FORM 2
THE PATENT ACT 1970 (39 of 1970)
&
The Patents Rules, 2003 COMPLETE SPECIFICATION
(See Section 10, and rule 13)
1. TITLE OF INVENTION
CNC VERTICAL TURNING MACHINE WITH LIVE SPINDLE FOR MILLING
2. APPLICANT(S)
a) Name : PREMIER LIMITED
b) Nationality : INDIAN Company
c) Address : 58, NARIMAN BHAVAN,
NARIMAN POINT, MUMBAI-400 021, MAHARASHTRA, INDIA
3. PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed : -

FIELD OF INVENTION
The present invention relates in general to CNC Vertical Turning Machines for milling, and in particular to a CNC vertical turning machine with live spindle for milling which is adapted for machining of work piece of diameter up to 1600 mm with high-speed rotation of the parts to be machined, greater stability and less chatter.
BACKGROUND OF THE INVENTION
Turning machines are used to machine metal pieces to acquire desired shapes from a piece of stock. The stock is turned or rotated at a relatively high speed. One type of turning machine is known as a vertical turning machine as the stock to be machined rotates around a vertical axis while it is machined. Various other types of turning machines are also known.
Turning machines generally produce a wide variety of parts, and thus are capable of operating at a wide variety of speeds and of holding a large number of different cutting tools which can be interchanged during the machining process to produce the particular part desired. While conventional turning machines are well adapted to perform a wide variety of machining operations, there are several drawbacks with the existing turning machines. For example, conventional turning machines require a cooling lubricant to be applied to the cutting edge of the cutting tool to remove heat generated during the cutting operation. Otherwise, the heat generated from the cutting operation may cause the turned part, such as an aluminum part, to melt, and may otherwise damage the finish of the machined part. Unfortunately, coolant is expensive, leaves a residue on the finished part and on the turning machine, and may possess environmental and health hazards.
Additionally, as a typical turning machine is designed to be highly versatile, it often requires a transmission to adjust the turning speed of the stock material, a turret or

ram to house a large number of cutting tools, and various other assemblies to improve the flexibility and versatility of the machine. As a result of the complexity of the turning machines, they also are difficult and expensive to maintain and tend to wear very quickly. The primary area of wear in conventional turning machines is the drive arrangement. The drive arrangement typically includes a motor, a transmission, a belt to transfer rotational power to the spindle and chuck assembly, and a number of drive belts and pulleys. In such an arrangement, the drive components transfer rotational power through a plurality of drive belts and pulleys which are maintained under significant tension so that the drive power from the motor can be efficiently transferred to the spindle and chuck.
Unfortunately, the transmission and the brake tend to wear out significantly as do the bearings of the various rotational items, such as the pulleys, because of the significant amount of belt tension and resultant stresses on the components. Another drawback of the conventional turning machines is that the rotational speed of the stock material, and thus the speed at which the material can be machined, tend to be limited to speeds below which these machines begin to experience chatter and vibration which can harm the machine or damage the part being machined.
It is therefore desirable to provide a turning machine which could turn the part to be machined at a high speed and still not experience chatter and thus allow the parts to be machined faster.
The present invention represents an advance over machines of the prior art by providing a mechanically stiffer machine exhibiting improved dynamic characteristics. The invented machine is more reliable than the machines of the prior art.
OBJECTS OF THE INVENTION
The primary object of the invention is to overcome the drawbacks of the prior art.

Another object of the present invention is to provide a CNC vertical turning machine suitable for machining large parts of diameter up to 1600 mm at high speeds of rotation.
A further object of the present invention is to provide a vertical turning machine with low vibration and chatter.
Yet another object of the present invention is to provide a CNC vertical turning machine which incorporates a minimal number of moving parts and assemblies which help reduce its vibration characteristics.
Another object of the present invention is to provide a CNC vertical turning machine with a base having adequate mass and structural rigidity to provide significant damping to the machine to reduce harmonics and vibrations (i.e. chatter) generated by the cutting action of the machine and rotation of the drive motor.
A further object of the present invention is to provide a turning machine wherein both the axes (X and Z) drives have hardened and ground precision ball screws (6, 18) with preloaded double-nuts to ensure high running accuracy.
SUMMARY OF THE INVENTION
A CNC vertical turning machine with live spindle for milling comprises of a table base on which an AC Servo motor for rotating the machine table at high speed and a spindle assembly are mounted. The table has a plurality of jaws which are operated hydraulically. A column is connected to the table base by means of bolts. The machine also has an ATC, a moving cross rail, ram head assembly, live spindle drive, Z axis drive, X axis drive, chip conveyor, chip trolley, filtration unit and electrical control panel. The machine incorporates a minimal number of moving parts and assemblies which help reduce its vibration characteristics and make the

machine adapted to turn the work piece to be machined at a high rate with minimal vibration and chatter.
The table base is a thermo symmetric grey cast iron structure providing a stiff and rigid machine base of sufficient mass and area to provide dampening which facilitates reduction of vibrations and harmonics generated by the machine during machining operation.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The nature and scope of the present invention will be better understood from the accompanying drawings, which are by way of illustration of a preferred embodiment and not by way of any sort of limitation. In the accompanying drawings:-
Figure 1(a) illustrates the front view of the vertical turning machine according to the present invention.
Figure 1(b) is the side view of the vertical turning machine.
Figure 1(c) shows the plan of the machine.
Figure 2 illustrates the ram head assembly.
Figure 3 is a schematic representation of the live spindle drive of the vertical turning machine according to the present invention.
Figure 4 schematically illustrates the table drive of the machine.
Figure 5(a) schematically illustrates the z-axis kinematics of the vertical turning machine.

Figure 5(b) schematically represents the x-axis kinematics of the machine.
Figure 6 schematically illustrates the ATC kinematics of the machine.
DETAILED DESCRIPTION OF THE INVENTION
Having described the main features of the invention above, a more detailed and non-limiting description of a preferred embodiment will be given in the following paragraphs, with reference to the accompanying drawings.
The CNC vertical turning machine is suitable for the following machining operations:
■ Boring
■ Turning
■ Facing
■ Taper Turning and Tapping
In addition to the above, Vertical turning machine (With Live spindle) with 'C axis also performs following operations.
■ Milling
■ Slotting
■ Tapping
OD and ID Grinding
The CNC Vertical Turning Machine with live spindle disclosed in the present invention is a turret-less vertical turning machine for milling. It isillustrated in figuresl (a, b and c) to figure 6 of the accompanying drawings and comprises of:

1. Table base
2. Column
3. Table
4. AC Servo Table Motor
5. Table Gear Box
6. Pulley 1
7. Pulley 2
8. Flat Belt
9. Table lubrication Power Pack
10. Cross-rail
11. AC Servo X axis Motor
12. X Axis Ball Screw
13. Gear
14. Pinion
15. Main Hydraulic Power Pack
16. Ram Head
17. AC Servo Z axis Motor
18. Z Axis Ball Screw
19. Ram
20. Ram Housing
21. Tool Holder
22. Balancing Cylinder
23. Gear
24. Pinion
25. Hydrostatic Pump
26. Hydrostatic Power Pack
27. Elevating Gear Box
28. Elevating Motor
29. ATC
30. AC Servo ATC Motor
31. Tool Magazine Plate

32. Gear Box
33. Pinion
34. Gear
35. Live Spindle
36. Live Spindle Motor
37. 2 Speed Gear Box
38. Helical Gear
39. Helical Gear
40. Helical Gear
41. Chip Conveyor
42. Chip Trolley
43. Paper Band Filtration Unit .
44. Cladding
45. Oil Cooling Unit
46. Control Panel
47. Voltage Stabilizer
48. Voltage Transformer
The preferred but non-limiting embodiment of the CNC vertical turning machine with live spindle for milling according to the present invention is best represented in figures 1(a), 1(b) and 1(c).
The main components of the machine area rotary table for rotating a work piece; one column; a simply supported moving cross rail supported on column; one ram suspended from the ram head and movable vertically along the guide ways of the ram head and one automatic tool changer unit.
The machine is designed and adapted for machining of work pieces of diameter up to 1600 mm with high-speed rotation suitable for the manufacture of comparatively large sized parts with the usual requirements of high accuracy of finish and maximum rate of production. The vertical turning machine incorporates a minimal number of moving parts and assemblies which help reduce its vibration

characteristics and hence the machine is adapted to turn the work piece to be machined at a high rate with minimal vibration and chatter. The machine has a table base (1) manufactured from Grey Cast Iron grade as per IS to which an AC Servo motor (4) for rotating table (3), best seen in figure 4,and a spindle assembly are mounted. All the sliding surfaces of the rotating table are ground for accurate turning and long service. The table has a plurality of hydraulic jaws for clamping the stock to be machined. The jaws are made of alloy steel which ensures better gripping at cutting loads. Their stable gripping powers, even in the higher speed ranges, make them ideal for CNC application. A strong hydraulic braking system is provided which prevents accidents even during power failure.
Column (2) is fixed on the base by means of bolts. The base (1) is designed with adequate mass and structural rigidity to provide significant damping to the machine to reduce harmonics and vibrations (i.e. chatter) generated by the cutting action of the machine and rotation of the drive motor.
As best shown in figure 1(c), the main hydraulic power pack (15) is used for clamping the tool holder, for actuating the ram balancing cylinder, for clamping and positioning the cross rail and for actuating the chip guard and ATC door. Table lubrication power pack (9) is used for lubricating the table gear box and hydrostatic power pack (26) is used for lubricating the hydrostatic guide ways on which the ram moves.
An automatic lubrication system is used in the machine, which provides lubrication in pressurized state to all sliding elements like cross rail up-down movement. Recirculation type oil lubrication is provided for spindle assembly.
Oil cooling unit is used to cool the oil supply given to the main hydraulic power pack.
Chip conveyor (41) is designed for maximum chip carrying capacity. Slat or scraper type chip conveyor is provided for carrying the chips from the machine interior to the

chip trolley (42). Both the chip conveyor and trolley are place on ground in front of table base.
A coolant tank of adequate capacity is provided along with rotary drum type filtration unit (43) for recirculation of coolant.
A conventional CNC controller is used. Control panel (46) is mounted on left side of machine. Swiveling type pendant box is mounted in front of the machine at one side of the operator, which is designed on the basis of Ergonomics.
Voltage stabilizer (47) is used to stabilize the voltage fluctuations of the incoming power.
An isolation transformer (48) is used to isolate the power supply to the machine from the main power supply.
Figure 2 illustrates the ram head assembly. A tool holder (21) is located and clamped in the ram (19). Clamping of cutting tool is done with the help of disc spring and clamping piston. Balancing cylinder (22) gives support to ram (19). The ram is located in a ram housing (20) with help of hydrostatic guide with wedges. Hydrostatic pump (25) supplies oil to distributor from hydrostatic power pack (26) for lubricating the wedges for smoothening the movement of ram (19). Coolant is delivered at the cutting point through adjustable coolant nozzles in ball screw (18) by Z axis servo motor (17), best shown in figure 5(a).
Figure 3 schematically represents the live spindle drive. The main spindle (35) is driven by spindle motor (36) through a two-speed gear box (37) which provides spindle drive in two different speed ranges. The machine with live spindle ('C axis) offers drilling, tapping, milling and slotting operations in addition to turning, boring and facing.

Figure 4 is a schematic illustration of the table drive. The rotary movement of the table and hence the work piece is achieved by AC servo table motor (4) through flat belt (8) and pulley mechanism (6,7).
Figure 5 (a) illustrates schematically the drive mechanism for Z axis. An AC servomotor (17) is coupled through gear transmission (23, 24) to precision ball screw (18). It is this gear drive to ball screw that results in high rapid travel for Z axis.
Figure 5 (b) illustrates schematically the drive mechanism for X axis. An AC servomotor (11) is coupled through gear transmission (13, 14) to a precision ball screw (12). It is this gear drive to ball screw which results in high rapid travel for X
axis.
Figure 6 illustrates the kinematics of the Automatic Tool Changer (ATC) (29). The drive to the ATC is transmitted through gear-and-pinion arrangement (33, 34) from drive motor (30), which can be a conventional motor. ATC (29) for ram consists of a horizontal disc type magazine plate (31) with tool pockets for boring, turning, milling and drilling tools and special adapters for mounting rotary tools. The magazine plate is mounted on a separate column located on the right side of the machine.
DISTINGUISHING FEATURES OF THE INVENTION
l.Ball Screws (6,18)-Both the axes drives are driven by AC servomotors through a gear pair. Additionally, the servomotor for the z axis (17) has a built in holding brake to prevent the axis drive from moving downwards in power failure condition.
2.Base (1) is of sufficient mass and area to provide dampening which facilitates reduction of vibrations and harmonics generated by the machine during machining operation. The Table Base is a thermo symmetric cast structure providing a stiff and

rigid machine base. The table drive gear box (5) is integral to it. The table base also acts as a sump for the table bearing/gear box lubrication system.
3. Column (2) is a cast structure with integral ground guide ways. It is bolted on the top of the base at the rear. The column is of thermo symmetric design. It carriesthe cross rail with cross rail head (ram head). The cross rail elevating drive/gear boxes are mounted on the column top.
4.Table Bearings: A preloaded anti-friction bearing system for high axial and radial rigidity and accuracy is provided. It consists of a combination of a thrust bearing to take the axial forces and a precision angular contact ball bearing to take the radial forces.
5.Main Drives: The table is driven by AC table motor (4) through pulleys (6, 7) and flat belt (8). The table motor (4) is mounted vertically at the rear of the table base. The live spindle is operated by spindle motor (36) through 2-speed gear box (37) connected to the motor. The speed is infinitely variable between minimum and maximum values.
6.Automatic tool changer (29):It consists of a horizontal disc type magazine (31) with coded tool pockets and power clamping in ram for turning tools, clamping of tool holders in symmetrical dovetail location and positive locking in cutting force direction. The magazine is mounted on a separate fabricated column located on the right side of the machine. Tools are locked in magazine pockets by means of two spring loaded ball tipped grub screws for lightly locking the tool holders.
The present invention has been described with reference to some drawings and a preferred embodiment purely for the sake of understanding and not by way of any limitation and the present invention includes all legitimate developments within the scope of what has been described herein before and claimed in the appended claims.

WE CLAIM:
1. A CNC vertical turning machine with live spindle for milling comprises of table base (1) on which an AC Servo motor (4) for rotating table (3) having a plurality of jaws and a spindle assembly are mounted, column (2) connected to said table base by means of bolts, ATC (29), cross rail (10), ram head assembly, live spindle drive, Z axis drive, X axis drive, chip conveyor (41), chip trolley (42), filtration unit (43), and control panel(46), wherein the machine incorporates a minimal number of moving parts and assemblies which help reduce its vibration characteristics and makes the machine adapted to turn the work piece to be machined at a high rate with minimal vibration and chatter.
2. The CNC vertical turning machine with live spindle as claimed in claim 1, wherein said table base (1) is a thermo symmetric grey cast iron structure providing a stiff and rigid machine base of sufficient mass and area to provide dampening which facilitates reduction of vibrations and harmonics generated by the machine during machining operation.
3. The CNC vertical turning machine with live spindle as claimed in claims 1 and 2, wherein said table base (1) also acts as a sump for the table bearing/gear box lubrication system and said table drive gear box (5) is integral to said table base.
4. The CNC vertical turning machine with live spindle as claimed in claim 1, wherein said column (2) is a cast structure of thermo symmetric design with integral ground guide ways which are bolted on the top of the base at the rear, carries said cross rail (10) with cross ram head and has the cross rail elevating drive/gear boxes mounted on its top.

5. The CNC vertical turning machine with live spindle as claimed in claim 1, wherein said ram head assembly comprises of a ram (19) located in a ram housing (20) with help of hydrostatic guide with wedges, a tool holder (21) located and clamped in the ram (19), balancing cylinder (22) which gives support to ram (19), wherein clamping of cutting tool is done with the help of disc spring and clamping piston, hydrostatic pump (25), Z axis drive motor (17) and Z axis ball screw (18).
6. The CNC vertical turning machine with live spindle as claimed in claim 1, wherein said live spindle drive comprises of main spindle (35) driven by spindle motor (36) through a two-speed gear box (37) which provides spindle drive in two different speed ranges.
7. The CNC vertical turning machine with live spindle as claimed in claim 1, wherein the rotary movement of said table (1) and hence the work piece is achieved by AC servo table motor (4) through flat belt (8) and pulley mechanism (6, 7).
8. The CNC vertical turning machine with live spindle as claimed in claim 1, wherein said Z axis drive comprises of an AC servomotor (17) coupled through gear transmission (23, 24) to precision ball screw (18) resulting in high rapid travel for Z axis.
9. The CNC vertical turning machine with live spindle as claimed in claim 1, wherein said X axis drive comprises of an AC servomotor (11) coupled through gear transmission (13,14) to a precision ball screw (12) resulting in high rapid travel for X axis.
10. The CNC vertical turning machine with live spindle as claimed in claim 1, wherein said ATC (29) has a horizontal disc type magazine (31) with coded tool pockets and power clamping in ram for turning tools, clamping of tool

holders in symmetrical dovetail location and positive locking in cutting force direction, the magazine being mounted on a separate fabricated column located on the right side of the machine.