Nieland Press Bending
Nieland Press Bending
Nieland Press Bending
ON
THE BENDING PROCESS CARRIED OUT
USING SBP-275.
BY
SHASHANK 2007A1PS395P
AMEYA AMBARDEKAR 2007A3PS114G
ASEEM ROHATGI 2007A3PS171P
AT
BY
SHASHANK 2007A1PS395P B.E Chemical
AMEYA 2007A3PS114G B.E EEE
ASEEM 2007A3PS171P B.E EEE
ZUARINAGAR.
A Practice School-1 station of
BIRLA INSTITUTE OF TECHNOLOGY & SCIENCE,
PILANI.
(JULY, 2009)
2
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.
3
BIRLA INSTITUTE OF TECHNOLOGY &
SCIENCE, PILANI
Practice School Division
SHASHANK 2007A1PS395P
AMEYA AMBARDEKAR 2007A3PS114G
ASEEM ROHATGI 2007A3PS171P
4
Name of the PS Faculty: Dr. RAMESHA C.K
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.
5
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.
Date: -
6
TABLE OF CONTENTS
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
7
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
4. Working methods…….……………………………………………………..63
5. Bending Process…..………………………..……………………….............65
6. Rolling….………...…………………………………………………...……75
Conclusion..…………………………………………………………………….80
Appendix……..……………………………………………………………...…81
References………………………………………………………………...……82
Glossary...…………………………………………………………………....…83
8
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:
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.
9
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.
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.
10
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.
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.
11
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.
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
12
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.
13
1. Cutting Section
1) Work-piece dimensions
2) Tool selection
3) Tool travel
4) Cutting sequence
5) Width of cut (kerf)
6) Feed rates
14
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
15
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
16
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.
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.
17
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.
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.
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
18
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.
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.
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.
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.
19
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
20
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
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
21
Fig.1-9
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
22
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
23
1.5 POWDER MARKING:-
Long extending
white flame with White flame shines Pastel coloured
fading tip on top brightly and the flame and the
of primary flame form is sharp form is sharp
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
Orange-red No colour
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.
SYSTEM SPECIFICATIONS
25
The Long Life Process
26
Basic System Layout
CNC
Ignition
Console
O2 Air N2
Off
Gas Hose Valve
Water
Assembly
Control
(coolant)
Cable
Electrode (-) Torch
Work (+)
Lead
Torch
Lead
Leads
Work Table
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.
27
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.
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:
29
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.
31
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.
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.
34
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.
35
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.
Fig. 2-1
36
The picture shows the table on which die is mounted.
Fig. 2-2
1. Stretching
2. Bending (in one direction)
3. Concaving (in two directions)
4. Small concaving
5. Flanging (square bending)
37
Rolling tools are available for:
The production of steel plates for ships mainly consists of stretching, bending and
flanging, the following tools are used:
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.
38
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
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
39
dependent or position dependent. In most cases the pressure dependent method id
used.
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.
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.
40
Fig. 2-6
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.
41
Pressing Table
Fig. 2-7
42
Fig. 2-8
43
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.
44
3. THE BENDING MACHINE
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 Name
no.
1 Lower bridge
2 Upper bridge
3 Left column
4 Right column
5 Cylinder
45
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
46
Movable Control Desk (MCD)
47
automatic mode.
2 = Crane two in operation in automatic
mode.
26S6 Twisting Selector To turn twisting on/off. When on the
switch 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 Burns when main and auxiliary motor are
lamp on, and blinks when they are starting up.
42H1 Control voltage Indicator Burns when control voltage is present.
lamp
HMI Operator panel Text panel Human Machine Interface = Inputting
device (see chapter 7).
23S6 Start Illuminated When lamp (42H3) blinks it invites you to
push button 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 to turn Hoist 1-1 on/off.
push button Lamp (42H4) burns when Hoist 1-1 is
turned on.
26S2 Hoist 2-1 Illuminated Push to turn Hoist 2-1 on/off.
push button Lamp (42H5) burns when Hoist 2-1 is
turned on.
26S3 Hoist 1-2 Illuminated Push to turn Hoist 1-2 on/off.
48
push button Lamp (42H6) burns when Hoist 1-2 is
turned on.
26S4 Hoist 2-2 Illuminated Push to turn Hoist 2-2 on/off.
push button Lamp (42H7) burns when Hoist 2-2 is
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.
27S2 Hoist 2-1 Control lever 1 click up/down = hoist 2-1 slow speed
hoisting.
2 clicks up/down = hoist 2-1 high speed
hoisting.
28S1 Hoist 1-2 Control lever 1 click up/down = hoist 1-2 slow speed
hoisting.
2 clicks up/down = hoist 1-2 high speed
hoisting.
29S1 Hoist 2-2 Control lever 1 click up/down = hoist 2-2 slow speed
hoisting.
2 clicks up/down = hoist 2-2 high speed
hoisting.
49
Remote control (RC)
50
24S1A Manual Push-button Keep pushed to enable manual control
temporarily
13S3 Emergency Push-button Push to stop the complete installation
stop (emergencies only)
51
23S1A Push-button Decrease stop-position with 0.1 mm
23S2/ Push on Increase stop-position with 0.1 mm
3A button
When both buttons are pressed simultaneously the stop-position will be stored
52
When both buttons are pressed simultaneously the stop-position will be stored
(teach in)
53
THE OPERATOR PANEL:-
Introduction
The front view of the operator panel OP7.
OP7
When the electric system is turned on, the following text will appear on the
display:
TOTAL HOURS IN The start-up text when the electric system is turned on.
OPERATION: Hour counter.
OIL TEMP. : DG.C Oil temperature in °C.
55
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;
TABLE/TOOLS ROTATION
ACT. ANGLE : DGR Current angle of the table support.
DGSPEED : % 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
56
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.
TABLE/TOOLS ROTATION
ACT. ANGLE: Current angle of the table support.
ADJ. ANGLE : 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
CURRENT : Current position of the ram in respect to the upper
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position (read only).
STOP : Stopping position (20.0-480.0 mm) in respect to the
upper position.
STROKE : 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:
By pushing the "▼"-key again several times the next window will appear:
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Type with the numeric keys the desired value
PRESSING
CURRENT (TON) : Current pressure in metric tons.
STOP (TON) : Stopping pressure (0-275TON).
STROKE (MM) : 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:
By pushing the "▼"-key again several times the next window will appear:
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TR. CRANE (SEC) : Travelling time (0.00-10.00 sec) of the crane(s).
TR. TROLLEY (SEC) : Travelling time (0.00-10.00 sec) of the trolley(s).
CRANE L. SP (%) : Crane low speed (0-100 %) = auto travelling speed.
CRANE H. SP (%) : Crane high speed (0-100 %), only in manual control
available.
ROLLING
CURRENT (MM) : Current position of the ram in respect to the upper
position.
STOP (MM) : Stopping position (20.0-480.0 mm) in respect to the
upper position.
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
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“STOP”-position can be in- or decreased in steps of 0.1 mm. By pushing the "▼"-
key several times the following text will appear:
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
CURRENT (TON) : The current pressure.
STOP (TON) : The stopping pressure.
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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:
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.
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4. WORKING METHODS
WORKING METHODS
PRESSING ROLLING
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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
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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.
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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.
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
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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
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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.
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The image on the following page shows that the plate needs to be bent from
the sides.
Fig. 5-5
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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
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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.
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Fig. 5-9
9. The edges are then straightened, which get deformed due to bending, as
shown below.
Fig. 5-10
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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.
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Fig. 5-13
Fig. 5-14
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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
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against the wall ahead at very high speed. That why, just prevent any
accident the rolling area is marked.
Fig. 6-2
Fig. 6-3
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Figure shows a plate being rolled.
Fig. 6-4
Pressing:
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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
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
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360(P),361(S) 83,84
380(P),381(S) 94,95
Bending
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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.
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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)
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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:-
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GLOSSARY
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