FORM - 2
THE PATENTS ACT, 1970
(39 OF 1970)
COMPLETE SPECIFICATION.
(Section 10; Rule 13)
Title: - Double Column NC Controlled with Electric servo Ball Screw
Driven cutting head feeding and bar indexing band saw Machine.
Name, Nationality & Address of the Applicant
ITL INDUSTRIES LIMITED (Incorporated company under Indian company Act. 1956) 111, Sector - " B ", Sanwer Road , Indore,452015(M.P.).lndia
The following specification particularly describes the nature of this invention and the manner in which it is performed:-

Filed of the Invention:-
To overcome limitations in above explained conventional machines by converting a hydraulic cylinder operated cutting feed and indexing operation to an electric servo and ball screw driven arrangement along with an intelligent PLC ( Programmable Logic Controller) (5).
1. Cutting Head Feed:-
The downward motion of cutting arm is programmed in such a way that depending upon the material composition and size of the bar , PLC ( Programmable Logic Controller ) (5) screen display the type of blade required and its running speed in meters per minute to achieve optimum productivity and tool life with the help of electric servo. It is possible to define load per tooth in relation to a blade speed and its pitch. In case of round shape bars the down cutting feed is varying depending upon the contact length with the bar. when blade enters, its feed is very high and reduces gradually up to the center and then automatically again increases as the blade contact length decreases, this way the productivity is enhanced by 20 - 30%. In case of square or rectangular bar the feed rate remains constant as the blade contact length does not change . at the time of contact with the material blade speed and feed are automatically reduces as per programmed depending upon the material composition and manufacturing process, this feature saves blade damage from sudden jerk, cutting arm upward motion is rapid to minimize overall production cycle time.
2. Bar Indexing to Obtain Desired Length Cut Pieces:-
An electric servo (4) with ball screw (1) is moving the shuttle to die definite distance with ± 50 micron accuracy after each cut is complete.

It is possible to program variety lengths and number of pieces required from the same bar, which automatically perform and cut the pieces with high degree of accuracy without a risk of rejection. Programs can be saved in memory and can be used as and when required just by putting the programs No. in PLC , (5) desired cut pieces can be obtained.
Back Ground and Prior invention :-
1. High speed metal cutting band saw machines with twin column are in use for last 2 1/2 decades using HSS bimetal band saw blades . these machines are having double column construction wherein the cutting head is guided in two vertical columns. The cutting head is provided with phosphorus bronze bushes which slides on vertical columns which are hardened ground and hard chrome plated or modular construction linear motion guide bearing rail pair mounted on two vertical steel columns .
2. HSS bimetal band saw blades perform very well, cut faster, taper free cuts when blade is stretched above 35000 PSI force to obtain very strong beam. when this force is applied on to the blade through hydraulic cylinder or manually by screw, blade forms a strong beam which has very high strength to cut the material without deflection if proper depth of cut is provided while lowering the cutting head into the material, as per the research report generally 4 to 6 micron depth of cut per tooth gives excellent performance in cutting with highest degree of productivity and best tool performance in terms of cutting in sq meters till it gets blunt.
3. In conventional band saw machines , lowering of cutting arm in done by draining the oil from vertical cylinder under definite pressure to obtain lowering velocity of the cutting head in mm/min. This lowering rate is decided based on material machinability which is being cut and the area of cross section to be cut. based on rough estimates of cutting rate for the given material e.g. medium carbon steel having carbon 0.35 % can be cut at

60 sq cm / min. if the bar is of 100mm sq , its area is calculated as 100 sq cm and it should be cut in 1.66 min. accordingly, flow control valve is set at lowering rate of 100/1.66 = 60 mm/min. graduation on flow control valve scale are very coarse and it is very difficult to establish the cutting rate, also, with the change in temperature and pressure feed rate changes causing fast or slow cutting than the set values may hamper the productivity or increase the tool wear at higher depth of cut.
4. Material cut on these band saw machines have varied hardness because of their composition and heat treatment . many times due to improper heat treatment, post manufacturing process causes uneven hardness in the material, band saw machines are operated through hydraulic cylinders for up down motion of the cutting arm. when cutting resistance of the material is more due to its property or the length of the cut does not allow blade to penetrate in the material and whereas the down feed remain constant at a definite feed rate, to avoid crooked cutting or failing of the blade, it is necessary to regulate the feed automatically to avoid poor cutting and damage to the blade.
5. In fully automatic band saw machine, cutting of square or round bars with high degree of precision in length is difficult because of indexing accuracy of the bar with the hydraulically operated shuttle system, such arrangement is working between two limit switches or proximity switches but both have some limitation on exact position for stopping the cylinder . since length accuracy is required within +/- 0.05 mm it becomes difficult to obtain such precise lengths.
6. Conventional automatic band saw machines are designed on the shuttle system wherein after every Indexing main vise clamps the bar, shuttle vise opens & return to the set cut length position and clamps the bar again, after cutting of the bar, main vise opens and shuttle vise index the bar to pre set length and again comes back to its home position. In this

construction, lot of time is wasted in frequent opening, closing and indexing of the shuttle, also, the length variation is more in cut pieces.
Description of invention :-
The Present invention is divide in two part
1. To overcome limitation of controlling depth of cut with in the range of 4 micron to 8 micron per tooth , AC (alternative current) servo motor (4) with ball screw (1) and a high ratio reduction gear box is provided . AC Servo motor is controlled with an intelligent PLC and HMI ( human machine interface ) (5) . Depending up on the material machinability, diameter of the bar, blade teeth configuration, program is fed into the PLC (5) which automatically work out the blade cutting speed in met/min and depth of cut such that optimum cutting rate is obtained with the highest tool life for the particular material, also , correct parameters of cutting offers taper free cuts and good surface finish, since, servo motor does not have any change in its performance with the change in room temperature gives consistent feed rate and consistent tool life. Servo motors are very sensible in sensing the change in torue. This feature helps automatic regulation of feed rate in case material hardness changes due to improper heat treatment or poor production method. This way tool life can be saved without human involvement.
D- BAR INDEXING THRU AC SERVO MOTOR:
1. In automatic bandsaw machine thousands of pieces are cut as per the pre programmed lengths, to get very precise length of cut say with in +/-0.05 mm, A C Servo motor (4) is used with ball screw arrangement to index the bar for cutting (1) . cold forging application demands weight variation with in +/- 1 gram by weight, as such accurate lengths can be achieved by using servo motors, tool wear compensation is possible which is an added advantage to adjust automatically without human involvement, machine can

run without operator whole night. Such reliability is possible with the introduction of new feature.
PLC program (5) and shuttle stroke has been designed in such a way that small cut lengths can be obtained at a higher production rate without return stroke of the shuttle up to the cut length distance after every cut . In such construction, depending upon the programmed cut length, the shuttle moves forward and stops after indexing the set length of the material. When the material is cut, again shuttle moves forward to set length distance and piece is cut, this way several pieces are cut. This operation is continuously done till the shuttle reaches to main vise. From this point, shuttle vise comes home position rapidly, in this concept, length variation is minimum and efficiency increases by reducing the cycle time.
other part of the invention is bar indexing to obtain desired length cut pieces, an electric servo with ball screw is moving the shuttle ( 3) to the definite distance with ± 50 micron accuracy after each cut is complete.
It is possible to program variety lengths and number of pieces required from the same bar, which automatically perform and cut the pieces with high degree of accuracy without a risk of rejection, programs can be saved in memory and can be used as and when required just by putting the programs No. in PLC , desired cut pieces can be obtained.
Technical Specification for model: LMGNC Models
Cutting capacity - Round 100 to 3000 mm various models
Square/ Rectangular 100 to 3000 mm various models
Cutting speed - 20 to 100 MPM
Blade size - 3 760 to 20,000 mm
Saw Motor capacity - 5 to 50 HP Coolant motor capacity - 0.24HP.63LPM

Coolant Reservoir -100 Ltr. Hydraulic Motor - 2HP Hydraulic Reservoir - 40 Ltr. Shuttle stroke - 400 mm (without bundle)

CLAIMS -We claim for
1. A Head feeding machine comprising of
Numeric controlled bar indexing thru ball screw (1) and A C Servo motor (4) for shuttle movement (3) to precisely position the bar to be cut in semi auto & auto mode in double column band saw machines & NC Controlled cutting head down and up return movement thru ball screw (1) and A C servomotor (or very precise feed in terms of load per tooth depending upon material machrnability as programmed .
2. A Machine consisting of NC controlled bar indexing thru ball screw (1) & A C servomotor (4) for shuttle movement (3) to precisely position the bar to be cut in semi auto and auto mode in double column band saw machines .
3. A Machine consisting of NC Controlled cutting head (2) down and up return movement thru ball screw and A C Servomotor (4) for very precise feed in terms of load per tooth depending upon material machinability as programmed .