Mechanical pencils are made through an automated process in assembly factories. Most pencils are made of plastic and have a hollow barrel, writing tip, eraser, and a built-in lead controlling method. The eraser is usually added to the top end of the pencil and is removed to access the lead barrel. There are two methods of making mechanical pencils: manual assembly of individual parts or using a formed plastic mold.
Before mechanical pencils can be manufactured, there is a design review process. The target consumer must be identified and the key features for the proposed product reviewed. Decisions must be made about the color, texture, and aesthetics of the outer body. At the end of this process, the schematic drawings are completed. These drawings provide the exact measurements for the different components of the pencil, ranging from the barrel size to the mechanism used to control the pencil lead.
In the manual assembly process, these specification details are provided to the different part manufacturing firms so that they can provide the cost and timeline to the assembly firm. The design specifications include details about the different lead sizes that the pencil must be able to accommodate and any other features. The components are manufactured based on these requirements.
The barrel of mechanical pencils must have sufficient space to hold between five and ten individual pencil leads. The barrel can be made from plastic, metal or a combination of rubber and plastic. A mold is created of the required shape and machines are used to produce the barrel.
A metal forming firm completes the creation of the pencil tip and any other metal parts. The tip is manufactured with screw grooves, as this is the most secure method of attaching the tip to the pencil barrel. The lead advancing mechanism is usually metal, and is created by the same firm. These pieces are forwarded to the assembly plant once the order is completed.
An assembler inserts the advancing mechanism into the barrel, checking to ensure that it functions properly. The pencil barrel is added to a conveyor belt, which takes it through a machine that inserts the pencil leads into the barrel. The tip is screwed into the barrel and the eraser is inserted into the top of the barrel. The pencil is then placed into the packaging material and prepared for shipment.
For a fully formed disposable model, a die is created for the barrel, tip, and eraser holder as one piece. The mechanism to move the mechanical pencil forward loaded with lead and inserted into the barrel. The eraser is added at the top of the pencil as a final step before being placed in packaging material and shipped.