Gill Wilson LV.2 Lurker
May 13, 2022, 06:49 PM 24 read

How does WPC Differ from Shot Blasting?


WPC or Fine Particle Peening is a shot peening method that improves the mechanical properties of metal products. Shot peening is a cold working process used to apply residual compressive stresses to the surface of a component, resulting in a change in mechanical properties.   The advantages of shot peening include increased strength and fatigue resistance even when processing complex geometries.   WPC differs from shot blasting in that the shot blasting medium is much smaller (WPC is also called fine shot peening/ micro dimple process) and harder, and the part is struck at a much higher speed.

凱薩: 生產製造 - How does WPC Differ from Shot Blasting? image 2

Image Credit:   Due to its extremely fine grain, WPC has a higher resistance to fatigue and stress corrosion cracking than shot blasting. The medium used improves the ultrafine material, which, when ejected at high speed towards the product's surface, creates compressive stress at the points of impact.   Solid lubricants such as tin (Sn), molybdenum disulfide (MoS2), or tungsten disulfide (WS2) can be used as a medium in the WPC process to incorporate them into the surface of the product. However, the process is, for the most part, kept secret.   Due to the lightweight of the blasted medium, WPC can also be used on fragile parts such as piston rings and even bearings. These properties make WPC an excellent process for cylinder bores, pistons, rings, piston pins, gears, and anywhere low friction can help.   The surface treatment of WPC metal is unmatched in the treatment of engine parts and other surfaces that have friction points. WPC is not a coating, but it is a surface treatment to reduce friction and strengthen engine parts.   The WPC treatment process bombards the metal surface with a special medium (microscopic ceramic balls) at high speed, leaving micro-pits on the solid surface. The second point is that the WPC treatment creates a nanocrystalline structure on the metal surface.   WPC processing is similar to micro shot blasting, which changes the surface shape, surface hardness, and grease retention (I don't know if that's the right word, but oil sticks better) metal surface properties.   This micro shot blasting treatment produces micro dimples on metal parts that reduce friction and, therefore, increase performance and durability.   Like shot peening, WPC exposes the part to a spherical projectile to create surface compressive stress, plastic deformation, and grain refinement. This is another benefit of WPC, as WPC will reduce friction on parts that are already smooth, like glass.   However, due to the small weight of the bracket, the affected area of ​​WPC treatment is less than 0.001, which is much smaller than that of shot blasting.   So, in a nutshell, WPC is a metal surface treatment process that will increase the fatigue strength and lubricity of parts in an automotive engine, thereby increasing efficiency and prolonging life.  

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