FIELD OF INVENTION
The present invention relates to a device for setting the desired length and
checking the taper present in the rectangular cross-sectional blank length during
face milling operation for manufacturing turbine blades.
BACKGROUND OF INVENTION
In New Blade Shop, finished blades are machined from rectangular cross
sectional blank in all 5-axis machines. The blanks are held from centre to centre
in 5-axis machines while blade machining. So, face milling operation and
centering operation is carried out in both sides of the blanks in HMC machines.
These blanks are then loaded in 5-axis machines for complete blade machining.
While carrying out the face milling operations, it is essential to confirm the length
(as per drawing) of the blank every time in every blank otherwise it may result
center shift & chances of accident in all 5-axis machines.
During the preparation of blank length, blanks are cut in band saw machines and
the cutting operation imparts taper in the blank length.
When we load blanks on 5 axis machines then center axis of blades should be
matched with the center axis of blanks. The center axis of blanks affects if blank
is taper & taper blank disturb the center axis of blade. Due to this shroud side of

the blades shifts & all dimensions of shroud side deviates. Sometimes material
has been left on blades on shroud side either pressure side or suction side & due
to this finished blade are rejected on machines. Sometimes in roughing operation
of blades, cutter body wear out on blanks due to uneven material on both sides
of blanks & that occurs due to taper in blank.
Therefore a special type device is developed to set taper in blank because the
length of the blank and to check taper in blank if exist as to carry out the facing
operation in HMC machine.
OBJECTS OF THE INVENTION
Therefore, it is an object of the invention to propose a device for setting the
desired length and checking the taper present in the rectangular cross-sectional
blank length during face milling operation for manufacturing turbine blades
which is capable of setting the required length of rectangular cross sectional
blanks while carrying out the face milling operation.
Another object of the invention is to propose a device for setting the desired
length and checking the taper present in the rectangular cross-sectional blank
length during face milling operation for manufacturing turbine blades which is
able to check the taper present in the blanks imparted during cutting of the same
in band saw machines.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
Fig.l - Shows the device assembly.
Fig.lA - Shows the device assembly with dismantled machine fixture.
Fig.2 - Shows a base clamp which is clamped to the base of the machine
fixture.
Fig.3 - Shows a special designed slotted part along which a rectangular
unit swivels.
Fig.4 - Shows a vertical column (9) which is fixed to the machine base
vertically.
Fig.5 - Shows the moveable arm which swivels along part-2
Fig.6 - Shows the detailed view of the assembly.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE
INVENTION
The new device (C) consists of a base (1) measured 226 mm X 60 mm X 20 mm
having a base where two threaded holes of M8 (13) are present and showing in
fig-2. The unit having a slotted portion (12) at the bottom also shown in fig-2.
The base (1) is fixed to the machine base by means of a T- headed nut and a
hexagonal headed bolt(unit 6).

The unit (2) is a specially designed part which is fitted with part 1 with the help
of bolt shown by unit (6). The bolt (6) fixes unit (2) with base (1) and also fixer
base (1) to the machine fixture. It has a recess which holds the head of the bolt
(6). It has a general hole where unit 5 is clamped by means of nut and bolt of
M12 shown by unit (3 & 4). The unit 5 swivels along unit 2. The unit 2 can slide
in slotted portion of unit (1).
The unit 5 is a rectangular unit having rounded ends and round ends are
provided for machine operator safety as sharp ends may causes accident to the
operators. This is the part that helps to set the length. It swivels around unit 2
and it has a threaded hole of M8 where a bolt (7) is attached. The bolt acts as a
handle to check by swiveling the unit 5. The surface of the unit 5 touches the
face of the rectangular cross sectional blank (8) while the length of the blank (8)
is set by sliding unit 5 with the help of unit 2 in slotted portion of unit 1.
Unit (9) is a vertical column which is attached to unit 1 by means of two
threaded bolts in the threaded holes (M8) and is fixed to the machine fixture
(11) vertically with the help of bolt and T-nuts in the T-slotted portion (10) of the
vertical column of the fixture. The recess holds the head of the bolt.
Part 8 is the rectangular cross sectional blank which is clamped in the machine
fixture (11) so that clear view of device may shown. The length of the blank
required is checked with the help of the unit (5) and clamped accordingly. After

setting the length, the blank is clamped with the machine fixture and face milling
operation is carried out to make center and clean the face of blank.
All the 4 units (except the standard nuts and the bolts) are made of EN-24
material. All are hardened and ground.
PROCESS:
In the old method when a blank piece is put on machine fixture, it firstly checked
by vernier scale at a fixed value of 40-50 mm so that the face milling cutter may
not strike to the machine fixture. This work of setting the blank take at least 5-8
minutes and as this work is manual there may be chances of error and if there is
taper in blank, the blank may not sit properly. The blank taper is not clean and
unclean material left. Due to this rework and rejection is there.
By making this device need of vernier scale is once and after setting the process
is continuously used and setting of blank on machine fixture is fast. In this device
we have sliding unit to set the blank shown by unit 2 and it can slide with the
help of unit 5.The unit 5 is also help to check the taper on the clean face of
blank after machining. This will decrease the chance of rework and require
length of blank may be achieved. If there is taper, face of unit (5) will not match
with the face of the blank. Once unit 5 and 2 are fixed for a certain length of the
blank and for the taper of blank, the length and taper of subsequent blanks can
be easily ascertained. After cutting in the band saw, an allowance of 55 mm

length wise is given. This blank (8) is put on the machine fixture keeping 45-50
mm outside the fixture which is checked by the vernier. Item 5 is brought near
the blank to check the taper on the face of the blank. Then milling cutter cuts
the blank with cutter being perpendicular to the blank and after the facing
operation, centering operation is done when the unit 5 is swiveled to a position
when the milling cutters and centering tool gets approach to the job to machine.
Unit 5 is kept in a position for checking subsequent blanks from Band saw
machine and the whole operation is repeated.

WE CLAIM
1. A device (C) for setting the desired length and checking the taper present in
the rectangular cross-sectional blank length comprising;
a base (1) having two threaded holes (13) at the left extreme of the said
base;
a vertical column unit (9) fixed to unit (1) through bolts in threaded holes
(13) and fixed to the machine fixture (11) by bolt and nut bolted in the T-
slotted position (10) of the vertical column of the fixture an unit (2) fixed to
the base (1) with bolt (6) an unit 5 fixed to the unit (2) with nut and bolt (3,
4); Characterized in that unit 5 is disposed for checking the length of the
blank after Band saw machine and checking the taper of the said blank for
allowing the face milling cutter to machine the face for preparing the required
blank length without having taper and the centering tool to machine the
center on the correct face wherein unit 5 is swiveled around for making
provision of the approach of the cutter.
2. A device as claimed in claim 1, wherein all the units (1, 2, 5, 9) are made of
EN-24 steel, hardened and ground.