Bending Machine: Comprehensive Guide for Beginners

In today’s manufacturing landscape, bending machines are indispensable tools, shaping raw materials into precise forms with unmatched efficiency. From crafting angular designs into sheet metal to curving robust steel tubes, these machines are the backbone of countless industries, including automotive, construction, HVAC and more.

However, finding the right bending for your business can be a challenging process.
This article simplifies the basics of metal bending machines and compares their various types, applications, and benefits.

What are Bending Machines?

Bending machines are metal processing tools that bend, shape, and curve parts at various angles. The bending process is a cold working technique that gently stretches the metal to the desired angle. Occasionally, some machine oil or lubricant is required to help reduce the resistance between the workpiece and the die press.

The key to a high-quality bender is the even distribution of pressure along the surface of the metal workpiece. Equal and consistent force reduces the risk of metal fatigue and accidental fracture.
Benders have near-universal metal compatibility. They can bend everything from soft metals like copper and aluminum to tough ones like stainless steel and titanium.

How Does a Bending Machine Work?

The machine type primarily determines the basic working principle of a bending machine. Press brake-type bending machines use a punch-and-die approach to shape sheet metal. Contrarily, a pipe-bending uses a set of two to three spinning rollers that stretch and bend the pipe.

Later, as we get into the details of the different benders, we will see that the general principle remains the same. To initiate the bend, the metal workpiece needs two controlled opposing forces at a concentrated point.

We discuss the various metals being processed in more detail later in the article.

Different Types of Bending Machines

Whether it’s small pipes, large tubes, rebar, thick metal plates, or regular sheet metal, a bending machine is available for all application

Each bending machine has specific functions that cater to the various metal fabrication processes.

Pipe Bending Machine (Tube Bending)

A pipe bender is designed to bend cylindrical shapes so that the pipe’s internal diameter remains consistent throughout its entire length. Although such machinery is commonly called a pipe bending machine, it can bend other tube shapes like rectangular or square tubes, solid rods, or metal channels.

Parameters

Pipe bender parameters vary from machine to machine. Most industrial machines have the following parameters.

Outer Diameter Range – 0.5 inches to 72 inches
Bending Radius – 1.5D – 20D (D=Diameter)
Max Bending Angle – 270°
MAX Wall Thickness – 5 inches
Types of Pipe Bending Machines
Pipe bending machine work can be categorized into a few types based on manual or automatic configurations and their different feature sets. There are four basic types of pipe-bending machines.
Rotary Draw Bending Machine (Stretch Bending)
Compression Bending Machine
Ram Bending Machine
Roller Bending Machine

Process

A rotary draw pipe bender machine clamps the metal tube along a circular bending die. A lever pulls the tube along the die, curving it in the process. This technique best suits small to medium-diameter pipes, tubes, and rods.

A compression pipe bender uses compressive force to shape the metal tube. It has two sideways pressure pistons that press the front and back of the tube against a circular bending die. Compression bending is preferred for its ability to bend large pipes with ease.

A ram pipe bender is the opposite of compression bending. It uses a ram to apply pressure to the center of the bend point instead of applying force to the pipe’s surrounding area. This technique can bend pipes at sharper angles.

The roller pipe bender tool involves three or more rollers that spin in opposite directions. As the metal pipes move through the machine, the rollers slowly bend them to one side. The distance between the rollers helps determine the angle of the bend. Repeated passes through the machine are recommended for the highest quality bends, with each pass increasing the bending angle.

Plate Rolling Machine

A plate roll bender is an industrial tool designed to curve large metal plates into a cylindrical or semi-cylindrical path. Even entry-level plate rollers are usually the size of a truck and are either fully or semi-automatic.
A standard industrial plate rolling machine can cold roll up to 3-inch thick metal plates. The same machine can even bend 4-inch thick plates using hot rolling.

Parameters

Here are some common operation parameters of plate rolling machines.

Workpiece length – 12ft. 144 inches.
Workpiece Width – As Per Roller Length
Workpiece Thickness – 3 inches (Cold Rolling) or 4 inches (Hot Rolling)
Maximum Rolling Diameter – 12 ft.

Process

The general design of a plate rolling machine remains consistent across various models. It uses a three-roller system arranged in a pyramid shape. The top roller applies downward force, and the bottom two rollers apply counter-reaction, keeping the metal plate securely clamped in the middle.

Powerful motor control systems monitor and adjust the distance between the top and bottom rollers. Like pipe bending machines, multiple passes through the machine are required for sharper bends.

Applications

Petrochemical and Oil & Gas – Containment Tanks
Aerospace and Aviation – Rocket Exterior
Automotive and Transportation – Tank Truck
Mining and Heavy Equipment – Underwater Piping
Shipbuilding and Marine Industry
Construction and Architecture

Sheet Metal Press Brake

A sheet metal bender is a powerful tool for shaping flat metal sheets into complex shapes and structures. These bending tools can bend, curve, and fold metals at various angles for a sharp, angular, or rounded finish.

Sheet metal bending is always used in conjunction with a metal cutting technique. For example, fiber laser cutting machines are used to cut out the basic shape, and bending machines are used to shape it into a 3D design.
Sheet Metal Bending on Carbon Steel
Similar to pipe rolling, several types of sheet metal bending techniques exist.

Punch and Die Bending Process
Single Die Beading Process
Two Die Shaping Process
Roller Bending Process

Parameters

Sheet Thickness Range – 0.08 to 0.24 inches
Max Sheet Length – Machine Size Dependent
Max Sheet Width – Machine Size Dependent

Process

In punch and die sheet metal bending, the metal sheet is squished between a powerful piston and two counter supports (die) to create bends.
Single-die beading involves pushing the metal sheet into a circular cavity die, shaping the sharp edge of the metal sheet into a rounded edge.
Two-die shaping involves sandwiching a metal sheet between a positive and negative die. The upper and lower dies mirror one another and fit together perfectly when closed.
Roller bending sheet metal involves three rollers that curve metal sheets. Sheet metal rollers are smaller than plate rolling machines.

Applications

Electronic Enclosure Manufacturing
Automotive Body Panels
Metal HemmingMetal Hemming
Refrigerators
Brackets
Various Industrial Applications.
Heming is the process of reinforcing metal edges and hiding the burs.

Press Brake Machine

Press brake machines are specialized industrial metal plate and sheet fabrication tools. They utilize a punch-and-die approach to bending and have robust brakes that stop the punch from fully making contact with the die underneath.
A press brake machine can output incredible downward force, allowing for thick metal plate processing. It also supports different braking systems that have their own advantages.

Hydraulic Brakes
Electric Brakes
Hybrid Electric Brakes
Syncro Brakes
Nut-Stop Brakes
Electric brakes are the highest-performing option and are generally preferred for their near-silent operation.

Press Brake Bending Machine with Electronic Brakes

Parameters

Sheet Thickness Range – 0.24 to 0.80 inches
Max Sheet Length – Machine Size Dependent
Max Sheet Width – Machine Size Dependent

Process

A matching punch and die set is attached to the press brake machine. Bending instructions are fed to a computer system that determines the punch’s compressive force and braking point.

Press brake machines come with a diverse range of punch and die tools that determine the bend’s angle, shape, and finish.

Applications

Press brake machines are used in various industries for different metal-forming applications.

Heavy Machinery
Construction
Automotive
Ship Building
Oil and Gas
etc.

Conclusion

Metal bending tools play a big part in our modern manufacturing industries. The traditional method of hammer curving parts was time-consuming and yielded poor results. Modern bending methods, like hydraulic bending and pipe rolling, have proven themselves time and time again. Pipe bending, in particular, is a necessary element for plumbing work.