Parts and Functions of Press Brake You Should Know

Press Brake Structure Drawing

Generally, the press brake machine includes four main parts:

  • Mechanical parts
  • Electrical parts
  • Hydraulic parts
  • NC/CNC controller

And the following describes the details and functions of each part, let’s dive into it.

Press brake body

Press Brake Frame

The frame of the press brake is welded by the left and right upright plate, worktable, supporting bodies and fuel tanks.

The worktable is under the left and right uprights. The fuel tank is welded with the uprights, which can improve the rigidity and strength of the frame, as well as increase the heat dissipation area of the hydraulic oil.

Features of Press Brake Structure:

  • Adopt a fully welded structure, with sufficient strength and rigidity;
  • Up transmission of hydraulic oil, the cylinders on both ends of press brake are installed on the slider, directly drive the sliding work;
  • Slider adopt torsion to force synchronization;
  • Adopt mechanical stopper, stable and reliable;
  • Slider stroke is adjusted by the controller, fine adjustment manually, counter display;
  • Wedge-shaped crowning, to ensure a higher bending accuracy.

Further reading:

Press brake ram

The ram is made from the whole steel plate and is connected with the piston rod in the center of the left and right oil cylinder.

The cylinder is fixed on the connecting plate of the left and right wall plate, and the piston rod is driven by the hydraulic drive to move the slider up and down.

In order to ensure the accurate positioning of the ram in the upper dead point, a grating ruler is arranged on both sides of the ram to transfer the position information back to NC controller, and the position is adjusted by the controller.

At the same time to ensure the synchronous operation of the ram.

The ram adopts hydraulic transmission and the ram system consists of the slider, oil cylinder and mechanical stopper for fine adjustment.

The left and right cylinders are fixed on the frame, and the piston (rod) is driven by the hydraulic pressure to move the ram up and down.

The mechanical stopper is controlled by the numerical control system.

Further reading:

Press brake worktable

The forward and backward movement of the back stopper is driven by the motor, and the moving distance of back stopper is controlled by CNC controller, with minimum reading 0.01mm (there is stroke limit switch both at the front and back position).

Further reading:

Synchronization System

The mechanical synchronization mechanism consists of torsion, swing arm, joint bearings etc.

It has a simple structure, stable and reliable performance, as well as high precision synchronization.

The position of the mechanical press brake stops is adjusted by the motor, while the data is controlled by the CNC controller.

Further reading:

Press brake back gauge

The back gauge of the CNC press brake adopts motor driving transmission, to realize synchronous movement by two ball screws and timing belt.

The backgauge distance is controlled by the CNC controller.

Press Brake Axis

Press Brake Back Gauge

Press Brake Back Gauge-MachineMfg

Press brake axis:

X, Y, Z directions of press brake are as follows, the arrow in the figure is positive.

Press Brake coordinates

Press brake axis can be classified as follows:

Y1—the left cylinder of the ram;
Y2—the right cylinder of the ram;
W-lower beam convex compensation cylinder (ie deflection compensation system);
X, X1, X2—move back and forth of the back gauge;
R, R1, R2—moves up and down of the back gauge;
Z, Z1, Z2—move left and right of the back gauge;

Note: The ram position can be programmed by an absolute value equation or the angular value;

Press Brake Axis Diagram

The position of each control axis of the press brake is shown in the table below:

AxisZero positionActual value
Y1 ram left(Up or down)Work surfaceDistance from the surface of the table to the upper die
Y2 ram right(Up or down)Work surfaceDistance from the surface of the table to the upper die
X、X1、X2 backgauge〔back and forth〕Lower die centerMaximum distance from the center of the lower die to the back gauge
R、R1、R2 backgauge(Up and down)Lower die surfaceThe distance from the lowest point of the back gauge to the highest point of the back gauge
Z1 backgauge left〔Left to right〕Machine left sideThe distance from the leftmost side of the machine to the center of the left backgauge head
Z2 backgauge right(Right to left)Machine right sideThe distance from the rightmost side of the machine to the center of the left backgauge head

Press brake front support

The front supporter arms of the press brake are fixed on the T-groove or linear guide in front of the machine and are designed with a manually adjusted back position claw.

Press Brake Work Support Arms

Press brake pedal switch

The pedal switch of the press brake is mainly used to control the up and down of the top punch during bending operation.

There is also one emergency button on top of the pedal switch for emergencies.

Press Brake Foot Pedal Switch

Press brake punch clamps

Press Brake clamps including normal standard clamps and fast clamping tools for quick change of the top punch.

Clearly, fast clamping tools will make it much easier for change punch die, not only convenient but also time-saving.

Press Brake Clamps

Further reading:

Kits and accessories

1User Manual1 Copy
2Foundation Screw4 Pieces
3Washer4 Pieces
4Oil Gun1 Set
5Front Supporter2 Pieces
6Pedal Switch1 Set

Press brake guarding

Generally, the press brake will be equipped with a steel fence to protect the workers from injury.

If you want to have better safety assurance, then you can consider using a light curtain safety device and laser protection device.

Press Brake Laser Protection

As I know, the safety of the machine must reach a certain degree, otherwise, it’s forbidden to use it.

So I suggest you equip the press brake with at least light curtain device for safety considerations.

Press Brake Safety Guards

Press Brake Safety Guards

Press Brake Light Curtains

Press Brake Light Curtains

Press Brake Laser Guard

Press Brake Laser Guard

Further reading:

Press brake gauge

The commonly used press brake gauge including angle gauge, angle ruler and venier.

Press Brake Gauge

Press brake electrical system

Press brake power supply using three-phase AC 50HZ 380V power (can be customized), can not only be directly used for the main motor operation, but also for the rear gear servo and equipment lighting use after output AC voltage through the system internal transformer.

The other group form into two sets of DC 24V after rectification, one way for CNC controller use, the other for the use of controlling loop.

Press Brake Electrical System

Wiring diagram

Different manufacturers will design different press brake wiring diagrams.

When you purchase it, the suppliers will send you the wiring diagram together with the hydraulic diagram as well as the installation and operation manuals.

If you did not see it when you receive the machine, please contact your supplier immediately.

The following press brake wiring diagram is from us, just for your reference.

Press Brake Wiring Diagram

Press brake hydraulic system

Press Brake Hydraulic System Working Principle

Press Brake Hydraulic System Working Principle

The motor, oil pump, valve are connected with the fuel tank, in order to ensure that the oil tank is filled with oil when the ram is rapidly falling, the structure of the filling valve is adopted, which will not only improve the travel speed of the ram but also save energy.

The hydraulic control of CNC press brakes requires a high degree of automation and standardization rate in manufacturing.

Therefore, the press brakes must integrate the hydraulic system into it.

The frame of the press brake becomes the basis for the installation of hydraulic parts and integrate the oil tank into the stamping frame.

Three control block style

It has three control blocks.

Two with the middle plate filling valve and the main control block directly installed in the hydraulic cylinder in order to achieve the pipe-free connection between the main control block and the hydraulic cylinder.

The back pressure assembly consists of a reversing seat valve and two relief valves, corresponding to the customer’s requirement as a non-leaking type.

The main installation here is the proportional relief valve and a maximum pressure shut off valve, as well as monitor the reversal valve at the position of the pilot valve.

Press Brake Hydraulic Block

Central control block

The central control block combined three control blocks into one which is mainly used in some special structure due to control reasons.

The control block and the connection between the two hydraulic cylinders must in a symmetrical layout.

It uses an SFA series of oil filling valves.

The valve is in a flange structure, directly installed in the hydraulic cylinder, and connected to the tank by a suction pipe.

Sensor and axis interface distributor

All the solenoid valves are concentrated in a control block. Similarly, the electrical connections of the valves are also concentrated on a single cable to achieve a common connection.

For this purpose, an interface distributor is provided on the central control block.

Press Brake Valve

Hydraulic Oil Cylinder

Hydraulic Oil Cylinder

Further reading:

Clean the Hydraulic Oil

The hydraulic system has a high requirement for the cleanliness of hydraulic oil. The cleaning of the oil tank is very important.

When replacing the hydraulic oil, you must discharge the cover of the oil tank.

Use the towel to clean the bottom of the tank (do not use cotton yarn), then wash with cleaning coal oil gasoline.

For the limitation of the tank cover, the arm cannot reach the end of the tank; you can wrap the towel on the bamboo or stick to wipe each corner.

Loosen the leaking plug or brake valve to leak out the dirty oil.

Use the cleaning towel to dry the sides and bottom of the tank until it’s clean.

If necessary, roll the dough at the welding seam or difficult cleaning places to cling the dirt, and then put on the cover.

Further reading:

Press Brake Hydraulic System

Press brake hydraulic oil selection

Recommended hydraulic oil for press brake

Recommended hydraulic oil for press brake

The mark value of hydraulic oil is equal to the average value of viscosity when the temperature is 40℃.

If the working pressure and temperature of the hydraulic system are higher, and the working speeds slower, the chose hydraulic oil mark is higher.

It is recommended to use antiwear hydraulic oil ISO VG46# (the average value of viscosity is46mm2/s, when the temperature is 40℃.).

If the machine operates under 5℃ for a long period, you can choose hydraulic oil ISO VG32#.

It is also recommended not to use the machine at very low temperatures (below -5°).

However, should this occur, and then let the machine run idle for a while. An oil heater can be fitted in the circuit if required.

Under normal working conditions, the oil temperature must not exceed 70℃.

Under special conditions, an oil cooler can be fitted as necessary.

Further reading:

Fill the oil

The using oil must be clean.

Screw the nut of the air filter, filling through the air filter. If using the filling equipment with a filter, you can open the cover of the oil tank and fill directly.

Observe the oil gauge, when the ram stops at Top Dead Spot, the hydraulic oil fills at 80~90% of interspaces.

Make the machine work, first idling then at the maximum stroke to expel any air bubbles in the hydraulic circuit.

Oil Tank Capacity

NC press brake oil tank capacity chart

ModelOil Tank Capacity

CNC press brake oil tank capacity chart

ModelSS Tank
MS Tank

Oil Seal Ring

The oil seal is also a very critical part of the press brake machine.

Press Brake Seal Ring

Further reading:

Press brake weight

The weight of the press brake ranges from 5T to 300T, this is much depending on the size of the machine.

For example, for 80T/2000mm press brake, the weight is around 6T, however, the weight for 2000Tx12000mm press brake is over 300T.

Press Brake Weight

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