Pencils are machined as follows:
Pencil board processing:
1. Unfold and cut logs, cut square and saw them into blocks. After hydrothermal treatment, they are cut into pencil boards by a board cutter. The plate is 184 mm long, 73 mm wide and 4.8-5.2 mm thick. The pencil board is softened and easy to roll by heating (60-120 C) drying and denaturation at high temperature (130-200 C).
2. The lead core is made of graphite and clay in a certain proportion. After mixing by kneading machine and three-roll press, the lead core with a certain size (such as HB-3H lead core diameter 1.80-2.10mm) is extruded by core press. The lead core is dried by heating (50-150 C) and roasted at high temperature (800-1100 C). The lead core has a certain mechanical strength and hardness. Finally, it is made by oil immersion treatment. The processing of color lead core is similar to that of graphite lead core, but it does not need sintering.
3. There are two ways to process lead core: one is to mix clay, talc powder, adhesives, colors, grease and wax evenly, then make them into mixing method, which is called mixing method; the other is to mix ceramic clay, talc powder, colors and adhesives evenly and then extrude them into lead core or put the dried lead core in the oil core container to absorb grease adequately at a certain temperature. It is made by oil immersion method.
4. Pencil rod is machined by grooving machine, which cuts pencil board into grooves with thickness of 4.1-4.2 mm and core grooves corresponding to the diameter of lead core. Then lead core and pencil board are glued together by cementing agent, heated in clamping state (50-120 C) and dried for 1-8 hours, and then white pencil with length of 178-180 mm is machined by the planer.
5. Appearance decoration process uses white-pole pencils for painting and printing decoration, as well as cutting, printing trademarks, rubber heads, pen caps and other processing, to make them into finished pencils with certain specifications, appearance color and pattern patterns.
