The press brake is a machine which features an upper and lower beam connected by two c-frames at either end. The beams hold tooling known as punch (upper) and dies (lower).
The tooling on the upper and lower beams will determine the type of profile to be formed by the bend. The two tools must match and be compatible with the thickness of the material being bent.
With the tooling properly installed and the press brake calibrated for the bend operation the sheet metal is placed between the punch and die. A back gauge, attached to the press brake, squares the work piece and positions it for the bend.
The tooling is closed down on the sheet metal forming it accordingly. The press brake then opens again and releases the finished piece.
This is a very simple and basic process for using a press brake. There are much more complicated processes and forming strategies which can be used depending on the desired result. Make sure safety is always at the forefront of your fabrication techniques.
Types of Press Brakes
Press brakes should always be classified first by the type of power source used to driving the acting beam. Mechanical press brakes represent the majority of older machines. These brakes are powered by a fly wheel which, when engaged by a clutch, deliver power to the acting beam. Once engaged these machines can be stopped but can’t return until they have finished their stroke. Because of this and their innate inaccuracy they are not widely used on newly manufactured press brakes. Pneumatic press brakes use compressed air as a power source. Slow cycle times, low tonnage capacity and minimal cost savings make these brakes rather rare. Hydraulic machines use hydraulic rams which allow for incredible accuracy and repeatability while delivering the important safety feature of being able to retract the brake at any time during the bend operation. While popular for a time hydraulic brakes are beginning to be replaced by servo-electric driven models. These use a variety of electro-mechanical solutions to improve the accuracy and speed of the machine while reducing cost and eliminating the maintenance associated with hydraulic machines.
The next distinguishing feature of a press brake is which beam moves during the forming process. Up acting press brakes have a fixed upper beam while the lower beam is powered and moves up to close the tooling. Down acting brakes have a fixed lower beam while the upper beam moves. While each design has some minor advantages compared to the other the majority of press brakes are down acting.