L&T-MHI Turbine Generators
44
SUMMER INTERNSHIP REPORT(JUNE-JULY, 2013)ON
TIME STUDY AND EVALUATION ON PROCESS PARAMETERS FOR MACHINING OF
HP PEDESTAL LOWER HALF
AT
L&T-MHI TURBINE GENERATORS PRIVATE LTD.HAZIRA, SURAT.
BY
PARTH GANDHITHIRD YEAR, MECHANICAL ENGINEERINGSARDAR VALLABHBHAI
NATIONAL INSTITUTE TECHNOLOGYINTERNSHIP DURATION: JUNE 16,
2014-JULY 16, 2014
CONTENTSSr. No.TOPICPage No.
1Acknowledgement3
2About the company4-8
3Steam Turbines9-18
4Induction19-23
5PROJECT: Time Study And Evaluation Of Process Parameters
24-38
65S System39-42
7Kaizen43-45
ACKNOWLEDGEMENT
I am thankful to a lot of people for helping me in what has been
an extraordinary venture, here at LMTG in the course of these four
weeks. It has been a great leapfrog from the last of adolescence
towards professionalism. Firstly, I would like to thank Mr. Aloke
Sarkar, General Manager, Production Department at LMTG, for giving
me an opportunity to be a part of this privileged company. He is an
inspiration to one and all.I would like to extend my gratitude to
my mentor Mr. Chetan Patil for their continued and uninterrupted
guidance and valuable wisdom throughout my work period.I would fail
in my duty if I dont thank Mr. Jigar Panchal, PPC Department, who
has been extremely helpful and generously thoughtful throughout my
journey at LMTG. His uncanny support made me feel a part of my new
workplace since day one. I would also like to admit that I would
not have been able to overcome the little problems faced by a
newbie if it were not for him.Last but not the least a special
thanks to all the operators, Nimesh Gangadiya and all, whose
support and co-operation cannot be disregarded.
ABOUT THE COMPANY
Larsen & Toubro Limited is an Indian multinational
conglomerate corporation headquartered in Mumbai, Maharashtra,
India. The company has business interests in engineering,
construction, manufacturing, information technology and financial
services. L&T is Indias largest engineering and Construction
Company, with a dominant presence in Indias infrastructure, power,
hydrocarbon, machinery and railway related projects. It is one of
the largest and most respected companies in Indias private sector.
More than seven decades of a strong, customer focused approach and
the continuous quest for world-class quality have enabled it to
attain and sustain leadership in all its major lines of business.
L&T has an international presence, with a global spread of
offices.
L&T believes that progress must be achieved in harmony with
the environment. A commitment to community welfare and
environmental protection are an integral part of the corporate
vision. In response to changing market dynamics, L&T has gone
through a phased process of redefining its organization model that
facilitates growth through greater levels of empowerment.
L&T-MHI Turbine Generators Private Limited, a JV between
L&T Power & MHI of Japan, manufactures supercritical steam
turbines of up to 1000 MW rating through a technology transfer
agreement with Mitsubishi Electric Corporation, Japan. The company
also manufactures generators to match the specified range. MHI
products have the added advantages of ease in maintenance,
reduction in vibration stresses and better performance in a
corrosive environment. The JV also offers state-of-the-art facility
for Generator Testing and High Speed Balancing.
MHI headquartered in Tokyo, Japan, is one the worlds leading
heavy machinery manufacturers, with consolidated sales of 2590
billion yen in fiscal 2004. Its diverse line up of products and
services encompasses shipbuilding, steel structures, power plants,
chemical plants, steel plants, environment equipment, industrial
& general machinery, aircraft, space rocketry and air
conditioning systems.
This is a joint venture for setting up a manufacturing facility
to supply supercritical turbines and generators which is further
licensed in technology and technical assistance agreement for
manufacture of supercritical generators between L&T MHI and
MELCO (Mitsubishi Electric Corporation, Japan.
JV Agreement was signed on November 5, 2007 and it was locked in
is for the term of 7 years. The technology license is in agreement
for the next 20 years.
L&T VISION
L&T shall be a professionally managed Indian multinational,
committed to total customer satisfaction and enhancing shareholder
value. L&T-ites shall be innovative, entrepreneurial and
empowered team, constantly creating value and attaining global
benchmarks. L&T shall foster a culture of caring, trust and
continuous learning while meeting expectations of employees,
stakeholders and society.
L&T MISSION
We are in the business of design and manufacturing of hi-tech
custom built, fabricated equipment/ vessels, system and related
services.We serve process industries in Oil and Gas Refinery,
Petrochemicals, Fertilizers and Chemicals, Power, Defense, Nuclear
and Shipbuilding.We shall attain the Global leadership in these
areas of business by pursuing opportunities in the international
market. We shall achieve this through total employee involvement
with emphasis on: Innovation, automation and continual improvement
Cycle time and cost reduction Focused manufacturing Efficient
working capital management Effective knowledge sharing and training
Safety, health & environment friendly practicesWe shall ensure
reliability and customer satisfaction with world-class quality
products and services.
LMTG MISSION
To emerge as a market leader in the field of Design, Manufacture
and Supply of Steam Turbines and Generators through continual
improvement, employee involvement and respect for environment.
FACILITIES AT LMTG The plant, encompassing 70 acres of land at
Hazira, is divided into a Production Shop, a Blade Shop, a
Packaging facility and an Administrative Block among major
establishments. Major Machine Tools Heavy Machines- 46 Medium
Machines- 38 Major Equipment- 59 (CNC Cutting, 200T Press, Furnace
,Shot Blast etc.,) Generator Test Bed (1000 MW) High Speed
Balancing ( 4500 rpm) Blade Manufacturing The Production Shop is
divided into six sub-divisions along with a Main Store. The six
sub-divisions are four Machine Shops and two Fabrication Shops,
being listed from T1 to T4 and T5 to T6 respectively.
PRODUCTS AT LMTG
LMTG receives first contract in March 2010. The company
manufactures tandem compounded steam turbines with the following
arrangement: First company in India to produce super-critical
turbines in-house. Produces 4000 MW barrier equipment in a year.
Efficiency of a sub-critical turbine is around 38-40% whereas that
of a super-critical turbine is around 42%. Ultra-super-critical
turbines have the efficiency of 45%. Unit sizes ranging from 500 MW
to 1000 MW. One 1000 MW turbine requires around 146,000 tons of
coal per day which needs around 7 boogie-trains per day delivering
it. Two 500 MW turbines more preferable over one 1000 MW turbine in
case one shuts down, other still operates. The combined HP/IP
turbine is applied to 500 MW, 600 MW and 800 MW while separated
HP/IP is provided for 1000 MW ratings. 500 MW has one LP turbine
while 600 MW has 1 or 2 depending on the temperature. 800 MW and
1000 MW have two sets of LP turbines.
Main steam pressure is 24.2 MPa and the temperature lies between
538C and 600C.
Steam parameters Main Steam Pressure 242 BarMain Steam Temp
above 500 CReheat Temp around 593 C
STEAM TURBINE
A steam turbine is a mechanical device that converts the heat
energy of steam to mechanical energy. This mechanical energy, in
the form of rotary motion of the turbine is particularly suited to
drive an electrical generator. The interior of a steam turbine
comprises of several blades. One set of stationary blades are
connected to the turbine casing and one set of rotating blades
connected to the shaft. The sets of intermesh with minimum
clearance, with the size and configuration of sets varying
efficiently exploit the expansion of steam at each stage.In large
power stations, the steam turbine is divided into three distinct
power stages, the first being high pressure (HP), the second
Intermediate pressure (IP) and the third low pressure(LP). Separate
cylinders for IP and HP stage can be used or both the turbines can
be housed in one casing and called HIP turbine. This combining is
done mainly to reduce the axial thrust on the shaft. Other
advantages include lesser rotor length and lesser components used.
Steam turbines can be configured in many different ways. Several IP
or LP turbines can be incorporated into one steam turbine. A single
shaft or several shafts coupled together may be used.
CLASSIFICATION OF STEAM TURBINES
Application Industrial Utility Exhaust of Steam Condensing Back
Pressure Number of cylinders Single Double Triple Arrangement of
Cylinders Cross Compounded Tandem Compounded Design Principle
Impulse Reaction Type of Governing Throttle Nozzle Speed Full Speed
Half Speed
STEAM TURBINE & ITS WORKING PRINCIPLE
Steam Turbine is one of the principle equipment of a thermal
power plant along with boiler, condenser and heaters which work
together on closed liquid vapour cycle. Steam turbine is regarded
as a prime mover which rotates the generator for producing
electricity.
The driving force for rotation in turbine is generated by
superheated steam supplied from boiler. The potential energy of
superheated steam available in the form of pressure, temperature
& heat is converted into kinetic energy in the row of fixed
blades arranged circumferentially to form nozzles. The high
velocity steam generated at the expense of pressure drop in nozzles
passes through this row; the steam reverses its path which gives
rise to change in momentum. This change develops driving force
according to second law of Newton, which states that whenever there
is change in momentum an impressed force is generated, which is
proportional directly to rate of change of momentum. Since these
blades are mounted on shaft, which is free to rotate, the developed
force starts rotating the shaft.
A set of fixed blades forming nozzles and rotating blades
mounted on shaft is called a stage of turbine. Depending upon steam
condition and output; a number of such stages are envisaged in
turbine. Aim is to have gradual pressure drop so as to reduce
losses and abrupt changes. The torque produced by each stage gets
added up and total is available at the coupling end to turn
generator and produce electric power.
PICTORIAL VIEW OF A STEAM TURBINE
SUPERCRITICAL TECHNOLOGY
Supercritical technology has evolved over the past 30 years.
Advancements in metallurgy and design concepts have made
supercritical technology units extremely reliable and highly
efficient. Modern supercritical technology is largely available in
Japan and Europe for Boilers & Turbines ranging upto 1000
MW.The term "supercritical" refers to main steam operating
conditions, being above the critical pressure of water (221.5
bars). The significance of the critical point is the difference in
density between steam and water. Above the critical pressure there
is no distinction between steam and water, i.e. above 221.5 bar,
water is a fluid.If the steam pressure is greater than 275 bars,
then conditions are Ultra Supercritical.
Supercritical steam cycle with one reheat.
a b: Condensate cycle up to Deaeratorc : Boiler feed pump
dischargec d : Feed water heatingd e : Main steam generatione f:
Expansion in turbinef g : Reheat steam generationg h : Expansion in
turbine
In supercritical cycle, equipment is designed to operate above
the critical pressure of water. Supercritical boilers are
once-through where in the feed water enters the economizer and
flows through one path and main steam exits the circuit. Typically
current supercritical units operate at 242 bar main steam pressure,
565C main steam temperature and 593C reheat steam
temperature.Advantages Of Modern Supercritical Technology
HIGHER EFFICIENCY: Supercritical steam conditions improve the
turbine cycle heat rate significantly over sub-critical steam
conditions. The extent of improvement depends on the main steam and
reheat-steam temperature for the given supercritical pressure. A
typical supercritical cycle having turbine throttle pressure of 242
bar with temperatures for main steam and reheat steam as 565C and
593C respectively, will improve station heat rate by more than 5%.
This results in fuel savings to the extent of 5%. Overall
supercritical power plant efficiency of 42% is achievable with
current supercritical parameters. If the unit size is increased,
both fuel cost and additional investment per MW reduces.
EMISSIONS: Improved heat rate results in 5% reduction in fuel
consumption and hence 5% reduction in CO2emissions per MWh energy
output. Supercritical technology based thermal power project is a
potential candidate to avail the benefits under Clean Development
Mechanism (CDM) established by United Nations Framework Convention
on Climate Change (UNFCCC).
OPERATIONAL FLEXIBILITY: Supercritical technology units also
offer flexibility of plant operation such as:
Shorter start-up times Faster load change flexibility and better
temperature control Better efficiency even at part load due to
variable pressure operation High reliability and availability of
power plantMAIN COMPONENTS OF A STEAM TURBINE
Blades Turbine Casing Rotor Gland Seals Couplings Bearings
Bearing Pedestals Stop & Control Valves Governing System
Lubrication System Drain System Control & Instrumentation
Turning Gear
Turbine Blades: Blades are the key component of turbine as
conversion of energy to develop driving force takes place therein.
The blades which form nozzles and are fixed are called stationary
or guide blades. The blades mounted on rotor are called moving
blades.
Turbine Casing: The guide blades of various stages are held in
the stationary body called casing. It also acts as a cover for
steam passage with connections for steam admission, exhaust and
other flows.
Rotor: It holds the moving blades of various stages in the
grooves machined in it.
Gland Seals: Since turbine casing and rotor are respectively
stationary and rotating parts, there is bound to be clearance
between the two at the ends. The steam tries to escape through
these clearances causing working atmosphere non conducive in power
station for working personnel. To minimize this leakage, gland
seals are provided at the two ends of turbine.
Couplings: They connect the rotor s together and transmit the
torque finally to generator for turning.
Bearings: For supporting the rotors at the two ends to enable
them rotate freely bearings are provided. These bearings are
journal bearings supplied with forced lubrication. Ball bearings
are not suitable as they are not capable to take high loads.
Bearing Pedestal: They support the bearings and house the lube oil
piping and drain oil pipe work. They also enclose various
instrumentation which monitors healthiness of turbine during
operation.
Stop & Control Valves: Turbine does not run at full load at
all the times. Its output is regulated by the electric grid it is
connected. For producing power, matching to varying load demand,
the supply of steam quantity is regulated by control valves. For
taking care of emergency situations stop valves are also provided
which cut off the supply of steam turbine under such situation.
They have only two positions either fully open or fully closed.
Governing System: An elaborate governing system is provided for
turbine to control the opening of control valves to supply amount
of steam according to varying load demand. The system senses the
load variation in the form of speed change, convert it to hydraulic
signal, amplify it and operate the actuators/ servomotors coupled
to control valves. Apart from load changes, the system also acts
during emergency situations to safe guard the turbine. The system
comprises of mix of electronic, electrical & hydraulic
devices.
Lubrication System: The TG journal bearings are provided with
forced lubrication so as to form hydraulic film between journal
& bearing surface to support the rotor. During the course of
running the lube oil gets heated up due to friction and need to be
cooled, filtered, purified and pumped back to bearings. A closed
lubrication system consisting of a reservoir, pumps, filter cooler
and purifier forms the essential part of turbine. Drain System:
During non steady state operating conditions, the mismatch between
turbine component metal temperatures and steam causes condensation
which gets collected in piping & casings. This condensate is
withdrawn by drain system otherwise it would flash back during load
changes and deform casing rotor and blading.
Control & Instrumentation: During operation a host of
parameters e.g. steam pressure, temperatures, lube oil pressure
temperature, metal temperatures, expansions, rotor speed &
eccentricity etc. are continuously monitored, supervised through
various instruments and supervisory devices. On the basis of these
control & instruments, safe, reliable and uninterrupted
operation of turbine within defined design limits is ensured.
Turning Gear: A turning gear is provided to rotate the turbine
rotor slowly prior to start-up and after the turbine is shutdown to
allow unified warm-up and cooling, maintain eccentricity and to
prevent the thermal distortion of the rotor. It can be electric
motor driven unit and in others oil driven driving unit/hydraulic
motor.
INDUCTION At very first day of induction T1 SHOP was introduced
where I learnt about different types of rotors like HP, HIP, IP,
LP1, and LP2. The machining processes were being done on all CNC
based lathe, milling, turning machines. Here the Rotor for turbine
and generator is made with very accurately and with use of latest
machines like SIDE ENTRY GROOVE machine, which is absolutely new
for me. In T2 SHOP the casings for turbine and generators casing
which are made either from casting or fabrication are machined and
certain quality of them are being checked and improved. Here Indias
largest machine GANTRY PLANOMILLER is used for machining heavy
castings without moving them, but by moving gantry. Also here VTL
(vertical turning lathe), HBM (horizontal boring machine), EDM
(electro discharge machining). In T3 SHOP machining operations are
done on machines which are mentioned above as per the requirement
and quality consideration. Also here deburring and finishing
operations are done for removing stress from component and make
them super finished. The project work was allotted in this machine
shop. In T4 SHOP fabrication is being carried out. The casings for
LP1 & LP2 rotors which have large volume and density are being
fabricated here. Here also gantry Plano miller is used for
machining heavy fabricated casings.
T5 & T6 SHOP(FABRICATION SHOP)In this shop, Basic machining
operations are done on small components of turbine and generator
section. Here surface grinding, CNC plasma cutting machine, tool
point grinder, pipe bending, regrinding machine, radial drilling
machine , cutting tool edges maker, hydraulic press are different
types of machines used for respective operations. Also Shot
blasting Process (to remove rust), Painting(to protect against
corrosion), and Gas fired Bogie Hearth Batch type Heat treatment
furnace(to reduce stress) are used on components. Also internal
threading , automatic tool changer, sine bar for levelling, surface
attachments on milling machine, different types of JIGS &
FIXTURES , GO & NOGO gauges, etc. very useful and informative
parameters are known by me. Also heat treatment furnace for heating
and removing stresses and strains from object and further cooling
is done for v making it very hard and sustainable for high load
capacity.Also, Different types of welding machines like TIG, MIG,
SMAW, GMAW, etc. are used. The welding processes are done according
to type of joint and accuracy customer want. Here also STATOR FRAME
VERTICAL FABRICATION & SIMPLE STATIONARY BLADE MACHINE, welding
for big blades MANIPULATOR POSITIONER WELDING MACHINE is used.
TURBINE ASSEMBLY
HIP ASSEMBLY FLOWCHARTInterference check of inner components
with respect to outer componentsGland Bore settingHIP Outer Casing
LevelingHIP Casing Hydro Test
Top halves installationRotor TravelRotor TravelClearance
AdjustmentInner components installation
LP ASSEMBLY FLOWCHARTOuter Casing Lower InstallationOuter Casing
Upper InstallationRotor InstallationRotor TravelLP Bore
Adjustment
Steam Deflector InstallationSteam Chamber InstallationInner
casing L/H installation & centering
Gland Ring InstallationSpecial Stationary Blade Installation
Installing upper components & measuring top clearanceBottom
Clearance Adjustment
BLADE SHOPIn this shop, different types of blades like
stationary blade and rotating blade with different dimensions are
made on CNC based 5 axis and 4 axis machines also having quality
department and tool length measurement device which is very
essential and adequate. The coordinates of blade are tested
accurately by using CMM (Coordinate measuring machine), Profile
Projector and Weight balancing Machine. The tools are very highly
finished for making very sensitive and adequate part of turbine,
blades.The blade path consists of reaction blades in the high
pressure turbine, intermediate pressure turbine and low pressure
turbine. The reaction type blading is adopted in large turbines
because of its high efficiency. In the reaction blade path, the
steam velocity is relatively slow resulting in lower friction loss
namely better aerodynamic efficiency.
Blades have 3 principal parts:i. Aerofoil/Profile sectionii.
Rootiii. Shroud
Roots are classified into:i. Hook rootii. T-rootiii. Fir tree
rootiv. Finger/Fork rootv. Axial Fir tree root
STATOR COIL SPRING SHOPIn this shop, copper strap as raw
material which are finally converted into coil of copper which are
the root of magnetic field. Roebelling operation is done on coil
strap for joining proper number of coil straps and makes one unit.
After that consolidation and framing is done. Brazing and tapping
with specially insulated material tap is done on 6 axis machine for
making coil hard. Afterwards vacuum pressure impregnation and
polymerization is done on it in big vacuum chamber with semi
insulated painting on it.After that curing at 135 c is done for at
least 24 hours. Finally by using core model the copper coil is made
in definite final shape and then it is sent to assembly area.
STATOR COIL MANUFACTURING FLOWCHART:
PROJECT SUBJECT: TIME STUDY AND EVALUATION OF PROCESS
PARAMETERSMENTOR: MR. CHETAN PATIL (T3 MACHINE SHOP)My project is
to study the basic processes which are being done on particular
machine with consideration of PPS and drawing chart of particular
object.For performing this project first of all I visit the T3 SHOP
completely, note down the specifications of each and every machine.
Then I was allotted the COMPONENT called HP PEDESTAL LOWER HALF on
VERTICAL PRECISION MILLING MACHINE (PM202) OR ST13. The object is
to study the PPS of HP PEDESTAL LOWER HALF and compare the
SMH(Standard Man Hours) timings with actual timing of the workers
and engineers of L&T taken to complete the job.X-AXIS
(TABLE)9000 MM
Y-AXIS (VERTICAL HEAD)4900 MM
Z-AXIS (RAM)1000 MM
W-AXIS (CROSS RAIL)2200 MM
DISTANCE BETWEEN COLUMNS4300 MM
MAX HEIGHT OF JOB3050 MM
RAM SIZE(400400) MM
TABLE SIZE(80003500) MM
SPINDLE DIA AND TAPER130 MM/ISO 50
SPINDLE SPEED4000 RPM
SPINDLE POWER45 KW
The specifications of the PM202 (made by Mitsubishi, Japan) are
as follows:BEARING AND BEARING PEDESTALS
The Bearing performs the following functions: - It retains the
rotor in correct radial position with respect to the cylinder. It
provides low friction support and withstand dynamic load of
rotating shaft. It takes away the heat generated due to
friction.
Each turbine rotor has two journal bearings for both ends, and
one shaft system has one thrust bearing. They are all of forced
lubricated type, i.e., the load is carried by hydrodynamically
generated film of lube oil. The bearing surface is made of Babbitt
metal which is an alloy having low coefficient of friction and an
excellent conductor of heat.
For cooling & lubrication, oil is supplied at about 1 to 1.5
bar pressure through oil pump. Temperature of oil is maintained at
30-35C. All the bearings have thermocouples for detecting the metal
and oil drain temperatures. The turbine is incorporated with
grounding device to prevent the shaft voltage trouble.
Bearing Pedestal performs the following functions: - It supports
the rotor via journal bearing & maintaining gland clearances
& also inter-stage clearances. It houses the lubricating &
jacking oil supply piping & bearing oil drain pipe work.
Encloses various instrumentation connections. E.g. bearing
temperature, speed measurement, differential expansion,
electricity, vibration pick-up, etc. It covers the rotor coupling.
Oil guard rings provided at the two ends of pedestals prevents the
leakage of oil & vapors.
MethodologyFirst of all I studied the PPS of HP PEDESTAL LOWER
HALF and note the basic standard timing for completion of
object.Then the analysis of drawing, that exactly what it is and
how the machining operations are done on it, in which order, with
how much tolerances and which operation are difficult to
process.Then I watched the whole process done by operators on HP
PEDESTAL LOWER HALF step by step and calculate amount of actual
time required by them to complete the component.Then we match the
actual time with planned time and we find that actual time was more
than planned time but not by larger quantity.
COMPARISON FOR LAST 3 PROJECTS
CASE STUDY ROUGHING OF BOTTOM FACE: Planned time (By SMH) 4
hours 18 minutes Theoretical program time 5 hours 4 minutes Actual
time 11 hours 46 minutesProblemCauses Corrective ActionExtra Time
Taken
2 extra passes had to be takenDepth of cut chosen was 2mm less
than the planned value. An extra 2 hours 32 minutes of machining
had to be done to compensate. 2 hours 32 minutes
2 extra passes had to be takenExtra material of 5mm was
presentAn extra 2 hours 32 minutes of machining had to be done to
compensate. 2 hours 32 minutes
Insert wear outInserts have to be replaced after every 1-2
passes. This replacement takes time.Include an estimate of the time
taken for this in the planning or select working ranges in which
this would not happen.
Insert changeFor a tool with 16 inserts, up to 20 minutes per
pass was used in replacing worn out inserts.This time should be
considered while calculating the approximate machining time. 1 hour
20 minutes
Offset had to be taken againFor every tool and insert change,
the offset had to be taken again.Extra time was taken to take the
offset again.40 minutes
Development of chips and coolant accumulationAnytime material
removal is done, metal chips are developed and have to be cleared.
Cleaning both takes approx. 5 minutes per pass.No corrective action
possible. Necessary action done to ensure correct finish.40
minutes
Use of extension headExtension head installed could not operate
at the desired cutting depth. -
Different cutting speeds, feeds and depth of cutValues
prescribed in the PPS are difficult to match due to a variety of
reasons.Timings in the PPS are ideal. They should be made in
cohesion with production so as to have a better estimate of
possible parameters.
Machining of oil groove: Planned time (by SMH) 2 hours 6 minutes
Theoretical program time 2 hours 34 minutes Actual time 4
hoursProblemsCauses Corrective ActionTime Taken
Drilling done to generate slotDrilling had to be done to set the
starting point for further machining.Extra time taken to drill the
hole should be added to the PPS as it is a part of machining time.1
hour
Time taken for setupSetting of the drilling tool and taking
offset for the same took up extra time. Can be added to the PPS as
setup time for this operation.10 minutes
Development of chips and coolant accumulationAnytime material
removal is done, metal chips are developed and have to be cleared.
Cleaning both takes approx. 5 minutes per pass.No corrective action
possible. Necessary action done to ensure correct finish.40
minutes
Different cutting speeds, feeds and depth of cutValues
prescribed in the PPS are difficult to match due to a variety of
reasons.Timings in the PPS are ideal. They should be made in
cohesion with production so as to have a better estimate of
possible parameters.
WHAT I LEARNT FROM IT? I got to know about different type of
tools and inserts used for different processes. I also study the
nomenclature and geometry of tools as well as inserts which are
used for machining. By studying this I understood the insert
geometry and nomenclature with respect to different processes also
tool geometry which is mentioned below:
Tool Nomenclatures For external turningMInsert Clamping
System
CInsert Shape
KTool holder Style
NInsert clearance angle
RHand of Tool
C, S, FAdditional information
25 25Shank Dimension
MTool length
12Insert size cutting edge length
For internal Turning
AConstruction featuring boring bar
25Shank dimensions
RLength of boring bar
MInsert clamping system
CInsert shape
LBoring bar style
NInsert clearance angle
RHand of tool
12Insert size cutting edge length
INSERTS NOMENCLATURESCInsert Shape
NInsert clearance angle
MTolerance class
GInsert features
12Size
04Thickness
08Corner radius, Hand of insert, Cutting edge
FMChip breaker
I came to know the basic process from operator by understanding
loading condition, speed overwrite, feed overwrite, spindle
overwrite, rpm, reference machining, maximum rotation diameter,
coolant condition, chip conveyor arrangement, jigs and fixtures,
tooling parts, dial gauge for levelling and centering, measuring
devices, inserts, jaws and blocks and clamps, etc. As per working
on this project I came to know very basic fundamental but new
things like different types of inserts, clamping arrangement, very
innovative magnetic chuck which is very user friendly and no
clamping is required for that. It is very time saving parameter
also it has some drawbacks like chip removal and unloading of
object etc. but overall it is very good experience. During this I
also came to know how to calculate feed and depth of cut by
calculating rpm from range of cutting speed which is based upon job
material, insert material, clamping condition, coolant and tool
condition, past experience. I studied about the test done after
machining which is done by quality department like DPT (DYE
PENETRATE TEST), remote visual inspection, radiographic testing and
low coherence interference to find defects in the component. Here
also I understood the industrial management terms like wise EHS
(ENVIRONMENTAL HEALTH AND SAFETY), 5 S,TBT (TOOL BOX TALK), HJS
(HORIZONTAL JOINT SURFACE), ROUTE CARD, NCR (NON CONFORMANCE
REPORT), PPS (PROCESS PLANNING SHEET), TOOLING LIST, PREVENTIVE AND
PREDICTIVE MAINTENANCE CHECK SHEET etc. I also got to know about
different process terms like spot facing, back spot facing, weld
edge and dry run. Also, I learnt the use of the Go-NoGo Gauge from
my project mentor, who also taught me how to use the same while
checking the threading performed internally in holes and bores on
the machined surface.
OBSERVATION Clogging of chips around the tool and the component
that is machined makes it difficult to do the process properly.
Excess use of coolant. It should be used within permissible limits
as sometimes coolants goes in part of component where it is not
required. Many times tools of the machine are taken by other
machine operators or by other shop which sometimes stops the
machining of component which increases actual time of machining.
Leakage of air is observed in many machine and may be leading to
losses. Also there is misuse of compressed air in the purposes
where it is not required. At many instances, the operators ran the
various operations at speeds lesser than the prescribed values,
resulting in the need for multiple passes and therefore, more time
than what is listed in the Standard Man Hours for the operation.
Usually operators stops working during the last hour of their shift
and would spend the time idle. This time can be used up for other
purposes or at the very least another pass can be completed in the
idle time. There are not proper schedule for worker to operate the
crane or EOT (Electrical Overhead Transport), resulting in increase
in Standard Man Hours for the operation.
SUGGESTIONS For removing the chips during machining the workers
used to remove it by a steel rod which is dangerous and may also
affect the surface finish of the component. For that there should
be CHIP BREAKERS fitted with tool point, which will break the chips
in discontinuous fashion, resulting in less clogging of chips
around the component and between the job and the cutting edge of
the tool. A set no. of tools should be present at every machine for
all basic purposes. The usage of coolant should be regulated in a
way to extend the usable life of the coolant. In many cases,
multiple tubes or faucets delivering the coolant were switched on,
some of which werent even aimed at the surface being machined,
thereby causing major wastage of the coolant, which cannot be
circulated permanently and has to be replaced after set periods of
time. This can be implemented by properly observing and supervising
the usage of coolant at the time of operation and then instructing
the operators as to the proper use.
APPRAISAL POINTS First of all, the KNOWLEDGE SESSION which is
arranged at every Wednesday is very good idea to share the
knowledge with other executives and relevant departments. By
attending this type of sessions one can easily enhance its
engineering knowledge and being aware about how much productivity
the company is doing at current going time. Second point is the
planning and arrangement of each and every useful part which are
necessary for operation. 5 S principles and KAIZEN principles are
very seriously implemented which will surely affect the efficiency
of department. Proper guidance and instructions are given to
workers at the start of each and every shift. The orientation of
each machines and cleaning staff is very good also the safety
feature is at its peak level which should be praised as per the
accidental damages to keep in mind. Proper specifications boards
are available at each machine so visitor can easily identify
particular machine with their code also. Safety is major aspect
they are concerned about.
CONCLUSION
Thus this Summer Training for almost 30 days was very
interesting and respective colleagues and engineers keep us willing
to know more and more.Also it will be very useful for me to get the
practical industrial based knowledge, their criteria, latest
machines and latest machining processes which are carried out
nowadays.It will also be an industrial experience as my further
carrier is in this field only. So it will be very fruitful if I
connect it with my theoretical knowledge and get the best
output.
5S SYSTEM
Definition: A systematic approach to workplace organization and
methodical house keeping with a sense of purpose.
1. SEIRI (Sorting)Identify and sort to segregate usable from
non-usable.STEPS Remove all garbage and unnecessary tools from shop
floor Remove all unnecessary papers from files Discard old files
and stationary not in use Clean walkways Saves floor space Helps
get rid of obsolete items
2. SEITON (Systematic arrangement)A rational orderly and
methodical arrangement of all items we use, rework or write
off.STEPS Ensure rational layout of machines, equipments and
cabinets Place frequently used items at the point of use Pre-fix a
place for everything and put everything in place Use labels, colour
codes to identify Use index for files, records and drawings Plan
storage with easy retrievability Mixed up items in cabinets should
be organized Make cabinets, shelves, racks self-explanatory through
identification aids
BENEFITS Material easily available Material easily retrievable
Lesser production downtime Machines breakdown handled fast Time
taken for searching is minimized
3. SEISO (Pick and Plan)Cleaning is not done not just for
beautification but also with a sense of purpose. Sweeping floors
and surroundings Dusting to make the place dust free Wiping to make
oil, grease, moisture free Identifying root causes and establishing
corrective action
STEPS Develop standards of cleaning Clean-up workplace after use
Clean-up machines and tools after use Clean-up supply lines (no
leakage, blockage, clogging with oil & dirt) Assign clear
responsibilities and schedules for cleaning Clean waste bins at end
of shift/day Clean light bulbs, fans, shades, reflectors Pay
special attention to scrap yard, gardens and godowns Scrap and
chips from machines could fall directly into collecting bins
ADVANTAGES Clean machines and floor Fast corrective action Tools
well laid out Smoother material flow Inventory levels can be found
visually Lesser production downtime
4. SEIKETSU (Standardization, Serene atmosphere)Following of
earlier 3 Ss, standardized work procedures, maintaining safe and
hygienic conditions in work place contribute to a serene working
atmosphere.STEPS Wear neat and clean uniform Wear protective
clothing Provide adequate lighting, ventilation, exhaust Check
electrical wiring, cable, switches Maintain sanitary conditions in
washrooms, locker rooms, canteen and kitchen Look for heavy noise,
vibration and heat in machines, analyze for root cause and take
action
5. SHITSUKE (Self-Discipline)Training, sincerity constancy of
purpose in following the rules and standards developed in the
earlier 4 Ss.STEPS Create awareness of 4S Make them easily
understandable Display correct work procedure on the floor Correct
the deviations on the spot Maintain punctuality
BENEFITS OF 5S Nice to work in a clean, beautiful and organized
work place. Reduction in M/C down time. Lesser time to retrieve
things when required. Improved communication among employees.
Improved morale of employees. Sense of ownership of workplace.
Positive impact on the customer. More usable space. Higher
productivity. Lesser accidents. Reduction in errors/defects due to
standardization. Consistent improved quality.KAIZENKaizen, Japanese
for "improvement", or "change for the better" refers to philosophy
or practices that focus upon continuous improvement of processes in
manufacturing, engineering, and business management. It has been
applied in healthcare, psychotherapy, life-coaching, government,
banking, and other industries. When used in the business sense and
applied to the workplace, kaizen refers to activities that
continually improve all functions, and involves all employees from
the CEO to the assembly line workers. It also applies to processes,
such as purchasing and logistics, that cross organizational
boundaries into the supply chain. By improving standardized
activities and processes, kaizen aims to eliminate waste (see lean
manufacturing). Kaizen was first implemented in several Japanese
businesses after the Second World War, influenced in part by
American business and quality management teachers who visited the
country. It has since spread throughout the world and is now being
implemented in many other venues besides just business and
productivity.The Japanese-Kanji- word "kaizen" simply means "good
change", with no inherent meaning of either "continuous" or
"philosophy" in Japanese dictionaries or in everyday use. The word
refers to any improvement, one-time or continuous, large or small,
in the same sense as the English word "improvement".[5] However,
given the common practice in Japan of labeling industrial or
business improvement techniques with the word "kaizen" (for lack of
a specific Japanese word meaning "continuous improvement" or
"philosophy of improvement"), especially in the case of
oft-emulated practices spearheaded by Toyota, the word Kaizen in
English is typically applied to measures for implementing
continuous improvement, or even taken to mean a "Japanese
philosophy" thereof. The discussion below focuses on such
interpretations of the word, as frequently used in the context of
modern management discussions.Kaizen is a daily process, the
purpose of which goes beyond simple productivity improvement. It is
also a process that, when done correctly, humanizes the workplace,
eliminates overly hard work ("muri"), and teaches people how to
perform experiments on their work using the scientific method and
how to learn to spot and eliminate waste in business processes. In
all, the process suggests a humanized approach to workers and to
increasing productivity: "The idea is to nurture the company's
human resources as much as it is to praise and encourage
participation in kaizen activities."[6] Successful implementation
requires "the participation of workers in the improvement."[7]
People at all levels of an organization participate in kaizen, from
the CEO down to janitorial staff, as well as external stakeholders
when applicable. The format for kaizen can be individual,
suggestion system, small group, or large group. At Toyota, it is
usually a local improvement within a workstation or local area and
involves a small group in improving their own work environment and
productivity. This group is often guided through the kaizen process
by a line supervisor; sometimes this is the line supervisor's key
role. Kaizen on a broad, cross-departmental scale in companies,
generates total quality management, and frees human efforts through
improving productivity using machines and computing power.The cycle
of kaizen activity can be defined as: Standardize an operation and
activities. Measure the operation (find cycle time and amount of
in-process inventory) Gauge measurements against requirements
Innovate to meet requirements and increase productivity Standardize
the new, improved operations Continue cycle ad infinitum
Parth Gandhi
