FIELD OF INVENTION
The present invention relates to an arrangement for facial mounting of
square shank tools, adapted on a tool post of a CNC machine for taking LH and RH
facial cuts on a component loaded on the machine.
BACKGROUND OF THE INVENTION
CNC indicating Stand, installed in Turbine Shop, is used for following
operations demanding high accuracies & surface finish:
♦ Turning Operations on Bladed Turbine Rotor, including machining (diameters,
faces, grooves/profiles & sealing fins/grooves) of shrouds of blades.
♦ Grinding of Journal Dia/Faces, Flange Faces.
♦ Blading Operations i.e. Assembly/Fitting of Large Size Blades & Seal Strips on
Rotor.
♦ Repair Work on Used Rotors received from site including machining out the
seal strips.
The machine has one headstock, one carriage unit and two hydrostatic
steady units. All these units can be shifted and clamped as per requirement on its
bed made of bed plates having T-slots.
Its carriage has one turning tool post having two axes movements with
provision to mount VDI cassettes radially for clamping of square shank cutting tools
in radial direction only. VDI cassettes is a standard tool holder used in a CNC
machine.

In bladed rotors, generally, tools at facial mounting are also required
for taking facial cuts on both LH & RH sides, as per requirement. As and when
required, these facial cuts were taken either with some weak temporary
arrangement of clamping of tool at same tool post or this work was getting done on
other conventional indicating Stand or Lathe. Both of these situations were resulting
in deterioration of achievable quality parameters of machined surfaces or substantial
delay in completion of required machining. Both the problems were affecting our
production schedules adversely. When bladed rotor is required to be machined on
the indicating Stand, it is at very critical stage and very close to its dispatch. Any
problem at this stage has serious repercussions. Trouble free completion of all the
foreseen activities in single go on this machine is of paramount importance.
There was no provision for facial mounting of tools on the machine's tool post.
There is no sufficient space available to clamp conventional tool holders for facial
clamping. The plate's thickness is only 60mm. So it was not possible to take
accurate machining cuts required to be taken on bladed rotors with facial mounting
of tools. This requires a rigid clamping of VDI cassette of width 115 mm in facial
direction on a 60 mm width plate without interfering with radial holder mounted on
side of plate. It needs to be ensured that there is no collision with any part of rotor
while using this holder for machining.
OBJECTS OF THE INVENTION
Therefore, it is an object of the invention to propose an arrangement
for facial mounting of square shank tools adapted on tool post of the CNC machine
for taking LH and RH facial cuts which is capable of being assembled on existing tool
post without any interference with radial holder mounted on side of the plate of the
tool post.

Another object of the invention is to propose an arrangement for facial
mounting of square shank tools adapted on tool post of the CNC machine for taking
LH and RH facial cuts which ensures machining without any collision with any part of
rotor.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Fig.l - Shows the arrangement for adapting facial mounting of VDI cassette for
clamping of square shank tools according to the invention.
Fig. 2 - Shows the base plate of the arrangement according to the invention.
Fig. 3 - Shows the clamp to hold the cassette for clamping of square shank tools in
accordance with the invention.
Fig. 4 - Shows the guided clamp on the other side of the base plate in accordance
with the invention.
Fig. 5 - Shows the VDI cassette assembled in between the clamps according to the
invention.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE
INVENTION
The present invention has three parts which have been assembled to
form required arrangement. Each part has been designed and manufactured to suit
limited space and ensuring rigidity. The parts are (i) Base plate (1) (ii) clamp (2) (iii)
Guided clamp (3). The clamps (2, 3) are assembled by screw M10 X 35 (4) and M5

X 35 (5) on the base plate (1). The width of the base plate (1) matches with the
width of the plate of tool post of the CNC machine. It has 4 holes (11,12) of 13 mm
dia to fix it rigidly on the plate of the Tool post with standard screws. The plate (1)
has a slot (6) along its length to accommodate locking key of VDI cassette (14) to
be clamped on it. The arrangement is made in such a manner that the same VDI
cassette (14) can be mounted on the tool holding arrangement and the new
invented mounting arrangement is made without compromising rigidity of tool post.
VDI cassette (14) has tapered surfaces on its both ends. Suitable clamps (2, 3) and
wedges have been manufactured to perfectly match these tapered surfaces to avoid
vibrations during machining. A guided clamp (3) having a tapered surface (8) is
fixed in a slide-fit keyway (13) made on the base plate (1) and clamped (3) on one
side of the base plate with the help of three screws (5) screwed on three threaded
holes (9). Other end has removable clamp having matching tapered surface (7) with
three threaded holes (10) for perfect clamping. The taper surfaces (7, 8) of the
clamps (2, 3) matches with that of the VDI cassette (14). The slot (13) on the base
plate (1) is made all along the width for allowing the guide clamp (3) to move width-
wise. The base plate is made of mild steel and then hardened and ground. The
clamps (2, 3) are also made of mild steel and then hardened and ground. The slots
6 and 13 are grinded to the required dimension.

WE CLAIM
1. An arrangement for facial mounting of square shank tools adapted on tool
post of a CNC machine for taking LH and RH facial cuts on a component
loaded on the machine, the said arrangement comprising;
making a slot (13) along the width of a base plate (1);
fixing the base plate (1) on the plate of tool post of the said machine;
fixing a removable clamp (2) on one side of the base plate (1);
fixing a guided clamp (3) in the slot (13) of the base plate;
making a slot (6) on the base plate along its length to accommodate the
locking key of VDI cassette (14); wherein
the taper surfaces of the clamps (2, 3) disposed on the base plate (1)
perfectly match the taper surfaces of the VDI cassette (14) fixed in the
key slot (6) of the base plate (1).
2. A method of arranging facial mounting of square shank tools as claimed in
claim 1, wherein clamp (2) is fixed by M10 X 35 screw and clamp (3) is
fixed by M5 X 35 screws.
3. A method of arranging facial mounting of square shank tools as claimed in
claim 1, wherein the length, width and thickness of the base plate (1) are
200mm, 60mm, 35mm (max.) respectively.
4. A method of arranging facial mounting of square shank tools as claimed in
claim 1, wherein the length, width and height of the removable clamp (2)
are 60mm, 14mm (parallel part), 13mm.
5. A method of arranging facial mounting of square shank tools as claimed in
claim 1, wherein, the length, width and height of the guided clamp (3) are

60mm, 30mm (parallel part), 15+4.5mm.
6. A method of arranging facial mounting of square shank tools as claimed in
claim 1, wherein, the length, width and depth of the slot (6) are 65mm,
25mm, 10mm.
7. A method of arranging facial mounting of square shank tools as claimed in
claim 1, wherein, the base plate (1) and the clamps (2, 3) are made of
mild steel material and then hardened and ground.

ABSTRACT

The invention relates to development of an arrangement for facial
mounting of square shank tools adapted on a tool post of a CNC machine for taking
LH and RH facial cuts comprising fixing a base plate (1) on the plate of the tool post
of the CNC machine and then fixing a removable clamp (2) in one side of the plate
(1) when a slot (13) is made along the width of the base plate to fix a guided clamp
(3) on it. Both the clamps (2, 3) are being made tapered on the front face. Another
slot (6) is machined to accommodate the VDI cassette (14) which is fixed in the slot
(6). The taper surface of the VDI cassette matches perfectly with the taper surfaces
of the clamps.