Operational Manual
Hydraulic
MB8-300T3200
Press Brake
Nominal pressure: ---3000----KN
Length of Workbench: ---3200----mm
Maanshan Durmapress Machinery Technology Co.,Ltd
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CONTENTS
1 Brief Drawing of the Machine ----------------------------------------------------2
2 The Main Parameters of the Machine ------------------------------------------3
3 The Use and Characteristics of the Machine ----------------------------------4
4 Introduction of the Machine’s Structure----------------------------------------6
5 Hydraulic System-------------------------------------------------------------------14
6 Electrical System--------------------------------------------------------------------17
7 Transfer and Installation of the Machine -------------------------------------19
8 Lubrication of the Machine-------------------------------------------------------21
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9 The trial running and Operation of the Machine ---------------------------22
10 Adjustment of the Machine-----------------------------------------------------23
11 The Technology for Safe Use and Maintenance of the Machine---------25
12 Chart of Bending Force ---------------------------------------------------------26
13 Wearing Parts ---------------------------------------------------------------------27
Technical Date
No. Item Count Unit Remark
value
1 Nominal pressure 3000 KN
2 Length of workbench 3200 mm
3 Width of workbench 270 mm
4 Distance between upright 2600 mm
columns
5 Throat depth 400 mm
6 Max ram stroke 200 mm
7 Max open distance between 450 mm
workbench and ram
8 Max distance of backgauge 600 mm
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9 Motor of Model YS5264 /
Bloke Rotation rate 1400 r/min
adjusting Power 370 KW
10 Model Y132M-4 / B35
Motor of oil Power 22 KW
Pump Rotation rate 1400 r/min
Model YS-8206 /
Backgauge
Power 0.75 KW
11 adjusting
Rotation rate 1140 r/min
motor
Rated 31.5 Mpa
12 Gear pump Pressure
Flow 50 L/min
Model CP1-50-P-10R /
13 The highest working pressure 20 Mpa
of hydraulic system
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Exclusive
14 Overall Dimensions( L×W×H) 3200X1800X m of front
3000 m support
15 Gross weight 14500 Kg
The Use and Characteristics of the Machine
(1) Use
The machine is a kind of general equipment used for completing metal bending. It can
compress metal sheet into a certain geometric shape through simpler common molds.
When bending the sheet metal of different thickness and shape, you should make the
options of corresponding shape of V-shape lower die of different opening size. The
bending force can be figured out from the Bending Force Table or the Formula of the
Bending Force Calculation.(refer to figure 17)
By using different shapes of molds, it can bend workpieces into various shapes (refer to
figure 2). Meanwhile it can be used for punching, pressure ripple, light stretching and so
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on if it is equipped with the corresponding process devices. So the machine is widely used
for electrical appliances, automobiles, shipbuilding, daily-use hardware, machinery
manufacturing and other process departments.
（2） Characteristics
1 Cylinders at the two ends are placed on columns at the both sides which directly drive the
ram work. The machine’s structure is simple and the rigidity is excellent.
2 The machine adopts steel torsion bar to maintain the ram’s synchronization; the ram also
can withstand a certain degree of partial load.
3 The machine adopts configuration welded with steel plates which has high strength and
excellent rigidity.
4 To meet the need of free bending, the ram’s downward stroke is adjusted by mechanical
block(refer to figure 3); to control the stroke of ram, the upper limited position of ram is
adjusted by upper stop-point block of the ram(refer to figure 5)
5 The linking parts of the upper die is equipped with compensation mechanism which is
capable of compensating deflection of workbench and ram while bending and ensures the
workpiece to achieve high bending accuracy.
6 The machine adopts electrical hydraulic control, so the ram can be adjusted freely with
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single stroke, recurrent stroke, inching and half-way stop operation and it is easy to
realize automotive operation.
7 There is powroff device between the door of electric box and the ark which ensures the
safety of operation and maintenance. As long as you open the door of electric box the
power will be off.
4 Introduction of the Machine’s Structure
The machine is made up of 9 parts, including the body, the torsion bar, the ram, the stroke
adjustment, the front support bracket , molds, the hydraulic system and electrical system
1 The body(refer to figure 1)
The machine is welded with right and left upright columns, beams and the front and rear
bearing which ensures it to achieve a high rigidity and accuarcy. A plate is welded on the
top of right and left columns which is used to fix the right and left cylinders; A piece of
iron is installed at the lower part of the columns to increase the contcat area to prevent the
dumping of the machine in the hauling process which can be removed after mounting.
2 Ram and the adjustment of stroke(refer to figure 3,4,5)
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The ram is made from single piece steel. The right and left cylinders are fixed on their
corresponding columns and are connected with the ram through the piston rod. The
cylinder is fixed on the body of the machine and makes the piston rod drive the ram to run
through hydraulic-drive. In the cylinder there are mechanical blocks which control the
lower limited postion of the ram. The location of mechanical block is adjusted through the
worm gear drive and displayed by Stroke Counter L.
3 Synchronous System
The Synchronization during the running of ram adopts torsion axis synchronous system
with the torsion axis connected with the ram which is simple, steady and reliable.
4 Front support carrier（refer to figure 6）
5 Back block carrier （refer to figure 7）
Through the adjustment of front and back position of the block carrier, the back
positioning of workpiece can be realized. The position of block carrier is adjusted
initially by mechanical transmission systems and then carried out fine-tuning by handle.
The carrier’s position is displayed by digital tubes. In cases that the displayed value is not
consisted with the actual measurement, you can modify the system to make the vaule be
consisted with the actual size. The modification of the system’s X axis is carried out on
PAC01 and press the right button to realize . The block carrier is equipped with
embossing nut. The block rod can move up and down which keeps it at the same level
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with the top of lower die.
6 Mold（refer to figure 8）
Plate that is uesd for quick connecting mold is installed on the upper part of the upper die.
The upper die can have a slight displacement in the vertical direction through the adjustment
of bevel iron’s right and left position. By adjusting the position of each bevel iron, the
opening of the upper die can obtain a specific curve over the full length of the machine
which can compensate the defection generated over the workbench and ram during the
loading of the machine. Moreover, it can effectively improve the bending accuarcy.
7 Hydraulic System
With the hydraulic system, the ram can achieve idle running, ram’s fast descending, ram’s
slowly descending and the ram’s pullback .
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8 Electrical System
There are various operation button in the electric box (refer to figure 11). The electric box is
equipped with mechanical lock so you should cut off the power when opening the box’s door.
If it need to be checked and manitaned in the power on condition, you can manually reset.
5 Hydraulic System
The system enables various activities including the ram’s fast and slow descending, working
speed bending, fast pullback and urgent stop during descending process.
With the power supply is switched on to start the motor，hydraulic oil returns to the oil tank
via the electromagnetic overflow valve and the pump is idle running.
When pressing feetswitch and the ram runs downwards ,YV1 and YV4 are in the power.
The pressure oil enters the upper cavity of the oil cylinder via electromagnetic reversing
valve and the throttle hole(d3.2). The hydraulically controlled one-way valve opens because
of the increase of the pressure before the throttle hole. Hence the ram descends rapidly due
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to its own gravity and oil’s pressure.The oil in the lower cavity of the oil cylinder returns to
oil tank via hydraulically controlled one-way valve, electromagnetic reversing valve and the
throttle hole. During the course of ram’s rapid descending, the upper cavity becomes
vacuum and be filled with oil through one-way valve. When the stroke switch SQ1(refer to
figure 5) and YV2 and YV5 are in the power, the ram’s rapid descending changes to slow
descending due to effect of the throttle hole . when the ram reaches the upper die and
contacts the workpiece, it bends the workpiece under the pressure at working speed. When it
descends to the preset position, the mechanical block in the cylinder prevents it to decline
and makes it stop there and the pressure oil returns to the tank via overflow valve.
When pressing feetswitch, YV1 and YV3
are in the power. The pressure oil enters the lower cavity of the cylinder via
electromagnetic valve and the throttle hole which pushes the piston rod to drive the ram to
go upwards. The oil in the upper cavity returns to oil tank via electromagnetic valve and the
throttle hole. When the ram runs upwards till it reaches the stroke switch’s SQ2 and touches
the top stop block, YV1 and YV3 are power off and hydraulic oil returns to tank via
electromagnetic overflow valve. Then the ram stops and the pump turns to be idle running
again.
Remote pressure regulating valve can adjust working pressure. The valves’ pressure that
need to be adjusted are as follows:
Overflow valve 5 adjusted pressure 23MPa
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remote high-pressure valve 9 adjusted pressure 3-23MPa
6 Electrical System
1 Characteristics（refer to electrical principle）
(1) The machine adopts three-phrase AC 220V/60HZ. AC 24V and 29V used by circuit is supplied by transformer
within the machine
(2) Electrial box is equipped with mechanical lock. So once you open the lock the power will be off automatively.
(3) The breaker and overload of main electric circuit is protected by automative breaker QF1.
(4)When the machine running in the mode of “inching operation” and “single stroke”, it functions
footswitch. The mode of “recurrent stroke” is realized by lock transformation.
(5) When the ram stops at lower limited position, the machine’s pressure maintaining is carried out by KT1.
And the pressure release is carried out by KT2 before the ram going upward.
(6) Only when the ram stops at the upper limited position(SQ2-1), you can start the motor of backguage and
the motor of the stroke.
(7)When the machine is not running, you should put the button of manual operation and foot operation to
the manual position and then pull out the lock.
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2 Adjustment and operation of Electrical System
Connect three-phrase power cords with the input terminal（L1、L2、L3）and QF1 and then close the door of electric
box.
(1) Firstly, start the motor of oil pump for a short while in order to check if the rotation direction is correct or not.
If adjustment is reqired, you can change the input power cord’s order, but never change any wiring within the
machine itself.
(2) The operation should be processed according to the operation prodecure.
(2.1) Inching operation
Put the SA2 to the middle position and then start the oil pump.
(2.2) single stroke
Put SA2 to the position of “single stroke” and then start the oil pump. Press the pedal downwards and at that time
the ram goes downward and stops till it contacts the mechanical block. when the pressure maintaining time
(adjusted by KT1) is over, YV1 upload the pressure(adjusted by KT1) and two seconds later, the ram goes upward
automatively and stop at upper limited position and stops there.
(2.3) recurrent stroke
Turn the button SB1. Then once you put SA2 to “recurrent stroke” position and press the feetswitch downwards,
the ram moves upward and downward repeatly. If you want to stop the ram, you can put SA2 to the position of
“inching operation” or “single stroke”
（ 3 ） The adjustment of backgauge’s distance: press button SB5 and SB6, the backgauge moves forward and
backward
(4) Press button SB3 & SB4 to adjust the running of the ram
(5) Press the urgent stop button of the electric box , the machine will stop any operation
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9 THE TRIAL RUN AND OPERARION PROCEDURE
1 Preparation for Trial Run
①The preson who operates the machine must read the instruction manual carefully and acquaints
with the main structure, peformance and the use of the machine.
②Fill the oil tank with hydraulic oil N32-N46 till the level reaches the engraving line.
③Connect with the power supply line and ensure the direction is right.
④Release the handle of the remote adjusting valve( tightening it gradually during the trial run to
improve the pressure of the sysytem).
⑤Twist the switch to the "inching operation” position and start the trial run.
2 OPERATION PROCEDURE
①Two operation molds to control the running of ram, by hand or feet, which supports inching
operation, single and recurrent stroke. So the trial run must be done seperately according to
different operation molds.
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②When trial run, the machine must firstly operate without load; then operate with load and
increase the bending force gradually till up to its max load capccity.
③Start the motor of block adjusting (refer to figure 3); the lower limited position changes
correspondingly when the ram going downward;the position of lower limited position is displayed by
stroke counter I and the max displayed value should not be more than 105 mm.
④When pressing button SB3 or SB4 in the button box(refer to figure 7), the backgauge carrier
moves forward or backward. The distance of backgauge is displayed by the counter II in the
button box.
In the process of trial run, please check weather all the running sections are flexible ,reliable and
in normal condition. Make sure there is no leakage at seals and linking parts.
10 ADJUSTMENT OF THE MACHINE
1 Adustment of Workbench and Ram’s Parallelism
We have adjusted ram’s parallelism for you when the machine left the factory, so you do not
have to adjust it again. If you want to adjust it yourself, the adjusting procedure is as follows:
firstly, stop the ram on the upper part of the machine; then adjust the stroke of mechanical
block in the oil cylinder at both ends to be consistent; to achieve that, firstly you should
release the connecting rod and turn the worm rod on the right. At that time the position of
mechancial block changes slightly. Following, move the ram to its lower limited position and
check the parallelism of workbench and ram. Finally link the connecting rod.
2 Adjustment of Machine’s Angle
Use ram adjustment device(refer to figure 3&4). Start the motor of block adjustment and
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when the value displayed by the counter is decreaseing, the ram’s lower limited position
descends and the bending angle increases. Adjusting range is diaplayed by stroke counter
and it can accurate to 0.1mm.
3、Adjustment of ram’s upper stop position
Decline the position of the block of ram’s upper stop point, the ram’s upper stop point rises.
Otherwise it descends.
4、Adjustment of velocity-change point(refer to figure 5&9)
When moving block of adjusting ram’s descending slowly downward, stroke switch SQ2 acts
ahead of time and YV3 is power on. With the throttling effect of the hole within the machine ,
the ram descends fast. With the declining of block of adjusting ram’s descending slowly, the
distance of slow descending increases correspondingly;otherwise the distance decreases.
5 Adjustment of Bending Force
When the ram goes downward till the upper die contacts the lower die, turn the handle of
remote adjusting valve and then the system’s pressure will change correspondingly. The
corresponding relation between system’s working pressure and machine’s bending force
can be figured out from figure 17.
6 Adjustment of pressure maintaining while bending
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Pull the equipment for delay cnotrol in electeic box (refer to the operation instruction of
ACM-C1) , when the value of the equipment for delay cnotrol increases, the time for
pressure maintaining extends, otherwise the time decreases.
11 The Technology for Safe Use and Maintenance of the Machine
Whoever before operating and repairing the machine must read this instruction carefully and
follow these guidance. This machine will prove to be a dependable and useful aid for
working with sheet metal and plates.
The machine must be taken care of by a person specially assigned. The person who operates
and maintanes the machine should learn how to operate and follow the precaution
regulations for the sake of safety .
1 The bending force should not exceed the machine’s nominal pressure.
2 For extending the life span of dies, be careful to choose the appropriate bending width.
Particularly, when bending narrow plates, you should lower the working pressure to some
extend properly and ensure the bending load be less than following value for each 1 meter.
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The load of the bender UNIT：KN
the length of workbench 2500 3200 4000
the load of the bender 350 312 250
3 Choosing suitable mold opening according to different thickness of metal sheet. The size of
mold opening should generally be equal to or over 8 times of the thickness of sheet. The
bending force can be achieved by chart of bending force(refer to figure 18) or by formula
of bending force calculation.
4 Basically, the plate to be bended should be put in the middle of the machine rather partial
load. Meanwhile, avoiding the machine from single-side load which could possibly affect the
precision of the work pieces and the machine itself. If it really requires working on single
side , the load of it must less than 1/4 of the machine’s nominal pressure. Anyway, you
should bend
the plates on both sides simultaneously. The tank applies hydraulic oil N32-N46; the oil
used for the first time should be replaced for one or two times during the first 3 months; the
temperature of oil under normal working condition is 15℃ to 60℃; clear the net oil filter
frequently to keep the oil-absorbing smooth, otherwise there will be vibration when the
pump driving.
5 When adjusting the stroke of ram, firstly you must put the ram at the upper limited position
of the machine(refer to figure 3 & 4); when starting motor of block adjusting, the block moves
up and down; the max adjusting distance is 140mm; observing continually and once there is
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something abnormal, stop the machine and check.
6 Keep the machine itself clear ; the machine should be lubricated at separate points
depending on working condition ; check the oil level in the tank and once there are something
abnormal, stop the machine and check.
7 The bevel iron installed on the top of upper die is used for adjusting the gap between upper
and down die. Before using, the gap between upper and lower die should be properly adjusted
which can ensure each bending angle is the same with others.
8 check and maintain the machine regularly.
Wearing Parts
No. Title Name&Specification Quantity Remarks
1 JB/T7942.1-1995 Strut-type oil gun 1
2 GB1235-1976 O type sealing ring 11×1.9 5
3 GB1235-1976 O type sealing ring 30×3.5 1
4 GB1235-1976 O type sealing ring 35×3.5 1
5 JB982-1997 O type sealing ring 45×3.5 2
6 JB982-1997 Resultant washer 14 10
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7 JB982-1997 Resultant washer 22 8
8 JB982-1997 Resultant washer 33 6
9 JB982-1997 Resultant washer 33 4
No. Title Name&Specification Quantity Remarks
1 WC67K Hydraulic Press Brake 1
2 GB799-1988 Bolt M20×400 4
3 GB6170-2000 Muff M20 4
4 GB97.1-1985 Washers ф20 4
5 JB/T7942.1-1995 Lever type grease gun 1
6 YDT1-14 Foot switch 1
7 Front support carrier 2
8 GB3542.1-1992 O type sealing ring 38 ×3.5 1
9 GB3542.1-1992 O type sealing ring 44×3.5 1
10 GB3542.1-1992 O type sealing ring 60×3.1 2
11 JB982-1977 Resultant sealing ringф14 5
12 JB982-1977 Resultant sealing ringф18 2
13 JB982-1977 Resultant sealing ringф27 6
14 JB982-1977 Resultant sealing ringф42 4
15 Operation instruction manual 1
16 Certificates 1
