Mistakes You're Making With Your Tube Bending Machines

Approximately before the 1940s, most of the technicians at metal manufacturing plants would manually bend small-diameter tubes. At those times it was common to yield inaccurate dimensions, bad angles, and cosmetic imperfections, such as wrinkles on the inside of the bend.

But thankfully these all changed after the 1940s, new inventions invaded and CNC programming was introduced to make the work easy and accurate. And CNC tube bending machines have been introduced to the market which made precise measurements with machines designed to perform the job flawlessly.

Now, with the help of CNC tube bending machines or CNC tube benders, we can bend to precise measurements with machines designed to perform the job flawlessly. These are used for pipe & tube fabrication primarily for bending tubes.

What Is CNC Bending?

CNC bending machine is a machine that has Computer Numerically Controlled programming software where the operator uses the programming software to feed the data of the operation or operations required to perform those operations automatically. And CNC tube bending machines usually use a combination of presses and rollers to guide the tubes and pipes along the process.

Today you can see most industries are depending on CNC banding machines as it only needs human assistance, not constant guidance. The introduction of CNC bending made it more productive and efficient by using automation.

What Are The Main Parts Of A Tube Bending Machine?

Bend Die

The bend dies, bend form or the radius die, Part of otary-draw bending machine, where the selection of die is very crucial, as the tube’s inside radius depends on it. The drawing process produces the necessary bend when the tube clamps to the bend die.

Clamp Die

There is a clamp die that prevents the pipe from slipping. The clamps die presses the tube onto the bend die, to prevent slipping.

Pressure Die

To makes sure the tube follows the bend die’s contour, there will be a pressure die.

Wiper Die

The purpose wiper die is to avoid the formation of any humps on the inside radius, which is placed just after the bend die. Why wiper die is placed just after the bend die? It is because, during the forming process, the material turns plastic during bending, and these result in wrinkles with large deformations.

Mandrel

It is difficult to Bend a small radius, thin tubes, or harder materials as we won't get a perfect outcome, to overcome such a difficult situation to keep the tube from collapsing a mandrel is necessary which can come in handy.

Different Tube Bending Machines

There are different kinds of tube Bending Machines to choose from when you want to bend the tubes. These Tube bending tools help to bend a tube without flattening it. Tube and pine bending machines come in different forms depending on the choice of a bending process like required bending radii, material, etc.

The different tube bending machines include;

Rotary Draw Bending Machine

Rotary Draw Bending Machines are the most common type of tube bender which are used to make handrails, frames, automotive roll cages, handles, etc. It allows the production of complex parts in batches because it is a highly accurate and programmable machine.

The bend die starts turning around its axis when the machine operator secures the tube or pipe on the machine with a clamp die, and the stationary pressure die will make sure that the tube follows the bend die radius.

If there is a difficult job where deformations are not allowed then adding a mandrel and a wiper die is a possibility to secure a better outcome. Like, a tube needs more support when it is with a large diameter and a small wall thickness.

Roll Bending Machine

These 3-roll benders are similar to sheet metal roll benders, which are commonly used for achieving large radii bends. In this 3-roller bender, the two lower rollers have a fixed position and the upper roller’s height is adjustable.

Until obtaining the optimal result, with back-and-forth movement between the rollers, the tube bends. Roll bending machine is suitable to make coils of pipe, long bends with a large radius, etc. because with this we can achieve an excellent result by causing little deformation in the cross-section.

Ram Bending Machine

If you ask, which is the simplest pipe bender on the market then that will be Ram bending machine. Placing the stationary dies onto the work bed is the first process to be done in a Ram bending machine and then the distance between the dies regulates the length of the bend and the bending angle.

When everything comes in its correct position then the ram pushes against the pipe where the bending radius depends on the radius of the ram. The ram can effectively perform the metal forming as the outside wall of the tube is supported by the dies.

The pipe ends with an oval cross-section when there is no internal support. And this makes Ram bending suitable only if the deformation of the cross-section is not an issue. The Ram bending machine is applied where there is a need for simple bends, which needs less importance for accuracy and a constant cross-section.

Vector Tube Bending Machine

Vector Tube Bending Machine has a similar principle as rotary draw bending which is meant for high-quality results. These machines work on an automatic feeding system which makes it fast and very precise in performance since the pipe forms around a rotary draw. Vector Tube Bending machine is suitable for bending high-strength materials in the field of aerospace and automotive industry.

Orbital Head Bending Machine

Orbital Head bending machines works by using both automation and computer controls. They can rotate the heads and collets around the tubes and pipes, to increase efficiency and productivity. The automated feeding and offloading of these machines make them suitable for air conditioning, automotive, and other complex parts.

Induction Bending Machine

The first process in an induction bending machine is to draw a profile with a die. At the bending point, there will be an induction coil through which the metal heats up when pressure is applied to this hot metal workpiece by allowing energy-efficient bending.

Since it’s an accurate method, it does not require mandrels. A large variety of bend angles are available and a wide range of pipe sizes fit the same induction bending machine, making it more beneficial for the user.

An induction bending machine is applicable in large industrial structural parts, short radius bends, heating system parts, thick-walled parts, etc.

Mistakes In Tube Bending Machines

Now let us come to our main point. Even though bending a metal tube requires a powerful machine, if it is used incorrectly, things can go wrong quickly. An improperly bent tube underperforms and wears out quickly and they will look bad without any doubt.

Following mistakes can lead to improper bending, if you can't make the best bends that meet your needs and your budget, you need a balance of power, precision, speed, safety, and cost-effectiveness. They are;

- When there is too much clearance between the mandrel and the tube

- When the pressure die has not enough pressure

- If the lubrication is inadequate or excess.

- Chances of tube slipping in clamp die

- When the mandrel is not far enough forward

- Wiper die not seated properly in bend die or worn or of improper fit

Mistake That Leads To Improper Bending?

- Make sure between the D roller and the clamp arm of the bending shoe there is a clearance of about 3/8 inch. To make it easier to see the gap, you can place a piece of white paper between the rollers.

- Make sure the 3 shafts of the blender that is Shafts 1 (low bend speed) and 3 (high bend speed) must be cranked clockwise to bend the tube and shaft 2 (medium bend speed) must be cranked counterclockwise. There is a chance for the crank to spin and cause injuries, so make sure to never release the hand crank while the tube is under load.

- Check the inboard pressure on the pressure die, If the mandrel and wiper die are in the proper locations. To hold the tube into the die, you may need to apply more pressure on the pressure die and gradually adjust it slowly until you have no wrinkles. And finally, check mandrel fit.

- The end of the tube must extend past the end of the clamp arm while inserting the tube, to prevent potential damage to the tube during bending.

Mistakes Made While Buying Tube Bending Machines

Now let's discuss the mistakes that can happen to the technician.

Misplaced Pressure

For precise bending, the pressure needs to be applied in the right place to the right extent. Too much pressure can break your tools or cause a bad bend and it doesn’t compensate for using the wrong tools or a poorly placed die.

Too much pressure can cause a bad bend or break your tools.

The two consequences can happen when there is misplaced pressure. The first scenario is If too much pressure is placed on the point of the bend, this will result in the tube flattening or breaking. The second scenario is if pressure is placed too far away, which can result in the buckling of the tube.

Using the Wrong Machine for the Job

CNC benders are powerful and versatile which can offer greater accuracy. If you have complex shapes and advanced bends, then CNC (computer numerically controlled) bending machines are the best.

But the question you should ask hear is, whether you need a CNC bending machine for simple bending works. No, Right? With a normal manually controlled machine you can do all simple bending work and you can also increase speed and save money.

On the other hand, if you have complex bending work then you have to choose CNC bending machine or something advanced. To maintain shape and integrity, some bends have a mandrel inserted in the tube. And the empty bending machine is a better solution for flattening as it allows up to 15% flattening.

So according to the bending needs, you have to select the branding machines.

Too Much Flattening

Too much flattening will cause a serious problem while bedding a tube, even though some flattening is okay on certain jobs. Too much stress placed on the outside radius during the bending process can result in it an ill-shaped tube.

For this, you need to reduce stress and utilize a larger bend centerline radius. To avoid too much flattening either you can use a mandrel or increase the wall thickness of the tube beforehand.

Inadequate knowledge of Bending Machine

You should acquire great knowledge about the bending machine before buying or using that product. There are various types of tube bending machines based on their power source that you need to keep in consideration. Like;

Hydraulic Benders: The bending machines are more powerful than electric tube benders They are powered by hydraulics and shop air which enables them to bend various types of pipes other than conduit pipes.

Manual Benders: These bending machines are made to accomplish precision bends with soft metal pipes that are operated manually using hands. These are mainly used by DIY users as well as hobbyists.

Electric Benders: These powerful electrical blenders are used to bend rigid pipes which are used for creating demanding and complex bends.

Prioritizing Money over requirements
Of course, you need to consider the budget while buying the tube bending machine. But don't you think it’s better to put its use as the priority?

Because many bending problems stem from the wrong choice of machine or inferior quality machines. Please consider the specifications of tubes, required precision, rigidity or softness of tubes, and usage interval of the machine as a factor to avoid such situations.

Buying to Use at its Maximum Capacity:

If a bedding machine is used up to its maximum capacity it can result in several tube bending problems. And the problem is that users have the tendency to use it at its maximum capacity.

It is always advised to buy a tube bending machine that can offer a leeway of 10% or 20%, as it is important to consider the tolerance that differs across various grades of steel.

Choosing a Machine that requires Manual Labor:

Yeah, money is important, but don't you think you should give priority to the requirement more than money when buying a tube bending machine? The user always ends up buying affordable manual pipe-bending machines. In order to save that money, they will end up choosing a manual machine that will become a cause for labor-intensive and mundane.

Of course, these machines can bring good results, compared to hydraulics and electric tube blenders. But if there is a time constraint for the work, it can take more time for pipe bends, rotational positioning, and lengths may add up. We recommended buying a tube bending machine based on the volume of bending done.

Buying it by Overlooking Risks:
All bending machines perform the same but may have different features, as you can find pipe bending machines with different specifications across brands. Before choosing a machine should have a thorough understanding of the features of these products and their ease. In addition to that, you also need to analyze the various risks and challenges that you may face due to their features.

Buckling and Wrinkling:
A proper bend should be as smooth as the tubing leading up to it and not wrinkles or buckling. How do wrinkling and buckling happen? when the cross-section of the bend fails to support the pressure of the bending, this is when we can see buckling and wrinkling. And usually, it happens from applying pressure too far away from the die or not using a mandrel when you should.

Conclusion On Mistakes You're Making With Your Tube Bending Machines

From the above explanation, you might have got an idea about the mistakes you can make while buying a tube bending machine. There are a lot of things you need to analyze before buying a tube bending machine. For this, you need a bit of expert advice.

At Hytek Marketing you can explore many tube bending machines and you will get expert advice to choose the best one for you. We are one of the best bending machine suppliers in GCC, which have a lot of brands with different specifications and features. Please contact us for any information and queries regarding bending machines.