Introduction – Press Brake
It is a kind of bending machine used for bending sheet metal into a predetermined shape. The bending depends upon the shape of the punch and the die. These are being widely used in metallurgy, aircraft and ship building, production of container and many other metal products.
Working principle of Press Brake
The metal sheet to be bended is placed between the punch and the die. The punch and die are placed in such a way that they are aligned in the same vertical axis and the shape of the punch matches that of the die. The metal sheet is clamped at both ends to prevent it from slipping during the bending process. After fixing the metal sheet, pressure is exerted on the punch which bends the metal sheet or plate against the die. The force applied is measured in tons and the capacity of a machine is measured in terms of tonnage. Depending on the means of application of pressure, they are classified as
Mechanical press brake
Hydraulic press brake
Pneumatic press brake
Press Brake set up
It set up refers to the work carried out by the operator to change the settings of the device according to the job. Every part will not be of the same size and shape. When a new part is to be pressed, some changes must be made in the device to get the shape of the metal sheet or plate as per the design. This set up procedure must be done very carefully because it directly affects the quality of the product. The operator must not take much time in setting up the machine as this may affect the production.
Key to set up Mechanical Press Brake
The key points in setting up it are listed below
· The operator must go through the drawing completely and know the type of material, the dimensions, blank size and the angle required.
· The type of tool should be selected depending upon the dimensions (internal radius in particular). For example, if the inside radius is less than the thickness of the material, bottom tooling can be used.
· The pressure or force required for the particular job must be determined.
· The position of the tool on the bed is selected based upon the tonnage. If maximum tonnage of the machine is to be used, then the tool must be positioned at the centre. If it is less, then the position of the tool can be offset.
·The selected tool must be installed at the determined position. The tool installation is the most time consuming procedure.
·While installing the tool, a safety tag must be used while placing the punch over the die.
·The die and punch must be aligned correctly and the distance between them must be set to get the exact slide length.
·The pressure or force to be exerted must be set by trial and error method to get the exact pressure required for the job.
·A test bend must be made on waste material to check the settings. If the settings are correct, the production can be started immediately.
Key to set up Hydraulic Press Brake
It is similar to that of the mechanical regarding the selection and position of tooling. Some additional points to be taken into consideration while setting up it are listed below
· The hydraulic oil must be clean and the level of the reservoir in the oil must be checked.
·The tool which is selected must be installed as per the manufacturer’s instruction.
·The distance piece must be set to compensate for the difference in penetration between punch and die.
·The slide length of the punch should be set using the controls.
·A test bend is carried out and if not satisfactory necessary changes must be made in the device.
·Most of the hydraulic devices are electronic controlled and so the operator must be familiar with the controls used for the set up of the machine.
Note: Even if the set up is perfect, the production won’t be efficient if the tool is worn out. Worn out tool must be sent to the manufacturer for re-conditioning.
Industrial Press brake are used in many industries and they come in various sizes and types for specific jobs. With the development of automation engineering, CNC Brake press have been developed which are computer controlled and the set up of the equipment can be done in a short period of time. The accuracy of the bend depends upon the set up of the equipment; so much care must be taken while setting up the device. Even if it takes a little longer to set up the equipment, the production should not be started until the operator is confident about the set up of the machine. Click Here to get more information on Press Brakes.