We are planning to make publish on lapiegatrice.it about theory press brakes in IT and DE languages. We would like to present this article also in English, probably will be helpful for somebody. This article was already published on our website about the tooling, now we are making it better and more detailed.
Press brake is the main industrial machine to perform the technological operations as plate and sheet metal bending. Today, in sheet metal industry the stand-alone press brake is the general unit for bending of pre-fabricated parts (after cut or punching) to make the shape of the final product. If we are talking about the typical sheet metal workshop before press brake there are cutting operations (cutting with laser, waterjet or plasma cutting machine or punching with punching press) and after are operations to finalize the final product as welding, painting and assembly operations.
Press brake machine is known in industry more than 70 years and press brake bending technology in general is the same with the new achievements of precision, quality and control.
In the market usually the construction of press brake is known as C-frame construction which could be explained as following: 2 shoulder side plates with the table (the term “bed” as also used) between them, the beam or traverse as the moveable unit to add the force and to perform the bend, power unit which is responsible to initiate the force, press brake tools installed according to the bending task, backgauge for part positioning operations and the units for control of movements and positioning.
The functionality of press brake is equal to the press but the construction is made to perform the deformation of sheet metal for bigger length and it means that forced and controlled movement works on sides of the beam.
Wikipedia and other sources provide a lot of general mixed information about press brakes but we would like to make more theoretical article about types according to the way of working and possibilities. Anyway our classification is not official and could be used widely by different manufacturers to provide their own specifications.
According to the layout and press brake dimensions press brakes could be:
- Compact (small machines with the length of bending up to 1200–1500 mm) usually for small parts, low tonnage and small dimensions to install in workshop. We would like to note that small machines (and on the market are available constructions even with 300–500 length) could have the forced movement not on sides and directly at center. The small length of bending allows to not have any deflection of beam on sides.
- Typical standard machines from 1500 up to 6000 mm with different tonnage.
- Big machines usually with high tonnage and big length applications from 6000 till 12 meters or more.
According to the power unit to obtain the force and the power the beam of the press brake:
- Manual handled (table and console machines with the hand levers to obtain the force)
- Mechanical with the flywheel (old and rare constructions)
- Pneumatic (also old and rare constructions which were used in years 70–80s)
- Hydraulic (powered by the hydraulic cylinders — the general concept of press brake used worldwide today)
- Servo-hydraulic or Hybrid (powered by hydraulic system and servodrive)
- Electric (modern technology to obtain the force and movements with the servodrive without the usage of hydraulics)
In addition it is necessary to tell that this terminology used to identify only the power unit for force and beam movement but not the movement of the backgauge which is usually manual or servo-electric in all the ways.
According to the force press brakes could be:
- Low tonnage (usually up to 30–40 tons)
- Medium tonnage (50–120 tons)
- High tonnage (120–320 tons or more)
- Heavy tonnage (more than 320 tons up to any values. On the market there are supplies of machines up to 2200 tons in one machine or more)
According to the stroke press brakes could be:
- Upstroke (the stroke is performed by the beam on top side — the standard concept for all main machines worldwide, the table is idle and non-moveable)
- Downstroke (the non-moveable top side of the machine and the table is moving towards to the upper beam. This configuration is very rare, we know only one low-tonnage machines active manufacturer with this concept)
According to the clamping system press brakes / system of press brake tools could be (this classification means that the clamping system is pre-installed on the factory and could not be changed easily by the user itself):
- Press brakes with Promecam — Euro system (all manufacturers from Europe, mainly Asia, North and South America)
- Press brakes with American style system (the main system for North America)
- Press brakes with Trumpf-WILA or LVD similar system (with safety- or quick- clicks and buttons)
- Press brakes with LVD- old system; Beyeler-Bystronic , Colgar, EHT, Colly-Ajial, Durmazlar, country-specified machines etc. (clamping systems specified and used by the specific manufacturers)
According to the construction press brakes could be:
- Standard machine
- Tandem (two standard or non-standard machines installed together with the synchronization of the movement to achieve the total bending length for 2 machines)
- Tridem (as tandem but 3 machines installed together)
According to the opening press brakes could be:
- Standard as the standard opening / daylight planned for manufacturer as standard construction
- Extended opening for bigger daylight and extended stroke for deep applications.
According to the control and possibilities the press brakes could be:
- Manual completely with handy or hand wheel regulations and adjustments. The bending and movement usually performed by hand lever. Backgauge is manual or just stopper, no any automatic movements
- Semi-automatic as NC or simple controller machines. For example the movement of X-axis could be controlled in display but only this movement, simple adjustments for press brake stroke and finally only beam approach and the backgauge approach movements for control
- CNC controlled machines with installed computer numerical control and possibility of interfaces for programming, program storages, various cycles, control of more than 2 axis and auxiliary units control, simulation possibilities etc.
According to the automation press brakes could be:
- Stand-alone machine as one single unit
- Standard machine with the partial automation — for example equipment of sheet followers for big or heavy parts
- Robotic cell which means to replace the operator with the robot to load and unload parts and move according to the necessary positioning
- Complex automation systems with robots or other devices to perform not only the movements of part but also to change the press brake in automatic mode if necessary and connected with automatic tooling storages systems as well as automatic transfer of pieces to other machine tools (punching machine, laser cutting, pressing etc.)
- Automatic systems with gantry-type systems (the same as robot but the other concept of automation)
According to the safety rules press brakes could be:
- CE-certified with laser or light guards
- CE-certified with low working speed without the additional safety devices
- Non CE-certified
This post is also published on @Medium
