Metal 3D printed cavity inserts are not actually «soft». We use the term «soft» to distinguish with the nowadays standard through hardened H13 (1.2343 or Orvar from Uddeholm). Here we reference cavity inserts made of stainless steel 17-4PH with the following specifications compared to P20 (1.2311 or Impax from Uddeholm) common tool steel:

In order to optimize the cost of the printed inserts, post-printing machining should be kept to minimum
At least, insert fitting surfaces, parting surfaces and tight tolerance surfaces must be machined.
Component surfaces, if surface quality can be accepted -i.e. without special aesthetic requirements-, then machining is not required.
With BMD printed metal components, post printing machining is a fast and economic procedure, as only a single pass final finishing is required.

In normal toolmaking, cavity inserts manufacturing has the following workflow:

Workpiece Purchase>>Pre-roughing>>Roughing>>Stress Releaving>>pre-finishing>>Through Hardening>>Finishing>>Polishing.

It is now possible to integrate metal 3d printing into the toolmaking process with many different printing technologies (DMLS, BMD etc). However, although printed part tolerances and surface quality varies between different technologies, none of the printing technologies meets the standards for toolmaking. Post printing machining operations are always necessary.

So, by 3d printing we do not produce a finished cavity insert, but an 'enhanced' workpiece.

'Enhanced' workpieces from all printing technologies have only a minimal stock left to machine, but with BMD printing technology we have an additional advantage. After sintering we get an almost stress releaved metal part with minimal hardening warpage. So, with BMD there is no need for increased workpiece stock to compensate for stress releaving/hardening warpage.

The workflow is tranformed to:

Metal 3D Printing>>Thread Cutting>>Through Hardening>>Finishing>>Polishing.