FIELD OF INVENTION
The present invention relates to a single layout holding method for 5-axis multi-
patch scoop milling of steam turbine stationary bladed rings from a single forging.
BACKGROUND OF THE INVENTION
In Super Critical Steam Turbines of rating 660MW and 800MW, Turbine HP and
IP Modules are designed and implemented one stage of single piece Diagonal
Stationary Bladed Ring, comprising of inner & outer casings with integral blades, for
better performance. These integral bladed rings are to be machined from single forging
through 5-Axis machining. These components are complex requires stringent
dimensional accuracies and the high surface finish requirements. Presently, these Rings
are manufactured through either - assembling the machined blades with spacers or
welding the blades between Inner and outer rings. In both the cases the blades are
machined separately and assembled together in the inner and outer Rings to make a
single Stationary Ring. But in the new requirement of 660/800/1000 MW Steam
Turbines, the Integral bladed ring is to be machined from a single forged blank. This
makes above component more complex to manufacture from a single piece and in a
single layout.

During the search of the patents (US 8464425, US 2480807, US 2633776, US
3108782) it is observed that, presently the 5-Axis machining is carried out in a single
layout of the Bladed disks (Blisks), in which the blades are integral to the hub of the
rotor but they are open on the shroud side. There is no patent found in the search, that
the total closed Bladed Ring of the Steam Turbine is 5-Axis scoop machined in a single
layout on the 5-Axis machine with rotary indexing table and both sides tilting head, as
proposed in the current invention.
The single layout Scoop Milling Technology is developed for the Diagonal
Stationary Bladed Rings. These rings are machined on the Chiron 5-Axis Machine with a
rotary indexing table with both sides tilting head configuration. The multi-patch 5-Axis
CNC part programs have been developed using the UG-NX and MAX-SI CAM packages
for roughing, semi finishing and finishing of single forged blanks. The special Modular
and Bulb/Lollypop Cutters are used for the intricate surface machining.
OBJECTS OF THE INVENTION
Therefore, it is an object of the invention to propose a single layout holding
method for 5-axis multi-patch scoop milling of steam turbine stationary bladed rings

from a single forging, which is capable of achieving better dimensional quality, of
reducing overall manufacturing cycle time avoiding multiple fixtures, layouts and their
mismatches.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1 : Shows a view of the single layout 5-Axis multi-patch scoop milling of
the bladed ring from the Inlet passage on the 5-Axis machine with rotary indexing table
with both sides tilting head configuration.
Figure 2 : Shows a view of the single layout 5-Axis multi-patch scoop milling of
the bladed ring from the Outlet passage on the 5-Axis machine with rotary indexing
table with both sides tilting head configuration.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE
INVENTION
The present invention relates to the special job holding fixture and methodology
used for the multi-patch 5-Axis scoop milling of the Stationary Bladed Rings of the
Super Critical Steam Turbines from a single forged blank on the suitable 5-Axis machine
tool with rotary indexing table with both sides tilting head configuration.

In the embodiment of the present invention, the single layout method consists of
5-Axis machine table 1 which moves in the X, Y and Z directions linearly. On this table
1, the rotary indexing table 2 is mounted, which rotates about X-axis, Clockwise positive
A angle and counter clockwise negative A angle. And this Rotary Table 2 rotates
continuous + or - 360 degrees and it is a roll over axis. On the Face plate 3 of the
Rotary Table 2, the fixture plate 4 is mounted with help of two locating pins 15. on this
fixture plate 4, the Bladed Ring blank 7 is mounted by locating with the help of two pins
14 which made in the extra holding plate 8 of the bladed ring blank 7. The both sides
tilting head 9 of the 5-Axis machine can rotate about Y-axis clockwise +110 degrees to
counter clock wise -110 degrees. This titling head 9 consists of Tool Holder 10, which
holds the multi master cutting tool shank 11. This shank can accommodate different
kinds of cutting tool heads 13 of different forms based on the type of machining such as
rough, semi-finish and finish machining.
In the embodiment of the present invention, the Bladed Ring 5 consisting of 32
nos. of blades 6 integrally, are to 5-Axis scoop machined from a single forged blank 7.
To accommodate on the machine in a single layout extra holding plate 8 is included in
the forged blank 7. This forged blank 7 is held with the help of holding plate 8, locating
pins 14 and fixture plate 4 on to the face plate 3 of the rotary table 2. Suitable 5-Axis
CNC programs generated for multi-patch machining of the Inlet Side 13 and Outlet

Side 16 Passages to cover the entire bladed ring passages such as inlet area, outlet
area, hub, shroud, pressure side and suction sides of blades. These 5-Axis multi-patch
CNC programs are developed with different configurations of the cutting tool heads 12
covering rough, semi-finish and finish machining with Flat end mill, Bull nose, Tapered
ball nose, Tapered bull nose, Lollypop, Bulb etc... forms. By running the above CNC
programs from both inlet & outlet side passages and using the above mentioned cutting
tools the total bladed ring 5 is machined in a single layout on the 5-Axis machine with
rotary indexing table 2 & both sides tilting head 9.

WE CLAIM
1. A single layout holding method for 5-axis multi-patch scoop milling of steam
turbine stationary bladed rings from a single forging, the said method comprising;
including an extra holding plate (8) to hold a single forged blank (7) to
accommodate on the machine in a single lay out;
holding the forged blank (7) by said holding plate (8), locating pins (14) and a
fixture plate (4) on to a face plate (3) of a rotary table (2) of a 5-axis scoop milling
machine; wherein,
a CNC-program is generated for multi patch machining of inlet side (13) as well
as outlet side (16) passages to cover the entire bladed ring passages like inlet area,
outlet area, hub, shroud, pressure side and suction side of blades, with different
configurations of the cutting tool heads (12) covering rough, semi-finish, and finish
machining with flat end mill, bull nose, tapered ball nose, tapered bull nose, lollypop
forms, wherein with the said CNC program and the said cutting tools, total bladed ring
(5) is machined in a single layout on the 5-axis machine with rotary indexing table (2)
and both sides tilting head (9).