How to choose the particle size of sandblasting abrasives

       The choice of abrasive grain size for blasting mainly depends on the required surface roughness, but also on factors such as the hardness of the abrasive, the thickness of the coating, and the air pressure used for blasting. The particle size range of the sandblasting abrasive actually used is usually divided into three grades; coarse sand (0.6mm~2.0mm, -1 mesh~+30 mesh), medium and coarse sand (0.425mm~1.4mm, -14 mesh~ +40 mesh), fine sand (0.18mm~0.6mm, -30 mesh ~ + 80 mesh). When the thickness of the spray coating is required to exceed 0.25mm, coarse sand is recommended to improve the surface roughness of the substrate and obtain the best bonding performance; when the thickness of the coating is less than 0.25mm and the surface of the substrate is required to be relatively uniform, it is appropriate The use of medium-coarse sand can achieve satisfactory bond strength; when the coating thickness is less than 0.25mm, and the coating is used in the sprayed state (without post-processing), that is, when the surface of the sprayed coating is required to be relatively uniform and smooth, Fine sand blasting should be used. When fine sand blasting, the number of abrasives impacting the surface of the substrate per unit time and unit area and the contact area are large, so the blasting efficiency is high, but the surface roughness is small; on the contrary, the abrasive particle size is large, the blasting efficiency is low, and the surface roughness increases. big.



    For various metal substrates, the recommended grit size is 0.25mm~1.18mm (-16 mesh~+60 mesh); for most plastic substrates, 0.15mm~0.25mm (-60 mesh~+100 mesh) is recommended. Abrasives; for thin coatings, especially thin substrates, fine-grained abrasives should be used with a particle size range of 0.125mm~0.71mm (-25 mesh~+120 mesh); for thick coatings with a thickness greater than 0.25mm, or in order to obtain For the best bond strength, a coarser abrasive should be used with a particle size range of 0.71mm to 1.00mm (-25 mesh to +18 mesh) to produce a rougher surface.