridge valve integration. In the structure design of the whole low-pressure casting machine, J452 is the base, which can continuously improve and improve the position where the fault is more likely to occur. For example, when the horizontal cylinder of the core-pulling mechanism is unsafe, the force is unreasonable. However, the horizontal cylinder is only fixed by the screws for its base, so there is no part that can be supported by the whole cylinder. At the same time, when the side mold is opened or closed, the force of the cylinder will be between 65 kN and 120 kN, which will cause the reaction force of the push-pull to often crack the bottom seat of the cylinder. At the same time, the rigidity of the cylinder is also very poor, which has affected the accuracy of the side mold and the stability of the side mold. In order to prevent the moving template from working under high temperature, there are 8 kinds of protective measures for expansion deformation due to overheating, and there are 3 screw holes and 2 taper pin holes on each of them, so that the mounting configuration is In the process, it can be effectively combined with the moving template. Because the precision of the design of the pressure plate and the guide sleeve is very high, the installation position must be accurate and reasonable, so drilling and tapping are very difficult, which causes this problem to be a big problem in the installation configuration, often There was a situation of repair. However, in the actual use process, it is detected by various indicators. Since the cooling of the mold is a dual-medium six-channel cooling mode, the installation of this configuration does not play any role. In view of the above problems, the structure in the design will be improved to simplify and enhance the reliability at work as the ultimate goal, so that the influence of the hydraulic system on the moving template work can be effectively solved, and some processing is performed on the combined mechanism. Therefore, in a good product equipment design requires strong technical support, there is no high-level design structure without high-level scientific research and development. With the advancement of our society and the development of technology, design needs have gradually entered the category of human high-tech creative activities. It solves the problems encountered when working according to the specific conditions and process rules used.
Second, the configuration of the low-pressure casting machine
Low pressure casting machine
1. Generally speaking, low-pressure casting machines are composed of main components, mold cooling system, electrical control system, hydraulic system, holding furnace and liquid surface pressing device.
2. The main structure of the low pressure casting machine is as follows:
1 Main unit: It is generally composed of a combination mechanism, a safety limit mechanism, a pick-up mechanism, a static mold core pulling mechanism, a casting ejection mechanism and a frame part.
2 Liquid level press: It is mainly to provide correct control. The filling and casting of the mold is the key to producing high quality castings. Its control is completely realized by the liquid pressure control system. It is completely possible to carry out the production according to different casting requirements, and adjust the numerical parameters of the process in the liquid surface pressing system. At the same time, its working requirements are stable and reliable, and the maintenance is simple and quick.
3 Holding furnace: There are two kinds of holding furnaces in general casting, the first one is squat type and the other is molten pool type. However, the 坩埚 type is divided into two types: graphite and cast iron. The molten pool type adopts the overall knotting process of the furnace refractory material, which can make the silicon carbon radiant heating for heat preservation, has the characteristics of large capacity, long service life, convenient maintenance and the like, and is in line with the requirements of continuous production, and is also today Modern low pressure casting machines are widely used. The connection between the holding furnace and the main machine is fixed and the holding furnace is moved and moved. This can be added according to the production process.
Third, the low pressure casting machine process
1. In the low-pressure casting machine process specifications, the coatings in the cavity, the coating life and quality of the coating, the pressurized liquid, the burning temperature, the pressure-preserving crystallization, the mold preheating and the pressure relief cooling are included.
2. In the pressure and speed of the liquid lift, the pressure of the lift liquid refers to the additional pressure required when the metal liquid surface is raised to the gate. The rate at which the metal liquid rises in the pipe of the liquid rise is the speed of the liquid rise. The process of the liquid rise should be smooth, which is beneficial to the elimination of excess gas in the cavity, and also allows the metal liquid to not spray when entering the gate. splash.
3. Filling pressure and speed, the filling pressure is the additional pressure required for the metal liquid to rise to the head of the mold. And in the filling stage, the rate of increase in the surface of the metal liquid is the filling speed.
4. Increase and increase speed means that the metal liquid is continuously pressurized after the cavity is filled, so that the crystal solidification of the casting is carried out under the set pressure. The pressure at this time is called crystallization pressure or can be said to be pressure-holding. pressure. The greater the pressure at the time of crystallization, the better the effect of the shrinkage, so that the final appearance of the casting is tighter and firmer. However, increasing the quality of the casting by increasing the pressure of the crystallization is not in any case.
5. The holding time means that after the cavity pressure of the casting machine reaches the crystallization pressure, and can be maintained for a while until the final casting can be completely solidified, the time required for this part is called the dwell time. If the time is not enough during the process of holding pressure, the casting will not be completely solidified and the pressure will be relieved. Then the metal liquid in the cavity will flow back completely or partially. Choose to continue using or emptying. If the process time of the pressure keeping is too long, the excess of the gate will be too long, which will reduce the process efficiency, and will cause the gate to freeze, which will affect the work efficiency and make the casting more difficult. In production, it is necessary to choose a suitable holding time.
6. The pressure relief stage is to allow the casting to be completely solidified after the end of the solidification, or the part of the gate has been solidified, and the pressure on the internal liquid surface can be removed. There is also a metal liquid that has not solidified in the mouth and returns to the sputum by gravity.
7. When using a metal-type low-pressure casting machine for coatings, it is necessary to brush the paint in order to improve its service life and the quality produced during casting. It should be evenly distributed when painting the coating. The thickness of the coating is determined by the smoothness of the surface of the casting and the overall structural construction of the casting.