The given diagram depicts the process of making pencils.
Overall, the process commences with two parallel manufacturing lines, one for making pencil leads and the other for pencil cases. The two sub-processes continue separately until leads and a wooden slat are obtained. The pencils are the outcome of assembling the resulting products of the sub-processes and shaping them afterwards.
The procedure of making the pencil leads begins with forming a graphite dough out of mixing ground graphite, clay and water. After that, the resulting dough is placed in a container that presses the dough and forms graphite rods. The next stage is cutting the rods in order to achieve the leads in the same-length. At this stage, the leads are not dry yet so they are put in the oven at 800 degrees celsius to be dehydrated. The process continues with adding the resulting dried leads to the wooden slat produced during the parallel sub-procedure.
Simultaneously, the sub-process of making the pencil cases takes place. The first stage is converting a piece of wood into a slat and cutting the grooves in it. The grooves are cut to be filled with the dried leads. Once the leads are dried in the oven, they are glued into the grooves in the wooden slat. This is followed by putting another carved wooden slat on top of the result of the previous stage to form a sandwich of slats, which are then cut into pieces. The pencil pieces are shaped by a shaping machine to become a smooth, finished pencil.