Pipe benders have been around for a very long time, and through the years they have undergone tweaking and perfecting until there are now several types of pipe benders available on the market. Since there has been a significant amount of development in the pipe and tubing industries, benders are now available in many shapes, sizes, and advancement to cover today's current demands. Which one of these benders you need will all depend on your project and intended use. Each project will likely require a different approach and perhaps even a different pipe bender depending on its mode of operations, speed of operation, and the effectiveness and reliability of each device.
Materials That Can Be Bent With a Pipe Bender
All benders use one of four methods. Ram bending is the easiest and most affordable method. Pipe benders are controlled at each end and a ram bends the pipe in the middle. This is only used for light weight pipe. Rotary draw bending is the most popular method since it maintains the diameter of the pipe without warping. This method is used in tube bending machines to form exhaust pipes, process pipes, and for any aluminium or stainless steel projects that will not allow for any interior warping. Ring roll bender is used for shaping pipes with a large diameter. There are three rollers, one at the top and two at the bottom.
How Hydraulic Roll Benders Work
The interior of the pipe is supported by a flexible mandrel, which ensures that the interior diameter of the tube is not deformed. As the pipe rolls through, the top roller exerts a downward pressure which bends the pipe. As the outside wall is stretched it becomes thinner while the inside wall becomes thicker due to the compressing of metal. The top roller pressure may be adjusted manually or hydraulically. Also, you can power two or three rollers at a time in order to make round shapes needed for drum barrels, awnings, etc.
When the proportion of pipe diameter to wall thickness is small enough, a pipe can be bent on a small radius without excessive wrinkling or flattening.
http://www.articlesbase.com/industrial-articles/pipe-bender-facts-to-consider-6030446.html