In 3D printing, the parts are printed in succession. Each successive individual part can be monitored, allowing errors to be caught in real time, reducing the overall number of failed parts and wasted materials while increasing consistent quality of the parts produced.
3D Printing Benefits
It's the most cost-effective manufacture. Allows the creation and manufature of geometric impossible for traditional methods to produce, either as a single part or at all.
3d printing allows to build prototypes to test the operation and performance that the parts could have for the injection mold.