Sandpaper, as one of the most common coated abrasive products, is essential for polishing. Sandpaper can be used to polish wood, metal, and other surfaces to make them smooth and flat. It is usually made by bonding abrasive materials onto paper, and different sandpaper types are selected based on different grinding materials. So how is sandpaper made?


1. Substrate printing


Sandpaper, as its name suggests, is a combination of "sand" and "paper". However, the "paper" here as the base material is not our common A4 white paper or Kraft paper, but such a large roll of special Kraft paper, which is unfolded and printed on one side with information parameters such as product function index and brand name.


2. Surface coating


Now we need to apply the entire surface of resin adhesive to the other side of the paper that is not printed


3. Electrostatic sand planting


Place the adhesive coated side of the substrate downwards and send it into the electrostatic zone. The high temperature and humidity here create an environment where sand particles can adsorb onto the substrate with static electricity.


The conveyor moves the prepared sand particles to the drum, and the static electricity on the sand cloth forms an electric field with the ground. When the sand cloth passes through the grinding sand particles in the air, it is sucked onto the sand cloth due to the effect of static electricity. In order to absorb enough sand particles, the sand cloth will repeatedly enter the electrostatic chamber.


The sand particles will be poured into the conveyor belt like a waterfall, and then transported to the bottom of the substrate.


4. Uniform adsorption


Applying an electric field to the sand will trigger a small sandstorm. When the sand flies into the air, it will be stuck to the substrate coated with Hot-melt adhesive


After coming out of the electrostatic area, sand particles have been evenly attached to the Hot-melt adhesive


5. Baking and shaping


Send the sandpaper to the oven and gradually heat it up, which will allow the sand particles to shape on the adhesive


6. Composite adhesive layer


Apply a layer of resin on the rough surface of the sandpaper to make the "sand" and "paper" bond more tightly, and bake again


7. Cutting shape


Cut the sandpaper into the desired shape according to the usage scenario


8. Factory packaging


Count the sheets according to the packaging requirements, pack them, and a box of sandpaper will be completed


The production process of sandpaper may seem simple, but there are still high technical requirements for the use of sandpaper in high-end applications