Unlike the hydramechanical press brake that converted the hydraulic energy to mechanical energy with a hydraulic motor fixed to an eccentric shaft, the modern hydraulic press brake uses a hydraulic pump and hydraulic cylinders to mover the ram. This design is far more efficient, allowing increased speed and accuracy.

The modern hydraulic press brake can be divided into two basic subgroups , up-acting and down-acting(all other types of press brakes are down-acting only.)

The French designed and were first to use, the up-acting style of press brake. In our opinion, up-acting is the best type of press brake, not only because of the ram’s guidance and arrangement of rollers, but also because of its natural antideflection characteristics. On this machine you have gravity on your side, working with you instead of against you.

For any mechanical device to have movement, it must have some clearance built in to allow the mechanism to function freely. On the press brake, an important clearance lies between the power source and the ram body. The clearance is just right when the machine is new or rebuilt. However, with age and use this clearance will increase (sometimes dramatically), causing an ever-increasing amount of play in the mechanism. When the press is a down-acting, this excess clearance, or “play” is located on the bottom when no load is present. When a load is applied, such as when a piece of material is formed, this error moves to the toe of the connection. This hurts the ram’s repeatability, often leading to vast swings in bend angle from one workpiece to the next, the up-action press brake, on the other hand, always keeps this play on the bottom, whether under pressure or not.

Down-acting hydraulic press brakes represents 90% of all press brakes in use today. Of all the down-acting press brakes, the hydraulic is, by far, the most accurate, these machines are controller by a CNC or DNC controller (computer numerical control or direct numerical control). The computers, in turn, control a proportional valve system. This system allows for ram control in the downward direction, which, in turn, gives accurate bend angle control.

The press brake machine is widely used for the steel sheet metal processing, mostly they will be used in the following fields:
Decoration industry
The CNC press brake machine will be used for bending the stainless-steel elevator, steel door and frame, steel windows and skirting line. Sometimes we will use the CNC V grooving machine after bending to get the perfect bending angles.
Electric industry
The press brake plays an important role in the production of electric cabinet. After the steel sheet cut by the shearing machine, we will use the press brake machine to bend them into different size of the cabinet by different types of the punch and die. The segmented tooling is also the necessary part during the production, especially for the left and right horns of the punch, it is vital to form the box in the final stage.
Kitchen industry
Most of the kitchen devices are made of stainless steel, we need to use the press brake to bend them into different shapes before the final product is finished. Mostly we will use the CNC Press brake with different punch and die, like gooseneck punch and 2V die by segments. We can also use this machine to make the HVAC and other related products.
Automobile and ship industry
In this field, large capacity press brake and CNC press brake will be widely used and it as higher requirement for the bending accuracy and efficiency. HARSLE is one of the press brake manufacturers in China who is capable to produce such machines and offer good service for customers from all over the world.
Aerospace industry
High precision is generally required in this industry, because the product which produced by CNC Press brake is the key part for the final product and the bending tolerance should be within the acceptable range. HARSLE has many customers in this field and they are all satisfied with our press brake.

The bending proceed is executed by the punch and die, the upper punch is installed on the ram and the bottom die is anchored on the table. When the punch moves together with the ram up and down, the sheet will be bent into different angles or shapes. There are three different types of bending methods used in forming sheet metal: coining, bottom bending, and air forming. Each has a specific purpose and application.
Coining
Coining was probably the first bending method practiced in the sheet metal trade. The process requires an amount of tonnage so great that the material being formed actually flows. This flowing goes out from the coined segment to that part of the workpiece not under pressure. If the bend radius is sharp (less than 63% of the material thickness), the punch tip can actually penetrate into or past the neutral axis of the bend. There the yield of the material is broken. With this penetration of the neutral axis by the punch tip, the springback almost disappears, and material remains permanently deformed at the point where the pressure was released.
Spodní ohýbání
There are many similarities between coining and bottom bending. With coining, however, the entire surface of the material comes into contact with the tooling, which is stamped so severely that the material actually flows, with bottom bending, on the other hand, only the radius is stamped into the material. Springback is the characteristic of most materials to try to return to the flat position after forming. The angular tooling clearance should be equal to the springback. As pressure is applied to the radius, the material passes by the required angle and up to a total equal to the required angle and the springback; then it is forced back to the required bend angle.
Air forming
Air forming is a three-point bending operation. The three points are the punch tip and both top corners of the die, Air forming uses the penetration of the punch tip into the die space as the determining factor in achieving the required bend angle. Because its tonnages are greatly reduced from those required for coining or bottoming, air forming is fast becoming the method of choice by most manufacturers. Wear and tear on the press brake and tooling is greatly reduced, leading to a marked increase in equipment longevity.
Each of there foregoing styles of metal forming has a purpose. Each is capable, within its limitations , of producing an excellent product, it takes the practiced eye of the journeyman to know why and when specific techniques should be used.

Common classifications of bending machines are as follows:

Manual bending machine
This type of bending machine has a relatively simple structure and is labor-intensive through manual operation, and is suitable for small-scale processing.

CNC ohýbací stroj
The essence of the CNC bending machine is a CNC bending machine mold for bending thin plates. The mold is composed of a bracket, a worktable and a clamping plate. Clamping of thin plates. Because the electromagnetic force clamping method is adopted, the pressing plate is made according to the specific workpiece requirements, the operation is simple, and the workpiece with the sidewall can be processed.

Hydraulic CNC bending machine
Hydraulic bending machines can be divided into torsion shaft synchronization, machine-hydraulic synchronization, and electro-hydraulic synchronization according to the different synchronization methods. Hydraulic bending machine is divided into the upper-moving type and lower-moving type according to the different movement modes.
The hydraulic bending machine is mainly used in the sheet metal industry, such as bending and forming automobiles, doors and windows, steel structures, etc.: V-grooving of metal sheets and other fields. Its structure and working characteristics are all-steel welded structure, vibration relief stress, high machine strength and good rigidity. Hydraulic upper transmission, is stable and reliable. Mechanical stop, torsion axis synchronization, high precision. The back gauge distance and the stroke of the upper slider are electrically adjusted, manually fine-tuned, and digital display.

Press brake machine is an important equipment in sheet metal processing, and its working accuracy directly affects the bending accuracy of workpieces. In the bending process of the workpiece, because the two ends of the ram are stressed mostly, the reaction force when the plate is bent leads to concave deformation of the lower surface of the ram, and the deformation of the middle part of the ram is the most, the final bent workpieces have different angles in the whole length direction. In order to eliminate the adverse effects of ram deformation, it is necessary to compensate the deflection deformation of ram. The usual Crowning Systems are hydraulic Crowning and mechanical Crowning, which make the middle part of the workbench produce upward elastic deformation to offset the deformation of the ram of Press Brake, ensure the precision of machining joint surface and improve the precision of workpiece. At present, major foreign press brake manufacturers have adopted mechanical crowning devices. Domestic manufacturers will choose the appropriate Crowning method according to the actual situation.