What is the difference between sand blasting and shot blasting?

Sand blasting and shot blasting are two common-used surface treatment methods to machining parts and die casting parts, or pre-treatment before other surface finish after CNC Machining and Casting. But what is the difference between sand blasting and shot blasting?

Shot blasting is using metal projectile, take advantage of compressed air or mechanical centrifugal force as the driving force and friction to remove metal corrosion. The projectile diameter used is between 0.2-2.5mm, compressed air pressure is between 0.2-0.6Mpa. The angle between the jet and the surface is between 30 degrees -90 degrees. The nozzle is made of T7 or T8 tool steel and hardened to a hardness of 50-55 HRC, each nozzle can be used for a period of 15-20 days. Shot blasting is used to remove the oxide skin, rust, sand and old paint film on the medium-sized, large size metal products and castings parts which the thickness is no less than 2mm or does not require the accurate size and contour. It is widely used in large shipyards, heavy machinery plants, automobile plants and so on. The clear effect is obvious with shot blasting. But it is easy to deform the sheet workpiece with shot blasting, and to the part with oil, shot blasting can not clear the oil completely.

Sand blasting is also a mechanical cleaning method, but the sand blasting is not shot blasting. The material used in sand blasting is sand such as quartz sand, but what shot blasting used is metal projectile. In the existing workpiece surface treatment methods, the best cleaning method is sand blasting. Sand blasting is suitable for the workpiece which requires a higher clean-up surface. A lot of dust can be generated during the sand blasting process, it not only pollutes the environment seriously, but also easy to cause the occupational diseases (silicosis). The sand blasting had been instead of by shot blasting widely.

For the difference of the surfaces after shot blasting and sand blasting treatment, it will be clear with the picture below:

Shank Precision Machining Parts Co., Ltd as a china CNC machining parts supplier and manufacturer, we can provide Machining Parts with sand blasting and shot blasting or other surface finish ways as customers’ requirements.