Create and edit a manufacturing model in the Manufacture workspace to help with creating manufacturing operations, without affecting the original model in the Design workspace. Changes for ease of manufacture can be made directly within the Manufacture workspace through the manufacturing model contextual environment.
When programming operations on multiple manufacturing models, if at any stage you go back to the Design workspace and make changes to the original model, then those changes transfer across to all the existing and future manufacturing models.
This video explains how the manufacturing model works and shows a common example of when to use it.