Press brake

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A press brake bending a sheet of steel

A press brake is a type of brake, a machine used for bending sheet metal and metal plate. [1] It forms predetermined bends by clamping the workpiece between a matching top tool and bottom die. [2]

Contents

Bending process Bystronic Bending.jpg
Bending process
A high-tonnage hydraulic press brake High-tonnage press brake.jpg
A high-tonnage hydraulic press brake
Liwei CNC 2000T 12M Heavy Duty model Liwei 2000 Ton Press Brake 12 Meter.jpg
Liwei CNC 2000T 12M Heavy Duty model

Typically, two C-frames form the sides of the press brake, connected to a table at the bottom and on a movable beam at the top. The bottom tool is mounted on the table, with the top tool mounted on the upper beam.

Types

A brake can be described by basic parameters, such as the force or tonnage and the working length. [1] Additional parameters include the stroke length, the distance between the frame uprights or side housings, distance to the back gauge, and work height. The upper beam usually operates at a speed ranging from 1 to 15 mm/s.

There are several types of press brakes including nut-stop hydraulic, synchro hydraulic, electric and hybrid.

Hydraulic presses operate by means of two synchronized hydraulic cylinders on the C-frames moving the upper beam. [3] Servo-electric brakes use a servo-motor to drive a ballscrew or belt drive to exert tonnage on the ram.

Historically, a mechanical press entailed with energy that was added to a flywheel with an electric motor. A clutch engages the flywheel to power a crank mechanism that moves the ram vertically. Accuracy and speed are two advantages of the mechanical press. [3]

Until the 1950s, mechanical brakes dominated the world market. The advent of better hydraulics and computer controls have led to hydraulic machines being the most popular.

Today's press brakes are controlled by two types of controls, NC (Numeric Controlled) or CNC (Computer Numeric Controlled). NC is a basic controller where the CNC is the high-end controller. Although the initial outlay might be more than with an NC , a CNC controller can be more effective, keeping cost down in the long run.

Pneumatic and servo-electric machines are typically used in lower tonnage applications. Hydraulic brakes produce accurate, high-quality products; are reliable; use little energy; and are safer because, unlike flywheel-driven presses, the motion of the ram can be easily stopped at any time in response to a safety device, e.g. a light curtain or other presence sensing device.

Back gauge

Biegeanimation 2D.gif

Recent improvements are mainly in the control and a device called a back gauge. A back gauge is a device that can be used to accurately position a piece of metal so that the brake puts the bend in the correct place. Furthermore, the back gauge can be programmed to move between bends to repeatedly make complex parts. The animation to the right shows the operation of the back gauge, setting the distance from the edge of the material or previous bend to the center of the die.

Press brakes often include multi-axis computer-controlled back gauges. They allow operators to position material correctly and sequence the bends step-by-step until completed. Optical sensors allow operators to make adjustments during the bending process. These sensors send real-time data about the bending angle in the bend cycle to machine controls that adjust process parameters.

Dies

Press brakes can be used for many different forming jobs with the right die design. Types of dies include: [3]

See also

Related Research Articles

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<span class="mw-page-title-main">Machine press</span> Machine tool that changes the shape of a work piece by the application of pressure

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<span class="mw-page-title-main">Numerical control</span> Computer control of machine tools

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<span class="mw-page-title-main">Sheet metal</span> Metal formed into thin, flat pieces

Sheet metal is metal formed into thin, flat pieces, usually by an industrial process.

<span class="mw-page-title-main">Hydroforming</span> Method of shaping metal through pressurized water

Hydroforming is a means of shaping ductile metals such as aluminium, brass, low alloy steel, and stainless steel into lightweight, structurally stiff and strong pieces. One of the largest applications of cost-effective hydroforming is the automotive industry, which makes use of the complex shapes made possible by hydroforming to produce stronger, lighter, and more rigid unibody structures for vehicles. This technique is particularly popular with the high-end sports car industry and is also frequently employed in the shaping of aluminium tubes for bicycle frames.

<span class="mw-page-title-main">Punch press</span>

A punch press is a type of machine press used to cut holes in material. It can be small and manually operated and hold one simple die set, or be very large, CNC operated, with a multi-station turret and hold a much larger and complex die set.

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<span class="mw-page-title-main">Stamping press</span>

A stamping press is a metalworking machine tool used to shape or cut metal by deforming it with a die. A stamping press uses precision-made male and female dies to shape the final product. It is a modern-day counterpart to the hammer and anvil.

<span class="mw-page-title-main">Bending (metalworking)</span> Metalworking to produce a V-, U- or channel shape

Bending is a manufacturing process that produces a V-shape, U-shape, or channel shape along a straight axis in ductile materials, most commonly sheet metal. Commonly used equipment include box and pan brakes, brake presses, and other specialized machine presses. Typical products that are made like this are boxes such as electrical enclosures and rectangular ductwork.

<span class="mw-page-title-main">Deep drawing</span> Metalworking process

Deep drawing is a sheet metal forming process in which a sheet metal blank is radially drawn into a forming die by the mechanical action of a punch. It is thus a shape transformation process with material retention. The process is considered "deep" drawing when the depth of the drawn part exceeds its diameter. This is achieved by redrawing the part through a series of dies.

Notching is a metal-cutting process used on sheet-metal or thin bar-stock, sometimes on angle sections or tube. A shearing or punching process is used in a press, so as to cut vertically down and perpendicular to the surface, working from the edge of a work-piece. Sometimes the goal is merely the notch itself, but usually this is a precursor to some other process: such as bending a corner in sheet or joining two tubes at a tee joint, notching one to fit closely to the other.

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Roll forming, also spelled roll-forming or rollforming, is a type of rolling involving the continuous bending of a long strip of sheet metal into a desired cross-section. The strip passes through sets of rolls mounted on consecutive stands, each set performing only an incremental part of the bend, until the desired cross-section (profile) is obtained. Roll forming is ideal for producing constant-profile parts with long lengths and in large quantities.

Press tools are commonly used in hydraulic, pneumatic, and mechanical presses to produce the sheet metal components in large volumes. Generally press tools are categorized by the types of operation performed using the tool, such as blanking, piercing, bending, forming, forging, trimming etc. The press tool will also be specified as a blanking tool, piercing tool, bending tool etc.

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A bending machine is a forming machine tool. Its purpose is to assemble a bend on a workpiece. A bend is manufactured by using a bending tool during a linear or rotating move. The detailed classification can be done with the help of the kinematics.

<span class="mw-page-title-main">Turret punch</span>


A turret punch or turret press is a type of punch press used for metal forming by punching.

In machining, an automatic tool changer (ATC) is used in computerized numerical control (CNC) machine tools to improve the production and tool carrying capacity of the machine. ATCs change tools rapidly, reducing non-productive time. They are generally used to improve the capacity of the machines to work with a number of tools. They are also used to change worn out or broken tools. They are one more step towards complete automation.

References

  1. 1 2 Fournier, Ron; Fournier, Sue (1989), Sheet metal handbook, HPBooks, p. 37, ISBN   978-0-89586-757-5
  2. Parker, Dana T. Building Victory: Aircraft Manufacturing in the Los Angeles Area in World War II, p. 29, 83, Cypress, CA, 2013. ISBN 978-0-9897906- 0-4.
  3. 1 2 3 Tool and Manufacturing Engineers Handbook (TMEH), Volume 2, Forming. Society of Manufacturing Engineers, 1984.[ page needed ]

Further reading