Parts and Functions of Press Brake You Should Know

Are you looking to learn more about press brake machines and how they work? If so, you’ve come to the right place.

Press brake machines are essential in the manufacturing industry, used for bending and shaping metal into various shapes and sizes. But have you ever wondered what components make up a press brake machine and how they work together to achieve precision and accuracy?

In this article, we will explore the four main components of a press brake machine, including mechanical, electrical, hydraulic, and NC/CNC controller parts.

We will delve into the structure of the press brake body, the worktable, and the synchronization system, as well as the various press brake axes and their functions.

Additionally, we will discuss the role of the pedal switch, punch clamps, guarding, and gauge, as well as the electrical system and wiring diagram.

By the end of this article, you will have a comprehensive understanding of press brake machines and their essential components, enabling you to make informed decisions about their use and maintenance.

So, let’s dive in and explore the fascinating world of press brake machines!

Press Brake Structure Drawing

The press brake machine typically comprises four main components:

  • Mechanical parts – These parts are responsible for the physical movements of the machine, including bending and shaping the metal.
  • Electrical parts – These parts control the electrical aspects of the machine, such as powering the motor and operating the lights.
  • Hydraulic parts – These parts are responsible for the hydraulic system of the machine, which includes the pump, valves, and cylinders that provide the necessary force for bending and shaping the metal.
  • NC/CNC controller – This component is responsible for the control and automation of the machine, using numerical control (NC) or computer numerical control (CNC) technology.

Let’s explore each part in more detail.

Press brake body

Press Brake Frame

The press brake‘s frame is constructed from the welding of the left and right upright plates, the worktable, supporting bodies, and fuel tanks. The worktable is positioned beneath the left and right uprights, while the fuel tank is welded with the uprights.

This design enhances the frame’s rigidity and strength, as well as expands the area for the dissipation of heat from the hydraulic oil.

Features of the Press Brake Structure:

  1. The fully welded structure provides sufficient strength and rigidity.
  2. The hydraulic oil is transmitted upwards, with the cylinders on both ends of the press brake installed on the slider, which directly drives the sliding work.
  3. The ram uses torsion to ensure synchronization.
  4. A mechanical stopper is used, providing stability and reliability.
  5. The ram stroke is adjusted by the controller and can be fine-tuned manually, with a counter display.
  6. The wedge-shaped crowning design ensures higher bending accuracy.

Further reading:

Press brake ram

The ram of the press brake is constructed from a solid steel plate and is connected to the piston rod in the center of the left and right hydraulic cylinders. The cylinder is secured to the connecting plate of the left and right wall plates and the piston rod is driven by hydraulic power to move the slider up and down.

To ensure accurate positioning of the ram at the upper dead point, grating rulers are placed on both sides of the ram to transmit position information back to the NC controller, which then adjusts the position. This also ensures the synchronized operation of the ram.

The ram utilizes hydraulic transmission and its system consists of the slider, hydraulic cylinder, and a mechanical stopper for fine adjustment. The left and right cylinders are attached to the frame, and the piston is driven by 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 back stopper moves forwards and backwards through the operation of a motor, and the CNC controller controls its moving distance with a minimum reading of 0.01mm. There are stroke limit switches at both the front and back positions to limit the movement of the back stopper.

Further reading:

Synchronization System

The mechanical synchronization mechanism is made up of components such as torsion, swing arm, and joint bearings. It has a straightforward design, provides stable and reliable performance, and boasts high synchronization precision.

The position of the mechanical press brake stops is adjusted through the operation of a motor, and the data is controlled by the CNC controller.

Further reading:

Press brake back gauge

The CNC press brake‘s back gauge uses motor-driven transmission to achieve synchronized movement through the use of two ball screws and a timing belt. The back gauge’s distance is controlled by the CNC controller.

Press Brake Axis

Press Brake Back Gauge

Press Brake Back Gauge-MachineMfg

Press brake axis:

The directions of the press brake in the X, Y, and Z axes are indicated by the positive arrow in the figure.

Press Brake coordinates

The press brake axes can be categorized as follows:

  • Y1: the left cylinder of the ram
  • Y2: the right cylinder of the ram
  • W: the lower beam’s convex compensation cylinder (i.e., the deflection compensation system)
  • X, X1, X2: the back gauge’s back-and-forth movement
  • R, R1, R2: the back gauge’s up-and-down movement
  • Z, Z1, Z2: the back gauge’s left-right movement

Note: The position of the ram can be programmed using either an absolute value equation or an angular value.

Press Brake Axis Diagram

The location of each control axis of the press brake is presented 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 support arms of the press brake are attached to the T-groove or linear guide located in front of the machine. They have been designed with a manually adjustable back position claw.

Press Brake Work Support Arms

Press brake pedal switch

The pedal switch of the press brake primarily serves to control the movement of the top punch during the bending operation, raising and lowering it. Additionally, there is an emergency button located on top of the pedal switch for emergency situations.

Press Brake Foot Pedal Switch

Press brake punch clamps

The press brake clamps consist of standard clamps and fast clamping tools that are used for quickly changing the top punch. The use of fast clamping tools significantly simplifies the process of changing the punch die, making it not only convenient but also time-efficient.

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

Typically, the press brake is equipped with a steel fence for the safety of the workers. If a higher level of safety is desired, the use of a light curtain safety device and a laser protection device can be considered.

Press Brake Laser Protection

I am aware that a certain degree of safety must be achieved for a machine to be considered safe for use. Given this, I would recommend equipping the press brake with at least a light curtain device for safety purposes.

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 gauges include angle gauges, angle rulers, and verniers.

Press Brake Gauge

Press brake electrical system

The press brake is powered by a three-phase AC 50Hz 380V power supply (which can be customized). This power source can not only be utilized directly for the operation of the main motor, but also for the rear gear servo and for illuminating the equipment after the AC voltage has been output through the internal system transformer.

The power source is then transformed into two sets of DC 24V after rectification. One set is used for the CNC controller and the other for the control loop.

Press Brake Electrical System

Wiring diagram

Different manufacturers may have different designs for their press brake wiring diagrams. Upon purchase, the supplier should provide the wiring diagram, along with the hydraulic diagram and installation and operation manuals. If these are not included with the machine upon receipt, it is recommended to immediately contact the supplier.

Please note that the following press brake wiring diagram is just for reference and is from us.

Press Brake Wiring Diagram

Press brake hydraulic system

Press Brake Hydraulic System Working Principle

Press Brake Hydraulic System Working Principle

The motor, oil pump, and valve are connected to the fuel tank. To ensure that the oil tank is adequately filled with oil during rapid movement of the ram, a filling valve structure is employed. This not only improves the speed of the ram’s travel, but also saves energy.

The hydraulic control of CNC press brakes requires a high degree of automation and standardization in the manufacturing process. As a result, the press brake must integrate the hydraulic system into its design.

The frame of the press brake serves as the foundation for the installation of hydraulic components, with the oil tank integrated into the stamping frame.

Three control block style

The press brake has three control blocks. Two of them, with the middle plate filling valve, are directly installed in the hydraulic cylinder to eliminate the need for piping between the main control block and the hydraulic cylinder.

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

The key components installed in the main assembly include a proportional relief valve, a maximum pressure shut-off valve, and a monitoring system for the reversal valve located at the position of the pilot valve.

Press Brake Hydraulic Block

Central control block

The central control block combines the three control blocks into one, and is mainly used in specialized structures for control purposes. The control block and the connection between the two hydraulic cylinders must be in a symmetrical arrangement.

Press Brake Valve

It utilizes an SFA series of oil filling valves, which are designed in a flange structure and directly installed in the hydraulic cylinder, connected to the tank via a suction pipe.

Sensor and Axis Interface Distributor: All the solenoid valves are concentrated within a single control block and the electrical connections of the valves are also centralized into a single cable for easier connections. To achieve this, an interface distributor is provided on the central control block.

Hydraulic Oil Cylinder

Hydraulic Oil Cylinder

Further reading:

Clean the Hydraulic Oil

The hydraulic system requires that the hydraulic oil be kept clean. Cleaning the oil tank is crucial.

When replacing the hydraulic oil, the cover of the oil tank must be removed. Clean the bottom of the tank using a towel (do not use cotton yarn) and then wash it with cleaning coal oil gasoline.

Due to the limited reach of the arm to the end of the tank, a towel can be wrapped around a bamboo or stick to clean the corners. The leaking plug or brake valve should be loosened to allow the dirty oil to drain.

Use a cleaning towel to dry the sides and bottom of the tank until it is clean. If necessary, use a dough ball to pick up dirt at the welding seams or hard-to-reach areas and then put the cover back on.

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 represents the average viscosity value at a temperature of 40°C. If the working pressure and temperature of the hydraulic system are higher and the working speeds are slower, a higher-marked hydraulic oil should be used.

It is recommended to use antiwear hydraulic oil ISO VG46# (with an average viscosity of 46mm2/s at 40°C). If the machine operates at temperatures below 5°C for an extended period, hydraulic oil ISO VG32# can be used.

It is not recommended to use the machine at very low temperatures (below -5°C). If this does occur, the machine should be allowed to idle for a while. If needed, an oil heater can be installed in the circuit.

Under normal working conditions, the oil temperature should not exceed 70°C. In special conditions, an oil cooler can be installed as necessary.

Fill the oil

The hydraulic oil used must be clean. To fill the oil, unscrew the nut of the air filter and fill through the filter. If using filling equipment with a filter, the cover of the oil tank can be opened and the oil can be filled directly.

Observe the oil gauge and fill the oil to 80-90% of the interspaces when the ram stops at the top dead spot.

To ensure proper functioning, the machine should be run idle first, then at maximum stroke to eliminate 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 an important component of the press brake machine.

Press Brake Seal Ring

Further reading:

Press brake weight

Press Brake Weight

The weight of the press brake machine can range from 5T to 300T, which largely depends on the size of the machine. For example, an 80T/2000mm press brake weighs approximately 6T, while a 2000T x 12000mm press brake weighs over 300T.

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