Blades may be considered to be heart of turbine, and all other members exist for the sake of blades. Without blading, there would be no power and the slightest fault in blading would mean a reduction in efficiency or lengthy and costly repairs.

The following are some of the methods adopted for the production of blades:

1. Rolling - Sections are rolled to the finished size and used in conjunction with packing pieces. Blades manufactured by this method do not fail under combined bending and centrifugal force.
2. Machining - Blades are also machined from rectangular bars. This method has more or less same advantage as that of rolling. Impulse bladings are manufactured by this technique.
3. Forging - Blade and vane surfaces having air foil sections are manufactured by specialist techniques. The simplest way is to determine the profiles required at the hub and tip, and join them by straight, ruled lines. For more accuracy, a profile, at middle to each end separately is obtained. Once the geometry of the family of the ruled lines is established they may be machined in turn by milling machine, rest carefully for each line to generate the shape required in a master blog from which the forging die may be copy-machined. This method ensures the accurate forging of blades to their finished size, requiring only fletting and polishing. The machining of the fir-tree root is often done by broaching, and electrochemical machining may be used in some parts to avoid the conventional cutting processes. In advance method, computers are used to determine the blade shape required by aerodynamic and stress criteria. The computer may then instruct a numerically controlled milling machine to prepare the dies.
4. Extrusion - Blades are sometimes extruded and the roots are left on for subsequent machining. This method is not as reliable as rolled section, because of narrow limits imposed on the composition of the blade material.
5. Cold Drawing - Blades are also cold drawn.

Read More About Construction of Turbine Blades:

• LP stage blading
• Hollow Blades
• Shrouding