Electric Pipe Bender
Figure 1: An electric pipe bending kit. This specific bender can bend copper pipe up to 25 mm outside diameter.
Electric pipe benders offer fast and consistent pipe bending results. Whether using a cordless pipe bender or a CNC bending machine, a user can program the device to make an exact bend without requiring many measurements. This bend can be efficiently repeated as many times as necessary, making electric pipe benders ideal for industrial mass production. This article reviews various electric bending machines and discusses their operation and applications. To learn more about pipe bending, read our pipe bender overview article.
Table of contents
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Electric pipe bender types
Electric pipe benders range from devices that fit on a workbench to machines that take up a lot of space in a factory. This section covers the following electric pipe benders, from smallest to largest:
- Cordless pipe bender
- Electric conduit bender
- 3-roller pipe bending machine
- Rotary-draw bending machine
- CNC bending machine
- Induction bender
Cordless pipe bender
Cordless pipe benders are a relatively new addition to workshops that have enhanced the ability of DIY users and small businesses to improve their work. These pipe benders have a battery that supplies power to the machine. Most cordless pipe benders are suitable for bending soft metal pipes like copper. Still, some can bend stainless steel of smaller diameters. Check with the bender’s manufacturer to determine recommended pipe materials and sizes to bend.
Cordless pipe benders do not take up a lot of space. They are small enough to sit on a workbench. They can operate in a vertical or horizontal position depending on space requirements. Also, many cordless pipe benders can attach to a tripod to improve positioning on the floor.
Cordless pipe benders use a rotating bend die (Figure 2 labeled A) and a clamp die (Figure 2 labeled B) to bend a pipe. The bend die controls the bend's inside radius, and all of the bending happens at the clamp die, which presses the pipe against the bend die.
Figure 2: A cordless pipe bender bending copper pipe: clamp (A), bend die (B), and clamp die (C) that holds the pipe to the bend die.
A cordless pipe bender operates following these steps:
- Set the angle that the pipe will be bent to, for example, a 90° bend. Many cordless pipe benders have a dial that turns to set this angle.
- Install the correct bend and clamp dies onto the bender based on the diameter of the pipe that will be bent.
- Insert the pipe between the bend and clamp dies at the point that the bend will begin. A smaller clamp (Figure 2 labeled C) holds the pipe to the bend die. Align that point with the 0 on the face of the bend die.
- Pull the trigger to operate the pipe bender.
- The bending die rotates to move the pipe past the clamp die and automatically stops after the pre-programmed bend is achieved.
- Switch the cordless pipe bender to reverse and reverse the bend die to its initial position to remove the bent pipe.
Electric conduit bender
Figure 3: An electric conduit bender with multiple dies.
Conduit is metal tubing that protects wires and cables from damage. An electric conduit bender bends conduit much faster than a manual conduit bender. As seen in Figure 3, a conduit bender bends conduit around a die (also called a shoe). Some electric conduit benders have one die that can fit multiple types of conduit and tube diameters (typically ¼ inch to 2 inches). Others use multiple dies that swap out to allow the bending of a specific conduit type.
Depending on the specific machine, an electronic conduit bender is either digitally or manually pre-set to bend the conduit to a specific angle. Then, the conduit is placed in the appropriate die, depending on the conduit’s diameter, and clamped in place with a hook and rollers. When the die rotates, the conduit goes with it and bends at the rollers. The electric conduit bender stops automatically after bending the conduit to the pre-set angle. To remove the conduit, reverse the direction of the die’s rotation until the conduit can be pulled out of the die or falls out.
Although there are several types of conduit, electric conduit benders are typically suitable for bending three types: RMC, EMT, and IMC.
- RMC (rigid metal conduit): RMC conduit is the heaviest and has the thickest walls of the various types of conduit. The walls range in thickness from 2.6 - 6.8 mm, correlating to the outside diameter of the tube. This conduit is typically constructed from coated steel, stainless steel, or aluminum. RMC conduit is threaded on both ends to make connections easily.
- EMT (electrical metallic tubing): EMT conduit is the lightest in this list and is never threaded. This conduit is galvanized on the outside and coated on the inside for corrosion resistance.
- IMC (intermediate metal conduit): IMC conduit weighs about 33% less than RMC conduit and can be, but is not always, threaded. Like EMT conduit, IMC conduit is galvanized on the outside and coated inside for corrosion resistance.
3-roller pipe bender
As seen in Figure 4, a 3-roller pipe bender has two lower dies and one upper die. The lower dies are stationary, and the upper die can move up and down. These electric benders are suitable for bending round and square pipes, channel and corner bars, and square and round bars.
Figure 4: A 3-roller pipe bender bending a steel square tube.
These electric benders work by placing one end of the pipe onto the two lower rollers and lowering the upper roller to apply a small amount of pressure on the pipe. Then, the pipe runs through the rollers. When the other end of the pipe reaches the rollers, the upper roller goes down further to apply more pressure. Then, the process repeats in the opposite direction. This back-and-forth process repeats until achieving the desired bend.
3-roller pipe benders are best for making bends with a large radius. They work more slowly than other pipe benders but can make full-circle bends to produce things like pipe coils.
Rotary-draw bending machine
Rotary-draw bending machines bend pipes using a clamp die (Figure 5 labeled A), a bend die (Figure 5 labeled B), and a pressure die (Figure 5 labeled C). The bend die controls the inside radius of the bend. The pressure die ensures that the pipe follows the contours of the bend die. Finally, the clamp die prevents the tube from slipping off the bend die. All the bending occurs at the clamp die as it moves around the die, or the die rotates past it, depending on whether it is rotary or stationary.
Figure 5: Rotary-draw bending machine with components: clamp die (A), bend die (B), and pressure die (C).
Rotary-draw benders can make single bends in short lengths of pipe. However, their optimal use is for creating multiple bends on a long length of pipe. This is achievable using an index table or a fully-automated CNC (computer numerically controlled) bending machine controlled by a servo motor.
- Index table: The pipe opposite the bent end inserts into a clamp that holds the pipe in a horizontal position. A user can push the clamp towards the bend die and rotate it to control which part of the pipe is bent and which plane it is bent towards.
- CNC bending machine: A fully-automated CNC bending machine operates similarly to an index table. However, a user programs the bends into a computer that controls the table. Therefore, a user does not need to push the pipe towards the bend die nor control its orientation. Once a bend program is in the computer, it is usable again at any time. So a user can make a specifically shaped pipe and return to the machine months later to easily recreate the exact same pipe. Also, the computer software can simulate the bend before the machine operates, so before running the program, the user will know if there will be any errors or interruptions in the bend.
Induction bender
As seen in Figure 6, an induction pipe bender uses a heated coil to heat up the pipe for bending. This is necessary with large pipes that have industrial applications.
One pipe end is held by a clamp die, which connects to a central point at an adjustable distance. Adjusting the distance of the clamp die from the central point controls the radius of the bend.
Figure 6: Induction pipe bender.
The bend point of the pipe is heated and then slowly pushed forward (0.4 - 1 mm / minute). Although a slow process, this is the most efficient way to bend pipes this large. Pipes bent by induction bending are typically for sewer systems and other industrial applications.
Electric pipe bender applications
The following table summarizes the common applications for the electric benders discussed in the previous section.
Electric bender | Applications |
Cordless pipe bender | Bend copper pipe up to 35 mm diameter at high precision. Stainless steel pipe at smaller diameters (max 28 mm) may be bendable. Check with the bender’s manufacturer first. |
Electric conduit bender | Bend RMC (rigid metal conduit), EMT (electric metallic tubing), and IMC (intermediate metal conduit) much faster than with a manual conduit bender. |
3-roller bending machine | Make large radius bends in pipe. |
Rotary-draw bending machine | Quickly and accurately make one or multiple bends in a long pipe. Make handrails, roll cages, frames, and more. |
CNC bending machine | Same as the rotary-draw except fully automatic. Use a computer to design and simulate the bends before running the machine. Save the design for future duplicate bending. |
Induction bending machine | Bend very large pipes used in industrial and sewer applications. |
Electric pipe bender pros & cons
Electric pipe benders have the following advantages and disadvantages.
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Advantages
- Speed: Electric pipe benders bend pipes in a fraction of the time that other pipe benders require.
- Accuracy: Pre-program an electric pipe bender to bend a pipe to an exact degree without the need to measure the bend angle after bending.
- Finish: The design of an electric pipe bender is specific to ensure that the finished bend does not have wrinkles or cracks. The appearance of either may mean misuse of the bender.
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Disadvantages
- Cost: Electric pipe benders cost significantly more than their manual and hydraulic counterparts.
- Space: Besides the cordless pipe bender and the electric conduit bender, electric pipe benders take up a great deal of space.
- Power: Besides the cordless pipe bender, electric pipe benders require an electricity source to operate.
Read our manual and hydraulic pipe bender articles for more information on the working of manual and hydraulic pipe benders.
FAQs
What is an electric pipe bender?
Electric pipe benders have a motor that powers the machine to bend soft and hard metal pipes much more efficiently than manual pipe benders.
Do electric pipe benders crack pipes?
When used correctly, electric pipe benders provide an uncracked and unwrinkled pipe finish.