Lapping Process | Advantages, Disadvantages, Applications, Types

What is lapping?

Lapping is a finishing process, which is carried out using loose abrasives. In lapping process surface smoothing is achieved by the abrasive grains which are supported by the lap, which acts as a cutting tool shank.

Diagram of lapping process

Advantages of lapping:

• Extreme accuracy of dimensions
• Correction of minor imperfections of shape
• Refinement of surface finish
• Producing close fit between mating surfaces
• It does not require the use of holding devices; therefore, no workpiece distortion occurs.
• Additionally, in normal lapping, less heat is generated than in most of other finishing operations. This minimizes the possibility of metallurgical changes to the machined parts.
• When both sides of a flat workpiece are lapped simultaneously, an extreme accuracy in flatness and parallelism and the relief of inherent stresses can be achieved.

Disadvantages or limitations of lapping:

• It is a slow process
• It is a expensive process

Applications of lapping process

• It is used in Ceramic machining
• It is used in Brittle material machining
• It is used in Glass machining

Types of Lapping

The Rubbing action in lapping can be done manually or with the help of machine. According to it, lapping can be divided into two types.

• Hand Lapping:

In hand lapping process, the work piece is rubbed over the lapping plate manually. In this process, first the plate is coated with the abrasive material which is in the form of paste. Now, the work piece is rubbed over plate by applying a small pressure manually.

• Machine Lapping:

It is used for finishing large quantity of similar parts. This machine involves a rotating lapping plate and conditional rings. Conditional rings provide sits for work piece. This rings rotates and rubs the work piece against lapping plate.

Abrasive particles are provided with suitable medium like liquid or in powder form. This rubbing removes metal in form of microchips and provide super finishing.