Can casting shrinkage produced by gravity casting machine be prevented?
Although the use of gravity casting machines to produce castings is used in many industries, and the castings produced are also well received, but the castings still occasionally shrink. The shrinkage scale of the casting products will not match, and the manufacturers will be anxious to avoid this situation. .Such physical natural shortening cannot be prevented, but it can be improved.
The main reason for the shortening of castings is the shortening of casting products caused by uneven wall thickness, heat dissipation, and different solidification conditions during the casting process. Therefore, we can expand the reserved size, change the mold design or casting process, or set up special feeding. The system feeds the shrinkage part. In the casting process, the improved process can delay and evenly shorten the casting.
In the production of gravity casting machines, it is also possible to reduce the pouring temperature during casting, prolong the pouring time and expand the shortened machining allowance to improve the shrinkage of castings. Although there is no way to prevent casting shrinkage, manufacturers should try their best to pass the above There are ways to improve shrinkage, so that the amount of secondary processing of casting products can be reduced, thereby reducing production costs.
If the residence time of the sand core in the casting of the gravity casting machine is too short during production, the casting may not be cooled and formed, and if the sand core is taken out too quickly, it will cause problems in the molding of the casting, deformation of the casting, etc. If during production, the inside of the casting If the sand core stays in the casting for too long, the force caused by the shortening of the casting will increase, which will lead to a greater core pulling force, which will reduce the efficiency of production.
Therefore, when the gravity casting machine is produced, the sand core in the casting should be taken out when the casting is cooled to a certain temperature range and has sufficient casting strength. The appropriate core pulling and casting molding time are generally tested by experiment. method to confirm.
