Ship Production II

8/8/2019 Ship Production II

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DESIGN FOR PRODUCTION

Design for production produce a design which brings out anacceptable compromise between the production and operationaldemand at the same time it takes into consideration the otherdemand of repair maintenance and lifetime activities.

Various factors to be considered for ship like period during designstage is known as design fors;

The overall objectives of design for production are: To reduce the production cost to a minimum compatible with the

required at design: To enable the design to fulfill its operational function withacceptable reliability and efficiency

FACTORS TO BE CONSIDRED in DESIGN FOR PRODUCTION

: Design intermediates to be made suitable for the productionprocess: Design To be made according to the material available

limitation and suitability of shipyard:Importance are to be given in structural design suitability ofaccurate hull form structural design connections using large no ofidentical components are also to be considered: Optimum utilization of ship yard facilities and ship facilities: Minimization of material usage and work content.: Good acceptability eases of transport storage and assembly Easydesign for the erection of assemblies and components

: Minimize welding and cutting advanced outfitting processes may beadopted: minimize material movement

Design for production Specific examples


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1: Straight line camber instead of parabolic.2: Avoid double curvature plates3: Plates of available max size should be used4: Reduce the amount of welding5: Use simple fabrication method6: maximise the usage of identical thickness plates7: Internal webs are made straight.8: Assembly diagonal such that there is at least one side flat in eachblock

Design for Maintenance

1: Example in case of removing an engine casing is one of the functionsof removing engine parts.2: Double bottom height 2m in time of inspection should have easyaccess to the double bottom.3:Tools design for maintenance make sure that whenever themaintenance required the tools needed for it should be in easyvicinity

4:Double bottom heights5:identification :ALARMS6: Accessibility7: Take out if any particular part is to be repaired then it should beeasily taken out for repair

DESIGN FOR OPERATION

: Comfort: Injury: Vibration fatigue: Accessibility: Doors cofferdam double bottom manhole height should be aparticular height


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DESIGN FOR ABANDONMENT

: Environmental problems should not be there: Removal of wastage.: Hazardous should be minimum at the tie of removal: Design for STANDARDISATION:Reduction of repeated work by using the same drawings equipments,

joints, quality control, Work procedure ,processes planning ,Reduction of labour, Quick ordering, quick acquisition

DISADVANTAGESCannot be used one of the kind

DESIGN FOR WELDING:Base metal selected should not undergo degradation in their physicaland chemical properties likeLoss of toughnessloss of ductility

loss of strengthCorrosion resistanceBimetallic corrosion

Avoid abrupt change in geometry or cross-section to reduce stressconcentration (Eg. Corners of hatch openings Superstructure endings)Avoid excessive welding to minimize welding stressWelding symbols must be specified with non destructive testing

symbols...A detailed welding plan needs to be specified, Welding sequence besuch that the distortion be minimum. It depends on type of weldingused

Prodn design


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1. Design info to be made suitable for pdn process2.design to be made according to material available and limitations &suitability.3.structural design to be given importance4.optimum initialization of crane ,shop facilities5.minimise material usage6.good accessibility and ease of transport $ storage7.components easy to assemble and erect8.elimination or modification of structural component design difficult9.bulbous bow to be made of many pieces

10.hull design to be optimised11.min welding and cutting to be used12. dished plates to be avoided13.avanced outfitting procedures may be adopted

Q: Discuss briefly the importance of QC in ship production?

A: The advantages of employing effective QC in ship building are:1. Defects are detected early and rectification can be carried out at

the most convenient time and in the most economical way.2. Work is reduced in the final stages of hull construction, which isdifficult and costly and takes place in bad working conditions.3. Wasteful work and scrap are reduced.4. Progress of the work becomes steady so that planning andscheduling becomes more effective.5. Analysis of tolerances required at each shape allow the cost ofimproving the process or equipment to be balanced against the

benefits of less frequent correction or rejection of workplaces,thereby helping to establish a long-term procurement policy.44

Welding stds


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In Ship building, tolerances allowed are:For main structural members: 0.15 t or mm whichever is lessFor others:- 0.2 t or mm whichever is less.

In custom built products, the tolerances should be specified in thecontract

Root gap:The root gap of the joint should be as per the welding. Procedure

qualification test. An increase or decrease in root should be rectifiedby suitable methods like gas cutting. grinding, fitting backing strip,

building up of edges by welding, etc.

Bevel angle:A reduction in bevel angle beyond specifications can lead to

penetration problems in welding. An increase in bevel angle willincrease the cost of fabrication by way of increased consumablerequirement, cost for correction of weld distortion etc.

Root face:A reduction in thickness of root face will cause burning the plateedges whereas an increase in thickness of root face can cause lack ofroot fusion - Increased amount of back gouging/chipping cansometimes cause weld distortion

Surface finish of cut edge:Serrations at the cut edges can cause entrapment of slag and lack

of side wall fusion.

Surface condition of the joint:Foreign matters like rust, dust, oil, grease, paint, etc in the weld

joint cause porosity in the weld.


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Welding procedure to be used:The welding procedure to be used in the welding of the joint should

be qualified. Welding procedure specifications and Welding procedureQualification Record should be available for checking.

Welders and Welding operators:Welders and Welding operators to be engaged on the job should be

qualified.

Welding machines and accessories:Welding machine should be in good condition. Accessories like wire

brush, chipping hammers, gouging torches and pro-activities likehelmets gloves etc should be available for production of sound weld.

Critical Path

It is that sequence of activities that decide the total projectduration .Critical path is formed by critical activities. A critical pathconsumes maximum time. A critical path has zero float. The expected

completion dates cannot be met if even one critical activity isdelayed. A dummy activity joining two critical activities is also acritical activity. A critical path reveals those activities which must bemanipulated by some means or the other if the scheduled completiondates are to be met.

Difference between PERT and CPM.

The fundamental network of PERT and CPM are though identical,yet there are certain differences in details as given:

PERT:


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1. A probabilistic model with uncertainty in activity duration.Expected time is calculated from t0,tm and tp.2. An event oriented approach3. PERT terminology uses words like network diagram, events andslack.4. The use of dummy activities is required for representing theproper sequencing.5. Pert basically does not demarcate between critical and non criticalactivities.6. It finds applications in projects where resources are always madeavailable as and when required.

7. Especially suitable in defense projects and R&D where activitytimes cannot be reliably predicted.

CPM:1.A deterministic model with well known activity times based uponpast experience. It assumes that ,the expected time is actually thetime taken.2.An activity oriented system.

3.CPM terminology employs words like arrow diagram, nodes and float.4.The use of dummy activities is not necessary. The arrow diagramthus becomes slightly simpler.5.CPM marks critical activities.6.It is employed to those projects where minimum overall costs is ofprimary importance. There is better utilization of resources.7.Especially suitable for problems in industrial setting, plantmaintenance, civil construction projects etc.

Technique:

CPM employs the following steps for accomplishing a projectplanning.1. Break down the project into various activities systematically.2. Label all activities.


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3. Arrange all the activities in a logical sequence.4. Construct the arrow diagram.5. Number all the nodes and activities.6. Find the time for each activity.7. Mark the activity times on the arrow diagram.8. Calculate the early and late, starting and finishing times.9. Tabulate various times and mark EST and LFT on the arrowdiagram.10. Calculate the total float for each activity.11. Identify the critical activities and critical paths on the arrowdiagram.

12. Calculate the total project duration.13. If it is intended to reduce the total project duration, crash thecritical activities of the network.14. Optimise the cost.15. Update the network.16. Smooth the network resources.

PROCESS PLANNING:It is the: Systematic determination of methods by which a product (ship) is tobe manufactured, economically and on schedule.: Function which establishes processes and process parameters to beused to convert the raw materials into finished product.

: Intermediate stage between designing and manufacturing

MAIN INFORMATION FOR PROCESS PLANNING:: Product specifications and quantity of work: Quantity of work to be completed.: Availability of raw materials, tools, equipments, personnel.: Sequence of production


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: Standard time.: Machines on which process will be performed.: Schedule of the process.

PROCESS PLANNING PROCEDURE:1)Preparation of working drawing showing geometrical shape,dimensions, tolerances, type of surface finish, surface coating,information for inspection, identification code, materialspecifications.2) Make or buy decision.3) Process selection based on level of automation, kind of work flow,

quality level, delivery urgencies. etc.4) Machine capacity and machine selection.5) Selection of materials, jigs, fixtures, auxiliary equipments.6) Prepare documents like operation and route sheets9

Planning and production control

A ship building process is1. Complex2. Long cycle of operation

The most important objective in ship building is maintaining thedeliver schedule in view of the above point.Proper planning is essential to determine the many sequential & inter

related operations and activities for orderly ship construction

PLANNING ACTIVITIES

1 long term (2-3years or more)2 medium terms (monthly, I monthly, 6 monthly)3 short terms (Day to day)


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Long term

constitute master plan of shipsmaster plan contains the master schedule which is circulated fromthe planning dept to various other important depts. of the ship yards

The complex nature of ship building makes good planning and prodcontrol very important because ship building is a capital intensiveactivity with large capital investment in plant and may therefore high

equipment utilization with high output is an essential requirement.Also technique of advanced outfitting can not be successfullyimplemented without a high level of plant output .good PPC also helpsin timely completion of work and maintenance of delivery schedule.this is an important factor as far as the reputation of the shipbuilder is concerned

in some respects planning and PC has become a little easier with the

introduction of flow production and the standardization of shipsbeing built computers have made the task of planning and PC alsoeasier and more effective the planning may be done in 3 stages, longmedium and short term at various levels inside the ship yard. The longterm plan contains the cardinal dates eg signing of the contract, keellaying, launching, test and trials, delivery.

this is then broken down into six monthly, 3 monthly,monthly,weekly

and daily activities Production control is based on progress reportingthere are team of production controllers who monitor the progress ofwork on a day to day or weekly basis and report the bottlenecks tothe managements to take the corrective action


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PLANNING

divided into...1. STRATEGIC PLANNINGa. profit planb. sales plan

2. TECHNICAL PLANNINGa. principal extents (keel lying)b.block definitionc.advanced outfitting

3.PRODUCTION PLANNINGa.Drawing scheduleb.Material planc.Welding pland.assembly plan

4.IMPLEMENTATION PLANNING

a.Shop scheduleb.Work par

Levels of planning

1.Basic planning2.Detailed planning ..weight and size of unit. mode of outfitting.material requisite plan

3.Working detailed plan ..Schedules (PERT CMM).Producton drawingstandard4.work intensive planning .material issue

Effectiveness of planning


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1 communication2 satisfy owners & classification societies requirement3 Minimise design change4 preperation of standard5 accuracy and work instruction plan6 effective accuracy control measures7 hull construction schedule preparation8 Preparation of process lines

PRODUCTION SCHEDULE

Once the contract plans are released and basic planning is over, hullconstruction planning group initiates detailed planning in two phases:1)department level planning/scheduling2)shop level planning/schedulingScheduling can be defined simply as the allocation of resources and timefor various production units to closely match with the project completiondates and budget estimates. Basically it determines when andwhere,what is to be done.

There are four distinct stages to this:

I)Basic schedulingShip building master scheduling-relates all cardinal dates for allships/projects to be built in a specific period.

Hull erection master scheduling1)Responsibilty of the production engineer

2)co-ordinates with onboard outfit schedules3)main input are block defintion plan4)emphasis on outfit of large macinery like diesel generator whichhave to be fitted before any other block in ER.This requires treatingsuch an item as a seprater block.


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Shipbuilding activity timing schedule1)using block predefinition plan,erection master schedule,outfitpalns,outfit master schedule2)bar chart showing the required time for each process right from

yard plan issue to erection3)provides dates for erection,commence and completion of hullassembly issue of hull construction drawing,acquistion ofmaterials,major outfit on board dates4)it is the basis of all the schedules

II)Major scheduling

Made from erection master schedule.It shows:a)shortest practical period of erectionb)easiest erection sequencec)duration required for fitting and aligning blocksd)date for erectione)daily m/h requirements for fitters and welders

IIa)Assembly master schedule1)derived from EMS,s/b activity timing,design maaster sschedule2)forecasted work is depicted using welding length for assembly3)duration required for assembly of each block for all ships

IIb)Integrated schedule1)i/p from o/f dpt,o/f shop master schedule2)shop schedules are updated every two months together with IIa

III)Working scheduling include:1)assembly,subassembly,part fabrication,monthly schedule2)yard plan,mold loft issue curves


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Accuracy control

the use of statical principles to monitor,control and continouslyimprove ship building design details,planning and work methods tomaximize productivity.It also provides a quantitative feed back loopb/w production,planning,design and engineering

Statical principles1)nothing called absolute accuracy2)variations from specified dimensions are always iminent3)fundamental basis is the theory of probability

4)the dimensions vary from component to component due to inherentmachines characteristics,envt. conditions and workers expertise5)any important continous probablity distribution is a normaldistribution or Guassian distribution6)it is the plot of the variation observed in the product

ISM

The purpose of this Code is to provide an international standard forthe safe management and operation of ships and for pollutionprevention.Recognizing that no two shipping companies or ship owners are thesame, and that ships operate under a wide range of differentconditions, the Code is based on general principles and objectives.Objectives1. The objectives of the Code are to ensure safety at sea, prevention

of human injury or loss of life, and avoidance of damage to theenvironment, in particular to the marine environment and to property.

2.Safety management objectives of the Company should,.1 provide for safe practices in ship operation and a safe workingenvironment;


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.2 establish safeguards against all identified risks; and

.3 continuously improve safety management skills of personnel ashoreand aboard ships, including preparing for emergencies related both tosafety and environmental protection.3 The safety management system should ensure:.1 compliance with mandatory rules and regulations; and.2 that applicable codes, guidelines and standards recommended bythe Organization, Administrations, classification societies andmaritime industry organizations are taken into account.

Application

The requirements of this Code may be applied to all ships.Functional requirements for a safety management systemRequirements of safety management system of companies1 a safety and environmental-protection policy;2 instructions and procedures to ensure safe operation of ships andprotection of the environment in compliance with relevantinternational and flag State legislation;3 defined levels of authority and lines of communication between, and

amongst, shore and shipboard personnel;4 procedures for reporting accidents and non-conformities with theprovisions of this Code;5 procedures to prepare for and respond to emergency situations; and6 procedures for internal audits and management reviews.

AutoCAD draftingIt is a tool for designing .Here 2d and 3d designing is possible 2d

design gives an outline of the structure which we are meant toproduce 3D will give the overall view of the product prototype can beavoided. By using this tool a client is able to see his product beforeconstruction & suggest improvements if needed it is more accurate &more flexible is possible using this structural; analysis can be done sothat drawings can be generated in a small time using plotters


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tribone modelling

it is software meant for modelingusing his new designs can be developed after this the surface of

design is faired & then patchedafter this we can generate the hull for modelingwe can take parts from the geometry macro if not in geometry macrowe can produce in geometry macro we can model the whole shipafter modelling the ships the production information can be directly

taken into the prod uction site

automaic nesting is also done16

CAD::

it includes tools to perform the overall technical definition of theship but does not include engineering details or acquisition orfabrication studiesCAE::

it includes tasks to perform calculations & to develop designdocuments and procurement specifications for main equipments andmaterialsCAM::

it includes tools to obtain all the information necessary to procurethe remaining equipment & materials and to fabricate and erect theship.The contract class and detail designs of commercial ships are

performed with CAD|CAE|CAM soft wares respectively

ADVANTAGES OF CAD/CAM SYSTEMS:

They are:Ability to produce concept and feasibility ship design studies quicklyand accurately than any conventional method


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:Ability to rapidly evaluate design option and optimization.:Ability to 'lock in' and assemble successful design experiences andprocedures.:Ability to add attractive design to the database for future use.:Ability to interface with computer graphics.:Ability to transfer data in digital form between design andmanufacturing designs of the shipyard.:Ability to employ shipyard standards.:Ability to assemble and 'lock in' successful building strategies andprocedures.

INPUTS FOR AN EFFICIENT CAD/CAM::numerical data on past design:geometrical data on past design, hull forms etc.:weight and space scaling laws.:resistance and propulsion data.:sea route:cost data:sea spectrum

:Strength and structural data:Engine performance data:typical block plan:typical o/f plans:material list(MLC, MLS):shipyard standards

The difference between corporate planing and production planning

a. OVERVIEWthere are two different overview for the corporate planning &production planning the corporate planning has the total yardoverview. The yard overview is essentially the sum of all individual


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projects The product planing refer to only the individual constructionor repair jobs.

b.Time bound planning

in case of the corporate planning planning is done keeping in mind thelong term consideration including market workload employmentforecasting whereas in production planning is done keeping in mind thetime a project is started till it is completed

c.Objective

Corporate policy of a ship yard aims at improving the occupation ratetake maximum numbers of the orders and to have maximum businessover a period of time where production planning aims at reducing thecost of production improves the flow of work and the completion ofwork

LEVEL OF PEOPLE

level of people that are involved in case of corporate planning are atthe topmost level of managers and employs the heads of thedepartments and units where the people involves for the design forproduction involves people only at the production level.

CHANGES AND MODIFICATIONS

often it is seen that the changes to production planning are made ifthey are found not to be capable with the schedule but the corporatepolicy does not change very easily as it involves lot off ground workand effort to reach it.


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SHIPBUILDING POLICY & BUILDING STRATERGY

Over view the shipbuilding policy consists of the shipyards plans tomake or produce a certain kind of ship over a period of time where asbuild strategy is shipyard capacity standards and performances andcombines those with contract or customer requirements

Application:

Built design helps to provide input to design and include strategic

tactical and detailed production engg and product analysis where asshipbuilding policy gives an ideas as whole to the complete yard ofgoals of production and further output

shipbuilding policy is utilized by complete yard and is used for theworking of each department where as the build strategy can be usedonly for the input of production and design departmentit has no effect in corporate planning and other departments

time bound planning :shipbuilding policy is usually applied for a long time over a period oftime during which the ships are to be built say (5-6 years) here asbuild strategy is to be taken only till the time the ship is to berepaired or built in the YARD.

Q: Explain in detail the principle of flow line production in SB?

A: Principles of flow line production in SB:-1. Various stages of ship building are sequentially carried out.2. These are work stations for each stage of production where

different jobs are undertaken. The jobs undertaken at a particularworkstation may be similar in nature. These areas or workshops are


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equipped with many tools, and equipment to do such jobs and manned byspecially trained personnel.3. Repetitive operations may be carried out at workstations.4. The system is highly suited to producing idle items in large

quantities, i.e. mass production.5. The production system is suitable for high production loads.

The traditional production system shipbuilding is craft oriented. inthis, diver products are made in a single shop, make scheduling of theproduction process difficult. Level of shop loading is low and sequencework unpredictable.

The flow line production, on the other hand has the following

features:-1. The shipbuilding process is divided into many activities such as EnggWork, steel work, and electrical work, which are independent of theother. Each of these major activities further broken down in productionstages as shown below. These stages are sequentially completed

2. There are separate workstations where different specificallyidentified jobs are undertaken.

3. Repetitive operations can be done smoothly4. Suited to mass production5. High level of shop loading achieved6. Work stations may be classified based on:

(a) Similarity of procedure and routine(b) Operating line(c) Size, shape and dimensions of parts of the product

Advantages:-1. High degree of control and supervision is possible.2. Logical flow of materials and components within and between work

stations.3. QC methods can be applied conveniently4. Scheduling and collection of work performance data is simple.


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5. High degree of utilisation of infrastructural facilities.6. Need for highly specialised tradesmen is reduced.

Disadvantages:1. Less flexibility2. Disruption in one part will shut down the system3. Monotonous work.

FLOW PROCESS CHARTS:

They are1)Bar chart

2)Curve chart3)Gantt chart4)Mechanical chart

BAR CHART:(1 picture)

Gantt chart:

Gantt charts are a project planning tool that can be used torepresent the timing of tasks required to complete a project. BecauseGantt charts are simple to understand and easy to construct, theyare used by most project managers for all but the most complexprojects.In a Gantt chart, each task takes up one row. Dates run along the topin increments of days, weeks or months, depending on the total lengthof the project. The expected time for each task is represented by a

horizontal bar whose left end marks the expected beginning of thetask and whose right end marks the expected completion date.As the project progresses, the chart is updated by filling accordingto the progress of workThis way, one can get a quick reading of project progress


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In constructing a Gantt chart, keep the tasks to a manageable number(not more than 15 or 20) so that the chart fits on a single page. Morecomplex projects may need subordinate charts

For team projects, it often helps to have an additional columncontaining numbers or initials which identify who on the team isresponsible for the task.

Machine chart

:It is modified bar chart

: In this load is marked against a time scale.:one horizontal bar on line allocated to each DEPARTMENT.

It displays ::plans for future:progress on present operations:past achievements:relationship of overall variables

:delays and causes:work progress till any day.It is of 2 types:(I)Order control chart: Here time is listed in horizontal axis andorders along vertical axis .(1 picture)

(ii)Machine load chart: Here time is along horizontal axis and m/calong vertical axis.

(1 picture)

MACHINE LOAD CHART

b)Making a report of progress::fixed interval on every stage


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:report must contain job identification ofc)Transmission of report::hard copy:oral system:electronic system.d)corrective measures taken.

GROUP TECHNOLOGY

Group technology is also called family manufacture, started as anoutgrowth of an attempt to develop a more efficient system of

classification and coding for the use in management of industrialprocesses. A classification system is essential to the organization ofdata in order to facilitate analysis and synthesis, formulation ofhypothesis,experimentation,deduction and finally generalization topractical application.Group technology is also called cellular manufacture.

Work flow (called virtual work flow) involves movement of the peoplefrom one place to another(real flow - work piece from station to

station).Same group of people moves with the product .Main aim is toprevent people waiting (machines may wait).Concept of zones and stagesis applied.

Group technology has been most extensively used in the machiningindustry, where the cell consists of a grouped number of machines andpeople who operate them .The operators are trained to operate all themachines .A major objective of Group Technology is to reduce inventory

of work in process to only what is needed .Setup time in the cell isminimized, because cells are designed so that machines need only someadjustments rather than completely reset.

An additional benefit is that the job satisfaction is high in GroupTechnology. When a cell is loaded, workers only see the individual


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product emerge within a short period of time .The productivity is higherin group technology.

The group is the basic production unit of zone or product orientedship construction, in which the total integration of all departments is theshipyard.

In ship building, cell consists of a crew of workers whose mostsophisticated piece of equipment is a spanner wrench or a simple arcwelder .In ship building, a cell or group is responsible for completing allaspects of a given block or unit including piping, ducting, painting etc. Ina conventional type of manufacturing the idleness is higher .The workers

have to wait .In order to complete one product some times, the workersmay need specific task to be completed .One goes to find the part andrest wait .eg: sometimes drawing may not be available if the ship isdivided into small zones(geographical areas), then the master schedulenever has to be concerned with many interface between any of theentire system on the ship .These zones represent the output of a GroupTechnology or group. The cell is then loaded with all the resourcesnecessary for the completion of some manageable work package .Such a

work package may include a portion of the fire mains system, along withventilation ducts, electric circuits etc.

Advantages of Group Technologies

1) Work content estimation is more efficient, since it differentiatesbetween kinds of jobs (rather than just based on steel weight)2) Accuracy is greater

3) Many similar activities can be clubbed together (eg: a singlefoundation for many equipments rather than separate seating for each)

IHOP:

The main components of this approach are


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1)HBCM: where in hull parts, SA ,blocks are manufactured inaccordance. The principles of GT(family manufacturer) in org prodlines(process lanes or work flows).The blocks are designed such that::for block assembly; They are assignable to or of the minimum no. ofwork package groups considering similarities in problem area and needto minimise variations in working times.:for block erection; they are table configurations requiring temporarysupport or reinforcement and hence minimum working time.:for o/f and painting; sized so that maximum accessibility to allregions is possible.

2)ZOFM: which makes possible eficiency gaining through concurrenthull construction and o/f.:provides precise zones by stage control.There are 3 basic stages::on-unit o/f: fitting assembled in-house independent of hul structure.:on-block o/f: fitting arrangements on ceiling of block is upside downin one zone while on its deck is another zone.:on-board o/f: fittings during erection and after building zones areholds, tanks, ER etc.

3)ZPTM: surface preparation and painting are treated as integralaspect of overall construction process.:It transfers much of the painting work in a building dock topreceding manufacturing levels like an assembly process.

4)PPFM: Classifies pipe pieces into groups having design andmanufacturing attributes similar to make batch production possible.

5)PWBS: This is the classification system which facilitates the abovementioned division of work and their integration by defining interimproducts(parts, sub assembly, assembly, blocks).:This is done by co:ordinated work flow.


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ISO 9000 Quality system:

: International Organisation for Standardisation, Geneva,Switzerland: ISO 9000 evolved from the standardisation of QA systems of

several nations.

Characteristics:: can be implemented in any type or size of org.

: independent of produce, commodity: has international acceptance and recognition: ensures consistent improvement in quality.

1. ISO 8402: 1986 quality : vocabulary2. ISO 9000: 1987 qual man and QA stds: guidelines for selection anduse of 150 standards3. ISO 9001: 1987 qual systems : model for quality assurance in

design, development, production,installation,and servicing

4. ISO 9002: 1987 qual sys : model for quality assurance inproduction and installation5. ISO 9003: 1987 qual sys : model for quality assurance in inspectionand test6. ISO 9004: provides guidelines for technical, administrative andhuman factors affecting the quality of production or services.

Emphasis on satisfaction of customer's needs, establishment offunctions, responsibilities and importance of assessing potential risksand benefits.

: used for internal quality assurance: deals with qual related cost, qual in marketing, qual in

specific, qual in procurement, qual in production documentation, etc.


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Steps for ISO 9000 classification:1. Quality assurance training2. Task force3. Analyse existing procedures and enforce corrective action4. Design and develop standard procedures5. Documentations : Quality manual

: Quality procedure: Work instructions

6. Implement quality systems7. Audit 6

8. Audit 6 from 3rd party9. Apply classification and maintain system when certified.

ISO 9000:: Credibility passport for international standard: Designing: Developing: Installation

: Production: Servicing

Benefits:: International recognition of ability, credibility, expertise: Provides competitive edge: Climate for consistent improvement in quality: Reduces waste and repairs

: Maintains streamlined records, material handling, storage: Maintains process quality: Insures benefits

Limitations:: Demand of resources for implementation


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: Registration is expensive: Requires upgrading and test facilities: Cost is increased

Production control:: for monitoring cost and schedule adherence: responsible for issuing manhour budgets based on which progress

may be evaluated.: monitoring can be based on the following three parameters:

1. Manhour expenditures:

: applies to all work process: measure of manpower index

2. Production progress:: uses different parameters like weight, length of weld, laid cablelength per unit time to determine the progress index: based on it shifting work, over time, subcontract involvement may bedecided upon.

3. Productivity indices:: utilises both m/p expended and also production progress parameters: there are plotted relative to established standards of efficiencybased on past experience: any curve above the efficiency reference above average rate of m/nexpend.

Lofting:

The full-size mold loft had a large, well-lighted, clear floor having asmooth wood surface. The fairing of lines from the preliminary lines andoffsets were done using the full-size beam and depth of the ship buthaving the length contracted to 1/4th -size due to space limitations.After the lines had been faired, the body plan was laid down, the framelines were run in, and the final mold loft offsets were picked off.


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Templates were made of different materials like basswood, plywood,Masonite, and heavy waxed paper. The templates were marked withnecessary information such as plate edges, frame lines and check linesfor accuracy of the dimensions. This was transferred to the plate byscribing or centre-punching.

Optical lofting:This consists of drawing structural members 1/10 full size,

photographing the drawing on a glass negative to about 1/140 full sizeand then projecting the negative image to a full size on a steel plate.

Optical lofting requires a much smaller working space than that

required for a full scale lofting. The high degree of accuracy requiresmagnifying glasses, special vernier scales, etc. The body plan is drawnwith fine-line pens on a smooth, flat table, or on drafting film. The inkdrawings, most of which are tracings of portions of the lay downs, arephotographed on a glass negative which can then be used to projectlayout information onto the plate.

NC tapes can be prepared by using 1/10 scale information and adigitizer. A digitizer is a manually operated device for converting points

along any line into numerical data for use in the preparation of NC tapes.This method of preparing tapes is much hazardous than the method thatemploys direct computer-aided lofting through numerical detailing.

Computer-aided lofting: The use of computers to define lines of aship and structural parts developed rapidly during the 1960's and 70's.During this period various combinations of optical lofting andcomputerized lofting were used to define the parts.

Computerized lofting requires the use of various items of computerhardware to handle the software, which consists of program modulestailored to produce the output information.

Computer software systems cover all phases of lofting from thedevelopment of the ship's lines to the production of NC tapes in additionto a variety of supplementary design and fabrication information. These


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systems require special talented personnel. Even though attempts havebeen made in some systems to simplify the programming so that lessskilled personnel can be used to model portions of certain programs, theoverall personnel requirements in both of the above mentioned areasbecome increasingly critical to the success of the computer applicationsas the programs expend their coverage.

a. Fairing of lines:The programming for this module fairs the lines of the vessel from

offsets taken from preliminary lines and generates a database. Normally20 stations are used and the the computer fairs the lines between the

stations. It should be noted that the preliminary lines should beaccurate.If only a preliminary type of lines were desired, the computer can

produce input from very rough input, but the output lines would not beconsidered satisfactory for accurate hull surface development.

The resulting mathematical curves are faired using an iterationprocess. if necessary, the position of the station data points may have tobe moved slightly by a skilled operator using the programming to ease

the strain, or curvature, in the beam a minimum amount.Before computer fairing begins, the controlling boundary of the hullas required by the program must be determined. These bounds usuallyinvolve bow and stern ending points, side and bottom tangents, and decklines. After each step in the fairing process, a drawing of stations anddiagonals can be requested by the user to ensure that the program andthe method of using it are functioning properly. On completion of fairing,lines drawing can be prepared. The final frame and waterline offsets are

then routinely tabulated as part of the computer output.One of the advantages of a computerised lines program is that a

variety of hulls can be developed from one basic hull.

b. Body plan:


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To define traces of decks, longitudinals, girders, and seam sightedges, the draftsman must specify a number of points on the associatedtrace along the length of the ship.

Material list

MATERIAL LIST BY SYSTEM (MLS)list of materials required for construction of a ship board outfit system

MATERIAL LIST FOR COMPONENTS (MLC)a list of materials required for construction of outfit components other

than pipe

MATERIALS LIFE FOR FITTING (MLF)material list of all outfit components required by pallet

MATERIAL LIST for pipe (MLP)A list of materials for manufacture of pipe pieces

The lists that are available are such that bulk of planning data on suchlist is immediately available for reuse.

These lists are readily identifiable material requirement formats formaterial control and function.Materials on material list for systems (MLS) are ultimately incorporatedon material list for pallets (MLP) either directly or as component forcustom manufactured.MLP and MLC are listed in their new identities as

custom manufactured item on material list for pallet

A pallet is a group of outfit materials necessary to perform a definedincrement of work which is identified by MLF.The first thing that is developed is the material list for the system thusas the materials of the pallet involve the list all upgraded.


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The use of computer or the machine are used to upgrade the materiallists maintenance of material list is perhaps the most importantcomputer applicationNumerical control:

programmable automation in which the process is controlled bynumbers, letters and symbols. In NC, the numbers from a program ofinstructions designed for a particular work part or job. When the jobchanges, the prog of instructions are changed. this capability to changethe program for each new job is what gives NC its flexibility. it is mucheasier to write new prog than to make major changes in the production

equipment.NC technology has been applied to a wide variety of applications,including drafting, assembly, inspection, sheet metal press-working andspot welding.

Basic Components:it consists of three basic components:

1. prog of instructions

2. controller unit or the machine control unit.3. machine tool or other controlled process.

NC procedure:following steps must be accomplished:

1. Process planning:work part drawing must be interpreted in terms of manufacturing

process to be used. it concerns making the route sheet sequence of the

operation to be done.2. Part programming:

programming the process for job completion is done next. There aretwo ways to program the NC. They are:

Manual part programmingComputer aided part programming


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3. Tape preparation:A punched tape is prepared from the part programmer's NC process

plan.4. Tape verification:

For this the program is run and tool movements plotted on paper. Attimes it may require 3-4 trials before the tape is correct and ready touse.5. Production:

Actual use of NC tape.

NC motion control systems:

There are three basic types of motion control system:1. Point To Point (PTP)2. Straight cut3. Contouring

1. PTP:The objective is to move the cutting tool to a predefined location.

The speed and path are not important. e.g. NC drill presses. They are thesimplest and the least expensive.

2. Straight Cut:In this the movement of the tool is parallel to one of the major axesat a controlled rate for machining. Angular cuts are not possible. Thismachine can also make PTP movements.3. Contouring:

Capable of performing both PTP and straight cut. Also calledcontinuous path m/c. They are the most complex, flexible and expensivetypes of m/c tool controls.

Application of NC:MillingDrilling and related processes.BoringTurning


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GrindingSawing

Most appropriate jobs for NC:1. Parts are processed frequently and in small lot sizes.2. The part geometry is complex.3. Many operations must be performed on the part in its processing.4. Much metal needs to be removed.5. Engineering design carnages are likely.6. Close tolerances must be held on the work part7. It is an expensive part where mistakes in processing would be costly.

8. The part requires 100% inspection.

Range of potential applications of NC:Presswork m/c toolsWelding m/cinspection m/cautomatic draftingAssembly m/c

tube bendingflame cuttingplasma arc cuttingautomated knitting m/ccloth cuttingautomatic rivetingwire wrap m/c

Advantages of NC:1. Reduced non productive time:

Reduces no of setups, less time in setting up, reduced work piecehandling time, automatic tool changes etc.2. Reduced fixturing:

NC fixtures are simpler and cheaper to fabricate.


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3. Reduced manufacturing lead time:Since jobs are set up quickly with NC and fewer setups required,

lead time is reduced.4. Greater manufacturing flexibility:

It is easy to adapt to ED changes, alterations of productionschedules, change over in jobs etc. with NC5. Improved QC:

Produces parts with greater accuracy, reduced scrap and lowerinspection requirements.6. Reduced inventory7. Reduced floor space requirement.

Disadvantages of NC:1. Higher investment cost.2. Higher maintenance cost.3. Finding and/or NC personnel.

Pallets

it is the basis for the control of work and main communication link -can

be viewed as empty buckets filled with various software and hardwareitems. each of it includes info including work instruction schedules worklocations material lists resources including materials tools facilities andmanpower .Each pallet is defined filled with necessary info andresources and delivered to proper work sites at proper time. Work isthen performed and the resulting interim product is produced ..

:Pallets thus represent work packages that are identified by zone/

problem area /stage and provide production with all the info andresources needed for exactly a unit of work

:Various pallet coding systems have been developed to facilitate the useof pallet concept by design material control and production..


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2) Outfit designs advice hull str group of o/f requirements forpenetration and reinforcements in structure Also o/f production processcommunicate with hull const Prodn engineers about requirements for o/fon-block or on-board

3)Also communication is shared between o/f design hull design at theprocurement dept..

Plant location:The location n of the plant has a direct influence on the cost as of

production and on the effectiveness of marketing. Since a company

remains in that location for many years, errors in decision making in theplant location will lead to long term problems. Plant location is of vitalimportance in production-system design. It affects the cost of shippingraw materials and finished products, costs of operations, includinglabour, taxes, construction, land, utilities, power and many other factors.It affects expansion potential. These effects, in some situations, canspell the difference between success and failure companies over the longrun.

The following are the factors which influence the selection of plantlocation:1. Regional considerations2. Community3. Site selection

1. Regional considerations:

a. The location of markets:In a plant location decision, locating plants near markets for their

products and services,is ideal.

Factors considered should be:- Transportation cost


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- Perishability- Bulkiness- Heaviness- Fragility

b. The location of materials:The various inputs of production systems are raw materials,

supplies, semi-finished goods,parts, equipments and tools. Location of these materials is important

for plant locationdecisions.

c. Transportation facilities:

Adequate transportation facilities are essential for the economicaloperations ofproduction systems of transportation facilities available are:

- Water transport: Almost all major industrial cities are located on

important waterways. it'sthe least costly form of transportation per ton-km. Companies which

produce or buy heavy,

bulky and low-value-per ton commodities still consider watertransport an important factorin locating plants.

- Railroad: Railroads add a great deal of flexibility to transportationnetwork. The cost per

ton-km is greater than that of water transport.- Trucks: These have an advantage over railroads in terms of more

flexibility. Over many

alternative routes, trucks can be moved more easily. The arrival anddeparture times are

also more flexible than railroads.- Pipelines: These are used extensively for the transport of natural

gas and petroleum.


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Pipelines are laid in fixed locations. Just like water transport,pipelines have the

advantage of low cost per ton-km.- Airlines: They are the fastest type of transport. but the cost per

ton-km is more expensive.But airline transport is also considered by some companies. For

example, precision-partscompanies which provide quick delivery of replacement parts to

companies.d. Labour supply:

One of the important inputs in production systems is manpower.

Some of the labour-relatedquestions are:- number of potential employees available- their levels of skill and education- productivity of labour force- cost of labour and fringe benefits involved- cost of living as related to labour costs, etc.

e. Climate:

There are two distinct needs of companies in terms of climate.First, the climate should bemild enough, so that the employees remain in a certain region. Second,

some industries requirecertain types of climate for production. For example, in the

agriculture business, someproducts need dry climate and damp climate for others.

2. The choice of community:The next step in selecting plant location involves the choice of a

particular communitywithin the region selected. Some of the factors which affect the

decision are:- Managerial preferences


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- Community facilities- Community attitudes- Government and taxation- Availability of sites- Financing and other inducements

Many of the plants are located in particular communities just becauseof the ties with the

community and the management.Community facilities include the living facilities for the employees

such as schools, shopping

and medical facilities, residential housing, recreational opportunities,police and fireprotection cultural opportunities and so forth.

Community government and taxation represent factors which tend tochange over the years. So the

plant location decisions should be based on the current situation.

Some communities offer even financial inducements to companies toinfluence them to buildplants in their areas.

3. The choice of site:The final decision concerns the choice of a particular site within a

community. For this thefollowing should be investigated:

- size of the site- drainage and soil conditions- water supplies- utilities such as electricity, natural gas, sewer systems.- waste disposal and environmental considerations- transportation facilities


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- land and development costs

Sources of information in plant location:The selection of a plant location is very complex task. Once the

information is gathered, the above mentioned factors can be discussed.There are several types of organisations that assist managers in theirplant location decision making. Most states have industrial developmentagencies to help industries in locating a site, since such industries are asource of tax revenue.

Methods for analysing the plant location decision:

For arriving at a location decision, managers may use technique whichare not influenced by personal bias. In attempting to weigh the otherfactors against one another, two methods are generally used:

Rating plan: In this, weights are assigned to each of the factors thatshould be considered. For this, first a list must be made of theimportant factors that have a say in the decision, the factors are ratedby giving points to the individual factors. The factor deemed most

important is given the highest weight and each of the other a lesseramount.

Cost analysis: As an aid in evaluating plant location, estimates should bemade for all costs entering into the operation of the plant in each of thelocations. This estimate should cover the initial cost of the physicalfacilities, raw materials, manufacture and the cost of distribution. Afterthe determination of each of these costs, the unit cost for

manufacturing the product in each of the locations can be reckoned andmay be used to aid in deciding on the optimum location.

PRODUCT WORK BREAK DOWN STRUCTURE:


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Theory management approach must specify, what is to be done,where is to be done, when is to be done and what resources are to beapplied .This specification generally takes the form of division of thetotal process into components parts .The system by which thesecomponents are subdivided in order to control the process is called awork break down structure.

Two types of work break down structure are there:a) system oriented work break down structureb) product oriented work break down structure

1) System based W.B.S

System based work break down structure is the traditional approachof division of the work on the basis of systems.As per system based work break down structure, the ship deign

process can be divided as:

System oriented work break down structure areused for initial estimates and early design shape .They are notappropriate for planning, scheduling and executing a zone oriented

manufacturing process.Each major groups are hierarchically subdivided into subgroups andthen to elements.For example,group : hull structureelement : overall arrangement : structural drawing

subgroup: hull structural bulkheads

element : longitudinal bulkheads and transverse bulkheads

Disadvantages

1. System wise splitting of work is highly sequential


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2. Working in isolation : that is no communication between twodepartments/systems in system

oriented work break down system3. Less sharing of responsibility4. Time consumed is more since the nature is sequential5. Information handling will be difficult6. Introduction of Modern Production Methodologies is difficult7. Concurrent engineering cannot be applied8. Experts required for each aspect .Role of expertise is more thangeneral skill in S.W.B.S

e.g.: Ballast pump

P.W.B.S::Developed in U.S.A in 1920's and applied in ship building in the 80's:The classification scheme to subdivide works in accordance withinterim product view is called product oriented work break downstructure

In this type of system parts and subassemblies are grouped bycommon permanent characteristics and classified by both design andmanufacturing attribute .The classification system typically specifies

parameters such as forms, dimensions, tolerance, material and typesand complexity of machinery operation.For example the "cargo hold block" : steel, piping, electrical and deck

All functional systems are incorporated in a product .Here the cargohold block is the final product .In this product all the systems neededfor cargo hold will be installed and final product will be cargo holdblock.P.W.B.S first divide the ship building process into three basic type ofwork:a) Hull constructionb) Outfittingc) Painting


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These three types of works are further subdivided into fabricationand assembly classification which are normally associated only withhull construction and outfitting .Within the painting classification,fabrication applies to the manufacture or preparation of paint andassembly means its application(diag 4)

S.W.B.S : outfitting cable + electrical + machinery + structuralP.W.B.S : engine room or auxiliary E.B

Advantages

1.Effective information handling2.Methods such as advanced outfitting can be implementedeffectively3.Reduction in time production since no sequential activity4.Improves the working condition5.Well defined zone or stages and responsibility sharing6.No cross communication .Main communication between closedproduct

7. Since similar products are grouped together, some advantages ofmass production can be achieved

Potential problems or disadvantages:

1.Contradiction may occur .This can actually be minimized byoptimization .Hence CAD/CAM is necessary for implementing P.W.B.S.2.All quality related problems will be shifted to the joining point

.Quality of one product should be exactly same as the adjacentproduct .For this purpose accuracy control is required.(Cross functionability)it is found that a team of 5 to 6 persons aremost efficient (1 from hull,1 engineering etc). There arecorresponding groups in design, production, planning etc.


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P.W.B.S divides the ship building process into three, namely: hullconstruction,outfitting,painting(diag 5)

P.W.B.S classify the interim products in accordance with theirneed for resources,i.e material, manpower, facilities and expenses.e.g::Common parameters to different structural panels regardless oftheir location in ships.

The four aspects of product of P.W.B.S:1.System

Structural function or operational function of a producte.g::longitudinal bulkhead or transverse bulkhead, fire main system,mooring system, fuel oil service system, lighting system e.t.c

2.ZoneGeographical division of producte.g::cargo hold, engine room, superstructure

or their subdivision or combinatione.g::structural block or outfit unit

3.Problem area

Division of production process into similar types of work problems.e.g::a)by feature, curves vs. flat blocks

steel vs aluminium structure

b)by quantity, e.g:volume of blocksc)by quality, e.g:grade of workers ,grade of facilities requiredd)kind of work, e.g:marking, cutting, welding, blasting e.t.c

4.Stage


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A division of production process by sequence,e.g:substeps of fabrication, subassembly,erections e.t.c

Robotic weld

The utilization of industrial robots for weld processes, with specificemphasis on gas metal arc welding (GMAW) has been a practice forsome time .Industrial robots can positively impact the weldingprocess by providing the following major improvements to the manualprocess:1) Production increase2) Reduction of direct labor

3) Improvement of weld parameter and process control4) Removal of the operator from a sometimes tedious and potentiallyhazardous environment.

The important points to be considered for a welding robot are:1) It must be a point to point, continuous path robot.2) It must be able to record programs for back up.3) Operators must make sure encoders are set precisely.

4) The base must be mounted securely to the floor.5) It must have interface capabilities.6) Quality of robot weld.

The critical factors for the success of a robot arc welding systemcan be summarized as follows:1) Intelligent choice of family part selection.2) Concentration on refinement of manufacturing practices prior to

the arc welding requirement.3) Production and utilization of high integrity, machine tool qualityClass A fixtures.4) Detailed and documented evaluation of required weld parametersfor a specific process.5) Judicious use of part and material handling equipment.


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6) Proper system control for maximum operator efficiency.

TYPES OF WELDING ROBOTS:

Presently there are four types of welding robots .Their coordinationis:a) Rectilinearb) Articulatedc) Cylindricald) Spherical

In order to introduce a welding robot system successfully, overallconsiderations including structural design, assembly method, and costperformance were carried out:1) The effecting positioning facilities of the robot was designed tomove widely over the large hull structure using full NC system .Theportable type robot was adopted for the system.2) Full off line teaching system was developed, answering to thevariety of structure elements and welding patterns. The system now

has been applied in IHI shipyard successfully.

Market investigation

govt policy determines it like direct cost, rate of foreign exchange,Trade agreements between GOVT and countries

Type of ships

1.categorised to MULTIPURPOSE & SPECIALISED Ships2.range of DWTMax and min size of main dimensions4.trade route restrictions

Trade analysis


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1.Type of cargo2.vol of cargo3. Details of ship owners & companiestrend in requirements of new ships

STAGE IIPreliminary design investigation or skew design and costingdone to find the type of ship required to fit market requirementsFDG does this job and it fids the future aspects of ship building

STAGE III finalization of tenders and contractsHere fixation of prices occurs due to keen competition of manycompanies in tenders

tender is a document issued by the ship owner to convey the detailsof terma & conditions of the deals between the owner & ship yard

Management decides the Yard to which deal is to be given

Finalisation of the Technical specs of the ship

like1. quantum of cargo2.Type of cargo3.any other function to be performed other than carrying cargo or inaddition to carrying to cargoeg:carrying passengers, fishing tugs, naval ships, cable carrying ships,

dredgers

STAGE IV DETAIL DESIGNQuite a few items in this stage would have been completed beforesigning the contract. For a merchant ship dwt,type of cargo, function


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of ship,routes,engine power etc would have been finalised includingtowing tank test,maneuvring etc.

As fitted drawings:After the construction of the ship detaileddrawings of ships are made containing all information of the shipactually built.The various items of outfit could be decided evenbefore signing of a contract in case of a merchant ship.

STAGE IV PLANNINGa)Nature of the activity,its linkage with the activity before and afterb)Time schedule - time for each activity to happen

STAGE VI PRODUCTIONThe most important element in this stage is control which is done bythe production manager

STAGE VIICompletion of the ship, test,trials and delivery to the owner.

STAGE VIII GUARANTEEGenerally guarantee is one year of the ship.

SEQUENCE OF EVENTS1)Market analysis2)Preliminary design3)Finalisationand acceptance of tenders and documents4)Detail design

5)Planning6)Production7)Completion of ship8)Guarantee


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PRODUCTION SCHEDULE

Once the contract plans are released and basic planning is over,hullconstruction planning group initiates detailed planning in two phases:1)department level planning/scheduling2)shop level planning/schedulingScheduling can be defined simply as the allocation of resources and timefor various production units to closely match with the project completiondates and budget estimates.Basically it determines when and where,whatis to be done.There are four distinct stages to this:

I)Basic scheduling

Ship building master scheduling-relates all cardinal dates for allships/projects to be built in a specific period.

Hull erection master scheduling1)Responsibilty of the production engineer2)co-ordinates with onboard outfit schedules3)main input are block defintion plan4)emphasis on outfit of large macinery like diesel generator which have

to be fitted before any other block in ER.This requires treating such anitem as a seprater block.

Shipbuilding activity timing schedule1)using block predefinition plan,erection master schedule,outfitpalns,outfit master schedule2)bar chart showing the required time for each process right from yardplan issue to erection

3)provides dates for erection,commence and completion of hull assemblyissue of hull construction drawing,acquistion of materials,major outfit onboard dates4)it is the basis of all the schedules

II)Major scheduling


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Made from erection master schedule.It shows:a)shortest practical period of erectionb)easiest erection sequencec)duration required for fitting and aligning blocksd)date for erectione)daily m/h requirements for fitters and welders

IIa)Assembly master schedule1)derived from EMS,s/b activity timing,design maaster sschedule2)forecasted work is depicted using welding length for assembly3)duration required for assembly of each block for all ships

IIb)Integrated schedule1)i/p from o/f dpt,o/f shop master schedule2)shop schedules are updated every two months together with IIa

III)Working scheduling include:1)assembly,subassembly,part fabrication,monthly schedule2)yard plan,mold loft issue curves

Accuracy control

the use of statical principles to monitor,control and continously improveship building design details,planning and work methods to maximizeproductivity.It also provides a quantitative feed back loop b/wproduction,planning,design and engineering

Statical principles

1)nothing called absolute accuracy2)variations from specified dimensionds are always iminent3)fundamental basis is the theory of probability4)the dimensions vary from component to component due to inherentmachines characteristics,envt. conditions and workers expertise


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5)any important continous probablity distribution is a normal distributionor Guassian distribution6)it is the plot of the variation observed in the product.

Shell expansion:

it is a 2d drawing showing the arrangement of plates stiffner, buttseams and fillets. All vertical dimensions in this drawing are taken aroundthe girth of the vessel rather than being a direct vertical projection.This technique illustrates both the side plating and bottom plating as acontinuous whole. This also shows numbering of plates and lettering ofplate strake (R,A,B,....). For reference purpose, the strker run out as a

girth decreases fore and aft.Shell is expanded in the transverse plane. The girth of the maindeck, tween decks, double bottom, etc is taken at each station andordinate are plotted to get the profile and the shell expansion. Bulkheadsare fitted vertically and after that strakes are decided. The plate ineach strake is numbered from aft to forward. The girth of the shipdecreases towards the ends and so the width of the plate must bedecreased. To save making the plate too narrow at the ends, a number of

pairs of adjacent strakes are run into one. The strakes are taken frommidship drawing and the primary members are also plotted. The max sizeof the plate is 10X2.5 m and the other checks that are done are theminimum distance between the butt welds(150mm) minimum distancebetween any other two welds are100mm. Butt and seam at the position ofstiffening members should be avoided.

STANDARDISATION:

Standardisation means producing maximum variety of products fromminimum variety of materials, path, tools and process.Standardisation is one way wich leads to economicalproducts.Standardisation usually means that non standard products willnot be except when a customer orders them to be made.


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Standardisation is the process of establishing standards or units ofmeans by which extent of quality, quantity, value ,performance etc maybe compared and measured.ROLL OF STANDARDISATION IN SHIP DESIGN AND

CONSTRUCTION:1)Product standardisation2)Process standardisationStandardisation by series production:Design::Once a ship having produced for the sister ship, few specifications,drawings and parts list have to be prepared and issued.

:Thus more time is available to develop new designs or to improveestablished designs.:better resources utilisation is possible.:allocation of work to available talent. ie a naval architect can specialisein bow design ,propeller design or resistance calculation etc.

ACQUIRING STANDARDISATION IN DESIGN STAGE::With the help of feasibility study, decide what type of ships to be build

in future.:Define standard type of ships.(coastal tanker, VLCC, DH type etc):From thin type of ships, designer to develop minimum variety of ships tomatch the range.:Introduce new materials, components etc if necessary.:Define the main dimensions of the ship in a standard maner.ie It shouldbe compatable with existing ship.:Designing of lines, computer added designs to be used.ie fairing

softwares etc to minimise errors.

IN THE STRUCTURAL DESIGN STAGE[International Satndards]::Use plates and stiffeners which are of standard type.:Use standard type of joints.:Use materials of standard type.


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:Use of standardised equipment and outfit items.Eg::hatches, manholes,companion ways, doorsn windows, portholes, sanitaryfittings, plumbingand wiring fittings equipments like pumps etc.

ADVANTAGES OF SERIES PRODUCTION:a)Reduction cost:Design cost being spread over several ships.:Design over head spread over several ships.:Design due to ordering material and equipment is built.:Reduced rejuctions and scrap.ie Rework is reduced.

b)Increase in productivity:Experience gained while building first vessel can be used on thesubsequent identical vessel.

Other advantages:1)Scope for improved methods and layouts.2)Opportunities for more efficient design.3)Greatly reduces pre:production planning activities.

4)Well proven design and methods improve planing and control.5)Fewer delays arise from waiting for materials, instruction tools etc.6)Accurate delivery promises.7)Holding stocks of standard items.8)Storage and post location can be improved.9)Better inspection and quality control is possible.10)Quality standards can be easily defined.11)In the case of replacing of a ship, if standard items are used, it can

be easily replaced or repaired.

PROCESS STANDARDISATION:1)Manufacturing process:welding(welding manual):painting scheme


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:use of standard machines.Eg::CNC, plasma cutting.2)Process standards::Eg:: ISO 9000, 9001, EN 14000 etc.If process are good ,product is guaranteed to be good.3)Series ship production.

DISADVANTAGES OF STANDARDISATION:1)Reduction in choice of ships to be build.2)Changes in owners requirement(type of ship)seriously affect a shipyardproducing a standard type of ship.3)Difficult to introduce new models because of less flexible productionfacilities and due to high cost of specialised production equipment.

4)Favour for large famous shipyards.5)Standards are set to resist changes and thin standardisation maybecome a path to progress

STANNDARDISATION is divided into1)PRODUCTIt is divided intoi)ISI(industrial) ii)AGMARK(food) iii)STEP(software)

ISI is divided intoBS, BIS, DIN, JIS, NES, GOST

2)PROCESSi)ISO ii)ISM iii)EN 14000ISO is divide into 9000 and 9001

STANDARDISATION(as applied in ship building):

:A principle of design for production which aims at achieving repeatibilityin manufacturing process which leads to significant improvement inproductivity.:The main goal is to develop a group of standard building blocks that canbe combined to produce very different final products.There are basically 2 types of standards


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i)BASIC STANDARDS:It include material and component stand designstand, o/f stand, production engineering stand, andinspection stand.

Material and component stand:It covers hardware items such as steelplates, valves, pipe pieces, doors, ladders etc.O/f and design stand:use standard materials and components to form sbassemblies and O/f units.Production engineering stand:It describes the procedures and processesof production work.Inspection stand:It details procedures for accuracy control andinspection.

ii)STANDARD DRAWINGS:It show typical sub assemblies and o/f unitsthat can be used directly as new designs or guidance for preparing newdrawings.These include drawings for structures assembly, machineryarrangement, piping layout, o/f unit etc.

WORK INSTRUCTION DESIGN:

:groups design into by the product aspects, problem areas and stage orthe basis of manufacturing process.

:It consists of fitting work instruction for assemblyand ,manufacturingwork instructions for pipe pieces and other componenents.:regarded as an extension of transition design ito endproducts are yardplans or simply work instruction plans.:Material list of fittinng(MLF) and material list for manufacturing a pipepiece(MLP) or any component(MLC) is attached with each workinstruction design.WORK INSTRUCTION SCHEDULING:

:It includes preparation of weekly and daily schedules for Assembly, SA,PF using same patterns.:Weekly schedule order work to be performed over a 2 week period andupdate every week.:daily schedules regard work to be completed next day and are updateddaily by superiors.


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Ship Production II

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