@Cristian_Lorenzin, in addition to Naveen’s suggestion, if you’d like to learn more about using the Transfer Learning method, please take a look at Coral documentation 4 on this subject using the new weight imprinting API and code samples 6.  If the metal parts are large and changing orientation is obvious, this approach could also work using the Coral Dev Board HW and learning to recognize size and orientation changes on the fly using on-device AI/ML.
Thanks!