Figure 74 is a schematic diagram of a manufacturing process. In the centre of the diagram there is a platform mounted on a piston. Next to the platform there is a direction arrow pointing down. The object being manufactured is located on the platform and it appears to be encased in a rectangular shaped block of material that consists of layers and vertical divisions. The block is partly transparent to allow the manufactured part to be seen. The vertical divisions can be seen in all sides of the block. The block is labelled 'Layered part and support material'. The top surface of the block has a chequered pattern surrounding a sectional shape of the object being manufactured. This surface is labelled 'Part layer outline and crosshatch'. This surface is also labelled 'Current layer'. On one side of the platform assembly there is a roll of sheet labelled 'Material supply roll'. This roll is below the level of the platform. From this roll a continuous sheet of material rises vertically to another roller which turns the sheet horizontal. The sheet now crosses over the platform and becomes the current layer of the object being manufactured. The sheet continues away from the platform. In this section of the sheet there is a rectangular hole the same size as the block on the platform. This hole is labelled 'Previous layer'. This section of the sheet has also reached another roller which turns it vertically downwards where it ends up on another roll labelled 'Waste take up roll'. A cylinder, labelled 'heated roller', is shown rolling over the current layer. Situated above the tank is a laser assembly similar to that in Figure 72 but with the addition of a cube-shaped optic head that can move in both x and y directions. This directs a laser beam down on to the exposed top surface of the current layer.

 4.9.2 Processes and materials