The refills of colored pencils do not actually contain any lead, but are composed of pigments, minerals and binders.
First, some companies produce colored pencil refills that can be added with water to create a watercolor effect after drawing. The manufacture of colored pencils begins with a combination of pigments. Each shade has a specific formula, and the different ingredients are accurately weighed according to the formula of the color. Boil a measured amount of water and additives, then add a binder made from gum, twigs or wax according to the recipe. These ingredients expand in the hot water to form a paste. Workers then mix pigments into this paste.
Second, the next machine processes the paste so that its color becomes a more intense tin block, and then the fine blocks are sent to a cylinder for compression, and then sent to an extruder. . The extruder integrates the paste into long strips of refills of the same diameter. A machine cuts long strips of lead into pencil lengths. Now that the refills are unusable, they are put into a vat filled with a chemical mixture of waxes that covers and penetrates the refills. The wax is used as a dye, for example, the wax here is red, and when you transfuse blood, it wipes off and sticks to the paper with the pigment. After the refill is completed, the factory sends random samples to the quality control department for testing. The test items include a breakage test and a durability test in which the writing length of each refill must reach 100 meters.
Third, the pen body is made of cedar wood. This machine measures the refill slot, then applies a thin layer of adhesive strips on the surface, and passes it through a wheel that places the refill. The lead is then sandwiched by another row of machines that lays the grooved slats over the top, the next machine carves out the six-pointed star and then cuts the pencil open. The pencils pass one by one through the vat containing the paint, now matching their outer color with the lead. After the paint dries, a thermal printer stamps the company name and color number onto the wood and fills it in with color film. Then the writing end of the pencil is tipped through a grinding wheel, and finally the end without the film tip is varnished. If it is not white, it is the same color as the pen core. The factory sends pencils of the same color to the packaging area. When the pencils are put into the ceramic plate, workers check each pencil. If there is no problem, it can be packaged and sent to the warehouse, so that the colored pencils are manufactured.