Sandpaper is one of the most common coated abrasive products. When we need to polish, we basically cannot do without sandpaper. Sandpaper can polish wood, metal and other surfaces to make them smooth and flat. It is usually made by bonding abrasives on paper. Different sandpapers are selected according to different abrasive materials. So how is sandpaper made? Today, the editor will tell you!
Types of sandpaper
Sandpaper can be divided into sandpaper and sanding belt according to its shape. Sandpaper is like the paper we use, which can be torn directly by hand. The reverse side of the sanding belt is usually cloth, which is suitable for use with a grinding machine and is more durable.
According to different abrasive materials, it can be divided into dry sandpaper, water sandpaper, and sponge sandpaper.
Dry sandpaper is also called dry sandpaper. It uses synthetic resin as an adhesive to paste silicon carbide abrasive particles on latex paper. The gap between the sand particles is large, and the ground debris will fall off automatically. It is not easy to cause clogging during the grinding process to affect the grinding. It is suitable for grinding metal surfaces, wood surfaces, putty and coatings. Dry sandpaper generally uses special kraft paper or latex paper.
Water sandpaper is also called water-abrasive sandpaper, water-resistant sandpaper. The abrasive material is silicon carbide, and the paper base is generally kraft paper. The texture of water sandpaper is relatively fine, the gaps between the sand grains are small, and the debris particles ground out are also small. When used with water, the debris will be washed out, which will not affect the sharpness of the sand grains. Water sandpaper is suitable for grinding things with fine textures, and is suitable for post-processing. It is used in stone grinding, hardware processing, mold processing, automotive grinding and other industries.
Sponge sandpaper is also called sponge sand block. It is based on sponge and abrasive sand is implanted on the sponge. It is soft and elastic, has strong water absorption, and can be reused. It is widely used in solid wood processing, metal stainless steel processing, machinery manufacturing and other surface grinding and polishing.
Manufacturing of sandpaper
Sandpaper is the most common grinding tool. It is mainly made of thousands of abrasives on the surface. Do you know how the sand on the sandpaper is fixed? Let's learn about the manufacturing process of sandpaper.
1. Substrate printing
Put the manufactured roll sandpaper substrate on the machine and open it. The substrates used for sandpaper include cloth, paper and composite substrates. After the sandpaper substrate enters the machine and passes between two rollers, the specifications, dimensions, trademarks and other information will be printed on the back of the sandpaper.
Abrasive mesh
The abrasives on the sandpaper are all artificial sand particles, mainly silicon carbide and aluminum oxide. Their common characteristics are high temperature resistance and wear resistance, which makes them ideal materials for making sandpaper.
2. Surface glue coating
Now, the other side of the paper without printing is coated with resin glue
The rubber roller with printing function prints the cured adhesive on it at the same time. At this time, the computer will measure the density of the sandpaper coating to achieve the best curing effect of the adhesive, and then perform electrostatic treatment. The sandpaper coated with adhesive is sent to the electrostatic chamber.
3. Electrostatic sand planting
The surface of the substrate coated with glue is facing downward and sent to the electrostatic area. The conveyor moves the prepared sand grains under the reel. The static electricity on the sandpaper forms an electric field with the ground. When the sandpaper passes by, the abrasive sand grains in the air are attracted to the sandpaper due to the static electricity. In order to absorb enough sand grains, the sandpaper will repeatedly enter the electrostatic chamber.
The sand grains are moved under the reel. The static electricity on the sandpaper forms an electric field with the ground. When the sandpaper passes by, the abrasive sand grains in the air are attracted to the sandpaper due to the static electricity. In order to absorb enough sand grains, the sandpaper will repeatedly enter the electrostatic chamber.
The sand will pour into the conveyor belt like a waterfall, and then transport them to the bottom of the substrate.
Electrostatic sand planting is sucked up by the electrostatic electric field force. The advantage is that the distribution of sand is more uniform. The disadvantage is that if the sand particles are too large, they cannot be sucked up. The larger the sand particles, the greater the electric field force, which means increasing the voltage and current, and the production cost also increases.
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 attached to the substrate coated with hot melt adhesive.
After coming out of the static zone, the hot melt adhesive is evenly attached with sand particles.
5. Baking and shaping
Send the sandpaper to the oven and gradually increase the temperature, which will allow the sand grains to be fixed on the glue, and then the sandpaper is wound onto the reel.
6. Re-glue layer
Apply a layer of resin on the rough surface of the sandpaper to make the "sand" and "paper" combine more tightly, and bake again.
7. Cutting shape
Cut the sandpaper into the required shape according to the usage scenario.
8. Factory packaging
Count the number of sheets according to the packaging requirements, pack them, and a box of sandpaper is ready.
The sandpaper we buy is coarse or fine. The mesh number is generally used to represent the coarseness of the sandpaper. The mesh number is usually printed on the back of the sandpaper. The mesh number is determined by the number of sieve holes on a length of 1 inch, which means how many meshes there are. The larger the mesh number, the more sieve holes per inch, and the finer the abrasive, and vice versa. For example, 80 mesh means that there are 80 sieve holes on a 1-inch screen, so the 80 mesh marked on the sandpaper means that the abrasive used in this sandpaper is sieved out of an 80-mesh screen. The ancients said: If you want to do your job well, you must first sharpen your tools. Only by choosing qualified sandpaper can you complete the grinding with half the effort. The appearance requirements must not have sand shortage, too thick glue, uneven sanding, neat edge cutting, no burrs, etc., and the corresponding type of sandpaper should be selected according to the object being polished.
Nowadays, sandpaper is not only a tool for polishing, but also used to create various beautiful sandpaper paintings. The rough surface of sandpaper is conducive to the adhesion of pigments, and the darker base color can bring out bright colors. Sandpaper has found a stage to realize its potential.
The production process of sandpaper seems simple, but the use of sandpaper in high-end application fields still has very high technical requirements. If you have any questions about sandpaper polishing, you can leave a message to tell the editor!