Discrete particle system:

• Discrete particles are powdered particles which are graded into a relatively uniform grade, size.

• The fiber particle gives better quality but there will be problem if the dimensions get too small in terms of controlling the distribution and dispersion.

• Polymer powders that have thermo plastic behavior are used because it can be melted and again re melted to join the layers on each other.

• In this case, heat source like UV laser is used to melt the powder.

Fig. Discrete particle system.

3D systems stereo-lithography (SIA)

Fig. stereo-lithography process.

• Stereo lithography is most commonly used for rapid prototyping.

• These systems build shapes using light to selectively solidify photo curable resins.

• A stereo lithography machine converts 3D (AD data of physical object into vertical stacks of slices.

• A low- powder ultraviolet laser beam is carefully traced across a container of photo curable liquid polymer, producing a single layer of solidified resins i.e. 1st slice of the object under construction.

• The layer beam is guided across the surface drawing a cross sectional pattern in X-Y plane to form a solid section.

• The initial layer is then lower incrementally by the height of next slice.

• A re-coating blade passes over the surface, ensuring that a consistent layer thickness is achieved.