Rapid Injection Mold (RIM) describes a process that is the result of combining Rapid Prototyping techniques with conventional tooling practices to produce a mold quickly or parts of a functional model from CAD data in less time and at a lower cost relative to traditional machining methods. Rapid Tooling can act as a bridge to production injection molded parts.Rapid Tooling (RT) typically, either uses a Rapid Prototyping (RP) model as a pattern or uses the Rapid Prototyping process directly to fabricate a tool for a limited volume of prototypes.
Expensive tooling cost can be well justified just when the production quantity is massive. Actually the way to produce tooling quicker and more economically, especially for small quantity manufacturing becomes a significant question. Additionally, in the product development cycle, requires always some intermediate tooling to produce a small quantity of prototypes or functional tests, samples for marketing, evaluation purpose, or production process design. RT becomes more and more important to nowadays manufacturing industry.The main advantages are tooling time is much shorter than for a conventional tool. Time to first articles can be less than one-fifth that of conventional tooling, tooling cost is much less than for a conventional tool. Cost can be below five percent of conventional tooling cost.The main challenges are tool life is less than for conventional tools and tolerances are wider than for conventional tools.

Advantages of rapid tooling for manufacturing:
Shorten the Tooling Lead-Time - Normal development time is shortened from months to a few days or weeks. 
Low Cost - reduced Cost allowing real trials affordable.
Allows functional test of parts on initial design stage.
Data CAD Direct Transfer - Many imperfections due to drawings misinterpretation can be avoided using the original CAD model all through the RP process and then along to RT process.