There are many kinds of bending machines, such as mechanical press brake, hydraulic press brake, servo-electro press brake, etc.
At present, the most widely used is the CNC press brake, which is an electro-hydraulic servo press brake.
The servo system and grating ruler of the electro-hydraulic servo press brake can control the accuracy of the machine during operation.
The CNC control system can set all bending parameters to ensure the accuracy of bending procedures.
This article will introduce the structure, operation and maintenance of the CNC press brake.
The main body of the press brake is composed of two C-shaped frames on the left and right sides.
The bottom worktable and the top beam are connected to C-shaped frames.
The ram part consists of a cross beam with upper punches and a workbench with bottom dies.
The back gauge aims to provide an accurate positioning function.
The components and operation of the press brake are basically the same. In addition to the driving source and individual parts are different more or less.
Next, this article will detail each component of the press brake.
The frame of the press brake is the basic structure supporting other parts.
The frame is a high-strength all-welded structure, which is composed of left and right side vertical
plates, the bed(worktable) and the connecting support.
Frames are usually C-shaped, but there are also square ones.
The depth of the frame, that is, the throat depth, provides enough bending space.
There are also monitoring tools on the frame to detect the springback and keep the minimum amount of springback.
The ram of the press brake can be divided into upper and lower parts.
The ram is the component of the driving mechanism for the machine to apply pressure.
The ram is made of a whole steel plate, and the piston rod connects the ram with the oil cylinders.
The ram is driven by synchronous hydraulic cylinders on both sides.
Mechanical press brake drives ram through crank mechanism and flywheel.
The grating rulers on both sides of the ram can accurately position the ram for synchronous movement.
With the help of the oil cylinder and mechanical stopper, the ram can prevent crowning.
The workbench is the base of the press brake. The tool holder of the bottom dies is installed on the workbench.
There are two modes of motion when bending. One is the downward movement of the top die. One is the upward movement of the lower die.
The beam drives the ram to exert a force downward, which is evenly distributed.
The crowning mechanism of the press brake workbench can adjust the distribution of the force accordingly.
The back gauge is a set of devices located at the rear of the press brake.
It is used to precisely position the workpiece before bending.
The back gauge of the CNC press brake is driven by different motors and moves on different axes.
The ball screw and timing belt ensure the synchronous movement of the back gauge.
The back gauge is controlled by the CNC controller and can move on 6 different axes.
The R-axis indicates upward and downward movement. The X-axis represents forward and backward movement. The Z-axis indicates left and right movement.
When the back gauge moves forward and backward, the force is limited to 150N to prevent the collision.
During bending, the workpiece is placed on the die of the workbench. Push the workpiece to fit with the stop finger. The back gauge has many stop fingers connected with the workpiece.
The press brake clamps are used to fix the toolings. Clamps are divided into upper clamps and clamps on the workbench.
During the camping process, the upper clamps can align the center automatically.
Clamps are also divided into ordinary clamps and fast tool clamps.
The fast tool clamps can quickly and conveniently replace the punches.
Punches and Dies
The toolings of the press brak are divided into the punch(top die) and die.
The die used for bending depends on the bending method, bending angle, raw material and material thickness.
During bending, the ram drives the upper die to press into the lower die, which is a bending stroke.
Punch has right angle die, acute angle die, gooseneck die, etc., and lower die has U-shaped die, V-shaped die, etc
Motor, oil pump, oil filling valve and oil cylinder are the main devices of the hydraulic system.
These devices are installed on the frame of the press brake, and there is an oil cylinder on the left and right uprights respectively.
The hydraulic pump converts mechanical energy into liquid pressure energy to drive the hydraulic system.
The pressure of the liquid can be converted into kinetic energy by the hydraulic cylinder to drive the ram.
Various control valves in the hydraulic system accurately control the oil output, pressure, etc. to control the movement of the hydraulic system.
The controller of the CNC press brake can control the bending process through programming.
The controller can accurately control the movement of different parts of the machine.
The controller can save complex bending steps for reuse.
The controller has the button version and touch screen version.
The control system provides 2D and 3D graphics programming to simulate the bending process.
Various parameters can be saved in the system.
At present, the most popular controller brands in the market include Delem, ESA, Cyblec, etc.
There are usually safety doors on both sides of the press brake.
When the safety doors are closed, the dangerous area is inaccessible on both sides
When the safety doors are opened during operation, all axes will stop moving.
More advanced protection devices are light curtain safety devices and laser protection devices.