Lapping Process- Characteristics, Advantages ,Process Parameter

Lapping is Super surface Finishing Process.

Lapping

Lapping is the method of obtaining a fine finish. Lapping is basically an abrasive process in which loose abrasives function as cutting points finding momentary support from the laps. Following Figure represents the lapping process. Material removal in lapping usually ranges from .003 to .03 mm but many reach 0.08 to 0.1mm in certain cases.

Characteristics of lapping process:

  • Use of loose abrasive between lap and the work piece.
  • Usually lap and work piece are not positively driven but are guided in contact with each other.
  • In order to avoid the repetitive path of the abrasive grains of the lap on the work piece, relative motion between the lap and the work should change continuously.
  • Cast iron is the mostly used lap material. However, soft steel, copper, brass, hardwood as well as hardened steel and glass are also used.
lapping process working diagram
lapping process working diagram

Abrasives of lapping

  1. Al2O3 and SiC, grain size 5~100μm
  2. Cr2O3, grain size 1~2 μm
  3. B4C3, grain size 5-60 μm
  4. Diamond, grain size 0.5~5 V

Vehicle materials for lapping

  • Machine oil
  • Rape oil
  • grease

Technical parameters affecting lapping processes

  • unit pressure
  • grain size of abrasive
  • concentration of abrasive in the vehicle
  • lapping speed

Advantages of lapping

  •  Improves surface finish by eliminating the peaks and valleys. 
  • Create maximum bearing area between the mating surfaces. 
  •  Improves service life of the moving parts which are subject to wear. 
  • Improves geometrical and dimensional accuracies. 
  • There is absolutely no distortion in the component after lapping since no clamping devices are used. 
  • Minimizes the necessity of re hardening hardened parts because of less heat generation. 
  • Accessible flat surfaces of parts of any shape and size and any type of material can be lapped.
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