1. The petroleum processing plant transports the powdered or liquid synthetic rubber to the rubber manufacturer. If you want to use natural rubber, it is a solid big piece, and the workers must first pulverize and dissolve it.
2. Mix the rubber with the ground pumice powder (which can make the rubber slightly rougher), iron oxide (which can make the rubber turn pink), vegetable oil, sulfur and other substances.
3. Heat the mixture to mix the sulfur with the rubber to increase the strength of the rubber and make it more durable.
4. Feed the soft, still hot material into the press (squeeze into a die) and make a thick and thin rubber stick. Use a knife to cut the rubber stick into small pieces, wait for it to cool, and then transport it to the pencil factory to make an eraser on the pencil.
5. The block eraser used alone is made by injecting the heated rubber mixture into various shapes of the mold. After cooling, open the mold and the erasers of various shapes come out.