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.
Bottom Bending
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.

1. Punch and die is the important part for bending process, we need to choose the right punch and die for our products before running the machine.
2. Because the die v opening is corresponding to the bending sheet thickness, we need to choose the right opening for the bending job.
3. Because this is hydraulic press brake machine, we need to prepare the hydraulic oil firstly. The oil type is #46 anti-wear hydraulic oil and we need to fill the tank until it is full.
4. We need to prepare the necessary cable according to the machine power in advance, when we get the cable, one end will be connected to the power, another end will be connected to the machine electric cabinet.
5. After the connection of the cable, we will start the machine power and pump and check the motor rotating direction, if the direction is anticlockwise, we need to exchange the cable each line and try again until the rotating direction is clockwise.
6. When the machine is running, we need to program on the controller according to the product that we will bend step by step, we can also operate in manual mode or auto mode according to our bending purpose.
7. After the programming, we will put the metal sheet on the bottom die and start the bending work step by step and finish the product finally.

Structure
The design principle for both machines is different, it results in the different synchronous structures on both sides of the ram.
Accuracy
The ram parallelism will affect the workpiece accuracy. The NC Press brake synchronization is kept mechanically and it has no real time feedback for the error, what is more, it can not adjust by itself and will cause the low bending accuracy.
Working speed
For the press brake, we are always talking about three speeds: Down speed, working speed and return speed.
Mechanic rigidity
Because of its design, NC press brake can not bend by partial load. If it is working like this for long time, the torsion-bar will deform easily.
Crowning system
For most NC press brakes, it will not come with the crowning system as standard. The operator needs to adjust the bending angle manually before bending the official product. It will take a long time and waste material; it will also be difficult to make the product in a very precise way.

Bending machines are very useful in the industries as they create sheets of metal using some mechanical brakes. Different types of bending machine come in the market according to the sheet type industries required. It is very important to have a proper type of machine for bending as it increases the productivity of the sheet.
Plate rolling machine is a machine which is finding an important role in the industry and cab be defined as a plate rolling machine which gives round or cone shape to the sheet of different metals. Sometimes it is called as roll bending machine or roller machine.