The ultimate goal of metallographic sample preparation is to prepare a flat mirror surface for observation after corrosion or direct observation. The importance of grinding and polishing is obvious. Polishing is the last step in the sample preparation stage, and it is also the most important and critical step.

Polishing requires the use of a polishing disc and a polishing liquid. The polishing liquid provides abrasive particles, and the polishing disc provides a grinding surface by storing and holding abrasive particles; the polishing disc stores abrasive particles to extend the service life of the abrasive particles; the holding of abrasive particles uses small scratches to remove the rough scratches on the surface of the sample.

The polishing disc surface in the traditional sense is flannel cloth, so-called a flannel cloth and a bottle of polishing powder can conquer the world. However, with the increasing specialization and refinement of metallographic sample preparation, such days are gone forever, especially after the automatic grinding and polishing machine can achieve precise control of loading pressure, grinding trajectory, polishing liquid dripping amount, etc., the diversification of grinding and polishing disc surfaces is particularly important. A lot of experience has indeed shown that polishing cloths of different materials are indeed targeted to sample materials, especially alloy products.

There are many ways to classify the materials of polishing discs::

1. Classify by material

Material classification is the most common method. The mainstream disc materials are: flannel, canvas, wool, acetate, silk, rubber, etc. The scratch removal characteristics of each material are different. For example, wool can cover many steel parts, while acetate is more suitable for aluminum alloy materials. In addition, due to the different abrasive storage characteristics of different fabrics, it is also necessary to match the appropriate disc speed and sample holder speed to achieve a balance between scratch removal and consumables.

2. Classify by textile process

For textile fabrics, there are fine spinning and woolen spinning, as well as fine knitting and coarse knitting; for flannel, there are short flocking and long flocking. Different weaving processes determine the wear resistance and looseness of the fabric, and directly affect the polishing effect and service life.

3. Classification by compression deformation

During polishing, the positive pressure of the sample will be transmitted to the polishing disc surface, and the disc surface material will deform. This deformation will have a greater impact on the edge rounding, especially for soft samples, and discs with less deformation should be used as much as possible. The deformation of the disc surface depends on the material itself and the textile process.

The magnetic disc fixing method is simple and convenient, easy to take and put, and has received more and more praise, so the polishing disc should also be transferred to the steel back. There is usually an isolation layer between the glue layer and the fabric. There are many professional tricks for the isolation layer technology of different manufacturers.

In summary, there is a lot of knowledge hidden in a small disc surface, and the choice of disc surface is very particular. The main task of the metallographic technician is to constantly explore and optimize various combinations, and then solidify them and share them with others. This process is destined to be repeatedly explored and tried, and it is inevitable to take detours and waste time and energy. The most worry-free way is to outsource this work to a professional company. More professional domestic companies, such as Shanghai Truer, have more than ten years of experience in commissioned sample making, have accumulated a large amount of sample making information, and established a special database, which can quickly obtain the best sample making solution.

All microscopic analyses are the accumulation and crystallization of countless details, and the same is true for metallographic analysis. Even the most insignificant errors may create obstacles for subsequent observations. Industry practitioners must be in awe and pursue perfection.

Shanghai Truer Company has been deeply involved in the metallographic testing industry for decades, and has long practiced the concept of exquisite metallography. It is a leading metallographic solution provider in China. Truer takes international giants as benchmarks, faces difficulties, concentrates on research, and overcomes key equipment and consumables that restrict the development of the industry, creating a complete metallographic industry chain that integrates equipment, consumables and sample preparation training; the company is equipped with a cutting-edge metallographic laboratory and has a team of highly qualified experts. For more than ten years, it has provided metallographic analysis and sample preparation training services to thousands of customers, and provides customized metallographic laboratory solutions.

If you have any metallographic questions, you can get in touch with them to get the information you want.