There are four factors you need to consider when it comes to tube bending: the material and machine you have along with the tooling and lubrication available. Here are basics on how to bend tubing and come up with the perfect bend at all times.
Learn the properties of the materials you’re working with, whether it’s a pipe or tube. When it comes to using a bending machine, make sure you’re familiar with the following: the centerline, radius, as well as the wall thickness and even the outside diameter.
Other bending factors you have to consider include the inside bend radius or what’s usually also known as the intrados, the outside bend radius or what’s termed as the extrados. There’s also the centerline radius or neutral line where no compression or stretching happens.
Tubes usually undergo springback after a bend. And this produces a bend with radial growth. The harder the tube and the smaller your centerline radius is, the greater the springback as well as radial growth you get.
Ram type bending is the oldest and most affordable way to bend a tube or pipe. It’s not as easy to control though, which can be a downside if you’re working on applications with tight bending tolerances.
In construction applications, it’s common to use roll bending with a two-roll, pinch style roll bender. And if you’re working on symmetrical workpieces that use identical bends on either side, then compression bending is a common choice, says the Fabricator. And for work that requires the utmost precision, rotary draw setup is the perfect way to achieve the bend.
When it comes to tooling, you need to factor in radial growth of the material as well. Too much of it means you’ll have to make certain adjustments or use a bend die, one with a smaller radius. Also consider good welds since an inconsistent weld bad could compromise operations. Also, certain types of tubes need a series of balls that flex on the end of your mandrel in order to support the tube ID in the bend itself. Be careful that they don’t break inside the tube during bending.
Synthetic and nonpetroleum-based lubricants often used. Often in paste or gel from, you can dilute this to any consistency for whatever application you have in mind. Just remember that for heavy duty bending, more lubrication is better.
These are just a few tips to help you out. With the right tools, lubrication, material and machine, it’ll be easy to achieve the perfect bend you want.