nieland press bending

A REPORT

ON

THE BENDING PROCESS CARRIED OUT

USING SBP-275.

BY

SHASHANK 2007A1PS395P

AMEYA AMBARDEKAR 2007A3PS114G

ASEEM ROHATGI 2007A3PS171P

AT

CHOWGULE & CO. LTD. (SBD),

ZUARINAGAR.

A Practice School-1 station of

BIRLA INSTITUTE OF TECHNOLOGY &

SCIENCE, PILANI.

(JULY, 2009)

2

A REPORT

ON

THE BENDING PROCESS CARRIED OUT USING

SBP-275.

BY

SHASHANK 2007A1PS395P B.E Chemical

AMEYA 2007A3PS114G B.E EEE

ASEEM 2007A3PS171P B.E EEE

Prepared in partial fulfillment of the

Practice School-I Course

At

CHOWGULE & CO. LTD. (SBD),

ZUARINAGAR.

A Practice School-1 station of

BIRLA INSTITUTE OF TECHNOLOGY & SCIENCE,

PILANI.

(JULY, 2009)

3

Acknowledgements

We would like to thank Mr. Ashok Chowgule, Executive Director, Chowgule &

Co Ltd., for giving us the opportunity to work in and get exposure to a real

industrial environment. We would also like to thank Mr. Gajanan Porob,

Coordinator, Loutilim and Mr. Ravi Warad, in charge, Gadegally, for helping us

gain insight to the working of the organization.

We would like to thank Dr. Ramesha C.K, our PS-1 instructor, for his valuable

guidance throughout the program.

We would like to thank Mr. Vinayak, Senior Officer Design & Mr. Prashant

Narvekar, Officer at Piping section, for guiding us towards the various possible

projects available in the Unit and helping us gain the hands on experience and

knowledge required for working of the project. We would also like to thank

Mr. Sachin and all the other employees for their cooperation.

Finally, we would also like to thank Mr. Narayan (machine operator) who

explained us about the various bending procedures.

4

BIRLA INSTITUTE OF TECHNOLOGY &

SCIENCE, PILANI

Practice School Division

Station: CHOWGULE & CO. LTD. (S.B.D) Centre: Zuarinagar

Duration: 54 DAYS Date of Start: 25 /05 /09

Date of Submission: 14/07/09

Title of the Project:

A REPORT ON THE BENDING PROCESS USING SBP-275

SHASHANK 2007A1PS395P

AMEYA AMBARDEKAR 2007A3PS114G

ASEEM ROHATGI 2007A3PS171P

Name and Designation of the Experts:

MR. RAVI MANAGER (GADEGALLY)

MR. VINAYAK DESIGN OFFICER

MR. PRASHANT OFFICER –PIPING

MR. NARAYAN MACHINE OPERATOR

5

Name of the PS Faculty: Dr. RAMESHA C.K

Project Area: SHEET METAL BENDING

ABSTRACT

This report focuses on the cutting (plate marking) and bending section of the

Chowgule shipbuilding division. This report is intended for those who want to

learn how to bend the metal sheets using SBP-275 bending machine. It describes

the various steps of the bending process in detail.

The design department prepares the working drawings after receiving designs from

specialized Navel architect Firms. After the plan is created, a schedule is then

made using project management software, with the consultation of experienced

managers. After planning steel plates are taken for grit blasting, where they are

made rust resistant. The steel plates are then lofted for proper curves and shapes.

From there the steel plates are taken to the optical cutting machine for cutting in

desired shapes. After cutting the materials are taken to skids for assembly of

modules.

► The machine being used is NIELAND SHIP BUILDING PRESS SBP-

275.

► It is capable of doing both stretching and rolling

► The maximum thickness of plate which can be bent is 25mm.

► The maximum width of 2500mm plate can be stretched or rolled on the ship

building press.

6

Various steps in bending process are:-

Marking the plate.

Marking the Centre line (if required).

Marking the Bending Axis.

Bending using appropriate tool.

Checking the correctness of bend against the Standard Template.

Rolling if required is done before bending thereafter, punching followed by

stretching (if required).

Signature of PS Faculty Signature of the students

Date: -

7

TABLE OF CONTENTS

TITLE Page No:

Acknowledgements………….……………….…………………………………..3

Abstract Sheet……………………………………………………………….........4

Introduction………………………………………………………………….…...9

1. Cutting Section………….……………………………………………………14

1.1 Introduction to cnc machine….………………………………….……..14

1.2 Shape…….…………….……………………………………………....16

1.3 Plate work technique..………….....……………………………………17

1.4 Cutting………………………….……………………………………....20

1.5 Powder marking……………………………………………………......24

1.6 Hypertherm ht 4400………………………………………………..…..25

1.7 Optimizing marking…………………………………………………....28

1.8 Manual marking………………………………………………..............28

1.9 Automatic marking………………………………………………….....29

1.10 Procedure for running a program and plate cutting……..........................30

1.11 Beveling of plates……...……………………….……………..…………31

1.12 Procedure to be followed when electric supply goes off during the

cutting of plate by the CNC machine ……………………………….....32

1.13 Rules to be followed while cutting by CNC machine……….…………32

1.14 Dos and don’ts for Farley cnc machine…………………….…………...33

1.15 Precautions summary…………………..………………………….…….34

8

2. Bending and Stretching….…………………………….………….………...36

2.1 Stretching by pressing………………………………………………..….39

2.2 Stretching by rolling…………………………………………………......39

2.3 Concave bending………………………………………………………...40

2.4 Small concave bending……………………………………………….…40

2.5 Bending by pressing……...……………………………………………...41

2.6 Bending by rolling…...………………………………………………….42

2.7 Flanging………...……………………………………………………….44

3. The bending machine……………………………………………….............45

4. Working methods…….……………………………………………………..63

5. Bending Process…..………………………..……………………….............65

6. Rolling….………...…………………………………………………...……75

Conclusion..…………………………………………………………………….80

Appendix……..……………………………………………………………...…81

References………………………………………………………………...……82

Glossary...…………………………………………………………………....…83

9

INTRODUCTION

CHOWGULE GROUP

The group started in 1916, like any beginning, the group made it too in a small

way, with the export of tin scrap, coconut oil, wood and bamboo to the Middle

East, till they realized the tremendous potential of Goa in a field unexplored –

mining ore.

From modest beginnings in 1916, the CHOWGULE Group has today quietly

burgeoned into an industrial giant with activities in areas as diverse as:

1. IRON ORE MINING

Chowgule Mining Division in Goa is one of the modern and mechanized

mining complexes in India. With three sophisticated beneficiation plants, it

supplies the world with over 3.5 million tones of finest iron ore and iron ore

pellets each year.

2. TRANSPORTATION

Chowgule was the first to export iron ore to Japan and East Europe from Goa.

The company has hi-tech mining equipment and a modernized transportation

system which helps the export unit to meet the various contracts worth millions

of tones.

3. IRON ORE PELLETIZATION

Mandovi Pellets Iron Ore Pelletization Plant was set up in 1979 at Shiroda, Goa

with the annual capacity of 1.8 million tones. The fully mechanized plant with

the state- of- art technology was the first of its kind in India and largest in Asia.

10

4. INTERNATIONAL SHIPPING

Chowgule Steamships Limited (CSL) is part of the 1500 crore and 92 year old

Chowgule Group of companies from Goa, India. CSL is principally engaged in

the carriage of goods by sea, and is committed to serve its customers to their

satisfaction and mutual optimum benefits.

5. EDUCATION

Chowgule has got a number of colleges and schools and community centers for

the welfare of public, the most famous being the Smt. Parvatibai Chowgule

College of Arts & Science located in Goa itself.

6. INDUSTRIAL GASES AND INDUSTRIAL SALT

Established in 1965, the Company is a leading manufacturer of Industrial &

Medical Oxygen and Nitrogen with U.H.P Grade for last four decades.

Company’s ranges of gases include Nitrogen, Argon-Commercial & U.H.P,

Carbon dioxide, Acetylene, Nitrous Oxide I.P.

7. MARKETING AGENCIES

Chowgule has another extension named as Chowgule Industries Ltd that deals

with the industrial and consumer products such as KEL pearlite HASTI

sprinkles sets etc.

Also the group has taken the dealership of Maruti Suzuki and it has some five

centers all across the state of Goa. It has also got some investment schemes

beneficial for the public sector.

11

8. SHIPBUILDING

Shipbuilding is the construction of ships. It normally takes place in a

specialized facility known as a shipyard. Shipbuilders, also called shipwrights,

follow a specialized occupation that traces its roots to before recorded history.

Shipbuilding is an attractive industry for developing nations like India.

The shipbuilding division was established in 1951 in Goa ,it has right now three

divisions the main head office at loutulim ,subpart of which is in rassaim .All

the work of assembly of modules, their construction, survey and air pressure

testing, movement, launching and sea trial of the vessel are done in these two

year. The third yard in the Zuarinagar area known as Gadegally unit is

responsible for the designing, production, scheduling, grit blasting and painting

and CNC cutting.

Chowgule have a much automated shipbuilding facility at Gadegally. They have

two CNC machines imported from Australia for cutting purpose, one Sheet

Bending Press imported from Holland for bending the sheets. They use remote

controlled Goliath cranes. NC tube bending machine is being used for bending

of pipes.

They manufacture around five vessels a year and have a turnover of 300 crore.

Till date, the company has constructed over 100 vessels at the yard comprising

of Iron Ore Barges, Passenger Vessels, Deep Sea Refrigerated Fishing Trawlers,

Grab and Cutter Suction Dredgers, Tugs, Twin-hull Catamarans, Floating

Restaurants, etc.

12

The Chowgule & Company Shipyard also holds an International Ship Repair

License issued by the Directorate General of Shipping (Mumbai) and takes up

the repairs of sea-going vessels.

The various divisions at Chowgule Shipbuilding are:-

Blasting Section

Cutting Section

Piping Section

Blasting section is responsible for cleaning and painting of the steel sheets,

Cutting division does the cutting and bending of sheets using CNC machines,

Piping section is responsible for dispatching pipes and flanges of required

dimensions to LOUTOULIM and RASSAIM yards.

The steel plates are imported from Ukraine. The plates are classified according

to four grades based on their strength and toughness namely: GL-A, GL-D, GL-

E, and GL-AH36. Some plates are also bought from Indian manufacturer

ESSAR Ltd. The plates are then inspected and stacked on racks (as per

dimension and thickness), if no defects are found. Otherwise, the plates are sent

for rectification.

The design department prepares the working drawings after receiving designs

from specialized Navel architect Firms. After the plan is created, a schedule is

then made using project management software, with the consultation of

experienced managers. After planning steel plates are taken for grit blasting,

where they are made rust resistant. The steel plates are then lofted for proper

13

curves and shapes. From there the steel plates are taken to the optical cutting

machine for cutting in desired shapes. After cutting the materials are taken to

skids for assembly of modules.

Sheets are bent using Neiland Sheet Bending Press – 275 which has a maximum

capacity of 2750 kN. Rolling, Bending, Punching and Stretching are the various

operations which are being used for bending sheets.

In the pipe bending plant the pipes are sent through a sequence of processes

such as cutting, bending, fabrication(various parts such as elbows, clamps,

sockets, flanges etc. are butt joined together), welding, testing,

galvanizing/pickling and painting.

14

1. Cutting Section

1.1 Introduction to CNC machine

NC (Numerical Control) enables a machine to perform automatic actions. This is

achieved by coded instructions that were prepared on a computer system and

loaded into the machine in the form of a part program. The NC controller

commands NC machine motions. In order to carry out operations, the controller

requires information such as:

1) Work-piece dimensions

2) Tool selection

3) Tool travel

4) Cutting sequence

5) Width of cut (kerf)

6) Feed rates

This information is stored in a program in a format that is understood by the

controller. A large range of instruction codes provides flexible control and includes

necessary auxiliary functions to provide automatic gas switching, raising and

lowering of the tool and so on.

CNC (computer numerical control) plasma cutting has been around for 30 years,

but only in the past decade has it become affordable enough for the small shop.

The plasma cutting process, itself, is capable of almost surgical precision. It is the

15

human hand that guides a manual plasma cutting torch that is responsible for the

roughness sometimes seen in plasma cut pieces.

Today's CNC plasma cutting systems typically use the operator's personal

computer to create the shapes to be cut and control the cutting machine. The

resulting shapes are smoother than would be possible with a band saw, and can

include intricate curves, inside cuts, and sharp corners.

Fig. 1-1

Plasma cutters work by sending an electric arc through a gas that is passing

through a constricted opening. The gas can be shop air, oxygen etc. This elevates

the temperature of the gas to the point that it enters a 4th state of matter. We all are

familiar with the first three: i.e., solid, liquid, and gas. Scientists call this additional

state plasma. As the metal being cut is part of the circuit, the electrical conductivity

of the plasma causes the arc to transfer to the work.

The restricted opening (nozzle) the gas passes through causes it to squeeze by at a

high speed, like air passing through a venturi in a carburetor. This high speed gas

16

cuts through the molten metal. The gas is also directed around the perimeter of the

cutting area to shield the cut.

Fig. 1-2

1.2 SHAPE

Farley numerical controlled plate working (cutting, marking, drilling) machines

requires specific commands to control the tools. These commands are called NC

(Numerical Control) code. The two main groups of code are the internationally

standardized G code and the machine manufacturer’s proper M code.

To cut a part out of a plate, a series of these NC codes, called an NC program, is

loaded into the machine.

17

An NC program can be manually loaded into the machine using the operator panel,

or the ready to use NC program is loaded from a disk or a remote computer. An

NC program can be manually made or written from a hard copy drawing. If the

drawing is on a computer file, the NC program can be put together by a software

package. Shape6 is such a package. Shape6 utilizes CAD techniques to draw any

two dimensional part on the screen. The graphics minimize potential programming

errors by allowing the operator to examine the finished product on screen before

committing it to manufacture. After all the relevant data have been entered

(machine, tools, plate, nesting) Shape6 can then draw an NC program.

1.3 PLATE WORK TECHNIQUES

Efficient and safe plate cutting is based on knowledge and a process to gain and

update knowledge: communication. Whereas the production of an NC program is

very much a desk based activity, the execution of the program does require trade

qualifications. Having knowledge of materials like (non)ferrous/rare/bi metals,

aluminium and alloys helps taking care of everyday safety and cutting problems.

The following gives an overview of established plate cutting practices that help the

Shape6 operator to work effectively. However, to get the most out of the plate

cutting system, the operators of the Shape6 software and the cutting machine need

to communicate on a regular basis.

1.3.1 PLATE EDGE DETECTION

It must be possible to identify the edges of a rectangular shaped plate in an

automatic manner. The operator should only need to jog the torch onto the plate,

18

and hit the plate edge detection button. This should cause the machine to identify 4

pertinent points on the plate edge and identify a nominal size for the plate.

1.3.2 PLATE HEIGHT MEASUREMENT

Problems with part size often arise when doing bevel cutting due to a badly

levelled cutting table. It should be possible to “map” the plate on the cutting table

to measure the height deviation.

1.3.3 KERF (CUT LINE) WIDTH

Due to the width of the flame/arc, material is removed around the cut line. This is

the kerf and if we know this width, the dimensional error of the material removal

can be compensated. This compensation is phased in over the first segment of the

contour, refer to Figure 1-3. The machine operator sets the compensation value.

For plasma cutting it is recommended to cut the outside shape in a clockwise

(CW), the inside shape in an anticlockwise (CCW) direction.

Fig. 1-3

19

When kerf is specified in the above form, the amount of offset will not be at its

maximum at the start of the first cutting move. Instead, it ramps up from zero

offset to the maximum value over the length of the first move. Therefore, it is

important to include a leading cut from the first pierce.

1.3.4 LEADIN AND LEADOUT

To allow piercing of the plate in order to start the cut and stabilization of the

arc/flame a lead-in is applied at a safe distance from the part cut line. During the

lead-in/out also the kerf compensation and bevel angle are phased in/out, as the

piercing must be done at a bevel angle of zero degrees. The lead-in must have a

minimum length (10 mm for straight, 15 mm for bevel cutting); it should not be

combined with a cut line for a part. A bevel lead-in is best placed in line with a

corner, as shown in Figure 1-3.

1.3.5 SINGLE CUTTING

Cut one part at the time, as is to be expected with a single torch machine. A more

efficient program may be possible if the operator is briefed on the use of the part.

E.g. by moving the lead-in, a more effective nest coverage may be achieved; or test

cuts are made first to obtain the required accuracy of the cut part by cutting rather

than by grinding.

1.3.6 COMMON CUTTING

This refers to a cut being effective to two parts. Cutting a plate into strips is

efficient because all inside cuts result in a part on both sides of the cut; refer

examples in Figure 1-4.

20

Fig.1-4

1.4 CUTTING

Refer Figure 1-5. This is a form of common cutting where cutting time is reduced

by adapting the shape of the part in order to obtain continuous torch movement.

This works well if the required part dimensional accuracy is low

Fig.1-5

1.4.1 BRIDGE CUTTING

Bridge cutting applies to separate parts that are kept together with bridges, refer

Figure 1-6. The bridges may prevent small parts from falling down the worktable,

or improve parts handling after cutting. Bridge cutting results in a lower number of

pierces. The Platemaster software can only handle bridges of width zero. Such a

cut must be made with kerf compensation of the correct kerf width.

Fig.1-6

21

1.4.2 STITCH CUTTING

Stitch cutting, refer Figure 1-7, is mainly used when the whole plate must be kept

together for transport or further processing, e.g. - to roll a plate for a lobster back (a

function automatically performed by the Parashape software package).

Fig.1-7

1.4.3 SEPARATION EDGE CUTTING

The triple oxy cutting head is an arrangement of three torches which provides

cutting and PEP (Plate Edge Preparation) in one move, refer Figure 1-8. The PEP

may result in a straight, single or double bevel edge, the bevel angles being

manually adjustable before the cutting is started. The position of the torch set is

automatically kept perpendicular to the direction of movement of the torch set,

refer Figure 1-9. A cut should always be started from the edge of the plate.

Fig.1-8

22

Fig.1-9

1.4.5 THICK PLATE CUTTING

Plate with a thickness of more than 100 mm exhibits the following typical

problems:

1) The plate is too thick to be pierced and the cut must begin with an edge start.

2) The edge start for plate over 200 mm thick requires extra assistance by

grinding a V of 5 mm deep into the edge of the plate, refer Figure 1-10.

3) There is not enough heating capacity to preheat the entire plate, preheating is

only done following the cut path.

4) Because of local (pre)heat only, the plate has high temperature differences,

resulting in plate buckle. To reduce buckle the use of locks is recommended,

refer Figure 1-10.

Fig.1-10

23

1.4.6 BEVEL CUTTING

Bevel cutting results in an angled plate edge, obtained by keeping the cutting torch

arc tan angle other than perpendicular to the plate surface, refer Figure 1-11.

Fig.1-11

A bevel is called negative/positive if the surface area of the top of the plate (when

on the cutting machine) is smaller/larger than the bottom area. Shape6 requires

beveled areas to be identified by the largest area that is the outer of the two

contours of a bevel cut. A bevel cut line is shown on the screen by a dotted line.

Compensation of effects due to bevel angle and kerf width, refer Figure 3-10, is

taken care of by the CNC.

Fig.1-12

24

1.5 POWDER MARKING:-

Fig. 1-13

Set up your flame as shown in Figure above. Ensure that the mixing oxygen and

marking are closed.

Slightly open the mixing and marking oxygen. Place the CUT/MARK button to

ON and you should get a flame as Figure 1-14. For adjusting the flame, the rule of

thumb is that mixing oxygen will determine the force in which the powder is

flowing. Therefore, if you have a wide powder flame which is not straight, the

Poor marking Ideal condition No marking

No colourOrange-red

Excessiveblow oxygen

Balanced markingoxygen & powder

feed oxygen

Insufficientcarrier oxygen

Long extendingwhite flame withfading tip on topof primary flame

White flame shinesbrightly and theform is sharp

Pastel colouredflame and the form is sharp

Excessivegas flame

Standardflame

Excessiveoxy flame

25

mixing oxygen is the one to adjust.

Once you have the correct flame, drive the torch over the plate. Bring the torch

down so it is approximately 75 mm above the plate. Put the CUT/MARK button

ON and drive the machine across the plate at approximately 5000 mm/min. Do this

manually or write a program. Once the torch is moving, it is a matter of adjusting

the marking and mixing oxygen until a nice line appears. You should be able to get

a line 1 mm wide. Remember that the mixing oxygen determines the volume of

powder and therefore the width of the line. The marking oxygen determines the

force of the powder and the amount of powder on the plate. The speed will also

affect the width and the amount of the powder applied.

You may find that it will take some time before you get the desired results. You

can mark at a speed of up to 10,000 mm/min but it is suggested that you start at

around 5000 mm/min.

1.6 HYPERTHERM HT4400

SYSTEM SPECIFICATIONS

• 50 Amp, 100 Amp, 200 Amp

• HySpeed Dual Gas Dry Plasma

• Long Life Oxygen Plasma Cutting

• Carbon, stainless, and aluminum

• 100% Duty Cycle Throughout Entire Cutting Range

26

TThhee LLoonngg LLiiffee PPrroocceessss

Hypertherm improves electrode life by controlling the ramp up/down of

current and gas flow. The Long Life Process reduces the amount of

hafnium lost during each arc start and stop.

27

RESTARTING PROCEDURE

If the pressure setting and the valve adjustments have not been disturbed, then

proceed as follows:

1) Ensure that the machine is in manual mode.

2) Select marker by pressing the select marker push button.

3) Turn on preheat - select low preheat.

4) Turn on the marking oxy - select cut/mark.

BBaassiicc SSyysstteemm LLaayyoouutt

Power Supply

CNC

Torch

Work Table

O2 N2

Gas Hose Assembly Water (coolant) Control Cable Electrode (-) Lead Work (+) Lead Torch Leads

Off Valve

Air

Gas Console Water Cooler

Ignition Console

28

1.7 OPTIMISING MARKING

Due to the variable conditions of powder, nozzle, flame settings etc., it may be

necessary to make adjustments to obtain the optimum performance. Several factors

may affect the line quality:

1) Nozzle height,

2) Marking oxygen pressure,

3) Powder depth in chamber, and/or

4) Valve adjustment at powder feed oxygen and marking oxygen (see the two

figures above).

The most common cause of marker failure is blockage of the nozzle due to a

buildup of moist powder on the end of the tip, particularly if used with a water

table system. This can be verified by firstly switching off the flame then turning on

the marking oxy jet. If the oxygen flow is non-existent or very low then a blockage

is most likely. Remember also that no powder flow may mean an empty powder

chamber.

A blockage is easily removed by careful use of a conventional tip cleaner,

Although care should be taken to ensure adequate eye protection since there may

be a release of residual pressure from the marker when the blockage is cleared.

1.8 MANUAL MARKING

1) Set up the marking blowpipe as described above;

a) Select manual mode, and

b) Select marking mode, choose the select marker option.

2) Set the nozzle to plate height to between 25 - 75 mm.

29

The height can be set either:

a) Manually by jogging the relevant torch with its height up/down

buttons, or

b) Automatically, via the height sensing system which is activated by the

auto height button.

1) Set a suitable marking speed.

2) With the marker(s) switched on, use the jog buttons to move the marker so as to

mark out the plate.

1.9 AUTOMATIC MARKING

The powder marker is usually mounted adjacent to the oxy fuel torch. Because of

this physical separation it is necessary for the CNC to offset the machine when

going e.g. from cutting to marking.

This is accomplished via tool offsets, which must be entered at the keyboard by the

operator. The proper tool offset code for marking is T0202. The T02` part refers to

marking mode, and the 02 suffix refers to the appropriate physical offset between

the marker and the reference tool (laser). Thus the CNC is able to compensate for

physical offsets between tools when running a program.

The marker on and off functions are performed by the M codes M77 and M79

respectively whilst in auto mode.

Before running an NC program using the marking option, the marker settings

should be checked in manual mode as described in the previous section. The

plasma, oxy, marking, preheats on/off and oxygen on/off switches are disabled

when the machine is in auto mode, and are usually left set as follows:

30

Plasma-oxy marking: any mode

Preheat on/off: off

Oxygen on/off: off

1) Select the required program.

2) Set the appropriate torch boxes to on or auto as required. If auto height

control is required, select the auto height.

3) Press cycle start to execute the program.

1.10 PROCEDURE FOR RUNNING A PROGRAM AND PLATE

CUTTING:-

1. Load the plate is on the water table in the cutting zone.

2. First home the machine.

3. Travel the machine in the y- axis by pressing the strip button and right arrow

button.

4. Then remove by pressing the strip button the machine will stop.

5. Select the manual mode.

6. Switch the laser on.

7. Tool will be zero (laser on).

8. Position the laser at the desired point.

9. Turn off the laser spot device by pressing laser spot.

10. Press the set zero to set the work piece zero.

11. Travel the machine along the y- axis (along the rail) corner vertically and

where the x-axis is zero and set the plate angle.

12. Set the bevel table off if no bevel is to be cut.

13. Go to set avc and set avc according to the consumables used and the

thickness of the plate.(as per the manual )

31

14. Set the pierce delay time.

15. Set the initial pierce height.

16. Set the ihs as per the his chart and set the same avc for all sides /angles.(for

straight yes and bevel no )

17. Check the plasma setting torch 1 and timers and set if necessary according to

the consumables used.

18. Go to the set active remote active and select the program to be cut and press

enter.

19. Then the machine will check the program for errors and if ok will give green

strip in the control panel (yellow strip errors which are not necessary

important and red strips some errors which should be rectified.)(Design to be

informed and rectification to be carried out.)

20. Press auto button then cycle start it will flicker, and the program is on and it

will start printing and cutting.

21. Raise the water level of the water table as per table 1 and table 2 and once

the level is attained put off the knob on the control panel.

22. The plate will be cut accordingly.

1.11 PROCEDURE FOR BEVELLING OF PLATES:-

1. Go to set up more press f9 function key.

2. Select the bevel offset by pressing f2 function key.

3. Then select the suitable bevel table for the plates, example m.s- 200 and

enter of single bevel and m.s-200db for double bevel and triple bevel as per

the chart and plate thickness.

4. Select the table by pressing the f5 function key as per the plate thickness.

5. And the press f8 function key to choose the plate thickness.

32

6. Then go to show data by pressing the f2 function key and set the AVC by

pressing the f 7 function key.

7. Select the one avc sp for all angles select n for no and enter

8. Then the bevel angle selected will be cut accordingly by the machine.

1.12 PROCEDURETO BE FOLLOWED WHEN ELECTRIC SUPPLY

GOES OFF DURING THE CUTTING OF PLATE BY THE CNC

MACHINE

1. Temporary home the machine by pressing home button.

2. If the supply is cut off for more than 20 minutes redo the plate /angle setting.

3. Press the mdi to 00.

4. Run the machine program.

5. Laser will go to the actual position and reset the settings.

6. If the supply is received in less than 20 minutes go to plate zero by pressing

plate zero.

7. Run the program with dry running up to the last point where the tool was

cutting or printing when the supply was out.

8. Stop the dry running.

9. Then the program will automatically start cutting the plate.

1.13 RULES TO BE FOLLOWED WHILE CUTTING WITH FARLEY

CNC CUTTING MACHINE:-

1. Cutting at inner side should be always ANTICLOCKWISE DIRECTION

and outer side should be always CLOCKWISE DIRECTION.

2. Kerf compensation must be G41 code ALWAYS.

33

3. If you have G41 H1, in the program. It means that the machine will accept

the kerf number 1 table.

4. Give Lead in / out at least 15mm (Piercing).

5. Plate margin at outer periphery of the plate keep at least 15mm on the both

the sides.

6. Add BRIDGES between flat bars, small components and balance piece

alongside a big component and make the bridges to be cut afterwards.

7. AVC and speed to be selected from the table attached.

8. Electrode to use: - 6& 7mm – 200Amps

7.5-10mm – 300Amps

10.5& above –400Amps

9. Setting higher speed on machine will not take any effect. The machine speed

always depends on the Program speed only.

10. Plate Angle to be set on Y-axis (along the length of the bed) and not on X-

axis

3.14 DOS AND DONT’S FOR FARLEY CNC MACHINE

1. Check the AIR PRESSURE in the compressor. Normally it should be

10kg/cm2.

2. Check the Rail whether it is free from dust and obstacles.

3. Check Cooling fans are working properly.

4. Clean torch threads and current ring.

5. Check the Consumables before start cutting.

6. Check the Gas flow settings. (MV 1-7, CUT PRESSURE, CUT FLOW)

34

7. Check the Machine Parameters AVC, KERF, and IHS, as per the plate

thickness.

8. Check the Coolant level in Plasma

9. Check the Plate angle (Always in Y axis)

10. Check the Water level in the water table.

11. No Arc Welding has to be done while the Plasma in on.

12. Check the Ink and solvent level.

13. Home the machine at the Lower Left corner of the Table 1. Don’t Home the

Machine anywhere.

14. Cut the Trial Piece while change of each consumables and every shift.

15. After the shift is over do Flushing by solvent.

3.15 PRECAUTIONS SUMMARY

The dangers from toxic gases will vary dramatically from installation to

installation with such factors as:

1) Water spray/water muffler use around plasma torch,

2) Air movement and confinement,

3) Use of fume extraction table,

4) Operator proximity,

5) Cutting time vs. idle time,

6) Number of cutting torches, and/or

7) Atmospheric conditions.

Personal particulate respirators, welding helmets, earmuffs, protective dark

clothing and gloves etc. can reduce the damaging effects of all arc welding and

cutting equipment.

35

Although most of the gases given off by plasma arc cutting disperse quickly,

plenty of ventilation and air movement past the operator is recommended.

Fume extraction worktables, carriage fume extraction, and water tank type

tables, particularly when used in conjunction with plasma torch water-shrouds

can minimize the hazards.

36

2. BENDING AND STRETCHING

The shipbuilding press is constructed as a portal press and consists of four main

parts, a left and right column and an upper and lower bridge. These four parts can

be bolted together into one. The upper bridge contains the main cylinder with the

mounted tools.

The lower bridge contains the pressing or rolling table on which the tools are

mounted.

The picture shows the holder on which the tool is mounted

Fig. 2-1

The deformation of steel plates consists principally of stretching and / or bending

the material, in other words loading over the yield point, through which a

permanent deformation will be caused.

37

The picture shows the table on which die is mounted.

Fig. 2-2

Various tools available for bending are:

Bending

Punching

Stretching

Rolling

Flanging

The pressing tools available are for following processes:

1. Stretching

2. Bending (in one direction)

3. Concaving (in two directions)

4. Small concaving

5. Flanging (square bending)

38

Rolling tools are available for:

► Stretching (with the flat upper and lower roll)

► Bending (with the convex upper and concave lower roll)

With the help of a sophisticated control system it is possible to achieve very

accurate pressure and depth adjustments during the process. It is possible to control

the pressure with a precision of 1 metric ton and depth with a precision of

0.1mm.The two cranes are used for the transport of plates from the cnc cutting

machine to the bending machine.

The production of steel plates for ships mainly consists of stretching, bending and

flanging, the following tools are used:

Pressing tools for stretching

Rolling tools for stretching

Pressing tools for concave bending

Rolling tools for concave bending

Small concave bending tools

Bending tools

Flanging tools for square bending

For the transport of the plates through the machine two semi portal cranes are

supplied. The cranes transport the plates over a specified distance. The cranes are

controlled from the movable control desk.

39

2.1 STRETCHING BY PRESSING:

The stretching of the material consists of loading the material over the yield point,

this causes a permanent deformation. The required stretch depends on the shape of

the plates in use. Most plates will be stretched with circa 0.1% up to 0.5%. In

special cases will be stretched up to max 5%. For the stretching of plates the

combination of stretching stamp and die is used. It is possible to stretch position

dependent or pressure dependent. Mainly the pressure dependent method is in use.

Fig. 2-3

2.2 STRETCHING BY ROLLING

The rolling tools can be used for stretching. In this case the flat upper and lower

rolls have to be used. Strong stretching can be obtained by using the convex upper

roll in combination with a flat lower roll. Rolling can take place pressure

40

dependent or position dependent. In most cases the pressure dependent method id

used.

2.3 CONCAVE BENDING

The concave bending tools are used for the bending of plates in two directions. The

tools consist of a convex stamp and a concave die. In most cases the pressure

dependent method is used.

Fig. 2-4 Fig. 2-5

2.4 SMALL CONCAVE BENDING

The small concave bending tools is used for the bending of plates in two directions

with a small radius. The tools consist of a small convex stamp and a press ring. In

most cases the pressure dependent method is used.

41

Fig. 2-6

2.5 BENDING BY PRESSING

The bending tools are used for bending in one direction. The tools consist of four

bending stamps and two dies. Dies can be mounted in different positions on press

bed. We have to take care that the dies are symmetrically mounted to avoid

damage to cylinder and tools. The four bending stamps can be mounted on the top

holder, it is possible to use different number of stamps for different plates. Position

dependent pressing is applied.

42

Pressing Table

Fig. 2-7

2.6 BENDING BY ROLLING

It can be in one direction or two directions. Bending in one direction is obtained by

rolling over the whole length of plate with constant or changing pressure/position

using convex upper and concave lower. Bending in two directions is done using

rolling locally with changing pressure/position.

43

Fig. 2-8

44

1.7 FLANGING

The flanging tools are used for square bending of plates. The tools consist of five

flanging stamps and one flanging die. In most cases the flanging takes place in

manual control using a specific pressure for a specific time.

45

3. THE BENDING MACHINE

The shipbuilding press, constructed as a combi-press, is intended to deform plates

by pressing or rolling. The machine can process all types of plates occurring in the

shipbuilding industry such as hull plates, knee stiffeners, bends, partition walls,

covers and doors. The machine is built in such a way that it is possible to stretch or

deform plates with a maximum thickness of approximately 25 mm. Of course this

depends upon the material that will be processed. The machine is suitable for

processing plates with a maximum width of 2500 mm. In this case both ends of the

plate can be processed. The machine is designed to operate only with tools that are

manufactured by VanderPloeg B.V.

There are three operation locations. A Motor Control Centre (10) on the right side

of the machine for starting up the machine, a Movable Control Desk (11) with a

control panel (HMI) for controlling the entire machine including the cranes and a

Remote Control for the most elementary controls of the machine.

The shipbuilding press consists principally of the following parts (refer figure on

next page):

Part

no.

Name

1 Lower bridge

2 Upper bridge

3 Left column

4 Right column

5 Cylinder

46

6 Pressing table

7 Press bed

8 Rotatable table support

9 Hydraulic compartment with pumps and

control unit

10 MCC

11 Movable control desk

12 Swivelling arm

13 Identification plate

14 Pressure gauge reading

15 Oil cooler

16 Lighting

17 Gantry crane

18 Hoist

47

Movable Control Desk (MCD)

NO. NAME TYPE FUNCTION/OPTIONS

24S4 Pressing/rolling Selector

switch

Pressing = enables pressing.

Rolling = enables rolling.

25S1 Pressure/

position

dependent

Selector

switch

Pressure = enables pressure dependent

pressing/rolling.

Position = enables position dependent

pressing/rolling.

24S1 Man/single/auto Selector

switch

Man = enables manual control.

Single = enables single stroke operation.

Auto = enables automatic operation.

24S2 Auto cranes Selector

switch

Rev = Crane drive backwards (automatic

mode).

0 = Automatic crane drive turned off.

For = Crane drive forwards (automatic

mode).

26S5 Auto trolleys Selector

switch

Left = Trolley drive leftwards (automatic

mode).

0 = Trolley drive turned off.

Right = Trolley drive rightwards (automatic

mode).

24S3 Crane choice Selector

switch

0 = Cranes turned off in automatic mode.

1 = Crane one in operation in automatic

mode.

1+2 = Crane one and two in operation in

48

automatic mode.

2 = Crane two in operation in automatic

mode.

26S6 Twisting Selector

switch

To turn twisting on/off. When on the

trolleys of crane 2 move in opposite

direction of crane 1 (automatic mode).

25S6 Control off/on Key switch Turn key to switch control voltage on/off.

42H0 Standby Indicator

lamp

Burns when main and auxiliary motor are

on, and blinks when they are starting up.

42H1 Control voltage Indicator

lamp

Burns when control voltage is present.

HMI Operator panel Text panel Human Machine Interface = Inputting

device (see chapter 7).

23S6 Start Illuminated

push button

When lamp (42H3) blinks it invites you to

push this button to start the main and

auxiliary motor. Pushing this button when

motors are on will start automatic or single

stroke operation.

23S7 Stop Push button Push to stop automatic operation.

26S1 Hoist 1-1 Illuminated

push button

Push to turn Hoist 1-1 on/off.

Lamp (42H4) burns when Hoist 1-1 is

turned on.


push button



turned on.

26S3 Hoist 1-2 Illuminated Push to turn Hoist 1-2 on/off.

49

push button Lamp (42H6) burns when Hoist 1-2 is

turned on.


push button



turned on.

27S1 Hoist 1-1 Control lever 1 click up/down = hoist 1-1 slow speed

hoisting.

2 clicks up/down = hoist 1-1 high speed

hoisting.


hoisting.


hoisting.


hoisting.


hoisting.


hoisting.


hoisting.

50

Remote control (RC)


23S1A Push-button Move cylinder upward

23S2/

3A

Push on

button

Push 1 click: move cylinder downwards slow

Push 2 clicks: move cylinder downward fast

23S4A Push-button Push to drive/roll forwards

23S5A Push-button Push to drive/roll reverse

23S6A l Push-button Push to start automatic or single stroke

operation

23S7A Push-button Push to stop automatic operation

51

24S1A Manual Push-button Keep pushed to enable manual control

temporarily

13S3 Emergency

stop

Push-button Push to stop the complete installation

(emergencies only)

Altered functions when:

Pressing is enabled (24S4)

Position dependent method is enabled (25S1)


Remote control (RC)

52

23S1A Push-button Decrease stop-position with 0.1 mm

23S2/

3A

Push on

button

Increase stop-position with 0.1 mm

When both buttons are pressed simultaneously the stop-position will be stored


Pressing is enabled (24S4)

Pressure dependent method is enabled (25S1)


23S1A Push-button Decrease stop-pressure with 1 Metric Ton

23S2/

3A

Push on

button

Increase stop-pressure with 1 Metric Ton


Rolling is enabled (24S4)

Position dependent method is enabled (25S1)


23S1A Push-button Decrease stop-position with 0.1 mm

23S2/

3A

Push on

button

Increase stop-position with 0.1 mm

53

When both buttons are pressed simultaneously the stop-position will be stored

(teach in)


Rolling is enabled (24S4)

Pressure dependent method is enabled (25S1)


23S1A Push-button Decrease stop-pressure with 1 Metric Ton

23S2/

3A

Push on

button

Increase stop-pressure with 1 Metric Ton


Single stroke or automatic operation is enabled (24S1)


23S7A Push-button Push for a ½ second to move cylinder up

54

THE OPERATOR PANEL:-

Introduction

The front view of the operator panel OP7.

OP7

1. LCD display (contrast can be adjusted by "SHIFT" + "+/-").

2. Function keys F1-K4.

3. Alarm LED.

4. Help LED.

5. Shift LED.

6. Move one character, field, entry or display to the left.

7. Move one character, field, entry or display up.

55

8. Move one character, field, entry or display to the right.

9. Move one character, field, entry or display down.

10. Escape key to cancel an input job, cancel the display of help text or hide a

non-serious system message.

11. Acknowledge alarm messages. The alarm LED (3) is on when there is an

alarm message present and flashes when only acknowledged alarm messages

are still queued.

12. Numeric keypad.

13. Enter and terminate your input.

14. If the help LED (4) linked with this key comes on, you can open a context-

sensitive help text specifically about the screen currently displayed.

15. When entering values in a field with string format, a space (blank) is

inserted or a character is deleted at the current position of the cursor

dependent on the shift function (16).

16. Shift key for enabling the second function of dual-assignment keys. Push

once to toggle between enabled or disabled. The state of the shift key is

indicated by the shift LED (5).

When the electric system is turned on, the following text will appear on the

display:

By pressing the "▼"-key the following will appear:

TOTAL HOURS IN

OPERATION:

OIL TEMP. : DG.C

The start-up text when the electric system is turned on.

Hour counter.

Oil temperature in °C.

56

When the main motors are started, the main menu will appear. The menu that will

appear depends upon the positions of the selector switches. There are five possible

menus:

Tools;

Pressing (Position dependent);

Pressing (Pressure dependent);

Rolling (Position dependent);

Rolling (Pressure dependent).

Table/Tools rotation (OPTIONAL)

When the table/tools are unlocked (selector switch "TOOLS

UNLOCKED/LOCKED" is switched to "UNLOCKED") the following text will

appear on the display:

TABLE/TOOLS

ACT. ANGLE : DGR

DGSPEED : %

ROTATION

Current angle of the table support.

Rotation speed (0-100%).

To rotate the table just fill in a rotation speed and control the rotating direction by

turning the selector switch "TOOLS" to the left (anti clockwise rotation) or to the

right (clockwise rotation). The selector switch “MAN/SINGLE/AUTO” has to be

on “MAN”.

When the support table is at its zero point (0 degrees) the positioning pin should

point into the direction of the left column and align the centreline of the roll or the

short side of the press bed with the centreline of the press. If somehow the zero

57

point is incorrect you can correct it by reposition the support table and then reset

the current angle by pushing function key F4. To avoid resetting accidentally, this

function is protected by a password (password = 100). After entering the correct

password, you have to push function key F4 again to reset the value of the current

angle to 0 degrees.

Also automatic rotation is possible. Turn the switch “MAN/SINGLE/AUTO” on

“AUTO”.

The next display will appear on the display:

TABLE/TOOLS

ACT. ANGLE:

ADJ. ANGLE :

ROTATION

Current angle of the table support.

Adjustable angle (0-359 degree) of the table support.

After adjusting the desired angle, keep turned the selector switch tools to the left or

to the right. The table will rotate automatically to the adjusted angle.

Pressing (position dependent)

To enable position dependent pressing, the selector switch

"POSITION/PRESSURE" has to be switched to "POSITION" and the

"PRESSING/ROLLING"-switch to "PRESSING". The following text will appear

on the display:

PRESSING

CURRENT :

Current position of the ram in respect to the upper

58

STOP :

STROKE :

position (read only).

Stopping position (20.0-480.0 mm) in respect to the

upper position.

Stroke (0.0-400.0 mm) in respect to the stopping

position.

By pressing the button "" or "" on the remote control or the push buttons

“INCREASE”, “DECREASE” on the MCD during single stroke or automatic

operation, the “STOP” position can be in- or decreased in steps of 0.1 mm. When

both buttons are pressed simultaneously, the current position will be stored (teach

in). By pushing the "▼"-key several times the following text will appear:

BRAKE :

HOLD DOWN :

Braking distance (0.0-100.0 mm) in respect to the

stopping position.

Hold down time (0.00-10.00 sec).

By pushing the "▼"-key again several times the next window will appear:

TR. CRANE :

TR. TROLLEY :

CRANE L. SP :

CRANE H. SP :

Travelling time (0.00-10.00 sec) of the crane(s).

Travelling time (0.00-10.00 sec) of the trolley(s).

Crane low speed (0-100 %) = auto travelling speed.

Crane high speed (0-100 %), only in manual control

available.

Changing the values on the operator panel:

Select the field to be changed with "▼"- or "▲"-key

59

Type with the numeric keys the desired value

Accept the setting with the enter key

Pressing (pressure dependent)

To enable pressure dependent pressing, the switch "POSITION/PRESSURE" has

to be switched to "PRESSURE" and the "PRESSING/ROLLING"-switch to

"PRESSING". The following text will appear on the display:

PRESSING

CURRENT (TON) :

STOP (TON) :

STROKE (MM) :

Current pressure in metric tons.

Stopping pressure (0-275TON).

Stroke (0.0-400.0 mm) in respect to the stopping

position.

By pressing the button "" or "" on the remote control or the push buttons

“INCREASE”, “DECREASE” on the MCD during single stroke or automatic

operation, the “STOP”-pressure can be in- or decreased in steps of 0.1 Metric Ton.

By pushing the "▼"-key several times the following text will appear:

BRAKE (MM) :

HOLD DOWN (SEC) :

Braking distance (0.0-100.0 mm) in respect to the

stopping position.

Hold down time (0.00-10.00 sec).

By pushing the "▼"-key again several times the next window will appear:

60

TR. CRANE (SEC) :

TR. TROLLEY (SEC) :

CRANE L. SP (%) :

CRANE H. SP (%) :

Travelling time (0.00-10.00 sec) of the crane(s).

Travelling time (0.00-10.00 sec) of the trolley(s).



available.





Rolling (position dependent)

To enable position dependent rolling, the switch “POSITION/PRESSURE” has to

be switched to “POSITION” and the “PRESSING/ROLLING”-switch to

“ROLLING”. The following text will appear on the display:

ROLLING

CURRENT (MM) :

STOP (MM) :

ROL SPEED (%) :

Current position of the ram in respect to the upper

position.

Stopping position (20.0-480.0 mm) in respect to the

upper position.

Rolling speed (0-100 %).

By pressing the button "" or "" on the remote control (after pushing the

"START"-button) or push buttons “INCREASE”, “DECREASE” on the MCD, the

61

“STOP”-position can be in- or decreased in steps of 0.1 mm. By pushing the "▼"-

key several times the following text will appear:

CRANE L. SP (%) :

CRANE H. SP (%) :



available.

Because of the fact that the maximum crane speed is higher than the maximum

rolling speed, you have to find a setting that makes the rolling speed equal to the

crane speed (for example: ROL SPEED : 80% CRANE L. SP : 60%) before you

actually start rolling.





Rolling (pressure dependent)

To enable pressure dependent rolling, the switch "POSITION/PRESSURE" has to

be switched to "PRESSURE" and the "PRESSING/ROLLING"-switch to

"ROLLING". The following text will appear on the display:

ROLLING

CURRENT (TON) :

STOP (TON) :

The current pressure.

The stopping pressure.

62

ROL SPEED (%) : Rolling speed (0-100 %).

By pressing the button "" or "" on the remote control (after pushing the

"START"-button) or push buttons “INCREASE, “DECREASE” on the MCD, the

“STOP”-pressure can be in- or decreased in steps of 0.1 metric ton. By pushing

the "▼"-key several times the following text will appear:

CRANE L. SP (%) :

CRANE H. SP (%) :



available.

Because of the fact that the maximum crane speed is higher than the maximum

rolling speed, you have to find a setting that makes the rolling speed equal to the

crane speed (for example: ROL SPEED : 80% CRANE L. SP : 60%) before you

actually start rolling.





63

4. WORKING METHODS

There are a number of possible working methods:

Pressing can be divided into single stroke/automatic operation and manual control,

single stroke/automatic operation can be divided into position and pressure

dependent. Rolling always takes place in automatic control and can be divided into

position and pressure dependent (fig.6.1)

POSITION DEPENDENT PRESSURE DEPENDENT

SINGLE STROKE/

AUTOMATIC OPERATION

MANUAL CONTROL

PRESSING

POSITION DEPENDENT PRESSURE DEPENDENT

AUTOMATIC CONTROL

ROLLING

WORKING METHODS

Manual control pressing

When manual control is enabled it is possible to control every function manually.

The amount of pressure applied is controlled manually, if you keep the stick

pressed for long it will result in larger pressure being applied.

64

Single stroke and automatic pressing

In single stroke pressing the stamp applies the set pressure only once.

In automatic pressing the movement of the stamp is automatic and applies the same

pressure in each of the strokes automatically. Time interval between two strokes

can be controlled.

Position dependent

The amount of pressure can be controlled by specifying the length of each stroke.

The stamp goes up till that position applying the required pressure.

Pressure dependent

The amount of pressure applied can also be directly controlled by directly

specifying the pressure in tons. The maximum pressure that the machine can apply

is fixed which is 275 ton in this case.

65

5. BENDING PROCESS:-

1. Firstly, the plates are cut and marked using the CNC machines. Markings are

done on the plate to help the bending operator in positioning the different

templates and template numbers are also specified next to the marking to tell

exactly which templates are to be placed where.

Fig. 5-1

Plate before bending.

66

Sides are marked as UP and DN (down) as shown in figure.

2. Templates

This is the most important tool for the bending operation. Template tells the

operator which plates are to be bent where and to which extent. It is not

possible to carry out the bending operation without the corresponding

template. Templates are placed over the markings to check for the

correctness of bending.

Template number is marked on the template and also the arrow

marked tells how to place the template (arrow points to the DN side).

Fig. 5-2

3. Bending axis

It is marked so as to tell the operator where to bend and the angle at which it

is to be bent. In this process the two templates are placed on the markings

67

done by CNC thereafter, the operator holds the template to check whether

the top edge of the two templates is aligned and marks the point where the

two templates touch the metal plate. A line is then drawn joining the two

points. This line is known as the Bending axis.

In certain cases where the plate size is more than the template size, centre

line needs to be marked for exact positioning of the templates. It is marked

by finding the centre of the edge at both the ends and then drawing the line

joining them.

Image shows that the edges of both the templates are aligned.

Fig. 5-3

68

The white line shown is the bending axis.

Fig. 5-4

4. The plates are then bent along the bending axis using the appropriate tool.

First of all rolling is done (if required) followed by bending. Also some

plates are punched followed by stretching to release the stress developed in

the plate. The plates are lifted with the help of cranes to open the face where

bending is required usually a gap of 50 mm or so is kept between the plate

and die. The plate on applying pressure stretches, so it needs to be closed

from the ends so as to control the bending direction. It is possible to give a

bending angle of up to 900 using flanging tool.

69

The image on the following page shows that the plate needs to be bent from

the sides.

Fig. 5-5

5. This picture shows how the region in which bending is to be done is

determined. As shown in the figure the point where the template pivots is

marked. This operation is performed on both sides of the plate. This

determines the boundary of the bending region.

70

Image below shows where the pressure is to be applied exactly (white circle) it

is determined with the help of template, wherever the plate touches the

template at one point it is marked.

Fig. 5-6

6. This photo shows the entire bending region marked on the plate.

Fig. 5-7

71

7. After the entire bending region is covered, the bend is checked against the

standard templates. In this picture the bend has become more concave then

needed. The region where the template does not exactly fit the plate is

marked.

Fig. 5-8

8. In order to reduce the concavity of the bend, a thick iron bar is placed on the

marked region. It is then pressed by using the bending tool. The image

below shows this procedure.

72

Fig. 5-9

9. The edges are then straightened, which get deformed due to bending, as

shown below.

Fig. 5-10

73

10. The procedure described above is repeated for all the templates. After

checking all the templates individually all the templates are placed on the

metal plate as shown in the next picture. Magnets are used as shown in the

picture to place the templates.

Fig. 5-12

11. The plate is checked to see if the templates fit exactly. In addition to this the

top edges of all the templates have to be aligned. This is sometimes checked

by using a thread, if the plate is big.

74

Fig. 5-13

Plate after bending.

Fig. 5-14

75

6. ROLLING

Rolling Tools

Fig.6-1

1. Figure 6-1 shows the rolling tool. The part on right is the roller, which is

attached to the stamp which applies the desired pressure to the plate. The

part on the left is rolling die on which sheet is kept, it is attached through

cables to the machine, this thing moves the sheet by rolling itself at desired

speed.

2. Figure 6-2 shows how the operator is marking the rolling area. The area

enclosed within the box is called the rolling area. It tells the operator where

to stop rolling, it acts as a boundary line. Since, the sheets are rolled at very

pressures, so if the operator just over rolls the sheet then the sheet will bang

76

against the wall ahead at very high speed. That why, just prevent any

accident the rolling area is marked.

Fig. 6-2

Figure shows that the sheet needs to be rolled by applying a pressure of

30 tons.

Fig. 6-3

77

Figure shows a plate being rolled.

Fig. 6-4

Some important data:-

Pressing:

78

Rolling:

Diameter cylinder (cm): D 34

Pressure (bar): P 119

diameter rod (cm) d 32,00

Pressure (bar): P 70,00

Surface (cm²): V = ¼ * π * D² 907,92

Surface bottom - rod (cm²): V = (¼ * π * D²) - (¼ * π * d²) 103,67

Force bottom (ton): F = (V * P) / 1000 108,04

Force rod (ton): F = (V * P) / 1000 7,26

pressing force 100,79

The overall steps remain same only the tool changes for different operations

like Rolling, Flanging, Stretching and Punching.

Different plates require different tools for bending. Bilge plates require

rolling whereas, Shell plates require only bending. Bottom plates do not

require bending. Some of them are mentioned in the table below:-

Rolling

Block No: Plate No:

140 57,58,59

410(P),411(S) 76,77

370(P),371(S) 87,88

310(P),311(S) 74,75

320(P),321(S) 165,166

79

360(P),361(S) 83,84

380(P),381(S) 94,95

Stretching & Punching

Bending

Block No: Plate No:

520 124,125,126,127,128,129,130,131,132,133,134,1132

530 117,116,

515 113,114

510 105,106

(stretching) 131 54,55,56,63,68,69,71,81,82,108,110,117

(stretching) 481 96,97,98,99

Block No: Plate No:

110 51,52,53,61,62,63,1063

131 68,69,70,71,82,108,134,135,140,141,142,143

171 66,67,185,186,187,1064,1065

515 109,110,111,112,113,114,115

520 124,125,126,127,128,129,130,131,132,133,134,135,136

80

CONCLUSION

The various bending processes and the steps involved in it have been

thoroughly studied. The bending operation is quite skillful and work finish

depends mainly on the operator’s expertise. The complete bending operation

can only be learnt by actually observing the process and practicing it to achieve

perfection. This report can be used as a supplement in the process of learning.

81

Appendix A

When sheet metal is bent, it stretches in length. The bend deduction is the

amount the sheet metal will stretch when bent as measured from the outside. A

bend has a radius. The term bend radius refers to the inside radius. The bend

radius depends upon the dies used, the metal properties, and the metal

thickness.

Many software packages refer to the K-factor for bending sheet metal. K-factor

is a ratio that represents the location of the neutral sheet with respect to the

inside thickness of the sheet metal part. The bend allowance is the length of the

arc of the neutral axis between the tangent points of a bend in any material.

BD = 2*(R + T) - BA

BA = π*(R + K*T)*A/180

K = (180 * BA)/ (π*A*T) - R/T

Where:

BA = bend allowance

R = inside bend radius

K = K-Factor, which is t / T

T = material thickness

t = distance from inside face to neutral sheet

A = bend angle in degrees (the angle through which the material is bent)

82

REFERENCES

We would like to thank the machine operator, Mr. Narayan for his guidance

and for explaining us the bending process.

In addition to this we gathered data from various sources namely:-

1. Operating manual for Nieland SBP-275.

2. Wikipedia – for gathering information on the various types of bending

processes.

3. Quality Manual 1, Chowgule Group.

4. Quality Manual 2, Chowgule Group.

5. Hyspeed ht4400, “plasma arc cutting machine”, Instruction manual

803580-revision.

6. Schwarze-Robitec machine manual.

7. www.nieland.com

8. www.google.co.in

83

GLOSSARY

1. Aback: Front superstructure between main deck and aback deck

2. Aft peak: The back compartment of a ship.

3. Anchor winch: Winch for weighing and dropping the anchor chain.

4. Ballast: It provides moment to resist the lateral forces on a ship’s sail.

5. Bollard or Dead head: Connectors on the high deck to put the hawser

around for putting the ship in branches, mooring etc.

6. Bridge: Bunks for higher officers and passengers, also the navigation

room.

7. Bulwarks: Rail on the deck to protect the cargo and the people from

water and being thrown overboard.

8. Deck: This is the plating for closing the cargo hold completely or

partially.

9. Double Bottom: Room between skin and real bottom for extra safety.

Room contains ballast, oil and water.

10. Forecastle deck plating: This is the plating that closes the hold (the front

superstructure) of a ship.

11. Fore peak: The front compartment for ballast.

12. Hold: room that contains the cargo.

nieland press bending

Documents