drill ro

It is important to know that the shape of the sand has an important impact on the surface finish of the casting. Circular sand is better than triangular sand because the triangular sand has a large gap, which is easy to lead to defects such as porosity; According to the nature of the casting, the sodium silicate quartz sand is selected to form a spalling layer, and combined with the characteristics of cooling and shrinkage of the casting, the surface defects are reduced. Coating a protective layer on the surface of large castings, such as the film on a coated sand mold, can improve the surface finish of the sand mold and reduce the surface defects of the casting.  

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3. Open-air drilling rig: according to the different working mechanism of crushing ore and rock, it is divided into steel rope percussion drill, drilling rig, cone drill and rotary drill. Because of low efficiency, the steel rope percussion drill has been gradually replaced by other drilling RIGS. The drill pipe drives the pneumatic impactor and the drill bit to rotate together, and the piston of the pneumatic impactor is used to impact the drill bit to break the ore and rock, which is usually used in small and medium-sized mines to drill holes with a diameter of 80 to 250 mm.

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