Comparative Analysis Of The Application Of Old Sandpaper And New Sandpaper？

The reasons are as follows:

Taking the most common silicon carbide sandpaper as an example, the production of sandpaper uses adhesives (usually resins) to fix sharp abrasive particles on the paper base. Since the grinding of sandpaper is a micro-abrasive process, the damage or shaping rheology caused by the spent abrasive is greater than that of sharp abrasive particles. From the cross-sectional comparison diagram of new and old sandpaper below, it can be clearly seen that the abrasive on the new sandpaper is sharply protruding. After a period of use, the abrasive will be broken, the edges and corners will be cut off, and the abrasive particles will be completely in the bonding layer. . At this time, the material removal rate is slower, and the chance of rubbing contact increases.

The wear marks in the picture below were obtained by grinding with new and old sandpaper. Which do you think is the better-prepared surface? Is that from the new sandpaper?

Just a hint for you: the wear marks on new sandpaper will be clearer, with a three-dimensional image, with one wear mark superimposed on top of another. The wear marks of the old sandpaper no longer have a clear three-dimensional shape and appear in a plane; in this case, the depth of the deformed layer of the sample will increase exponentially. It is only because the wear scars are more planar and the sample more reflective that it gives the illusion of a more successful preparation.

Believe you already know the correct answer. Therefore, during the grinding process, don't be afraid of scratches. The clear, three-dimensional, and regular blemishes brought by the new sandpaper represent the successful removal of the material. Replacing the sandpaper in time will help you get samples with less residual damage.