BHEL Training PPT

1. Bharat Heavy Electricals Limited
Shyamveer Singh

2. Computer Numeric Control Machines &Computer Numeric Control Machines & Programmable Logic
Controller

3. History
Embarking upon the 50th Golden Year of its journey of
engineering excellence, BHEL is an integrated power plant
equipment manufacturer and one of the largest engineering
and manufacturing company of its kind in India engaged in the
design, engineering, manufacture, construction, testing,
commissioning and servicing of a wide range of products and
services for the core sectors of the economy, viz. Power,
Transmission, Industry, Transportation (Railway), Renewable
Energy, Oil & Gas and Defence with over 180 products
offerings to meet the needs of these sectors. Establishment of
BHEL in 1964 was a breakthrough for upsurge in India's
Heavy Electrical Equipment industry. Consistent performance
in a highly competitive environment enabled BHEL attain the
coveted 'Maharatna' status in 2013.

4. INTRODUCTION
BHEL as a part of Pt. Jawaharlal Nehru's vision was bestowed
with the onus to make the country self reliant in manufacturing
of heavy electrical equipment. This dream has been more than
realised and the contribution in nation building endeavour is
going to continue likewise. Today, with 20,000 MW per
annum capacity for power plant equipment manufacturing,
BHEL's mammoth size of operations is evident from its
widespread network of 17 Manufacturing Units, two Repair
Units, four Regional Offices, eight Service Centres, eight
Overseas Offices, six Joint Ventures, fifteen Regional
Marketing Centres and current project execution at more than
150 project sites across India and abroad.

5. INTRODUCTION
The total installed capacity base of BHEL supplied equipment
138 GW in India speaks volumes about the contribution made
by BHEL to Indian power sector. BHEL's 57% share in India's
total installed capacity and 65% share in the country's total
generation from thermal utility sets (coal based) as of March
31, 2014 stand testimony to this. The company has been
earning profits continuously since 1971-72 and paying
dividends since 1976-77 which is a reflection of company's
commendable performance throughout.

6. Reserch and Development
During the year 2012-13, BHEL has invested about The R&D
expenditure of the company for the year was Rs. 1114 Crore
which was 2.76% of the turnover as against 2.49% for the
previous year. This also includes the expenditure incurred on
R&D efforts gone into major modifications/ improvements in
products/designs against customer requirements which are not
covered in R&D projects. 434 patents and copyrights were
filed during the year 2013-14, enhancing the company's
intellectual capital to 2,589, which are in productive use.
Turnover from in house developed products amounted to Rs.
8110 Crore which is 20 % of the company Turnover.

7. R & D Hyderabad
1.Simulators
2.Computational Fluid Dynamics
3.Permanent Magnet Machines
4.Surface Engineering
5.Intelligent Machines and Robotics
6.Machine Dynamics
7.Compressors & Pumps
8.Nano-technology
9.UHV Laboratory
10.Advanced Transmission Systems

8. Electronics Division Bangalore
1.Power Electronics and IGBT & Controller Technology
2.Control & Instrumentation

9. Computer Numeric Control MachinesComputer Numeric Control Machines
Introduction:-
US Air Force commissioned MIT to develop the first numericallyUS Air Force commissioned MIT to develop the first numerically
controlled machine in 1949. It was demonstrated in 1952. At 1970-1972controlled machine in 1949. It was demonstrated in 1952. At 1970-1972
first Computer Numeric Control machines were developed.Today,first Computer Numeric Control machines were developed.Today,
computer numerical control (CNC) machines are found almost everywhere,computer numerical control (CNC) machines are found almost everywhere,
from small job shops in rural communities to companies in large urbanfrom small job shops in rural communities to companies in large urban
areas.areas.
What is CNC ?What is CNC ?
In CNC (Computer Numerical Control), the instructions are stored as aIn CNC (Computer Numerical Control), the instructions are stored as a
program in a micro-computer attached to the machine. The computer willprogram in a micro-computer attached to the machine. The computer will
also handle much of the control logic of the machine, making it morealso handle much of the control logic of the machine, making it more
adaptable than earlier hard-wired controllers.adaptable than earlier hard-wired controllers.

10. Conventional vs. CNC machineConventional vs. CNC machine

11. Conventional vs. CNC machineConventional vs. CNC machine

12. CNC Machine
CNC TURNING:-CNC TURNING:-

13. CNC MILLINGCNC MILLING

14. CNC LASER CUTTINGCNC LASER CUTTING

15. CNC SYSTEM ELEMENTSCNC SYSTEM ELEMENTS
A typical CNC system consists of the following six elementsA typical CNC system consists of the following six elements
• Part programPart program
• Program input deviceProgram input device
• Machine control unitMachine control unit
• Drive systemDrive system
• Machine toolMachine tool
• Feedback systemFeedback system

16. CNC SYSTEM ELEMENTSCNC SYSTEM ELEMENTS

17. PART PROGRAMPART PROGRAM
A part program is a series of coded instructions required toA part program is a series of coded instructions required to
produce a part. It controls the movement of the machine toolproduce a part. It controls the movement of the machine tool
and the on/off control of auxiliary functions such as spindleand the on/off control of auxiliary functions such as spindle
rotation and coolant. The coded instructions are composed ofrotation and coolant. The coded instructions are composed of
letters, numbers and symbols and are arranged in a format ofletters, numbers and symbols and are arranged in a format of
functional blocks as in the following example.functional blocks as in the following example.
N10 G01 X5.0 Y2.5 F15.0N10 G01 X5.0 Y2.5 F15.0
| | | | || | | | |
| | | | Feed rate (15 in/min)| | | | Feed rate (15 in/min)
| | | Y-coordinate (2.5")| | | Y-coordinate (2.5")
| | X-coordinate (5.0")| | X-coordinate (5.0")
| Linear interpolation mode| Linear interpolation mode
Sequence numberSequence number

18. CNC Commands:-CNC Commands:-
1. Modal commands:-1. Modal commands:-
Commands issued in the NC program that will stay in effect until it is changedCommands issued in the NC program that will stay in effect until it is changed
by some other command, like, feed rate selection, coolant selection, etc.by some other command, like, feed rate selection, coolant selection, etc.
2. Nonmodal commands:-2. Nonmodal commands:-
Commands that are effective only when issued and whose effects are lost forCommands that are effective only when issued and whose effects are lost for
subsequent commands, like, a dwell command which instructs the tool tosubsequent commands, like, a dwell command which instructs the tool to
remain in a given configuration for a given amount of time.remain in a given configuration for a given amount of time.
CNC Programming:-CNC Programming:-
• ManualManual
– Write code directlyWrite code directly
• Computer-assistedComputer-assisted
– Draw cutter pathDraw cutter path
• CAD/CAMCAD/CAM
– Draw the partDraw the part
– Cutter path is generatedCutter path is generated

19. INFORMATION NEEDED BY AINFORMATION NEEDED BY A
CNCCNC
1. Preparatory Information: units, incremental or absolute
positioning.
2. Coordinates: X,Y,Z, RX,RY,RZ.
3. Machining Parameters: Feed rate and spindle speed.
4. Coolant Control: On/Off, Flood, Mist.
5. Tool Control: Tool and tool parameters.
6. Cycle Functions: Type of action required.
7. Miscellaneous Control: Spindle on/off, direction of rotation,
stops for part movement.
This information is conveyed to the machine through a set
of instructions arranged in a desired sequence Program.

20. G-codes:
• Preparatory Functions
• Involve actual tool moves.
M-codes: Miscellaneous
• Functions – involve actions
• Necessary for machining
• Spindle on/off, coolant on/off.
Most G-codes set the machine in a “mode” which stays inMost G-codes set the machine in a “mode” which stays in
effect until it is changed or cancelled by another G-code.effect until it is changed or cancelled by another G-code.
These commands are called “modal”.These commands are called “modal”.

21. G CodesG Codes
• G40 Cutter compensation –G40 Cutter compensation – cancelcancel
• G41 Cutter compensation –G41 Cutter compensation – leftleft
• G42 Cutter compensation-G42 Cutter compensation- rightright
• G70 Inch formatG70 Inch format
• G71 Metric formatG71 Metric format
• G74 Full-circle programmingG74 Full-circle programming offoff
• G75 Full-circle programmingG75 Full-circle programming onon
• G80 Fixed-cycle cancelG80 Fixed-cycle cancel
• G81-G89 Fixed cyclesG81-G89 Fixed cycles
• G90 Absolute dimensionsG90 Absolute dimensions
• G91 Incremental dimensionsG91 Incremental dimensions
• G00G00 Rapid traverseRapid traverse
• G01 Linear interpolationG01 Linear interpolation
• G02 Circular interpolation,G02 Circular interpolation,
CWCW
• G03 Circular interpolation,G03 Circular interpolation,
CCWCCW
• G04 DwellG04 Dwell
• G08 AccelerationG08 Acceleration
• G09 DecelerationG09 Deceleration
• G17 X-Y PlaneG17 X-Y Plane
• G18 Z-X PlaneG18 Z-X Plane
• G19 Y-Z PlaneG19 Y-Z Plane
• G20 Inch Units (G70)G20 Inch Units (G70)
• G21 Metric Units (G71)G21 Metric Units (G71)

22. M CodesM Codes
• M00M00 Program stopProgram stop
• M01M01 Optional program stopOptional program stop
• M02M02 Program endProgram end
• M03M03 Spindle on clockwiseSpindle on clockwise
• M04M04 Spindle on counterclockwiseSpindle on counterclockwise
• M05M05 Spindle stopSpindle stop
• M06M06 Tool changeTool change
• M08M08 Coolant onCoolant on
• M09M09 Coolant offCoolant off
• M10M10 Clamps onClamps on
• M11M11 Clamps offClamps off
• M30M30 Program stop, reset to startProgram stop, reset to start

23. N Codes:N Codes:
• Gives an identifying number for each block of information.Gives an identifying number for each block of information.
• It is generally good practice to increment each block number by 5 or 10 toIt is generally good practice to increment each block number by 5 or 10 to
allow additional blocks to be inserted if future changes are required.allow additional blocks to be inserted if future changes are required.
X,Y, and Z Codes:X,Y, and Z Codes:
• X, Y, and Z codes are used to specify the coordinate axis.X, Y, and Z codes are used to specify the coordinate axis.
• Number following the code defines the coordinate at the end of the moveNumber following the code defines the coordinate at the end of the move
relative to an incremental or absolute reference point.relative to an incremental or absolute reference point.
I,J, and K Codes:I,J, and K Codes:
• I, J, and K codes are used to specify the coordinate axis when defining theI, J, and K codes are used to specify the coordinate axis when defining the
center of a circle.center of a circle.
• Number following the code defines the respective coordinate for the centerNumber following the code defines the respective coordinate for the center
of the circle.of the circle.

24. F,S, and T Codes:F,S, and T Codes:
• F-code: used to specify the feed rateF-code: used to specify the feed rate
• S-code: used to specify the spindle speedS-code: used to specify the spindle speed
• T-code: used to specify the tool identification numberT-code: used to specify the tool identification number
associated with the tool to be used in subsequent operations.associated with the tool to be used in subsequent operations.
Main parts of a CNC program:Main parts of a CNC program:
• N5 G90 G21 (Absolute units, metric)N5 G90 G21 (Absolute units, metric)
• N10 M06 T2 (Stop for tool change, use tool # 2)N10 M06 T2 (Stop for tool change, use tool # 2)
• N15 M03 S1200 (Turn the spindle on CW to 1200 rpm)N15 M03 S1200 (Turn the spindle on CW to 1200 rpm)
• N20 G00 X1 Y1 (Rapid to X1,Y1 from origin point)N20 G00 X1 Y1 (Rapid to X1,Y1 from origin point)
• N25 Z0.125 (Rapid down to Z0.125)N25 Z0.125 (Rapid down to Z0.125)
• N30 G01 Z-0.125 F100 (Feed down to Z-0.125 at 100N30 G01 Z-0.125 F100 (Feed down to Z-0.125 at 100
mm/min)mm/min)
• N35 G01 X2 Y2 (Feed diagonally to X2,Y2)N35 G01 X2 Y2 (Feed diagonally to X2,Y2)
• N40 G00 Z1 (Rapid up to Z1)N40 G00 Z1 (Rapid up to Z1)
• N45 X0 Y0 (Rapid to X0,Y0)N45 X0 Y0 (Rapid to X0,Y0)
• N50 M05 (Turn the spindle off)N50 M05 (Turn the spindle off)

25. Drilling Operation

26. Milling Operation

27. Turning Operation

28. PROGRAM INPUT DEVICEPROGRAM INPUT DEVICE
The program input device is the mechanismThe program input device is the mechanism
for part programs to be entered into the CNCfor part programs to be entered into the CNC
control. The most commonly used programcontrol. The most commonly used program
input devices are keyboards, punched tapeinput devices are keyboards, punched tape
reader, diskette drivers, throgh RS 232 serialreader, diskette drivers, throgh RS 232 serial
ports and networks.ports and networks.

29. MACHINE CONTROL UNITMACHINE CONTROL UNIT
The machine control unit (MCU) is the heart of a CNC system.The machine control unit (MCU) is the heart of a CNC system.
It is used to perform the following functions:It is used to perform the following functions:
• Read coded instructionsRead coded instructions
• Decode coded instructionsDecode coded instructions
• Implement interpolations (linear, circular, and helical) toImplement interpolations (linear, circular, and helical) to
generate axis motion commandsgenerate axis motion commands
• Feed axis motion commands to the amplifier circuits forFeed axis motion commands to the amplifier circuits for
driving the axis mechanismsdriving the axis mechanisms
• Receive the feedback signals of position and speed for eachReceive the feedback signals of position and speed for each
drive axisdrive axis
• Implement auxiliary control functions such as coolant orImplement auxiliary control functions such as coolant or
spindle on/off, and tool changespindle on/off, and tool change

30. TYPES of CNC CONTROLTYPES of CNC CONTROL
SYSTEMSSYSTEMS
• Open-loop controlOpen-loop control
• Closed-loop controlClosed-loop control

31. OPEN-LOOP CONTROLOPEN-LOOP CONTROL
SYSTEMSYSTEM
• In open-loop control system step motors areIn open-loop control system step motors are
usedused
• Step motors are driven by electric pulsesStep motors are driven by electric pulses
• Every pulse rotates the motor spindle throughEvery pulse rotates the motor spindle through
a certain amounta certain amount
• By counting the pulses, the amount of motionBy counting the pulses, the amount of motion
can be controlledcan be controlled
• No feedback signal for error correctionNo feedback signal for error correction
• Lower positioning accuracyLower positioning accuracy

32. CLOSED-LOOP CONTROLCLOSED-LOOP CONTROL
SYSTEMSSYSTEMS
• In closed-loop control systems DC or ACIn closed-loop control systems DC or AC
motors are usedmotors are used
• Position transducers are used to generatePosition transducers are used to generate
position feedback signals for error correctionposition feedback signals for error correction
• Better accuracy can be achievedBetter accuracy can be achieved
• More expensiveMore expensive
• Suitable for large size machine toolsSuitable for large size machine tools

33. DRIVE SYSTEMDRIVE SYSTEM
A drive system consists of amplifier circuits,A drive system consists of amplifier circuits,
stepping motors or servomotors and ball lead-stepping motors or servomotors and ball lead-
screws. The MCU feeds control signalsscrews. The MCU feeds control signals
(position and speed) of each axis to the(position and speed) of each axis to the
amplifier circuits. The control signals areamplifier circuits. The control signals are
augmented to actuate stepping motors which inaugmented to actuate stepping motors which in
turn rotate the ball lead-screws to position theturn rotate the ball lead-screws to position the
machine table.machine table.

34. MACHINE TOOLMACHINE TOOL
CNC controls are used to control various typesCNC controls are used to control various types
of machine tools. Regardless of which type ofof machine tools. Regardless of which type of
machine tool is controlled, it always has amachine tool is controlled, it always has a
slide table and a spindle to control of positionslide table and a spindle to control of position
and speed. The machine table is controlled inand speed. The machine table is controlled in
the X and Y axes, while the spindle runs alongthe X and Y axes, while the spindle runs along
the Z axis.the Z axis.

35. FEEDBACK SYSTEMFEEDBACK SYSTEM
The feedback system is also referred to as theThe feedback system is also referred to as the
measuring system. It uses position and speedmeasuring system. It uses position and speed
transducers to continuously monitor thetransducers to continuously monitor the
position at which the cutting tool is located atposition at which the cutting tool is located at
any particular time. The MCU uses theany particular time. The MCU uses the
difference between reference signals anddifference between reference signals and
feedback signals to generate the control signalsfeedback signals to generate the control signals
for correcting position and speed errors.for correcting position and speed errors.

36. ADVANTAGES OF CNCADVANTAGES OF CNC
Utilization of computers in manufacturing applications has proved to beUtilization of computers in manufacturing applications has proved to be
one of the most significant advantages & developments over the last coupleone of the most significant advantages & developments over the last couple
of decades in helping to improve the productivity and efficiency ofof decades in helping to improve the productivity and efficiency of
manufacturing systems.manufacturing systems.
• Productivity
1. Machine utilisation is increased because more time is spent cutting and1. Machine utilisation is increased because more time is spent cutting and
less time is taken by positioning.less time is taken by positioning.
2. Reduced setup time increases utilisation too.2. Reduced setup time increases utilisation too.
• QualityQuality
1. Parts are more accurate.1. Parts are more accurate.
2. Parts are more repeatable.2. Parts are more repeatable.
3. Less waste due to scrap.3. Less waste due to scrap.

37. ADVANTAGES OF CNCADVANTAGES OF CNC
• Reduced inventoryReduced inventory
1. Reduced setup time permits smaller economic batch quantities.1. Reduced setup time permits smaller economic batch quantities.
2. Lower lead time allows lower stock levels.2. Lower lead time allows lower stock levels.
3. Lower stock levels reduce interest charges and working capital3. Lower stock levels reduce interest charges and working capital
requirements.requirements.
• Machining Complex shapesMachining Complex shapes
1. Slide movements under computer control.1. Slide movements under computer control.
2. Computer controller can calculate steps.2. Computer controller can calculate steps.
3. First NC machine built 1951 at MIT for aircraft skin milling.3. First NC machine built 1951 at MIT for aircraft skin milling.
• Management ControlManagement Control
1. CNC leads to CAD1. CNC leads to CAD
2. Process planning2. Process planning
3. Production planning3. Production planning

38. DRAWBACKS OF CNCDRAWBACKS OF CNC
• High capital costHigh capital cost
Machine tools cost $30,000 - $1,500,000Machine tools cost $30,000 - $1,500,000
• Retraining and recruitment of staffRetraining and recruitment of staff
• New support facilitiesNew support facilities
• High maintenance requirementsHigh maintenance requirements
• Not cost-effective for low-level production on simpleNot cost-effective for low-level production on simple
partsparts
• As geometric complexity or volume increases CNCAs geometric complexity or volume increases CNC
becomes more economicalbecomes more economical
• Maintenance personnel must have both mechanicalMaintenance personnel must have both mechanical
and electronics expertiseand electronics expertise

39. Programmable Logic Controllers
A PLC (Programmable Logic Controllers) is an
industrial computer used to monitor inputs, and
depending upon their state make decisions based on
its program or logic, to control (turn on/off) its
outputs to automate a machine or a process. It can
also be defined as a digitally operating electronic
apparatus which uses a programmable memory for
the internal storage of instructions by implementing
specific functions such as logic sequencing, timing,
counting, and arithmetic to control, through digital or
analog input/output modules, various types of
machines or processes

40. Programmable Logic Controllers

41. PLC SYSTEM
A programmable logic controller consists of the following
components:
1.Central Processing Unit (CPU)
2.Memory
3.Input modules
4.Output modules and
5.Power supply.
Programming
Terminal
CPU
Output
Modue
Memory
Power Supply
Input
Module

42. MAJOR COMPONENTS OF PLC
1. INPUT MODULES accepts and converts signals from sensors into a logic signal.
Ex. : Switches, Pushbuttons.
2. OUTPUT MODULES that convert control instructions a signal that can be used by
actuators. Ex. : lamps, alarm.
3. CENTRAL PROCESSING UNIT(CPU)
• It is the brain of PLC and governs the activities of the entire PLC systems
• The CPU performs the SCAN CYCLE for PLC.
• The CPU consists of following blocks : Arithmetic Logic Unit (ALU), Internal
memory of CPU, Internal timers, counters and Flags .
1. Timer is basically used add some delay in the programming circuit by adding a
particular time to each circuit.
a. Types of timers : - ON delay timer, OFF delay timer and Retentive Timers.
2. Counter works on the method of counting the number of pulse.
a. Types of Counters: UP counter, DOWN counter

43. MAJOR COMPONENTS OF PLC
• MEMORY is the component that stores information,
programs and data in a PLC.
• Types of memories used in PLCs are read only memory
(ROM) and random access memory (RAM).
5. POWER SUPPLY : Provides the voltage needed to run the
primary PLC components.
6. Programming device: The programming terminal is used for
programming the PLC and monitoring/sequencing PLCs
operation.

44. PLC ADVANTAGES AND DISADVANTAGES
ADVANTAGES
• Increased Reliability, flexibility and accuracy.
• Easier to troubleshoot.
• Remote control capability.
• Communication Capability.
• Handles much more complicated systems.
DISADVANTAGES
• Initial Costs Are High
• There's Too Much Work Required In Connecting Wires

45. PLC PROGRAMMING
Normally Open
(NO)
Power flows through these contacts when they are closed. The
normally open (NO) is true when the input or output status bit
controlling the contact is 1. The normally closed (NC) is true
when the input or output status bit controlling the contact is 0.
Normally Closed
(NC)

46. Coils:-
Coils represent relays that are energized when power
flows to them. When a coil is energized it causes a
corresponding output to turn on by changing the state
of the status bit controlling the output to 1. That same
output status bit maybe used to control normally open
or normally closed contact anywhere in the program.

47. Boxes:-
Boxes represent various instructions or functions that are executed when power
flows to the box. Some of these functions are timers, counters and math
operations.
AND OPERATION:-
Each rung or network on a ladder program represents a logic operation. In the
rung above, both inputs A and B must be true (1) in order for the output C to be
true (1).
Rung
A B C

48. OR OPERATION
In the rung above, it can be seen that either input A or B is be
true (1), or both are true, then the output C is true (1).
Rung
A
B
C

49. NOT OPERATION
Rung
A C
In the rung above, it can be seen that if input A is be true (1), then
the output C is true (0) or when A is (0), output C is 1.

52. CONCLUSION
This training has proved to be quite faithful. This gave me, a
chance to have an encounter with such heavy CNC machines.
The architecture of B.H.E.L. ,the way the various units are
linked and the way the working of the whole plant is
controlled, makes the student realize that engineering is not
just the structural description but more of planning and
management. It has provided an opportunity to learn that
optimization of technology used at proper place and time can
save a lot of labour.
The training has proved to be immensely helpful as it has
helped me to have an exposure of the practical implementation
of the theoretical knowledge that I have gained till date.