ACKNOWLEDGEMENT

We take this opportunity to express our profound gratitude and deep regards to our guide Mr. Rajesh Arya for his exemplary guidance, monitoring and constant encouragement throughout the course of this project work. The blessing, help and guidance given by him from time to time shall carry us a long way in life on which we are to embark.

We extend our sincere regards to Mr. Mahipal, Mr. Jitender Choudhary, Mr. Kirpal Saran for their commendable help and guidance during the course.

Several of well-wishers extended their help to us directly or indirectly and we are grateful to all of them without whom it would have been impossible for us to complete this project in time.

By

ANNU SINGH

2

CERTIFICATE

This is to certify that the Project work entitled, “To minimize hose leakages, Fastener security and Paint Defects” and submitted by ANNU SINGH for the partial fulfillment of the requirements of B. Tech (7 th Semester, Mechanical Engineering) Degree of embodies the bonafied work done by him under my supervision.

Signature of Supervisor

Mr. Rajesh AryaProduction HeadJCB India Limited-Ballabgarh

3

Contents

Introduction

Project 1 – Leak proof analysis

o Aim

o Losses due to leakages

o Major points of leakage

o Methodology

o Prominent reasons for leakage

o Proper Inspection (Inspection zone)

o Rotation Method

o Return feed pipe leakage and its solution

o Conclusion

o Effects of our experiments

Project 2 – Fastener Security

o Fasteners – Screws, Bolts, Difference between screw and bolts

o Defects in fasteners

o Causes

o Effects

o Prominent fastener defects

o Methodology

o Solution

4

Project 3 – Paint Defects

o Introduction – Paint shop

o Major paint defects

o Paint defects – fish bone diagram

o Solutions

5

INTRODUCTION

JCB is a family business named after its founder Joseph Cyrill Bamford, producing distinctive yellow-and-black engineering vehicles, diggers ("Backhoes") and excavators. In the UK as well as in India the word "JCB" is synonymous with any such type of engineering vehicle, although it is still treated as a trademark.

Company

The company was founded in October 1945 in Uttoxeter, Staffordshire, England and is today headquartered at Rocester. Other UK factories are at Cheadle, Uttoxeter, Rugeley, Wrexham and Foston. JCB has factories in India at Ballabgarh (Haryana) and Pune, United States at Pooler, Georgia and Brazil at Sao Paulo. In 2005 JCB purchased its first company since 1968 when it bought Vibromax (a German compaction equipment company), and it has just opened a new factory in China at Pudong close to Shanghai. The first vehicle that Joseph Cyril Bamford made was a farm trailer made from war-surplus materials.

HISTORY-JCB India

CORPORATE HISTORY

1979: JC Bamford Excavator Limited, world renowned ENCE manufacturer, & Escorts Limited a major Indian engineering conglomerate and player in the Indian Earth moving and Construction Equipment Industry (EMCE) joint hands to foreign Escorts JCB limited (EJCB) a joint venture company.

1980: Plant located at Ballabhgarh 30 kms from Delhi starts operations and rolls out its first- an excavator loader. The Excavator –Loader was a concept machine

6

for the Indian EMCE market making the beginning of mechanization of small and medium sized jobs. The first model was JCB 3C Mark III.

1980-1982: These two and a half years were spent in product adoption and improvement and during this period, two succeeding models JCB 3C Mark IV and JCB 3C Mark V were launched. Each model was a further improvement on the previous one. All three models were extremely successful as they were widely accepted this new concept and midsized machine. These machines were used for loading, dodging, trenching, road building, mining, etc. This machine served the market for 5 years.

1984: EJCB started appointing dealers to provide after sales support to the machines in the field- the only ones of their kind then and even now.

1987: EJCB further improved the excavator loader and launched JCB 3D. This is the largest selling model in the country.

1989: EJCB completed the first phase of appointment of a countrywide dealership network, comprising over 20 dealerships with 50 outlets.

1991: EJCB made massive investments in its plants to give better-finished machines. The installation of the shot blasting machines and a state of art paint shop, helped give a finished and longer lasting paint, making machines more durable.

7

1992: This saw the launch of 2 new machines. One was a bigger Excavator Loader- JCB 5D, giving better excavation and loading capacities and the other was JCB 430Z Articulated Loading Shovel the best in its class.

1993: The JCB 530 Telescopic handlers was launched. This machine is capable of performing varied jobs such as that of a loader, crane, forklift, and maintenance platform. It was a huge success with industries and the armed forces. Till date, EJCB is the only manufacturer of such a machine.

1995: EJCB become the first company to be accredited with ISO 9001. In addition, this was the year when EJCB sold over 1500 machines. The plant capacity was enhanced to produce 2000 machines a year.

1996: EJCB started deports in zones to provide parts supports to the dealers and reduced machine downtime.

1997: The JCB 4CX Excavator Loader was launched. This machine set standards such as operator comfort, styling, all terrain capability, productivity and reliability.

1998: By this year EJCB had totally sold over 10000 machines and had over 100 dealers.

1999: JCB increased its stake from 40% to 60%. The JCB 3D was redesigned with a more powerful engine and hydraulic system and a more comfortable cabin. Its sales cross the 12000 mark.

8

2000: Enhanced its range by offering the JS 200 Tracked Excavator and JCB Skis Steer Loaders. Also launched the 2-wheel drive version of JCB 4CX and the new look JCB 3D.

2001: Globally, JCB the fifth largest manufacturer of construction equipment in the world grew its worldwide market share to over 20% to regain its position as the no. 1 manufacturer of Backhoe loaders in the world.

2003: EJCB is bought by JC Bamford Excavators Limited and becomes JCB India Limited.

PLANT LAYOUT

9

FBU

(Fab

ricati

on B

usin

ess

Uni

t)

FBU

(Fab

ricati

on B

usin

ess

Uni

t)

PAINT

SHO

P

10

MAIN

FRAM

E

MAIN

ASSEMBLY LIN

E

TESTING AREA

REWORK AREA PRE DISPATCH INSPECTION

DIFFERENT DEPARTMENTS AT BALLABGARH PLANT

Manufacturing TBU (Transmission Business Unit) ABU (Assembly Business Unit) FBU (Fabrication Business Unit) Paint Shop CMD (Central Materials Deptt) Projects ME (Manufacturing Engineering) CPD (Central Purchase Deptt) Product Support Marketing Finance

BUSINESS UNITS OF JCB

Besides this the company is also divided into following sections which are regarded as the business units of the JCB, a term which according to them has no special significance in with inter-department linkages, but has not seized to exit. Following are the business units:-

1. ASSEMBLY BUSINESS UNIT (ABU)

2. WELD AND FABRICATION BUSINESS UNIT (FBU)

3. TRANSMISSION BUSINESS UNIT (TBU)

4. PAINT BUSINESS UNIT (PBU)

11

Product Range at JCB

Backhoe Loader Skid Steer Loaders Telescopic Handlers

Tracked Excavators Wheeled Loaders Vibratory Single Drum Compactors

Product MADE at JCB Ballabgarh Plant

JCB 3DX (BACKHOE LOADER 2WD & 4WD) JCB 4DX (BACKHOE LOADER 2WD & 4WD) JCB LIFTALL

HYDRAULICS

12

The machine can dig out the ‘difficult material’, thanks to the excellent tear out forces of the buckets. And the boom and dipper design allows it to dig ‘up to the rear frame’.

The unique JCB Vari-matic hydraulic system adjusts the pressure and flow rate depending on the conditions of earth to ensure the best combination for highest productivity.

It automatically increases digging power of the excavator end by switching the flow from one pump directly to the tank. This allows the remaining pump to develop the pressure necessary to overcome ground resistance. As the ground resistance reduces, the system automatically reverts to maximum flow for operational speed.

An additional push-button on the loader lever disengages the transmission, making the entire engine power available to the hydraulic system for extra breakout forces required at the time of cutting into the stockpile

JCB is a renowned name in the industry of construction equipment machineries. The machineries are well designed, re-analyzed by a group of several engineers. All these machineries have special arms for loading and unloading weights. The actuations of these arms are controlled by the motion of a special kind of hydraulic fluid. These fluids are made to flow into the cylinders of ram/piston from either side, thereby causing the motion of the arm/piston rod.

The motion of the piston/ram with the fluid flow can be understood by the following pictures.

13

ASSEMBLY LINE LAY OUT

14

Inner leg & valve block fitment

VECHILE

ASSEMBLY

LINE

ASSEMBLY LINE

Assembly line is equipped with modern machines, tools, high load capacity cranes and skilled labour. Assembly line follows sequence of operation to assemble the machine.

15

Gearbox/axle Engine assembly

King Post

Assembly

Hydraulic

Assembly

Loader arm

Assembly

Axle assembly

Cooling package

Bonnet assembly

Tyre assembly

Excavator and Loader bucket assembly

Tank fitment

Cab assembly

Boom Dipper Assembly

1. Leg FitmentLeg fitment consists of inner leg fitment in main frame. Hydraulic ram is also fitted inside the inner leg to give them motion. Inner is fitted to give a strong pivot to machine at the time of any operation. Leg is also fitted with foot which form the base of the both legs.

Leg fitment2. Front axle Fitment :

Front axle is fitted to main frame with the pivot pins and nut &bolts .Later tyre is fitted at the both ends of the front axle. Front axle also consists of various parts like axle beam, track rod, hub carrier, and steering arm.

16

Picture of the front axle of a backhoe loader

3. Loader valve block and Excavator valve block fitment:Loader valve block and excavator valve block and some feed pipes are fitted in to the main frame. Loader valve block is fitted to give motion to loader bucket which is fitted on the loader arm at the front of the machine.

17

Excavator valve block is fitted to give motion to excavator bucket which is fitted at the back of machine with boom and dipper.

Picture showing loader valve block.

18

Excavator valve block:

4. Tank fitmentTwo tanks are fitted on the both sides of the main frame, one is hydraulic tank and other is diesel tank

19

Picture showing fuel tanks n hydraulic tank.

5. Engine and rear axle fitment Engine and rear axle is fitted with machine, which provides necessary power to run the machine .Engine capacity varies from machine to machine, like engine of 3DX varies from 4DX.

6. Cooling Package Fitment:

20

Cooling package include radiator, oil filter and mud filter. Special type radiator is use to provide efficient cooling to engine.

Oil filter is provided for the filtering of oil before going to engine, it filters out any unwanted particle from the oil.

Mud filter is also a special type of filter which separate dust from the oil, to prevent engine from getting choked.

7. King Post Carriage (K.P.C) fitment:King post carriage is fitted to the rear frame .K.P.C unit consist of two different component king post and carriage .In between these two component slew rams are also fitted .Hydra clamp is also fitted on the corners with K.P.C which provide very tight grip with rear frame.

21

King post carriage

8. Loader arm fitment :Loader arm provide lifting movement to loader bucket. Loader arm consist of two arms which are further fitted hydraulic rams, which provide necessary lifting movement to loader arm, use for loading and unloading the material in loader bucket.

22

9. Battery is fitted to provide power to run the various lights attached to machine. Bonnet is fitted to provide safety to radiator, engine and battery.

10. Cabin fitment:

Cabin is fitted on the top of the main frame, cabin is control house of entire machine .Cabin include steering, electric board various switches which is used for controlling the various mechanism of the machine. Electric board consist of various indicator which show the level of hydraulic oil, transmission oil, water temperature, etc.

23

11. Tyre fitment:

Tyres are fitted on rear and front axles of the machine .Tyres are of different diameter at both the axle

There are separate shop for the fitment of rear tyre and front tyre.

Rear tyres used in backhoe loader are of two types:

Heavyduty – many nuts are fitted (identification mark)

Standard frame – flat surface ( identification mark)

Heavyduty tyres are of 20 ply and standard tyres are of 12 ply.

24

Flipper is used in heavyduty tyres only not in standard tyres.same air

pressure is used in standard and heavydutytyres.

Air pressure range in rear tyres vary from 40 to 45 psi.

Super tyres. Front tyres used in backhoe loader are of two types :

Super tyre.

Standard tyres.

Super tyre has no flipper . super tyre has air pressure range from 40 to 45 psi.

Standard tyre has airpressure range from 80 to 85 psi.

25

Standard tyres

12. Roll –off:

Roll-off is divided in to three units.

26

Oil filling. Boom-Dipper fitment to machine Buckets fitment to machine.

1. Oil-filling:

Various oils such as diesel, transmission oil, hydraulic oil, coolant are filled in the machine. Diesel and Hydraulic oil are filled in the oil tanks while transmission oil is filled in the engine. Water is also filled which get mixed with coolant oil.

In oil and fuel filling station,five types of oil are filled as below:-

Serial no. Oil type Quantity

1. Hydraulic oil 67.2 L

2. Transmision oil 16.8 L

3. Diesel 30 L

4. Engine oil 10.1 L

5. Coolant 17.1 L

These oils at this optimum quantity is very necessary for smooth and efficient

running of the machine is lower value can cause difficulty in its running in future.

27

2. Boom-Dipper fitment to machine:

Boom-Dipper is fitted with slew ram with the pivot pins and nut & bolt. Hydraulic rams are also fitted in the boom and dipper which provide necessary movement to boom and dipper.

s

3. Buckets fitment to machine:

Both loader bucket and excavator bucket is fitted to machine. Loader

28

bucket is fitted to loader arm while excavator bucket is fitted to dipper.

13. Vehicle testing:

After complete assembly machine is tested, all the component are

checked, movement of boom & dipper also tested.

BOOM –DIPPER SUB ASSEMBLY:

1. Boom Sub- assembly:Boom is fitted hydraulic rams which provide movement when it is attached with machine .two hydraulic rams are fitted in it .rams are fitted in the pin hole by using the pivot pin and later tighten by using nut & bolt. Hydraulic pipes are also fitted in the rams which provide oil supply to the machine. Seals and clamp also fitted on the boom.

2. Dipper-Sub assembly: In boom various parts are fitted to it complete assembly .Hydraulic ram is fitted

in it which is responsible for its various movement.ram is fitted in pin hole by using pivot pin which get tighten by using nut and bolt .After that tipping pin and tipping lever is fitted on the dipper ,excavator bucket is later attach with through tipping pin.

ENGINE SUB-ASSEMBLY:

29

Engine sub-assembly mainly consists of three parts main engine, gear box, torque converter, and fly wheel.

1. ENGINE – Engine is that part of machine which provides necessary power to machine .As backhoe loader required a good amount of energy so engine required is of very high capacity.

A kirloskar 76 HP ,gross power 56 kw at 22oo rpm ,four cylinder ,water cooled engine is installed in the machine which provide continuous power supply in even in dusty and rough environment .Engine is fitted with very high performing system which continuously through out heat produced in the engine thus enabling the engine to provide continuous power supply.

2. TORQUE CONVERTER – Torque converter is a modified form of fluid coupling that is used to transfer rotating power from a prime mover, such as an internal combustion engine or electric motor, to a rotating drive load. Like a fluid coupling, the torque converter normally takes the place of a mechanical clutch, allowing the load to be separated from power source. Unlike a fluid coupling, however, a torque converter is able to multiply torque when there is a substantial difference between input and output rotational speed thus providing the equivalent of a reduction gear.

3. FLY WHEEL –fly wheel is a rotating disc used as storage device for kinetic energy. Fly wheel resist change in their rotational speed which helps steady the rotation of the shaft when a fluctuating torque is exerted on it by its power source such as piston –based engine or when the load placed on its intermittent. Fly wheel cab be used to produce very high power pulse as needed for some experiment,

30

where drawing power from the public network would produce unacceptable spikes. A small motor can accelerate the flywheel between the pulses.

4. GEAR BOX – JCB transmission provide a superb drive power in all condition. It consists of 4-speed fully synchromesh gear box with electrically operated reversing shuttle. Reversing shuttle switch can change can change machine direction while allowing operator to keep hands on steering.4-pattrn gear lever with transmission disconnect switch add to overall ease of operation. Modern gear box reduces the unsuitable high low torque to allow higher forces to be generated.

BOOM –DIPPER ASSEMBLY:

In boom –dipper assembly, both boom and dipper are attached to each other using the pivot pin, clamp, nut & bolt which later send for fitment to machine.

RADIATOR ASSEMBLY:

JCB use excellent cooling mechanism for the engine so that it can provide continuous power even in dusty environment. Cooling unit of radiator, hydraulic cooler for cooling of hydraulic oil which continuously flow, for providing lifting mechanism, crown &crown plate, seal are the other components of the radiator package.

KING POST CARRIAGE (KPC) ASSEMBLY:

KPC is fixed with rear frame which provide supporting mechanism to boo-dipper.KPC is combination of various component king post, carriage, slew ram, trunion plate, boom lock, feed pipe, boom lock pin, bushes and seals.

31

HYDRAULIC ASSEMBLY:

In this assembly three major component of the machine get assembled. Excavator vale block, Loader valve block, and Hydraulic pump.

Excavator Valve Block (EVB): It include EVB mounting plate, valve block, various adaptors, hose pipe and

nut & bolt. EVB mounting plate provide base for whole valve block. On the

EVB plate valve block is fitted on which various adaptors are fitted which

provide inlet and outlet way for hydraulic oil.

EVB is used for controlling the movement of excavator bucket.

Loader Valve Block: Loader valve block is used for controlling the movement of loader bucket.

In this, main valve block which provide flow of hyd.oil to various mechanism

which control the movement of loader bucket.

Hydraulic Pump: It is the major component of the machine which provide sufficient oil pressure to control the hydraulic function of entire machinery. It provide a pressure of 3300 psi with pump flow of 101lpm at 2200 rpm.

32

CAB ASSEMBLY:

Cab is the operating room of the entire machine. It has glass around which provide excellent visibility all around, plenty of walking space, fully adjustable seat with soft touch steering wheel. It has a instrumentation panel which provide engine speed, engine hours, fuel level and water temperature. It has audible and visual warning system coolant temp.,engine oil pressure, pressure, transmission oil pressure, block air filter and hand brake on.

MACHINES MANUFACTURED

JCB’s advance range of back hoe loader includes 3DX and 4DX.These are the machines that promise versatility and high promise with the high fuel efficient engine and superb maneurablity. They optimize the strength and durability backed by the power loader performance.

33

JCB 3DX BACK HOE LOAEDER :

JCB 3DX backhoe Loader is finest machine produced JCB .It is widely used construction industry. It is worldwide recognized machine.

SPECIFICATION:

BHP = 76HP

Loader Bucket Capacity =1.1 cu m

Excavator Bucket Capacity = .24 cu m

Digging Depth = 4.77 m

ENGINE:

76 Horse Power fuel efficient engine with increased size cooler for better performance in hot and dusty working condition.

Low fuel consumption. Advance design transmission to provide to provide better movability.

PERFORMANCE:

Improved performance. Increased diesel tank capacity. Increased protection excavator hoses and improved excavator valve block

feature

JCB 4DX BACK HOE LOADER :

34

JCB 4DX back hoe loader having increased engine power capacity to provide more power to machine to lift more load and provide more strength.

SPECIFICATION:

BHP = 90 HP

Loader Bucket Capacity =1.1cu m

Excavator Bucket Capacity = .24 cu m

Digging Capacity = 4.77

ENGINE :

90 horse power engine provide more power with increased size of cooler to provide better cooling to engine.

New transmission to provide high traction of power.

Low fuel consumption.

PERFORMANCE

Increased shovel capacity with higher brake power

35

Higher productivity

Improved performance, increased diesel and hydraulic tank.

PRODUCTION UNIT

Production unit is divided in to four units.

1. Fabrication unit

2. Assembly unit

3. Paint shop

4. Transmission

FABRICATION UNIT

In fabrication unit various components are welded to give shapes to form the various parts of machine like mainframe, rear frame, etc.

Welding is a fabrication process that joins the materials, usually the metals by causing the coalescence. This is often done by melting work piece and filler material that cools to become strong joint to produce the weld. In fabrication unit MIG (metal inert gas) or gas metal arc welding.MIG welding used high deposition rate welding process .Wire is continuously feed from spool.

In Welding unit, space is divided for the fabrication of different component .Company produces almost all major component in the fabrication

36

unit .Major component which are produced in the fabrication unit are mainframe, rearframe, loader tower, boom, dipper loader arm.

In fabrication unit there is robotic cell, robotic arms which are used for the welding of loader tower .Robotic arm ,NX -100 Motoman imported from JAPAN, has six axis of rotation and has weld duration of 42 min and has output of 54 component. Robots employ arm and have rotating joist just like human arm. This creates an irregularly working shaped robotic working zone.

JCB is using the new technology and proper protection which reduces the chances of injury and other accident associated with welding .To prevent any accident welder wear personal protective equipment in the form of leather gloves, goggles and protective long sleeve jacket to avoid exposure of extreme heat and light.

LEAK – PROOF ANALYSIS

Aim:

The aim of our project is to determine the cause of hydraulic leakages that has been occurring in JCB machines and to provide adequate solutions to minimize these leakages. We begin our report with a brief description of the mechanism involved in the hydraulic movements introduced in the machines.

37

As we have clearly understood the mechanism involved in each movement, we now move on to describe the losses that take place due to hydraulic leakages.

LOSSES DUE TO LEAKAGES:

The losses inherent with hydraulic leakages can be categorized as below:

1. Make up fluid: Though this loss may seem very small but what we fail to realize is that a cumulative effect of this type of leakage can prove to be quite expensive in the long run.

2. Clean up: A lot of time, money and labour are spent in the cleaning up of the mess created due to leakages.

38

3. Disposal: Environmentally acceptable disposal of waste oil and absorbent material containing waste oil costs money.

4. Contaminant ingress: Where oil leaks out, contaminants such as air, particles and water can get in. Costs to consider here include:

Hydraulic component damage and fluid degradation as a result of contaminant ingress.

Hydraulic system reliability problems.

Removal of ingested contaminants.

5. Decrease in efficiency: As lot of time is wasted in all these rectification procedure which affects the production time to a large extent.

These losses may amount to extra expenditure which can be minimized by methods that shall be discussed in the preceding sections.

Before mentioning the causes and their solutions it is necessary that we become familiar with the sixteen hydraulic points that we have to study. These have been clearly mentioned below:

MAJOR POINTS OF LEAKAGE:

There are basically 16 main points in JCB’s 3DX and 4DX models through which leakage occurs. These points are categorized according to their respective zones as shown below:

Zone 1:

39

EVB Hose Leg ram hose Slew ram hose

Slew ram feed pipe dotty seal

Zone 2:

40

Return feed pipe adaptor Hydraulic pump T adaptor Hydraulic Cooler hose

LVB hose adaptor Radiator hose bend coolant

Zone 3:

41

Cab bottom brake pipe Rear axle top side brake

Orbital unit hose Lift ram hose

42

Zone 4:

Bulk head hose Dipper ram hose

As we have seen the major hydraulic points let us now discuss the procedure we adopted to identify the leakages and then to rectify them.

Methodology:

43

Studied all the 16 hydraulic points

The figure below shows a diagrammatic representation of the probable causes of leakages and their respective solutions. The circles in red signifies the probable causes and the boxes in blue signifies their solutions.

Prominent reasons for leakages:

44Prominent reasons for leakages

Prominent reasons for leakages

Complete inspection of machines for 3 days

Reduced the no. of machines that were inspected for 2 days

Left all the machines uninspected for a day

Compared the Hot Bay Test report for these 3 periods

All leakages duly noted

Assembly line leakages

As we are clear with the causes of leakages let us discuss the preventive measures, which are shown below:

45

ManMan

ManufacturingManufacturingMachineMachine

Faults in torque wrench

Calibration per month

Calibration per month

No prior calibration Wear and

tear

teartea

Expansion due to heat

Cut in hose pipe Absence of

O ring

Presence of burs in hose pipes

o ring might get

damaged

Improper finishing causing leakage

Proper filing of edges

Proper filing of edges

Tapering of O ring

Negligence of worker

Proper alignment

Proper alignment

Loose fitting Over torquing

Contamination

Caps should be properly closed

teartea

Caps should be properly closed

teartea

Proper InspectionProper Inspection

Proper Inspection:

It is quite inevitable a proper inspection technique has to be created in order to prevent hydraulic leakages in most of the machines, as maximum number of leakages occurs due to operator negligence. This can be proved based on our data collection during the past week in which we found that most of the hydraulic points were hand loose during the assembly procedure itself. The below graph depicts the number of points we found hand loose for the past six days of our inspection in the assembly line:

Thus we have devised a method to significantly reduce the number of leakage points during the assembly line itself. This procedure includes the introduction of an inspection zone. This inspection zone includes region from the point where the cab is placed above the machine framework up till the point where the loader arm is set on the framework. It requires one or two operators who can

46

inspect the major points of leakages (i.e. 16 points) if it is hand loose or not in this inspection region.

Features:

The introduction of the inspection zone has the following features:

As most of the hydraulic points, that are prone to leakages, are open in this region, it provides easy inspection vicinity to cover the major points.

A maximum number of six machines can be inspected in a minimum time frame of 8-9 minutes by an inspecting operator or a minimum time frame of four minutes by two operators.

An inspection free phase of 30- 40 minutes can be easily accommodated in between each inspection time frame.

Advantages:

The introduction of inspection zone provides the following advantages:

A lot of time wasted in the Hot Bay and PDI zone to rectify the leakages due to worker’s negligence can be easily saved.

This time can be utilized for proper inspection of leakages using UV lamps for minor leakages which cannot be identified by manual inspection.

Hydraulic oil losses can be minimized, saving a lot of money.

Expenditure related to clean-up of leakages, disposal and contamination can be easily prevented.

Why Inspection Zone is necessary?

The graph shown below will clearly signify the importance of an inspection zone in the assembly procedure:

47

The graphical data has been obtained based on our experiment in which we left most of the machines, uninspected. As it is clear that more leakages have occurred during this uninspected period, it further strengthens our suggestion to introduce an inspection zone to provide a leak proof machine.

ROTATION METHOD:

The evidence that leakages are primarily dependent on the worker can be easily deduced by the graph shown below:

Before and after lunch comparison graph

48

The above graph clearly indicates that most of the leakages occur after the lunch period, as most of the workers become lethargic.

Analysis of the above graph: The shift in the graph is caused because, repeating the same job over and over again, the worker loses his interest in the job. In order to rectify this difficulty it can be suggested that a method of rotation work be introduced, such that the total workers can be divided into four groups and assigned each zone. Now if we consider the working hours to be 8 hrs. We divide it into four segments of two hours each. Now at the commencement of assembly, each group of workers can be assigned each zone for a period of two hours. At the end of two hours, the group working in zone 1 should be shifted to zone 2, zone 2 to zone 3, and so on. A

49

Group A

Advantages: This method will keep the worker interested in his job, as the repetitive nature is considerably

eliminated. The worker will be skilled to work in all four zones, thus expanding his expertise.

Leakages caused due to hand loose joints can be considerably reduced.

RETURN FEED PIPE LEAKAGE

50

ZONE 1

ZONE 2ZONE 4

ZONE 3

Group B

Group C

Group D

RETURN FEED PIPE

RETURN FEED PIPE

To perform torquing in Hot Bay:

As a lot of problems are faced to performing adequate torquing in the assembly line due to insufficient torquing space, we can perform this operation very easily in the hot bay. In the inspection zone when the JCB is stationary, a lot of space is available below the machine where an operator can easily perform this torquing.

51

ManMan

MachineMachine

ManufacturingManufacturing

Negligence of worker

Tapering of O ring

Proper alignment

Proper alignment

Over torquing

Loose fitting

Contamination

Caps should be properly closed

teartea

Caps should be properly closed

teartea

Proper InspectionProper Inspection

Cut in hose pipe

Absence of

O ring

Presence of burs in hose pipes

O ring might get damaged

Improper finishing causing leakage

Proper filing of edges

Proper filing of edges

Uncalibrated torquewrench

No space for torquewrench

Design new torquewrench

Design new torquewrench

Replace the metal pipe

Replace the metal pipe

To do torquing in Hot Bay

To do torquing in Hot Bay

Thus as the machine leaves the assembly unit it has to be directly taken to the inspection zone rather than to the oiling and greasing section.

Replacement of the metal pipe:

Another way of tackling this problem is to simply remove the metal pipe connecting the hoses from the oil tank and the hydra cooler. If a single hose pipe is used from the hydra cooler to the oil tank then there will be no torquing problem as both the joints are easily available for torquing.

52

ASSEMBLY LINE

Oiling and greasing Bump test Roll test Inspection zone

Pre-rectification PDI and hot bay test

Place the machine above the hollow space.

An operator shall then go below the machine through this hollow space.

He can then easily perform the torquing operation.

Current system:

Revised system:

CONCLUSION:

Thus we have identified the reasons for leakages and have adequately provided the necessary steps that has to be taken to avoid these leakages in the future.

53

Hose pipe

Hose pipe

Metal pipe

Effect of our experiments:

The graph below shows the variation in trend during our experiment phase and the trend for previous months when there was no significant inspection conducted:

The graph above signifies that our inspection and correction of the leakages led to a significant decrease in the no. of leakages.

FASTENERS

AIM: The aim of our project is to determine the cause of fastener looses that has been occurring in JCB machines and to provide adequate solutions to minimize such faults

54

A fastener is a hardware device that mechanically joins or affixes two or more objects together. Fasteners can also be used to close a container such as a bag, a box, or an envelope or they may involve keeping together the sides of an opening of flexible material, attaching a lid to a container, etc. There are also special purpose closing devices, e.g. a bread clip. Fasteners used in these manners are often temporary, in that they may be fastened and unfastened repeatedly.Items like ropes, strings, wires kept together by a plastic strip coating, cable, chain, or plastic wrap may be used to mechanically join objects, but are not generally categorized as fasteners because they have additional common uses. Likewise, hinge sand springs may join objects together, but are ordinarily not rwconsidered fasteners because their primary purpose is to allow articulation rather than rigid affixment.

Other alternative methods of joining materials are welding, soldering, brazing, taping, gluing, cementing, or the use of adhesives can be used. The use of force can also be used such as magnets, vacuum, of even friction.

SCREW

A screw or bolt is a type of fastener with a helical ridge known as the thread which is wrapped around a shaft or a cylinder. Mostly the threads are external threads, but sometimes the threads mate with the internal threads often in the form of nut or a cylinder with internal threads. Common use of the screw is to locate or fix objects together.

55

Screws have a specially formed surface at one of its end called head. Head is the section by which the screw is turned or driven, tools used to turn the screw are screw drivers, wrenches, etc. head is usually bigger than the body so that it locates the screw at a position rather than driving it deeper inside. There are exceptions for the heads also.

DIFFERENCE BETWEEN SCREW AND BOLT

A bolt is an externally threaded fastener designed for insertion through holes in assembled parts, and is normally intended to be tightened or released by torquing a nut. A screw is an externally threaded fastener capable of being inserted into holes in assembled parts, of mating with a preformed internal thread or forming its own thread, and of being tightened or released by torquing the head. An externally threaded fastener which is prevented from being turned during assembly and which can be tightened or released only by torquing a nut is a bolt. An externally threaded fastener that has thread form which prohibits assembly with a nut having a straight thread of multiple pitch length is a screw.

56

Defects in fasteners

1. Improper threading.2. Taper in the hole.3. Taper in bolts.4. Damaged threads due to improper handling.5. Over tightening of bolts.6. Improper meshing of nut and bolt.7. Discontinuity of flanks.8. Loose tightening of nut and bolts.

Causes

57

1. Improper threading

This results due to defects in the machines used for the production of bolts.

2. Taper in the hole

This results due to improper drilling of holes in lathe.

3. Taper in bolts

This is due to the backlash in the lathe.

4. Damaged threads due to improper handling

This can be caused by hammering the bolt in holes.

5. Over tightening of bolts

Such errors are generally caused by improper torquing of toque-wrench.

6. Discontinuity of flanks

Such errors are caused due to improper machining and giving greater depth-of-cut.

7. Loose in nut and bolt

These errors occur due to the operator negligence.

Effects

58

1. Because of various defects, the nut and bolt generally lose their strength and load carrying capacity decreases.

2. Due to regular usage, the nuts and bolts eventually become loose and may give up.

3. Sudden failure due to impact without warning can cause disastrous accidents.

4. The prestige of the company suffers a lot.

5. Presence of loose plays in the parts thus creating noise and vibration.

PROMINENT FASTENER

59

Slew ram cross bolt absent

Slew ram cross bolt absent

KPC-B KPC stopper link key bolt nut loose

KPC-B KPC stopper link key bolt nut loose

PROMINENT FASTENER DEFECTS

The following graph shows the FPM of each part of the machine in the new assembly line during the time of our inspection:

60

Prominent fastener defectsProminent fastener defects

KPC bulk plate MTG bolt loose

KPC bulk plate MTG bolt loose KPC Boom KPC

stopper MTG bolt loose

KPC Boom KPC stopper MTG bolt

loose

Prominent fastener defects

Material

Manufacture

Man Machine

Nut and bolt left loose

Nut and bolt left loose

Improper masking

Improper masking

1. Damaged thread

2. The hole is left unfastened

Improper pitch of lead screw

Improper pitch of lead screw

Vibration and backlash

Vibration and backlash

1. Worker negligence

2. Improper meshing

Contains the defects

Contains the probable reasons for the errors

Contains the effects

Methodology:

61

The graphical comparison of the hot bay report during and before our inspection:

Solution

62

Studied all the 20 fastening points

Number of machines inspected increased day by

day for 4 days

All lose fastening points duly noted

Left all the machines uninspected for a day

1. The new assembly line must be audited on daily basis to ensure security and proper fastening of bolts.

2. The holes must be properly masked so as to avoid the accumulation of paint which might lead to interference between the hole and bolt which might damage the thread profile.

3. It must be ensured that in PDI zone if any fasteners are loosed to do some working, must be again fastened properly by worker.

4. Slew ram cross bolt loose is generally due to 2 chief reasons:a) Mismatch of holes of pin & KPC in longitudinal directions.b) Circumferential alignment of hole in pin not perfect with KPC

hole.

To solve this we defect we propose two solutions as shown below:

4.1 To overcome this problem there should be another type of pin & KPC having male, female parts incorporated in them which makes sure proper orientation of the parts.

63

Key hole

Projection for groove

Pin body

Head

The projection (male part) shown above should be perpendicular plane to the bolt hole axis. Corresponding groove (female part) should be made in the bush and KPC, which is also perpendicular to the bolt hole axis. When the pin is inserted in the KPC the projections on the pin will allow both the hole axis to align in a perfectly straight line, thus the problem of misalignment can be solved to a great extent.

4.2 A second solution may also be proposed in which we completely remove the bolt and instead we introduce a lock pin on top of the pin. This is shown in the figure below.

64

Lock pin

Pin

PAINT SHOP

In paint shop coating of paint is done on every component of the machine. There is sequence of operation through which every component has to go through .Every step has to be performed very carefully to maintain proper quality of paint on each component.

Each step is supervised by skilled engineers and supervisors to reduce the chances of any defect or rejection .Paint shop follows the following sequence of operation.

Paint shop is equipped with latest equipment to meet the expectation of the esteemed client; a rigorous quality assurance is maintained and implemented at every step of operation.

65

The figure below shows the diagrammatic representation of the zones involved in the paint shop.

66

Metal burstingMetal bursting

Water RinseWater Rinse

Air BlowingAir Blowing

Masking ZoneMasking Zone

Powder SprayPowder Spray

Heat OvenHeat Oven

Even though a high standard of supervision is maintained some defects occur whose detailed explanations are given below:

Major Paint Defects

1. Over Paint:

2. Under Paint:

67

Reason -1. This problem is constantly faced in the fender. This is a simple case of worker’s negligence.

2. Secondly, the hangers that are used, block the area to be painted.

Effects- Loss in appearance.

Reason- This is not such a big issue in paint defects. This is caused due to overlapping of layers of paint.

Effects- Degradation of appearance.

3. Blow Holes:

4. Chip Removal:

68

Reason- This occurs due to improper machining.

Effects- Due to prolonged use, the chip may peel off, leaving an empty patch.

Reason- Due to irregularities in the surface texture, blow holes are to be found in some of the components.

Effects- The chances of rusting increases through these blow holes and its appearance is lost.

5. Spatter particles:

6. Scratches during assembly:

69

Reason- Deposition of weld beads over the joints.

Effects- Appearance of the component is lost due to the presence of spatter particles.

Reason - 1 Due to irregular movements occurring during transportation of components, fixtures hit with the components and scratches are formed.

2. They are also formed while joining two components due to the usage of hammer, etc.

Effects- It can be clearly seen in the picture.

7. Presence of Rust:

8. Water patches in loader arm:

70

Reasons: 1. Ungalvanised metal sheet.

2. Old stock.

Effects- The paint may rupture after prolonged use.

The exact reason is still not clear but we undertook the following procedure to investigate the exact reason:

1. Hypothesis: Water droplets may be present in the fixtures that may fall on to this part during spraying.Note: It should be noted here that such fixtures are used for other components, but as we have found through our investigation that there are no such patches found elsewhere.Result: This hypothesis is not applicable.

2. Hypothesis: Water droplets may fall from the conveyor belts during motion.Note: Again we should note that conveyor belts are used in all the components but such damage are not found in any other region.Result: This hypothesis is not applicable.

3. Hypothesis: Water may get stored in the holes of the loader arm which may fall later during motion.Note: It was found during our investigation that during the spraying no water was found in these chambers.Result: This hypothesis is not applicable.

Having learned about the major damages lets go further to the reasons that leads to these damages. The circles in blue shows the reasons for these damages.

71

PAINT DAMAGE

PAINT DAMAGE

Water Marks

Water Marks

Over PaintOver Paint

Under PaintUnder Paint

Blow HolesBlow Holes

Chip RemovalChip Removal

Spatter ParticlesSpatter Particles

ScratchesScratches

No specified reason

No specified reason

Over lapping of paint layers

Over lapping of paint layers

Non uniform painting

Non uniform painting

Entrapment of air pockets

Entrapment of air pockets

Improper Machining

Improper Machining Improper

grinding

Improper grinding

Impact during assembly

Impact during assembly

Presence of Hangers

Presence of Hangers

Ungalvanised metal

Ungalvanised metal

Old stockOld stock

Solutions:

1. Water Patches: As reason is still not clear it is difficult to suggest a particular solution.

2. Over Painting: It may be suggested that uniform layer of paint may be sprayed onto the component because after the paint melts during the heating zone the excess layer may clump together and ruin the beauty of the paint.

3. Under Painting:a. During most of the cases the fender is under painted, so it should

be duly noted by the painter and care should be taken by him not to ignore this spot.

b. Most of the hangers that are placed outside the mainframe should be placed inside the mainframe as accurate painting of this region is not mandatory.

72

RustRust

4. Blow Holes: The finishing of the component must be improved so as to prevent the formation of blow holes.

5. Chip Removal: Proper care should be taken during machining as chips are easily detached from the component and along with the chip the paint is also removed.

6. Spatter Particles: Grinding method should be improved and if possible manual filling should also be done.

7. Scratches: Padding of any sort is advisable to be placed in parts where frequent paint damages are observed. Padding may be of some kind of rubber, thick paper, etc.

8. Presence of Rust: Hand held grinder should be used to remove the rust completely and galvanization should be done to prevent it.

73

Hanger placed outside

Hanger placed inside

74

Acid / Solvent Attack

DESCRIPTION

– Irregular patches of roughened, discoloured, partly stripped or disintegrating surface, possibly with crazing or cracking in the affected area. Traces of the attacking substance may be present.

a) accidental spillage of corrosive substances: brake fluid, peroxide or battery acid

b) acid rain standing on the surface

c) use of detergents on new surfaces

CAUSE

– Chemical corrosion of the paint film. This is often due to: a) accidental spillage of corrosive substances: brake fluid, peroxide or battery acid

b) acid rain standing on the surface

c) use of detergents on new surfaces

75

PREVENTION

a) Maintain good housekeeping practices, and protect surfaces when working on vehicles

b) Protect vehicle during outside storage

c) Avoid using detergents on newly painted surfaces

REMEDY

– Light damage may be remedied by flatting, compounding and polishing. In the event of more severe attack, remove the paint down to a sound surface, ensure that all traces of contaminants are removed, and repaint.

Bleaching

DESCRIPTION

Yellowing of the surface corresponding to areas of filler in the substrate

76

CAUSE

a) Excess quantities of peroxide used in the filler.PREVENTION

Use a feed machine for mixing filler, or take care to calculate and measure peroxide quantities accurately.

REMEDY

– Rub down the affected area to the surface of the filler, seal with isolator or epoxy primer and repaint.

Bleeding

DESCRIPTION

– Discolouration of the topcoat, either in the form of a halo or, in severe cases, a complete colour change. This defect usually only occurs when spraying over red or maroon paint.

77

CAUSE

a) Absorption of pigment from the underlying paint, dissolved by the solvents of the new coat.

PREVENTION

a) Test the original finish by spraying a small, flatted area.

b) Use an approved bleeding inhibitor sealant.

c) Remove any overspray from the surface before painting.

REMEDY

Rub down to the original finish, seal with a recommended sealer and repaint.

Bistering

78

DESCRIPTION

– Blisters appear as swellings on the surface of the paint and vary considerably in both size and density. Coarse blisters, larger than 1.5mm in diameter, generally occur in patches, although they may also be found in isolation. Fine blisters, typically from 0.5mm rings, meandering lines or in the shape of a finger print. Blisters in the colour coat are generally more prominent than those occurring between paint and substrate.

CAUSE

– Moisture or contaminants trapped under the surface. This may result from:

a) Inadequate surface cleaning, leaving residual moisture or contaminants such as oil, industrial pollutants or grease from finger tips.

b) Incompatible materials or the use of non-recommended thinners.

c) Insufficient thickness of paint leading to increased permeability.

d) Water permeating both newly applied and aged films. Exposure to rain or high humidity before the finish is fully hardened increases the risk of blisters caused by permeation.

PREVENTION

a) Protect vehicle surfaces when in store, and clean surfaces scrupulously before spraying.

b) Use only top quality recommended and approved materials.

c) Follow the correct spraying processes.

d) Avoid exposure to moisture and extreme temperature changes until the finish is fully hardened.

79

REMEDY

– Establish the depth and cause of the blister by pricking out with a pin and examining under a low power magnifying glass. Where the blisters occur between paint layers, the affected area may be sanded down to a sound surface and repainted. In more severe cases, or where the blisters occur between the undercoat and the substrate, strip down to the substrate and repaint.

Blooming / Blushing

DESCRIPTION

A milky white haze or mist formed on the surface of the paint film.

CAUSE

Moisture condensing on, and being trapped in the wet film - may be due to:

a)Spraying during cold, wet or humid weather.

b)Use of too fast or poor quality thinner.

80

c)Compressed air pressure too high, and/or poor spray gun set up.

d)Fanning compressed air onto the film to speed up solvent release.

e)Draughty paint shop, or inadequate heating and/or air movement.

PREVENTION

a) If possible, avoid spraying air drying paint during rainy or exceptionally cold or humid weather. If this is unavoidable, a non-bloom thinner should be used.

b) Use the correct grade of thinner.

c) Reduce compressed air pressure to minimise the cooling effect.

d) Allow solvent release to take place naturally.

e) Ensure that the paint shop is adequately heated, ventilated and free from draughts.

REMEDY

– Slight blooming may be removed by the use of polishing compound, after the paint film In more severe cases, rub down the surface, and repaint using the correct grade of thinner or non-bloom thinner. If these remedies fail to correct the fault, raise the temperature of the paint shop by a minimum of five degrees, avoid all direct draughts, flat and repaint the affected area. Note: blooming of the colour coat may indicate that the undercoats have been similarly affected, the defect having gone unnoticed due to their matt finish. This may subsequently give rise to blistering or loss of intercoat adhesion.

–

81

Blowing / Air Trapping

DESCRIPTION

Large rounded air bubbles or blisters, usually occurring in the area of seams and boxed in corners, or over heavily filled or plastic surfaces.

CAUSE

– Air trapped beneath the paint expands, resulting in the detachment of the paint film from the substrate. This frequently results from:

a) Poor application of filler, stopper or primer resulting in entrapped air.

b) Poor feather edging of chipped film.

c) Bridging of seams and boxed corners by the paint film.

d) Porosity and air pockets in the primer due to inferior or insufficient thinner, the compressed air pressure too high, or dry spraying.

82

e) Failure to prepare and seal substrate correctly, especially when spraying GRP.

f) Excessive application of heat during drying.

PREVENTION

a)Ensure correct application of filler, stopper or primer.

b) Feather edges of chipped film properly.

c)Avoid heavy paint application and ensure that the film penetrates seams and boxed corners.

d) Always use recommended thinner and correct spraying techniques. Apply primers in thin wet films.

e)Examine the substrate for porosity, especially for gel coat bubbles in GRP. Prepare and seal carefully.

f)Avoid excessive application of heat during drying.

REMEDY

– The paint must be removed to the depth of the bubble, any underlying defect remedied and the area repainted.

83

Chalking

DESCRIPTION

– A chalky dusting or powdering at the paint surface, often associated with old, weathered paint film.

CAUSE

– Precipitation of elements within the paint. This may be due to:a) Incompatible or defective materials within the paint.

b) Degradation of the binding agent.

c) Degradation of pigment.

PREVENTION

a) Use recommended materials.

b) Avoid exposure to ultra-violet light (strong sunlight) and harsh shampoos.

84

REMEDY

– Flat, compound and polish the surface to restore the gloss. In severe cases, repaint the topcoat.

Cissing / Fish Eyes

DESCRIPTION

– Small, crater like holes or indentations in the paint surface, varying in size from pinholes up to 1cm in diameter. Usually the larger craters occur individually, whilst the smaller ones are often found in small densely packed clusters. Small impurities are often visible in the centre of the crater.

CAUSE

– Variations in surface tension of the paint. The most common reasons for this are:

a) silicone in the environment or on the surface of the substrate; even minute traces are sufficient to cause cissing.

b) contamination by other sources, such as grease, dried soap, detergent, spray dust, wax, or oil from the spraygun.

85

c) incompatible elements in the primer.

d) saturation by fumes in the spray booth.

PREVENTION

a) Thoroughly clean any silicone polishes from the surface to be painted and avoid using silicone polishes in the vicinity of the paint shop. Prepare the surface using the same preparation procedure as that set out below.

b) Thoroughly clean the surface with wax and grease remover. Do not allow cleaning solvents to dry on the surface but remove with a clean dry cloth, using the cloth only once. Clean surfaces prior to sanding and always clean a larger area than that to be sanded. Ensure that all sanding dust is removed. Prepare bare metal surfaces with metal conditioner. Repeat the solvent cleaning operation prior to commencing spraying. Ensure that the spray gun and compressed air equipment is properly maintained.

c) Always use the recommended materials.

d) Ensure that the spraying area is properly ventilated.

REMEDY

– Remove the paint completely from affected area and repaint, following the recommended preparation procedure. In extreme circumstances it may be necessary to use an anti-cissing additive. Always consult the paint manufacturer before using such additives.

86

Clouding / Mottling

DESCRIPTION

Colour variation in metallic paint, with patches of lighter or darker tint, often in streaks following the direction of spraying.

CAUSE

– Irregular application density of the basecoat. This is a result of: a) poor spraying technique

b) poor pattern from the spray nozzle

c) paint too wet, insufficiently mixed paint, poor quality or wrong type of thinner

d) surface too hot or too cold

PREVENTION

a) Use the correct spraying technique.

87

b) Adjust the nozzle to the correct pattern before commencing spraying.

c) Ensure that the paint is thoroughly mixed to the correct consistency. Use only recommended thinner.

d) Ensure that the surface is within the recommended temperature range.

REMEDY

– If the clearcoat has not been applied, shade the base, otherwise rub down the surface and repaint.

Contamination / Industrial Fallout

DESCRIPTION

– Spots, speckles or splash-like deposits on, or discolouration and staining of, the paint surface. The surface may have greasy or tacky spots, be coated with particles, or feel gritty.

88

CAUSE

– Foreign substances or chemicals adhering to, or becoming embedded in the paint. Common sources are:

a) tree sap and resins, wet leaves, berries, fruit or bird droppings allowed to remain on the paint.

b) metallic particles becoming embedded in the surface of the paint and oxidising.

c) salt deposits resulting from the evaporation of liquids on the surface. These may also lead to blistering.

d) cement or other chemically active dust.

PREVENTION

a) Do not allow any deposits to remain on the paint surface.

b) Ensure the paint film is fully cured.

c) Store vehicles under cover and away from possible sources of contamination. Take special care not to expose new paint finishes to environments likely to cause contamination.

d) If an oven or drying room is used ensure that the filtration system is working properly, and that no industrial fumes enter the room.

REMEDY

– Light staining may be removed by washing the surface with a mild detergent solution, then washing with a 10% oxalic acid solution to remove ferrous compounds. Rinse, compound and polish to restore the gloss. If staining and discolouration persist, rub down the surface and repaint.

89

Corrosion / Rusting

DESCRIPTION

– Loose paint, bubbling and discolouration of the paint film, especially around body fittings, panel edges and seams.

CAUSE

– Corrosion of the metal substrate, resulting in loss of adhesion of the paint. This is frequently caused by:

a) exposure of bare metal surfaces by accidental damage, or byleaving drilled holes untreated.

b) exposure of bare metal surfaces due to destruction of the paint film by contamination.

PREVENTION

a) Ensure that all metal surfaces are treated with the correct metal treatment fluids and etch primer prior to painting.

b) Repair any damage to the paint film as soon as possible. Always treat any newly exposed metal edges immediately.

90

REMEDY

Strip the paint from the affected area down to the bare metal, remove all existing corrosion, treat the surface with the correct metal treatment fluids and etch primer, and repaint.

Cracking

DESCRIPTION

– Random breaks or crevices in the paint film, often adjacent to filled seams or panel edges. Cracks frequently take the form of a three pointed star. The depth of penetration of the paint film varies, severe cracks may penetrate to the substrate. Fine cracks or splits may occur at the feather edge of a spot repair shortly after the application of the topcoat.

CAUSE

– Weaknesses such as blistering being exaggerated by weathering, or magnification of stresses normally present in the paint film. These stresses are increased by:

a) inadequate mixing of materials prior to application, insufficient thinning or the wrong grade of thinner.

91

b) poor preparation of the surface, too coarse abrasives, inadequate cleaning or poor seam filling.

c) contamination by oil or water in the air line.

d) excessive film thickness and insufficient drying time between coats, cold air fanning causing the surface to dry over trapped solvent.

e) substrate too hot or too cold during spraying.

f) application of thermosetting topcoat over partially cured paint film or thermoplastic acrylic topcoat.

PREVENTION

a) always mix paint thoroughly, and use the correct amount of recommended thinner.

b) prepare the surface carefully, using the correct grade of abrasives. ensure that seams are correctly filled. clean surfaces thoroughly, paying special attention to feather edges.

c) always maintain compressed air equipment properly.

d) use correct spraying techniques. apply paint in thin, wet films and allow adequate drying time between coats.

e) ensure that the surface is within the recommended temperature range before commencing spraying.

f) isolate the thermoplastic acrylic with a light coat of epoxy primer.

REMEDY

– In minor cases, where only the topcoat is affected, sand down to a sound finish and repaint.

92

– If cracking has penetrated the primer, strip all paint from the affected area, ensure that any defects in the substrate are corrected and repaint.

Crazing Checking

DESCRIPTION

Appears to the naked eye as a loss of gloss, close examination under low magnification reveals a large number of minute cracks.

CAUSE

– Excessive stresses in the paint film due to: a) inadequate mixing of materials prior to application, insufficient thinning or the wrong grade of thinner.

b) excessive film thickness, colour coat applied over inadequately dry or excessively thick undercoats.

c) incorrect use of additives.93

PREVENTION

a) always mix paint thoroughly, and use the correct amount of recommended thinner.

b) use correct spraying techniques. apply paint in thin, wet films and allow adequate drying time between coats.

c) only use approved additives.

REMEDY

– Sand the affected area down to a sound, smooth finish and repaint.

Dirt / Seed / Bits

DESCRIPTION

– A rough, irregular surface to the paint film, is easily felt with the hand. The particles are often totally embedded in, and covered by the paint film.

94

CAUSE

– Contaminating particles incorporated in the paint. These may be the result of:

a) dust, dirt or threads falling from cloth or clothing or blown out of mouldings or panel joints during spraying, settling on the wet paint film.

b) dust not properly removed from the surface prior to spraying.

c) airborne particles settling on and becoming incorporated in the paint film during or immediately after spraying.

d) dirt in the paint or thinners resulting from open or rusty cans.

PREVENTION

a) ensure that cloths and clothing are clean and dust free, blow out mouldings and panel joints prior to spraying.

b) clean down and tack-off the surface prior to spraying each coat.

c) keep the spray shop clean and dust free, avoid sanding operations in the area of the spray booth. wet down surrounding surfaces if necessary, ensure that the filtration system is working properly.

d) keep all materials in clean, sealed containers and strain before use.

REMEDY

– Allow the paint to harden completely. Light surface dirt may be removed by flatting, compounding and polishing. Deeply embedded dirt, or dirt in synthetic paints, requires the surface to be rubbed down until smooth and repainted.

–

95

Dry Spray

DESCRIPTION

– A granular or coarse textured finish with no gloss.

CAUSE

– Paint being deposited on the surface in a powdery condition.a) viscosity of paint too high, use of incorrect or poor

quality thinner.

b) poor spraying technique, dirty spray gun, compressed air pressure too high, gun held too far from the surface during spraying.

c) spraying in draughts or in a high velocity airflow.

96

PREVENTION

a) Use the correct proportion of recommended thinner.

b) Use correct spraying techniques, ensure that equipment is clean, set air pressure as low as possible, consistent with proper atomisation, spray from the correct distance.

c) Use a spray booth, and ensure that air circulation and extraction is at the correct velocity.

REMEDY

– Flat, compound and polish. If the texture is too coarse for this to correct the defect, rub down the topcoat and repaint. Metallic finishes must always be rubbed down and repainted.

Dull Finish /Abnormal Loss of Gloss

DESCRIPTION

– Although apparently smooth and evenly applied, the surface lacks shine.

97

CAUSE

– Microscopic roughness of the surface which may result from:a) poor hold out of primer, or the application of topcoat over primer which is not thoroughly dry.

b) poor quality or incorrect thinner, or the use of additives in the paint.

c) incorrectly prepared or poorly applied paint.

d) application over a poor substrate.

e) excessively slow drying due to high humidity or low temperature.

f) solvent fumes or exhaust gases attacking the surface.

face contamination by wax, grease, oil, soap or water.

h) the use of strong detergents or cleaners on a newly painted surface, compounding too soon after painting or using compound which is too coarse.

PREVENTION

a) Use an approved primer, and allow to dry thoroughly before applying the topcoat.

b) Use only recommended thinner and approved additives.

c) Ensure that the paint is stirred thoroughly, apply under the correct conditions using proper spraying techniques.

d) Prepare the substrate thoroughly.

e) Ensure that the paint dries under warm and dry conditions.

f) Ensure good, draught free air over surfaces whilst drying.

98

g) Wipe the undercoat with solvent and dry thoroughly before applying the topcoat.

h) Avoid using strong detergents or cleaners on newly painted surfaces. Do not compound paint until thoroughly hard and always use the correct grade of compound.

REMEDY

– Normally the shine may be restored by rubbing down with abrasive compound and polishing. If the dulling is too severe for this to yield satisfactory results, rub down the topcoat and repaint.

Flaking / Peeling

DESCRIPTION

– The paint lifts from its underlying surface in smooth flakes. These flakes may be easily broken, with a tendency for the edges to peel away from the surface.

99

CAUSE

– Loss of adhesion between a layer of paint and its underlying surface. This may be caused by:

a) Contamination of the underlying surface by wax, grease, silicone, oil, release agents, water, corrosion or soap.

b) Incorrect or non-use of metal conditioner on steel or aluminium surfaces.

c) Inadequate keying of the surface.

d) Surface too hot or too cold when sprayed.

e) Use of the wrong primer process, primer not properly dry.

f) Incorrect viscosity of paint, use of wrong or poor quality thinner, compressed air pressure too high.

g) Paint film applied too thickly.

h) Build up of stress between two adjacent layers of paint.

PREVENTION

a) Ensure that the surface to be painted is scrupulously clean. Always dry the surface with clean cloths.

b) Always use the correct metal conditioner on steel or aluminium surfaces. Commence spraying within 30 minutes of preparation to avoid the onset of corrosion.

c) Sand the surface properly before spraying, taking care to remove all sanding dust.

d) Ensure that the surface is within the recommended temperature range during spraying and drying.

e) Use the correct primer process, and ensure that the primer is properly dry before continuing painting.

100

f) Thin the paint to the correct viscosity, using only the recommended thinner. Set compressed air pressure as low as possible consistent with proper atomisation.

g) Apply paint in thin, wet layers.

h) Use a range of products by a single paint manufacturer.

REMEDY

– Remove the detached paint from the affected area. Prepare the underlying surface correctly and repaint.

Inadequate Colour Coverage

DESCRIPTION

Underlying surfaces visible through the paint film, most frequently in hard to spray areas, on lower panels or on sharp edges and contours.

101

CAUSE

– Inadequate thickness or poor covering power of the colour coat. This is frequently due to:

a) Poor spraying technique.

b) Inadequate lighting, insufficient or cramped working space, inaccessibility of surfaces.

c) Poor mixing of materials.

d) Reduced thickness of the colour coat due to excessive to excessive compounding and polishing.

PREVENTION

a) Use the correct spraying technique, ensure even and adequate film thickness.

b) Work under good lighting conditions in a properly sized spray booth, pay special attention to inaccessible areas.

c) Ensure that the materials are thoroughly mixed.

d) Avoid excessive compounding and polishing. Take special care on edges and sharp contours.

REMEDY

– Flat the affected area and repaint.

102

Lifting / Wrinkling

DESCRIPTION

– Shrivelling, swellings, wrinkles or folds of varying severity at the paint surface.

CAUSE

– Non-uniform drying within the paint film. This may result from: a) Excessive film thickness.

b) Insufficient drying time between coats, forced drying, non- uniform air temperature.

c) Use of wrong or poor quality thinner.

PREVENTION

a) Apply paint in thin, even coats.

b) Allow sufficient drying time between coats, ensure correct, uniform drying temperature.

c) Use only recommended thinner.103

REMEDY

– Allow the film to harden thoroughly. If the defect is slight, flat, compound and polish the affected area. In severe cases rub down to the substrate and repaint.

Mapping

DESCRIPTION

– Areas of the surface with a differing texture or degree of gloss, surrounded by clearly defined boundary or contour lines.

CAUSE

– Filler or stopper incorrectly mixed, or not properly finished, primed or sealed.

PREVENTION

– Mix filler or stopper correctly, apply and finish carefully and correctly.

REMEDY

– Rub down the affected area to a sound surface, refill or stop if necessary and prime or seal thoroughly.

104

Off Colour / Poor Colour Match

DESCRIPTION

Adjacent areas exhibit differences in shade. This is most frequently noticeable on adjacent complete panels.

CAUSE

No single cause, the defect may result from a number of factors:

a) Use of differing or incorrect materials.

b) Inadequate mixing of the paint.

c) Fading due to weathering or exposure.

d) Incorrect application.

e) Metameric distortion (colour variation in differing light).

f) Incorrect colour choice or use of the wrong variant of the colour.

105

PREVENTION

a) Use only recommended materials.

b) Ensure that the paint is mixed thoroughly and correctly.

c) Protect vehicles in storage.

d) Apply materials correctly, use correct spraying technique.

e) Before painting the vehicle, spray a test panel with the paint to be used and compare with the original at different angles and in differing light.

f) Use the manufacturers colour system to select the correct colour and variant.

REMEDY Flat down the surface and repaint using the correct colour and variant.

Orange Peel

106

DESCRIPTION

– Pebbled, uneven surface of the paint film, similar in appearance to orange skin.

CAUSE

– Failure of the paint droplets to coalesce on the surface. This may be due to:

a) Poor spraying technique, spray gun too far from surface, incorrect compressed air pressure, incorrect nozzle adjustment.

b) Excessively thick or thin film. thin film.

c) Paint incorrectly mixed, wrong viscosity, poor quality or incorrect thinner.

d) Insufficient drying time between coats, cold air fanning to speed drying.

e) Incorrect ambient or surface temperature, draughts.

PREVENTION

a) Use the correct spraying technique and ensure that equipment is correctly adjusted

b) Apply paint in thin, even coats

c) Ensure that the paint is correctly mixed, use only recommended thinner with the correct grade

d) Allow sufficient drying time between coats

e) Spray within the re-commended temperature range and ensure proper ventilation

REMEDY

– Rub out the orange peel, compound and polish. In severe cases it may be necessary to flat and repaint the surface.

–

107

Overspray

DESCRIPTION

– Areas of granular paint particles adhering to, or partially absorbed in, the surface of the film.

CAUSE

– Spray dust deposited on the surface. This results from:a) Poor masking.

b) Paint from a subsequent application settling on the surface.

c) Compressed air pressure too high.

d) Inadequate extraction or ventilation.

PREVENTION

a) Mask carefully and completely, ensure that the edges of masking tape are thoroughly sealed

108

b) Protect adjacent surfaces from spray dust

c) Set compressed air pressure as low as possible, consistent with proper atomisation

d) Use a spray booth, and ensure correct air circulation and extraction

REMEDY

– Rub down with abrasives compound and polish.Pickling

DESCRIPTION

– Swelling or wrinkling of the paint surface, varying in severity and most often occurring around feathered edges. The underlying paint may break through the topcoat.

109

CAUSE

– Reaction with the underlying surface resulting from the application of nitro- or thermosetting enamels over thermoplastic acrylics or air-drying synthetics.

PREVENTION

Ensure compatibility of materials or that the underlying layer is thoroughly sealed.

REMEDY

– Rub down the affected area, taking care not to uncover any areas which could give rise to the same problem, seal the surface and repaint. In severe cases rub down the affected area to the substrate and repaint.

Panel Faults

DESCRIPTION

– Surface irregularities, typically appearing as ripples, curved, straight or crisscrossed grooves, or jagged or globular protrusions.

110

CAUSE

– Conformation of the paint film to surface defects of the substrate. These may be due to:

a) Press or mould irregularities, poor surface finishing of the substrate, too coarse abrasion by file or disc, weld spatter.

b) Poor or insufficient filling or stopping, incorrect stopper, inadequate flatting.

c) Insufficient application of primer.

d) Applying colour over improperly dried high build primer.

PREVENTION

a) Examine the surface carefully before spraying, and correct any defects and irregularities. Use the correct grades of abrasive, use files or discs correctly, remove all weld spatter.

b) Fill or stop all defects, use the correct stopper, flat down correctly.

c) Apply an adequate thickness of primer and flat to a smooth surface.

d) Allow materials to dry or cure properly.

REMEDY

– Strip paint down to the substrate. Correct all defects, prepare the surface correctly and repaint.

111

Pinholing

DESCRIPTION

– Small cavities, generally less than 1 mm in diameter, occurring over stopper, filler or GRP substrate.

CAUSE

– Absorption of the paint into holes in the substrate. This is due to: a) Air inclusions in GRP resin

b) Inadequate preparation and sealing of the substrate

c) Poor quality filler or stopper

d) Poor mixing of filler, poor application of filler or stopper

112

PREVENTION

a) Heat to above spraying temperature prior to preparation to burst inclusions. Do not heat above 80°C to avoid distortion of the surface.

b) Inspect GRP surfaces and filled or stopped areas carefully. Stop any pinholes, spot prime and flat until smooth before priming the complete surface.

c) Use only recommended materials.

d) Mix filler correctly, apply filler and stopper in thin, smooth layers. Allow to harden fully before applying further layers and before rubbing down.

REMEDY

– Rub down the affected area to the primer, stop any pinholes, spot prime and flat until the surface is smooth, then repaint.

Polishing Marks

113

DESCRIPTION

– Micro-grooves or smears on the surface of the film, typically in a curved or swirling pattern. Underlying layers may show through.

CAUSE

– Abrasive damage to the paint film due to: a) Compounding or polishing the surface before fully hardened

b) excessive pressure or speed of mechanical polisher.

c) Use of too coarse or ammoniacal compound, or incorrect polish, dirty or coarse polishing cloth or mop.

PREVENTION

a) Allow surface to harden fully before compounding or polishing.

b) Use mechanical polishers at minimum pressure and correct speed.

c) Use the correct grade and type of compound and polish, ensure polishing cloths or mop are soft and clean.

REMEDY

– Allow the surface to harden fully, then flat, compound and polish. In severe cases, flat and repaint the surface film.

114

Runs / Sags

DESCRIPTION

– Well defined local thickening of the paint film in the form of a wavy line or shallow, rounded ridges, normally confined to sharply sloping or vertical surfaces.

CAUSE

– Slumping of the paint film due to:a) Excess thickness of application, air pressure too low, fan width too narrow, spray gun too close to the surface or moving too slowly.

b) Use of poor quality or incorrect thinner.

c) Incorrect viscosity of the paint.

d) Air or surface temperature too low.

115

e) Contamination of the underlying surface

PREVENTION

a) Use the correct spraying technique and spray gun settings.

b) Use only recommended thinner.

c) Ensure that the paint is mixed to the correct viscosity.

d) Always spray within the recommended temperatures.

e) Ensure that the surface is scrupulously clean.

REMEDY

– Allow the paint to harden thoroughly, rub down excess paint, flat, compound and polish. In severe cases it may be necessary to rub down and repaint the surface.

– Note: Due to separation of the metal flakes, metallic paints will normally require repainting.

Sand Scratches / Flatting Marks

116

DESCRIPTION

– Surface scratches under the paint film.CAUSE

– Shrinkage of the paint film during drying causes it to follow the contours of any scratches or other finishing marks in the underlying surface. The defect results from:

a) Poor finishing of the underlying surface, abrasives too coarse, inadequate flatting, inadequate stopping.

b) Colour coat applied before the primer is properly hard.

c) Insufficient paint thickness, or a too slow drying rate.

d) Incorrect mixing of paint, use of wrong or poor quality thinner.

PREVENTION

a) Use the correct grade of abrasives, use stopper on any deep scratches, flat the surface to a smooth finish.

b) Ensure that the primer is fully hardened before applying the colour coat.

c) Apply the correct paint thickness, under correct drying conditions.

d) Mix the paint thoroughly, using only recommended thinner.

REMEDY

– If the marks are light it may be sufficient to flat, compound and polish the affected area. In more severe cases the surface must be rubbed down until the marks are removed and then repainted.

117

Scratches / Stone Chips

DESCRIPTION

– Damaged and broken paint film, varying in depth and extent depending on the cause.

CAUSE

a) Impact damage, typically caused by stones thrown up from loose road surfaces, or scratching by sharp objects.

PREVENTION

a) Damage caused on the road may be unavoidable, but care should be taken to protect vehicles in storage, in the paint shop or in transit.

REMEDY

– Rub down the affected area, feather the edges of the chips, restore the level with stopper and repaint.

118

Sinkage

A condition where the topcoat appears to have “sunk” into the substrate. A bit like painting on blotting paper. Poor gloss, scratch marks and a slightly rough surface characterise this condition.

DESCRIPTION

Semi matt, hazy surface, usually extensive and showing minute pores under low magnification. Flatting marks may show on the surface.

CAUSE

Absorption of the gloss coat into the underlying paint - may result from:

a) Failure to seal or pre-coat porous surfaces, failure to spot prime filler or stopper.

b)Incorrect application of primer, excess primer, insufficient, incorrect or poor quality thinner, insufficient stirring.

c)Poor preparation of primer surface, flatting before properly hard, abrasive too coarse, poor flatting.

d) Application of the topcoat before the primer is thoroughly hardened, insufficient colour coats.

PREVENTION

a)Prepare the underlying surface correctly.

b)Apply the correct thickness of primer, use the correct quantity of recommended thinner. Mix primer thoroughly immediately before use.

c)Allow the primer to harden properly before flatting down, use the correct grade of abrasive, flat the surface evenly and smoothly.

119

d)Apply a sufficient number of thin, wet films of colour coat.

REMEDY

Allow the paint to harden fully, flat, compound and polish. In severe cases, flat the affected area and repaint.

Slow Drying / Softness

A condition that is self evident. The paint film is not as hard as it should be.

DESCRIPTION

– The paint film requires an excessive drying period, or fails to harden thoroughly.

CAUSE

– Slow evaporation of solvent from the paint. This may be due to:a) Excessive thickness of the paint film.

b) Poor atmospheric conditions during spraying or drying, coldness, humidity, lack of air movement.

c) Insufficient drying time between coats.

d) Insufficient, poor quality or incorrect thinner.

PREVENTION

a) Apply paint in thin wet films.

b) Ensure adequate warmth and ventilation. Avoid spraying in excessively humid conditions.

c) Allow sufficient drying time between coats.

d) Use the correct amount of recommended thinner.

120

REMEDY

– Move the vehicle to a warm, well ventilated area. Low heat may be applied to improve drying, but care must be exercised to avoid wrinkling.

Solvent Popping

DESCRIPTION

Open topped blisters up to 1mm in diameter on the surface of the most recently applied paint film.

CAUSE

– Air or solvent vapour trapped by fast drying paint forming a skin. This may be due to:

a) poor quality or too fast thinner.

b) excessive film thickness, or insufficient drying time between coats.

c) compressed air pressure too low.

121

d) drying temperature too high, heat source too close to the film, too hot, or applied too soon.

PREVENTION

a) Ensure that the surface is scrupulously clean.

b) Use only recommended thinner.

c) Apply paint in thin, wet films. Allow sufficient drying time between coats.

d) Use correct compressed air pressure.

e) Allow sufficient flash off time before force drying, ensure that the correct drying temperature is not exceeded. Do not allow the heat source to be placed too close to the surface.

REMEDY

– Rub down to a smooth surface and repaint.Water Spotting

122

DESCRIPTION

– Circular marks, normally up to 6mm. in diameter, on the surface of the paint film. The marks are usually lighter in colour than the surrounding surface.

CAUSE

– Water droplets impacting on, and evaporating from the surface. The marks may result from:

a) Exposure of the paint film to rain or water splashes before it has fully hardened.

b) Rain or water splashes on an excessively thick film of wax polish.

PREVENTION

a) Protect paint surfaces from water until fully hardened.

b) Do not allow excessive wax build up on the surface.

REMEDY

– De-wax the affected area, flat lightly and polish, repeating if necessary. In severe cases repaint the topcoat.

123

Wax Incorporation / Retention

DESCRIPTION

– Smears or dull areas in the paint film. The affected areas may feel greasy.

CAUSE

– Absorption of wax into the paint film due to:a) Application of wax polish before the paint has fully hardened.

b) Excessive or incorrect use of polish or compound.

c) Poor polishing technique.

d) Storage of wax protected vehicles under hot conditions.

PREVENTION

a) Allow the surface to harden fully before polishing.

b) Use only recommended products, use as instructed.

124

c) Use correct polishing techniques, ensure that the gloss level is even over the entire surface.

d) Protect stored vehicles from excessive heat.

REMEDY

– Apply a solvent cleaner, followed by polishing with a non-wax polish. Repeat the process until all wax has been bled from the surface, then repolish.

125