3, can not afford to shell layer, good thermal stability, good thermal conductivity, good liquidity, casting surface; a vibration sand, high-strength, low gas, low expansion; 2, lax, good casting surface finish smooth; 4, high strength, high temperature, low inflation, good mold release, anti-sticky sand is good; 5, the shell is not uniform shelling, fast curing; quality coated sand core in addition to the geometry of the sand core , dimensional accuracy, surface quality and shell thickness outside coated sand regeneration, but also by observing the color of the sand core to test the core sand curing conditions. The normal situation is that the appearance of the sand core should be uniformly brown, center yellow, when burnt brown and even black exterior rendering, insufficient hardening look yellow, white center with Sand cast iron main process parameters: Iron type wall thickness 25mm, covered sand thickness 5-8mm (for small bore ductile iron crankshaft); iron-type quality in general is about five times the mass of castings; iron ore ratio (casting quality and the consumption ratio of the amount of coated sand) 6-7. Iron-type cladding sand molding methods (ie sand overlying obtained) has shot two kinds of sand molding and compression molding coated sand regeneration companies, the former is currently used more, for ordinary coated sand coated sand coated sand regeneration Shandong particularly suitable for mass production; the latter applies to single-mass (iron type size up to several meters in length) of the crankshaft, covering a variety of fluidized sand Sand. The former sand shot selection pressures related to the thickness of the coated sand coated sand regeneration manufacturers, when shooting sand pressure 0.2-0.6MPa, coated sand thickness is 4-5mm, maximum density of ordinary coated sand: its composition is usually quartz sand novolac resin, and calcium stearate methenamine constituted, without the relevant additive. The resin is usually relatively high amount at a certain strength requirements, do not have high temperature, low inflation, low gas and other characteristics suitable for some less demanding, simpler structure of cast iron production. High strength, low gas coated sand: is based on ordinary coated sand by adding the relevant characteristics of "additive" and the adoption of a new preparation process, so that the amount of resin dropped significantly reduce gas evolution, and can delay send gas speed. The coated sand with high strength, low inflation, low gas, gas and other characteristics of slow hair, especially for iron castings, steel castings in small and medium volume requirements for low-fat sand core, such as the body, such as sand cores coated sand regeneration The company _ Qingdao Heng (certified) _ coated sand regeneration provided by Heng Machinery Co., Ltd. Qingdao. Qingdao Heng Machinery Co., Ltd. (www.thjidian.com) is Qingdao, cleaning, cleaning equipment leader, over the years, the company is implementing the scientific management, innovation and development, the principle of honesty and trustworthiness, and satisfy customer needs. Qingdao Heng led the staff warmly welcome all inquiries negotiations to create a better future Qingdao Heng.