The sand core produced by the sand shooting method of the core shooter is of good quality, and the process is easy to realize automation. Therefore, the core making process of the core shooter has been applied for a long time. It has the advantages of short production cycle, good quality, low cost, low noise, etc., and is increasingly widely used.
On a small sand shooter, starting from the shooting time, compressed air enters the sand shooting cylinder and fills the core box, requiring only 0.3-o 5s。 Before and after the small pressure of the sand shooting cylinder reaches the high point, the shot has been basically completed and the core box has been filled. The working principle of core shooter is that compressed air expands suddenly to inject core sand into the core box.
The production efficiency of the core shooter is high. The working process of the hot core box core shooter is completed at the same time of sand filling and compaction, and it is hardened in the hot core box immediately. A cycle cycle only takes ten to dozens of seconds to produce sand cores for casting. Core shooter has good sand core quality: it can shoot sand cores of any complexity, and its size and surface are smooth, thus reducing the machining allowance of castings.
The sand shooting process of the core shooter can be roughly divided into three stages. The stage is the early stage of shooting. After the quick air inlet valve is opened, the air pressure in the sand shooting cylinder rises at the initial stage, and the molding sand cannot be shot out. The molding sand can only be shot out from the perforation when the air pressure increases to a large extent.
Followed by free shot sand, sand particles are driven by air flow and shot out of the core box by perforation. The third stage is the compaction of the sand control group. After the core box is almost full, the free sand shooting stage is formed. However, the movement of the core sand into the core box has not stopped. Driven by the difference between the air pressure in the sand shooting head and the air pressure at the upper part of the core box, the core sand continues to fill the core box. In the perforating process, it was originally a sparse gas sand flow, which became a dense flow of the sand groups pushing each other. This part of molding sand pushed in later is called sand pressing group, which can further improve the compactness of molding sand on the upper part of the core box.
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