Industrial Visit Report to Shakurbasti and TRTC

16TH MAY 2012

Industrial Visits

Submitted to: Mr. Pradeep Khanna

Submitted By:

Rachit Goel

646/MP/10

Acknowledgement

I am overwhelmed in all humbleness and gratefulness to acknowledge all those

who have helped us to carry out the Industrial trip at the Diesel Engine

Locomotive Shed, Shakurbasti, and The Tool Research and Training Centre,

Wazirpur, well above the level of simplicity and into something concrete.

Any attempt at any level can't be satisfactorily completed without the support

and guidance of a teacher. I would like to express my immense gratitude to Mr.

Predeep Khanna for his time, effort and motivation provided through these

Industrial Visits that help in better understanding of the subject immensely.

TITLE PAGE NO.

1. Visit to Diesel Locomotive Shed, Shakurbasti

1.1 Details about the Shed

1.2 Diesel Locomotives

1.2.1 Working of a Diesel Engine Locomotive

1.2.2 The classification syntax

1.3 WDM 2 Locomotive

1.4 Parts of a Diesel Engine locomotive

1.5 Transmissions in a Diesel Engine Locomotive

1.5.1 mechanical Transmission

1.5.2 Hydraulic Transmission

1.5.3 Electric Transmission

1.6 Purpose of diesel Shed

1.7 Biodiesel plants

1.8 Non-destructive tests

1.8.1 Ultrasonic testing

1.8.2 Magnetic Flux Leakage

1.8.3 Liquid Penetrant Inspection

1.8.4 Zyglo Fluorescent Penetrant Test

2 The Tool Research and Training Centre, Wazirpur

2.1Introduction

2.2 CNC Milling

2.3 Types of milling machines

2.3.1 Knee type

2.3.2 Universal Milling Machine

2.3.3 Omniversal Milling Machine

2.3.4 Vertical Milling Machine

2.3.5 Copy Milling Machine

2.4 Grinding machine

2.5 Types of grinding operations

2.5.1 Surface Grinding

2.5.2 Cylindrical Grinding

2.5.3 Creep feed grinding

2.6 Types of grinders

2.6.1 Cylindrical Grinder

2.6.2 Surface Grinder

2.6.3 Jig Grinder

2.7 Electric Discharge Machine

2.7.1 Introduction

2.7.2 Applications

2.7.3 Advantages and Disadvantages of EDM

2.8 The lathe

2.9 Injection Moulding

2.10 Inspection Department

Visit to Diesel Locomotive Shed,

Shakurbasti

Details About the Diesel Shed It is the pioneer WDS4 Loco shed of Northern Railway and came into existence on 5th April, 1955. From its humble beginning in 1955, the Diesel Shed has evolved to become the premier shed for diesel-hydraulic locomotives over Indian Railways. Showing its commitment towards quality and environmental management, the Diesel Shed has acquired ISO 9001: 2000 and ISO 4001:1996 certifications. This shed has also been entrusted with the maintenance of 140T Gottwald Cranes (Break-down Cranes). This shed is also earning by rendering engineering services to public sector undertakings having 37 locos since 1979 and carrying out all major schedules upto periodic overhauling with total satisfaction of customers. Total Shed Area = 41141 SQM. Total Covered Area =15417 SQM. Total Staff Employed = 800 approx. Total Capacity for WDS 4 = 108

Diesel locomotives A locomotive is a railway vehicle that provides the motive power for a train. The word originates from the Latin loco - "from a place", Latin motivus, "causing motion". A Diesel locomotive is a type of railroad locomotive in which the prime mover is a Diesel engine.

Working of A Diesel Locomotive Engine

The Engine

Diesel locomotives are classified on the basis of the track Gauge over which they are designed to run.

1) Broad Gauge 2) Meter gauge 3) Narrow gauge

All the diesel locomotive repaired and looked after in Shakurbasti diesel shed are of Broad gauge type. These broad gauge locos can also be classified on the basis of purpose of use.

1) Passenger Locos 2) Goods Locos 3) Mixed type Locos 4) Shunting Locos or switching locos.

Passenger Locos : These are ones which are used to carry passenger from one place to another. They include WDP 1 WDP 2 WDP 3 WDP 4.

Goods locos : They are used for carrying goods. These include WDG 2 WDG 3B, WDG 3C, WDG 3D and WDG4.

Mixed Locos : They carry both Goods and locos. They Include WDM 1,WDM 2, WDM 2A, WDM 2B, WDM 3, WDM 3A, WDM 3C, WDM 3D,

WDM 4, WDM 6, WDM 7.

Shunting locos: They are used for shunting purposes. They include WDS 1, WDS 2, WDS3, WDS4, WDS 4A, WDS4B, WDS 4C, WDS4D, WDS 5, WDS 6, WDS 8.

Along with these there are also Diesel Multiple units : DEMU and DHMU Of All these ShakurBasti loco plant takes care of only :

1. WDM 2 2. WDS 4 3. BG DEMU (Broad gauge DEMU) 4. MG DEMU (Meter gauge DEMU)

The Classification Syntaxes

Locos have classification codes that identify them. This code is of the form [gauge] [power] [load] [series]

In this the first item, '[gauge]', is a single letter identifying the gauge the loco runs on:

W = Broad Gauge Y = Meter Gauge Z = Narrow Gauge (2' 6") N = Narrow Gauge (2')

The second item, '[power]', is one or two letters identifying the power source:

D = Diesel C = DC traction A = AC traction CA = Dual-power AC/DC traction B = Battery electric(rare)

The third item, '[load]', is a single letter identifying the kind of load the loco is normally used for:

M = Mixed Traffic P = Passenger G = Goods S = Shunting L = Light Duty (Light Passenger) U = Multiple Unit (EMU / DEMU)

The fourth item, '[series]', is a digit identifying the model of the loco. Until recently, this series number was simply assigned chronologically as new models of locos were introduced.

With this WDM2 corresponds to : W = Broad Gauge D = Diesel M = Mixed Traffic 2 = This is a series no. On the similar basis we can identify different diesel engines.

WDM 2 Locomotive The WDM-2 is the most common diesel locomotive of Indian Railways. The class WDM-2 is Indian Railways' workhorse diesel locomotive. The first units were imported fully built from the American Locomotive Company (Alco) in 1962. Since 1964, it has been manufactured in India by the Diesel Locomotive Works (DLW), Varanasi. This is the first Homemade Diesel-electric Locomotive (DEL). WDM2 is designed for mixed traffic service, passenger and freight. The loco equipped with fully equalized trimount trucks has medium axle loading and higher adhesion. WDM2 has characteristics of low and easy maintenance, reduced noise and exhaust emissions, fuel saving, safe and comfortable riding and reliable high performance.

The WDM-2A is a variant of the original WDM-2. These units have been retro-fitted with air brakes, in addition to the original vacuum brakes. The WDM-2B is a more recent locomotive, built with air brakes as original equipment.

Technical specifications :

Builders: Alco, DLW

Engine: Alco 251-B, 16 cylinder, 2600hp (2430hp site rating) with Alco 710/720/?? turbocharger. 1000rpm max, 400rpm idle; 228mm x 266mm bore/stroke; compression ratio 12.5:1. Direct fuel injection, centrifugal pump cooling system (2457l/min @ 1000rpm), fan driven by eddy current clutch (86hp @ engine rpm 1000).

Governor: GE 17MG8 / Woodwards 8574-650.

Transmission: Electric, with BHEL TG 10931 AZ generator (1000rpm, 770V, 4520A).

Traction motors: GE752 (original Alco models) (405hp), BHEL 4906 BZ (AZ?) (435hp) and (newer) 4907 AZ (with roller bearings)

Axle Load: 18.8 tonnes, total weight 112.8t.

Bogies: Alco design asymmetric cast frame trimount (Co-Co) bogies (shared with WDS-6, WDM-7, WAM-4, WCAM-1, WCG-2).

Starting TE: 30.4t, at adhesion 27%.

Length over buffer beams: 15862mm.

Distance between bogies: 10516mm.

Parts of a Diesel-Electric Locomotive The following diagram shows the main parts of a US-built diesel-electric locomotive. Click on the part name for a description.

Diesel Engine

This is the main power source for the locomotive. It comprises a large cylinder block, with the cylinders arranged in a straight line or in a V (see more here). The engine rotates the drive shaft at up to 1,000 rpm and this drives the various items needed to power the locomotive. As the transmission is electric, the engine is used as the power source for the electricity generator or alternator, as it is called nowadays.

Main Alternator

The diesel engine drives the main alternator which provides the power to move the train. The alternator generates AC electricity which is used to provide power for the traction motors mounted on the trucks (bogies). In older locomotives, the alternator was a DC machine, called a generator. It produced direct current which was used to provide power for DC traction motors. Many of these machines are still in regular use. The next development was the replacement of the generator by the alternator but still using DC traction motors. The AC output is rectified to give the DC required for the motors.

Auxiliary Alternator

Locomotives used to operate passenger trains are equipped with an auxiliary alternator. This provides AC power for lighting, heating, air conditioning, dining facilities etc. on the train. The output is transmitted along the train through an auxiliary power line. In the US, it is known as "head end power" or

"hotel power". In the UK, air conditioned passenger coaches get what is called electric train supply (ETS) from the auxiliary alternator.

Air Intakes

The air for cooling the locomotive's motors is drawn in from outside the locomotive. It has to be filtered to remove dust and other impurities and its flow regulated by temperature, both inside and outside the locomotive. The air management system has to take account of the wide range of temperatures from the possible +40°C of summer to the possible -40°C of winter.

Electronic Controls

Almost every part of the modern locomotive's equipment has some form of electronic control. These are usually collected in a control cubicle near the cab for easy access. The controls will usually include a maintenance management system of some sort which can be used to download data to a portable or hand-held computer.

Batteries

Just like an automobile, the diesel engine needs a battery to start it and to provide electrical power for lights and controls when the engine is switched off and the alternator is not running.

Traction Motor

Since the diesel-electric locomotive uses electric transmission, traction motors are provided on the axles to give the final drive. These motors were traditionally DC but the development of modern power and control electronics has led to the introduction of 3-phase AC motors. For a description of how this technology works, go to the Electronic Power Page on this site. There are between four and six motors on most diesel-electric locomotives. A modern AC motor with air blowing can provide up to 1,000 hp.

Pinion/Gear

The traction motor drives the axle through a reduction gear of a range between 3 to 1 (freight) and 4 to 1 (passenger).

Fuel Tank

A diesel locomotive has to carry its own fuel around with it and there has to be enough for a reasonable length of trip. The fuel tank is normally under the loco frame and will have a capacity of say 1,000 imperial gallons (UK Class 59, 3,000 hp) or 5,000 US gallons in a General Electric AC4400CW 4,400 hp

locomotive. The new AC6000s have 5,500 gallon tanks. In addition to fuel, the locomotive will carry around, typically about 300 US gallons of cooling water and 250 gallons of lubricating oil for the diesel engine.

Air Reservoirs

Air reservoirs containing compressed air at high pressure are required for the

train braking and some other systems on the locomotive. These are often

mounted next to the fuel tank under the floor of the locomotive.

Air Compressor

The air compressor is required to provide a constant supply of compressed air for the locomotive and train brakes. In the US, it is standard practice to drive the compressor off the diesel engine drive shaft. In the UK, the compressor is usually electrically driven and can therefore be mounted anywhere. The Class 60 compressor is under the frame, whereas the Class 37 has the compressors in the nose.

Drive Shaft

The main output from the diesel engine is transmitted by the drive shaft to the alternators at one end and the radiator fans and compressor at the other end.

Gear Box

The radiator and its cooling fan is often located in the roof of the locomotive. Drive to the fan is therefore through a gearbox to change the direction of the drive upwards.

Radiator and Radiator Fan

The radiator works the same way as in an automobile. Water is distributed around the engine block to keep the temperature within the most efficient range for the engine. The water is cooled by passing it through a radiator blown by a fan driven by the diesel engine. See Cooling for more information.

Turbo Charging

The amount of power obtained from a cylinder in a diesel engine depends on how much fuel can be burnt in it. The amount of fuel which can be burnt depends on the amount of air available in the cylinder. So, if you can get more air into the cylinder, more fuel will be burnt and you will get more power out of your ignition. Turbo charging is used to increase the amount of air pushed into each cylinder. The turbocharger is driven by exhaust gas from the engine. This

gas drives a fan which, in turn, drives a small compressor which pushes the additional air into the cylinder. Turbocharging gives a 50% increase in engine power.

The main advantage of the turbocharger is that it gives more power with no increase in fuel costs because it uses exhaust gas as drive power. It does need additional maintenance, however, so there are some type of lower power locomotives which are built without it.

Sand Box

Locomotives always carry sand to assist adhesion in bad rail conditions. Sand is not often provided on multiple unit trains because the adhesion requirements are lower and there are normally more driven axles.

Truck Frame

This is the part (called the bogie in the UK) carrying the wheels and traction motors of the locomotive. More information is available at theBogie Parts Page or the Wheels and Bogies Page on this site.

Braking in a Diesel Engine Locomotive Dynamic Braking : Dynamic braking takes advantage of the fact that the traction motor

armatures are always rotating when the locomotive is in motion and that a

motor can be made to act as a generator by separately exciting the field

winding. When dynamic braking is utilized, the traction control circuits are

configured as follows:

The field winding of each traction motor is connected across the main

generator (MG). The armature of each traction motor is connected across a forced-air

cooled resistance grid (the dynamic braking grid) in the roof of the locomotive's hood.

The prime mover RPM is increased and the MG field is excited, causing a corresponding excitation of the traction motor fields.

The aggregate effect of the above is to cause each traction motor to generate electric power and dissipate it as heat in the dynamic braking grid. Forced air-cooling is provided by a fan that is connected across the grid. Consequently, the fan is powered by the output of the traction motors and will tend to run faster and produce more airflow as more energy is applied to the grid. Ultimately, the source of the energy dissipated in the dynamic braking grid is

the motion of the locomotive as imparted to the traction motor armatures.

Therefore, the traction motors impose drag and the locomotive acts as a

brake.

Air Brakes : An air brake is a conveyance braking system applied by means of compressed air.

In the air brake's simplest form, called the straight air system,

compressed air pushes on a piston in a cylinder. The piston is connected through mechanical linkage to brake shoes that can rub on the train wheels, using the resulting friction to slow the train. The mechanical linkage can become quite elaborate, as it evenly distributes force from one pressurized air cylinder to 8 or 12 wheels.

The pressurized air comes from an air compressor in the locomotive and is

sent from car to car by a train line made up of pipes beneath each car and

hoses between cars.

Modern air brake systems are in effect two braking systems combined:

1. The service brake system, which applies and releases the brakes

during normal operations, and

2. The emergency brake system, which applies the brakes rapidly in the

event of a brake pipe failure or an emergency application by the

engineer.

TRANSMISSIONS IN A DIESEL ENGINE LOCOMOTIVE

Mechanical Transmission A diesel-mechanical locomotive is the simplest type of diesel locomotive. As the name suggests, a mechanical transmission on a diesel locomotive consists a direct mechanical link between the diesel engine and the wheels. In the example below, the diesel engine is in the 350-500 hp range and the transmission is similar to that of an automobile with a four speed gearbox. Most of the parts are similar to the diesel-electric locomotive but there are some variations in design mentioned below.

Fluid Coupling

In a diesel-mechanical transmission, the main drive shaft is coupled to the engine by a fluid coupling. This is a hydraulic clutch, consisting of a case filled with oil, a rotating disc with curved blades driven by the engine and another connected to the road wheels. As the engine turns the fan, the oil is driven by one disc towards the other. This turns under the force of the oil and thus turns the drive shaft. Of course, the start up is gradual until the fan speed is almost

matched by the blades. The whole system acts like an automatic clutch to allow a graduated start for the locomotive.

Gearbox

This does the same job as that on an automobile. It varies the gear ratio between the engine and the road wheels so that the appropriate level of power can be applied to the wheels. Gear change is manual. There is no need for a separate clutch because the functions of a clutch are already provided in the fluid coupling.

Final Drive

The diesel-mechanical locomotive uses a final drive similar to that of a steam engine. The wheels are coupled to each other to provide more adhesion. The output from the 4-speed gearbox is coupled to a final drive and reversing gearbox which is provided with a transverse drive shaft and balance weights. This is connected to the driving wheels by connecting rods

Diesel – hydraulic Transmission : Hydraulic transmission works on the same principal as the fluid coupling but it allows a wider range of "slip" between the engine and wheels. It is known as a "torque converter". When the train speed has increased sufficiently to match the engine speed, the fluid is drained out of the torque converter so that the engine is virtually coupled directly to the locomotive wheels. It is virtually direct because the coupling is usually a fluid coupling, to give some "slip". Higher speed locomotives use two or three torque converters in a sequence similar to gear changing in a mechanical transmission and some have used a combination of torque converters and gears.

Wheel Slip

Wheels slip is the bane of the driver trying to get a train away smoothly. The tenuous contact between steel wheel and steel rail is one of the weakest parts of the railway system. Traditionally, the only cure has been a combination of the skill of the driver and the selective use of sand to improve the adhesion. Today, modern electronic control has produced a very effective answer to this age old problem. The system is called creep control.

Extensive research into wheel slip showed that, even after a wheelset starts to slip, there is still a considerable amount of useable adhesion available for

traction. The adhesion is available up to a peak, when it will rapidly fall away to an uncontrolled spin. Monitoring the early stages of slip can be used to adjust the power being applied to the wheels so that the adhesion is kept within the limits of the "creep" towards the peak level before the uncontrolled spin sets in.

The slip is measured by detecting the locomotive speed by Doppler radar (instead of the usual method using the rotating wheels) and comparing it to the motor current to see if the wheel rotation matches the ground speed. If there is a disparity between the two, the motor current is adjusted to keep the slip within the "creep" range and keep the tractive effort at the maximum level possible under the creep conditions.

Diesel Electric Transmission :

Diesel-Electric Types

Diesel-electric locomotives come in three varieties, according to the period in which they were designed. These three are:

DC - DC (DC generator supplying DC traction motors); AC - DC (AC alternator output rectified to supply DC motors) and AC - DC - AC (AC alternator output rectified to DC and then inverted to 3-phase AC for the traction motors). The DC - DC type has a generator supplying the DC traction motors through a resistance control system, the AC - DC type has an alternator producing AC current which is rectified to DC and then supplied to the DC traction motors and, finally, the most modern has the AC alternator output being rectified to DC and then converted to AC (3-phase) so that it can power the 3-phase AC traction motors. Although this last system might seem the most complex, the gains from using AC motors far outweigh the apparent complexity of the system. In reality, most of the equipment uses solid state power electronics with microprocessor-based controls.

There is one traction alternator (or generator) per diesel engine in a locomotive (standard North American practice anyway). The Alco C628 was the last locomotive to lead the horsepower race with a DC traction alternator.

Purpose of Diesel Shed The Shakurbasti diesel shed was constructed for repair and maintenance of diesel locos. They follow a strict plan for maintenance of the locos. Every loco has a specific time after which it has return to the Shed for testing and other repairs. Diesel Shed also include a Workshop in which different components of loco are machined or repaired The basic things they inspect upon are :

Fuel Tanks

Wheels and Axles

Brake System

Trucks

Wheels and Axles

Speed Indicators

Different Level Switches

Audible Signals

Illuminating Devices

Basic Engine components

Turbocharger

Radiators

Filters

Batteries

Cab etc.

BIODIESEL PLANT

BIO-DIESEL PROCESSING UNIT IS CONSISIT OF FOLLOWING UNITS The seed crushers manufactured by us are used widely in the agro industries for crushing of Jatropha and other oil seeds. These machines are highly advanced and are used for crushing the kernels extracted out from the decorticating machine. We have equipped this machine with a steam bath unit for pre-operation of the kernels and filtration unit for purifying the extracted crude oil. The oil cake left behind after purification is used for the agricultural purposes as manure or raw material for the bio gas plant. We also offer customized seed crushers to our clients. Features: • Capacity – 50 Kg / hr. onwards • Fuel - Electricity • Power Req – 10 hp onwards Transesterification Unit > The product obtained by trans-esterification of any vegetable oil is said to be bio diesel. Biodiesel is defined as the mono alkyl esters of long chain fatty acids derived from renewable lipid sources. Biodiesel is typically produced through the reaction of a vegetable oil or animal fat with methanol in the presence of a catalyst to yield glycerin and biodiesel (chemically called methyl esters). Biodiesel is an alternative fuel, which can be used in neat form, or blended with petroleum diesel for use in compression ignition (diesel) engines. Its physical and chemical properties as it relates to operation of diesel engines are similar to petroleum based diesel fuel. We possess an unmatched expertise in offering highly advanced and innovative trans-esterification unit to our clients. These units find diverse applications in the agro industries related to the processing and extraction of bio-diesel. These units efficiently produce high outputs of bio-diesel used in the commercial market as an automobile fuel. All the processes of these machines are highly sophisticated and PLC BASED controll. The by-products left over by this unit after the extraction of pure diesel like glycerol is also marketable. We can offer these units in various capacities as per the specified requirements of our clients

Bio Diesel Benefits: 1. Greatest reduction in emission. 2. Higher lubricity. 3. Biodegradable- 95% degradation in 28 days, whereas diesel fuel degrades 40% in 28 days. 4. Non-toxicity. 5. Decreased Global warming. 6. Positive impact on agriculture. The biodiesel can be manufactured from Crude Palm Oil. The other oil sources are all the non-edible oils, a few of them are Jatropha oil, Neem Oil, Karanja Oil, Mahua Oil, etc. Also used frying (cooking) oils can be used for bio diesel production.

Biodiesel Compared to Petroleum Diesel

Advantages Disadvantages

Domestically produced from non-

petroluem, renewable resources

Can be used in most diesel engines,

especially newer ones

Less air pollutants (other than

nitrogen oxides) and greenhouse

gases

Biodegradable

Non-toxic

Safer to handle

Use of blends above B5 not yet

warrantied by auto makers

Lower fuel economy and power

(10% lower for B100, 2% for B20)

Currently more expensive

More nitrogen oxide emissions

B100 generally not suitable for use

in low temperatures

Concerns about B100's impact on

engine durability

NON DESTRUCTIVE TESTING Introduction Nondestructive testing or Non-destructive testing (NDT) is a wide group of

analysis techniques used in science and industry to evaluate the properties of a

material, component or system without causing damage.[1] The

terms Nondestructive examination (NDE), Nondestructive inspection (NDI),

and Nondestructive evaluation (NDE) are also commonly used to describe this

technology.[2] Because NDT does not permanently alter the article being

inspected, it is a highly-valuable technique that can save both money and time

in product evaluation, troubleshooting, and research. Common NDT methods

include ultrasonic, magnetic-particle, liquid penetrant, radiographic, remote

visual inspection (RVI), eddy-current testing, and low coherence interferometry

NDT methods may rely upon use of electromagnetic radiation, sound, and inherent properties of materials to examine samples. This includes some kinds of microscopy to examine external surfaces in detail, although sample preparation techniques for metallography, optical microscopy and electron microscopy are generally destructive as the surfaces must be made smooth through polishing or the sample must be electron transparent in thickness. The inside of a sample can be examined with penetrating electromagnetic radiation, such as X-rays or 3D X-rays for volumetric inspection. Sound waves are utilized in the case of ultrasonic testing. Contrast between a defect and the bulk of the sample may be enhanced for visual examination by the unaided eye by using liquids to penetrate fatigue cracks. One method (liquid penetrant testing) involves using dyes, fluorescent or non-fluorescing, in fluids for non-magnetic materials, usually metals. Another commonly used method for magnetic materials involves using a liquid suspension of fine iron particles applied to a part while it is in an externally applied magnetic field (magnetic-particle testing).Thermoelectric effect (or use of the Seebeck effect) uses thermal properties of an alloy to quickly and easily characterize many alloys. The chemical test, or chemical spot test method, utilizes application of sensitive chemicals that can indicate the presence of individual alloying elements.

Basically 4 Non destructive tests are employed in the Diesel Shed.

1) In Ultrasonic testing, very short ultrasonic pulse-waves with center

frequencies ranging from 0.1-15 MHz and occasionally up to 50 MHz are launched into materials to detect internal flaws or to characterize materials. Ultrasonic testing is often performed on steel and other metals and alloys, though it can also be used on concrete, wood and composites, albeit with less resolution. It is a form of non-destructive testing used in many industries includingaerospace, automotive and other transportation sectors

2) Magnetic flux leakage (MFL) is a magnetic method of

nondestructive testing that is used to detect corrosion and pitting in steel structures, most commonly pipelines and storage tanks. The basic principle is that a powerful magnet is used to magnetize the steel. At areas where there is corrosion or missing metal, the magnetic field "leaks" from the steel. In an MFL tool, a magnetic detector is placed between the poles of the magnet to detect the leakage field. Analysts interpret the chart recording of the leakage field to identify damaged areas and hopefully to estimate the depth of metal loss. This article currently focuses mainly on the pipeline application of MFL, but links to tank floor examination are provided at the end.

3) Liquid penetrant inspection (LPI), is a widely applied and low-cost

inspection method used to locate surface-breaking defects in all non-porous materials (metals, plastics, or ceramics). Penetrant may be applied to all non-ferrous materials, but for inspection of ferrous components magnetic-particle inspection is preferred for its subsurface detection capability. LPI is used to detect casting and forging defects, cracks, and leaks in new products, and fatigue cracks on in-service components.

When used with a Red die it is known as Red Die Penetrant

Inspection. Red dye penetrants are visible under normal light.

4) Zyglo Fluorescent Penetrant Test The ZYGLO® fluorescent

Penetrant process is a nondestructive testing (NDT) method that helps you locate and identify surface defects in order to screen out potential failure-producing defects, correct production problems and increase product uniformity. It is a quick and accurate process for locating surface flaws such as shrinkage cracks, porosity, cold shuts, fatigue cracks, grinding cracks, heat treat cracks, seams, forging laps, forging bursts, through leaks, and lack of bond.

The Tool Research and Training

Centre, Wazirpur

INTRODUCTION The Tool Room Training Centre (TRTC) is situated in the Wazirpur Industrial

Area Covering an area of approximately 3.5 Acres.

They started with short term courses but now have expanded to a larger

extent. They guarantee 100% placements through college. In today’s date the

courses include: short term courses, CADCAM, Advanced-Working in tool room

(highly skilled). Courses may be fortnightly, monthly or yearly. i.e.

1. Design & Manufacture of Tools & Dies, Gauges, Jigs & Fixtures 2. Undertaking Project Assignment 3. Free Consultancy in the field of Product Development, Product

Manufacturing, Tooling & Setting of projects 4. Processing of Plastic & Sheet metal Components 5. Training of Tool Designers, Tool Makers, Tool Room Machine Operator &

Tool Fitters 6. Providing training on CAD/CAM & Computer Application

Tool Room & Training Centre, Delhi was established in 1976 with Technical and

Financial Assistance of Govt. of Denmark with Govt. of Delhi. In short span of

two decades the Centre has emerged a pioneer in its efforts to create an

indigenous technical base suitable to the industry. The Centre concentrate on

two vital fields i.e. Training of Technical hands & Manufactures of sophisticated

Tools and in each tangible results have been achieved by the Centre.

They are in the process of changing their name to DITE (Delhi Institute of

Technical Engineering) in the year 2008.

TRTC is divided into two Departments viz. Training and Production

departments. They have CNC and other specialized machines for training.

At the starting we were given an introduction of the different courses offered

for M-Tech ( 2 years AUTOCAD) and for Training (4 years for Post Graduate for

tool design and 1 year Advanced course for ITI students). Short term courses

included Tool Making and Mould Making.

CNC Milling

A Computer Numerical Control (CNC) milling machine was shown to us. Numerical control (NC) refers to the automation of machine tools that are operated by abstractly programmed commands encoded on a storage medium, as opposed to manually controlled via handwheels or levers, or mechanically automated via cams alone. The first NC machines were built in the 1940s and '50s, based on existing tools that were modified with motors that moved the controls to follow points fed into the system on paper tape. These early servomechanisms were rapidly augmented with analog and digital computers, creating the modern computed numerically controlled (CNC) machine tools that have revolutionized the design process.

In modern CNC systems, end-to-end component design is highly automated using programs. The programs produce a computer file that is interpreted to extract the commands needed to operate a particular machine via a post processor, and then loaded into the CNC machines for production. Since any particular component might require the use of a number of different tools—drills, saws, etc.—modern machines often combine multiple tools into a single "cell". In other cases, a number of different machines are used with an external controller and human or robotic operators that move the component from machine to machine. In either case, the complex series of steps needed to produce any part is highly automated and produces a part that closely matches the original CAD design.

CNC mills can perform the functions of drilling and often turning. CNC Mills are classified according to the number of axes that they possess. Axes are labeled as x and y for horizontal movement, and z for vertical movement, as shown in this view of a manual mill table. A standard manual light-duty mill is typically assumed to have four axes:

1. Table x. 2. Table y. 3. Table z. 4. Milling Head z.

CNC machines can exist in virtually any of the forms of manual machinery, like horizontal mills. The most advanced CNC milling-machines, the 5-axis machines, add two more axes in addition to the three normal axes (XYZ). Horizontal milling machines also have a C or Q axis, allowing the horizontally mounted workpiece to be rotated, essentially allowing asymmetric and eccentric turning. The fifth axis (B axis) controls the tilt of the tool itself. When all of these axes are used in conjunction with each other, extremely complicated geometries, even organic geometries such as a human head can be made with relative ease with these machines. But the skill to program such geometries is beyond that of most operators. Therefore, 5-axis milling machines are practically always programmed with CAM.

TYPES OF MILLING MACHINES

1) Knee Type

Knee-type mills are characterized by a vertically adjustable worktable resting on a saddle which is supported by a knee. The knee is a massive casting that rides vertically on the milling machine column and can be clamped rigidly to the column in a position where the milling head and milling machine spindle are properly adjusted vertically for operation.

The plain vertical machines are characterized by a spindle located vertically, parallel to the column face, and mounted in a sliding head that can be fed up and down by hand or power. Modern vertical milling machines are designed so the entire head can also swivel to permit working on angular surfaces.

The turret and swivel head assembly is designed for making precision cuts and can be swung 360° on its base. Angular cuts to the horizontal plane may be made with precision by setting the head at any required angle within a 180° arc.

2) Universal Milling Machine

The basic difference between a universal horizontal milling machine and a plain horizontal milling machine is the addition of swivel housing between the table and the saddle of the universal machine. This permits the table to swing up to 45° in either direction for angular and helical milling operations. The universal machine can be fitted with various attachments such as the indexing fixture, rotary

3) Omniversal Milling Machine

In omniversal milling machine table has all movements of universal milling

machine but can also be tilted about vertical plane by providing a swivlling

arrangement at knee. The additional swivlling arrangement enables it to cut

taper helical groves in bevel gears and reamers etc.

4) Vertical Milling Machine

In vertical milling machine axis of cutter is perpendicular to the job.

5) Copy Milling Machine

It is a manually operated machine tool by which exactly same copy of a

workpiece can be cut by the cutters. It has a specially designed arm which

works on trigonometric ratios. The cutter attached to one part of the arm

copies the movement of the pointer on the workpiece to be traced and cuts

the same shape. Vibrations are produced, therefore operation requires

experienced operator. Arms can be adjusted for giving different ratios like 1:1,

1:2, 1:3, etc.

GRINDING MACHINE

The grinding machine consists of a power driven grinding wheel spinning at the required speed (which is determined by the wheel’s diameter and manufacturer’s rating, usually by a formula) and a bed with a fixture to guide and hold the work-piece. The grinding head can be controlled to travel across a fixed work piece or the workpiece can be moved whilst the grind head stays in a fixed position. Very fine control of the grinding head or tables position is possible using a vernier calibrated hand wheel, or using the features of numerical controls.

Grinding machines remove material from the workpiece by abrasion, which can generate substantial amounts of heat; they therefore incorporate a coolant to cool the workpiece so that it does not overheat and go outside its tolerance. The coolant also benefits the machinist as the heat generated may cause burns in some cases.

The machine is basically a type of maching using an wheel as the cutting tool.

Each grain of abrasive on the wheel's surface cuts a small chip from the

workpiece via shear deformation.

TYPES OF GRINDING OPERATIONS

1) Surface grinding

Surface grinding uses a rotating abrasive wheel to smooth the flat surface of

metallic or nonmetallic materials to give them a more refined look or to attain

a desired surface for a functional purpose. The tolerances that are normally

achieved with grinding are ± 2 × 10−4inches for a grinding a flat material, and ±

3 × 10−4inches for a parallel surface. (in metric units : 5 um for flat material and

8 um for parallel surface).

The surface grinder is composed of an abrasive wheel, a workholding device known as a chuck, either electromagnetic or vacuum, and a reciprocating table.

2) Cylindrical grinding

Cylindrical grinding (also called center-type grinding) is used in the removing the cylindrical surfaces and shoulders of the workpiece. The workpiece is mounted and rotated by a workpiece holder, also known as a grinding dog or center driver. Both the tool and the workpiece are rotated by separate motors and at different speeds. The axes of rotation tool can be adjusted to produce a variety of shapes.

The five types of cylindrical grinding are: outside diameter (OD) grinding, inside diameter (ID) grinding, plunge grinding, creep feed grinding, and centerless grinding.[1].

3) Creep-feed grinding

Creep-feed grinding (CFG) was invented in Germany in the late 1950s by Edmund and Gerhard Lang. Unlike normal grinding, which is used primarily to finish surfaces, CFG is used for high rates of material removal, competing with milling and turning as a manufacturing process choice. Depths of cut of up to 6 mm (0.25 inches) are used along with low workpiece speed. Surfaces with a softer-grade resin bond are used to keep workpiece temperature low and an improved surface finish up to 1.6 micrometres Rmax

With CFG it takes 117 sec to remove 1 in.3 of material, whereas precision grinding would take more than 200 sec to do the same. CFG has the

disadvantage of a wheel that is constantly degrading, and requires high spindle power, 51 hp (38 kW), and is limited in the length of part it can machine.

Types of grinders

These machines were shown to us..

Cylindrical grinder which includes the centerless grinder. A cylindrical grinder may have multiple grinding wheels. The workpiece is rotated and fed past the wheel/s to form a cylinder. It is used to make precision rods

Cylindrical grinder

Surface grinder which includes the wash grinder. A surface grinder has a "head" which is lowered, and the workpiece is moved back and forth past the grinding wheel on a table that has a permanent magnet for use with magnetic stock. Surface grinders can be manually operated or have CNC controls

Surface Grinder

Jig grinder, which as the name implies, has a variety of uses when finishing jigs, dies, and fixtures. Its primary function is in the realm of grinding holes and pins. It can also be used for complex surface grinding to finish work started on a mill

Jig grinder

Electric discharge machining (EDM)

INTRODUCTION

EDM refers to Electrical Discharge Machining. The complex shapes which cannot be made using conventional machines are made by electrodes. Basically EDM is a machining method primarily used for hard metals or those that would be impossible to machine with traditional techniques.Sometimes referred to as spark machining or spark eroding, EDM is a nontraditional method of removing material by a series of rapidly recurring electric arcing discharges between an electrode (the cutting tool) and the workpiece, in the presence of an energetic electric field.

We were shown some complex shapes made by EDM that could have been really difficult to make otherwise. Female or even Male parts of certain couplings may be sometimes difficult to make due to reduced accessibility.Graphite or Copper may be used for making the electrodes. Conventionally Hardened steels are difficult to machine, but EDM can even machine H.S very easily.

The EDM cutting tool is guided along the desired path very close to the work but it does not touch the piece. An arc is created due to the high voltage, due to which the material of the work piece gets eroded away and thus a profile of the electrode is created on it gradually. Consecutive sparks produce a series of micro-craters on the work piece and remove material along the cutting path by melting and vaporization. The particles are washed away by the continuously flushing dielectric fluid (kerosene is used as dielectric). The dielectric fluid also helps in the conduction of the discharge from the electrode to the work piece. Water is best for this purpose but not used due to its corroding property.

The electrode is made negative and the work piece as positive during the whole process.It is a gradual process and is

Figure 1 : EDM cutting

automatically switched off when whole impression is transferred. A micrometer is used for this purpose. As the process continues, the micrometer moves downward ( very slowly ), and when it reaches the bottom the machine automatically switches off.

In this process, the current values should be adjusted accurately. Too high current does finishes the work in short duration but reduces the surface finish. So current is generally reduced so as to obtain a finely finished job.

Applications

1) Prototype production

The EDM process is most widely used by the mould-making tool and die

industries, but is becoming a common method of making prototype and

production parts, especially in the aerospace, automobile and electronics

industries in which production quantities are relatively low. In Sinker EDM, a

graphite, copper tungsten or pure copper electrode is machined into the

desired (negative) shape and fed into the workpiece on the end of a vertical

ram.

2)Coinage die making

For the creation of dies for producing jewelry and badges by the coinage

(stamping) process, the positive master may be made from sterling silver, since

(with appropriate machine settings) the master is not significantly eroded and

is used only once. The resultant negative die is then hardened and used in a

drop hammer to produce stamped flats from cutout sheet blanks of bronze,

silver, or low proof gold alloy. For badges these flats may be further shaped to

a curved surface by another die. This type of EDM is usually performed

submerged in an oil-based dielectric. The finished object may be further

refined by hard (glass) or soft (paint) enameling and/or electroplated with pure

gold or nickel. Softer materials such as silver may be hand engraved as a

refinement

EDM control panel (Hansvedt machine). Machine may be adjusted for a refined

surface (electropolish) at end of process.

Master at top, badge die workpiece at bottom, oil jets at left (oil has been

drained). Initial flat stamping will be "dapped" to give a curved surface.

Advantages of EDM:

1. Machining of complex shapes that would otherwise be difficult to

produce with conventional cutting tools

2. extremely hard material can be machined to very close tolerances

3. very small work pieces can be machined where conventional cutting

tools may damage the part from excess cutting tool pressure.

Disadvantages of EDM:

1. inability to machine non conductive materials

2. slow rate of material removal

3. additional time and cost used for creating electrodes

The Lathe

A lathe is a machine tool which spins a block of material to perform various operations such as facing, turning, centre drilling, tapered turning, step turning, eccentric turning, grooving, form turning, external threading, knurling, parting off, chamfering, drilling, reaming, boring, internal thread cutting, trepanning, filing, spring winding, counter boring, counter sunking and undercutting using a single point cutting tool. There are basically different work holding arrangements in a lathe. The lathe shown to us had a simple three jaw chuck fitted onto its spindle. The chucks may be three jaw chuck, four jaw chuck, collet chuck, pneumatic chucks, magnetic chucks etc. Longer work pieces in a lathe, are held between centres. Centres may be a normal centre, revolving centre, tipped centre, half centre, ball centre, self driving centre or a female centre. These centres may hold the workpiece but are not able to transmit power from the spindle to the workpiece. For this purpose, Dogs are used. Mandrels play a very important role. They are basically used to keep the workpiece centred during all the operations carried on it. Suppose blanking operation has been done on a job, and it has to be taken to a milling machine for further gear cutting operation.

INJECTION MOULDING

It is a manufacturing technique for making parts from thermoplastic and

thermosetting plastic in production. Injection molding is accomplished by large

machines called injection molding machines. Molten plastic is injected at high

pressure into a mould which is the inverse of the product’s shape.

Resin enters the barrel through the hopper as shown in the figure. Colorants

are added through the hopper itself just after the addition of resin. Resin is

then heated to an appropriate melting temperature. Resin enters the mold by

a reciprocating screw or a ram injector. Its reciprocating screw mechanism is

shown below

The reciprocating screw offers the advantage of being able to inject a smaller

percentage of the total shot (amount of melted resin in the barrel). The ram

injector must typically inject at least 20% of the total shot while a screw

injector can inject as little as 5% of the total shot. Essentially, the screw

injector is better suited for producing smaller parts.

The mold is the part of the machine that receives the plastic and shapes it

appropriately. The mold is cooled constantly to a temperature that allows the

resin to solidify and be cool to the touch. The mold plates are held together by

hydraulic or mechanical force

INSPECTION DEPARTMENT

This section at TRTC was utilized for checking the finished jobs and then

machining them as per requirement. For this purpose a Profile Projector is

used.

Magnification can be adjusted manually in a profile projector. The work piece is

placed below the lens and a highly magnified image is formed on the horizontal

screen. A master is made by enlarging on a butter paper or trace paper so as to

check any irregularities present in the piece. Then the work piece is subjected

to further machining ( if possible ), and again checked under the projector. This

cycle is repeated until and unless the required dimensions of the job are

achieved.We were shown a Height Master for measuring the diameter of

holes. For that we had to first touch the bottom of the hole with the tip of the

instrument and set it to zero. Then the tip is moved vertically upward by

rotating the scale, and the movement is stopped as it touches the top. The

instrument displays the distance moved vertically on the LCD. It is basically

used for fast inspection purposes.

Another form of Height Master, connected to an external digital counter was

also shown. The purpose was same as that of the previous one but the

arrangement was different. Its demonstration was given in order to find the

height of a work piece