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Tubing Bender Basics

What is a tubing bender? If you're like me you might think it's a person with superhuman strength bending the bars of a prison cell. Or you might think of Bender, the crass bending robot from Futurama. But the topic of tube bending is actually fairly simple to comprehend and this article attempts to spell things out in a clear manner.

Starting at the very basics, a tubing bender is just that: a machine that bends a tube to the precise shape that is required. The tube can have multiple bends in different directions. Tubes are bent around what is called a die. The die controls the angle of the bend. The die remains stationary as the tube is loaded into the machine (either automatically or manually) and is bent around the die.
There are many applications for tubing benders spanning many different industries. For examples, look at a motorcycle - many parts of the motorcycle have been bent or formed by a machine. The motorcycles handlebars, exhaust system, sissy bar, luggage rack, even portions of the frame, are all likely to have been bent into their current shape by a tubing bender machine. Other examples of tubing benders include roll cages, automotive parts, railway parts, angle iron, rebar, sign frames, trailer frames, furniture tube frames, copper plumbing, hydraulic joints,  gym equipment, baby carriages and heat exchangers. The list could go on and on as the possible applications for tubing benders are almost limitless.
The tubing is typically cylindrical (or "round stock") but rectangular and square tubing can also be bent. 
The materials used vary from application to application, but the one thing they have in common is that they're ductile. Ductile simply means the ability of a material to deform while it's being bent, or it's ability to deform due to tensile stress. In other words, if you bend a material, will it snap or will it stretch with the bend? 
Ductility is commonly confused with malleability. Ductility refers to the plasticity of the material under tensile stress. Malleability is the materials ability to deform under compressive stress. Think of tensile stress as tension against an object, for instance bending it. Compressive stress could be hammering, stamping, pressing or rolling the material. 
In tubing bender applications, much thought goes into the type of material that is used. For instance, depending on what the desired shape of the product to be bent will be, steels with different alloys might be used (for instance increasing the level of carbon in steel will decrease the ductility of it). The fracture point of the material is determined by something called "ductile-brittle transition temperature" (or DBTT).
Common materials used (and those used by Bendco) include stainless steel tubing, aluminum tubing, steel round tubing, steel square tubing,  steel rectangular tubing, aluminum tube assemblies and copper tubing.
A common type of bend is an elbow bend. This is bending the tube at an angle of between two degrees and ninety degrees. A U-bend tube is one which is bent one hundred and eighty degrees.
In some bends, something called a mandrel in placed in the tube to prevent it from collapsing. The mandrel is inserted and stays in the tube at the location of the bend, bending with the tube and reinforcing it. Think about the material of the tube as it's being bent: the outer part of the bend is stretched out, while the inner portion is compressed. The mandrel helps prevent wrinkles or creasing due to the stress of the bending.
Hopefully this was an enlightening and informative introduction to the process of tubing benders.  Let us know how we can assist you with any tubing bender applications!


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