Introduction and Application Analysis of Core Shooting Machine and Shell Core Machine

Bestech sand-shot molding currently mainly includes two processes: hot coated sand molding (commonly known as hot core box) and cold resin sand molding (commonly known as cold core box). The two processes are mainly different from the selected molding sand and the corresponding curing methods. For the molding equipment, there is not much difference in the working principle and structure. That is, the molding sand is injected into the core box cavity under high pressure by a core shooting machine (or a shell core machine), and after curing, the mold is opened to obtain a sand mold (or sand core) of solid sand. Molding (core) by this process has a wide range of obvious advantages over traditional clay sand molding:

The surface finish of the casting is high, which can reach ral2.5-25, and the size is accurate (CT7-9), reducing the processing amount and shortening the processing time;

Molding sand has higher fluidity, and it has very good filling ability through air pressure injection into the cavity, which is suitable for producing castings with complex shapes;

Sand mold has high strength, low gas generation, low expansion and shrinkage rate, slow strength decline, long usable time, and good storage stability;

After pouring and cooling, the dispersion is good, and the sand is cleaned by vibration; the shell type can not be layered, and the thermal stability is good.

Compared with clay sand, the production efficiency is more than doubled, and the production environment of workers in the foundry is greatly improved, especially in the production of multi-variety and small-batch castings.

The labor intensity and operator selection requirements are reduced, and most of the core shooter (shell core) machine operators employ female workers, who can be competent for 1-2 workstation modeling work after simple training.

In recent years, due to the rapid development of my country''s high-tech manufacturing technology, especially the promotion of the export growth of machinery, automobile industry and mechanical products, more and more castings have put forward higher requirements on the strength, wall thickness, dimensional accuracy and surface quality of sand molds. When ordering, it is specified to use the core shooting (shell core) process to produce castings. The traditional clay sand molding and oil sand core making can no longer meet the production requirements of high standard castings. The resin sand-shot molding process has developed rapidly, and is widely used in the production of various complex castings such as automobile cylinder blocks, cylinder heads, intake manifolds, various pipe fittings, pump bodies, etc. The core and gearbox core have been changed from furan resin sand to coated sand shell core, which is of high quality and good storage, and is used by the internal combustion engine industry. It can be seen that the resin sand-shot molding process and equipment peak application period

Here is a detailed comparison of the advantages and differences of the two processes, the warm box and the cold box, for users'' reference selection;

Cost of use: The coated sand used in the hot core box process refers to the finished sand with a layer of resin film on the surface of the sand particles before molding. The resin on the surface of the molding sand in the core box is melted and then fused to achieve the effect of overall curing. In the cold core box process, users can use a sand mixer to mix resin sand by themselves, and use triethylamine gas as a catalyst to blow into the core box to solidify the molding sand. Therefore, the purchase cost of molding sand in the cold box process is low, and the gas used as a catalyst is more economical than electric heating. In contrast, the cold box process has obvious advantages in terms of use cost.

Investment cost: It is inevitable to purchase a special resin sand mixer and a triethylamine gas generator for the cold core box when using the cold core box process, which will increase the investment cost of equipment by more than 50% at one time.

Molding quality: The strength of the sand mold (or sand core) made by the cold box process is lower than that of the hot box process, and the usable storage time is shorter than that of the cold box process, but the above two properties are still much higher than those of traditional clay sand molds, core. Usually the difference is not noticeable in use.

Use efficiency: The curing time of the cold box process is much higher than the heating curing of the warm box, which can greatly shorten the modeling time and improve the production efficiency.

Scope of application: The coated sand used in the hot core box is in the form of dry sand. Compared with the mixed resin sand, it has better fluidity and has a better filling type when injected into the core box cavity, so it is easier to manufacture. Sand molds with complex shapes, while cold boxes require higher mold processing technology.