1. The petroleum refineries transport powder or liquid synthetic rubber to eraser factories. If the natural rubber is needed, there will come a whole solid piece of rubber, so the workers must shatter and dissolve it first.
2. Mix the rubber with ground pumice powder (which can make the rubber slightly rougher), iron oxide (which can make the rubber pink), vegetable oil, sulfur, and other substances.
3. Mix the sulfur with the rubber by heating the mixture to increase the strength of the rubber and make it more durable.
4. Put the soft, hot ingredients into an eraser extruding machine (squeeze them into a die) to make slender rubber sticks, then cut the rubber sticks into small pieces with a knife and transport them to a pencil factory after cooling to make erasers on the top of pencils.
5. Block erasers for alone use are made by injecting a heated rubber mixture into molds of various shapes. Open the molds after cooling and the erasers of various shapes are successfully made. That's the whole process of a rubber eraser making machine makes a rubber eraser.
All above is the production process of the rubber eraser making machine.