RAPID PROTOTYPING

Rapid Prototyping (RP) can be defined as a group of techniques used to  quickly fabricate a scale  model  of  a  part  or  assembly  using  three-dimensional computer  aided  design  (CAD) data. 

Rapid  Prototyping  has  also  been  referred  to  as  solid  free-form manufacturing,  computer automated  manufacturing,  and  layered manufacturing.  RP  has  obvious  use  as  a  vehicle  for visualization. In addition, RP models can be used for testing, such as when an airfoil shape is 

put  into  a  wind  tunnel. RP  models  can  be  used  to  create  male  models for  tooling,  such  as silicone rubber molds and investment casts. In some cases, the RP part can be the final part, but  typically  the  RP  material  is  not strong  or  accurate  enough.  When  the  RP  material  is suitable,  highly convoluted  shapes  (including  parts  nested  within  parts)  can  be  produced 

because of the nature of RP.

The reasons of Rapid Prototyping are

• To increase effective communication.
• To decrease development time.
• To decrease costly mistakes.
• To minimize sustaining engineering changes.
• To extend product lifetime by adding necessary features and eliminating redundant features early in the design.

Rapid Prototyping decreases development time by allowing corrections to a product to be made early in the process. By giving engineering, manufacturing, marketing, and purchasing a look at the product early in the design process, mistakes can be corrected and changes can be made while they are still inexpensive. 

Methodology of Rapid Prototyping

The basic methodology for all current rapid prototyping techniques can be summarized as follows:

1. A CAD model is constructed, then converted to STL format. The resolution can be set to 
minimize stair stepping.
2. The RP machine processes the .STL file by creating sliced layers of the model.
3. The first layer of the physical model is created. The model is then lowered by the thickness 
of the next layer, and the process is repeated until completion of the model.
4. The model and any supports are removed. The surface of the model is then finished and 
cleaned.