Sandblasting process

Selection of sandblasting equipment 1 Generally speaking, the sandblasting effect is mainly determined by the part material and sandblasting abrasive According to the different materials of parts, the abrasive range of sand blasting can be from metal abrasive with strong effect to resin abrasive with soft effect At the same time, dry sand blasting and liquid sand blasting are also the key factors to be considered 2 Determine the type of equipment for production efficiency: select automatic sand blasting production line, semi-automatic sand blasting equipment, press in sand blasting machine and suction sand blasting machine according to the processing capacity 3 Determine the equipment specification according to the workpiece size: select the engine room size according to the workpiece size, so as to have enough space to complete the processing work 4 Compressed air requirements: determine the capacity of air compressor according to the equipment specifications, and leave 20% margin to protect the service life of air compressor 1 Function or purpose 1 Cleaning of workpiece surface It can be used to treat the rust layer of metal, residual salt and oxide layer on the surface of heat-treated parts, oxide layer on the surface of rolled parts, oxide layer on the surface of forged parts, oxide layer on the surface of welded parts, sand and oxide layer on the surface of casting, residual dirt and tiny burr on the surface of machined parts, and the surface of used parts, etc., so as to remove the surface adhesion layer and reveal the true color of the substrate The surface cleaning quality can reach grade SA3 2 The pretreatment before coating can be used as the pretreatment of various electroplating, brush plating, spraying and bonding processes to obtain the active surface and improve the adhesion between coating, coating and bonding parts 3 Changing the physical and mechanical properties of the workpiece can change the surface stress state of the workpiece, improve the lubrication conditions of the mating parts, and reduce the noise during the movement of the mating parts It can harden the workpiece surface, improve the wear resistance and fatigue strength of the parts 4 The surface roughness Ra of the workpiece can be changed by the polishing of the workpiece surface Can produce matte or diffuse reflection of the workpiece surface, in order to achieve the purpose of finishing 2 The main parameters that affect the sandblasting process: abrasive type, abrasive particle size, abrasive concentration, spraying distance, spraying angle, spraying time, compressed air pressure, etc 3 Environmental protection characteristics 1 Greatly improved the pollution of dust to the environment and the harm to workers' health 2 It can be directly installed on the production line, saving production area and favorable for workpiece turnover 3 The working method is flexible and the process parameters are variable, which can meet the requirements of different materials and different precision parts 4 During the working process, the abrasives are recycled, with consumption of  5 The main parts have a long service life and are easy to maintain Three factors of surface results obtained by common sand blasting process parameters: acceleration of compressed air on jet flow (adjustment of sand blasting pressure) P type of abrasive (s) distance of spray gun (H), angle (θ) 1 The influence of pressure adjustment on surface results is in s, H The higher P value is, the higher the speed of jet flow is, the higher the efficiency of sand blasting is, and the rougher the surface of workpiece is On the contrary, the surface is relatively smooth 2 The influence of the distance and angle of the spray gun on the surface result is the key of the manual sandblasting technology after the P and s values are set The distance between the spray gun and the workpiece is generally 50-150 mm The farther the spray gun is from the workpiece, the lower the efficiency of the jet flow and the smoother the workpiece surface The smaller the angle between the spray gun and the workpiece, the lower the efficiency of the jet flow and the smoother the workpiece surface 3 The influence of abrasive type on the surface result abrasive can be divided into two types: spherical abrasive and diamond abrasive Diamond abrasive is commonly used in sandblasting Glass beads are spherical abrasives After the three values of P, h and θ are set, the surface result obtained by spherical abrasive blasting is relatively smooth, while the surface obtained by diamond abrasive is relatively rough, and the same abrasive is divided into coarse and fine In China, the coarseness of abrasive is divided according to the number of screens, generally known as the number The higher the number is, the smaller the particle size is The higher the sand blasting number of the same abrasive is, the smoother the surface result will be A