The pencil is divided into two parts: the pencil cap and the pencil body. The main decorative materials for the pencil cap are polyester materials, and the manufacturing process includes molding, offset printing, and assembly. The main decorative materials for the pencil body include nitrocellulose pencil paint, printing ink, anodized aluminum foil, eraser, and aluminum ferrule. The manufacturing process includes processes such as pencil board processing, lead core processing, pencil body processing, and finished product decoration.
Pencil board processing involves cutting and sawing logs into blocks, which are then cut into pencil boards using a cutting machine after hydrothermal treatment. The boards are 184mm long, 73mm wide, and 4.8-5.2mm thick. They are then dried by heating (60-120℃) and subjected to high-temperature (130-200℃) denaturation treatment to make the pencil boards soft and easy to sharpen.
Lead core processing: Graphite lead cores are made by mixing graphite and clay in a certain proportion, then mixing them in a kneading machine and a three-roll mill. The mixture is then extruded into lead cores of a specific size (e.g., HB-3H lead cores have a diameter of 1.80-2.10mm) using a core press. These cores are then dried by heating (50-150℃) and fired at high temperature (800-1100℃) to give them a certain mechanical strength and hardness, and finally treated with oil immersion. Color lead core processing is similar to graphite lead core processing, but does not require sintering. There are two processing methods: one is to mix clay, talc powder, adhesive, pigment, oil, and wax evenly, then form and dry them; this is called the mixing method. The other method is to mix kaolin, talc powder, pigment, and adhesive evenly and extrude them into lead cores, or to place the dried lead cores in an oil core container and allow them to fully absorb oil at a certain temperature; this is called the oil immersion method. The pencil manufacturing process involves using a grooving machine to plane the pencil boards to a thickness of 4.1–4.2 mm, creating grooves that accommodate the diameter of the lead core. The lead core and the grooved boards are then glued together using an adhesive. After heating (50–120℃) and drying under pressure for 1–8 hours, the resulting blanks are processed by a planing machine to produce white pencil blanks with a length of 178–180 mm.
The finishing process involves painting and printing decorations on the white pencil blanks, as well as cutting, printing trademarks, attaching erasers and caps, etc., to produce finished pencils with specific specifications, colors, and patterns.