It is a necessary procedure to polish after prototype machined by cnc. When the prototype is being machined, there will be some burrs and tool marks. The surface is not smooth. So it requires handcraftsmen to polish the parts with sand paper.
There are 3 methods to polish the parts, which is mechanical polishing, wet grinding and dry grinding.
Mechanical grinding: When the parts are big, in order to improve the working efficiency, we will use mechanical grinding method such as electric grinding machine or disc type and vibrating grinding machine.
Dry grinding is to use sand paper to polish. It is suitable for hard and brittle lacquer. But its disadvantage is that the operation will produce a lot of dust which will cause air pollution.
(3) Wet grinding: water sandpaper dipped in water or suds burnish.Water can reduce the grinding crack, and improve the smoothness of coating. But after water polishing, we should pay attention to the lower layer of paint, one point is to paint after the parts completely dry, or else it will become blushing. Another point is that water polishing can not apply to material with strong water absorption.
Main purposes of polishing is :
1. Deburr and polish the parts
2.Increase the surface smoothness
3.Make the painting on the parts more adhesive