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1. INTRODUCTION TO D.L.W.
Diesel Locomotive Works (DLW) is production unit under the ministry of
railways. This was setup in collaboration with American locomotive company
(ALCO) USA in 1961 and the first locomotive was rolled out in 1964. This unit
produces dieselelectronic locomotives and DG sets for Indian railways and other
customers in India and Abroad. Subsequentlya contractfor transfer of technology
of4000 HP MicroprocessorControlled AC/AC Freight (GT 46 MAC) /passenger
(GT 46 PAC) locomotives and family of710 engines has been signed with electro
motive division of general motors of USA for manufacture in DLW. The
production of these locomotives has now started and thus DLW is the only
manufacturers of Diesel Electric Locomotives with both ALCO and General
motors technologies in the world.
1.2. Brief History
Set up in 1961 as a green-field project in technical collaboration with
ALCO/USA to Manufacture Diesel Electric Locomotives.
First locomotive rolled out and dedicated to nation in January 1964.
Transfer-of-Technology agreement signed with General Motors/ USA in
October1995 to manufacture state-of-the-art high traction AC-AC diesel
A flagship company of Indian Railways offering complete range of flanking
products in its area of operation.
State-of-the art Design and Manufacturing facility to manufacture more than
150 locomotives per annum with wide range of related products viz.
components and sub-assemblies.
Unbeatable trail-blazing track record in providing cost-effective, eco-
friendly and reliable solutions to ever-increasing transportation needs for
over three decades.
Fully geared to meet specific transportation needs by putting Price-Value-
Technology equation perfectly right.
A large base of delighted customers among many countries viz. Sri Lanka,
Malaysia, Vietnam, Bangladesh, Tanzania to name a few, bearing testimony
to product leadership in its category.
1.3. SALIENT FEATURES
Annual production capacity 125 Locomotives
Annual turn-over (Rs.) 5000 million
Total number of staff 7223
Workshop land 89 Hectares
Township area 211 Hectares
Covered area in shops 86300 Sq.m
Covered area of other service buildings 73700 Sq.m
Electrical power requirement (Average maximum demand) 3468 KVA
Electrical energy consumption (units/year) 19.8 million
Stand by power generation capacity 3000 KW
1.4. PRODUCT OF DLW:
DLW is an integrated plant and its manufacturing facilities are flexible in nature.
Thesecan be utilized formanufacture of different design oflocomotives of various
gauges suiting customer requirements and other products. The product range
available is as under:
WDG4 4000 HP AC/AC Freight traffic Locomotive
WDP4 4000 HPAC/AC Broad Gauge High Speed Locomotive
WDG3D 3400 HP AC/AC Broad Gauge Mixed Traffic Micro-
Processor Controlled Locomotive
WDM3C 3300 HP AC/DC Broad Gauge Mixed Traffic
WDM3A 3100 HP AC/DC Broad Gauge Mixed Traffic
WDP3A 3100 HP AC/DC Broad Gauge High Speed Passenger
WDG3A 3100 HP AC/DC Broad Gauge Freight Locomotive
WDM2 2600 HP AC/DC Broad Gauge Mixed Traffic
i. Our Vision: "To be a World class manufacturer of Diesel Electric
ii. Our Mission:"We shall achieve our vision through Continuous
Improvement in the areas of Product Quality, Research and
Development, Supplier Partnership, Human Resource Development
and Team Work with emphasis on Core Competence Leading to
Customer Satisfaction And Business Excellence."
iii. Our Quality Policy:"Weare committed to Excellence in all Activities
and Total Customer Satisfaction through Continuous Improvement in
Quality of Products and Services."
iv. Our Quality Philosophy:
Quality is not controlled but produced;
Emphasis is on quality in all organizational processes;
Regular quality audit as per ISO procedures;
Top Management totally committed to quality in all
1.6. QUALITY ASSURANCE
Quality has been a crusadein DLW since its very inception. We actively inculcate
the primary importance of manufacturing a quality product in all our workmen,
supervisors and engineers from the day they join DLW. Each of our workmen is
continually trained and re-trained in Quality aspects. Moderninstrumentation and
machinery help the workmen in maintaining a high standard of quality. Under
ISO 9002 certification scheme, all our jigs and fixtures, tools and gauges are
calibrated regularly according to a carefully worked out plan.
DLW has a fully equipped Gauge Room for calibration of gauges, and a
tool room for checking of jigs and fixtures. Rigorous standards of certification
for DLW's vendors, almost all bought-out items are subjected to quality checks
and certified by our incoming inspection. Now DLW's Quality thrust has been
certified by an internationally accredited ISO certifying body, and DLW is proud
owner of ISO 9002 certificate for the entire range of manufacturing activities.
1.7. HUMAN RESOURCES DEVELOPMENT
Battery of highly skilled, motivated and trained man-power treated as the
most important organizational asset;
Peoplecentric participative style ofmanagement with societal orientation.
Training forms a continuous part of organizational culture;
Staff trained at General Motors, USA facilities as a part ofnew agreement
reached with them;
Management totally committed to healthy Industrial Relations, Staff
welfare and Safety;
Excellent industrial safety track record by adopting all round safety
measures and conducting regular safety audits;
1.8. EMPLOYEE BENEFITS
DLW is committed to provide best possible staff welfare;
Facilities and competent medical/ paramedical staff to meet any medical
A well-equipped and modern 90 bed hospital with latest fully self-sufficient,
and eco-friendly Township for employees sprawling over 211 hectares, in the
vicinity of work-place;
1.9. ENVIRONMENT & OUR SOCIETY
At DLW, we firmly believe that no organization can operate in vacuum
and therefore, we owe a lot not only to the environment we breath in but also to
the society we live in. Our environmental policy and other social goals enshrine
this commitment and are reflected in all our activities.
1.10. ENVIRONMENTAL POLICY
We, at Diesel Locomotive Works, Varanasi, while carrying out Chrome-
plating and Wastewater Treatment will continually strive to minimize the
impact of our activities on the environment. We will minimize the resource
consumption and waste generated from these shops to make our surroundings
greener and cleaner.
We shall comply with all applicable environmental regulations.
1.12. RESEARCH & DEVELOPMENT
R & D - a Customer centric Activity Committed to Innovation and Continuous
Highly skilled Manpower capable of handling complete R&D activities;
A sophisticated design center with modern CAD/ CAE workstations equipped
with Unigraphics and Ansys;
Back-up support from RDSO, a centralized R&D organization at corporate
Several milestones in the past - an enviable pedigree viz.
R&D strategy aims at absorption of new technology, up-gradation of existing
processes, improvement in tool designs and machining facilities, development of
new products and special processes for world-class quality - thus helping our
customers to succeed..........
1.13. RECENT MILESTONES & FUTURE PLAN
1.14. MILESTONES ACHIEVED
Transfer of technology (TOT) -- An added feather in the cap:-
Agreement with General Motors of USA for technology transfer to
manufacture high horse-power GT46MAC 4000HP AC/AC locomotive
Only country outside North-America to have this bleeding edge
Many export/repeat orders complied successfully in recent past and
many more in the pipeline;
1.15. FUTURE PLANS
Assimilation of GM technology to manufacture their latest 710 series ofdiesel
To emerge as a globally competitive locomotive manufacturer;
To develop as an export hub for ALCO/ GM locos for Asian market;
To follow an export led growth strategy through continuous improvement;
Cost effectiveness and technology/ product up-gradation as a key to retain
global competitiveness by putting price-value-technology equation right.
2. ALLOTED WORKSHOP
I have been allotted the following workshops in my four week vocational training.
2. Machine Lab TTC
3. Indian Railway Welding Research Institute
4. Loco Paint Shop
3. Indian Railway Welding Research Institute
Welding is a process which produce joining of materials by heating them
to suitable temperatures with or without the application of pressure and with or
without the use of filler materials.
Welding is use for making permanent joint. It is use in the manufacturing
of automobile bodies, aircraft frame, machine frame, railway wagons, general repair
works, boiler etc.
3.1 TYPE OF WELDING USE IN D.L.W
3.1.1 Shielded Metal Arc Welding [ 𝐒𝐌𝐀𝐖]
Shielded metal arc welding (SMAW), also known as manual metal arc
welding (MMA or MMAW), flux shielded arc welding or informally as stick
welding, is a manual arc welding process that uses a
consumable electrode covered with a flux to lay the weld.
Fig. 3.1.1 (a) Operation of SMAW
An electric current, in the form of either alternating current or direct
current from a welding power supply, is used to form an electric arc between the
electrode and the metals to be joined. The work piece and the electrode melts
forming the weld pool that cools to form a joint. As the weld is laid, the flux
coating of the electrode disintegrates, giving off vapours that serve as a shielding
gas and providing a layer of slag, both of which protect the weld area from
Because of the versatility of the process and thesimplicity of its equipment
and operation, shielded metal arc welding is one of the world's first and most
popular welding processes. It dominates other welding processes in the
maintenance and repair industry, and though flux-cored arc welding is growing
in popularity, SMAW continues to be used extensively in the construction of
heavy steel structures and in industrial fabrication. The process is used primarily
to weld iron and steels (including stainless steel)
but aluminium, nickel and copper alloys can also be welded with this method.
Shielded metal arc welding equipment typically consists of a constant
current welding power supply and an electrode, with an electrode holder, a
'ground' clamp, and welding cables (also known as welding leads) connecting the
Fig. 3.1.1 (b) System setup
The choice of electrode for SMAW depends on a number of factors,
including the weld material, welding position and the desired weld properties.
The electrode is coated in a metal mixture called flux, which gives off gases as it
decomposesto prevent weld contamination, introduces deoxidizers to purify the
weld, causes weld-protecting slag to form, improves the arc stability, and
provides alloying elements to improve the weld quality.
1. Lower equipment cost than GTAW, FCAW and GMAW. (No bottle, gas
hose, flow meter, and trig rig/Wire feeder needed.
2. Quick Change from one material to another.
3. The process lends itself to welding in confined spaces and various positions
with few problems.
4. Deposition Rates faster than GTAW Manual
5. Easy to move from one location to another. No Wire Feeder and Bottle.
6. Some special electrodes are made for cutting/gouging
7. Requires no outside shielding gas and can be used outdoors in light to
8. The ability to bend the electrode and the small space the electrode takes
allows the process to be used in comparatively tight spaces. However keep
in mind that forsomejobs one of the other processesmayalso work or even
work better. The FCAW-Self Shielded process can weld with a very long
1. Low deposition rate compared to GMAW/FCAW.
2. Filler metal costper weld can be greater due to a low deposition
efficiency that can vary greatly with stub length.
3. Production factor is typically lower (Unless welding on various materials)
due to rod changes and chipping slag.
4. Needs more hand eye coordination than GMAW/FCAW.
5. Slag must be removed as compared to GTAW/GMAW
1. Used to weld carbonsteel, low and high alloy steel, stainless steel, cast iron,
and ductile iron.
2. The thickness of the material being welded is bounded on the low end
primarily by the skill of the welder, but rarely does it drop below 1.5 mm
3. SMAW can be used in any position
3.1.2 Submerged arc welding [ 𝐒𝐀𝐖]
In SAW the welding heat source is an arc - maintained between a
consumable electrode and the work piece. The arc and molten metal are
"submerged" in a blanket of granular fusible flux. The electrode is continuously
fed into the arc and additional flux is distributed in front as the weld head moves
along the joint
Submerged arc welding (SAW) is a common arc welding process.
Submerged arc welding (SAW) is so named because the weld and arc zone are
submerged beneath a blanket of flux. The flux material becomes conductive
when it is molten, creating a path for the current to pass between the electrode
and the work piece. The flux blanket prevents spatterand sparks, while shielding
ultraviolet light and fumes that are normally a partofshielded metal arc welding.
The flux usually is supplied to the welding head via a small hopper. A collection
system gathers the excess flux for reuse.
The process uses one or more continuously fed electrodes (wires) to
maintain an arc. SAW is known for its ability to depositlarge amounts of metal
quickly, consistently, and safely. The basic SAW equipment is a power source,
control unit, wire unit, and nozzle.
Fig 3.1.2(a) Working principal of SWA
Power and Control
On the input side, it is no longer necessaryto use single-phase power only.
The new machines can connect to three-phase power and the same power supply
used for both. This is achieved simply bymodifying a plug so current and voltage
remain stable and consistent. Inverters make it possible to use the same piece of
equipment anywhere in the world.
State-of-the-art SAW controls are all digital, allowing constant feedback
for monitoring and changing voltage, amperage, wire feed speeds, and so forth
Digital PLCs are set up to interface with the application selected at the power
source, and in some cases one controller can handle any choice of AC, DC CV,
or DC CC.
Travel Speeds and Consumable Materials
The flexibility of the new power sources allows manufacturers to focus on
faster travel speeds, which enhance quality in high-deposition welds.
'In the '50s and '60s the tractors were huge. Now they are much smaller and
can work faster," Fisher said.
One of the concerns with early SAW was variable feed speeds of the
tractor. Now tractors equipped with speed control can change speed when the
load changes, keeping other variables more constant. Adaptability is still the
name of the game, so even modular tractors can be taken apart without tools to
be passed through small spaces where they are reassembled to perform necessary
operations. These high-end tractors are extremely versatile in what they can do.
SAW also makes good of strip cladding, a process that debuted in the
1960s. The consumable is a metal or alloy strip—measuring 0.79 to 4.72 in. wide
and about 0.020 in. thick—which is used in place of a common wire electrode.
The arc passes between the strip and the work piece, while the flux shields the
weld from the atmosphere and the operator from spatter. This is another option
to achieve high deposition and eliminate a number of passes.
• Functions of the electrode: -
- Conducts electrical current to the arc
- Supplies joint filler material
•Electrodes may consist of :–
- solid rod or wire
- composite electrode (a metallic sheath encasing metal powders)
• Functions of the flux
- Establish the electrical characteristics of the electrode and arc
- Controlthe composition and metallurgy of the weld deposit
- Supply additional filler material
- Control weld bead shape.
• Flux constituents
- The flux consists ofgranular minerals and metals in the form of fused and
crushed or bonded agglomerated particles.
• Power Supply
- Constant current orconstant voltage type 100% duty cycle 1000 A output
• Wire Feeder
- Constant speed (for constant voltage power supplies) or voltage sensing
(for constant current power supplies)
• Travel & Positioning Device
- e.g. weld head crawler or rotary positioner
• Flux delivery/recovery system
• Process Controls
- Welding current, travel/work piece positioning, wire feed sequencing.
• Joining heavy sections in steel, stainless steels
- Pressure vessel & piping circumferential & longitudinal seams
- Plate girder fabrication
- Ship panel subassembly
- Multi-wire & strip cladding variants
1. Molten flux provides very suitable conditions for high current to flow. Great
intensities of heat can be generated and kept concentrated to weld thicker
sections with deep penetrations.
2. Because of high heat concentration, considerably higher welding speeds can
3. Because of high heat concentration and high welding speeds weld distortion
is much less.
4. High metal deposition rates cane be achieved. Single pass welds can be made
in thick plates with normal equipment.
5. Welding is carried out without sparks, smoke, flash or spatter.
6. Weld metal deposit possessesuniformity, good ductility, corrosionresistance
and good impact strength.
7. Very neat appearance and smoothweld shapes can be got.
8. The submerged process canbe used for welding in exposed areas with
relatively high winds.
9. Practically, no edge preparation is necessary for materials under 12 mm in
1. Since the operator cannot see the welding being carried out, he cannot judge
the progress of welding accurately. Therefore accessories like jigs and fixtures,
pointers, light beam focusing devices or roller guides may be used for proper
welding at the joint.
2. The flux needs replacing of the same on the joint which is not always possible.
3. The progress is limited to welding in flat position and on the metal more than
4.8 mm thick. In small thicknesses burn through is likely to occur.
4. The process requires edge preparation and accurate fit up on the joint.
Otherwise the flux may spill through the gap and arc may burn the work piece
5. Flux is subjected to contamination that may cause weld porosity.
6. Weld metal chemistry is difficult to control. A change in welding variables
especially when using alloyed fluxes may affect weld metal composition
7. Cast iron, Al alloys, Mg alloys, Pb and Zn cannot be welded by this process.
3.1.3 Gas Metal Arc Welding [ 𝐆𝐌𝐀𝐖]
GMAW is the most common industrial welding process, preferred for its
versatility, speed and the relative ease of adapting the process to robotic
automation. Unlike welding processes that do not employ a shielding gas, such
as shielded metal arc welding, it is rarely used outdoors or in other areas of air
volatility. A related process, flux cored arc welding, often does not use a
shielding gas, but instead employs an electrode wire that is hollow and filled
GMAW was soonapplied to steels because it provided faster welding time
compared to other welding processes. The cost of inert gas limited its use in
steels until several years later, when the use of semi-inert gases such as carbon
dioxide became common.
Fig3.1.3.(a) working principle of GMAW
To perform gas metal arc welding, the basic necessary equipment is a
welding gun, a wire feed unit, a welding power supply, a welding electrode wire,
and a shielding gas supply.
Welding gun and wire feed unit
The typical GMAW welding gun has a number of key parts—a control
switch, a contact tip, a power cable, a gas nozzle, an electrode conduit and liner,
and a gas hose. The control switch, or trigger, when pressed by the operator,
initiates the wire feed, electric power, and the shielding gas flow, causing an
electric arc to bestruck. The contact tip, normally made of copperand sometimes
chemically treated to reduce spatter, is connected to the welding power source
through the power cable and transmits the electrical energy to the electrode while
directing it to the weld area. It must be firmly secured and properly sized, since
it must allow the electrode to pass while maintaining electrical contact. On the
way to the contact tip, the wire is protected and guided by the electrode conduit
and liner, which help prevent buckling and maintain an uninterrupted wire feed.
The gas nozzle directs the shielding gas evenly into the welding zone.
Inconsistent flow may not adequately protect the weld area. Larger nozzles
provide greater shielding gas flow, which is useful for high current welding
operations that develop a larger molten weld pool. A gas hose from the tanks of
shielding gas supplies the gas to the nozzle. Sometimes, a water hose is also built
into the welding gun, cooling the gun in high heat operations.
The top electrode holder is a semiautomatic air-cooled holder. Compressed
air circulates through it to maintain moderate temperatures. It is used with lower
current levels for welding lap or butt joints. The second most common type of
electrode holder is semiautomatic water-cooled, where the only difference is that
water takes the place of air. It uses higher current levels for welding T or corner
joints. The third typical holder type is a water cooled automatic electrode
holder—which is typically used with automated equipment.
Most applications of gas metal arc welding use a constant voltage power
supply. As a result, any change in arc length (which is directly related to voltage)
results in a large change in heat input and current. A shorter arc length causes a
much greater heat input, which makes the wire electrode melt more quickly and
thereby restore the original arc length. This helps operators keep the arc length
consistenteven when manually welding with hand-held welding guns. To achieve
a similar effect, sometimes a constant current power source is used in
combination with an arc voltage-controlled wire feed unit. In this case, a change
in arc length makes the wire feed rate adjust to maintain a relatively constant arc
length. In rare circumstances, a constantcurrent powersourceand a constantwire
feed rate unit might be coupled, especially for the welding of metals with high
thermal conductivities, such as aluminum. This grants the operator additional
control over the heat input into the weld, but requires significant skill to perform
Electrode selection is based primarily on the composition of the metal
being welded, the process variation being used, joint design and the material
surface conditions. Electrode selection greatly influences the mechanical
properties of the weld and is a key factor of weld quality. In general the finished
weld metal should have mechanical properties similar to those of the base
material with no defects such as discontinuities, entrained contaminants or
porositywithin the weld. To achieve these goals awide variety ofelectrodes exist.
All commercially available electrodes contain deoxidizing metals such
as silicon, manganese, titanium and aluminum in small percentages to help
prevent oxygen porosity. Some contain denigrating metals such as titanium
and zirconium to avoid nitrogen porosity. Depending onthe process variation and
base material being welded the diameters of the electrodes used in GMAW
typically range from 0.7 to 2.4 mm (0.028 – 0.095 in) but can be as large as 4 mm
(0.16 in). The smallest electrodes, generally up to 1.14 mm (0.045 in) are
associated with the short-circuiting metal transfer process, while the most
common spray-transfer process mode electrodes are usually at least 0.9 mm
Shielding gases are necessary for gas metal arc welding to protect the
welding area from atmospheric gases such as nitrogen and oxygen, which can
cause fusion defects, porosity, and weld metal embrittlement if they come in
contactwith the electrode, the arc, orthe welding metal. This problem is common
to all arc welding processes; for example, in the older Shielded-Metal Arc
Welding process (SMAW), theelectrode is coated with a solid flux which evolves
a protective cloud of carbon dioxide when melted by the arc. In GMAW,
however, the electrode wire does nothave a flux coating, and a separate shielding
gas is employed to protect the weld. This eliminates slag, the hard residue from
the flux that builds up after welding and must be chipped off to reveal the
Formostofits applications gas metal arc welding is a fairly simple welding
process to learn requiring no more than a week or two to master basic welding
technique. Even when welding is performed by well-trained operators weld
quality canfluctuate since it depends onanumber ofexternal factors. All GMAW
is dangerous, though perhaps less so than some other welding methods, such as
shielded metal arc welding.
As mentioned above, the GMAW process is possible the most widely used
process in the United States. This is due to several advantages. Below are listed
several of these advantages:
1. Low costequipment – a hobby welder can get a welding machine from a
reputable manufacturer suchas Lincoln Electric or ITW for less than $600.
Add a few dollars for shielding gas and mig wire and you are welding for
less than $700.
2. Low cost consumables – out of all the process the consumables for mig
welding have the lowest cost. You can purchase mig wire from a big box
store for less than $3 per pound. Or you can go to a local industrial
distributor and get it for closer to $2 per pound.
3. High depositionrates – especially when compared to stick welding. With
the GMAW process you can deposit up to nearly 10 pounds per hour
(deposited weld metal).
4. Low hydrogen deposits – since solid does not pick up moisture like flux-
cored wires and stick electrodes it consistently deposits welds with low
levels of diffusible hydrogen. You can learn more about why this is
important by reading “WHY WELDS CRACK”
5. Can weld almost all metals – by simply changing your filler wire and at
times the shielding gas you can weld from carbon steel, to stainless steel,
to nickel alloys and aluminum.
6. Low levels of spatter – low spatter can be achieved by selecting the right
mode of metal transfer. Spray and pulse welding can provide this benefit.
To learn more read “MODES OF METAL TRANSFER”
7. Unlimited thickness – this process allows for welding light gage material
and up to unlimited thickness by using multiple passes. Higher amperages
and proper joint configuration are needed to weld.
8. Easy to learn – unlike tig welding or stick welding, mig welding is easy
9. Little cleanup – since mig welding is a slagless process itdoes notrequire
chipping slag, cleaning up flux or discarding unused stick stubs.
10.High electrode efficiencies– the GMAW process provides efficiencies of
93-97%. This means that if you buy 100 pounds of mig wire you will be
deposition 93 to 97 pounds of weld metal. A process like SMAW (stick
welding) has electrode efficiencies of around 65%. This is due to loss due
to spatter, slag, and not consuming the entire electrode.
11.Input voltages – If you have electric service you can weld. Smaller
machines can run on 115 volt input. These machines are limited to about
¼” welding thickness. Some of the newer industrial machines are capable
or running anywhere from 208 to 575 input voltage on either single or
three-phase circuits. Most mig welding machines can also run off of
1. Sensitive to contaminants – the process can only handle low to
moderate levels of surface contaminants such as rust, mill scale, dirt, oil
and paint. All these have potential to create problems such as porosity,
incomplete fusion, bad bead appearance and even cracking.
2. Portability – moving the welding equipment may not be that tough, but
you also have to handle the high pressure cylinders that contain the
shielding gas. Proper care must be taken.
3. Sensitive to wind – the shielding gas used for mig welding can easily
be blown away when welding outdoors. Even inside, a fan or a wind draft
of as low as 5mph can be enough to cause porosity.
4. Lack of fusion – due to the ability to weld at low currents this process
has the potential for lack of fusion when running in short circuit mode.
Make sure you always use the correct procedure for the thickness of
material you are welding. There is a reason why the American Welding
Society does not have pre-qualified procedures using the short-circuit
mode of metal transfer.
5. Open arc process – as with most welding process, GMAW exhibits an
open arc. Proper care must be taking to shield the welder and bystanders
from the harmful UV rays.
3.1.4 Flux-cored arc welding (FCAW or FCA)
Flux-cored arc welding (FCAW or FCA) is a semi-automatic or
automatic welding process. FCAW requires a continuously-fed consumable
tubular electrode containing a flux and a constant-voltage or, less commonly, a
constant-current welding power supply. An externally supplied shielding gas is
sometimes used, but often the flux itself is relied upon to generate the necessary
protection from the atmosphere, producing both gaseous protection and
liquid slag protecting the weld. The process is widely used in construction
because of its high welding speed and portability.
FCAW was first developed in the early 1950s as an alternative to shielded metal
arc welding (SMAW). The advantage of FCAW over SMAW is that the use of
the stick electrodes used in SMAW is unnecessary. This helped FCAW to
overcome many of the restrictions associated with SMAW.
Fig 3.1.4 (a) Working principal of FACW
Flux Core Arc Welding (FCAW) uses a tubular wire that is filled with a
flux. The arc is initiated between the continuous wire electrode and the work
piece. The flux, which is contained within the coreof the tubular electrode, melts
during welding and shields the weld pool from the atmosphere. Direct current,
electrode positive (DCEP) is commonly employed as in the FCAW process.
There are two basic process variants; self-shielded FCAW (without
shielding gas) and gas shielded FCAW (with shielding gas). The difference in the
two is due to different fluxing agents in the consumables, which provide different
benefits to the user. Usually, self-shielded FCAW is used in outdoor conditions
where wind would blow away a shielding gas. The fluxing agents in self-shielded
FCAW are designed to not only deoxidize the weld pool but also to allow for
shielding of the weld pool and metal droplets from the atmosphere.
The flux in gas-shielded FCAW provides for de oxidation of the weld pool
and, to a smaller degree than in self-shielded FCAW, provides secondary
shielding from the atmosphere. The flux is designed to supportthe weld poolfor
out-of position welds. This variation of the process is used for increasing
productivity of out-of-position welds and for deeper penetration.
Wire feed speed (and current)
Travel speed and angle
Electrode wire type
Shielding gas composition (if required)
Reverse polarity (Electrode Positive) is used for FCAW Gas-Shielded wire,
Straight polarity (Electrode Negative) is used for self-shielded FCAW
Fig3.1.4(b) Equipmentof FCAW
FCAW may be an "all-position" process with the right filler metals (the
No shielding gas needed with some wires making it suitable for outdoor
welding and/or windy conditions
A high-deposition rate process (speed at which the filler metal is applied)
in the 1G/1F/2F
Some "high-speed" (e.g., automotive) applications
As compared to SMAW and GTAW, there is less skill required for
Less preleasing of metal required
Metallurgical benefits from the flux suchas the weld metal being protected
initially from external factors until the slag is chipped away
Mild and low alloy steels
Some high nickel alloys
Some wear facing/surfacing alloys
Porosity chances very low
Melted ContactTip – happens when the contact tip actually contacts the base
metal, thereby fusing the two and melting the hole on the end
Irregular wire feed – typically a mechanical problem
Porosity – the gases (specifically those from the flux-core) don’t escape the
welded area before the metal hardens, leaving holes in the welded metal
More costly filler material/wire as compared to GMAW
The equipment is less mobile and more costly as compared to SMAW or
The amount of smoke generated can far exceed that of SMAW, GMAW, or
Changing filler metals requires changing an entire spool. This can beslow and
difficult as compared to changing filler metal for SMAW or GTAW.
4. Machine Lab TTC
A machine shopis a room, building, orcompanywhere machining is done.
In machine shop, machinists use machine tools and cutting tools to make parts,
usually of metal or plastic (but sometimes of other materials such as glass or
In which the generally lathe machine are used for this purpose.
In this section all kinds of machining is done to obtain the correctsize and shape
of the job. Besides, machining of steel job, Aluminum-plates are also machined
here. Machining is other performed manually or on automatic machines.
Machines are two types…
There are three types of automatic machine.
1. Numerical control.
2. Computer numerical control.
3. Direct numerical controlmachine.
NUMERICAL CONTROL-Themachining parameter are feed from the
control panel by pushing buttons .The job is machined according to the
parameter There are N.C. boring machine in this shop.
COMPUTER NUMERICAL CONTROL- In this machine all the data
corresponding to the initial work piece to the final product is feed into the
computer. All the process required in the order of action is fed with the help of
programmer .In this machine one, has to just fix the job is to the chuck. All the
other process is done automatically. This is the machine use for large scale
production. In this shop there is one CNC chucker turret Lathe machine.
DIRECT NUMERICAL CONTROL-This machine is controlled by installing
a control room away from the work place .These machine are D.N.C. machine.
These are fully automated .The machine shop is divided into different divisions
to the task accomplished .Theses sections are-
1. Capstan and turret lathe section.
2. Milling section.
3. Drilling section.
4. Central lathe section.
5. Heavy machine section.
Lathes are very versatile. They are usually used to machine (turn) round
(cylindrical) parts, butcanalso producemany unique and irregular shapes.Alathe
can drill, ream, turn, knurl, cut and shape cylindrical parts. The type of machine
in the UCR Mechanical Engineering Machine Shop is a manual lathe, also known
as a tool room lathe. Although there are several other types of LATHES, this
document will focus only on the manual lathe. They are also known as tool room
lathes and/or engine lathes.
Normally, a part is held in a collet or lathe chuck and a cutting tool is held
in a tool post. The lathe is switched on and the part begins to rotate. The cutting
tool is then brought to the rotating part and removes material.
Fig. 4 (a) Lathe Machine
BASIC MACHINE PARTS
SPINDLE LOCK KNOB
For keeping the spindle from rotation when tightening or loosening collets.
For accurately holding the tailstock spindle.
TAILSTOCK HAND WHEEL
Formoving the tailstock spindle toward or away from the workpiece.
For holding drill chucks or lathe centers in the tailstock.
SPINDLE SPEED DISPLAY
Shows the spindle speed in Rotations Per Minute (RPMs).
SPINDLE SPEED KNOB
For adjusting the speed of the lathe spindle.
Moves the tool post, cross slide toward or away from the chuck.
For shutting off the spindle rotation and feeds in caseof an emergency!
For holding small diameter work pieces in the spindle of the lathe.
For holding and quickly changing between different ToolHolders.
Forholding lathe bits and other lathe cutting tools.
COMPOUND SLIDE HAND WHEEL
Formanually feeding cutting tools at an angle to the spindle.
CROSS SLIDE HAND WHEEL
For manually feeding cutting tools across the spindle (the X axis).
CARRIAGE HAND WHEEL
For manually feeding cutting tools in line with the spindle (the Z axis).
CROSS SLIDE FEED LEVER
For turning the auto feed for the cross slide on and off.
CARRIAGE FEED LEVER
Forturning the auto feed for the carriage on and off.
SPINDLE ON/OFF & DIR. LEVER
For turning the spindle on or off and for setting the rotation direction.
To determine the direction of the carriage or cross slide auto feed.
Fig . 4 (b) Lathe Machine component
USING THE MACHINE
1. Three important elements.
In order to get an efficient process, good surface finish and correct geometry on
the lathe, it is important to adjust the rotating speed (RPM), a cutting depth and a
feed speed. Please note that these important elements cannot be decided easily,
because these suitable values are quite different for each material.
• ROTATION SPEED
It is the number of rotations per minute (rpm) of the chuck or collet. When
the rotating speed is high, higher removal rates are possible. But when too high,
too much friction could be generated. However, since a little operation mistakes
may lead to the serious accident, it is better to set lower rotating speed at the first
• CUTTING DEPTH
The cutting depth of the tool affects to the processing speed and the
roughness of surface. When the cutting depth is big, the processing speed
becomes quick, but the surface temperature becomes high, and it has rough
surface. Taking off too much material can break the tool or your workpiece. If
you do not know a suitable cutting depth, it is better to set to small value. Always
remove a very small amount of material on your final pass to assure a good
• FEED SPEED
The feed speed of the tool also affects to the processing speed and the
roughness of surface. When the feed is high, you can remove a lot of material
quickly. When the feed is low, the surface improves. There are automatic feeds
on these machines that can move the feed handles for you at a very accurate feed.
These auto feeds maintain a consultant speed and result in nicer finishes. A
beginner must always use the manual mode, until they have enough experience.
A user should hold the handle ofthe automatic feed until the operation is complete
and never walk away. Serious accidents may occur if the tool bit or any part of
the post or the cross slides touch the collet or chuck!
2. Common lathe cutting tools.
Always use the correctand properly sharpened toolfor the job. Dull tools lead to
bad surface finishes, out of tolerance parts and potentially a hazard situation.
Below are the three most common types of lathe tools.
• THE LATHE BIT
The image above shows the most common lathe cutting tools, they are
called lathe bits. These can cut outside surfaces and edges. There are versions
that consistof a piece of carbide brazed onto a rectangular steel bar. The ones in
the above image are called “insert lathe tools.” It is because they have a carbide
insert that can be replaced or rotated when they become dull. This is ideal for
those that have little or no experience in grinding their own tools.
• THE CUT OFF TOOL
This tool(shown above) is also called a “parting tool.” It is primarily used
for cutting off (aka, parting) the work piece and making outside grooves. This
tool can only cut “across” the part in one direction (along the X axis).
• THE BORING BAR
This tool (shown above) is mainly used to make diametrical (round) holes
of any size and depth. Normally used to cut at an inside surface. It can make a
hole that is much bigger and more accurate than a regular drill. The other big
advantage is that a boring bar canmake irregular diameter holes with flat bottoms.
Drills and reamers are only available in “standard” sizes, but a boring bar does
not have that limitation. In mostcases, there needs to be an existing hole to fit the
boring bar. This hole can be produced with the use of a regular drill bit.
3. Clamping work-pieces using a Lathe Chuck.
A chuck is directly attached to the drive mechanism (spindle) of the lathe
and rotates at variable speeds up to as much as 1000 rpm on this machine. A 3 or
6 jaw chuck has the ability to hold a wide range of cylindrical parts from .250”
diameter, all the way up to 8” diameter.
To start, the operator clamps the piece of metal to be turned in the chuck.
Depending on the size (diameter and/or length) of the part, will determine how
much of it will need to be clamped in the chuck. Thesechucks are very accurate,
but pieces of metal are not always perfectly straight and level. So it is
recommended that you use a dial indicator to check the concentricity your work
piece in relationship to the machine. This can be doneby placing the indicator on
top of the tool post with the dial stem touching the part and with the machine
turned OFF, rotating the chuck by hand. Depending on the required precision, it
is important to check the trueness of the part to within one or two thousands of
Once you are sure that the part is true, tighten the chuck as tight as
necessary to hold the part without damaging the clamping surface. This is done
by placing the "chuck key" in the key receptacle on the side of the chuck and
turning it clockwise. NEVER LEAVE THE KEY IN THE CHUCK!!! Place the
chuck key on the workbench, away from all moving parts. If the key is left in and
the machine started, serious bodily harm will result! Check once more for “true”
if the precision is necessary. Before even starting the machine, spin the chuck by
hand to make sure it clears the carriage, cross slide, tools, tool post and/or all
other parts of the machine!
There are also 4 jaw chucks where each jaw can beadjusted independently,
these are for off-center lathe work and require special training. Consult the shop
supervisor if your parts need this tool.
The spinning jaws on a chuck are very dangerous. At certain speeds, the
jaws become an invisible blur! In a noisy environment, a spinning chuck may
not appear to be spinning. Always be aware ofthe jaws as you are working on the
lathe! Keep your hands, body and cutting tools well away from the chuck at all
4. Clamping work-pieces using the collet chuck.
A collet chuck takes the place of a 3, 4/ or 6 jaw chuck. It uses collets to
hold diameters ranging from .125” to 1.313”. Since it relies on collets and has no
spinning jaws, it is more accurate and safer way to hold your work. Make sure
that the diameter of your work piece matches the size of the collet within (+/-)
.015” Any larger variations and the work piece could slip or the collet could be
Make sure the spindle is OFF and not rotating before inserting orremoving
collets or work pieces! Also, you should move the tailstock and carriage/saddle
away from the collet chuck. The collet is inserted into the collet chuckby aligning
the “key”. You have done this correctly when the collet slips almost completely
into the collet chuck. Place your work piece into the collet (at least 1” in for most
diameters!). Then tighten the collet bypressing and holding the spindle lock knob
and simultaneously rotating the collet chuck wheel away from you. To loosen the
collet, press and hold the spindle lock knob and simultaneously rotate the collet
chuck wheel toward you. It might take several rotations to release your part.
5. Tool post and cutting tool set-up.
The toolpostis where the cutting tool and holder will be located. The tool
postuses a dovetail design to enable a user to pre-set a number of tools for easy
and accurate changes between cutting tools. The tool post is permanently
mounted to the machine, but canbe move and rotated. The toolholders have knob
on top to quickly adjust cutting tool heights.
Forsafe and efficient cutting, the tip ofthe tool must be located directly on
the center of the part in the chuck! Too high and the base of the tool will pushon
the part. This may damage your work piece or break the cutting tool. If the tool
is set too low, the tip of the tool will tend to gouge and/or cut too deep. It will
also leave an undesirable “nub” when you reach the center of the work piece.
A quick trick forsetting the toolheight is to gently squeeze a 6” metal scale
between the cutting tool and your work piece with the machine OFF and spindle
stopped. Have the shop supervisor show you how to do this properly and easily.
This technique will get you very close to the ideal tool cutting height with most
6. Moving the carriage and cross slide.
The carriage moves along the “ways” toward and away from the chuck(the
Z axis). The cross slide moves toward and away from the center or the part (the
X axis). The carriage and the cross slide are both moved manually by using hand
wheels. The cross slide hand wheel has dials that show DIAMETRICAL
distances. Each graduation on the hand wheel indicates .001”of diameter
movement of your tool. Movement of the carriage is measure with the use of a
dial indicator mounted on the left side of the carriage. It is limited to 2 inches of
travel for measurement purposes, but can be set anywhere along the carriage’s
In addition, there are two levers on the carriage that turn on the carriage
and cross feed “powerfeeds.” One feeds (moves) the carriage at a predetermined
speed and the other feeds the cross-slide. There is also a (push/pull) knob that
changes the direction of both feed levers! To understand these features, you
should test these operations well away from the chuck, at different speeds and
while supervised. This will enable you to get the feel ofthe automated movements
of the machine.
7. Compound slide
A compound slide is a smaller version of the cross feed with one major
difference, it can be set at any angle. It offers a way to turn tapers and cut angles
on a lathe. Mostcommonly it is used to cuttapered holes and other conical shapes
using a boring bar or lathe bits. There is a degree wheel directly underneath the
compound slide that can be set to the specific angle that is needed. There is no
“power feed” option and it must be operated manually.
8. Tailstock and its features.
The tailstock is located on the opposite end of the lathe from the chuck. It
is mounted on the ways of the machine and shares a centerline with the chuck.
The tail-stock’s most common use is to drill out the centers of work pieces. Into
the tailstock you can insert a drill chuck (that has a compatible “Jacobs Taper”).
The tailstock is slid toward the work piece and LOCKED DOWN, leaving about
1” of roombetween the drill and the work piece. The tailstock hand wheel is then
used to feed the drill into the work piece. Unlike other machines, the lathe work
piece spins and the cutting tool stays still.
The other commonuse is to supportlong work pieces (shafts / tubes / rods)
with the use of a live center. A live center is a cone shaped object with a Jacobs’s
taper adapter that is inserted into the tailstock (like a drill chuck). The cone
portion spins on an internal ball bearing mechanism. This is used to fit into a
center hole of the work piece to hold it firmly between the tailstock and chuck. It
is VERY important to lock down the tailstock and set correct tension with the
tailstock hand wheel whenever using the live center. This is done for pieces that
are too long to be safely held in just a chuck or collet. Normally, if the length of
piece is sticking out more than 5 times the diameter, a live center should be used.
For example, if the part is 1” in diameter, it should not stick out more than 5” in
length. Again, check with the shop supervisor for guidance! Live centers should
not be used when the work piece will be parted with a cut-off tool.
Drilling operation is carried out here. A large for the operation .To
complete the operation faster a few gauge milling machine are also provides.
Fig. 4 (c) DRILLING MACHINE
CENTER LATHE SECTION
Heavier lathes are provided in this section. All the lathes have four jaws
chuck for better holding centering is done either manually or with the help of
universal scriber. All kinds of turning are performed here. Parting off is other
major operation done.
Fig .4 (d) Centre lathe machine
The machine is also called horizontal shaping machine. It works on quick-return
mechanism .The arm of shaper reciprocating horizontally. The cutting take place only in the
forward stroke. The bed of the machine is fixed and the tool reciprocating. Shaping, Planning,
Grooving etc. are performed by this machine.
Fig .4 (d) Shaper machine
The is vertical shaping machine .The arm reciprocating in the vertical
direction .Mostparts are the same as shaper .Slotting is the process thatis carried
on this machine .
Fig .4(e) Slotter
The Work of this shop is to paint the coaches and bogie. In this shop there are
many sections and they are following –
1. COACH PAINTING.
2. LETTER SECTION.
3. TRIMMING SECTION.
4. CORROSION SECTION.
5. POLSIH SECTION.
PURPOSE OF PAINTING-
1. FOR PROTECTION AGAINST COROSION.
2. FOR DECORATION.
3. FOR COVERING.
MATERIAL USED IN PAINTING –
1. PAINT MATERIALS.
2. ENEMAL MATERIALS.
3. VARNISH MATERIALS.
4. LACQUER MATERIALS.
6. INERT OR FILLER MATERIAL.
Fig 5(a) Paint box
Fig 5.(b) Thinner
THE MAIN PROCESS INVOLVE IN PAINTING –
Firstly, Putin is prepared and it gets filled at the places where holes and
cracks has been found.
Secondly, the primer is put on the bodyand then finally painting is done in order
to give the body desire shape.
The overhauling of the coaches has been in given time interval it improves the
quality of coaches and it also prevents the coaches from break down. The
maintenance of coaches is according to time being is done as following-
1. MAIL EXPRESS- 12 MONTHS.
2. PASSENGER- 18 MONTHS.
3. NEWLY COACHES- 24 MONTHS.
TYPES OF PAINT
1. Aluminum Paint.
3. Asbestos paint.
4. Bituminous paint.
5. Cellule paint.
6. Cement paint.
8. Plastic paint.
A tool room is a room where tools are stored or, in a factory, a space
where tools are made and repaired for use throughout the rest of the factory. In
engineering and manufacturing, tool room activity is everything related to tool-
and-die facilities in contrast to production line activity.
Fig 6(a) Maintenance of tools
Making, repairing, and storing tools
The simplest sense of the word tool room implies merely storage. A broader use
of the term includes a space where tools are made, repaired, inventoried (kept
track of), and distributed for use throughout the rest of a factory. This extension
of sense reflects the development of greater systemization in manufacturing.
During the 19th century, there gradually developed the division of labour
whereby the people who made, repaired, kept records of, stored, and retrieved
tools were not necessarily the same people who used the tools to do the
manufacturing work itself. Examples of division of labour had existed in prior
centuries, but most manufacturing had been done on a craft basis, where there
had been no need for the idea of a tool room separate from the rest of the
workshop (or a word to name it).
The simplest sense above can also be conveyed by the word tool crib (sometimes
styled tool-crib or toolcrib). Although the word tool room is still sometimes used
todayin those simpler senses (and probablyalways will bebecauseofthe obvious
correspondence of word to literal meaning), mechanical engineers, toolmakers,
and other trained machinists usually use the word in its abstract tool-and-die
sense, which is discussed below. This restriction of sense is aided by using
another word (such as tool crib) to refer to the simpler, concrete senses.
Tool Room (TR) is the industrial set-up where the specialized tools, dies,
moulds, jigs, fixtures are designed and manufactured. These tools are used for
mass production. Many companies have their own captive TR or they assign the
work to the professionally managed TRs. The workflow starts in the ToolRoom
once it receives the Product Model or the Product Design / Drawing. Before
accepting the model, the TR professionals check the manufacturing feasibility of
the Tool for the product.
Fig 6 (b) Store the Tools in Tool Room
The mechanical maintenance department is responsible for the running of
DLW. It ensures that the all the machinery and equipment are running at their top
performance level without being affected by failure and breakdown. Working
with the engineers of the mechanical maintenance department I have gained such
an amount of knowledge which would not have been possible in a classroomin a
similar period time.
Also the practical experience I have gained here in DLW, VARANSI gave
me knowledge of to what extent my theoretical knowledge learnt in my college
is applicable in the field. Although the theoretical knowledge forms the base of
practical knowledge required onthe field , the field job also require somedifferent
set of skills which I learnt about during my training.
My skills in mechanical engineering has definitely been taken to a much
higher level than it was when I first joined the training program of 4 weeks back
and I truly consider myself highly fortunate to get this opportunity.