I wanted to know , what is SAP PP MANUFACTURING WORKBENCH
Thats not 'SAP PP MANUFACTURING WORKBENCH'
The Engineering Workbench is an environment for maintaining product structures and operations.Its capabilities far exceed those of the conventional maintenance of bills of material and routings.
The most important objects in the Engineering Workbench are BOM items and operations. Views of these objects are available that present the conventional structures of bills of material and routings.
In addition to this, other views are now available that were previously not possible. All of the maintenance functions, such as Create, Change and Delete are supported on all of these views.
I too have never heard of the "SAP PP MANUFACTURING WORKBENCH".
There is a similar workbench in iPPE (DIMP addin) that is a bit more comprehensive than the basic Engineering Workbench.