FIELD OF INVENTION
The present invention relates to a work piece adaptor/fixture for clamping fir tree root of LP blades on 1-spindle 5-axis machine.
BACKGROUND OF INVENTION
The LP blades of big sizes comes in forging shape having only profile is finished and the root of fir tree freestanding forging blade get machined in the HMC by clamping the finished profile of blade as a reference in a box with the help of low melting material and the tip of blade (which is only projection of profile) get machined in the other VMCs.
And 1-Spindle 5-Axis Machine is known for machining of smaller sizes turbine blades (having T-root, twisted Profile and Shroud) from rectangular bar/blank in single setting. The one end of rectangular bar/blank get clamp on the work piece adaptor (Figure-1) and the adaptor with rectangular blank move inside the machine and other end of blank get clamped with the help of tailstock center and floating clamp for the purpose of machining the blank.

Previously, the LP freestanding blades having fir tree root and did not have intricate design z-shroud instead the tip end of blades had only projection of profile. Now the newer design blades are having fir tree root and having intricate design Z-shroud at tip which is very difficult to machine in single setting in HMC or VMC.
The disadvantage with the previous process that the HMC or VMC are not having proper fixtures to machine the z-shroud of blade in single setting and not able to maintain the critical dimensions of blade shroud as they are related to the axis of root and profile of blade. Machining of Z-shroud of blade in multiple setting in HMC or VMC may result in dimensional variation and poor quality of blade. The inventors noted that the intricate design z-shroud can not be machined in HMC or VMC in single setting and not able to maintain the critical dimensions of blade shroud. And the 5-axis machine can machine the intricate Z-shroud in single setting but clamping inside 5-axis machines are entirely different (Figure-1) which is for clamping rectangular bar only.
A new fir tree root clamping fixture / adaptor is required at headstock in the 5- axis machine so that the z-shroud end of blade can be held at tailstock end with the help, of center and floating clamps in 1-spindle 5-axis machines for the purpose of machining Z-shroud in single setting.

OBJECTS OF THE INVENTION
It is therefore an object of the invention to propose a fixture / adaptor to clamp/hold the fir tree root of LP blades from one side inside the 1-spindle 5-axis machine, which is capable of suitably holding the blade for machining of z-shroud in single setting.
SUMMARY OF THE INVENTION
Accordingly, there is a fixture/adaptor developed and provided at the headstock end inside the 1-Spindle 5-Axis machine to hold/clamp the fir tree root of the LP blade forging in such a way that the extra material at Z-shroud of blade can be easily clamped/hold at tailstock end of machine for the purpose of machining Z- shroud of blade in single setting.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
Figure 1 Schematic drawing of old work piece adaptor.
Figure 2 Schematic drawing of new fixture / work piece adaptor.

Figure 3 Schematic drawing of inventive Fixture / work piece adaptor with blade
clamping inside machine.
Figure 4 Photographs fixture / work piece adaptor. (For reference only)
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION
Earlier, the root of fir tree freestanding forging blade get machine in the HMC by clamping the finished profile of blade as a reference in a box with the help of low melting material and the tip of blade (which is only projection of profile) get machine in the other VMCs. Previously, the LP freestanding blades did not have intricate design z-shroud instead the tip end of blades had only projection of profile. Now the newer design blades are having fir tree root (which can be machine in HMC) and having intricate design Z-shroud at tip which is very difficult to machine in single setting in HMC or VMC as HMC or VMC are not having proper fixtures to machine the z-shroud of blade in single setting and not able to maintain the critical dimensions of blade shroud.
And the 5-axis machine can machine the intricate Z-shroud in single setting but clamping inside 5-axis machines are entirely different as it is for clamping rectangular bar only.

To hold the fir tree root of LP blade at headstock inside the machine in prior art, a new fir tree root clamping fixture / adaptor (Figure-2) is proposed so that the z-shroud end of blade can be hold at tailstock end with the help of center and floating clamps (Figure-3) in 1-spindle 5-axis machines for the purpose of machining Z-shroud in single setting.
Accordingly, a new fir tree root clamping fixture / adaptor were developed and made to hold the fir tree root of LP blade at headstock in the existing machine (figure-3). Now the fir tree root of blade can be hold / clamp at headstock insides the machine.
The fixture is made from a rectangular block. The fir tree groove (4) is made on the block with fir tree cutter in such a way that the center of blade coincide with the center of fixture for referencing purpose. A Clamping lever (2) is hinged at the bottom of fixture (1) to push the blade upward so that every time the blade should come to the same position. The other end of Clamping lever (2) is pushed by a threaded Clamping bolt. And whole fixture (1) is bolted with work piece adaptor of machine. The block of the fixture is of cast iron.
The Z shroud end (9) of blade is having rectangular extra material extended over the z-shroud (9) of the blade and a center hole at the end face of the extended rectangular extra material. The machine’s tail stock have a center pin (10) and two

parallel jaws floating chuck (7). The center Pin (10) at tailstock clamp and align the blade with the help of center hole available at shroud end of blade and additionally the two parallel jaws floating chuck (7) at tailstock (6) of machine clamp the rectangular extended extra material of the blade horizontally. The center Pin (10) and two parallel jaws floating chuck (7) combined together can be called Fixture at tailstock of machine.
The fir tree groove (4) of blade is being hold in the block/fixture having same matching fir tree groove cut on it and the blade is being clamped in the fixture (1) with the force of Clamping lever (2) applied from bottom of fixture (1).
The purpose of floating jaws (7) is to adjust and accommodate the inaccuracy available on the rough surface of the blade end and clamp the blade by adjusting these inaccuracies.
The work piece adaptor at headstock (5) side which is clamping the fir tree groove (4) of blade is shown at left side and the Shroud side of the blade is clamped at tail stock (6) of machine with the help of Center pin (10) and floating chuck (7) which is shown at right side.

WE CLAIM
1. A work piece fixture for clamping fir tree root of L.P. blades on a 1-spindle 5-axis machine, the said fixture (1) comprising;
a block with fir tree grooves (4) made with a fir tree cutter for coinciding center of blade with the center of fixture to create a reference point;
the said fixture bolted with work piece adapter of the machine and held in the jaws (8) of the head stock (5);
a clamping lever (2) hinged at the bottom of fixture (1) for pushing the blade upward to make the grooves of blade being held in the matching grooves of the fixture and clamped;
a center pin (10) disposed in the tailstock (6) of the machine for holding and aligning the blade having a center hole configured at shroud end of the said blade; wherein
a floating chuck with floating jaws (7) is disposed at tail stock (6) end of the machine for holding the z-shroud end (9) of the blade for adjusting and accommodating the inaccuracies of the rough surface of the blade and for clamping the same.

2. The fixture as claimed in claim 1, wherein the block of the fixture is of cast iron.
3. The fixture as claimed in claim 1, wherein the fix center pin is made of mild steel, hardened and ground.