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C.A.S.E. & Vibratory Superfinishing​

C.A.S.E. (chemically assisted surface enhancement) is a two-stage process consisting of shot peening followed by vibratory superfinishing. The fatigue enhancement properties of shot peening are complimented with a mirror like surface finish.


Applications that require both residual compressive stress and excellent surface finish include precision gears and airfoil blade geometry. Depending on the application and customer finish requirements the valleys of peening dimples can be retained for lubricant retention.


Depending on customer requirements, a component may be super finished as a standalone process or shot peened followed by super finishing which is the C.A.S.E. process. 

How Vibratory Superfinishing Works

SuperfinishingSuper finishing consists of immersing parts in a vibrating bowl charged with properly sized media. A weak acid is utilized to soften part surface such that contact with vibratory media removes asperities such as grinding and machining lines while retaining low spots for lubricant retention.


The process continues to progressively remove asperities while leaving valleys until the desired surface finish is achieved. Prior to completing the process, parts are neutralized so there are no detrimental effects from the acid.

Applications for Vibratory Superfinishing

C.A.S.E Isotropic Superfinishing

The “peak to valley” of the shot peened finish is ~ 2.9 microns. After isotropic finishing, performed as part of CASE, this improves to ~ 0.6 microns

  • Gears
  • Transmission gears and shafts 
  • Bearings
  • Cams and followers
  • Journals

Key Benefits of Vibratory Superfinishing

  • Optimum surface roughness and stress characteristics 
  • Surface reduction to mirror like finishes
  • Improved contact/surface fatigue 
  • Reduction in lubricant temperature 
  • Reduced transmission noise
  • Prevents micro and macro pitting 
  • Finishes suitable for microbiological cleansing and sterilization 
  • Good rounding ability to sharp edges for ease of handling and assembly

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