Press Brakes

Press brakes for sheet metal work

The press brake, also known as a bending press or die bending machine, is the core machine for bending sheet metal. A punch presses the workpiece into a die and forms it into a defined edge. The depth of the stroke sets the bending angle, from a simple fold through to a multi-bend profile. That is how enclosures, housings, panels and structural parts are made for metal fabrication, vehicle building and general sheet metal work. KNUTH supplies press brakes in conventional and CNC versions and across several machine sizes.

How a press brake works: punch and die

In bending, the punch lowers onto the sheet, which rests on the die. The usual method is air bending: the punch enters only far enough to form the required angle, without pressing the sheet fully into the die. Working through the stroke depth, the machine sets any obtuse angle. Two things decide the accuracy:

• Crowning: under load the press beam deflects slightly. Crowning compensates for that deflection so the bending angle stays even over the full length.
• Angle measurement: CNC press brakes measure and correct the angle during the bend, which is how they reach high repeatability.

The bending length you can reach and the press force you need depend on sheet thickness and material. The values for the machines currently available are shown in the product cards above.

Conventional or CNC press brake: which one fits

KNUTH press brakes are hydraulic. The difference lies in the control:

• Conventional press brake: the stop and bending depth are set by hand. This build is robust, easy to operate and economical for simple edges and small batches.
• CNC press brake: a control system handles the back gauge, press force and bending angle by programme. That shortens set-up time, secures repeatability and suits complex parts and larger quantities.

As a rule of thumb, simple and repeating bends point to the conventional machine, while complex profiles and high volumes point to the CNC press brake.

Technical features and machine sizes

Two figures drive the choice. The bending length has to match the longest workpiece edge, and the press force has to match the combination of sheet thickness and material. As a guide, thicker sheet and longer edges call for more press force. KNUTH supplies press brakes from the compact size for the workshop through to the long, heavy CNC machine for structural fabrication. Further features include the programmable back gauge for accurate positioning, crowning for even angles and safety equipment to protect the operator. The exact values for each series are given in the product cards above.

Tooling and dies

The result from a press brake stands or falls with the tooling. Punch and die decide which angles and radii are possible:

• Punches (upper tools) in various tip radii and forms, including tooling for tight and multi-bend profiles
• Dies with different V-openings for different sheet thicknesses
• Quick-clamping systems for a fast tool change

Which tooling you need depends on your sheet and your bends. Matching tooling and accessories can be quoted together with the machine.

Applications and industries

The press brake is at work right across sheet metal fabrication. Typical workpieces and industries are:

• Enclosures, control cabinets and panelling in machinery and plant building
• Profiles, angles and folded parts in metal and structural steel work
• Components for vehicle, ventilation and facade construction

For cutting blanks before bending, KNUTH supplies guillotine shears, and for bending without a tool change, folding machines.

Why KNUTH

KNUTH is an established supplier of machine tools with a coordinated range for sheet metal work. Each machine is given a documented inspection and shipped CE-compliant. You get personal advice on the right bending length, press force and equipment instead of a bare catalogue choice, along with tooling and accessories from a single source. Around 1,000 machines are ready to ship from the European central warehouse in Germany. For an overview of the full sheet metal range, see the sheet metal processing category.

Service, spare parts and availability

Service runs through our own service network, with our own service engineers looking after the machines in the field. Commissioning and operator instruction for your team are available as a separate service. A ten year spare parts supply commitment applies. For help sizing your press brake, choosing tooling or checking availability, reach us through the contact page.

Further Machine Categories at a Glance

Here is an overview of our machine range. Select a category to learn more about individual machines and their technical data.