Mandrel Bender Manufacturer in China

Many industries require smooth and wrinkle-free bends, such as automobile and motorcycle exhaust pipes, handrails, food sterilization pipes, etc., which will require inserting a mandrel inside the pipe.

HIPPO provides hydraulic mandrel benders and CNC mandrel tube benders with bending range from 6mm to 89mm,  the bending radius can be 1.5D or less. Our mandrel tube bender can perfectly bend round, square and rectangular tubes.

We can provide various mandrel, such as cylindrical mandrel, universal single, double, triple, and four ball mandrel etc., to prevent wrinkles and ovalization of your tube. Our mandrel have a long service life, it provides excellent performance, and are easy to install and replace. With more than 10 years of experience, we can help determine the mandrel form and material required for your pipe.

We can also customize mandrel pipe bender to help you deal with ultra-long pipe fittings, such as boiler U-tubes with a length of more than 10 meters.

Contact us for more information about our different models of mandrel bending machines.


Mandrel Bender FAQ Guide


1. What is a Pipe Bending Mandrel?


A mandrel is a special tooling component used to achieve perfect bends, it is designed to tackle wrinkles and collapse caused during pipe bending operations.

2. What is a Mandrel Bender?

Mandrel bender is especially used for bending tubes with a particularly smaller radius. Thin tubes are prone to damages and are wrinkled when bent, that’s why you require an exclusive technique for bending thin tubes with a thin radius.

With a mandrel bender, you can attain the most perfect and accurate results.

3. What is the Purpose of Mandrel in Tube Bending?

Mandrel bending is a technique that adds a steel rod inside the tube that will be bent. 

Mandrel offers additional support during the bending process. It allows you to bend without wrinkling, breaking, and collapse of the tube near the bending area.

4. What are Mandrels Made Of?

The mandrel material depends upon the material of the tube you want to bend.

Bending mandrels are normally made of softer aluminum alloys or steel with hard chrome plating. The softer materials contain a combination of bronze with aluminum alloy and are specially used to bend several types of tubes including stainless steel, titanium, Inconel, and many other materials.

5. When is a Mandrel Bender Necessary?

A pipe bending machine contains a complete set of dies including bending die, clamping die, pressure die, the mandrel, and wiper die. Mandrel and wiper dies are optional tooling components. 

The wall thickness and required bending radius for a pipe bending operation determine the total struggle and the type of bending machine required to make precise bends.

The smaller the radius and the thickness of a tube will be more it would be difficult to bend, and the more will be the chances of bending errors i.e. wrinkling and breaking.

Wall thickness and radius are used as special parameters to determine details for a bending process. You can use special formulas to conclude thickness by TX=t/D and bending radius by Rx=R/D. Here D is the outer radius of any tube, T is the thickness of its walls, and lastly, R is the overall bending radius.

A pipe with a total fitting of Rx> 3D and Tx> 0.04, can be used as standard molds. But for a pipe fitting with Rx <3D and Tx <0.04D, you should add mandrel and wiper dies to the tooling set to guarantee bending quality. 

6. How Many Types of Mandrels are there?

Generally, the mandrel is divided into two basic categories: one is a hard mandrel while the other is a soft mandrel.

Hard Mandrels

A hard mandrel is a cylindrical or ball-headed mandrel that has a simple shape. The material and construction method is quite convenient because of its shape. They can be used for many applications thus are preferred for many small and large-scale bending operations.

Soft Mandrels

The soft mandrels possess a rather spherical dimension, that’s the reason they are flexible and can move in various directions. Such mandrels can adapt to several deformations, so they are often particularly used for thin-walled bending or pipes with smaller bending radius.


7. How to Determine the Size of the Mandrel Ball?

It is important to determine the size of a mandrel ball, the gap between the inner tube diameter and the mandrel should be considered as an important factor. It can greatly affect the precision and quality of each bend.

If the size of a mandrel bender is too small, it can’t work properly and you can’t attain perfect bends. The tube may end up with wavy wrinkles inside the tubes and flatten the tube exterior. 

Alternatively, if the mandrel ball is larger the tube exterior won’t be smooth enough, and the tube may be strained and even break. Thus, it is important to select an ideal mandrel diameter to ensure the quality of each bend.

You can easily determine the diameter of a mandrel ball by using the following empirical formula:

d ≈ (0.94 to 0.98) D 


• “d” is the mandrel diameter.

• “D” is the tube inner diameter size.

8. How to Use the Mandrel Correctly?

The mandrel is fixed inside the tube to attain highly precise and perfect bending results. The position of a mandrel should be considered before fixing for better-bending operation, as it affects the quality of the bent pipe.

If the mandrel is positioned too far forward, the pipe might get easily stretched and the pipe gets considerably thinner.

Alternatively, if the penetration is too far back, the tube may collapse quickly, and wrinkles are formed in the interior of the tube.

You can determine the precise location for the mandrel to be placed in by combining the formulas:

e ≤ (1/4 ~ 1/2) D


• “e” represents the position for the mandrel to be placed in the pipe at beginning of any bending operation.

• “D” is the inner diameter of the pipe.

You can calculate the specific value through this formula.

9. Which of the Mandrels is Most Commonly Used?

Ball mandrels are excellently designed mandrels that flex in all directions. That is why these mandrels are most commonly used in routine mandrel bending machines. They can be adjusted and fixed properly in several types of tubing to offer accurate bending operations.

10. Does Mandrel Bent Exhaust Make a Difference?

Yes, using a mandrel bent exhaust makes quite a difference. A standard bending machine may flatten or crush an exhaust pipe while a mandrel bender retains its original shape while bending. 

This leads to the most smooth bends with no flow restrictions in the exhaust. It is also better for damping sounds; a wrinkled pipe creates more noise than a smoothly fabricated bend. That’s why mandrel-bent exhausts are preferred.

11. Can Mandrel Bend Titanium?

Titanium is a brittle metal when cold and can easily break apart at room temperature. When bent using a standard bending machine, the titanium pipes can’t hold a tight radius and may be subjected to bending deformities or even break.

That’s why they must be bent by using a mandrel bender for perfect bending results and bend quality. But it can only be bent by using a softer mandrel, as with additional pressure exertion weak titanium pipe can break.

12. What is Ball Mandrel?

A ball mandrel is a type of mandrel and a tube bending component. It can be placed in the tube to provide support during the bending operation. Such mandrels feature a longer solid cylindrical body, with a set of round balls attached to one side with an elastic cable.

They are made of brass or steel and have a similar diameter as the cylinder. The ball mandrel can be used with pipes having regular wall thickness (wall factor from 15 to 70), and a smaller radius. You can estimate the wall factor of a tube by using this formula:

Wall factor = Outside diameter/Wall thickness

13. How to Avoid Wrinkles When Using the Mandrel Bender?

Sometimes wrinkles will still appear when using the mandrel, this time you need to check the mandrel insertion rate, the quantity of lubricant oil in use, and the form of the wiper die to eradicate wrinkles.