Integrally formed stamped sheet-metal blades having 3D structure

Integrally formed stamped sheet-metal blades having a 3D structure, comprising:

• an outer diffuser formed as a hollow dish having a plurality of 3D outer vanes extending radially outward, each outer vane including from inward to outward an outer vane root and an outer vane body which bends at an angle against the outer vane root, the outer vane roots forming a center opening, the outer vane body having an outer vane leading edge and an outer vane trailing edge;
• and
• an inner diffuser formed as a hollow dish having a plurality of 3D inner vanes extending radially outward, each inner vane including from inward to outward an inner vane root and an inner vane body which bends at an angle against the inner vane root, the inner vane roots forming a center hub opening, the inner vane having an inner vane leading edge and an inner vane trailing edge,
• wherein the inner vane root of the inner diffuser engages with the outer vane root of the outer diffuser for the outer diffuser and inner diffuser to form an integral sheet-metal blade assembly when the center hub opening is mated against the center opening.