Metallographic grinding and polishing is the first step of mechanical removal of materials.

Proper grinding can remove damaged or deformed surface materials, and also limit the deformation of other surfaces. The purpose of grinding is to obtain the plane with the least damage, and at the same time, these damages can be easily removed by polishing in the shortest time.

The fixed abrasive particles can be used to remove the material, but the sample material chips will be generated. The process of removing the material chips with sharp abrasive particles can minimize the deformation of the sample and achieve the highest removal rate.

Grinding can be divided into 2 processes:

Flat grinding: This is usually the first step in the grinding process. Regardless of the initial condition of the sample and the previous treatment, flat grinding ensures that all sample surfaces remain similar. In addition, when processing several samples in the same sample holder, special care must be taken to ensure that these samples are at the same level or "flat" before starting the next step, i.e. fine grinding. For plane grinding, in order to obtain a higher uniform material removal rate, reduce the grinding time and obtain the maximum straightness, it is better to select completely fixed particles with relatively large size. The proper PG surface can provide a sample with perfect flatness, thereby reducing the preparation time spent in the subsequent fine grinding steps. In addition, some surfaces can retain good edges. During grinding, new abrasive particles will be released to ensure consistent material removal rates.

Fine grinding: Fine grinding can provide a surface with less deformation, and can easily remove the resulting deformation during polishing. Due to the defects of the abrasive paper, an alternative fine grinding composite surface is provided to improve and promote fine grinding. By using 15, 9 and 6 μ M size particles to achieve high material removal rate. This applies to hard composite abrasive discs (rigid abrasive discs) with surfaces made of special composite materials. This allows the continuous supply of emery to be embedded in the surface for fine grinding operations. Using these discs, a sample surface with excellent straightness can be obtained. The use of diamond abrasives on fine abrasive discs ensures consistent material removal rates for both hard and soft phases. Not only does the soft phase have no tailing, but the brittle phase has no chips, and the sample can maintain the best straightness. The subsequent polishing steps can be completed in a very short time.