Pencil processing is as follows:

Pencil board processing:

The logs are unwound and cut, square-sawed into wooden blocks, and then cut by a board cutting machine after hydrothermal treatment. into pencil board. The board length is 184mm, width is 73mm, and thickness is 4.8~5.2mm. Then it is heated (60~120℃), dried and denatured at high temperature (130~200℃) to make the pencil board soft and easy to curl.

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2. Lead core processing Graphite lead core is made of graphite and clay in a certain proportion. After being mixed by a kneading machine and a three-roller machine, The lead core of a certain size (such as HB~3H lead core with a diameter of 1.80~2.10mm) is extruded through a core press, dried by heating (50~150℃) and roasted at high temperature (800~1100℃) to make it It has certain mechanical strength and hardness, and is finally made by oil immersion treatment. The processing of color lead core is similar to that of graphite lead core, but sintering is not required.

3. There are two ways to process lead core: one is to mix clay, talcum powder, adhesive, color, grease and wax evenly, then shape and dry it, which is called mixing. method; the other is to mix china clay, talcum powder, colorants and adhesives evenly and then squeeze it into a lead core or place the dried lead core in an oil core container and use it at a certain temperature. It is made by fully absorbing grease, which is called the oil immersion method.

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4. For pencil shaft processing, use a planer to plan the pencil board into a thickness of 4.1~4.2mm, and have a groove that is suitable for the diameter of the lead core. The groove plate of the core groove is then glued together with the lead core and pencil board using glue, heated (50-120℃) and dried in a clamped state for 1-8 hours, and processed by a planing machine to a length of 178-180mm. white pencil.

5. Appearance decoration processing: The white pencil is painted and printed, as well as cut, printed with trademarks, installed with eraser heads, pen caps, etc., to make it into a pencil with certain specifications, appearance colors and patterns. Finished pencil.

Extended information:

1. Is pencil lead poisonous?

In fact, pencil lead is not poisonous. Lead is toxic, and the main raw materials for making pencil lead are graphite and clay, so pencil lead is non-toxic.

The main components of pencil lead are graphite and clay. Graphite is a scaly solid with metallic luster. There are carbon-carbon chemical bonds in it. There are van der Waals forces between layers. The carbon-carbon chemical bonds are It is very stable and difficult to destroy, which is why diamond and graphite are both composed of carbon, but their physical properties and prices are very different. Nothing in the human body can destroy carbon - Carbon chemical bonds, so it is definitely safe to say that pencil lead is safe (unless the clay added in it is harmful to human health).

2. Is there any metal poison in the pencil shaft?

The appearance of the pencil shaft is wrapped with a mold or pencil paint technology is used. On the one hand, it can protect the pen shaft, and on the other hand, it can increase the appearance. However, the pigments will contain trace amounts of heavy metals. A small amount of contact will not have an impact, but the bite It is still inappropriate to put the pen barrel in your mouth.